The key to bearing tolerance level is to determine the rotation accuracy of the shaft to the supporting point.
Level 0: Generally used for bearing systems with a rotation accuracy of more than 10 microns, and is very common. For example, the speed regulation mechanism of ordinary CNC lathes, the knife mechanism, the speed regulation mechanism of cars, the speed regulation mechanism of large tractors, the rotation mechanism 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 5, rear support point 6), finer equipment and meters Panel and its instruments, instrument panel and precision rotating mechanism.
Level 4, Level 2: In ultra-instruments, such as precision coordinate milling machines, gear system software for precision grinding machines, such as instruments, dashboards and high-speed cameras, the rotation accuracy is not more than 5 microns, and the speed is relatively high. Accuracy grade code of the old code of China Bearing.
Internationally formulated specifications are formulated in accordance with ISO standards, and are generally unified with ISO, and some are relatively strict.
The accuracy is divided into specification accuracy and rotation accuracy. Divided into 0 degree, 6X degree, 6 degree, 5 degree, 4 degree, 2 degree.
The previous bearing code regulations in China are: G-level (0), E-level (6), D-level (5), C-level (4), and B-level (2). The current standard codes generally adopt German DIN specifications.
(a) P0(0), P6(6), P5(5), P4(4), P2(2) level(2). The general specification grade P0 is omitted if it is reflected in the bearing model specification. Only the P6 or above grade, the grade code appears in the bearing model specification.
For example: 6205 and 6205/P5, where the accuracy level of 6205 is P0, but it is omitted. In this way, I would like to introduce to you that the P0 grade is the image of non-precision grade bearings.
In addition, bearings of various precisions are separated differently during processing, and their use values are also different. 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 of P4, 2 times of P5, and 2.5 times of P5.