How to select the precision grade of rolling bearings

The accuracy grades of rolling bearings can be divided into two types, one is dimensional accuracy and the other is rotation accuracy.

The accuracy grade standards of bearings are mainly divided into six levels: Level 0, Level 6X, Level 6, Level 5, Level 4, and Level 2. Bearing grade standards start from grade 0 and increase in sequence. For processing general workpieces, grade 0 can meet the requirements. However, in some occasions or processing requirements, bearings with grade 5 or higher precision are required.

These accuracy levels are formulated in accordance with ISO standards, but due to the influence of individual national standards, their names will vary greatly.

Dimensional accuracy of bearings

This mainly refers to items related to the installation of shafts and housings.

1. There will be deviations in the inner diameter, outer diameter, width and assembly width.

2. Deviations in the inner and outer complex diameters of the roller group are also allowed.

3. Allowable limit value of chamfer size.

4. The width is also allowed to vary.

Bearing rotation accuracy

This is an item related to the beating of the rotating body.

1. The inner and outer rings can allow axial runout and radial runout.

2. Lateral jumps may occur in the inner ring

3. There is an allowable variation in the inclination of the outer diameter surface.

4. Allowable variation in thrust bearing raceway thickness

5. Allowable deviation and allowable variation of tapered holes

Selection of bearing accuracy

1. The placement body is required to have high beating accuracy

Mainly used for audio, impact equipment and their spindles; radar, parabolic antenna shafts; machine tool spindles; electronic computers, disk spindles; aluminum foil roll necks; multi-stage rolling mill support bearings.

Applicable accuracy levels are: P4, P5, P2, ABEC9.

2. High-speed rotation

Mainly used in superchargers; jet engine spindles and auxiliary engines; centrifuges; liquefied natural gas pumps; turbomolecular pump spindles and protective bearings; machine tool spindles; and tensioners.

Applicable accuracy levels are: P4, P5, P2, ABEC9.

3. Require small friction and friction changes

Mainly used to control machines (synchronous motors, servo motors, gyro gimbals; measuring instruments; machine tool spindles.

Applicable accuracy levels are: P4, P5, P2, ABEC9, ABMA7P.

4. General accuracy

It can be mainly used in small motors, gear transmissions, cam transmissions, generators, low-induction synchronous servo motors, pressure rotors, printers, copiers, and testing instruments.

Applicable accuracy levels are: P0, P6