The accuracy of bearings is divided into two types: dimensional accuracy and rotational accuracy.
Dimensional accuracy refers to the items required when the bearing is installed on the shaft or bearing box, including the inherent dimensional accuracy of the inner diameter, outer diameter, width, assembly height, chamfer size, etc. Rotation accuracy refers to the specified vibration during rotation, including the allowable values of radial and axial vibration of the inner ring and outer ring.
Bearing accuracy levels range from ordinary accuracy levels to Level 6, Level 5, Level 4 and Level 2 of JIS B 1514 (accuracy of rolling bearings), and the accuracy increases in order.
Bearing accuracy grade classification:
The accuracy grades of bearings from low to high are P0, P6, P5, P4, and P2.
Countries around the world usually refer to ISO standards. The old code standards for Chinese bearings were G level (corresponding to level 0), E level (corresponding to level 6), D level (corresponding to level 5), C level (corresponding to level 4), B level (corresponding to level 4). level 2). Current code names usually use German DIN standards, such as 6208 and 6208/P5. The accuracy level of 6208 is P0 level, but it is omitted in daily expressions.
Among these accuracy levels, level 0 is suitable for bearing systems with rotational precision greater than 10 μm, such as the transmission mechanisms of ordinary machine tools, feed mechanisms, transmission mechanisms of automobiles, and tractors, etc.; level 6 is suitable for precisions of 5-10 μm. Or precision bearing systems with higher rotation speeds, such as level 5 for the front support of ordinary lathes and level 6 for the rear support; level 4 is suitable for ultra-precision machinery with a precision of less than 5 μm or very high rotation speeds, such as precision coordinate boring machines, precision Gear systems for grinding machines, precision machinery, etc.
In addition, the bearing accuracy grades under the German DIN standard are divided into PC, P4, P5, P6, P7, etc. Among them, P6 grade precision bearings are 1.5 times that of P0 grade, and P4 is 2.5 times that of P5.