There are raceways on the inner and outer rings of angular contact ball bearings, and the inner and outer rings can make relative displacement along the axial direction of the bearing. This kind of bearing is especially suitable for bearing compound load, that is, radial and axial loads acting simultaneously. The bearing capacity of angular contact ball bearing increases with the increase of contact angle α. The contact angle is the angle between the contact line of the ball and raceway in the radial plane and the vertical line of the bearing axis.