Bearings

Bearings may be classified broadly according to the motions they allow and according to their principle of operation. common motions include linear/axial and rotary/radial. A linear bearing allows motion along a straight line, for example a drawer being pulled out and pushed in. A rotary bearing or thrust bearing allows motion about a center, such as a wheel on a shaft or a shaft through a housing. Common kinds of rotary motion include both one-direction rotation and oscillation where the motion only goes through part of a revolution. Other kinds of bearings include spherical bearings such as ball joints which are used in car suspensions and some computer mice.