Rolling-element bearing

In mechanical engineering, a rolling-element bearing, also called a rolling bearing, is a bearing that carries a load using rolling parts (such as balls, cylinders, or cones) between two grooved rings called races.ISO 15 The relative motion of the races causes the parts to roll with very little rolling resistance and sliding compared to plain bearings.

 Design types 

 Ball bearing 
A common kind of rolling-element bearing is the ball bearing. Ball bearings have inner and outer races between which balls roll. Each race has a groove, usually shaped so the ball fits and is slightly loose. Ideally, the ball touches the races across a very narrow area. However, a load on an very small point would cause very high pressure. In practice, the ball deforms (flattens) slightly where it touches each race, like how a tire flattens where it touches the road, causing friction and drag.

 Roller bearings 
Roller bearings are the earliest known type of rolling-element bearing. Common roller bearings use cylinders of slightly larger length than their diameter.

 References 

Category:Mechanical engineering