The industry produces different types of bearings today. They are used in many mechanisms. The main function of any bearing is to reduce friction between structural parts.
Plain bearings
Many machines have rotating parts in their design. These can be various levers, wheels and drums. Some of them are firmly attached to the shaft and rotate with it, transferring movement to other parts of the mechanism. Others rotate freely on their axes.
Friction arises between the rotating parts, which prevents the free rotation of the parts of the mechanism. Friction can play a positive role, for example, it is thanks to friction that the brake can work. But it must be borne in mind that friction can lead to negative consequences.
When rubbing, the metal heats up, parts wear out, which often leads to breakdowns. To avoid this, dry friction is replaced by rolling friction or liquid sliding friction. Bearings are special bearings, the use of which allows you to remove dry friction.
All bearings are divided into two large groups: plain bearings and rolling bearings. The design of plain bearings consists of a split housing and bushings or a housing with a hole and a bushing pressed into it. Parts subject to friction are always produced from different materials. For example, the bushings are made of bronze, and the shafts are made of ferrous metals. This technique can significantly reduce friction.
In addition, special grooves are laid on the inner surface of the liners. Grease spreads over them, which, when the shaft rotates, forms an oil film that lifts the shaft. It no longer touches the surfaces of the liners; dry friction is replaced by liquid friction.
Rolling bearings
The main function of rolling bearings is to overcome friction. Rollers or steel balls installed in bearings roll along the grooves of the rings placed between the rotating shaft and the fixed support. This allows friction to be effectively overcome.
In order to choose the right bearings, it is necessary to take into account which unit of the machine they will be installed on. When starting off, use rolling bearings. But it is not recommended to install sleeve bearings in this case - they do not work well when starting off.
Ball bearings are installed in conventional electric motors; in the car, the axle shafts of the front wheels are supported by ball bearings, the crankshaft is supported by plain bearings.
Needle bearings are installed on mechanisms that experience powerful loads. Such a bearing starts to work like a roller bearing, and when the shaft speed increases, the needles stop rolling. Together with the oil, they form an inner ring that slides between the bearing rings. The needle roller bearing combines all the advantages of rolling and plain bearings.
