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UBC Bearings of America Limited. basic BEARING knowledge.

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Presentation on theme: "UBC Bearings of America Limited. basic BEARING knowledge."— Presentation transcript:

1 UBC Bearings of America Limited

2 basic BEARING knowledge

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

4 Rolling and Sliding Friction µ µ

5 Component parts of a ball bearing SealRolling elementsInner ring Outer ringCageSeal

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

7 ApplicationShieldSeal Need2Z2RZ2RS Low friction+++++(+)– torque High speed+++++(+)– ability Grease retention Dust exclusion Water––+ exclusion Low/highDepends on:Depends on: operating temperatureGrease– Grease – Rubber mix +++ Excellent++ Good+ Fair– Poor Characteristics of Different Seals

8 Storage Requirements

9 Roller and Ball Raceway Contact

10 Axial and Radial load capability Axial load Radial load Combined load FaFa FrFr

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

12 Ball and Roller Bearing Ranges Deep groove Ball bearings Roller bearings + Angular contact Self-aligningCylindricalTaper Spherical

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

14 Ball Bearing Capabilities Deep grooveAngular contactSelf-aligning Radial loadAxial load SpeedAccommodates carrying capacity carrying capacity capabilitymisalignment

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 cageSteel cageSolid 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 + High vibration and acceleration resistance – Sensitive to poor lubrication + No operating temperature limit

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

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 Clearance range C1Clearance less than C2 C2 Clearance less than Normal C3 Clearance greater than Normal C4 Clearance greater than C3 C5 Clearance greater than C4 COLD WARM Reduced radial clearance Expansion Compression

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 L 10, % Preloading Clearance

27 Correct Fits Tolerance range for bearings manufactured to ISO

28 Operating conditions Available spaceMisalignment SpeedLife Load/Direction Bearing Selection Factors

29 International Organization for Standardization ISO ISO Standards

30 Diameter Series

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

32 Dimension Series Width Series Diameter Series

33 Bore diameter Written asExample Below 10 mm – 17 mm – 480 mm Above 500 mm 710/710241/710 Bore designation system

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 Suffix K30 Taper 1:12 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


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