The thrust ball bearings, belonging to separate type bearings, fall into one-way thrust ball bearings and two-way thrust ball bearings according to their structures. A one-way thrust ball bearing can bear an axial load in one direction, while a two-way thrust ball bearing can bear axial loads in two directions. Neither the one-way thrust ball bearing nor the two-way thrust ball bearing can bear a radial load. The thrust ball bearing also has a structure with a seat pad. Since the installation surface of the seat pad is spherical, the bearing has a self-aligning function and is capable of reducing the impact caused by installation error. The thrust ball bearing is mainly applied to automatable and machine tool industries.prs4atlive.cn