Seminar presentation on PRACTICAL tRAINING: Submitted in the partial fulfillment of Bachelor of Technology degree Of the Rajasthan Technical University, Kota.

1A presentationOn

NATIONAL BEARING COMPANY

CHIRAG JOSHIBYContentsAbout NBCIntroduction to BearingTypes of BearingBall BearingConstruction of Ball BearingManufacturing Process of Ball BearingFeatures of Ball BearingsTypes of Load and Load EquationsApplications of Ball Bearings22Company ProfileNBC Bearings is the product of National Engineering Industries Limited (NEI), a part of the CK Birla Group, which manufactures a wide range of bearings for the automotive, industrial and railways

NEI manufactures bearings in about 1000 different sizes

It has the capacity to develop bearings from 10 mm bore to 2000 mm outer diameter.

NBCs current capacity is to make 100 million bearings annually across its three plants (Jaipur, Newai, Manesar). NEI aims to double the production capacity in next seven years3Introduction to BearingsThe term "bearing" is derived from the verb "to bear"; a bearing being a machine element that allows one part to bear (i.e., to support) another

A bearing is a machine element that constrains relative motion to only the desired motion, and reduces friction between moving parts

Objective of bearing is to provide relative positioning and rotational freedom while transmitting a load between two parts.

It needs a good support to ensure stability and frictionless rotation.4Types of Bearing5

Ball BearingTapered Roller BearingCylindrical Roller BearingSpherical Rolling BearingBall BearingA ball bearing is a most common type of rolling-element bearing that uses balls to maintain the separation between the bearing races

Precision Ball Bearings from 6 mm bore to 75 mm bore diameter are manufactured in NBC

This Division is spread over a covered area of 14,694 Sq. Meters

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Tapered Roller BearingCan take large axial forces as well as being able to sustain large radial forces.

Based on the observation that cones that meet at a point can roll over each other without slipping.

Generally separable, which means the cone assembly, consisting of the inner ring with roller and cage

Precision Ball Bearings from 17 mm bore to 100 mm bore diameter are manufactured in NBC

7Tapered Roller Bearing Cont.

8Cylindrical Roller BearingHave a high radial load capacity and are suitable for high speeds

Precision Ball Bearings from 20 mm bore to 75 mm bore diameter are manufactured in NBC

Cylindrical bearings provide the highest possible radial load capacity compared to other roller bearing types9Spherical Roller BearingSpherical roller bearings are self-aligning bearings designed for heavy radial loading.

Precision Ball Bearings from 50 mm bore to 200 mm bore diameter are manufactured in NBC

A spherical roller bearing is a rolling-element bearing that permits rotation with low friction, and permits angular misalignment10Assembling of Ball Bearing11

Rolling vs. Sliding Friction

12Manufacturing Process13Ball forgingTube extrusionHeat Treatment Ball manufacturingRace Grinding AssemblyFinished goodsWarehouse &Shipping Bought out componentTurning Another method of producing metal spheres is by forging them in a mold. A work piece is cut from stock and placed in the die. The die are forced together, forging the metal ball, causing it to take the spherical shape of the die cavity. Balls are finished and polished, before they are ready for their particular application.Extrusionis a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section.13Manufacturing Process Cont.CARBURIZATIONCarburizing is a is a heat treatment process in which iron or steel absorbs carbon liberated when the metal is heated in the presence of a carbon bearing material, such as charcoal or carbon monoxide, with the intent of making the metal harder.The carburizing is performed 940 to 980c in rotary hearth furnace with time of 10hrs. But carburizing is done for only cup and cone with Air: LPG =10:1 (Endo Gas).14Manufacturing Process Cont.QUENCHINGQuenching is a process of cooling a metal at a rapid rate. This is most often done to produce a marterialistic transformation. In ferrous alloys, this will often produce a harder metal, while non-ferrous alloys will usually become softer than normal.In NBC Oil is used in the quenching process and the oil is kept at a temperature of 250C. Agitator is used to stir the oil in the oil quenching tank.15Manufacturing Process Cont.16

Stress RelivingInteresting FactsIf you were to file down onto a ball bearing, you would wear out the file before you would wear out the bearing!If you were to expand a 1-inch ball to equal the size of planet Earth, the ball would be rounder than the actual EarthThe Hubble telescope, weather satellites and even the Mars Space Rover all use bearings.When using outer race rotation, you are reducing your bearing lifespan by 20%70% of bearing failures are from improper lubrication17Features of Ball BearingCan be used under wide range of temperature

Internationally available and available.

Maintenance, replacement, inspection are easy

Cheap

Have great rigidity and are robust18Applications of Ball Bearing19In horology, the company Jean Lassale designed a watch movement that used ball bearings to reduce the thickness of the movement

Aerospace bearings are used in many applications on commercial, private and military aircraft including pulleys, gearboxes and jet engine shafts

Skateboard wheels each contain two bearings, which are subject to both axial and radial time-varying loadsTypes of Bearing LoadBearings typically have to deal with two types of load:Radial LoadAxial Load (Thrust)

RADIAL LOAD act at right angles to the shaft (bearing's axis of rotation)

AXIAL LOAD (Thrust) acts parallel to the axis of rotation.20

Types Of Bearing Load Cont.

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The bearings in theelectric motor and thepulleypictured above face only a radial load. In this case, most of the load comes from the tension in the belt connecting the two pulleys.The bearing above is like the one in a barstool. It is loaded purely in thrust, and the entire load comes from the weight of the person sitting on the stool.The bearing above is like the one in the hub of your car wheel. This bearing has to support both a radial load and a thrust load. The radial load comes from the weight of the car, the thrust load comes from the cornering forces when you go around a turn.Load EquationsRelative axial load = (Fa/ZDw )

Fa = Axial ForceZ = Number of ballsDw = Ball Diameter

Relative radial load = (MF/R)

M = TorqueR = Radius F = Load Connection Factor

22F = Load Connection FactorSingle Chain Drive1.00Timing Belt Drive1.10Spur, Helical Gear1.25Double Chain Drive1.25V-Belt Drive1.50Flat Belt Drive2.50Please note that different manufacturers calculate radial capacities at different speeds and different shaft locations. Typically, capacities increase at lower speeds and reduce at higher speeds22Thank You23