Angular contact ball bearings

Angular contact ball bearing has high limit rotational speed, they can carry radial load and axial load simultaneously, they can also withstand purely radial load. The axial load carrying capacity depends on the magnitude of contact angle and increases with increasing contact angle.

Structures

1、 Non-separable angular contact ball bearings

This inner ring and outer ring of this type of bearings cannot be separated and comprises following structures:

Contact angle α=15°      counter bore on outer ring, 7000C type

Contact angle α=25°      counter bore on outer ring, 7000AC type

Contact angle α=40°      counter bore on outer ring, 7000B type

2、 Four-point contact ball bearings

This type of bearings is separable bearings. Whereof, QJ0000 type has two-piece inner ring and QJF0000 type has two-piece outer ring. Their contact angles are same as 35°.When received no load or pure radial load, the steel balls of the ball bearing contact with the four points of the rings. When it is received a pure axial load, the steel balls perform a two-point contact with the ring. In addition, besides the axial load from both directions, this kind of bearing can take torque-load as well.

3、 Double row angular contact ball bearings

This kind of bearings can accommodate radial loads as well as axial loads acting in both directions; they can also take loading moment. They can restrain the axial displacement from both directions of the shaft or housing; the contact angle is 30° (or 40°)

Permissible tilt angle

There is only a little inclination between the inner ring and outer ring of angular contact bearings, the permissible tilt angle varies according to the internal clearance when the bearings are operating, the bearing dimensions, internal design, force and loading moment received by the bearings. The value of the maximum permissible tilt angle should be able to ensure that no much extra stress to be generated inside the bearings.

The tilt angle existing between the inner ring and outer ring will influence the bearing service life. Meanwhile, the running accuracy is decreased down and noise increased.

Tolerance and clearance

The tolerances of general angular contact bearings are class normal P0, class P5 and P6. Class P4 and P2 are applicable to machine tool spindles and bearing amount in pairs.

Clearance of single row angular contact bearing is decided by the contact angle, which is guaranteed by manufacturing.

Axial clearance of Four-point contact ball bearings is listed in table 1.

Cage material

Generally, the cage of angular contact bearing is pressed cage of steel sheet or brass cage, and it is solid brass cage for two row angular contact bearing.

Dynamic equivalent radial load

Single-row angular contact ball bearings with a contact angle of 15°

Single bearing or bearing in pairs（7000 C、7000 C/DT）

F_a/F_r≤e         P_r=F_r  

F_a/F_r>e         P_r=0.44F_r+YF_a 

Back-to-back and face to face arrangements（7000 C/DB、7000 C/DF）

F_a/F_r≤e         P_r=F_r+Y₁F_a        

F_a/F_r>e         P_r=0.72F_r+Y₂F_a     

Single-row angler contact ball bearings with a contact angle of 25°

Single bearing or bearing in pairs（7000 AC、7000 AC/DT）

F_a/F_r≤0.68      P_r=F_r              

F_a/F_r>0.68      P_r=0.41F_r+0.87F_a    

Back-to-back and face to face arrangements（7000 AC/DB、7000 AC/DF）

F_a/F_r≤0.68      P_r=F_r+0.92F_a        

F_a/F_r>0.68      P_r=0.67F_r+1.41F_a     

Single-row angular contact ball bearings with a contact angle of 40°

Single bearing or bearing in pairs （7000 B、7000 B/DT）

F_a/F_r≤1.14      P_r=F_r              

F_a/F_r>1.14      P_r=0.35F_r+0.57F_a    

Back-to-back and face to face arrangements（7000 B/DB、7000 B/DF）

F_a/F_r≤1.14      P_r=F_r+0.55F_a       

F_a/F_r>1.14      P_r=0.57F_r+0.93F_a    

Four point contact ball bearings with a contact angle of 35°

F_a/F_r≤0.95      P_r=F_r+0.66F_a       

F_a/F_r>0.95      P_r=0.6F_r+1.07F_a     

Double-row angular contact ball bearings with a contact angle of 45°

F_a/F_r≤1.34      P_r=F_r+0.47F_a       

F_a/F_r>1.34      P_r=0.54F_r+0.81F_a    

Static equivalent radial load

Single-row angular contact ball bearings with a contact angle of 15°

For single bearing or bearing in pairs（7000 C、7000 C/DT）

P_0r=0.5F_r+0.46F_a    

P_0r<F_r  取P_0r=F_r

For back-to-back and face-to-face arrangements （7000 C/DB、7000 C/DF）

P_0r=F_r+0.92F_a

Single-row angular contact ball bearings with contact angle of 25°

For single bearing or bearing in pairs （7000 AC、7000 AC/DT）

P_0r=0.5F_r+0.38F_a   

when P_0r<F_r  let P_0r=F_r

For two bearings in back-to-back and face-to-face arrangements

P_0r=F_r+0.76F_a

Single-row angular contact ball bearings with contact angle of 40°

For single bearing or bearing in pairs

P_0r=0.5F_r+0.26F_a    

when P_0r<F_r  let P_0r=F_r

For two bearings in back-to-back and face-to-face arrangements

P_0r=F_r+0.52F_a

Four point contact ball bearings

P_0r=F_r+0.58F_a

Double-row angular contact ball bearings with contact angle of 45°

P_0r=F_r+0.44F_a

F_r   Actual radial load of the bearing.

F_a   Axial load of the bearing

The values of e 、Y 、Y₁ 、Y₂  see Table 2.