The key to the tolerance level of the bearing is to determine the rotation accuracy of the shaft to the support point.

Level 0: It is generally used for bearing systems with rotation accuracy exceeding 10 microns, which is very common. For example, the speed regulating mechanism and the tool feeding mechanism of ordinary CNC lathes, the speed regulating mechanism of cars, the speed regulating mechanism of large tractors, the rotating mechanism of general chemical machinery such as motors, centrifugal pumps and agricultural machinery.

Level 6, Level 5: In precision bearing systems with rotation accuracy of 5-10 microns or high speed, such as commonly used bearings for CNC lathes (front support point 5, rear support point 6), finer instruments and instruments Panels and their instruments, instrument panels and precision rotating mechanisms.

Level 4, Level 2: In ultra-instruments, such as precision coordinate milling machines, precision grinding machine transmission gear system software, such as instruments, dashboards and high-speed cameras, the rotation accuracy is not more than 5 microns, and the speed is relatively high. The old code name of China Bearing's precision grade code.

The norms formulated internationally are all formulated in accordance with ISO standards, generally unified with ISO, and some are relatively strict.

Accuracy is divided into gauge accuracy and rotational accuracy. Divided into 0 degrees, 6X degrees, 6 degrees, 5 degrees, 4 degrees, 2 degrees.

In China, the previous bearing code regulations are: G grade (0), E grade (6), D grade (5), C grade (4), B grade (2). The current standard code generally adopts the German DIN specification.

(a) P0(0), P6(6), P5(5), P4(4), P2(2) level(2). The general specification grade P0 is omitted when it is reflected in the bearing model specification. Only for P6 or above grade, the grade code appears in the bearing model specification.

For example: 6205 and 6205/P5, the accuracy level of 6205 is P0, which is just omitted. Let me introduce to you in this way, the P0 grade is the image of non-precision grade bearings.

In addition, bearings of various precisions have different separations during processing, and also have different use values. For example: the use value of China's HRB bearings, the accuracy is 1.5 times that of P6, 2 times that of P5, 2 times that of P4, 2 times that of P5, and 2.5 times that of P5.