A sleeve bearing is a kind of cylindrical bearing. It got its name from having a single internal rotating cylinder inside it. Sleeve bearings are porous, so they draw up the oil applied on the outer sleeve. Sleeve bearings are a kind of plain bearing --that is, bearings with few moving parts.

Sleeve bearings (sometimes called bushings, journal bearings or plain bearings) facilitate linear movement between two parts. Sleeve bearings consist of a metal, plastic or fiber-reinforced composite sleeves that reduce vibrations and noise by absorbing friction between two moving parts using a sliding motion.A sleeve bearing is a type of plain bearing that can handle high loads and velocities. Sleeve bearings help make engines run smoothly and quietly. These durable and long lasting bearings can also perform well in other high-load, high-velocity applications, such as machines and turbines.