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July 2012 Bearing Basic KnowledgeSlide 1
Bearing Basic Knowledge
PT Schaeffler Bearings Indonesia
July 2012 Bearing Basic KnowledgeSlide 2
Bearing basic knowledge …
-Bearing types and selection-Bearing internal clearance- Selection of bearing cages-Bearing designation-Bearing tolerance-Shaft and housing tolerances
Training Topics
July 2012 Bearing Basic KnowledgeSlide 3
Fischer
Aktien
Gesellschaft
The Beginning of FAG
The first ever steel ball grindingmachine invented by a Germanengineer in 1883.
July 2012 Bearing Basic KnowledgeSlide 4
Once upon a time…
Introduction to Rolling Bearings
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July 2012 Bearing Basic KnowledgeSlide 5
Sliding Friction Rolling Friction
Introduction to Rolling Bearings
July 2012 Bearing Basic KnowledgeSlide 6
Introduction to Rolling Bearings
Outer ring
Inner ring
Rollingelement
Cage
Lubricant !!
July 2012 Bearing Basic KnowledgeSlide 7
Bearings whichare non-seperable
Bearings whichare seperable
Bearing Characteristic s
July 2012 Bearing Basic KnowledgeSlide 8
Bearings that can take"dynamic misalignment"
Bearings that can take"static misali gnment"
Bearing Characteristics
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July 2012 Bearing Basic KnowledgeSlide 9
Ball
Barrel roller
Tapered roller Cylindrical roller
Needle roller
UnsymmetricalBarrel roller
Bearing Characteristic s
July 2012 Bearing Basic KnowledgeSlide 10
Line contact(more contact)
Roller Bearings
Higher loadLower speed
Point contact(less contact)
Ball Bearings
Lower loadHigher speed
Bearing Characteristics
July 2012 Bearing Basic KnowledgeSlide 11
POINT contact …
Deep groove ball bearing: 6310Dimensions = d x D x B = 50 x 110 x 27Static load rating = C 0 = 38 kNLimiting speed = n G = 14000 rpm
LINE contact …
Cylindrical roller bearing: NU310Dimensions = d x D x B = 50 x 110 x 27Static load rating = C 0 = 113 kNLimiting speed = n G = 6300 rpm
Bearing Characteristic s
July 2012 Bearing Basic KnowledgeSlide 12
F r
F a
F r F r
F a
"Radial bearings" designedto take the radial force
"Axial bearings" designed
to take the axial force
Bearing Characteristic s
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July 2012 Bearing Basic KnowledgeSlide 13
Contact lineRadial plane
Radial bearing has …the contact angle < 45 degrees
Axial bearing has …the contact angle > 45 degrees
Bearing Characteristics
Nominal contact angle is an angle
between the bearing radial plane andthe contact line without any applied load.
July 2012 Bearing Basic KnowledgeSlide 14
Radialball bearings
Radialroller bearings
Axial roller bearings Axial ball bearings
Bearing Characteristics
July 2012 Bearing Basic KnowledgeSlide 15
Small misalignmentHigh speed
• Pumps• Shipbuilding• Machine tools• Road vehicles• Railway vehicles• Paper machinery• Power transmission
• Electrical machinery• Conveying equipment• Agricultural machinery• Household appliances• Steelworks and rolling mill• Food and delicacies industry• Mining and construction• Ventilation engineering
Designation 6XXXe.g. 6208, 6310
Deep Groove Ball Bearing
July 2012 Bearing Basic KnowledgeSlide 16
Suffix 2ZShieldGap Seal
Suffix 2RSRSealContact Seal
Prevent dust and dirt Good Good
Prevent water and moisture Bad Good
Applications with outer ring rotating Bad Good
Limiting speed (of the same size) Higher Lower
Deep Groove Ball Bearing
The sealed bearing is already filled with STANDARD grease
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July 2012 Bearing Basic KnowledgeSlide 17
Video !!
