179353073-EHB-CC100-CC200-EN-pdf

TRAINING MANUAL

2002CSD •

EHB - Hydraulic components of ENGEL injection molding

machines(ENGEL Hydraulic Basics)

ENGEL AUSTRIA GmbH.Ludwig-Engel-Straße 1 A-4311 SchwertbergTelefon: A+07262/620-0Fax: A+07262/620-6009

This manual has been established for information and/or trainings. It is no component of the instruction manual.

Exclusion of liability:ENGEL does not take over any guarantees regarding this manual. For mistakes included in it,consequential damage or damage in causal relation due to the information included in this manualENGEL cannot be made liable.

These documents remain our property and must not be copied without our written consent. Its con-tents may neither be made known to third parties nor be used for non-approved purposes. It onlyserves the internal benefit and use. Each violation will be sued according to §12 and §13 UWG.

© Copyright by ENGEL AUSTRIA GmbHA-4311 Schwertberg

EHB Training manualVersion:G/11/25/10/2

GENERAL (1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 ENGEL - COMPANY GROUP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 ENGEL - COMPANY HISTORY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

BASICS OF THE HYDRAULICS (2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131 HYDRAULIC FORCE AND ENERGY TRANSMISSION IN COMPARISON WITH THE MECHANICS AND ELECTRICAL EN-

GINEERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141.1 DISADVANTAGES OF HYDRAULIC CONTROL SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141.1.1 RELATIVELY HIGH LOSSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141.1.2 DIRT SENSITIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.1.3 DEPENDENCE ON THE PROPERTIES OF THE TRANSMISSION MEDIUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.1.4 SLIPPAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.1.5 DANGER IN CASE OF FRACTURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.1.6 SHORT LIFE OF HIGHLY STRESSED COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.2 ADVANTAGES OF OIL-HYDRAULIC CONTROL SYSTEMS AND DRIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.2.1 OPEN AND CLOSED LOOP CONTROLABILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151.2.2 ENERGY TRANSMISSION POSSIBILITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 MASS, PRESSURE, FORCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 BASIC CIRCUIT DIAGRAM OF A HYDRAULIC CIRCUIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

HYDRAULIC FLUID AND ACCESSORIES (3). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 HYDRAULIC FLUID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.1 HYDRAULIC FLUID SOILING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.2 WATER IN THE HYDRAULIC FLUID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191.3 AIR BUBBLES IN THE HYDRAULIC FLUID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.4 SURFACE FOAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.5 OVERHEATING OF THE HYDRAULIC OIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.6 EXCESSIVELY HIGH EXTERNAL LEAKAGE LOSSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 201.7 MONITORING OF HYDRAULIC FLUIDS AND EQUIPMENT (INSPECTION) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211.8 CARE OF HYDRAULIC FLUIDS AND EQUIPMENT (MAINTENANCE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 OIL CONTAINER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222.1 TASK OF THE OIL RESERVOIR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222.2 HYDRAULIC OIL CHANGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233 ADDITIONAL DEVICES FOR THE TANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.1 FILLING AND VENTING FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 243.2 OIL LEVEL SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.3 OIL LEVEL CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 253.4 THERMOSENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263.5 SUCTION LINE WITH BALL VALVE AND ELECTRIC MONITORING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264 OIL PREHEATING, COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264.1 TASK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 264.2 PREHEATING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.3 COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.3.1 SHELL-AND-TUBE EXCHANGERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274.3.2 PLATE HEAT EXCHANGERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 284.4 OIL TEMPERATURE CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295 FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305.1 TASK OF THE FILTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305.2 IMPACT OF THE SOILING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305.3 SUCTION FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305.4 LOW-PRESSURE FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315.4.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.4.2 MAINTENANCE INSTRUCTIONS - LOW-PRESSURE FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325.4.3 PRESSURE FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 HYDRAULIC ACCUMULATORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 346.1 TASK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356.2 COMPONENTS AND MODE OF ACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356.2.1 COMPONENTS BLADDER ACCUMULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 356.2.2 COMPONENTS DIAPHRAGM ACCUMULATOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366.2.3 MODE OF ACTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366.2.4 SAFETY HINTS FOR PRESSURE ACCUMULATOR EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377 PRESSURE MEASUREMENT CONTROL EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387.1 MANOMETER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 387.2 PRESSURE TRANSDUCER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

HYDRAULIC PUMPS AND HYDRAULIC MOTORS (4). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 411 HYDRAULIC PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Creation date: 18.03.2003Printing date: 20.3.2003 5


2 LOW-PRESSURE PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412.1 VANE-CELL PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412.2 SCREW TYPE PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 423 HIGH-PRESSURE PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433.1 INTERNAL GEAR PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 433.2 VARIABLE DISPLACEMENT PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.3 RADIAL PISTON PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 453.3.1 PRESSURE AND THROUGHPUT CONTROLLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473.3.2 START-UP OF THE RADIAL PISTON VARIABLE DISPLACEMENT PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.3.3 RADIAL PISTON PUMP WITH ELECTROHYDRAULIC ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 483.4 AXIAL PISTON PUMP (TAPERED WASHER PUMP WITH ADJUSTABLE VOLUME THROUGHPUT) . . . . . . . . . . . . 494 HYDRAULIC MOTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504.1 ANNULAR GEAR MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 504.2 GEAR FOR INTERCONNECTING TWO DANFOSS HYDRAULIC MOTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 524.3 RADIAL PISTON HYDRAULIC MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

HYDRAULIC VALVES (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551 DIRECTIONAL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551.1 TASK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551.2 GRAPHICAL SYMBOL AND DESIGNATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551.2.1 SWITCH POSITION AND CONNECTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 551.2.2 VARIANTS OF THE FLOW RATE SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 561.2.3 ACTUATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 572 SHUT-OFF VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592.1 SIMPLE CHECK VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592.1.1 TASK, FORMS OF CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 592.1.2 CONSTRUCTIVE DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602.1.3 USE OF CHECK VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 602.1.4 SHUTTLE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612.2 PILOT CONTROLLED CHECK VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612.2.1 APPLICATION, MODE OF ACTION, GRAPHICAL SYMBOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 612.2.2 PILOT CONTROLLED DOUBLE CHECK VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623 CARTRIDGE TECHNOLOGY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623.2 COMPONENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 623.2.1 CONTROL BORES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 633.2.2 BUILT-IN VALVES AND THEIR VARIANTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 643.2.3 COVER PLATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 664 DIRECTIONAL VALVE FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674.1 DIRECTIONAL VALVE WITH INTERNAL VALVES 1:1,6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 674.2 SWITCHING TIME INFLUENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 675 PRESSURE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685.1 PRESSURE RELIEF VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 685.1.1 DIRECTLY CONTROLLED PRESSURE RELIEF VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 695.1.2 PILOT OPERATED PRESSURE RELIEF VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 705.2 PRESSURE RELIEF VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 725.2.1 DIRECTLY CONTROLLED PRESSURE RELEASE VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735.2.2 PILOT OPERATED PRESSURE RELIEF VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 735.3 PROPORTIONAL PRESSURE VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 746 VOLUME/FLOW CONTROL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 756.1 THROTTLE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766.1.1 FLOW LAW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766.1.2 THROTTLE FORMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 766.1.3 CONSTRUCTIVE DESIGN OF THROTTLES AND THROTTLE CHECK VALVES . . . . . . . . . . . . . . . . . . . . . . . . . 776.2 FLOW CONTROL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786.2.1 TWO-WAY FLOW CONTROL VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786.2.2 FLOW CONTROL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 786.2.3 THREE-WAY FLOW CONTROL VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796.3 PROPORTIONAL THROTTLE AND/OR FLOW CONTROL VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 796.4 PROPORTIONAL DIRECTIONAL VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 807 MOOG SERVOVALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 817.1 MAINTENANCE INSTRUCTIONS D061-6 MOOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 847.2 MAINTENANCE INSTRUCTIONS D641/661, D651/656, D659 MOOG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 867.3 RANGE D061-7 AND D630-* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 877.4 ERROR POSSIBILITY AND CHECK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Creation date: 18.03.20036 Printing date: 20.3.2003


BARREL (6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

HYDRAULIC SYMBOLS (7) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971 ENERGY CONVERSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971.1 HYDRAULIC PUMPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971.2 HYDRAULIC MOTORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 971.3 BARREL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 982 ENERGY OPEN LOOP CONTROL AND ENERGY CLOSED LOOP CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 992.1 DIRECTIONAL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 992.2 SHUT-OFF VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1002.3 INTERNAL VALVES ( CARTRIDGE ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1002.4 PRESSURE VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1012.5 VOLUME/FLOW CONTROL VALVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1023 ENERGY SOURCES, ENERGY TRANSMISSION, ACCESSORIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033.1 PIPINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033.2 ENERGY SOURCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1033.3 ATTACHMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

MALFUNCTIONS ON HYDRAULIC DEVICES (8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051 PUMP AND MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051.1 PUMP DOES NOT CONVEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1051.2 PUMP OR MOTOR PRODUCE HEAVY NOISE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1061.3 PUMP OR MOTOR OVERHEATED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1061.4 PUMP DOES NOT DEVELOP ANY PRESSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1071.5 SPEED LOSS ON THE MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1071.6 MOTOR DOES NOT TURN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1071.7 SHAFT PLAY TOO BIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1071.8 LEAKAGE ON PUMP OR MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082 DIRECTIONAL VALVES (SOLENOIDS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082.1 SLIDE JAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082.2 SLIDING MAGNET DOES NOT SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082.3 PRESSURE VALVE DOES NOT SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1082.4 SLIDE OVERHEATED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1092.5 SLIDE PRODUCES HEAVY NOISE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1092.6 LEAKAGE ON THE SLIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1093 PRESSURE VALVE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1093.1 VALVE FLUTTERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1093.2 VALVE JAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1103.3 VALVE DOES NOT SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1103.4 VALVE OVERHEATED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104 THROTTLE VOLUME/FLOW CONTROL UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1104.1 DEVICE DOES NOT CLOSED LOOP CONTROL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1105 BARREL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1115.1 CYLINDER WANDERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1115.2 CYLINDER JAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1115.3 NONUNIFORM RUNNING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116 FILTER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1116.1 BAD FILTERING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1117 TANK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1127.1 OIL SOILED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1127.2 OIL FOAMED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1127.3 TEMPERATURE TOO HIGH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1128 OIL COOLER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1138.1 BAD COOLING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1138.2 WATER IN THE OIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1139 SUNDRIES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1139.1 SOILING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1139.2 OIL FOAMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1139.3 TEMPERATURE FLUCTUATES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113



GENERAL (1)

1 PREFACE

One of our most essential enterprise aims, the production of high-quality products of constantquality and reliability, is really effective then when the quality of these products can be utilizedby our customers satisfactorily over a long period of time.In order to promote the problem-free utilization, we have developed several seminars with theaim to create with this service for our customers the possibility to impart by appropriate,carefully directed education to the expert standing in practice the knowledge and equipmentfor the handling as well as to become thoroughly familiar with the functions of our products.Proper operation contributes essentially to avoid machine malfunctions and breaks inproduction and leads to bigger operational reliability as well as to higher life of our products.

2 ENGEL - COMPANY GROUP

Range of products

Injection molding machines for processing thermoplastics and thermosets

2-4 Units-injection molding machines for manufacturing multi-color or multi-materialcombination injection molded parts of thermoplastics and in combination withelastomers

Horizontal and vertical elastomer injection molding machines

Horizontal and vertical low-pressure injection molding lines for manufacturing surfacetreated parts (Tecomelt for parts with paint film or textile surface)

Modular injection molding production units including automation equipment

Multi-axial linear robots

Injection molds for sandwich molded parts

Special metal components with emphasis resistance to wear

Foundation: 1945 by Mr. Ludwig Engel

Legal position concerning prop-erty:

The enterprise is to 100 % in family property

Turnover (Business year 2001/2002):

Austria group: 440 million EURENGEL-Worldwide: 533 million EUR

Employees (Business year 2001/2002):

Austria group: 2.412ENGEL worldwide: 3.316

Export rate: approx. 93 %

Most important export countries: Germany, France, Italy, USA

Creation date: 18.03.2003Printing date: 20.3.2003

General (1)9


Engel marketing corporations and sales offices:Germany (Hanover, Hagen, Nuremberg), Switzerland (Frauenfeld), Czech Republic (Prague),Hungary (Pomaz), Netherlands (Houten), Denmark (Solro/d Strand near Copenhagen andHobol near Oslo for Norway), Sweden (Upplands Väsby near Stockholm), Great Britain(Warwick), Ireland (Cork), France (Wissous near Paris), Italy (Vimercate near Milan), HongKong/People’s Republic of China (Hong Kong and office Singapore for Singapore andMalaysia), South Africa (Randburg near Johannesburg), Mexico (Mexico City), India(Mumbai), Brazil (São Paulo).

Market position: ENGEL is the largest Austrian enterprise of its industry and belongs to the worldwide leading manufacturers of injection molding machines.Market share in Europe lies at about 17 %.Market share in Germany at approx.. 20 %.

Production plants at home: OÖ: ENGEL AUSTRIA GmbH, SchwertbergOÖ: ENGEL AUSTRIA GmbH, DietachOÖ: ENGEL AUSTRIA GmbH, SteyrNÖ: ENGEL AUSTRIA GmbH, St. Valentin

Production plants abroad: Canada: ENGEL Canada Inc. Guelph, OntarioCanada: ENGEL Automation Guelph, OntarioUSA: ENGEL Machinery Inc. York, PennsylvaniaKorea: ENGEL Machinery Korea Limited Pyongtaek

ENGEL holding companies, Austria

ENGELCanada, Inc.,Canada

ENGELMachinery Inc.,USA

ENGEL AUSTRIA GmbHSchwertbergAustria

ENGELMachinery Korea Ltd.,KOREA

ENGEL Deutschland GmbH ENGEL Italia S.r.I.

ENGEL CZ, spol s.r.o.

ENGEL Hungaria Kft.

ENGEL Machinery HK Ltd.

ENGEL Machinery India Pvt. Ltd.

ENGEL South Africa (Pty) Ltd.

ENGEL Polska Sp. z.o.o.

ENGEL Finland Oy

ENGEL de Mexico S.A. de C.V.

ENGEL AutomatisierungstechnikDeutschland GmbH, Hagen

ENGEL France S.A.

ENGEL U.K. Limited

ENGEL Ireland Ltd.

ENGEL Sverige AB

ENGEL Nederland B.V.

ENGEL (Schweiz) AG

ENGEL Danmark A/S

Hongkong

Solroed Strand, DK

Oslo, Norway

Isernhagen near Hanover

Hagen

Nuremberg

Singapore

Shanghai, China

Production

Marketing and service

ENGEL marketing subsidiaries:

ENGEL automation center:

General (1) Creation date: 18.03.200310 Printing date: 20.3.2003


3 ENGEL - COMPANY HISTORY

Messrs. ENGEL was founded in 1945 by Ludwig Engel in Schwertberg, Upper Austria wherestill the parent company is. After one has produced machine components and cable railwayaccessories in the first few years, in 1948 the first hand operated bakelite press was taken upinto the production program. With it the foundation stone for the production of plasticsprocessing machines was laid. In 1955 the series production of injection molding machines forthe processing of plastics was started. At the same time the first export activities were started.

In the year of 1965 the founder of the company, Mr. Ludwig Engel died and Mrs. Irene Schwarz(née Engel) and Mr. Georg Schwarz took over the management. Then with 438 employees aturnover of 120 million ATS was achieved.

In the course of reinforced foreign activities a worldwide marketing network was built up in themiddle of the 60ies. Today the export share is more than 90 % of the turnover whereby about56 % are achieved in the EU region. ENGEL is represented in more than 70 countries, of themwith 20 own marketing subsidiaries. The first foreign production plant was established inGuelph, Canada in 1977.

With the start of the production of robots and automation equipment in the separate factorySteyr in the year of 1986 an important and successful step into a new production branch wascarried out. In January 1998 the production of the ENGEL robots moved into a new, largerfactory in Dietach near Steyr.

Since 1988 large machines have been produced in the factory St. Valentin (approx. 20 kmaway from the parent factory Schwertberg). Fully automatic production lines and logisticsystems enable a modern and economical production of large machines. In 1994 ENGELcame on the market with the innovation 2-platen large machines technology and was honoredfor it by General Motors worldwide as first manufacturer of injection molding machines with the”Supplier of the Year Award” in 1997, 1998 and 1999.

With building the factory for large machines in York, Pennsylvania, USA, in the year of 1989the market position - specially in the automobile sector - has been reinforced further also in theNorth and central American region. In 1994 followed the extension of the factory with doublingthe production area. In the year of 1995 the field automation technology was madeindependent with a new factory in Guelph, Canada also in North America.

