The key to bearing tolerance grade is to determine the rotation accuracy of the shaft to the support point.
Class 0: Used in bearing systems with rotational accuracy over 10 microns. Very common.For example, the general CNC lathe governing mechanism, cutting mechanism, car governing mechanism, large tractor governing mechanism, common chemical machinery such as motor, centrifugal pump and agricultural machinery rotating mechanism.
Level 6, level 5: in the precision bearing system with rotating accuracy of 5-10 microns or high speed, such as CNC lathe commonly used bearings (front support point 5 level, back support point 6 level), fine instruments and equipment, instrument panel and its instruments, instrument panel and precision rotating mechanism.
Class 4, class 2: in super instrumentation, such as precision milling machine, precision grinding machine gear system software, such as instrumentation, instrument panel and high speed camera, rotation accuracy is not more than 5 microns, high speed.Chinese bearings before the old code precision class code.
International standards are formulated in accordance with the ISO standard to develop, are generally unified with ISO, some are more strict.
Accuracy is divided into specification accuracy and rotary accuracy.It's 0 degrees, 6X degrees, 6 degrees, 5 degrees, 4 degrees, 2 degrees.
The previous bearing codes in China are: G class (0),E class (6),D class (5),C class (4),B class (2).The current standard code generally adopts the German DIN specification.
(a) P0 (0), P6 (6), P5 (5), P4 (4), P2 (rank 2), (2).The general specification grade P0 is omitted in the bearing model specification, and only the grade code of P6 or P6 above appears in the bearing model specification.
Examples are 6205 and 6205/P5, where the accuracy level of 6205 is P0, but omitted.In this way, I will introduce to you the image of P0 level bearings.
In addition, the separation of bearings of various precision is different in the processing process, and the use value is also different.For example: the use value of Chinese 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.