1. The "axis" and supporting parts of rotation that reduce friction will definitely experience friction. Bearings are used between the rotating "shaft" and the rotating support part.
Bearings can reduce friction, make rotation smoother, and reduce energy consumption. This is the maximum function of bearings.
2. There will be a significant force between the "axis" that protects the rotation support part and the rotation support part. Bearings can prevent damage to the rotating support part due to this force, keeping the rotating "shaft" in the correct position. It is precisely because of these functions of bearings that the machine can be used repeatedly for a long time.
The purpose of bearings in automobiles: rear wheels, transmissions, electrical components. Electrical: General electric motors, household appliances. Instruments, internal combustion engines, construction machinery, railway vehicles, loading and unloading machinery, various industrial machinery. Machine tool spindle, agricultural machinery, high-frequency motor, gas turbine, centrifugal separator, small car front wheel, differential pinion shaft.