Roles of bearings for different machineries and the way they act

Bearings are machine elements restricting the relative motion of moving parts to only the desired motion.These are designed for offering linear motion to the movable parts of machines or for free rotation around a fixed axis. The bearing can even stop the movement by controlling the effects of normal forces over the moving parts. The classifications of bearings are made as per the directions of the forces applied to the parts, the motions allowed or the type of operation.

For a bearing it is essential to balance the forces and let one part of a machine bear the load of the other. Bearing surfaces are formed or cut into a part with various degrees of control over the size, form, location and roughness of the surface. Manufacturing of the most delicate bearings for sensitive applications needs the latest technology.

The basic movements allowed for bearings are;

1. Linear motions that of drawers
2. Hinge motions like elbow, door and knee
3. Spherical rotation of ball and socket joints
4. Axial rotation of shafts

Friction reduction is the most important factor to keep the bearings function properly for a longer time. The techniques followed for friction reduction in bearings are by utilizing a specific shape, using low surface friction material like plastic, implementing low viscous fluid that prevents two parts of a machine to stay apart and electromagnetic fields that prevent two solid from touching each other.