The thrust ball bearing is designed to bear the thrust load when running at high speed.It consists of a gasket ring with a raceway with ball rolling.Because the ring is cushion shaped, the thrust ball bearing is divided into two types: flat base cushion and centering spherical cushion.In addition, the bearing can withstand axial load, but not radial load.Thrust ball bearings divided into two type： unidirectional and bidirectional. The unidirectional thrust ball bearing consists of two rings (shaft ring and bearing seat ring) and a cage with a ball.The bidirectional thrust ball bearing is composed of three rings and two retainers with balls.If it is bidirectional, it takes the form of two retainers containing the ball clamping the shaft ring.