1
Caged Technology
TechnicalReference
Smooth Silent Ecological
®
CATALOG No.268-9E
For details, visit THK at www.thk.com*Product information is updated regularly on the THK website.
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Caged TechnologyIntroduction
Since ball bearings in the initial stage of development were not provided with a cage, they produced highlevels of noise, had a short service life and were unable to be used at high rotating speeds.
Later, caged ball bearings were developed that exhibited low noise levels even at high rotating speeds.In addition, these caged ball bearings were able to demonstrate long service life despite the number of
balls being fewer than full ball types, and evolved significantly so that they were able to be used in a widerange of applications.
THK, the first manufacturer in the world to develop the LM Guide, has developed its LM Guide with CagedBall Technology that is able to achieve a dramatic improvement in performance over conventional products.The LM Guide with Caged Ball Technology delivers a long service life and excellent high-speed performance inthe same manner as roller bearings, while also eliminating maintenance for a long period of time.
Initial Stage of Development (Full Ball Type)
• Metal contact between balls caused a shortage of grease life.• Short service life
Current Bearings (Caged Ball Type)• Grease is held by the cage for excellent lubrication.• No metal contact between balls for extended service life.• No metal contact between balls suppresses generation of heat.• No metal contact between balls eliminates ball collision noise.• Balls exhibit orderly movement for smooth operation.
Rotary Bearings
Case of the LM Guide
Balls
Friction occurs between balls resulting in the generation of collision noise
Oil film contact
Absence of friction between balls eliminates the generation of collision noise for quiet operation
Without caged ball
With caged ball
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Structure of the LM Guide with Ball Cage
LM block
LM rail
End plate
End seal
Ball
Ball cage
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Collision noise
Collision noiseDirection of travel
Mutual friction
Absence of collision noise between balls
Generation of collision noise between balls
Since metal contact occurs only at the load zone, metal noise is held to a minimum.
Conventional type (without
ball cage) circulating path
In the case of the full ball type, the balls demonstrate skewing and move randomly.
Ball cage type circulating path
Ball cage
Balls are guided by the ball cage so as to be uniformly aligned in the direction of circulation for smooth operation.
1 Quiet Operation that Minimizes Metal ContactCollision noise between balls is eliminated by the ball cageresulting in quiet operation.
Advantageof Caged Ball
2 Orderly Ball MovementSince the balls are held by the ball cage in the form of a belt, theyare aligned uniformly and move in a circulating manner. There isno skewing of the balls, while sudden variations in friction are alsoeliminated, allowing for stable movement.
Advantageof Caged Ball
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4
3 Original Cage Structure Exhibiting ExcellentHigh-Speed PerformanceThe use of ball cages eliminates generation of heat caused byfriction between balls result ing in excellent high-speedperformance.
Advantageof Caged Ball
4 Grease Holding Structure (Consecutive Grease Pockets)for Long-Term, Maintenance-Free Operation, LongService LifeGrease pockets are provided consecutively over the entire ballcirculation path to constantly lubricate the balls enabling long-term,maintenance-free operation, Long Service Life.
Advantageof Caged Ball
Contact state between balls and ball cage State at turning sections
Ball cage
Grease retention status after travel (SHS45LV: load endurance test)
Grease pockets are provided throughout the ball cage.
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The Caged Ball not only allows the LM guide to be run for a long time period free ofmaintenance, but also significantly improves the service life of the system. As described below,a performed service life test has offered data about this improvement.
Data on LM Guide with Caged Ball
Service life test for LM Guide1. Testing instrumentation
2. Testing parametersModel : SHS25V1SS+580LP / HSR25A1UU+580LPNumber of pieces : 32Load : 11.1 kN per LM block (0.35 C of SHS25V)Lubricant : Lithium soap base grease No. 2, Only initial lubrication
Load P
Load cell
Table Stroke
LM railLM block
Spring
Plate
Acceleration: 1 G
Cycle
Time (seconds)
Spe
ed (
m/m
in)
Stroke=350mm
0.250.1
60
0.40.1
Improved Service Life
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6
3. Test results
Comparison in terms of dynamic durability values (C)and service life (L)
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The results of the performed test indicate that the dynamic durability values of the LM guideimplemented by Caged Technology are higher than of the conventional LM guide.
2-2. Status of Remaining Grease after the Durability Test
Ball cage before running
Remaining grease is observed in the ball cage.
