Bearing machine part is designed to reduce friction between moving parts or to support moving loads. There are various kinds of bearings,such asBall Bearing, Deep Groove Ball Bearing,Miniature Ball Bearing.

Ball bearings are usually found in light precision machinery where high speeds are maintained, friction being reduced by the rolling action of the hard steel balls.Roller bearings are either cylindrical or tapered (conical), depending upon the application; they overcome frictional resistance by a rolling contact and are suited to large, heavy assemblies. In both types the balls or rollers are caged in an angular grooved track, called a race, and the bearings are held in place by a frame, commonly called a pillow block or plummer block. Ball bearings or roller bearings reduce friction more thantextile bearings do. Other advantages of antifriction bearings include ability to operate at high speeds and easy lubrication. A ball bearing usually consists of a split cylindrical shell of hard, strong metal held in a rigid support and an inner cylindrical part of soft metal, which holds a rotating shaft, or journal.

A self-aligning journal bearing has a spherically shaped support that turns in a socket to adjust to movements of the shaft. Slight misalignment of the shaft can be accommodated in the ordinaryball bearing by wearing of the soft bearing material, often an alloy of tin or lead. Less frequently used are aluminum alloys, steel, cast iron, or a thin layer of silver covered with a thin coating of a soft bearing material. Ideally, a film of lubricant, normally oil, separates journal and bearing so that contact is prevented (see lubrication ). Bearings that are not split are called bushings. AGenerator Bearing supports an axial load on a shaft, i.e., a force directed along a shaft's length. It may be a plate at the end of a shaft or a plate against which the collar on the shaft pushes. Large thrust bearings, such as those used to transmit the motive force of a ship's propeller from the shaft to the hull, have blocks that are separated from the collar on the shaft by wedge-shaped spaces filled with oil.

Air Conditioner Bearings are used in high-temperature situations. Certain plastics make satisfactory self-lubricating bearings for low speeds and light loads and, if additionally lubricated, work at higher speeds and carry greater loads. Rubber and a naturally oily wood, lignum vitae, are used in Washing Machine Bearings. Watches and other precision instruments have glass or sapphire pivot bearings. In Vacuum Cleaner Bearingsa film of gas separates the bearings from the moving machine parts. Magnetic bearings employ magnetic repulsion to separate journal from bearing, reducing friction still further.