Bearingtype

A bearing is a machine element that constrains relative motion between two parts, typically permitting rotation while reducing friction. Bearings support radial and axial loads and guide movement, usually by using rolling elements or sliding contact, and require lubrication to limit wear and temperature.

Most bearings are classified as rolling bearings, which use balls or rollers to roll between races, or plain (sliding) bearings, which rely on a sliding interface and lubrication.

Rolling bearings include ball bearings and roller bearings. Ball bearings handle moderate radial and axial loads and accommodate higher speeds; common types are deep-groove, angular-contact, self-aligning, and thrust ball bearings.

Roller bearings use cylindrical, needle, spherical, or tapered rollers to carry larger radial loads. They have different performance for misalignment, axial loading, and stiffness; for example, tapered rollers suit combined radial and axial loads, while spherical rollers handle heavy radial loads with some misalignment.

Plain bearings, or bushings, use a sliding interface between surfaces. They employ materials such as bronze alloys, polymers, and composite materials, and rely on lubrication to reduce wear and heat. They are often used for high-load, moderate-speed applications.

Selection considerations include load type and magnitude, speed, alignment, temperature, lubrication, enclosure (sealed versus open), maintenance, and life expectancy. Standardized ratings (dynamic and static load, L10 life) and dimensional codes help ensure interchangeability across manufacturers.