BEARINGS

Bearings are used to allow the rotation of various mechanical parts, such as wheels, pulleys, shafts, axles,...
Bearings can be of the 'sliding' or 'rolling element' type.
Plain bearings have the form of a hollow cylinder and, in some cases, may also be called "plain bearings", "bushings" or "bushings".
This type of bearing is often used when rotation speeds are very high or when a more economical solution than rolling element bearings is possible.
Rolling element bearings typically consist of an inner and outer ring, a shield on each of the two sides and, of course, the rolling elements, which are kept at a suitable distance by a cage.
Rolling element bearings are classified according to
- the direction of the load, which can be radial, axial, combined;
- the shape of the rolling elements, which may be ball, cylindrical roller, tapered roller, barrel or needle roller;
- to the structure, which may be rigid or swivelling.
Bearings can be 'dry', 'lubricated' and 'self-lubricating'.
When it is necessary to create a support for a shaft, it is very useful to choose bearings that can both withstand radial loads and allow for the possible elongation of the shaft due to the expansion and contraction generated by thermal loads.