Bearings are devices used to reduce the friction between two objects in contact with each other in a rotational or translational motion. Leonardo da Vinci had understood the existence of friction and began to study a device similar to a rudimentary bearing.
The bearing is formed by two rings, one internal and one external, and, between the two, the elements that must support the rotating one, reduce the rotation friction, preserve the rotation seat, reduce the danger of dust intrusion, where the balls work, are positioned.
The essential functions are:
– transfer the motion (support and guide components that rotate close to one another)
– transmit forces
Components of a bearing
A bearing typically consists of these components:
– two rings with rolling tracks
– rolling elements (such as rollers or balls)
– cage to keep the rolling elements separate and guide them in the movement
Plain, rolling and ball bearing: how they work
The rolling bearing is an element positioned between a shaft (rotating) and a support (fixed). The rotations between the fixed and mobile part occurs thanks to the presence of rolling elements (spheres, cylindrical or conical rollers); a mechanism based on rolling frictions is generated, which has considerable advantages in terms of efficiency.
In general, rolling bearings are used in rotating or oscillating machines (axles, wheels, trees…) and their task is to transfer the loads between the machine components. They are economical and interchangeable elements which, however, allow high rotation speed and low noise levels.
In turn, they are divided into ball, gears and roller bearings.
Rolling ball bearing
The radial ball bearing is a bearing in which the lead force to support is perpendicular to the axis of rotation. It has a simple structure and can be formed by one or two rows of balls, ideal for operating at high speeds. Self-adjusting radial roller bearings, on the other hand, are formed by two rows of balls anda are used when high rotation between the rings is required.
Just like ball bearings, roller bearings can have one or two crowns and they are used in case the processing requires (almost) absolute precision.
The magnetic bearings are completely free of rolling friction and do not need to be lubricated. These features make them suitable for use also in extreme climatic conditions and, in general, they are the most suitable for improving performance and reliability.