1. Rolling bearing grade classification

·GB/T307.1-94 "Radial bearing tolerance" radial bearing tolerances other than tapered roller bearings are divided into 0, 6, 5, 4 and 2 levels.

· Tapered roller bearing tolerances are divided into 0, 6X, 5 and 4 levels.

·GB/T307.4-94 "Thrust ball bearing tolerance" Thrust ball bearings are divided into 0, 6, 5, 4 levels.

·JB5286-91 "Supplementary Technical Conditions for Precision Rolling Bearings for Machine tool Spindles" specifies the SP class and UP class tolerances for precision rolling bearings for machine tool spindles - double row cylindrical roller bearings.

·JB/T6362 "SP and UP tolerance of two-way thrust angular contact ball bearings for machine tool spindle.

2. The tolerance grade of rolling bearing includes content

Rolling bearings include dimensional tolerances and form tolerances.

1. Dimensional tolerances, items related to shaft or bearing seat installation:

· Allowable deviation of inner diameter, outer diameter, ring width and assembly width.

· Allowable deviation of roller group diameter.

· The allowable limit value of the chamfer size.

2. Form and position tolerance, items related to the runout of the rotating body:

· Allowable radial runout and end runout values of finished bearings (Kia, Kea, Sia, Sea, Sd, SD).

· Thickness deviation of thrust bearing raceway (Si, Se).