Ball cage after running 8,000 km(Test stop)
CalculationExample
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■Rolling Resistance DataThe use of a ball cage enables the balls to be uniformly aligned, eliminatingcrowding of the balls that occurs when they enter the block. As a result, smoothand stable movement can be obtained in all forms of installation, and fluctuationsin rolling resistance are reduced for the realization of high accuracy.
00
50 100 150 200 250 300 350 400
2
4
6
8
10
12
14
16
18
20
Stroke (mm)
Rol
ling
resi
stan
ce v
alue
(N
)
Results of Measuring Fluctuations in Rolling Resistance of SHS25LV (with ball cage)
(feeding speed: 10 mm/sec)
00
50 100 150 200 250 300 350 400
2
4
6
8
10
12
14
16
18
20
Stroke (mm)
Rol
ling
resi
stan
ce v
alue
(N
)
Results of Measuring Fluctuations in Rolling Resistance of HSR25LR (without ball cage)
(feeding speed: 10 mm/sec)
7
■Noise Level DataThe use of a ball cage eliminates interference between balls resulting in lownoise levels.
LM Guide with Caged Ball Technology
Comparison of Noise LevelsBetween the SHS35LV and HSR35LR
(speed: 50 m/min)
Frequency (Hz)
0
10
20
30
40
0 2,000 4,000 6,000 8,000 10,000 12,000 14,000
Noi
se le
vel (
dBA
)
HSR35LR
SHS35LV
(without ball cage)
(with ball cage)
50
30
40
50
60
70
90
80
0 25 50 75 100 125
Noi
se le
vel (
dBA
)
Comparison of Noise LevelsBetween the SHS35LV and HSR35LR
speed (m/min)
HSR35LR
9.6dBA
SHS35LV
(without ball cage)
(with ball cage)
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■Low Generation of DustThe use of a ball cage eliminates friction between balls resulting in acorresponding decrease in the generation of metal wear fragments foroutstanding effects against prevention of the generation of dust.
00
100
200
300
5 10 15 20
Am
ount
of d
ust g
ener
ated
(par
ticle
s/2
min
-lite
r)
Time (hours)
SSR20 (with ball cage)
00
100
2 00
300
5 10 15 20
Am
ount
of d
ust g
ener
ated
(par
ticle
s/2
min
-lite
r)
Time (hours)
Conventional products (without ball cage)
0.3 – 0.50.5 – 1.01.0 – 2.0
2.0 – 5.05.0 –
Particle size (μm)
■High-Speed Durability Test ResultsSince the use of a ball cage eliminates friction between balls, there is lessgeneration of heat making it possible to demonstrate excellent high-speedoperation.
Grease was stillpresent and therewere no abnormalitiesobserved in the ballsor grease.
Detailed drawing of ball cage
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Sample : SHS65LVSSSpeed : 200 m/minStroke : 2500 mmLubrication : Initial injection of
grease onlyLoad : 34.5 kNAcceleration : 1.5 G
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Structure of the typeSRG/SRN/SRW
LM rail
LM block
End plate
End seal
Roller cage
Roller
Rollercage
Standard Part Block Diagram
Roller cage (roller)retaining parts
Type SRG Type SRN Type SRW4545°°
4545°°4545°°
4545°°
Caged Roller Technology
SRG/SRN/SRW
Cross-sectional view
Enlarged view of circulating paths
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Features of the typeSRG/SRN/SRW
Prevents roller skewing
The use of a roller cage allows the rollers to circulatewhile uniformly aligned, preventing skewing whenentering block load area, and reducing variation inroll ing resistance to obtain stable and smoothmovement.
Long-Term,Maintenance-Free Operation
The use of a roller cage eliminates friction betweenrollers, and retains lubricant in the grease pocketsbetween adjacent rollers, ensuring the required amountof lubricating oil is supplied to the curved contactsurfaces of the spacers and rollers of the circulatingpath to realize long-term maintenance-free operation.
Ultra-HighRigidity
Ultra-high rigidity is achieved by using rollers having alow degree of elastic deformation for the roll ingelements and an optimized roller diameter and length.Also, each row of rollers is arranged at a 45° contactangle so that an equal load rating is applied in fourdirections (radial, reverse radial, and lateral directions).
Global StandardDimensions
The dimensional design complies with the Type HSRdeveloped by THK as the pioneer of linear motionsystems and has become the global standard.