At the end of 1997 Georg and Irene Schwarz entrusted the management of the operativecorporations in Austria to 4 managing directors whose spokesman is Mr. Peter Neumann.

Today ENGEL is the largest Austrian enterprise of its industry and is as individual mark theworldwide largest manufacturer of injection molding machines. In the past business year 2000/2001 the total turnover was 8.2 billion ATS (593 million EUROS). At present worldwide around3300 people are employed. In the business year 1999/2000 ENGEL was honored as firstmanufacturer of injection molding machines with the highest quality prize of Messrs Ford, the”Q1 Award”.


General (1)11


ENGEL - MILESTONES IN THE COMPANY HISTORY

1945 Foundation of the enterprise by Mr. Ludwig Engel1948 Expansion of the production to the construction of cable railways and hoisting

plantsManufacture of the first mechanical toggle lever presses

1950 Manufacture of the first hand operated injection molding machines and concen-tration of the production on this field

1955 Changeover of the production to series production of plastics processing machines

1965 After the death of the founder of the firm: Takeover of the management by Mr. Georg Schwarz and Mrs. Irene Schwarz (née Engel)

1966-1970 Extension of the foreign marketing activities by expansion to 40 foreign repre-sentatives

1968 Standard equipment of the machines with electronic control system1972 Foundation of ENGEL Danmark A/S in Copenhagen as first marketing and ser-

vice corporation outside Austria1974 Foundation of ENGEL Canada Inc. in Guelph, Ontario, as marketing and ser-

vice corporation for the North American market1977-1979 Expansion of ENGEL Canada Inc. to the production factory1980 Development and production of high performance handling and robot systems1983 Opening of the new ENGEL technical demonstration hall in Schwertberg with

training center and toolmaking department, electrical engineering, electronics and apprentices’ training shops. Expansion of the in-plant software department for the ENGEL microcomputer technology

1986 Foundation of ENGEL Machinery HK Ltd. in Hong Kong as first step into the Far East market (China and South East Asia)

1986 Start of the production of robots and automation equipment in the separate fac-tory Steyr/Münichholz

1988 Opening of the factory for large machine in St. Valentin, Lower Austria, of the ENGEL Maschinenbau Gesellschaft m.b.H.

1989 Opening of the factory for large machines ENGEL Machinery Inc. in York, Pennsylvania, USA

1993 Enlargement of the production plant ENGEL Canada Inc., Guelph1994 Doubling of the production area of the ENGEL Machinery Inc., York, USA1995 Transfer of the production of robots for North America into newly acquired fac-

tory premises of the ENGEL Canada Inc.1997 Extension of the machine assembly hall and of the administration building in the

headquarters Schwertberg1997 Foundation of ENGEL Machinery Korea Limited as marketing and service cor-

poration with the intention to begin the planning work for a production factory in Korea

1997 Family Schwarz entrusts the management of the operative corporations in Aus-tria to a management team of four persons, with Mr. Dr. Neumann as spokes-man

1998 Opening of the new factory for Automatisierungstechnik Gesellschaft m.b.H. in Dietach near Steyr

1999 Completion of the expansion stage III of the ENGEL factory for large machines in St. Valentin

2000 Laying of the foundation stone and construction beginning for production fac-tory Korea for small and medium-sized machines

2001 Opening of the production factory in Korea. Start of the machine assemblyPresentation of the ”E-MOTION” range of machines

General (1) Creation date: 18.03.200312 Printing date: 20.3.2003


BASICS OF THE HYDRAULICS (2)

The question ’’What is hydraulics’’ can be answered for the technology like that:By hydraulics one understands the transmission and control of forces and movements byliquids.Hydraulic plants and hydraulic devices are widespread in the technology. They find e.g.application in the

Machine tool building

Press manufacture

Plant construction

Vehicle construction

Shipbuilding

Plastics processing machine construction

The advantages of the hydraulics lie in the transmission of big forces when employing smallcomponents and in the good open and control loop controlability. The switchgear can also beremote controlled (mechanically and electrically) well. The start-up from the standstill underhighest load is possible with hydraulic cylinder and with hydraulic motors. By correspondingswitchgear the inversion of the direction can be enabled fast. The hydraulic devices have ahigh life by autolubrication.

Conversion of energy in hydraulic plants

But these advantages are also faced with disadvantages. In many cases the disadvantages liein the transmission medium, in the hydraulic fluid itself. In the high pressures of the hydraulicfluid lie dangers of accident. Therefore it must be paid attention to that all connections aretightened firmly and are tight. So the hydraulics has special advantages and crucial points -like the above mentioned ones. In connection with the electrical engineering, mechanics andpneumatics good solutions of problems of production technology can be achieved.

Drive

Electric motor internal combus-tion engine

mechanicalEnergy

Hydraulic energy

Hydraulic energy

mechanicalEnergy

electric or thermal energy

Hydraulic pump

working element to be confirmed

Hydraulic open and closed loop control devices

Consumer

Hydraulic cylin-der hydraulic


Basics of the hydraulics (2)13


1 HYDRAULIC FORCE AND ENERGY TRANSMISSION IN COMPARISON WITH THE MECHANICS AND ELECTRICAL ENGINEERING

Here at first a general comparison between mechanical, electric and hydraulic form of theforce and energy transmission shall be made. The following systematy shows a comparison ofthe different types of transmission:

In the electrical engineering one distinguishes between power current and control engineering.Analogously to it one can divide the hydraulics up into the power and control hydraulics.

1.1 DISADVANTAGES OF HYDRAULIC CONTROL SYSTEMS

1.1.1 RELATIVELY HIGH LOSSES

Losses due to liquid friction and waste oil appear. The losses cause the bad efficiency.

Losses due to liquid friction

The liquid friction leads in pipes, elbows, throats and piston ports to losses which are speed-dependent.

Losses due to waste oil

Through gaps and seals pressure oil enters areas with low pressure; therefore the elementsrequire a high production accuracy and a good maintenance.

Transmission mode, transmission quanti-ties

mechanical hydraulic electric

Transmitability over large distances

bad good very good

Controlability bad good good

Safety about all equally good

Efficiency good bad bad

Availability for sale, flexi-bility in the structure, offer of components

bad (expensive) good (expensive) very good (cheap)

Basics of the hydraulics (2) Creation date: 18.03.200314 Printing date: 20.3.2003


1.1.2 DIRT SENSITIVITY

As especially in the high pressure hydraulics one works with very small cross-sections (e.g.control instruments), the components require an intensive filtering of the pressure oil. With aworking pressure of 160 bar a filter degree of 60 - 40 µm, at 320 bar however already 10 - 5µm are striven for. Low pressure makes the hydraulics dirt-insensitive (Long-life hydraulics).

1.1.3 DEPENDENCE ON THE PROPERTIES OF THE TRANSMISSION MEDIUMDependence on temperature

A temperature change causes a viscosity change of the oil. Thus changes of the leakagelosses, volume throughputs and speeds are caused, but a compensation of these effects isabsolutely possible.

Compressibility

Due to the compressibility an oil column standing under pressure is about 140 times moreelastic than a same steel column. The compressibility of the pressure medium is stronglyincreased by the air existing in the circuit. This has its origin either in the fact that the circuithas not been ventilated, that it is sucked in from outside or that it is separated from the oil, likeit is the case when cavitation appears. Due to the existence of air in the oil circuit a jerkyworking results, the reversal times are extended and the oil is heated up locally by adiabaticcompressions of the air bubbles contained in it (quick ageing).

1.1.4 SLIPPAGE

Leakage losses and compressibility cause that the hydrostatic drive e.g. of rotating andoscillating motors is not completely positive. Therefore when synchronizing two or severaldrives with different stress difficulties with the synchronism result (use of synchronism openloop and closed loop controls).

1.1.5 DANGER IN CASE OF FRACTURE

At the mineral oils used so far there is fire hazard. This is especially valid for the flighthydraulics when e.g. oil mist comes into contact with hot transmission parts. But also atdiecasting machines and in the mining a fire can arise due to leak and line break. Thereforetoday in many cases flame resistant fluids are employed.

1.1.6 SHORT LIFE OF HIGHLY STRESSED COMPONENTS

The high force density in the hydraulics leads to relatively quick wear of different components.The enumerated disadvantages can be eliminated in most cases by corresponding designmeasures.

1.2 ADVANTAGES OF OIL-HYDRAULIC CONTROL SYSTEMS AND DRIVES

1.2.1 OPEN AND CLOSED LOOP CONTROLABILITY

The open and closed loop controlability of the hydraulic elements and circuits is, as followsfrom the table, equal to that of the electric elements, good. The hydraulic variables to be openloop controlled are volume throughput and pressure. Both can be influenced by corresponding




components. Therefore the hydraulics is especially suitable for open loop controlled main andfeed motions at machine tools, plastics processing machines, for vehicle gears and allapplications at which good time behaviour is requested.

Simple structure of sequence control units

Thus the automation of work sequences is largely facilitated. The sequence controls arestroke-dependent (closing and injection movement), pressure-dependent and time-dependent.

1.2.2 ENERGY TRANSMISSION POSSIBILITY

A transmission of the hydraulic energy over mean distances is no problem. It occurs via pipesor hoses on fixed and/or moving machine parts, the complex resistivity making itself felt.Analogously to the electrical engineering the resistor of the hydraulic conduit is composed ofa resistive, a capacitive and an inductive component.

2 MASS, PRESSURE, FORCE

Definitions and conversions to the international unitary system (SI units). A material mass (tobe understood in the sense of an amount of substance) of 1kg produces on the earth a weightforce of 1kp.

According to the fundamental law of gravitation is:

According to the old system with the acceleration due to gravity g for the general accelerationa:

1 kp = 1 kg x 9.81 m/s²=9.81 kg m/s²

thus is 1 kp = 9.81 N For the practice is normally sufficient:

1 kp ~ 10N = 1 daN

P =F / A

p = pressure in barF = Force in daNA = Area in cm²

Formerly the pressure has been indicated in kp/cm².

As today for the force the Newton (N) is used,:

F= m x aForce Mass x accelerationkg m/s²

F = m x g

1 kp/cm²= 1 at (1 atmosphere)



When corresponding to the SI units the primary quantities for force (N) and area (m²) areemployed, one gets for the pressure the unit Pascal (Pa).

As the unit Pascal yields too high numerical values for the practice, one preferably works withthe unit Bar (bar)

As pressure indication one still finds psi (pound-force per square inch).

With the pressure indication in bar according to the SI units the absolute pressure (pa) ismeant

In the hydraulics the operating pressure is generally indicated with p, however. This is theexcess pressure.

1 bar= 10 N/cm²

1 Pa= 1 N/m²

1 bar= 100 000 Pa

1 bar= 14,5 psi

pü = 100 bar

pü = 0 bar

pu = 1.013 bar

Excess pressure

absolute pressure vac-uum

pa = 101.013 bar

pa = 1.013 bar

pa = 0 bar

0% VacuumAtmospheric air pres-




3 BASIC CIRCUIT DIAGRAM OF A HYDRAULIC CIRCUIT

Instead of simplified sectional drawings symbols (graphical symbols) are employed. Therepresentation of a hydraulic circuit with these graphical symbols is called circuit diagram. Therepresentation and meaning of the individual devices and functions are standardized in DIN 24300. In connection with the devices designations the respective graphical symbols are stillrepresented.

M

Barrel

Throttle valve

Directional valve

Pressure release valve

Shut-off valve

Tank

Pump

Tank

Drive motor



HYDRAULIC FLUID AND ACCESSORIES (3)

1 HYDRAULIC FLUID

The perfect function, life, reliability in operation and profitability of a hydraulic plant isinfluenced decisively by the hydraulic fluid.

The tasks of a hydraulic fluid are manifold:

Transmission of the hydraulic capacity from the pump to the cylinder and/or hydraulicmotor

Lubrication of moving parts, such as piston and slide sliding surfaces, bearings, circuitelements

Corrosion protection of the wetted metal surfaces

Carrying-off of impurities, abrasion, air etc.

Elimination of lost heat, arisen due to leakage and friction losses.

Corresponding to these tasks it must be paid attention to a perfect hydraulic fluid permanently.

1.1 HYDRAULIC FLUID SOILING

Solid impurities in the oil cause most damage in oil-hydraulic plants. They can lead tospontaneous failures, but often cause slow wear, which leads to performance and efficiencyreduction with following machine failures and repairs. When at hydraulic fluid examinations toohigh dirt content is determined, then for this the mentioned possible reasons exist:

Insufficient or missed plant cleaning and rinsing before first putting into operation orafter repairs.

Unclean transport, storage and maintenance devices.

Missed oil change.

Missing, too wide-meshed, clogged or defective oil filters.

Missing or not observed filter soiling display.

Too wide-meshed venting filter on the hydraulic oil reservoir.

Leaky hydraulic oil reservoir (cover, pipe inlets etc.).

Metal or seal abrasion from pumps, motors or cylinders.

Rust particles from the oil reservoir cover.

Dirt entry over defective seals.

Refilling-in of run-out waste oil.

1.2 WATER IN THE HYDRAULIC FLUID

Water penetrated into the hydraulic fluid promotes wear, soiling and corrosion of the plant,changes the oil properties and can thus lead to plant malfunctions. Reasons for too high watercontent of the hydraulic fluid can be:

Entry of aqueous cutting coolant.

Penetrated rainwater or cleaning water.

Condensation due to temperature variations and/or fluctuating oil volume in the oilreservoir.


Hydraulic fluid and accessories (3)19


Leaky coolers.

Missed regular drain of deposited water from the hydraulic oil reservoir.

1.3 AIR BUBBLES IN THE HYDRAULIC FLUID

Air bubbles contained in the oil can lead to troublesome noises (cavitation), movementmalfunctions and plant damage.

The following influences promote the formation and the stay of air bubbles in the oil:

Wrongly selected or polluted hydraulic fluid.

Too small or wrongly designed hydraulic oil reservoir (too little oil residence time,turbulence of the flowing-back and again sucked-on oil).

Leaks on low pressure zones (e.g. suction line, pump, throttle valves).

Formation of air bubbles in case of pressure drop (e.g. by sharp pipe bends, hosebends).

Insufficient plant ventilation (at first putting into operation, after repairs).

Too fine-mesh or clogged screens or filters in front of suction line.

1.4 SURFACE FOAM

Surface foam can entail the suction of foam through the pump or foam escape from thereservoir. The following influences promote the excessive formation of surface foam:

Excessive oil soiling (Dirt, water, oil ageing products, preservatives, solvents andothers.).

Wrong reservoir design.

Too high circulation numbers.

1.5 OVERHEATING OF THE HYDRAULIC OIL

The oil temperature in the hydraulic oil reservoir should not exceed 60°C at stationary plantsand 70°C at movable plants. Too high oil temperatures shorten the life of the oil filling as wellas of seals and hoses. They promote the formation of residues and thus valve bondings andfilter obstructions. They decrease the throughput rate and the efficiency and increase the wear.

As reasons of excessive hydraulic fluid temperatures are possible:

Pump with too large volume throughput (excessive throttling).

Too small or wrongly designed hydraulic oil reservoir.

Missing, too small, wrongly set, soiled or defective cooler.

Wrong viscosity of the hydraulic fluid (too high or too low).

Wrongly dimensioned pipes (too small diameter, too small bending radii).

Pressure relief valve set wrongly, soiled or defective.

Heat exposure from outside (solar radiation, furnaces, high room temperature).

1.6 EXCESSIVELY HIGH EXTERNAL LEAKAGE LOSSES

Leakage losses frequently cause higher refilling quantities than the required oil changes.Leakage losses are expensive: e.g. 50 leakage places can cause with one drop every 5seconds a yearly loss of approx. 10 000 litres hydraulic fluid.

Hydraulic fluid and accessories (3) Creation date: 18.03.200320 Printing date: 20.3.2003


Frequent reasons for running-out waste oil are:

Leaky piping connections and components.

Insufficient plant inspection and maintenance.

Defective cylinder and shaft seals.

Badly accessible piping connections (more difficult tracing of leakages).

Defective hoses.

Missing sealing protection (e.g. stripper, bellows, covering plates) at the reaction of dirtor metal chips.

1.7 MONITORING OF HYDRAULIC FLUIDS AND EQUIPMENT (INSPECTION)

All deficiencies or peculiarities striking the operating personnel at operation must either beeliminated immediately or be signalled to the competent department.Among these count:

Too low fluid level in the oil reservoir.

Hydraulic fluid colouring (milky, dark, foamy).

External leakages.

Noises, vibrations.

Loose device fixings or piping connections (only tighten at pressure-relieved plant!).

Function malfunctions, e.g. pressure or material throughput decrease.

Filter soiling (observe filter soiling display!).

External plant soiling or damage.

