The bearing model generally has a pre-code, a basic code and a post-code. In general, the bearing model is only indicated by the basic model. The basic model generally consists of three parts, type code, size code and inner diameter code. The post code is to use letters and numbers to indicate the structure, tolerance and special requirements of materials of the bearing. The prefix code is used to indicate the sub-components of the bearing, which are represented by letters.
The tolerance grades of bearings are divided into 2 grades, 4 grades, 5 grades, 6 grades, 6X grades and 0 grades, a total of 6 grades, from high to low, and their codes are /PZ, /P4, /PS, /P6 , /P6X and /PO. Among the tolerance grades, grade 6X is only applicable to tapered roller bearings; grade 0 is ordinary grade, which is not marked in the wheel bearing code.
The commonly used radial clearance series of bearings are divided into 1 group, 2 groups, 0 groups, 3 groups, 4 groups and 5 groups, a total of 6 groups, and the radial clearances are in order from small to large. The o group clearance is a commonly used clearance group, which is not marked in the bearing code, and the rest of the clearance groups are represented by /CI, /CZ, /C3, /C4, /CS in the bearing code.