The spherical plain bearing is a kind of spherical sliding bearing. Its sliding contact surface is an inner spherical surface and an outer spherical surface. It can rotate and swing at any angle when it moves. It is made by phosphating, blasting, padding, spraying and other special processing methods. The plain bearing has the characteristics of large load capacity, impact resistance, corrosion resistance, wear resistance, self-aligning and good lubrication.

The structure of the plain bearing is simpler than that of the rolling bearing. It is mainly composed of an inner ring with an outer spherical surface and an outer ring with an inner spherical surface. The plain bearing is generally used in low speed swing motion (i.e. angular motion). Since the sliding surface is spherical, it can also make inclined movement (i.e. centering movement) within a certain angle range. When the supporting shaft and the shaft shell hole are not concentric, they can still work normally.