This bearing is a separate structure, mainly to withstand axial load, but also bear certain radial load and thrust ball bearings can withstand greater than the axial force, that is, when a shell axis and tilt despite normal work. By rolling the body shape can be divided into symmetrical and asymmetrical type two, as the friction symmetrical, the work area is small, so be gradually phased out. Non-symmetrical will be promoting the use of.