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LM Guide with Caged Roller Technology
0
10
20
30
40
50
60
0 100 200 300 400 500
Stroke (mm)
SRG45LC2.26N
Full-roller type roller guide# 45
10.63N
Rol
ling
resi
stan
ce (
N)
Sample) : SRG45LCC0
Conditions) : Pre-loading : C0 clearanceSpeed : 180 m/minAcceleration : 1.5 GStroke : 2300 mmLubricant : Initial injection of
grease only
• Intermediate results:No abnormalities during 15,000 km oftravel
flaking or insufficientgrease was not observed( )
Nodiscolorationof grease isobserved.
Detailed drawing of roller cage
Adequate greaseremains
Roller
Rollers
Roller Cage
■Rolling Resistance Value DataThe use of a roller cage eliminates friction between rollers while also enabling therollers to circulate while uniformly aligned. As a result, there is reducedoccurrence of skewing allowing stable movement.
■Durability DataThe use of a roller cage enables grease to be retained in the space betweenadjacent rollers, realizing long-term, maintenance-free operation by inhibiting theescape of grease from the circulating path.
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■Rigidity valuesRadial clearance SRG : Clearance C0
Conventional roller guide : Equivalent to C0
0
2
4
6
8
10
12
0 5 10 15 20 25 30
Conventional roller guide#45
SRG45LC (with roller cage)
Radial load (kN)
Dis
plac
emen
t (μm
)
0
5
10
15
20
0 5 10 15 20 25 30
Conventional roller guide#45
SRG45LC (with roller cage)
Reverse Radial load (kN)
Dis
plac
emen
t (μ
m)
Lateral load (kN)
0
10
20
30
40
0 5 10 15 20 25 30
Conventional roller guide#45
SRG45LC (with roller cage)
Dis
plac
emen
t (μm
)
Fixed table bolt Unfixed bolt (free movement)
Radial rigidity
Reverse radial rigidity
Lateral rigidity
Radial clearance
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Structure of the typeSBK
Ball Screw with Ball Cage
SBN/SBK/SBKN/SDA/HBN/SBKH
Ball cage
End cap
Two-raceway,large-leadscrew shaft
BallsBall screw nut
13
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Features of the typeSBK
Low Noise, Acceptable Running SoundUse of a ball cage allows balls to be evenly spaced and
eliminates collision noise between balls. In addition, ballsare picked up in the tangential direction, which alsocontributes to eliminating collision noise. As a result, lownoise and acceptable running sound are achieved.
Long-term Maintenance-free OperationThe formation of grease pockets increases grease retention
and achieves long-term maintenance-free operation. Inaddition, even in adverse environments (e.g., coolant, foreignmatter), this model ensures long-term maintenance-freeoperation when attached with an optional wiper ring or a QZLubricator*.(*: For wiper ring and QZ Lubricator, contact THK.)
Excellent Sliding PropertiesBall cages arranged between balls eliminate mutual friction of
the balls and significantly improve torque characteristics. Pre-load dynamic torque fluctuations are also reduced allowing theobtaining of excellent sliding properties.
High-speed OperationBecause of its circulation structure where the end caps enable the balls to be picked up in the
tangential direction and the lead angle direction, this model is capable of high-speed operation ata DN value of 160,000, achieving high-speed feed 2.2 times faster than the conventional model.
Point (metal) contact
Oil film contactGrease pockets
Ball cage structure
Conventional structure
Locations of grease pockets
Balls circulate in the tangential direction Balls circulate in the lead angle direction
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Improved Service Life
■Service life testService life test under a high speed (free of maintenance)
Testing instrumentation for a long-period high-speed test was used to test model SBK withlubrication system QZ. The operating cycles were run under a DN value of 160,000 andwith only initial lubrication carried out.
Running distance (km)0 1,000 2,000 3,000 4,000 5,000
The test results on 3,000-km of running performance show that the lubricant film neither peels off nor is broken.
