Spherical plain bearing

Spherical plain bearings are sliding bearings with a spherical contact surface: an inner ring with a convex outer surface slides in an outer ring with a concave spherical bore. They carry very high static and shock loads while accommodating angular movement and misalignment between shaft and housing. Maintenance-type versions with steel-on-steel sliding contact require regular relubrication; maintenance-free versions use liners such as PTFE fabric. Radial types are most common, complemented by thrust and angular contact designs. Typical applications include hydraulic cylinder mountings, linkages, and construction and agricultural machinery — generally locations with oscillating rather than rotating motion.