Thrust bearing is a special kind of sliding bearing, which is a double-row cylindrical roller bearing composed of a pair of intermeshing bearing parts. Thrust bearings have a simple structure and do not require lubrication or sealing to prevent pollution and corrosion. They are suitable for occasions that bear large shaft loads without high-speed rotation. Thrust bearings are divided into thrust ball bearings and thrust roller bearings.

Thrust ball bearings are mainly composed of a bearing housing and a set of spherical rollers. The inner ring has two spherical rolling bodies, which are respectively installed on the two sides of the bearing seat, and the rollers are connected with the raceway on the other end through the inner ring. The bearing housing is one of two cylindrical holes bolted to the base, on which a rotatable bolt is mounted. The cylindrical hole is cylindrical and has a certain distance relative to the two spherical rolling elements, which is the largest gap between the bearing seat and the spherical rolling elements. The spherical roller is composed of a raceway with a thread or gear connecting the spherical rolling body and in contact with the other end surface, and corresponds to the inner ring. ) instead of truncated cone (or "convex spherical").

Thrust roller bearings are designed to meet the requirements of heavy loads and high loads, and have the characteristics of light weight, large load capacity, small friction coefficient, and wide temperature range. Under heavy load, low speed or light load, it can maintain radial load without axial movement, and can bear large axial load. Thrust bearings are widely used in various machinery such as machine tool spindles, internal combustion engine cylinders, ships, and automobile engines. Thrust bearings are quite common in modern machine tools - often multiple thrust bearings with two or three rollers can be used in machining centers etc.