1. UBC Bearings of America Limited

2. basic
BEARING
knowledge

3. What is a Bearing Used for?
Designed to:
l Reduce friction l Carry loads l Guide moving parts

4. Rolling and Sliding Friction

5. Component parts of a ball bearing
Seal Rolling elements Inner ring Outer ring Cage Seal

6. Seal and Shield Variations
Shields
Low-friction seals
Seals
Seal and Shield Variations
-Z and -2Z
-RZ and -2RZ
-RS and -2RS
Contaminant
exclusion
Silent
running
Grease
retention
Speed
capability

7. Characteristics of Different Seals
Application Shield Seal Need 2Z 2RZ 2RS
Low friction (+) – torque
High speed (+) – ability
Grease retention
Dust exclusion
Water – – + exclusion
Low/high Depends on: Depends on: operating temperature Grease – Grease – Rubber mix
+++ Excellent ++ Good + Fair – Poor

8. Storage Requirements

9. Roller and Ball Raceway Contact

10. Axial and Radial load capability
Combined load Fr
Axial load Fa

11. Spherical roller (symmetrical) Spherical roller (asymmetrical)
Roller Types
Spherical roller (symmetrical)
Spherical roller (asymmetrical)
Ball
Cylindrical roller
Taper roller
Needle roller

12. Ball and Roller Bearing Ranges+
Roller bearings
Ball bearings
Deep groove
Angular contact
Self-aligning
Cylindrical
Taper
Spherical

13. Load Capabilities
Load carrying capacity is expressed as the basic dynamic load rating

14. Ball Bearing Capabilities
Deep groove
Angular contact
Self-aligning
Radial load Axial load Speed Accommodates carrying capacity carrying capacity capability misalignment

15. Function of the Cage
 Prevent immediate contact between rolling elements to minimize friction and heat generation  Guide the rolling elements  Provide space for lubricant  Retain the rolling elements when bearings of separable design are mounted or dismounted

16. Cage Variants
Nylon cage
Steel cage
Solid brass cage

17. + + + + – Nylon Cages Lightweight High elasticity
Good sliding properties +
Good marginal lubrication properties –
Operating temperature < +120 °C

18. + + + + – Steel Cages Lightweight High strength
No operating temperature limit +
High vibration and acceleration resistance –
Sensitive to poor lubrication

19. + + + – Solid Brass Cages Very high strength
Very high vibration and acceleration resistance +
Suitable for very high speed in connection with circulating oil –
Relatively (very) expensive

20. Internal Clearances
Radial clearance
Axial clearance

21. The bearing internal clearance is defined
as the total distance through which one
bearing ring can be moved relative to the
other under zero measuring load.

22. Why Internal clearance?
In order to fit a bearing tightly on a shaft, it is necessary
that the shaft is slightly larger than the bore of the inner
ring. When the bearing is mounted, the inner ring will
be expanded and consequently the space available for
the rolling elements will be reduced. The reduction in
space available for rolling elements when the bearing is
mounted is accommodated by the internal clearance.

23. Why Internal clearance?
Steel will expand with increased temperature. In
operation, the temperature of the various parts of a
bearing will not remain uniform and resulting in
varying degrees of expansion which is compensated
by the internal clearance.

24. Internal Radial Clearance
COLD
Reduced
radial
clearance
Compression
Clearance range C1 Clearance less than C2 C2 Clearance less than Normal C3 Clearance greater than Normal C4 Clearance greater than C3 C5 Clearance greater than C4
Expansion
WARM

25. The internal clearance required is
dependent upon the mounting fit and the operating conditions. In case of doubt, a bearing with greater internal clearance shall always be selected.

26. Effect of Internal Preload and Clearance on Bearing Life
Relative basic rating life L10, %
Preloading
Clearance

27. Correct Fits
Tolerance range for bearings manufactured to ISO

28. Bearing Selection Factors
Available space
Misalignment
Speed
Life
Load/Direction
Operating conditions

29. International Organization for Standardization
ISO Standards
ISO
International Organization for Standardization

30. Diameter Series

31. Relationship: Diameter and Width Series
Diameter Series
Width Series
Height Series

32. Dimension Series
Diameter Series
Width Series

33. Bore designation system
Bore diameter
Written as
Example
Below 10 mm 3 . 9
623
629
10 – 17 mm 10 12 15 17 00 01 02 03
6200
6201
6202
6203
20 – 480 mm 20 25
480 04 05 96
6204
6205
61896
Above 500 mm
710
/710
241/710

34. How the Designation System Works
Bearing types
Radial bearings, width (B, T)
Thrust bearing, height (H)
Outside diameter (D)
Bearing size d/5
(30 mm bore diameter)

35. Tapered Bore Suffixes
Suffix K
Taper 1:12
Suffix K30
Taper 1:30

37. Deep groove ball bearing

38. Self-aligning ball bearing

39. Plane thrust ball bearing

40. Angular contact ball bearing

41. Spherical roller bearing

42. Taper roller bearing

43. Cylindrical roller bearing

44. THE END