Rust formation inside the hydraulic oil reservoir.

1.8 CARE OF HYDRAULIC FLUIDS AND EQUIPMENT (MAINTENANCE)

If not separate manufacturer instructions exist, for hydraulic fluids on mineral oil basis theexecution of the following maintenance work is recommended:

Refill missing hydraulic fluid (current).

Drain deposited water permanently from oil reservoir.

Cleaning and/or exchange of the oil and air filter according to regulation of the plantmanufacturer.

Refill pressure accumulator on the gas side after examination if required (every threemonths).

Hydraulic fluid change (according to regulation; approx. every 1000 - 5000 hours ofoperation at not monitored hydraulic fluid fillings).

Exchange of seals and hoses (according to regulation).

Grease hand lubricating points according to regulation.

Cleaning of oil reservoirs at each oil change.

Additional care of oil filling by partial flow filtering with movable filter device and/or byseparation (yearly).




2 OIL CONTAINER

2.1 TASK OF THE OIL RESERVOIR

To each hydraulic plant belongs an oil reservoir, which has to fulfill manifold tasks. These arein detail:

Reception of the oil stockThe reservoir should be able to receive the whole oil volume existing in the system. In additionto the nominal volume an air cushion of 10 ... 15% is provided, which can receive variations ofthe oil level and surface foam. The pump sucks on from the oil reservoir and the oil gets via thereturn pipe from the consumer back to the tank.

Carrying-off of heat due to energy lossesThe losses in efficiency in a hydraulic plant lead to the heating-up of the oil. This heat is to abig part radiated via the areas of the oil reservoir, must possibly be provided with cooling finsand be installed at a favourable site.

Depositing of impuritiesAgeing products and smalles impurities, which are not settled out via the filter, deposit on thefloor of the reservoir.

Elimination of airAir bubbles in foamed oil lead to troublesome noise formations and damage, in particular in thepump (cavitation). They arise when at low pressure the saturation for solved air is exceededor get into the system via leaky points in the suction line. Turbulences in the return line alsolead to foam formation. As another disadvantage for too high air shares in the oil is increasedcompressibility and thus decreased stroke accuracy must be mentioned. Further, an increasedoil temperature results by compression of the air bubbles. Unsolved air is settled out in the oilreservoir so that an as large as possible air area and long residence dwell time of the oil mustbe striven at. Suction and return area are separated by the relaxation plates in order to keepsurface foam away from the suction connection and in order to prevent that the back-flowingoil is immediately sucked on again.

Hint!When air is compressed with oil, from 140 bar oil pressure the so-called Diesel effectappears.

Symbol

Level variation

ReturnAir cushion

Ballcock with monitoring limit switch

Pressure line



Here the existing oxygen is burnt. It arises a short explosion at which not only the seals, pipe-lines and hoses are damaged, but even finest particles are torn from the metal surface. Thisincreases the wear of the seals again.

Separation of condensationDue to temperature fluctuations in the reservoir condensation water is formed, which isdissolved in the oil only to a little extent. From undissolved water together with the oil anemulsion arises, or it is separated. It is collected on the deepest point of the reservoir.

2.2 HYDRAULIC OIL CHANGE

Attention!

When changing the lubricant make the whole hydraulic oil filling mustbe exchanged! If a refilling with another lubricant than the employed one should be nec-essary, contact must be established with the supplier of the refillingregarding miscibility!

In the normal case a hydraulic oil change must be made after approx. 5000 - 6000 hours ofoperation.Due to corresponding circumstances an oil change can already be required earlier, however!Therefore we recommend to have the used oil state checked by the hydraulic oil supplier inintervals of approx. six months and/or 3000 operating hours, and to make a hydraulic oilchange according to his recommendation!

Change process:

Dismount the filling and venting filter

Suck off used oil by means of suction pump and drain the re maining oil through the oildrain plug (below on the oil tank

Dismount cleaning cover on the oil reservoir

Clean oil reservoir walls and floor from mud residues (e.g. with Diesel oil)

Screw in oil drain plug

Mount cleaning cover on the oil reservoir

ContactlessLimit switch

Suction line with shut-off valve (ballcock)

Relaxation plates

Return Cleaning cover




Mounting filling filter

Fill oil reservoir with corresponding filling unit with downstream fine filter (max. 10µmabsolute). Only use clean branded oil. The oil level must reach up to the upper third ofthe sight glass.

Unscrew oil reservoir-filling screw coupling

Afterwards the hydraulic pumps must be vented.

3 ADDITIONAL DEVICES FOR THE TANK

3.1 FILLING AND VENTING FILTER

The filling and venting filter has two tasks:

as filling filter: When filling in the fluid into the reservoir the filter prevents that coarse dirtparticles get into the reservoir and hence into the system. Therefore the filling-in of thehydraulic fluid should basically be made via a filling filter.

as venting filter: With varying liquid level, e.g. due to different consumers, an aircompensation must occur, the air flowing into the reservoir being filtered.

Thermosensor

Cleaning coverOil level display with built-in oil level switch

Contactless limit switch

Suction line with shut-off valve (ballcock)

Filling and venting filter



3.2 OIL LEVEL SWITCH

The oil level switch serves the monitoring of the level of liquid in a reservoir. With it the min.liquid height can be monitored.When the measuring point is not reached, the switch gives a signal to the control unit and thepump motor is switched off.

3.3 OIL LEVEL CONTROL

The oil level can be controlled via a sight glass, which possesses a min./max. marking.

Siev

Cover with air filter

v




3.4 THERMOSENSOR

For monitoring the respective operating temperature (in connection with a pre-heating circuitor excessive temperature switching-off) the thermocouple is used.

3.5 SUCTION LINE WITH BALL VALVE AND ELECTRIC MONITORING

The ball valve in the suction pipe is monitored with a contactless limit switch. When the ballvalve is closed, the motor switches off. This prevents the oil turbulences and reducedpressures in the suction pipe. Air dissolved in oil is not separated and/or air does not get intothe hydraulic system via the suction side.

4 OIL PREHEATING, COOLING

4.1 TASK

As is generally known, the viscosity of the oil strongly depends on its temperature and shall notexceed or remain under certain limits in order to guarantee a trouble-free operation of theplant. Too high viscosity at low temperatures leads to cavitation damage on pumps andincreased frictional losses on restrictors and in pipings. Too low viscosity at high temperaturescauses increased leakage losses and decreases the strength of the lubricating film betweengliding parts and thus the wear protection. Further, increased temperatures entail prematureageing of the oil and destruction of elastic seals.Variable viscosity values during the operation of a machine decrease the accuracy of theadvance speeds and impair the work result of a machine.It is the task of preheating and cooling equipment to keep the temperature values of thehydraulic fluid within the allowed tolerances.

t°

-+



4.2 PREHEATING

A preheating is only required when a machine is started at low ambient temperatures afterlonger standstill and very exact parts shall be produced immediately after the start. At thepreheating the pump conveys against a pressure relief valve and heats up the oil very fast dueto frictional losses until it finally reaches its ideal operation viscosity.

4.3 COOLING

In a hydraulic plant arise power losses (at the energy conversion, transport and control), whichlead to a heating-up of the pressure medium. This heat is given off to the environment via theoil reservoir, pipings and other components by radiation or convection. So the oil temperaturerises during the start-up phase and finally reaches a constant steady-state temperature. Thisis the higher, the lower the cooling capacity of the plant is. If the cooling capacity of oilreservoirs, pipings etc. is not sufficient, an additional chiller must be installed. Here air- andwater-cooled heat exchangers are used.

4.3.1 SHELL-AND-TUBE EXCHANGERS

This is streamed through by the hydraulic fluid to be cooled as well as by the cooling water.The separation of the two media occurs via heat-conducting cooling pipe coils or lamellae.Via oil-water cooler bigger power/energy losses can be carried off. The supply with coolingwater conditions a corresponding installation (cooling tower) or is connected with high runningcosts (tap water).

Mode of action:The cooling water streams through the water inlet-pipe connection into the oil cooler, flowsthrough the U cooling pipes and streams out again through the water outlet-pipe connection.The oil to be cooled goes into the cooler radially at the oil filler inlet neck, flows through thepipe gaps of the bundle of pipes and is forced to a large cross-flow by the baffle plates. Themachine control unit closed loop controls via a cooling water valve depending on oiltemperature the duration of connection of the cooling water.If the cooling capacity decreases, a soiling of the cooling surface of the water is the reason.

Water connec-tion

Internal pipes Emptying, vent-ing

Seals

Oil connection

Jacket tube




Cleaning possibilities:

Rinse away existing deposits with high water speed

With stone and/or lime solvent dissolve and rinse away existing deposits

Screw off both covers on the front side and carry out mechanical cleaning of the internalpipes

At all three above mentioned cleaning variants the oil cooler must be rinsed throughthoroughly, be freed from impurities and be assembled again if required provided with newseals!

4.3.2 PLATE HEAT EXCHANGERS

4.3.2 Plate heat exchangers

The plate heat exchangers consist of up to 200 profiled plates of stainless steel. The profilingdirection changes from plate to plate so that on the profile backs a large number of connectionpoints arises. When soldering the plates together, also the contact points connect themselvesand form so an extremely stable platen package whose almost whole surface is available asexchange area.

The complex geometry cares for a turbulent flow, which leads to a very high heat transfercoefficient. In case of turbulent flow with in principle free channels and smooth surface not theextreme speed reduction and as a result not the danger of formations of deposits arises either.

Oil inlet Oil outlet

Water inletWater outlet



At the laminar flow often the problem arises that in the centre of a pipe the higher speedprevails. So the flow rate becomes less the nearer one comes to the pipe surface. This canlead to extremely low speeds on the surface and as a result favour the deposit on the surface.

Cleaning:A safe sign for the fact that the deposit has arisen, is a bigger temperature difference betweeninlet and outlet of the heat exchanger, the deposits on the surface restricting the heat transfercapacity. Another possibility for detecting deposits is the measurement of the pressure loss viathe chiller. In both cases of course the specified throughput rates of water and oil must also bemeasured.By flushing back with water one can remove almost all deposits. When hard deposits orhardness precipitations have arisen, a slightly acid solution (5% phosphoric acid) shouldcirculate several times against the water flow direction.

Attention!

After an acid cure the heat exchanger must be rinsed with water thor-oughly and sufficiently.

4.4 OIL TEMPERATURE CONTROL

Screen lines:

The oil temperature shall always be approx. 40 - 45°C. When the oil temperature is under theset minimum value, the oil preheating program starts after switching on the motor, and noautomatic cycle start is possible (message: OIL TEMPERATURE TOO LOW). When the maximum value is exceeded, the cycle is interrupted and alarm is displayed(message: OIL TEMPERATURE TOO HIGH).

Oil temp. Set value = Act.val =

40 °C39°C

Minimum temperature 30°CMaximum temperature 55°C

Turbulent flow Laminar flow




5 FILTER

5.1 TASK OF THE FILTERS

In oil-hydraulic plants large volume throughputs flow through extremely small gaps under highpressures. This entails that this plant is considerably more sensitive towards impuritiescontained in the oil, above all towards solid foreign substances than other machine types.Previous experience has shown that over half of the premature failures appearing in oil-hydraulic plants is due to polluted hydraulic fluid. It is the task of the hydraulic filter to reducethis pollution to an allowed measure regarding size and concentration of the contained dirtparticles in order to protect thus the components against excessive wear.

5.2 IMPACT OF THE SOILING

The dirt particles themselves are e.g. dust, metal and rust particles, they promote the abrasionwear of the metal parts and seals moved against each other in the hydraulic components.Affected by the soiling are e.g. the bearings, wings, tooth flanks and pistons of the hydraulicpumps and motors as well as the pistons, piston rods and bushes of the working cylinders. Thewear of the sliding surfaces increases the fits and entails increased internal leakage,decreased throughput rate and increased temperatures. Emerying foreign substances canmoreover cause metal denudations on valves, e.g. on leading edges, seatings anddiaphragms. Also non-emerying, solid foreign substances, such as seal abrasion, filterparticles, textile fibres and small colour plates can lead to function malfunctions by the additionof channels, gaps, pipings and filters as well as by the jamming of valves.While relatively big solid particles (50 µm) often cause sudden machine failures shortly afterthe first putting into operation, impurities of smaller particle sizes (10 µm) generally lead toslow wear with slow damage development.The harmful influence of solid impurities depends on the hardness, size and concentration ofthe particles as well as on the dirt sensitivity of the individual components. To wear lead inparticular the solid particles whose size corresponds approximately to the fit of the parts glidingon each other. Because of their tight fits and high stress of the lubricating films modernhydraulic pumps and motors designed for high pressures are more dirt-sensitive than deviceswith smaller power density.

5.3 SUCTION FILTER

The plant is provided with a wire strainer on the suction side in order to protect the hydraulicpump against damage by coarse impurities. Fine pored filters are more problematic as the maximum low pressure demanded by mostpumps in the suction pipe of 0.7 bar (absolute) can herewith only be reached hard. This is inparticular valid at cold oil and soiled suction filter. The suction filter is built in in the tank under the oil level and is provided with a valve, which isclosed before the removal by screwing off the cover in order to prevent that oil streams afterfrom the tank.



The suction filter is equipped with a low-pressure switch. When the low-pressure switch reacts,the message ’’CHECK SUCTION FILTER’’ is displayed and the pump is switched offimmediately.At the reaction error message the suction filter must be removed and cleaned! Procedure:

Screw off filter cover and pull out filter element. The valve is closed during screwing-off,and thus a flowing-out of the hydraulic oil is prevented

The filter element is dipped into clean cleaning fluid and swivelled in order that the dirtdeposited on the surface comes loose

Blow through the filter element from inside to outside with compressed air until thesurface of the element does not show any dirt any longer and/or the cleaning fluidremains clean

Before filter installation check seals and replace them if required!

Attention!

At machine with fixed displacement pump: Fixed displacement pumpmust be ventilated after the filter installation!

5.4 LOW-PRESSURE FILTER

Spring

Valve

Flat sealing ON

CoverOFF

Filter element ON




5.4.1 GENERAL

The low-pressure filter is built in as component in the bypass - hydraulic oil - filter system andequipped with a mechanical-electric soiling indicator.The mechanical soiling indicator is a red knob on the upper side of the filter, which jumps outin case of too high pressure difference (filter soiled) (approx. 4 mm).By switching off the pump motor the mechanical indicator is not reset, the red knob must bepressed in again manually!The electric soiling indicator sends a signal to the machine control unit, it appears the errormessage ’’153 CHECK FILTER’’ on the screen. The machine finishes the current cycle andstops, the mold protection lamp is set. In further sequence the motor is switched off delayedand the heating is reduced delayed.

5.4.2 MAINTENANCE INSTRUCTIONS - LOW-PRESSURE FILTER

The filter element must be exchanged when the mechanical-electric contamination displayreacts. When the red knob jumps out when starting in the cold state, it should only be pressedin again after reaching the operating temperature, when it jumps out again, the screw-oncartridge must be changed.

Change of the screw-on cartridge:

Screw off screw-on cartridge by means of ribbon key by turning to the left

Check whether the order number on the new screw-on cartridge is identical with theorder number on the type plate

Oil the seal of the screw-on cartridge slightly

Screw the screw-on cartridge on according to printed-on in structions

Press in red knob

Figure low-pressure filter small machines

1 Screw-on cartridge2 Gasket3 Mechanical soiling indicator (red knob)4 Electric soiling indicator



Figure low-pressure filter large machines

5.4.3 PRESSURE FILTER

High-pressure filters are built in immediately after the pump and equipped with a mechanicalsoiling indicator and/or with electric monitoring (error message: ’’HIGH-PRESSUREFILTER’’). When the injection molding machine is equipped with SERVOVALVE, in the controloil circuit also a small pressure filter with electric monitoring is built in.The mechanical soiling indicator is a red knob on the upper side of the filter, which jumps outin case of too high differential pressure (filter soiled). When switching off the pump motor themechanical indicator remains and must be pressed in again manually!The filter element of the high-pressure filter must be changed when the mechanical and/orelectric monitoring reacts at an oil temperature of approx. 40°C.

1 Electric soiling indicator2 Gasket3 Manometer




Filter element change:

Screw off filter hood by turning to the left and clean it with a suitable cleaning agent (e.g.petroleum ether, petroleum)

Take off the filter element downwards by slight to and fro movement

Check O-ring and thrust ring in the filter hood for damage (Replace if required)

Check whether the order number on the spare element is identical with the ordernumber on the type plate of the filter

Open the plastic cover, push the element over the reception piece in the filter head anddraw off the plastic cover

Screw the filter hood into the filter head up to stop and turn out filter hood again by 1/8to 1/2 revolution

Attention!

A cleaning of the filter elements is not possible! New filter elementsmust be built in! Take spare filter elements in stock!

