Rolling bearings

Although the term "rolling placenta" seems universally understandable, few of us are aware of the widespread use of this type of equipment in the automotive industry and the variety of their construction. By virtue of its universality and (Relative) simplicity can be used anywhere, where we want to effectively support the rotating shaft and reduce the friction forces occurring in this assembly. Here a small digression: the rolling bearing does not necessarily have to be associated with the rotational movement of the shaft. Linear bearings are also used – for example, in seat guides.
The main advantage of a rolling bearing is the rolling friction present in it, resulting from the rolling of balls and rollers on treadmills. The resistance produced by such a bearing is small and increases more slowly as the load increases than in plain bearing, where the mating parts are separated by a thin layer of oil film. The coefficient of friction of rolling bearings is 0,0008-0,0025. Despite the low friction, they have a fairly clear limit of permissible loads, significantly smaller than plain bearings. After exceeding it, we are still dealing with the same nature of friction, but rolling rollers or balls causes treadmill deformation, which destroys the bearings in a short time. These are micro-deformations of the raceway and roller surfaces, which result in peeling of their surface.
An important advantage of rolling bearings is their trouble-free lubrication. Even highly loaded rolling bearing arrangements do not require pressure lubrication, unlike plain bearings, in which it is necessary to form a layer of grease, separating mating surfaces. Rolling bearings generally operate in constant contact with mating surfaces, between which there is a slight slip causing a friction force. Therefore, the rolling bearing must be lubricated. Greater slippage occurs especially in bearings, whose task is to carry both loads perpendicular to the shaft axis, as well as parallel to it. These are primarily all kinds of ball bearings, which always have some ability to carry axial loads. Roller tapered roller bearings and special ball bearings are used to handle loose axial loads, e.g.. double-row – Angular contact. They are commonly used for bearing the hubs of the running wheels, where the direction of loads often changes. Simple roller bearings, on the other hand, not carrying any axial forces, they can withstand very high loads perpendicular to the shaft axis. They are used in the nodes of the transmission mechanisms.
The double row ball bearing has a fairly simple design and allows you to carry heavy loads transversely and axialally. The baskets of modern bearings are also made of plastic.
The running wheel hub is a classic place for the use of a double row angular contact ball bearing, filled with grease and equipped with fixed seals.
In cheap designs, similar open bearings are sometimes found.