What Are Bearings Used For?

Its role should be support, that is, literal interpretation used to bear the shaft, but this is only a part of its role, support its essence is able to bear radial load. You can also understand that it's used to fix the axis. It is fixed axis so that it can only achieve rotation, and control its axial and radial movement. Bearing the role of a support role, namely if the transmission parts (such as: shaft) directly cooperate with hole, a driving resistance is big, and the wear big, transmission is not easy to change, and bearing is rely on rolling contact between components to support the transmission parts, so the sliding resistance is small, less power consumption, starting easily, etc.

Bearing is an important part of modern mechanical equipment.
Its role should be support, that is, literal interpretation used to bear the shaft, but this is only a part of its role, support its essence is able to bear radial load.  You can also understand that it's used to fix the axis.  It is fixed axis so that it can only achieve rotation, and control its axial and radial movement.
Bearing the role of a support role, namely if the transmission parts (such as: shaft) directly cooperate with hole, a driving resistance is big, and the wear big, transmission is not easy to change, and bearing is rely on rolling contact between components to support the transmission parts, so the sliding resistance is small, less power consumption, starting easily, etc.
The main function is to support the mechanical rotating body, reduce its friction coefficient in the process of movement, and ensure its rotation accuracy.  It can be understood that it is used to fix the axis, so that it can only achieve rotation, and control its axial and radial movement.  If the shaft has no bearings it will not work at all.  Because the axis can move in any direction, and the work requires that the axis can only rotate.
Bearings are widely used in automobiles: rear wheels, transmission, electrical components.
Electrical: general motors, household appliances.  Instrumentation, internal combustion engine, construction machinery, railway rolling stock, loading and unloading machinery, various industrial machinery.  Machine tool spindles, agricultural machinery, high frequency motors, steam turbines, centrifuges, small car front wheels, differential pinion shafts.
Oil pump, Roots blower, air compressor, all kinds of transmission, fuel injection pump, printing machinery, motor, generator, internal combustion engine, steam turbine, machine tool spindle, reducer, loading, unloading and handling machinery, all kinds of industrial machinery, etc.  Almost as long as it is rotating rotating are used to bearings.
Bearing parameters
Life
Under a certain load, the number of revolutions or hours that the bearing experiences before pitting corrosion is called the bearing life.
The life of a rolling bearing is defined in revolutions (or hours of operation at a given speed) : a bearing within this life shall have initial fatigue damage (spalling or defect) on any of its bearing rings or rolling bodies.  However, whether in laboratory tests or in actual use, it can be obviously seen that the actual life of bearings with the same appearance under the same working conditions is very different.  In addition, there are several different definitions of bearing "life", one of which is the so-called "working life", which means that the actual life of a bearing can be achieved before damage is caused by wear, damage is usually not caused by fatigue, but by wear, corrosion, seal damage and other reasons.
Due to the difference in manufacturing accuracy and material uniformity, even if the same material and the same size of the same batch of bearings are used under the same working conditions, their service life is not the same.  If the statistical life is 1 unit, the longest relative life is 4 units, the shortest is 0.1-0.2 units, and the ratio between the longest and the shortest life is 20-40 times.  90% of bearings do not produce pitting corrosion, and the number of revolutions or hours experienced is called the bearing rated life.