6 HYDRAULIC ACCUMULATORS

Filter element

Soiling indicator

Filter hood

By-pass valve



6.1 TASK

Hydraulic accumulators offer manifold application possibilities:

Energy storage for saving pump drive power at plants with intermittent operation.

Energy reserve for emergency cases, e.g. in case of failure of the hydraulic pump.

Compensation of leakage losses

Shock and vibration damping in case of periodic vibrations.

Volume compensation at pressure and temperature changes.

Resilience element at vehicles.

While in the pneumatics the medium air can be compressed immediately for the storage ofenergy, a hydraulic fluid is hardly compressible. In order to be able to store it under pressurenevertheless, one uses a neutral gas, in this case nitrogen. This is compressed in a pressure reservoir by the hydraulic fluid and relaxes in case of needunder emission of fluid. In order that the gas does not mix with the fluid (foam), the pressurereservoir is divided into two chambers by an elastic partition wall.

6.2 COMPONENTS AND MODE OF ACTION

6.2.1 COMPONENTS BLADDER ACCUMULATOR

The elastic partition wall between hydraulic fluid and compressible medium (nitrogen) forms abladder, which is fixed in the pressure reservoir by means of the vulcanised-in gas valve bodyand can be built in and removed by the reservoir opening on the fluid valve. The fluid valve has




the task to close the inlet opening with completely extended accumulator bladder and so toprevent that the bladder is pressed into this opening. A damping equipment protects the valveagainst shocks in case of fast opening.

6.2.2 COMPONENTS DIAPHRAGM ACCUMULATOR

As elastic partition wall between hydraulic fluid and nitrogen serves a diaphragm which isclamped in the pressure reservoir. In the diaphragm bottom a closing knob is fixed, which ispressed into the opening in the pretension state with completely extended diaphragm.On the gas side the locking screw allows the controlling of the filling pressure and the refillingof the accumulator by means of a filling and test device

6.2.3 MODE OF ACTION

When liquid is pressed into the accumulator, the gas volume decreases under simultaneouspressure increase. When vice versa liquid is taken from the accumulator, the gas cushionexpands until gas pressure and liquid pressure are compensated again. When liquid ispressed into the accumulator, the gas volume decreases under simultaneous pressureincrease. When vice versa liquid is taken from the accumulator, the gas cushion expands untilgas pressure and liquid pressure are compensated again.

Steel reservoirBlad-

NutGas

Gas valve insertGasket

Locking capValve cap

Rubber ring

Groove nut

Liquid valve

Damping bush Vent screw

diskGuard ring

Gasket

Thrust ring



6.2.4 SAFETY HINTS FOR PRESSURE ACCUMULATOR EQUIPMENT

Attention!

After putting out of operation and/or before maintenance and repairwork on the injection moulding machine one must ensure a pressure-less state of the pressure accumulator equipment by all means.Check of the pressureless state:(Pay attention to hydraulic scheme!)- On the manometer(marked by means of pressure accumulator symbol)Pressure shut-off lever on the manometer must be in open position.

Hint!Pressure shut-off lever on the manometer - not valid for free-standing accu stations

Attention!

- On the screen of the microcomputerSelect corresponding screen page.

Basically the pressure accumulator equipment is discharged automatically when putting themachine out of operation by switching off the machine main switch.(Observe discharging time!)

As additional safety precaution the following measures must be taken!

SAFETY AND SHUT-OFF BLOCK

Close main stop cock (lever(Because of that the hydraulic pressure pipe from the pump must be interrupted onthe safety/shut-off block!)

Open relief valve (connection to the hydraulic oil container)

ACCU BLOCK

open the relief valve

Hint!Not valid for free-standing accu stations.

Attention!

CHECK: The accumulator pressure on the manometer selector switch/pressure gauge must be 0 (zero) bar!




Hint!Observe in case of required maintenance and repair work on the PRESSURE ACCUMULA-TOR EQUIPMENT:- The access for the assembly of the filling and checking device can occur by the opening of acover in the area of the machine frame on the injection unit.- All maintenance and repair work required moreover may only be carried out by the manufac-turer works ENGEL or on consultation with the manufacturer works ENGEL.

Attention!

TO FILL THE ACCUMULATOR BLADDER USE NITROGEN EXCLU-SIVELY.IN NO CASE USE OXYGEN.DANGER OF EXPLOSION!

7 PRESSURE MEASUREMENT CONTROL EQUIPMENT

7.1 MANOMETER

Hydraulic pressures can be checked with the respective pressure measurement controlequipment, but the manometer shut-off valve should only be opened for pressure control!



7.2 PRESSURE TRANSDUCER

Depending on machine type several pressure transducers are used

In the standard case a pressure transducer for a pressure range up to 414 bar is used. It issupplied with a voltage of 24 V and delivers an output signal of 24.17 mV/bar.A hydraulic pressure transducer can be adjusted or damaged by pressure peaks, which canarise by defective or badly adjusted valves. The displays of the pressure transducers on thescreen shall always be compared with a test manometer in case of regular maintenance.

Features of the pressure transducer (Dynisco):

Fully welded stainless steel housing resists the roughest conditions and corrosivemedia.

A special diaphragm form guarantees higher accuracy, better reproducibility and higherexcess pressure safety.

Optimized heat treatment of the diaphragms increases the overload characteristics andcontributes to longer life.

Potted electronics, because of that high shock and vibration resistance.

100

200

300

4000

Manometer with glycerine filling

Console for manometer fix-ing is screwed fixed on the unit or equipped with mag-net foot

Manometer-shut-off valve

PU




All pressures are displayed on the screen page ’’Input calibration’’,(user level 8).The pressures are displayed on the screen page ’’Input calibration’’,and ’’Pumpcalibration’’ (user level 8). (GM)



HYDRAULIC PUMPS AND HYDRAULIC MOTORS (4)

Apart from the different types of construction one distinguishes between:

Fixed displacement pumps, fixed displacement motors: The stroke volume cannot bechanged

Variable displacement pumps, variable displacement motors: The stroke volume can bechanged

1 HYDRAULIC PUMPS

Pumps have in the hydraulics the task to produce a stream of liquid (to displace a liquidvolume) and to grant to this the required forces at the same time according to requirements.The pump sucks on liquid from a reservoir and displaces it to the pump outlet. From there theliquid gets into the system via the individual control elements up to the consumer. Theconsumer represents for the liquid a resistance, e.g. a piston pressurized by a load of a liftingcylinder.Corresponding to this resistance in the liquid a pressure builds up which rises so high as it isrequired for overcoming these powers of resistance. The pressure in a hydraulic system is notproduced by the hydraulic pump already from the start, but only builds up. So this occurs as a function of the resistances which oppose the stream of liquid. One couldconsider the liquid column also as liquid connecting rod, to which, as mentioned above, therequired forces are granted by the pump.

2 LOW-PRESSURE PUMP

2.1 VANE-CELL PUMP

The vane-cell pump has a constant displacement volume and is used for the oil filtration.


Hydraulic pumps and hydraulic motors (4)41


2.2 SCREW TYPE PUMP

The spiral pump has a constant displacement volume and is used for the oil filtration. Themaximum pressure is 8 bar.

Suction port in the plate cam

Oil outlet opening in the plate cam

Bushing

Motor flange Pressure release valve

Shaft seal

Rotor

Wing

Inside ring Plate cam

Hydraulic pumps and hydraulic motors (4) Creation date: 18.03.200342 Printing date: 20.3.2003


3 HIGH-PRESSURE PUMPS

3.1 INTERNAL GEAR PUMP

Components:They essentially consist of housing (1), bearing cap (1.1), cover plate (1.2), internal gearedwheel (2), pinion shaft (3), plain bearings (4), axial discs (5) and stop pin (6) as well as of thesegment filler piece (7), which is composed of segment (7.1), segment carrier (7.2) and of thesealing rollers (7.3).

Ball bearing greased by the conveyed fluid

Small production tolerances guarantee a high volumetric efficiency and low noise level

Epicyclic profile of the hydrauli-cally well balanced drive shaft

Employment for the compensa-tion of thermal expansions and for the hydraulic sealing

Maintenance-free seal




Suction and displacement processThe hydrodynamically stored pinion shaft (3) drives the internal geared wheel (2) in the showndirection of rotation. During the rotary movement the volume enlargement occurs on an angleof approx. 180 degrees in the suction area. A reduced pressure arises and fluid flows into thechambers. The sickle shaped segment filler piece (7) separates suction and pressure space.In the pressure space the teeth of the pinion shaft (3) plunge into the tooth space of the internalgeared wheel (2). The fluid is displaced via the pressure channel (P).

Axial compensationThe axial compensation force FA acts in the area of the pressure space and is produced withthe pressure field (8) in the axial discs (5). Because of that the axial longitudinal gaps betweenthe rotating and the fixed parts are extraordinarily small and guarantee an optimum axialsealing of the pressure space.

Radial compensationThe radial compensation force F R acts on segment (7.1) and segment carrier (7.2). The arearatios and the position of the sealing rollers (7.3) between the segment and segment carrierare designed so that a largely leakage gap-free sealing between internal geared wheel (2),segment filler piece (7) and pinion shaft (3) is reached. Spring elements under the sealingrollers (7.3) care for sufficient contact pressure, even at very low pressures.

Hydrodynamical and hydrostatic storageThe forces acting on the pinion shaft (3) are received by hydrodynamically greased plainbearings (4); the forces acting on the internal geared wheel (2) by the hydrostatic bearing (9).

ToothingTheir working length yields little throughput and pressure pulsation; these low pulsation ratescontribute to the low-noise running considerably.



3.2 VARIABLE DISPLACEMENT PUMP

In order to reduce the energy consumption of the automatic injection molding machines,variable displacement pumps are employed. These pumps have the advantage that only thatamount of oil is conveyed which is necessary for the respective operating state. So the pumpscan be adjusted in their throughput from 0 to maximum and adapt themselves to the operatingconditions as a function of the operating pressure.

Performance balance:These diagrams show the difference between a fixed and a variable displacement pumpregarding the power/energy loss with 50% given speed and 50% needed pressure of aconsumer.

3.3 RADIAL PISTON PUMP

The radial piston pump is an internally pressurized, slide-controlled pump with pistonsarranged radially in the radial arrangement of cylinders, which support themselves via guideshoes in the stroke ring. The adjustment of the volume throughput and reversal of theconveying direction occurs by changing the eccentricity of the stoke ring by means of twoadjusting pistons. The drive torque is transmitted from the shaft stored in the cover via a cross-type disc couplingto the radial arrangement of cylinders free from transverse force. This rotates on a controlpivot, which on its part it shrinked into the housing.

100%

50%

0

Q max.

Power/energy

FIXED DISPLACE- VARIABLE DIS-

Power/energy loss at pressure-throughput closed loop control

P

Needed performance

100%

50%

0

Q max.

Needed performance

100% P100% P P

is omitted in case of electrohydraulic adjustment

P = pressure gradient on the proportional




Plunger and guide shoes are connected with each other via a ball-and-socket joint and arecaptivated by a ring. The guide shoes are led through two overlapping hold-back rings in thelifting ring and are pressed against the lifting ring in the operation by centrifugal force and oilpressure.

The change of the eccentricity of the stroke ring occurs by means of the hydraulic adjustingpistons 1 and 2. These have an aspect ratio of 2:1 and are arranged perpendicularly to theconveying direction. The smaller adjusting piston 2 is pressurized with the high pressure permanently and pressesthe stroke ring against the larger adjusting piston 1, which is blocked by the control valvedepending on state of operation, is pressurized or relieved.Correspondingly the stroke ring is retained or moves in the one or other direction. Here it rollsoff in the housing.At the pumps with one conveying direction the control pressure is taken directly from the high-pressure channel in the control tenon. Via a bore it gets into a snap ring groove at theperiphery of the control tenon, from there into a cast pocket of the housing and over furthercontrol bores to the adjusting plunger 2 and to the open loop and/or closed loop control valve.The conveying direction of the pump depends on the range of adjustment of the stroke ringbesides the drive direction of rotation. At pumps with one-sided conveying direction only onerange of adjustment is utilized and the displacement volume 0 is determined by a fixed stop ofthe stroke ring.The waste oil resulting on the different sealing gaps is carried off from the housing via aseparate waste oil connection. The waste oil line is carried off to the tank pressureless (p max= 2 bar absolute) as the housing pressure charges the shaft seal and the connection betweenpiston and guide shoe.

Suction sideRadial arrange- Adjusting piston PistonAdjusting pis-

Stroke ring Guide shoesControl valve Leakage oil connec-Pressure



3.3.1 PRESSURE AND THROUGHPUT CONTROLLER

The task of a pressure-throughput controller is to adapt the throughput of a variabledisplacement pump automatically to the real demand of one or several consumers and toprevent a volume throughput excess. This throughput is determined by flow control valves.The controller shall adapt the pump pressure to the consumer pressure at the same time andlimit it when reaching a set pressure limitation.

In the state of rest a spring on the rear side of the large adjusting piston presses the stroke ringon maximum volume throughput, through which the variable displacement pump conveysmaximum volume when switching on the pump motor. The pump pressure gets via a control line to the small adjusting piston as well as via the controlvalve to the large adjusting piston. The same pressure on both adjusting pistons means furthermaximum throughput. Inside the control valve the pressure gets through a bore hole in the piston on its lower frontside. The pump pressure now rises so far until the piston of the control valve relieves the largeadjusting piston to the tank against the set spring power (approx. 16 bar). The volumethroughput of the pump goes in direction 0 and only conveys the waste oil losses. The throughput of the pump is switched to the consumer when actuating a movement by aproportional throttle valve. The pump pressure decreases, the control valve pressurizes by thespring the large adjusting piston with pump pressure, through which the conveying volume ofthe pump is increased. The pressure after the proportional throttle valve (consumer pressure)acts via a control line (externally) with built-in nozzle into the spring room of the control valveand is added to the set spring resistance. The large adjusting plunger is only relieved again when on the control valve plunger state ofequilibrium prevails (consumer pressure + spring power = pump pressure). A pressuredifference of approx. 16bar appears via the proportional throttle valve. So throttle valve andadjusting plunger work together like throttle and pressure regulator of a flow control valve.

Proportional throttle valve

Nozzle for control oil limitation

Adjusting screw for spring, determines ∆P on the proportional throttle valve

Proportional pressure relief valve

∆P = 16 bar




In contrast to the flow control valve on the control edges of the pressure regulator not thevolume throughput is influenced directly, but like at pressure controlled variable displacementpumps they control the eccentricity of the lifting ring and hence the throughput of the pump. Adecrease of the cross-section on the proportional throttle results e.g. in an increase of thepressure difference, which presses the solenoid of the control valve against the spring so thatthe large adjusting plunger 1 is relieved and the lifting ring of the pump wanders to the neutralmiddle. The control movement is finished when the pressure difference of approx. 16 bar determinedon the control spring arises again. The corresponding reverse is valid when increasing thecross-section on the proportional throttle.In the control conduit to the spring room still a proportional pressure relief valve is arranged sothat the effect of a pilot operated pressure controller arises and the pump limits when reachingan adjustable pressure.

3.3.2 START-UP OF THE RADIAL PISTON VARIABLE DISPLACEMENT PUMP

Before the first switching-on the housing of the radial piston pump must be filled with themedium to be conveyed via the leakage oil connection. Check direction of rotation of the drivemotor immediately! Until venting the hydraulic plant it should be run with low pressure.

Attention!

The oil temperature in the tank must not exceed the temperature of thepump by more than 25°C. When this is the case, until the heating-up thepump may only be switched on in short intervals of approx. 1-2 sec-onds.

3.3.3 RADIAL PISTON PUMP WITH ELECTROHYDRAULIC ADJUSTMENT

The radial piston pump is equipped with three additional components in order to fulfillthe following functions:

Position closed loop control for the lifting ring of the pump. This component includes aposition measuring system, a highly dynamic control valve and an electronic amplifier.

Electric pressure closed loop control. When reaching the set pressure set value, thevolume throughput is reset so far that the given pressure is maintained.

Electric circuit for the leakage current compensation. With it the pressure-dependentvolumetric losses of the pump are largely compensated.



Advantages as compared with the solution with combined pressure and throughputcontroller:

Shorter regulating times at low system pressure, especially when the adjustment issupplied with foreign pressure. With this higher dynamics the pump follows the given setvalue profiles more exactly.

Linear pressure characteristic line up to low pressure setting values. Thus also in lowpressure ranges high accuracies of the set values are achieved. The used pressuresensor reaches a high reproducibility and long-term constancy.

At flow controlled systems the power/energy loss is proportional to the throughput (Pv ~Dr.Q). These system-conditioned losses are omitted here, i.e. the system efficiencybecomes better.

