Accuracy and tolerance level of bearings

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



Level 0: Generally used for bearing systems with rotational accuracy exceeding 10 microns, and widely used. For example, the speed control mechanism on ordinary CNC lathes, the cutting mechanism, the speed control mechanism of sedans, the speed control mechanism of large tractors, and the rotating mechanism of ordinary chemical machinery such as motors, centrifugal pumps, and agricultural machinery.



Levels 6 and 5: In precision bearing systems with a rotational accuracy of 5-10 microns or higher speeds, such as commonly used bearings in CNC lathes (front support point level 5, rear support point level 6), finer instruments and equipment, instrument panels and their instruments, instrument panels and precision rotating mechanisms.



Level 4 and Level 2: In super instruments, such as precision coordinate milling machines and transmission gear system software for precision grinding machines, such as instruments, dashboards, and high-speed cameras, the rotational accuracy does not exceed 5 micrometers and the speed is relatively high. The old code for precision level of Chinese bearings.



The norms formulated internationally are generally based on ISO standards and are generally unified with ISO, with some being relatively strict.



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



The previous bearing code regulations in China were: G grade (0), E grade (6), D grade (5), C grade (4), and B grade (2). The current standard code generally adopts German DIN specifications.



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



For example: 6205 and 6205/P5, where the accuracy level of 6205 is P0, only omitted. Let me introduce to you the image of P0 level precision grade bearings.



In addition, bearings with different accuracies are separated differently during the machining process and have different usage values. For example, the usage value of HRB bearings in China has an accuracy of 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.