How to distinguish between ordinary bearings and precision bearings?

Precision bearings are divided into P0, P6, P5, P4 and P2 according to the grading standard of ISO. The grades increase successively, in which P0 is ordinary precision and other grades are precision grades. Of course, different classification standards and different types of bearings have different classification methods, but the significance is one to one. The performance of precision bearing requires the rotating body to have high runout accuracy, high-speed rotation and small friction and friction change.
Precision bearings and ordinary bearings should be distinguished from each other from the following points:
1. The dimensional requirements are different, and the dimensional deviation (inner diameter, outer diameter, ellipse, etc.) of products with high accuracy grade is smaller than that of products with low accuracy grade;
2. The required values of rotation accuracy are different. The rotation accuracy of products with high accuracy grade (inner diameter runout, outer diameter runout, end to raceway runout, etc.) is stricter than that of products with low accuracy grade;
3. The required values of surface shape and surface quality are different. The surface shape and surface quality (surface roughness, circular deviation, groove shape deviation, etc.) of products with high accuracy grade are stricter than those of products with low accuracy grade;
4. The material properties of products with particularly high accuracy grade are more favorable than those of products with general accuracy grade.