Joint bearing is a kind of special structure of the sliding bearing, its structure is better than rolling bearing structure is simple, its mainly by a spherical within the inner ring and a spherical outer ring, can bear larger load, according to its different types and structure, can bear radial load and axial load or the joint of the radial, axial load. Commonly used in the motion of the low speed movement (i.e., angular motion), due to the sliding surface of spherical shape, can also be within the scope of the Angle do tilt motion (that is, the heart movement), the supporting shaft and shaft shell hole concentricity is bigger, can still work normally.