Plain bearing is a kind of sliding bearing with special structure.

Its structure is simpler than that of rolling bearing. It is mainly composed of an inner ring with outer sphere and an outer ring with inner sphere. It can bear large load. According to its different types and structures, it can bear radial load, axial load or combined load with radial and axial at the same time. It is generally used for low-speed swing motion (i.e. angular motion). Since the sliding surface is spherical, it can also make inclined motion (i.e. centering motion) within a certain angle range. It can still work normally when the non concentricity between the support shaft and the shaft shell hole is large.