As long as the diameter of the inner ring of the bearing is detected to see if its tolerance is within 3 μ, the diameter of the outer ring is also detected in this way.

If not, it can basically be concluded that it is made in China. Generally, about 8 microns made in China is normal, and the roundness is not much better.

Bearing is an important part of modern mechanical equipment. Its main function is to support the mechanical rotating body, reduce the friction coefficient during its movement and ensure its rotation accuracy.

According to the different friction properties of moving elements, bearings can be divided into rolling bearings and sliding bearings. Among them, rolling bearing has been standardized and serialized, but compared with sliding bearing, its radial size, vibration and noise are larger and its price is higher.

Generally speaking, rolling bearing consists of four parts: outer ring, inner ring, rolling body and cage. Strictly speaking, it consists of six parts: outer ring, inner ring, roller, cage, seal and lubricating oil. It can be defined as a rolling bearing mainly composed of an outer ring, an inner ring and rolling bodies. According to the shape of rolling elements, rolling bearings are divided into two categories: ball bearings and roller bearings.