Deep Groove Ball Bearing
July 2012 Bearing Basic KnowledgeSlide 18
• Pumps• Machine tools• Road vehicles• Power transmission• Electrical machinery• Conveying equipment• Ventilation engineering• Steelworks and rolling mill
Small misalignmentHigh speed
Designation 7XXXe.g. 7205, 7306
Angular Con tac t Bal l Bear ing
July 2012 Bearing Basic KnowledgeSlide 19
O arrangement(Back to Back, DB)
X arrangement(Face to Face, DF)
Tandem arrangement(Tandem, DT)
Ang ular Con tac t Bal l Bear ing
July 2012 Bearing Basic KnowledgeSlide 20
O arrangement(Back to Back, DB)
X arrangement(Face to Face, DF)
Angular Con tac t Bal l Bear ing
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July 2012 Bearing Basic KnowledgeSlide 21
• Paper machinery• Conveying equipment• Agricultural machinery• Ventilation engineering• Mining and construction• Food and delicacies industry
Misalignment 4ºHigh speed
Designation 1XXX, 2XXXe.g. 1207, 2210
Self Alignin g Ball Bearing
July 2012 Bearing Basic KnowledgeSlide 22
No misalignmentHigh speed
Designation 51XXXe.g. 51120, 51330
Designation 52XXXe.g. 52220, 52330
Axi al Bal l Bear ing
July 2012 Bearing Basic KnowledgeSlide 23
• Pumps• Crushers• Centrifuges• Machine tools• Road vehicles• Paper machinery• Railway vehicles• Vibrating machinery• Power transmission• Electrical machinery• Conveying equipment• Household appliances• Ventilation engineering• Mining and construction• Steelworks and rolling mill
Designation NXXX, NXXXXe.g. N308, NU328, NU2226
Cylindrical Roller Bearing
July 2012 Bearing Basic KnowledgeSlide 24
SLNU N NUPNJSmall misalignment
Low speedSmall misalignment
Very low speed
Cylindrical Roller Bearing
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July 2012 Bearing Basic KnowledgeSlide 25
Needle Roller Bearing
Small misalignmentLow speed
Without rings K…e.g. K20X26X12, K24X30X17
With rings NA…e.g. NA4907, NA6906
July 2012 Bearing Basic KnowledgeSlide 26
Application examples …
Brake pedal Acceleration pedal Automotive gearbox
Needle Roller Bearing
July 2012 Bearing Basic KnowledgeSlide 27
Misalignment 3ºLow speed
• Pumps• Crushers• Shipbuilding• Wind turbines• Road vehicles• Railway vehicles
• Paper machinery• Vibrating screens• Power transmission• Drum belt conveyors• Conveying equipment• Agricultural machinery• Ventilation engineering• Mining and construction• Steelworks and rolling mill
Designation 2XXXXe.g. 23020, 22250
Spherical Roller Bearing
July 2012 Bearing Basic KnowledgeSlide 28
• Pumps• Crushers• Wind turbines• Machine tools
• Road vehicles• Railway vehicles• Power transmission• Conveying equipment• Agricultural machinery• Tunnel boring machinery• Steelworks and rolling mill
Small MisalignmentLow speed
Designation 3XXXXe.g. 32210, 32215
Tapered Roller Bearing
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July 2012 Bearing Basic KnowledgeSlide 29
O arrangement(Back to Back, DB)
X arrangement(Face to Face, DF)
Tapered Roller Bearing
July 2012 Bearing Basic KnowledgeSlide 30
No misalignmentLow speed
Designation 8XXXXe.g. 81107, 89312
Axi al Cyl indri cal Ro ll er Bear ing
July 2012 Bearing Basic KnowledgeSlide 31
• Extruders
• Gearboxes• Generators• Palm oil mills• Paper machines• Boats and ships
Misalignment 3ºLow speed
Designation 29XXXe.g. 29220, 29468
Axi al Sph eri cal Ro ll er Bear ing
July 2012 Bearing Basic KnowledgeSlide 32
Bearing Selection
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July 2012 Bearing Basic KnowledgeSlide 33
Radial clearance Axial clearance
C2CNC3C4C5
S r
S a
Bearing Internal Clearance
July 2012 Bearing Basic KnowledgeSlide 34
D
d
ST
Internal clearance is for…
1. Expansion and contraction of the inner and outer r ing due totight fits.
2. Thermal expansion from heatgenerated during operation, butthe key valueis the temperaturedi ff erence between the inner and outer ring, not how high thetemperature.
- Clearance before mounting
- Clearance after mounting
- Operating clearance
Bearing Internal Clearance
July 2012 Bearing Basic KnowledgeSlide 35
C1 Clearance smaller than C2C2 Clearance smaller than CNCN Clearance normal (no suffix)
C3 Clearance bigger than CNC4 Clearance bigger than C3C5 Clearance bigger than C4
Clearance class specified by following suffixes …
Example: 6205 (CN), 6309-C3, NU230-E-M1-C4
If the recommended shaft and housing tolerances are fulfilled.The normal operating clearance is achieved with clearance
CN, in larger bearings, predominantly with C3.