Sample tested
Number of samples
Maximum rotation speed
Stroke
Lubricant
Grease quantity
Applied load
Acceleration
SBK3620-7.6
3
4200 min-1(DN value : 160,000)
400 mm
Multemp HRL grease (initial lubrication only)
8 cm3
1.87 kN (preload only)
1G
Conditions
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Ball Screw with Caged Ball Technology
0 500 1,000 1,500
Shaft rotational speed (min-1)
2,000 2,500 3,000 3,500
60
50
40
30
20
AFG greaseTHK general-purpose grease
Sat
urat
ion
tem
pera
ture
out
side
nut
(°C
)
ItemShaft diameter/lead
Shaft rotational speed
Stroke
Lubricant
Description32 / 10 mm
400-3000 min-1
400 mm AFG grease THK general-purpose grease
Shaft rotational speed (min-1)
Conventional type(without ball cage)
SBN type
80
70
60
50
0 1,000 2,000 3,000 4,000
Noi
se le
vel (
dBA
)
ItemShaft diameter/lead
Lubricant
Measuring distance
Description32 / 10 mm
AFG grease1 m
ItemShaft diameter/lead
Speed
Shaft rotational speed
Stroke
Lubricant
Description32 / 10 mm
10 mm/s60 min-1
700 mmMobil Vactra No. 2 oil
-1.0
-0.5
0.0
0.5
1.0
0 25 50 75 100 125 150
Conventional type(without ball cage)SBN TYPE
Time(s)
Tor
que(
N-m
)
■Torque Fluctuations and Sliding PropertiesThe ball cage reduces torque fluctuations enabling excellent constant speedcharacteristics to be obtained even at low speed for a high degree of positioning accuracy.
■Noise Level DataThe use of a ball cage reduces friction between balls to realize low noise levels.
■Heat Generation DataAlthough the use of a ball cage eliminates friction between balls making it possible todemonstrate low levels of heat generation and outstanding high-speed operation, the use ofTHK AFG grease (low heat-generation grease) suppresses heat generation even more.
Conditions
Conditions
Conditions
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Global Standard
Conveyance systemNC latheMachining center
FPD manufacturing machineDrilling machine
Semiconductor manufacturing machineOptical stageMedical equipment
FPD manufacturing machinePrinterChip mounter
Semiconductor manu-facturing machineConveyance system
FPD manufacturingmachineChip mounter
Caged Ball LM Guides
A Lineup of Caged Ball/Roller LM Systems
Conveyance systemFPD manufacturing machineMedical equipment
Semiconductor manu-facturing machineChip mounter
For Machine Tools/Highly dust-proof
ModelModelRadial Type
Model
Wide, Low Gravity Center Type
ModelLightweight, Compact
Model
Finite Stroke
Semiconductor manu-facturing machineInspection equipment
Medical equipmentIndustrial machinery
Machining centerNC lathe
Five-axis milling machineGrinding machine
Cross Type
Precision alignment stageWire-cut electric discharge machineXY table
Optical measuringinstrumentBonding machine
Model
Model
17
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with Superb Features S Series
Ball Screws with Ball Cage
Compact Ball Screw
High-speed laser cuttingmachineHigh-speed chip mounter
High-speed conveyance systemHigh-speed printed board drilling machine
Caged Roller LM Guides
ModelSRGSuper-ultra-high Rigidity Type
Machining centerUltra precision latheHeavy cutting machine
Five-axis millingmachineDrilling machine
Super-ultra-high Rigidity, Low Gravity Center Type
ModelSRN
Machining centerUltra precision latheHeavy cutting machine
Five-axis millingmachineDrilling machine
ModelSRWSuper-ultra-high Rigidity, Wide Type
Plano millerLarge pressingmachine
Large five-face millingmachineInjection molding machine
High Speed Ball Screw
Model
Model
High-speed machining centerHigh-speed chip mounter
High-speed conveyance systemHigh-speed printed boarddrilling machine
High Speed Ball Screw
ModelSBK
High-speed machining centerHigh-speed chip mounter
High-speed conveyance systemHigh-speed printed boarddrilling machine
High Load Ball Screw
ModelHBN
Injection moldingmachineDie-casting machine
Extrusion moldingmachinePressing machine
SDAHigh-Load, High-Speed Ball Screw
Injection molding machineBlow molding machineExtrusion molding machine
Pressing machineDie-casting machine
ModelSBKH
High Speed Double-Nut Ball Screw
ModelSBKN
High-speed machining centerHigh-speed chip mounter
High-speed conveyance systemHigh-speed printed boarddrilling machine
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● The photo may differ slightly in appearance from the actual product. ● The appearance and specifications of the product are subject to change without notice. Contact THK before placing an order.● Although great care has been taken in the production of this catalog, THK will not take any responsibility for damage resulting from typographical errors or omissions.● For the export of our products or technologies and for the sale for exports, THK in principle complies with the foreign exchange law and the Foreign Exchange
and Foreign Trade Control Law as well as other relevant laws.For export of THK products as single items, contact THK in advance.
● “LM GUIDE”and “ ” are the registered trademarks of the THK CO., LTD.®
All rights reserved
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