The old code of bearing accuracy grade code is usually formulated by countries according to ISO standards: usually divided into 0, 6X, 6, 5, 4 and 2. The old codes of bearings in China are: Grade G (Grade 0), Grade E (Grade 6), Grade D (Grade 5), Grade C (Grade 4) and Grade B (Grade 2); The current standard code is based on German specifications, namely, P0, P6, P5, P4 and P2.
P0 level: the rotation accuracy of the bearing system is greater than 10 μ m。 It is widely used in rotating or variable speed mechanisms in general machinery fields such as ordinary machine tools, automobiles, ordinary motors, water pumps, etc.
P6 and P5: can be used when the rotation accuracy is 5-10 μ M or higher rotation speed precision bearing system, such as lathe front and rear support, more precision instruments and meters, precision rotating mechanism and other fields.
P4, P2: used in ultra-precision machinery, can achieve rotation accuracy less than 5 μ M or higher rotation speed, such as precision coordinate boring machine, precision grinding machine gear system, high-speed camera and other precision system applications.
Generally, P0 level will be omitted from the bearing model representation, and the grade code of bearing above P6 level needs to be marked in the bearing model. For example, 6205 and 6205/P56205 bearings are P0.