The key to the bearing tolerance level is determined based on the requirements for the rotation accuracy of the shaft to the support point.
Level 0: Generally used for bearing systems with rotation accuracy exceeding 10 microns, and is widely used. For example, the speed regulating mechanism of ordinary CNC lathes, the tool feeding mechanism, the speed regulating mechanism of cars, the speed regulating mechanism of large tractors, and the rotating mechanisms of ordinary chemical machinery such as motors, centrifugal pumps and agricultural machinery.
Level 6, Level 5: In precision bearing systems with a rotation accuracy of 5-10 microns or higher speeds, such as commonly used bearings for CNC lathes (front support point level 5, rear support point level 6), finer instruments and meters Panels and their instruments, instrument panels and precision rotating mechanisms.
Level 4, Level 2: In super instruments, such as precision coordinate milling machines, transmission gear systems of precision grinding machines, such as instruments, dashboards and high-speed cameras, the rotation accuracy does not exceed 5 microns and the rotation speed is relatively high. The old code of Chinese bearings is the accuracy grade code.
Internationally formulated specifications are all formulated in accordance with ISO standards. They are generally consistent with ISO, and some are 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: Grade G (0), Grade E (6), Grade D (5), Grade C (4), Grade B (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 reflected in the bearing model specifications. Only for grades P6 or above, the grade code appears in the bearing model specifications.
For example: 6205 and 6205/P5, where the accuracy level of 6205 is P0, but it is omitted. Let me introduce to you that P0 level is the image of non-precision level bearings.
In addition, bearings of various precisions are separated differently during the processing process and have different use values. 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.