3.4 AXIAL PISTON PUMP (TAPERED WASHER PUMP WITH ADJUSTABLE VOLUME THROUGHPUT)

Axial piston pumps and motors are displacement machines, in which the pistons are arrangedin parallel to the axis of rotation of a cylinder drum. The conversion of the drive rotarymovement into a piston stroke movement occurs according to different basic principles.At the tapered washer pump the cylinder drum is driven whereby the pistons led in it also getin rotation. In axial direction the movement of the pistons is determined by a tapered washerstored in the housing, which is swivelled around the perpendicular line of the drive axis. The displacement volume changes with this tilting angle. During the suction phase the pistonsmove outwards and are kept against the tapered washer via a retaining equipment, pressedby this inwards during the pressure phase.

Electrohydraulic adjustmentSet value Q Valve amplifier




Principle of a tapered washer pump

The rotating delivery plungers move on an elliptical orbit towards the captive C-washer.Friction is mastered by guide shoes or thrust bearings. The rectification of the individualplunger throughputs and/or the assignment to a pressure and suction connection occurs via apiston port. This is arranged in a fixed control plate, against which the cylinder drum rotates with its freeface. This variable displacement pump is suitable for a maximum pressure of 250 bar and canbe employed for pressure and throughput control.

4 HYDRAULIC MOTORS

4.1 ANNULAR GEAR MOTOR

The internally toothed motors show some system-conditioned advantages as compared withthe externally toothed ones. So the mesh of tooth is considerably longer, through which abetter sealing effect results. The irregularity of the absorption volume is less. Thiscircumstance contributes to the decrease of the running noise of the motor.

Captive C-washer small adjusting pis-Cylinder drum (rotates)

safety valve

large adjusting pistonGuide shoes

Conveying pis-

Control valve (DP)



A special construction of the teeth guarantees the sealing between annular gear and internaltoothed disk. Due to planetary movement of the inside wheel in the fixed outside wheel a highabsorption volume of the motor per revolution is given, which allows high driving torques withcompact method of construction.

In order to reach a rotation of the toothed disk, the cells which increase their volume at therotation are pressurized. The cells which decrease their volume at the rotation must beswitched on tank. This control occurs via the drive shaft, on which corresponding grooves areworked in.Per 1/6 revolution or a planetary movement of the toothed disk each cell is switched once onpressure and once on tank.At the exchange of the radial packing ring in the case of a leakage it must be paid attention tothat the motor shaft is not pulled out as the function and direction of rotation is influenced by awrong installation in the toothing of the cardan shaft.In view of a correct direction of rotation the toothed wheel set, e.g. at the Danfoss, OMR motor,must be arranged so that a line thought through two diametrically opposed tooth crownsstands by 15° turned away from the groove of the motor shaft.

Zero position 1/14 Shaft revolution 1/7 Shaft revolution

15°




4.2 GEAR FOR INTERCONNECTING TWO DANFOSS HYDRAULIC MOTORS

Hint!When hydraulic motors are mounted with different torque, the stronger one must be mounteddirectly on the screw drive.

OIL FILLING IN THE GEAR: 2.3lOMV BLS 90 or.CASTROL LSX 90 or.SHELL 90 LS

Screw drive Gear Hydraulic motors

approximate position from the oil sight



4.3 RADIAL PISTON HYDRAULIC MOTOR

ComponentsThe main components are:Housing (1), eccentric shaft (2), cover (3), control housing (4), rolling bearing (5), cylinder (6),piston (7) and control (8.1; 8.2; 8.3).

Inlet and return of the operation mediumThe operation medium is supplied to the motor or carried off via the connections A or B. Viathe control unit and the channels (D) in the housing (1) the cylinder rooms (E) are filled oremptied.

Driving gear; torque productionCylinder and piston support themselves on spherical areas on the eccentric shaft and on thecover. Because of that piston and cylinder can align themselves free from transverse forcesduring the rotary movement of the shaft. Together with a hydrostatic relief on piston andcylinder this causes minimum friction and a very high efficiency. The pressure in the cylinderspaces (E) acts directly on the eccentric shaft. Of the 5 cylinders 2 or 3 each are connected with the inlet side and/or with the outlet side.

control unitThe control unit consists of the plate cam (8.1) and of the diversion valve (8.2). While the platecam is connected fixed with the housing via pins, the diversion valve turns with the samespeed as the eccentric shaft. Bores in the diversion valve are the connection to the plate camand to the piston spaces. The reaction ring (8.3) acts in connection with the compressionspring and the system pressure play-adjusting. This causes a very high heat shock resistanceand constant performance values over the whole life.

LeakagesThe few leakages appearing on piston and control unit in the housing F (1) must be carried offvia the leakage connection (C).




HYDRAULIC VALVES (5)

1 DIRECTIONAL VALVES

1.1 TASK

The task of the directional valves is to shut off or unblock different hydraulic pipings againsteach other and to make changing piping linkages permanently. In this way the direction ofaction of pressures and volume throughputs is influenced and so the consumer (cylinder orhydraulic motor) is controlled regarding start, stop and moving direction.

1.2 GRAPHICAL SYMBOL AND DESIGNATION

1.2.1 SWITCH POSITION AND CONNECTIONS

Of special importance is the number of the connections and of the switch positions of adirectional valve. This is put in front at the designation. Each switch position is represented bya square. Arrows and strokes within a square make the linkage between the connections clear. Thewhole graphical symbol consists of several squares set in a row. The most simple form of adirectional valve has two connections and two switch positions.


Hydraulic valves (5)55


The effect of the different switch positions becomes clear when one displaces the wholegraphical symbol against the fixed piping connections. The designation of the connections withthe letters P, T, A, B and L occurs on the rectangle allocated to the resting position and/orstarting position.

1.2.2 VARIANTS OF THE FLOW RATE SYMBOLS

The linkage between the individual connections is very manifold corresponding to the practicalrequirements. In the following some examples:

The large number of different flow directions arises by corresponding changes on the controlsolenoid using one and the same housing. By means of some examples this becomes clear:

P

P T

A

P T

BA

A

Number of the con-nections

Number of the switch positions

2/2-Directional

AWork connections (consumer)

B

3/2-Directional

4/3-Directional

P Pressure connection (pump)T Return connection (Tank)L Waste oil

2-Directional valves

3-Directional valves

4-Directional

Hydraulic valves (5) Creation date: 18.03.200356 Printing date: 20.3.2003


1.2.3 ACTUATION

Directional valves are brought in their different switch positions by external alter statements,i.e. actuated. The type of the actuation of the directional valve is also expressed in thegraphical symbol. The most important types of actuation are:

The whole actuation equipment acts on the valve slide pressing. The resetting occurs via aspring or via the actuation of the opposite side.

A B

TP

T A P B T A P B

TP

BA

T

A

P

B

T P BA T A P B

BA

P T

P T

BA

T A P B T A BP

TP

A B

Roller tappet

hydraulic

pneumatic

electromagnetic

pilot operated(electrically con-trolled, hydraulically actuated)

Spring resetting(and electromagnet)

pilot operated(with representation of the spring centirng and control oil supply)

Spring centring(and electromagnets)

manually generally




Mechanical actuation by roller tappet

Electromagnetic actuation

Electro-hydraulic pilot control

When larger valves shall be actuated electrically, with direct actuation the construction volumeof the lifting magnets in proportion to the actual valve would be relatively large. For this reasonone goes over to pilot control here. The actual actuation of the control slide occurshydraulically again. So for electric and pneumatic control a pilot valve is necessary.For this purpose directional valves are used which are flanged on the bottom valve. The workconnections A and B of the pilot valve are in connection with the slide front sides of the mainvalve. The connections P and T are connected alternatively with the control channels X and Yor with the connections P and T of the main valve. One distinguishes between:

Control oil inlet internally P(Own oil control)

Control oil inlet externally X(Foreign oil control) index in order form

Control oil outlet internally T

Control oil outlet externally Y

At pilot oil inlet external the pilot oil required for reversing the control solenoid is applied viaconnection X from a foreign pressure source whereas at internal pilot oil inlet it is taken fromthe pressure connection P of the main valve. The flowing-off pilot oil can alternatively becarried off externally via connection Y or internally into the connection T of the main valve.

The roller is approached by a cam or the like and transmits its movement via a tappet on the valve slide. The tappet is sealed.

The armature of magnet with tappet acts with excited coil on the valve slide. Mostly executions for 24V direct current are used. The magnet takes over the sealing of the valve to the outside whereby the arma-ture room is filled with oil.



2 SHUT-OFF VALVES

2.1 SIMPLE CHECK VALVES

2.1.1 TASK, FORMS OF CONSTRUCTION

Shut-off valves have the task to block a volume throughput in one direction and permit in theopposite direction free flow. Therefore they are also designated as check valves. The shut-offshall be absolutely leak-proof, for which reason these valves are always constructed in seatmethod of construction.As sealing elements balls, cones and valve disks are used. These are opened in non-conducting direction against a relatively weak closing spring. The basic principle follows fromthe graphical symbol.

A B

Thread plug PBall sealing T

Pilot valve

Main valve

a bX T B YPA

ab

Check valve without closing spring

Check valve with closing spring




2.1.2 CONSTRUCTIVE DESIGN

Executions for pipeline installation.

Execution for platen connection

2.1.3 USE OF CHECK VALVES

The use of check valves is very manifold. This show some typical examples.

Ball Cone Disk Cartridge

Sinking load is prevented to drive pump

Flow control valve only effective in one direction (throttle check valve)

Circumvention of soiled filters(Opening pressure 0.5 - 3 bar)



2.1.4 SHUTTLE VALVES

As hydraulic ”OR” element acts the so-called shuttle valve, a check valve with two valve seatsand three connections. It is e.g. used for tapping pressures with changing pressure sides. Itcan also be composed of two normal check valves.

2.2 PILOT CONTROLLED CHECK VALVES

2.2.1 APPLICATION, MODE OF ACTION, GRAPHICAL SYMBOLS

At the pilot controlled check valves the blocking position can be eliminated by opening thevalve cone and as a result the throughput can be unblocked in the direction blocked before.They are employed everywhere there where on the one hand in the state of rest in the blockingdirection a however little movement of a cylinder must be avoided (e.g. descent of a load byappearing waste oil on sliding valves) and on the other hand on instruction movements in thedirection blocked before shall be executed.The opening of the valve cone occurs via a tappet by a hydraulically actuated piston, which ispressurized via the pilot oil connection Z. In the represented application the control pressureis taken from the opposite cylinder piping.In the graphical symbol the pilot control is illustrated by a pilot oil connection Z.

B

Z

A




2.2.2 PILOT CONTROLLED DOUBLE CHECK VALVES

In order to be able to achieve a leak-proof shut-off of a consumer in both movement directions,to both consumer lines a pilot controlled check valve must be allocated whereby the controllines are led in each case on the opposite side. In this way e.g. the displacement of a cylinderby external force influences is prevented as long as the direction-controlling directional valveis in mid-position.The two check valves required for this purpose are summarized in one housing. Thiscombination with a common control plunger is designated as shut-off block. Devices for pipeinstallation and as intermediate plate are available. The latter one is flanged between thedirectional valve and its points of connection.

3 CARTRIDGE TECHNOLOGY)

3.1 GENERAL

The classical hydraulic control with cased components has its fixed place in the modernhydraulics also still today. Demands for more compact and less wage-intensive systems leadto height and longitudinal interlinking as well as to special control blocks, to which the valvesare flanged on directly and in which the piping connections are realized by bores.In order to improve the line density and further factors, such as costs, switching behaviour,noise, efficiency etc. further, one began to dissolve the individual functions of conventionalcontrol instruments (directional, pressure, flow control and shut-off valves) and toaccommodate the individual elements directly in bores of control blocks. Complex valve functions are composed of a relatively small number of basic elements (2-wayinternal valves) and standard pilot valves. So also individual, very powerful controls can berealized, for which so far no sufficently big and low-priced valves of conventional type ofconstruction have been available.

3.2 COMPONENTS

The components of the total system are:

Control block: This forms the housing for the internal valves and includes the connectionchannels between the individual valves among each other as well as to the pilot valves

Built-in valves: Hydraulically controlled seat and sliding valves with two workconnections and one pilot oil connection

for plate connection as intermediate plate (pilot operated)

Control piston



Cover plates: These have at first the task to close the bore of the built-in elements, butalso to make connections to the pilot valves.

Pilot valves: These are smaller directional or pressure valves of conventional type ofconstruction and have the task to control the internal valves. Preferrably valves with astandardized pinhole image NG6 are used.

3.2.1 CONTROL BORES

Depending on the requested valve function the control bores can produce the representedconnections.

A A

B B B

F F FX Y

A

A A A

B B

F FXX X YYY F

B




3.2.2 BUILT-IN VALVES AND THEIR VARIANTS

Seat valve with aspect ratio 1:1,6The valve cone and so the connection A-B is closed in inoperative position by the spring.Depending on construction its force corresponds to an opening pressure in the connection Afrom 0.2 up to 4 bar.The indication of the area ratio refers to the pressure working surfaces with connection A andin the spring space F. This ratio has been fixed for all construction sizes with AA:AF = 1:1.6.Hence in the connection B a pressure working surface AB arises with the factor 0,6.The element is predominantly used for the realization of directional valve functions (opening-closing function).

One variant of this valve is equipped with precision control notches and so enables a softopening and closing.Another variant has a connection bore from the connection B to the spring space and can beused as check valve together with a simple cover plate without control bores.

AF = 1,6

Graphical sym-

AA = 1

AB = 0,6



Seat valve with aspect ratio 1:1

The valve seat has the diameter of the guide with valve body so that an area ratio AA:AF = 1:1arises. The pressure in the connection B has no working surface.This execution is mainly used as main stage of a pilot operated pressure relief valve. For thispurpose a nozzle in the valve cone is required. Nozzle diameter and spring are tuned to eachother.

Slide valve with aspect ratio 1:1

For different valve functions, such as for the main stage of pressure release valves or aspressure balance of flow control valves elements are needed which are opened in the restingposition and gradually close at the displacement against the spring. This demand is fulfilled bya slide valve.Depending on the case of application in the valve slide a nozzle is arranged or the threadedhole is closed by a plug. For controlling especially low pressures the spring on the undersideof the valve slide is used.

A

Fine control notches

Graphical sym-

Bore hole

F

B

A

Graphical sym-

Nozzle

AF = 1,6

AA = 1




3.2.3 COVER PLATES

The cover plates have the task to close the built-in bores of the valves and to make theconnections from the spring room to the pilot valves. The appertaining pilot valve can also bemounted directly on the cover plate. The figure shows some standard executions.In practice frequently several internal valves are closed by a single bigger cover plate. On thisthen also several pilot valves can be arranged. Such plates and/or additional control blocksare also designed individually like the main control block.

Graphical sym-

Mould fixing dia-

for check valve

for remote control

for mountedDirectional valve NG 6

for mountedPressure valve

YXF

YXF

X F

M

M

M

M

A P T

P T



4 DIRECTIONAL VALVE FUNCTIONS

For the representation of the total function of internal valves in connection with the pilot valvessymbols are used which are modelled on the constructive execution of these elements. Thesesymbols are not yet standardized definitely, have already been generally accepted for therepresentation of circuit diagrams, however.

4.1 DIRECTIONAL VALVE WITH INTERNAL VALVES 1:1,6

Internal valves with the aspect ratio 1:1.6 can be actuated by solenoid valves in therepresented ways. The electromagnetic actuation is most frequent in practice, of course alsoother control types are imaginable.

The control oil is often taken off from the inlet of the internal valve. Due to the large area in thespring room the control pressure is always sufficient to close this.When the coil a on the directional valve is activated, the piston moves out, in the case b in.

4.2 SWITCHING TIME INFLUENCE

In order to avoid switching shocks on built-in valves at opening and closing processes as wellas to influence the switching sequence of different built-in valves among each other, themovement of the valve cones is delayed. This simply occurs by the fact that the controlconduits are throttled on. As the representation a) shows, 3 possibilities to arrange adiaphragm result. This delays the movement of the valve1 when closing2 when opening and closing3 when openingAt the arrangement according to 3 it must be paid attention to the fact that the connection T ofthe pilot valve is not loaded over the allowed value. Representation b) shows an arrangementwith a special pilot valve at which connection T is not loaded.




The diaphragms can be accommodated in the flange areas between cover plate and pilotvalve and/or control block. An assembly-friendly solution represents the screw-in throttle in thecover plate.The effect of the switching delay is improved further by special internal valves with precisioncontrol notches.