Bearing Internal Clearance
July 2012 Bearing Basic KnowledgeSlide 36
Example: Bearing 6310 has internal clearance 6-23 microns
Bearing 6310-C3 has internal clearance 18-36 microns
See HR1 page 215
Bearing Internal Clearance
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July 2012 Bearing Basic KnowledgeSlide 37
6309-2Z used to replace 6309-2Z-C3 in an e-motor, jammed in 1 month.
- Insufficient operating clearance results in hot running and seizing
- Excessive operating cl earance results in high vibration / low accuracy.
Bearing Internal Clearance
July 2012 Bearing Basic KnowledgeSlide 38
0+
Temperature Difference
Tight Fits
CN / C3 / C4
Bearing Internal Clearance
July 2012 Bearing Basic KnowledgeSlide 39
Tolerance class specified by following suffixes …
Example: 6208 (PN), 7310-P5, 6309-P63 etc.
For an application which requireshigh accuracy or very high speed
Tolerances of Standard Bearings
PN Precision Normal (no suffix)
P6 Precision better than PNP5 Precision better than P6
P4 Precision better than P5
P2 Precision better than P4
July 2012 Bearing Basic KnowledgeSlide 40
Example:Inner diameter of 6220 is between 99.980 - 100.000 mmInner diameter of 6220-P6 is between 99.985 - 100.000 mm
From HR1 page 122Tolerance class PN
From HR1 page 124Tolerance class P6
Tolerances of Standard Bearings
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July 2012 Bearing Basic KnowledgeSlide 41
Cage functions-To separate rolling elements-To keep a pitch between rolling elements-To hold rolling elements within a bearing-To guide rolling elements to the raceway
Cage - Functions
July 2012 Bearing Basic KnowledgeSlide 42
Cage - Guidance
Rolling element guide
(no additional suffix)Normal applications
Inner ring guide
(with suffix B)High vibration
High speed
Outer ring guide
(with suffix A)High vibration
High speed
July 2012 Bearing Basic KnowledgeSlide 43
Window typed cage for anangular contact ball bearing
Window typed cage fora cylindrical roller bearing
Cage - Moulded Plastic Cage (Polyamide)
July 2012 Bearing Basic KnowledgeSlide 44
Ribbon type cagefor a ball bearing
Riveted cagefor a ball bearing
Window typed cagefor an spherical
roller bearing
Cage - Pressed Steel Cage
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July 2012 Bearing Basic KnowledgeSlide 45
Riveted cagefor a ball bearing
Window typed cagefor a ball bearing
Riveted cagefor a cylindricalroller bearing
Cage - Machined Brass Cage
July 2012 Bearing Basic KnowledgeSlide 46
Criterion Steel Brass Polyamide
Weight Good Bad Very Good
Strength Very Good Very Good Good
Cost / Price Good Bad Good
Space for lubricant Very Good Good Good
Running noise Good Good Very Good
Corosion fromchemical / lubricant
Very Good Good Bad
Temperature morethan 120 degrees C
Good Good Bad
Cage – Selection
1. The plastic cage has its own advantages for weight, noise, and flexibility2. Strength comparison between two metallic cages i.e. steel and br ass cage3. Brass cage has emergency running behavior, easy to machine with accuracy4. New bearings are with pressed steel cage, machined brass cage is expensive
July 2012 Bearing Basic KnowledgeSlide 47
DGBB OD240 mm is dimensionally stable up to 200 degrees
ACBB OD240 mm is dimensionally stable up to 200 degrees
SABB every sizes is dimensionally stable up to 150 degrees
Bearing with a plastic cage (polyamide) can stand up to 120 degreesBearing with rubber seal and standard grease can stand up to 100 degrees
Maximum Operating Temperature
Max operating temperature of standard BALL bearings …
July 2012 Bearing Basic KnowledgeSlide 48
CRB every sizes is dimensionally stable up to 120 degreesSRB every sizes is dimensionally stable up to 200 degreesTRB every sizes is dimensionally stable up to 120 degreesNRB every sizes is dimensionally stable up to 120 degrees
Max operating temperature of standard ROLLER bearings …
Bearing with a plastic cage (polyamide) can stand up to 120 degreesBearing with rubber seal and standard grease can stand up to 100 degrees
Maximum Operating Temperature
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July 2012 Bearing Basic KnowledgeSlide 49
