Bearing terminology
Date:2022-10-21 Editor:Oukai Bearing

Some frequently used bearing terms are explained here. 


Symbols used in this catalogue are mainly in accordance with ISO standards. The most common symbols are given in fig. 1 and fig. 2.。


fig. 1 - Symbols for boundary dimensions - radial bearings             

fig. 2 - Symbols for boundary dimensions - thrust bearings

d Bore diameter
D Outside diameter
B Bearing width
H Bearing height
r Chamfer dimension
α Contact angle

Shaft-bearing-housing system

fig. 3 - Terminology - Shaft-bearing-housing system

1.Cylindrical roller bearing

2.Four-point contact ball bearing



5.Shaft abutment shoulder

6.Shaft diameter

7.Shaft seat

8.End plate

9.Radial shaft seal

10.Seal wear ring

11.Housing bore diameter

12.Housing seat

13.Housing cover

14.Snap ring

Radial bearings

    fig. 4 - Terminology - Radial bearing

fig. 5 - Terminology - Radial bearing

1.Inner ring

2.Outer ring

3.Rolling element: ball, cylindrical roller, needle roller, tapered roller, spherical roller, toroidal roller


5.Capping device

   Seal – made of elastomer

   Shield – made of sheet steel

6.Outer ring outside surface

7.Inner ring bore

8.Inner ring shoulder surface

9.Outer ring shoulder surface

10.Snap ring groove

11.Snap ring

12.Outer ring side face

13.Recess for capping device

14.Outer ring raceway

15.Outer ring raceway

16.Recess for capping device

17.Inner ring side face


19.Bearing pitch circle diameter

20.Total bearing width

21.Guide flange

23.Retaining flange

23.Contact angle

Thrust bearings

fig. 6 - Terminology - Thrust bearing

24.Shaft washer

25.Rolling element and cage assembly

26.Housing washer

27.Housing washer with a sphered seat surface

28.Seat washer

Contact us
Shandong Oukai Bearing Manufacturing Co.,Ltd


Phone:150 9506 6919


Address:Yandian Industry Park, Linqing City, Shandong Province