5 PRESSURE VALVES

5.1 PRESSURE RELIEF VALVES

This valve has primarily the task to limit the pressure in an equipment and so to protect theindividual components and conduits against bursting and overload. Corresponding to this taskone also speaks of the maximum pressure valve or safety valve. This limitation occurs by thefact that the at first closed valve opens when reaching the given pressure and carries off theexcess throughput of the pump to the tank. At this application the pressure relief valve isarranged in the shunt (by-pass).The current Q flowing-off under the pressure p via the pressure relief valve corresponds to apower/energy loss.P = p . QThis power is fed to the hydraulic system from the drive machine and goes over into oilheating-up.

a) b)A B

P T

1 2 3

FB

A

Y

A B

1 2 3

A

B

F

P T

Y



5.1.1 DIRECTLY CONTROLLED PRESSURE RELIEF VALVES

Basic principle:The inlet pressure p acts on a measuring surface A and the force F resulting from it iscompared with that of a spring. When the pressure exceeds the value set on the spring, thevalve body (cone or piston) moves against the spring and opens a connection between inletand outlet. The pressure level to be limited is closed loop controlled regardless of the flow rateQ whereby the valve body occupies any intermediate position (Control valve).

Graphical symbol:Pressure valves generally are represented in the circuit diagram by a square with an arrow.The position of the arrow which shows the flow direction indicates whether the two mainconnections are connected with each other or are shut off against each other, i.e. whether thevalve is open or closed.How the valve is influenced by springs and pressures, is represented outside the square. Inthe case of the pressure relief valve the inlet pressure acts against the spring. The valve isrepresented in its inoperative position, so closed.

Seat and slide valvePressure relief valves can be executed as seat or as slide valve. Seat valves have theadvantage of small regulating distances and thus of short reaction times as well as of theabsolute tightness. In order to prevent a whirling of the valve cone, this is often combined witha damping piston.

p

G

p

G

A

F

open closed Pressure release valve




Pressure valves in slide method of construction possess the possibility of the fine control:when the control edges are provided with notches, when opening the valve at first a smallopening cross-section is released and thus control accuracy and stability of the valve areincreased. The cover ü is a compromise between tightness and speed of response.

5.1.2 PILOT OPERATED PRESSURE RELIEF VALVES

Bigger volume throughputs require corresponding flow rate cross-sections and so strongersprings which must finally hardly be adjusted any longer and require a big installation space.Therefore handy pressure valves for bigger flow rates are constructed pilot operated. Further,this principle guarantees more favourable characteristic lines.The device consists of a main and of a pilot control stage whereby the latter one is a simplepressure relief valve in seat method of construction. It is the error sensing device of thesystem, on whose spring the minimum pressure of response of the total valve is set. The mainstage can be executed as slide or as seat valve. The inlet pressure gets on the lower front side of the main valve and via a throttle also on itsupper side (the throttle can be arranged in the moving slide as well as in the fixed housing).From there exists a connection to the pilot valve. As long as this does not react, the main valveis pressure-compensated and is kept in closed switch position by a relatively weak spring.When reaching the opening pressure on the pilot valve, from the input a small control oilcurrent flows through the throttle and the pilot valve. This produces on the throttle a pressuredrop and thus a difference force between under and upper side of the main valve, which itfinally pushes against its spring upwards, through which the connection from the input to theoutput is opened.The pilot oil flow arising on the pilot valve can be carried off corresponding to the case of useinternally into the outlet or externally via an additional waste oil connection. It must beobserved that a possible return pressure in the outlet in case of internal waste oil carrying-offis added to the setting value on the pilot valve.

Seat valve

Damping piston

Slide valve

Precision control



Graphical symbolMain and pilot valve can be represented in resolved form also in the circuit diagram. Often asimplified graphical symbol is used, however. The kind of the pilot carrying-off is alsoexpressed here.

Graphical symbolFrequently pressure relief valves must be relieved via an electric signal, i.e. be madepressureless. The small directional valve required for this purpose is set on the pilot valvedirectly. This combination offers itself as low-priced solution for a pressureless circulation.

Main stage slide valveMain stage seat valve

Throttle

Main valve

Control oil eductionalternatively internally externally

Pilot valve

simplified graphical symbolcomprehensive graphical sym-

Control oil carry-

inter-

external

Pilot valveMain valve




5.2 PRESSURE RELIEF VALVE

While the pressure relief valve limits the whole operating pressure in a plant to a certain level,it is the task of the pressure release valve to reduce the pressure in a certain branch for aspecial consumer. A connection opened at first closes continuously when the inlet pressure rises above the setvalue. The open normal position as well as the actuation from the outlet is expressed in thegraphical symbol.

Symbol comprehen- Symbol simplified

Pressure in total plant Pressure in special branch

Pressure relief valve

Pressure release valve

p2p1

p1

p2



5.2.1 DIRECTLY CONTROLLED PRESSURE RELEASE VALVE

Corresponding to the task here not the inlet pressure, but the outlet pressure is given on ameasuring surface A and the force F resulting from it is compared with a spring. If this pressureexceeds the value set on the spring, the valve slide moves and closes a connection openedbefore between the two connections. The pressure level to be decreased is closed loop controlled regardless of the flow ratewhereby the valve slide occupies any intermediate position (control valve). Pressure reliefvalves are almost exclusively constructed as sliding valves because here less the tightness asrather the possiblility for fine control, even with smallest flows, is important.

5.2.2 PILOT OPERATED PRESSURE RELIEF VALVE

For the already explained reasons also pressure relief valves are constructed pilot operatedfor bigger flow rates. Such devices consist of a main and of a pilot control stage. The latter oneis again a simple pressure relief valve in seat method of construction. The main stage is mainlyconstructed as sliding valve (fine control) and is open in the inoperative position. The outlet pressure to be controlled gets on the lower and via a throttle on the upper front sideof the main valve. From there exists again a connection to the pilot valve. When reaching theminimum pressure of response the pilot valve opens and a control oil current flows through thethrottle in the main valve. Due to the pressure drop also the main valve moves against itsspring upwards and closes the connection from the inlet to the outlet in order to keep so theoutlet pressure constant. Pilot operated pressure relief valves also maintain the control process then when no oil isneeded by the consumer. During the control process a certain control oil current must beapplied permanently via the inlet, however. This control oil current must basically be carried offexternally.In the same way as the pilot operated pressure relief valves pressure release valves can beremote pilot operated or be actuated via several pilot valves which can be called up.




5.3 PROPORTIONAL PRESSURE VALVE

Stepless change of the pressure proportionally to an electric input signal is enabled bypressure proportional valves. Instead of the spring at a mechanically adjustable pressure reliefvalve a proportional magnet is used.The setting of the pressure occurs depending on the current via the proportional magnet.Higher input current means bigger magnet force and thus higher pressure setting.In order to increase the repeatability, the position of the armature of magnet is controlled by acontrol system.

The armature of the position-controlled proportional magnet acts on a pressure spring, whichin turn presses a valve cone against its seat. Depending on valve travel a spring pretensionand thus a certain opening pressure results.

Act.val

Set valueElectronics

Armature of

ferrite-coreStroke transducer

Valve spring Valve seat

Valve cone

Symbol



6 VOLUME/FLOW CONTROL VALVES

The task of the flow control valves is to influence the volume throughput Q by changing athrottle cross-section in order to control so speeds of cylinders and hydraulic motors.The excess flow conveyed by fixed displacement pumps is carried off to the tank by thepressure relief valve. Variable displacement pumps closed loop control correspondingly back.Depending on the achievable accuracy one distinguishes between throttle valves and flowcontrol valves. The graphical symbol hints at a contraction of the wire cross section.Frequently throttles and flow control valves are only needed for one flow direction. For thispurpose they are combined with a check valve and throttle check valves arise.

2-Directional-flow control

3-Directional-flow control

Throttle check valve Current

Throttle variable

Throttle fixed




6.1 THROTTLE VALVES

6.1.1 FLOW LAW

On a restricted flow zone there is a square connection between flow rate Q and pressuregradient Dp according to the connection.

Q2 ~DpSo when the inlet or outlet pressure on a throttle changes, a change of the pressure differenceDp and so also a variable flow rate Q arises.In practice the inlet pressure p1 is often kept constant by a pressure relief valve or by thepressure controller of a variable displacement pump. Variations of the pressure difference Dpresult due to different stresses on the consumer and thus different outlet pressures p2.So simple throttle valves can only be employed then when the load pressures p2 change littleor when a consumer speed dependent on the load is accepted and/or wanted.

6.1.2 THROTTLE FORMS

The influence of the viscosity (high viscosity of the pressure medium) on a restricted flow zoneis essentially determined by its form. It is the stronger the bigger the wetted area in proportionto the throttle cross-section is. Hence an ideal, i.e. as viscosity-independent as possiblerestricted flow zone is the circular diaphragm with as short as possible throttle distance. At this form the ratio from area and circumference is a maximum. Changing throttle cross-sections can hardly be made as infinitely variable circular areas. An acceptable compromiserepresents the equilateral triangle.

F load = variable

p2

(variable)

p1

(constant)

Q∆p

v

Setting

Q²~ ∆p

Q

∆p



6.1.3 CONSTRUCTIVE DESIGN OF THROTTLES AND THROTTLE CHECK VALVES

At the represented devices the variable throttle cross-section consists of two or four triangularnotches worked into a sleeve whose areas can be changed by axial displacmeent of thesleeve via a spindle. At the throttle the sleeve is pressed downwards regardless of the flow direction, at the throttlecheck valve the sleeve lifts off in the case of the flow direction B-A and releases the full flowrate cross-section.

Dia- Throttle

Needle throttle Piston throttle

ThrottleThrottle check valve

Throttle cross-sec-




6.2 FLOW CONTROL VALVES

6.2.1 TWO-WAY FLOW CONTROL VALVE

When a constant speed on a consumer is requested irrespective of the load, a flow controlvalve must be employed. Its characteristic line shows a horizontal profile, i.e. the flow rate isindependent of the pressure difference applied on it. Only with very small pressure differences(approx. 8 bar) the flow rate decreases.

6.2.2 FLOW CONTROL VALVES

Mode of actionWork direction B - F:Flow rate in its size largely constant as a result of the equilibrium setting itself between internalpressure gradient and initial stressing force of the control plunger spring.Opposite direction F - B:Flow rate as a function of the pressure gradient in its size not constant.

P

P

Q

v

Q Setting

F load = variable

p2

(variable)

p1

(constant)

Control edge Control edge



6.2.3 THREE-WAY FLOW CONTROL VALVE

At this version the pressure balance lies in parallel to the measuring throttle. The throttle cross-section of the pressure balance is closed in inoperative position. Variations of load on theconsumer are corrected by the fact that this throttle cross-section is opened more or less andthe excess flow conveyed by the pump is carried off to the tank via the third connection.

6.3 PROPORTIONAL THROTTLE AND/OR FLOW CONTROL VALVE

Stepless change of the flow rate proportionally to an electric input signal (U = 0-10 V) enableproportional throttle valves. These essentially consist of a sliding valve with fine controlnotches whose opening cross-sections are changed by a proportional magnet.For increasing the repeatability the position of the valve slide is controlled by a control system.The actuation of the valve occurs by a special electronics.When the proportional throttle valve is combined with a pressure balance, a load-compensated flow control valve arises.

Q3 Residual

Q2

Main cur-

Q1

Inlet current

Pressure bal-

Measuring

Q2

Q3

Q1

P2

∆P

P1

Act.val

Set value

Stroke trans- ferrite-core

Magnet coil

Armature of

Valve slideReturn springElectronics




6.4 PROPORTIONAL DIRECTIONAL VALVE

Symbol for the proportional valve

Sectional drawing with directional valve as shut-off valve

BOSCH PROPORTIONAL DIRECTIONAL VALVE with integrated control card

For larger volume throughputs the principle of the pilot control known from the control valvesis applied. As main stage serves a modified directional valve NG 10, 16 or 25 withcorresponding leading edges. The pilot valve is a control valve NG 6 with zero cover in themid-position. Pilot control and main stage are equipped with a stroke transducer for theposition control of the valve slides. The electronics of the two control circuits superimposed to each other as well as the end stagefor actuating the magnet are integrated in the pilot valve.The advantage of this integrated electronics lies in a low installation expenditure; anadaptation of electronics and valve does not occur at the putting into operation, but already atthe works.

A C1 B

X T C2 P Y

Pilot valve

Directional

Main valve

C1 and C2 load tapping for pressure balanceX = External control oil connectionY = External leakage oil connectionDirectional valve as shut-off valve for enabling the main stage in one direction

C1 T A P B X C2 Y



The modification to internal control oil supply P and carrying-off T occurs by removing theplugs, which are accessible after taking off the pilot valve.

Supply voltage:Terminal A: 24 V = input signalTerminal D: 0.... 10 VTerminal B:0 VTerminal E: 0 VTest signal: Terminal F:0..... 10 V proportional to the stroke of the main slide Terminal C:0 V

7 MOOG SERVOVALVES

The term ”Servo” quite generally says that a small input variable causes a big output variable.In electrohydraulic pressure and speed control loops servovalves are employed on the basisof their fast reaction.For an exact and as independent of disturbing influences as possible conversion of the electricinput signal in flow or pressure the control plunger is position closed loop controlled.

Method of operation of mechanically position-controlled valves: An electric current (input signal) in the coils of the torque motor produces depending onpolarity a torque on the anchor acting clockwise or counterclockwise. This torque deflects thebaffle plate between the two nozzles. Thus the outlet cross-section of the one nozzle isincreased and that of the other one is decreased.The pressure difference arising in this way acts on the faces of the piston valve and causes itsdisplacement. A restoring spring fixed on the armature is tensioned by the displacement of thepiston valve. The movement of the piston is finished when the restoring spring torque is in equilibrium withthe electromagnetic torque. In this state the armature-baffle plate unit is approximately againin the mid-position and the piston valve deflection is proportional to the input signal. The piston valve stops in this position so long until the electric input signal is changed.The real throughput from the valve to the consumer is dependent on the valve pressure drop.

C1 T A P B X C2 Y




Method of operation of electronically position-controlled valves

Like at the mechanically position-controlled valves this causes a pressure difference on thefaces of the piston valve and causes its displacement.

Torque motor

Control coil

Arma- Baffle plate

Nozzle

Restoring spring

Control pistonLoad differential

Control current

PS

A

C2 C1∆PL

PS R

PS

R Ps B

Fixed throttle

PsPS

PS PS

R

RR

Main-con-trol

Before-con-

site-con-

Position transduc-

XQvI∆UUQS

ULI

PS

Posit. control-

Position transducer

PS UQS

ULI

C2 ∆PL C1

PSRRPS



The position transducer supplied via an oscillator measures the position of the control plunger(actual value ULI). This actual value rectified by a demodulator is led back to the positioncontroller, which compares it with the set value UQS. The position controller actuates thetorque motor so long until set and actual value are equal. As a result the position of the control plunger is proportional to the electric set value.Simplifying the position set value is designated as throughput set value. The real throughputfrom the valve to the consumer is dependent of the valve pressure drop.

Two-stage Moog valves with electronic position control

T A PBP

Pilot control

Main stage

Position transducer

External pilot oil connection Xwith built-in disk filter

X

Y

Pilot control

External control oil connection with built-in pipe filter

Position trans-

External control oil outlet to the

A

Y = External control oil X = External control oil nectionT= TankA, B= consumer

BT P




7.1 MAINTENANCE INSTRUCTIONS D061-6 MOOG

Filter change of the construction series DO61-6.. Preferably these valves are used as pilotvalves at MOOG proportional valves of the construction series D64x, D65x and D66x.

Preparatory work

The valve need not, when well accessible from all sides, be removed from the plant for thefilter change and/or be dismounted from the main stage. Especially to both end caps (7) theaccess must be possible well. During the filter change - valve is partially open - pay attentionto clean and dustfree environment.

Disassembly instructions

1. Clean valve externally carefully, especially in the area of the end caps (7)

X

Y 2. Stage with pipe filter

3. Level

1. Stage (Torque motor with mechanical feedback)

Adjustable

Set valueU=+10V Stroke transducer

Act.valComparator A BT P

X

Y 17/25

13

7

14 9 12 1 10 28

Bild 2

Bild 1



2. Remove in each case both screws with hexagonal recessed hole (17) with hexagonalrecess key SW 4 and/or 5/32. Observe spring rings (25).

3. Take off both end caps (7).

4. With extractor (Figure 2) extract both plugs (28) with O-rings (13). Pay attention to thatthe extractor is only under tension in order that the threaded pipe of the extractor doesnot break off.

5. At first extract from one side fixed throttle (9) with O-ring (14) by means of the sameextractor (Figure 2) in consideration of the procedure described before. The filter pipe(10) will still remain in the bore.

6. Then from the other side also extract fixed throttle (9) with O-ring (14) together with thedetached filter pipe

7. Control filter installation bore for cleanness. Please pay attention to that, when the filterpipe is soiled especially strongly externally, possibly dirt stripped at the removal remainsadhered in the filter channel. Then remove this dirt from the bore before the installationof the new filter with a fluff-free cloth with the aid of a wire. The filter element cannot becleaned sufficiently by washing out or blowing out, and must therefore always berenewed in case of visible soiling or because of wire cloth already deformed due to highdifferential pressure.

