The angular contact ball bearing is divided into angular contact ball bearing double row angular contact ball bearing and four-point contact ball bearing. It can bear radial and axial loads at the same time and can bear pure axial load as well with higher limiting speeds. The capability of bearing axial load is determined by the degree of contact angle. The bigger the contact angle is, the bigger the axial load can be borne. The contact angles are classified as 15 2 5 40″ When the bearing bears the radial load, the additional axial force will occur. Therefore, a relefore a relevant axial load in the opposite direction must be applied. The bearings should be used in pairs in general. In connection with mountage in pairs, there are three kinds of mountages, namely back to back face to face and in series