Bearing designation can tell you …
1. Bearing type2. Dimensions3. Part tolerances4. Bearing clearance5. Cage design and material6. Other special characteristics
Bearing Designation
July 2012 Bearing Basic KnowledgeSlide 50
Bearing designation
Prefix SuffixBase designation
Bearingtype
Widthseries
Diameter series
Borecode
Bearing Designation
July 2012 Bearing Basic KnowledgeSlide 51
The first digit specify the bearing type …
1XXX Self aligning ball bearing2XXXX Spherical roller bearing3XXXX Tapered roller bearing5XXXX Axial ball bearing6XXX Deep groove ball bearing7XXX Angular contact ball bearing8XXXX Axial cylindrical roller bearingNXXXX Cylindrical roller bearing
Bearing Designation
July 2012 Bearing Basic KnowledgeSlide 52
The last one or two digits is the bore code
Bore code
3 to 90001020304...96/500/530
Bore diameter
3 to 9 mm10 mm12 mm15 mm17 mm20 mm...480 mm500 mm530 mm
Bore code X5
Bearing Designation
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July 2012 Bearing Basic KnowledgeSlide 53
One or two digits in the middle are width and diameter series
00
0 1 2 3 4 0 1 2 3 0 1 2 3 0 2
2404332313033222120240302010 Wi dt h s er ies Wi dt h s er ies Wi dt h s er ie s Wi dt h s eri es
Dim. series Dim. series Dim. series Dim. series
02
34
Bearing Designation
Example:Spherical roller bearing with designation 23220 is WIDER than 22220Spherical roller bearing with designation 22320 is BIGGER than 22220
July 2012 Bearing Basic KnowledgeSlide 54
62066 = Deep groove ball bearing
(0) = Width series 02 = Diameter series 206 = 06 x 5 = 30 mm bore
7305-B7 = Angular contact ball bearing(0) = Width series 03 = Diameter series 305 = 05 x 5 = 25 mm bore
Bearing Designation
July 2012 Bearing Basic KnowledgeSlide 55
30209-A3 = Tapered roller bearing0 = Width series 02 = Diameter series 2
09 = 09 x 5 = 45 mm bore
NU2314-ENU = Cylindrical roller bearing2 = Width series 23 = Diameter series 314 = 14 x 5 = 70 mm bore
Bearing Designation
July 2012 Bearing Basic KnowledgeSlide 56
See HR1 page 148
One bearing has 2 ringsinner and outer ring.
There are 2 load cases,circumferential load andpoint load.
Shaft and Housin g Tolerances
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July 2012 Bearing Basic KnowledgeSlide 57
Inner ring rotates
Outer ring stationaryLoad direction constant
IR - Circumferential load(tight fit necessary)
OR - Point l oad(loose fit permissible)
Example:Shaft weightRoll pressSee HR1 page 148
Shaft and Housin g TolerancesSchematic 1
July 2012 Bearing Basic KnowledgeSlide 58
Shaft and Housin g TolerancesSchematic 2
Inner ring stationaryOuter ring rotatesLoad direction constant
IR - Point load(loose fit permissible)
OR -Circumferential load(tight fit necessary)
ExampleCar hub bearing
See HR1 page 148
July 2012 Bearing Basic KnowledgeSlide 59
Shaft and Housin g TolerancesSchematic 3
Inner ring rotatesOuter ring stationaryLoad direction rotates
IR - Point load(loose fit permissible)
OR - Circumferential load(tight fit necessary)
ExampleCentrifugesVibrating screensSee HR1 page 148
July 2012 Bearing Basic KnowledgeSlide 60
Shaft and Housin g TolerancesSchematic 4
Inner ring stationaryOuter ring rotatesLoad direction rotates
IR - Circumferential load(tight fit necessary)
OR - Point l oad(loose fit permissible)
ExampleHub bearing with unbalanceSee HR1 page 148
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July 2012 Bearing Basic KnowledgeSlide 61
See HR1 page 149
Shaft and Housing Tolerances
- Meaning of tight fit- Meaning of loose fit- Meaning of transition fit- Difference betweencapital and small letter
July 2012 Bearing Basic KnowledgeSlide 62
Example: 6212 in e-motor, recommended shaft fit is 60 k6
From HR1 page 150 …
Shaft and Housin g Tolerances
July 2012 Bearing Basic KnowledgeSlide 63
From HR1 page 155 …
Example: shaft fit 60 k6, shaft tolerance is +2 / +21 i.e. 60.002 – 60.021 mm
Shaft and Housin g Tolerances
July 2012 Bearing Basic KnowledgeSlide 64
" Thank you for you r attention "
PT Schaeffler Bearings IndonesiaGedung Graha Pena Suite 707Jl. A Yani no 88Surabaya - 60234Phone : 0318270030Fax : 0318270030