Assembly instructions

1. Blow out fixed throttles (9) from both sides and in addition still rinse through if purecleaning fluid not agressive towards O-rings or oil are available.

2. Check O-rings (13) and (14) on fixed throttles and plugs for intactness.

3. Grease O-rings with clean grease or oil.

4. Put new filter element (10) on one of the fixed throttles (9). Screw extractor (Figure 2) infixed throttle.

5. Press in combination from one side fixed throttle (9) also by means of extractor.

6. Press in fixed throttle (9) from other side also by means of extractor. Filter pipe iscentred here by the conical fixed throttle tip.

7. Press in the plugs (28) with compound O-rings (13) from both sides. Plugs will stillproject somewhat on the housing.

8. Tighten end caps (7) with the two each screws with hexagonal recessed hole (17) andspring rings (25). Tightening torque here 7 Nm.

9. After test run pay attention to external tightness.




7.2 MAINTENANCE INSTRUCTIONS D641/661, D651/656, D659 MOOG

Filter change of the construction series D641/661, D651/656, D659

Disassembly instructions

1. Clean valve externally carefully, especially in the area of the filter cover (20).

2. With hexagonal recess key SW3 remove the four screws with hexagonal recessed hole(38).

3. Take off filter cover (20). Filter plate (21) is visible now.

4. Remove filter disc (21). For this purpose take out the filter disc with electronics engineerscrewdriver or scribing iron without damaging the installation room.

Attention!

For the dirt control the filter plate (21) must be taken out. The dirt is notvisible with removed filter cover (20) as it is on the inside.When the filter disk is removed, it can be damaged. Moreover, there isthe danger that it is built in again contrary to the preceding installationdirection (previous dirt side now outside). In such a case the valve isendangered in its function by the fact that dirt gets through the oil cur-rent into the Pilot control system is rinsed.When the filter plate has been taken off, this should be replaced by anew filter plate A67999-100 in each case for reasons of safety.

Assembly instructions

1. Check internal O-ring (53) for correct seat and intactness

2. Use new, unsoiled filter disk (21).

3. Check O-ring (59) on filter cover (20) for intactness, grease with clean grease or pure oiland then press filter cover (20) with O-ring (59) cautiously into the installation room.

4. Tighten filter cover (20) with screws with hexagonal recessed hole (38). Tighten all fourscrews with 3 Nm torque.

5. After putting into operation check the valve for external tightness.

20

38

21

59

53



7.3 RANGE D061-7 AND D630-*

At these construction series the filter cover and the plug are executed separately, see Figure3. Therefore, when the cover is dismounted, the plug must be extraced separately by meansof extractor, see Figure 2.

Attention!

At range D061-7 for the dirt check the filter disc must be taken out. Thedirt is not visible with removed stopper as it is on the inside. Here the fil-ter disc is flown through from inside to outside. The filter disc of therange D630-* is flown through inversely.

7.4 ERROR POSSIBILITY AND CHECK

Soiling:reduced dynamics, increased waste oil (leading edges wear), control accuracy is reduced(amplification in the 1st stage changes) Check protection filter.

Hint!Mark disk filter; in case of doubt exchange filter (fine dirt can often not be recognized)

Control circuit oscillates, possible reasons:Circuit amplification too high, batches in the stroke transducer

Undervoltage: Voltage < 12 VValve goes in the piston position without electric supplyCheck power supply.

Other things:pressure is applied on the pilot control stage?Zero point adjustment Measurement piston position signal (pin F)Test valve in the open control circuit (valve tester)

Bild 3

Cover

Plug




BARREL (6)

The hydraulic cylinder is the well most known hydraulic component. It makes the effect ofhydraulic forces visible and produces the different work movements on the machine. Thecylinder produces rectilinear movements with a minimum of constructive expenditure with thebiggest power density. Forces and speeds remain constant over the whole stroke.

Mode of action:

Hydraulic oil acts via the connections around bottom cylinder casting and/or cylinder head onthe piston area. The movement resulting from it is passed on to the machine via the piston rod.In order to guarantee a perfect sealing on piston and piston rod, the functions guide and sealare separated in design.

Components:

[1] Cylinder head

[2] piston rod

[3] Cylinder pipe

[4] Piston

[5] Cylinder bottom

[6] Dirt scraper

[7] Bar packing

[8] Rod guidance

[9] Piston guide

[10] Piston packing

1 2 3 54

6 7 8 109


Barrel (6)89


Graphical symbol:

Formulas:

Basic formula:F = p * A

Altered formula at which the following units can be used. The conversion of units has alsobeen integrated into the following formula and is no longer observed.F = p * A * 10

F ..... Force in Np .....Pressure in barA ..... Area in cm2

Basics:

When one neglects the friction, the following is valid with force equilibrium:

F1 = F2 + F3

When the force F1 or F2 + F3 is bigger, the piston moves in the direction with the bigger force.

double-acting single-acting with retaining spring

with piston rod on both sides

Plunger cylinder)

with adjustable damp-ing on both sides

F3 = F2 = 10 * p2 * A2 F1 = 10 * p1 * A1

Barrel (6) Creation date: 18.03.200390 Printing date: 20.3.2003


When the piston rod side is blocked, and we set the force F3 = 0, the appearing pressure onthe piston rode side depends on the supply pressure and on the area ratios.

Example:

p1 = 200 BarA1 = 200 cm2

A2 = 100 cm2

p2 = (10 * p1 * A1 - F3) / (A2 * 10)p2 = (10 * 200 * 200 - 0) / (100 * 10)p2 = 400 Bar !!

When the piston rod side is separated with a slide, and pressure is built up on the piston sidenevertheless, on this side higher pressures appear. It is absolutely required that the maximum pressure in this pipe is not exceeded. If necessary,on the piston rod side a pressure relief valve must be built in. So a destruction of componentsis prevented.

F3 =0 F2 = 10 * p2 * A2 F1 = 10 * p1 * A1


Barrel (6)91


The cylinder can, when a pressure relief valve is built in, still be moved so long until it reachesa stop, however. This often takes place with movements by jerks and jolts as, when thepressure relief valve opens, a pressure drop takes place and the oil is compressed anew onthe piston rod side.

The existing residual pressure moves the load back again for a while when the piston side isrelieved.

Pressure intensifier:

This principle of the increase of the pressure is applied deliberately. Two pistons of differentsize are connected fixed with a piston rod. When one pressurizes1 the area A1with thepressure p, one gets on the large piston the force F1. This force is transmitted to the smallpiston by the piston rod. The force acts on the area A2 and causes the pressure p2.

Without frictional losses is valid:

F1 = F2 = F

270bar

280bar



Pressure intensifier connected fixed

p2 = p1 * A1 / A2

Pressure intensifier integrated into cylinder

Application: increased opening force at DUO machines

Neglecting the frictional forces and with the prerequisite that p2 and p4 is connected with tank,and p3 is closed, the following formulas are valid:

F4 = F3

F2 = F1

F3 = 10 * A3 * p3

F2 = 10 * A2 * p3

F1 = 10 * A1 * p1

F2 = 10 * A1 * p1

F4 = 10 * A3 * p3

F4 = 10 * A3 * A1 * p1 / A2

h

h

A1 A2

F1p1 F2 p2

A1 A2 A3

F1 F2 F3 F4

p1 p2 p3 p4


Barrel (6)93


Speed:The speed of the cylinder can be calculated by means of the following formula:Basic formula:qv = A * v

Altered formula at which the following units can be employed. The conversion of units has alsobeen integrated into the following formula and is no longer observed.

qv = A * v * 0,1

qv .....Volume throughput in l/minA ..... Area in cm2

v .....Speed in m/min

Calculate the moving speed of the cylinders

The following values are available:

A Piston area = 200cm2

A Piston rod side= 100cm2

qv = 100 l/min ( Pump)p max (pump) = 200 bar

270bar 270bar

Move out cylinder:

v = qv * 10 / Av = 100 * 10 / 200v = 5v= 5 m/min

Move in cylinder:

v = qv * 10 / Av = 100 * 10 / 100v = 10v= 10 m/min



When we now compare both results, we detect that we move the piston with different speeds.This comes from the fact that we have different areas available.

There are the following possibilities to get the same speeds at the cylinder moving-in andcylinder moving-out:

The same area for both movements

different volumes for both directions

Differential system

Differential system:

Here the displaced oil of the piston rod side is led to the piston side in addition. The cylinderruns through the different force conditions between piston side and piston rod side.

Cases of application at Engel: Injection: -> with / without increased spec.injection pressure (switchable for operator)Mold opening / mold closing - moving cylinderPressure pad process - DUO machines

270bar


Barrel (6)95


At these movements not only the differential connection is switched, also different quantitiesare output!



HYDRAULIC SYMBOLS (7)

1 ENERGY CONVERSION

1.1 HYDRAULIC PUMPS

1.2 HYDRAULIC MOTORS

Pump with constant displacement vol-ume

Variable displace-ment pump with electrohydraulic adjustment

Pump with adjust-able displacement volume

Variable displace-ment pump with electrohydraulic adjustment

Variable displace-ment pump with control cylinder

Motor with constant displacement vol-ume

Motor with adjust-able displacement volume

Motor with constant displacement vol-ume

Variable displace-ment pump + vari-able displacement motor


Hydraulic symbols (7)97


1.3 BARREL

double-acting single-acting with retaining spring

with piston rod on both sides

Plunger cylinder)

with adjustable damp-ing on both sides

Hydraulic symbols (7) Creation date: 18.03.200398 Printing date: 20.3.2003


2 ENERGY OPEN LOOP CONTROL AND ENERGY CLOSED LOOP CONTROL

2.1 DIRECTIONAL VALVES

3/2 directional valves (3 connections, 2 switch positions)

2/2 Directional valve

4/2 Directional valves (4 connections, 2 switch positions) actu-ated electromagneti-cally with spring resetting)

4/3 directional valves (4 connections, 3 switch positions) electromagnetically actuated with spring centering

4/3 Directional valves electrically actuated, spring centered, blocked in the mid-position with waste oil carrying-off for avoid-ing cylinder drift

4/3 Directional valves electrically actuated, spring centered with nozzles in both work-ing lines for the relief in the inoperative position

Analogously working 3/2 directional valve, hydraulically actu-ated with adjustable spring resetting (Con-trol valve)

4/2 Directional valve mechanically actu-ated, electrically monitored, with spring resetting

4/2 Directional valve with hydraulic pilot control and spring resetting

4/2 Directional valve electrically actuated, electrically moni-tored, with spring resetting

Pressure-dependent switchover stage

4/3 Directional valve with electric actua-tion, hydraulic pilot control and spring centering

SU




2.2 SHUT-OFF VALVES

2.3 INTERNAL VALVES ( CARTRIDGE )

Non-return valve spring loaded

Shuttle valve, two-way valve

Electrically pilot con-trolled check valve with spring resetting

Check valve hydrauli-cally pilot controlled

pilot controlled dou-ble check valve

Seat valve with aspect ratio 1:1,6

Seat valve with aspect ratio 1:1

Seat valve with area ratio 1:1.6 and fine control notches

Seat valve with area ratio 1:1 and fine con-trol notches

Seat valve with area ratio 1:1.6 and with relief of the spring space towards B= Non-return valve

Seat valve with area ratio 1:1 and with relief of the spring room towards B= Non-return valve

Seat valve with area ratio 1:1.6 and fine control notches as well as switch position monitoring

B

F

A

F

B

A

F

B

A

F

B

A

F

B

A

B

F

A A

F

B

A

F

B

F

B

A

F

B

A

F

B

A

F

B

A

F

B

A

F

B

A

F

B

A

F

B

A

B

F

A

F

B

A A

F

B



2.4 PRESSURE VALVES

Sliding valve with area ratio 1:1 and built-in diaphragm in inoperative position open (e.g. for pres-sure relief function)

Sliding valve with area ratio 1:1 in inop-erative position open (e.g. for pressure bal-ance function)

Sliding valve with area ratio 1:1 in inop-erative position closed with spring arranged below

Seat valve with area ratio 1:1.6 with shaft seal between B - F.

Seat valve with area ratio 1:1 with shaft seal between B - F.

Seat valve with area ratio 1:1.6 with shaft seal between B - F and fine control notches

Seat valve with area ratio 1:1 with shaft seal between B - F and fine control notches

Pressure relief valve adjustable manually

Pressure relief valve pilot operated hydraulically

Pressure relief valve adjustable manually

3-Directional pres-sure relief valve man-ually adjustable

3-Directional pres-sure relief valve hydraulically pilot operated

Position-controlled proportional pres-sure relief valve

F

B

A

F

B

A

F

B

A

F

B

A

F

B

A

B

F

A

F

B

A

B

FF

B

A




2.5 VOLUME/FLOW CONTROL VALVES

Throttle fixed Throttle variable

Throttle with check valve

Fixed set volume/flow control unit

Position-controlled proportional throttle valve

Position-controlled proportional pilot valve

Pilot operated control valve

Hydraulically con-trolled proportional valve

Control valve

Control valve for RKP

Control valve with integrated electronics

SU

US



3 ENERGY SOURCES, ENERGY TRANSMISSION, ACCESSORIES

3.1 PIPINGS

3.2 ENERGY SOURCES

Working line flexible piping

Tank line Cable connector

Control conduit Hydraulic block

Oil leakage pipe Measuring connec-tion

Quick-action coupling

Electric motor Connection to hydraulic energy source




3.3 ATTACHMENT

Tank Manometer

Oil level switch with sight glass

High-pressure filter with by-pass valve and soiling display

Thermostat Temperature couple

Filter with electric soil-ing display

Oil cooler

Oil filler cap with vent-ing filter

Manometer selector switch

Pressure transducer Storage

-+

PU



MALFUNCTIONS ON HYDRAULIC DEVICES (8)

The following table shall help at the location and elimination of sources of disturbance. It doesnot lay any claim to completeness as such a table would go beyond the possible scope, butcontains the so far main reasons of the disturbances within hydraulic plants.

The indicated means for the elimination are based on practical experience and do not excludeoverhauls going beyond our recommendations.

For repairs a technically qualified personnel should be available. At the dismounted devicesparts as well as in case of renewed assembly it must be paid attention to absolute cleanness.

Each soiling decreases the life of a hydraulic plant.

GENERAL SURVEY

1. Pump and motor

2. Directional control slide valve

3. Pressure valve

4. Throttle and volume/flow control unit

5. Barrel

6. filter

7. Tank

8. Oil cooler

9. Sundries

1 PUMP AND MOTOR

1.1 PUMP DOES NOT CONVEY

Source of disturbance Elimination

a) Wrong direction of rotation a) Change poles of motorb) Oil level too low b) Refill oilc) Filter clogged c) Clean filterd) Air in the system d) Ventilate systeme) Suction pipe leaky e) Sealing and/or replace sealf) Pump shaft broken f) Find out reason (pump distorted) and

replace shaftg) Wrong oil quality g) Observe oil recommendationsh) Oil too cold h) Warm up pump with low pressurei) Pump controller defective i) Check control valve


Malfunctions on hydraulic devices (8)105


1.2 PUMP OR MOTOR PRODUCE HEAVY NOISE

1.3 PUMP OR MOTOR OVERHEATED


a) Cavitation a) Ventilate and/or seal systemb) Suction line leaky b) Sealing and/or replace sealsc) Shaft seal leaky c) Replace shaft seald) Oil foams d) Ventilate system e) Ventilation clogged e) Clean ventilation filterf) Suction filter clogged f) Clean filterg) Housing leaky g) At first tighten screws, otherwise check for

cracks and sealingh) Wing spring broken h) Replace springi) Pumps or motor insert defective i) Replace damaged partsk) Pump or motor distorted K) Check plane surface of the assembly area and/

or tighten screws uniformlyl) Foreign matter in the induction l) Remove foreign matter, possibly flush systemm) System soiled m) Flush system or possibly heat and flush systemn) Pipe bends in the induction n) Eliminate or at least decrease bendso) Oil temperature too high o) Check circuit diagram for reason (Cooling?)p) Vibrations p) Find out reasonr) Oil level too low r) Refill oil (leakage?) System not filled? Losses?s) Wrong oil quality s) Observe oil recommendations


a) Wrong oil quality a) Oil recommendationsb) Oil level too low b) Refill oil (leakage?) System not filled?

