Precision bearings and ordinary bearings
Precision bearings are classified according to the ISO classification standards: P0, P6, P5, P4, P2. The grades are increased in order, P0 is ordinary precision, and other grades are precision grades. It should be distinguished from ordinary bearings from the following points:
1. The size requirements are different. The products with high accuracy grades (precision bearings) have smaller dimensional deviations (inner diameter, outer diameter, ellipse, etc.) than the products with lower accuracy grades.
2. The requirements of rotation accuracy are not the same. Products with high accuracy grades have a higher rotation accuracy (inner radial runout, outer radial runout, runout of the end face to the raceway, etc.) than products with lower accuracy grades.
3. The required values of surface shape and surface quality are different. Products with high accuracy grades(precision bearings) have stricter surface shapes and surface qualities than those with lower accuracy grades.
4. The material of products with particularly high accuracy grades has better material performance than the products of general accuracy grades.