Joint bearing is a special structure of the sliding bearing. Its structure is simpler than the Rolling by an inner and outer one within the sphere of spherical, can withstand a larger load, according to their different types and structures that can withstand the radial load, shaft to load or radial, axial joint load at the same time. Generally used for the lower speed of the swing motion (ie angular motion) for the spherical shape due to the sliding surface, or in a certain angle in the range of tilt movement (aligning movement) degree in the supporting shaft and the shaft shell holes of different heart than large, still work properly. Joint under the direction of the load bearing according to their capacity of nominal contact angle and structure can be divided into radial spherical plain bearing angular contact bearing joints. Thrust spherical plain bearings and rod end joint bearing radial spherical plain bearing (GE-type) the nominal contact angle of 0 degrees, suitable for radial load and smaller axial load. angular Contact Spherical Plain Bearings (GAC type) was divided into angular contact spherical plain bearings and angular contact thrust joint bearing two angular contact Spherical Plain Bearings nominal contact angle greater than 0 degrees but less than or equal to 30 degrees to adapt to withstand the radial and axial load, while the role of joint load; angular contact thrust joint bearing the nominal contact angle greater than 30 degrees less than 90 suitable for axial load can also be combined loads, but the radial load is not greater than 0.5 times the axial load, thrust spherical plain bearings (GX), the nominal contact angle of 90 degrees, suitable for axial to the load, can not withstand the radial load. rod end bearings suitable to withstand the radial load smaller axial load (generally less than or equal to 0.2 times the radial load). joint bearings lubricated and self-lubricating type.