Losses?c) Rotation group pump or motor worn out

c) Pump and/or motor employment possibly exchange control plate

d) too high radial or axial load d) Restrict to allowed measuree) Insufficient cooling e) Increase cooling capacityf) Cooling system clogged f) Find out reason and eliminate defect (Calcare-

ous deposit)g) Pressure too high g) Reduce pressure settingh) Malfunction in the system h) Check idling solenoid (pressureless circula-

tion)i) Filter clogged i) Clean filterk) Cavitation k) Ventilate and/or seal systeml) Oil foams l) Ventilate systemm) Ventilation clogged m) Clean ventilation valven) System soiled n) Flush or possibly heat and flush system

Malfunctions on hydraulic devices (8) Creation date: 18.03.2003106 Printing date: 20.3.2003


1.4 PUMP DOES NOT DEVELOP ANY PRESSURE

1.5 SPEED LOSS ON THE MOTOR

1.6 MOTOR DOES NOT TURN

1.7 SHAFT PLAY TOO BIG


a) Wrong pressure setting a) Change pressure setting and/or no pressureIncrease pressure

b) Pressure valve jams b) Eliminate defectc) Electric faulty switching sliding mag-net, pressure valve

c) Check electric connection diagram (Valve or solenoid switched to circulation?) Eliminate defect

d) Leakage in the system (Cylinder, valves)

d) Seal system - replace damaged parts

e) Pump shaft broken e) Pump does not conveyg) Wrong oil quality f) Check pump controllerh) Drive machine defective g) Observe oil recommendationsi) System soiled h) Repair drive machine (Find out reason)i) System soiled i) Flush or possibly heat and flush system


a) Control plate is not applied a) Dismount motor and eliminate reasonb) Motor insert defective b) Replace damaged partsc) Oil temperature too high c) Check connection diagram for reason


a) Waste oil on the motor a) Check ball valve. Check whether control plate is applied

b) O-ring on control plate defective b) Replace O-ring. Check whether lifting ring defective


a) Bearing defective a) Exchange bearingb) too high radial or axial load b) Flush and possibly heat and flush systemc) Coupling is unbalanced c) Counterbalance or replace coupling




1.8 LEAKAGE ON PUMP OR MOTOR

2 DIRECTIONAL VALVES (SOLENOIDS)

2.1 SLIDE JAMS

2.2 SLIDING MAGNET DOES NOT SWITCH

2.3 PRESSURE VALVE DOES NOT SWITCH


a) Connections leaky a) Check sealb) Shaft seal leaky b) Replace shaft sealc) Housing leaky c) Check for cracks and possibly replaced) Damage of the plane surfaces d) Machine plane surface cleanly


a) Slide distorted a) Loosen slide and tighten it uniformly (Check plane surface)

b) Dirt in the system b) Flush or possibly heat and flush systemc) Condensation water in the sys-tem

c) Check chiller and/or check system for condenser effect

d) Wrong oil quality d) Observe oil recommendationse) Oil resinified (long storage) e) Clean slide and possibly new oil fillingf) Housing part mounted wrongly f) Observe assembly sequenceg) Wrong seals g) Replace by prescribed sealsh) Oil temperature too high h) See 7.3 and 8.1i) Oil too cold (Fluid friction) i) Heat up system by pumpk) Slide defective k) Repair slide


a) Magnet burnt-out a) Check reason - replace magnetb) Slide jams b) See 2.1c) No voltage c) Check network and/or check safeguardingd) Electric faulty connection d) Check electric circuit diagram


a) Slide jams a) See 2.1b) No pressure b) Check system (1.4, 3.2, 3.3)c) Control conduit is missing c) Install control conduitd) Control conduit clogged d) Clean piping (local constriction)



2.4 SLIDE OVERHEATED

2.5 SLIDE PRODUCES HEAVY NOISE

2.6 LEAKAGE ON THE SLIDE

3 PRESSURE VALVE

3.1 VALVE FLUTTERS


a) System temperature too high a) Reduce pressure setting or install coolingb) Wrong oil quality b) Observe oil recommendationsc) Dirt in the system c) Flush or possibly heat and flush systemd) Electric faulty connectionswitcho-ver

d) Check electric circuit diagram

e) Slide jams e) See 2.1f) Slide defective f) Repair slide


a) Oscillations in the system a) Snap rivets for casingb) Slide defective b) Repair slidec) Slide jams (Magnet buzzes) c) System for soiling (see also 2.1a)


a) Connections leaky a) Check seals (Special fluid-special seals)b) Seal defective b) Replace sealc) Screw couplings loose c) Tighten screw couplingsd) Slide defective d) Repair slide (Cracks in the housing?)


a) Valve defective a) Exchange partsb) Pilot control defective b) Repair pilot controlc) Wrong oil quality c) Observe oil recommendationsd) Dirt in the system d) Flush or possibly heat and flush systeme) Dampening defective e) Repair valve and/or change spring




3.2 VALVE JAMS

3.3 VALVE DOES NOT SWITCH

3.4 VALVE OVERHEATED

4 THROTTLE VOLUME/FLOW CONTROL UNIT

4.1 DEVICE DOES NOT CLOSED LOOP CONTROL


a) Valve distorted a) Loosen screws and tighten them uniformlyb) Oil temperature too low b) Heat up system by pumpc) Oil leakage pipe is missing or under pressure

c) Install pipe or separate it from return

d) Further sources of error under 2.1b-h

d) See 2.1b-h


a) Valve spring broken a) Replace springb) Valve jams b) Find out reason and eliminate defect


a) System temperature too high a) Observe maximum pressureb) Oil speed too high b) Install valve of larger nominal width


a) Device distorted a) Loosen screws and tighten them uniformlyb) Seat defective b) Change seatc) Throttle cone defective c) Exchange coned) Check valve jams d) Check and possibly exchange cone and

seat (Spring fracture)e) Fine throttle jams e) Exchange throttlef) Compensation mechanism defective f) Dismount controller and exchange defec-

tive partsg) Piston jams g) Check system for soiling, exchange piston h) Spring broken h) Exchange springi) Corrosion on the adjusting mechanism i) Clean or possibly exchange



5 BARREL

5.1 CYLINDER WANDERS

5.2 CYLINDER JAMS

5.3 NONUNIFORM RUNNING

6 FILTER

6.1 BAD FILTERING


a) Seal or sleeve defective a) Exchange seal or sleeveb) Excessive waste oil b) Check slide, replace defective parts


a) See sources of error under 2.1b-h a) See 2.1b-h


a) Differentload a) Employ following valve and mechanically oper-ated check valves

b) Pressure variation b) Check system


a) Filter clogged a) Clean filter and possibly systemb) Wrong installation b) Flush and/or heat and flush systemc) Magnetic field destroyed c) Employ new permanent magnetsd) Packing saturated d) Employ new packing (Packings cannot be

cleaned)e) Casing leaky e) Seal casing (Use Teflon band or Loctite)




7 TANK

7.1 OIL SOILED

7.2 OIL FOAMED

7.3 TEMPERATURE TOO HIGH


a) Sealing defective a) Replace sealing, possibly change itb) System soiled b) Flush and/or heat and flush systemc) Air filter defective c) Replace air filter or aeratord) Wrong air filter d) Employ suitable filtere) Casing and system unattacked e) Clean, heat and flush system thoroughly


a) Oil level too low a) Refill oilb) System not filled b) Refill system after short inflow (Losses? Leak-

age?)c) Suction and return not separate c) Displace suction and return diagonally in tank

cornersd) Return pipe over oil level d) Extend return pipee) Cavitation e) Check system for leak (Screw couplings, radial

packing ring, see also c,d)f) Wrong oil quality f) Observe oil recommendationsg) Bad ventilation a) Change ventilation


a) Cooling is missing a) Employ chiller or possibly radiating surface, change tank

b) Cooling insufficient b) Increase cooling capacity or enlarge radiat-ing surface, tank

c) Ambient temperature too high c) Change tank position or build in chillerd) Distance heat source too small d) Check tank distance or decrease radiating

surface to the heat source e) System pressure too high e) Change pressure settingf) System components defective f) Replace defective componentsg) Oil-level glass is missing, check impossible

g) Employ oil-level glass



8 OIL COOLER

8.1 BAD COOLING

8.2 WATER IN THE OIL

9 SUNDRIES

9.1 SOILING

9.2 OIL FOAMS

9.3 TEMPERATURE FLUCTUATES


a) Inlet temperature of the coolant too high

a) Use suitable coolant

b) System clogged b) Clean systemc) Cooling water supply defective c) Check water network (choose shortest con-

nection to the pump station)d) Drive line of the plant increased d) In case of increased outputs of the drive

machine check chiller type for sufficient cool-ing capacity


a) Cooling system defective a) Cooling system defectiveb) Condensation effect - cooling water inlet temperature too low

b) Check system for condenser effect (with oil flow and low water temperature condensation arises)


a) System leaky or soiled at start-up a) Clean and seal systemb) Bad filtering b) Improve filteringc) Piston rods draw in dirt c) Install stripper rings or dust sleeves


a) Air in the system a) Ventilate systemb) Cavitation b) see 7.2c


a) Cooling discontinues temporarily a) Check cooling system




AAccessories symbols . . . . . . . . . . . . . . . . . . . . . . . . . . .104Additional devices for the tank . . . . . . . . . . . . . . . . . . . . .24Advantages of oil-hydraulic control systems and drives . .15Air bubbles in the hydraulic fluid . . . . . . . . . . . . . . . . . . .20Annular gear motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50

BBad cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113Bad filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111Barrel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89Basic circuit diagram of a hydraulic circuit . . . . . . . . . . . .18Basics of the hydraulics . . . . . . . . . . . . . . . . . . . . . . . . . .13Built-in valves ( cartridge ) symbols . . . . . . . . . . . . . . . .100Built-in valves and their variants . . . . . . . . . . . . . . . . . . .64

CCare of hydraulic fluids and equipment . . . . . . . . . . . . . .21Cartridge technology) . . . . . . . . . . . . . . . . . . . . . . . . . . . .62Components bladder accumulator . . . . . . . . . . . . . . . . . .35Components diaphragm accumulator . . . . . . . . . . . . . . .36Control bores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63Conversion of energy in hydraulic plants . . . . . . . . . . . . .13Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27Cover plates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66Cylinder graphical symbol . . . . . . . . . . . . . . . . . . . . . . . .89Cylinder jams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111Cylinder symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98Cylinder wanders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111

DDanger in case of fracture . . . . . . . . . . . . . . . . . . . . . . . .15Differential system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95Directional valve functions . . . . . . . . . . . . . . . . . . . . . . . .67Directional valve with internal valves . . . . . . . . . . . . . . . .67Directional valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55Directional valves symbols . . . . . . . . . . . . . . . . . . . . . . . .99Directly controlled pressure release valve . . . . . . . . . . . .73Directly controlled pressure relief valves . . . . . . . . . . . . .69Dirt sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Disadvantages of hydraulic control systems . . . . . . . . . .14

EEnergy sources symbols . . . . . . . . . . . . . . . . . . . . . . . .103Energy transmission possibility . . . . . . . . . . . . . . . . . . . .16Error possibility and check . . . . . . . . . . . . . . . . . . . . . . . .87Excessively high external leakage losses . . . . . . . . . . . .20

FFilling and venting filter . . . . . . . . . . . . . . . . . . . . . . . . . .24filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30Flow control valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78Flow law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76

GGear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52

HHigh-pressure pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . .43Hydraulic accumulators . . . . . . . . . . . . . . . . . . . . . . . . . .34Hydraulic fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19Hydraulic fluid and accessories . . . . . . . . . . . . . . . . . . . .19Hydraulic fluid soiling . . . . . . . . . . . . . . . . . . . . . . . . . . . .19Hydraulic force and energy transmission . . . . . . . . . . . . .14Hydraulic motors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50Hydraulic motors symbols . . . . . . . . . . . . . . . . . . . . . . . .97Hydraulic oil change . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23Hydraulic pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Hydraulic pumps and hydraulic motors . . . . . . . . . . . . . . 41Hydraulic pumps symbols . . . . . . . . . . . . . . . . . . . . . . . . 97Hydraulic symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97Hydraulic valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

IImpact of the soiling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30Internal gear pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

LLeakage on pump or motor . . . . . . . . . . . . . . . . . . . . . . 108Leakage on the slide . . . . . . . . . . . . . . . . . . . . . . . . . . . 109Losses due to liquid friction . . . . . . . . . . . . . . . . . . . . . . . 14Losses due to waste oil . . . . . . . . . . . . . . . . . . . . . . . . . . 14Low-pressure filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31Low-pressure pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

MMaintenance instructions - low-pressure filter . . . . . . . . . 32Maintenance instructions D061-6 MOOG . . . . . . . . . . . . 84Maintenance instructions D641/661, D651/656, D659 MOOG 86Malfunctions on hydraulic devices . . . . . . . . . . . . . . . . . 105Manometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38Mass, pressure, force . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Monitoring of hydraulic fluids and equipment . . . . . . . . . 21Moog servovalves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81Motor does not turn . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

OOil container . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Oil foamed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112Oil foams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113Oil level control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Oil level switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Oil preheating, cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Oil soiled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112Oil temperature control . . . . . . . . . . . . . . . . . . . . . . . . . . 29Open and closed loop controlability . . . . . . . . . . . . . . . . 15Overheating of the hydraulic oil . . . . . . . . . . . . . . . . . . . . 20

PPilot controlled check valves . . . . . . . . . . . . . . . . . . . . . . 61Pilot controlled double check valves . . . . . . . . . . . . . . . . 62Pilot operated pressure relief valve . . . . . . . . . . . . . . . . . 73Pilot operated pressure relief valves . . . . . . . . . . . . . . . . 70Pipings symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Plate heat exchangers . . . . . . . . . . . . . . . . . . . . . . . . . . . 28Preheating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Pressure and throughput controller . . . . . . . . . . . . . . . . . 47Pressure filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Pressure measurement control equipment . . . . . . . . . . . 38Pressure relief valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72Pressure relief valves . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Pressure transducer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39Pressure valve does not switch . . . . . . . . . . . . . . . . . . . 108Pressure valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Pressure valves symbols . . . . . . . . . . . . . . . . . . . . . . . . 101Proportional directional valve . . . . . . . . . . . . . . . . . . . . . 80Proportional pressure valve . . . . . . . . . . . . . . . . . . . . . . . 74Proportional throttle and/or flow control valve . . . . . . . . . 79Pump does not convey . . . . . . . . . . . . . . . . . . . . . . . . . 105Pump does not develop any pressure . . . . . . . . . . . . . . 107Pump or motor overheated . . . . . . . . . . . . . . . . . . . . . . 106Pump or motor produce heavy noise . . . . . . . . . . . . . . 106

RRadial piston hydraulic motor . . . . . . . . . . . . . . . . . . . . . 53Radial piston pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45



Radial piston pump with electrohydraulic adjustment . . .48Range D061-7 AND D630-* . . . . . . . . . . . . . . . . . . . . . . .87Relatively high losses . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

SSafety hints for pressure accumulator equipment . . . . . .37Screw type pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42Shaft play too big . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107Shell-and-tube exchangers . . . . . . . . . . . . . . . . . . . . . . .27Short life of highly stressed components . . . . . . . . . . . . .15Shut-off valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59Shut-off valves symbols . . . . . . . . . . . . . . . . . . . . . . . . .100Shuttle valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61Simple check valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59Slide jams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108Slide overheated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109Slide produces heavy noise . . . . . . . . . . . . . . . . . . . . . .109Sliding magnet does not switch . . . . . . . . . . . . . . . . . . .108Slippage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Speed loss on the motor . . . . . . . . . . . . . . . . . . . . . . . .107Start-up of the radial piston variable displacement pump 48Suction filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30Suction pipe with ball valve . . . . . . . . . . . . . . . . . . . . . . .26Surface foam . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20Switching time influence . . . . . . . . . . . . . . . . . . . . . . . . . .67

TTask . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26Task of the filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30Task of the oil reservoir . . . . . . . . . . . . . . . . . . . . . . . . . .22Thermosensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26Three-way flow control valve . . . . . . . . . . . . . . . . . . . . . .79Throttle forms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Throttle valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Two-way flow control valve . . . . . . . . . . . . . . . . . . . . . . .78

UUse of check valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60

VValve does not switch . . . . . . . . . . . . . . . . . . . . . . . . . . .110Valve flutters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109Valve jams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110Valve overheated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110Vane-cell pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41Variable displacement pump . . . . . . . . . . . . . . . . . . . . . .45Variants of the flow rate symbols . . . . . . . . . . . . . . . . . . .56Volume/flow control valves . . . . . . . . . . . . . . . . . . . . . . . .75Volume/flow control valves symbols . . . . . . . . . . . . . . . .102

WWater in the hydraulic fluid . . . . . . . . . . . . . . . . . . . . . . . .19Water in the oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .113


ENGEL AUSTRIA GmbH A 4311 SchwertbergFon: +43.7262.620.0 Fax: +43.7262.620.6009

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