The accuracy of rolling bearings is divided into (main) dimensional accuracy and rotational accuracy. The accuracy grades have been standardized and are divided into six grades: 0 grade, 6X grade, 6 grade, 5 grade, 4 grade and 2 grade.

    Accuracy increases sequentially from grade 0, and grade 0 is sufficient for general purposes, but when used in the conditions or occasions shown in Table 1, an accuracy of grade 5 or higher is required.

    Although the above precision grades are formulated based on ISO standards, their names are different in national standards.

Dimensional accuracy (items related to shaft and housing installation)

1. Allowable deviation of inner diameter, outer diameter, width and assembly width

2. Allowable deviation of inner compound circle diameter and outer compound circle diameter of roller group

3. Allowable limit value of chamfer size

4. Allowable variation of width

Rotation accuracy (items related to the beating of rotating body)

1. Allowable radial runout and axial runout of inner and outer rings

2. The allowable lateral runout of the inner ring

3. The allowable variation of the inclination of the outer diameter surface

4. Allowable variation of thrust bearing raceway thickness

5. The allowable deviation and allowable variation of the tapered hole

Bearing type and applicable precision class

Bearing type Applicable standard Applicable precision class

Deep groove ball bearing GB307 Grade 0 Grade 6 Grade 5 Grade 4 Grade 2

Angular contact ball bearings Class 0 Class 6 Class 5 Class 4 Class 2

Self-aligning ball bearing Class 0

Cylindrical roller bearings Class 0 Class 6 Class 5 Class 4 Class 2

Tapered roller bearings Metric series (single row) GB307 Grade 0 Grade 6 Grade 6 Grade 5 Grade 4

Metric series (double row, four row) SB/T5341994 Grade 0

Inch series SB/CO/T1089 Class4 Class2 Class3 Class0 Class00

Spherical roller bearing GB307 grade 0

Thrust ball bearings Class 0 Class 6 Class 5 Class 4

Thrust spherical roller bearings Class 0

The GB/T30794 standard divides the bearing grades into G E D C B. ISO, JIS and other standards are compared as follows:

Standard Accuracy

GB/T30794 B C D E G

ISO CLASS2 CALSS4 CLASS5 CLASS6 NORMAL CLASS

DIN P2 P4 P5 P6 P0

ANSI ABEC9 ABEC7 ABEC5 ABEC3 ABEC1

JIS JIS2 JIS4 JIS5 JIS6 JIS0

Selection of precision

Performance Requirement Use Case Applicable Accuracy Class

It is required to place the object with high runout accuracy. Audio and video machine spindles (video recorders, tape recorders)

Radar, parabolic antenna shaft

Machine tool spindle

Electronic computer, disk spindle

Aluminum foil roll neck

Multi-stage rolling mill support bearings

P4

P5, P4, P2, ABEC9

P5, P4, P2, ABEC9

P5

P4

High-speed rotation supercharger

Jet engine main shaft, auxiliary machine

centrifuge

LNG pump

Turbomolecular pump spindle, protected bearings

Machine tool spindle

Tensioners P5, P4

P5, P4

P5, P4

P5

P5, P4

P5, P4, P2, ABEC9

P5, P4

Small friction and friction change are required to control machines (synchronous motors, servo motors, gyro gimbals)

Meter

Machine Spindle P4, ABMA 7P

P5

P5, P4, P2, ABEC9

General accuracy Small motors, gear transmissions, cam transmissions, generators, low-inductance synchronous servo motors, pressure rotors, printers, copiers, testing instruments P0, P6