The grade of bearing is divided into five grades: PO-P6-P5-P4-P2, PO grade is the standard stipulated by the state, and it is also the most common standard in the bearing industry, so it is also called ordinary grade. All products are made of PO grade, and P2 grade is the highest precision grade! There are also standard technical parameters. A brief summary is as follows: Benchmarks of Accuracy
The accuracy of rolling bearings is divided into (mainly) dimensional accuracy and rotational accuracy. The accuracy level has been standardized and divided into six levels: 0, 6X, 6, 5, 4, and 2.
The accuracy increases sequentially from grade 0. For general use, grade 0 is sufficient, but when used in the conditions or occasions shown in Table 1, grade 5 or higher is required.
The above-mentioned accuracy grades are based on ISO standards, but their names differ from country to country.
Dimensional Accuracy (Items Related to Shaft and Housing Mounting)
1. Allowable deviation of inner diameter, outer diameter, width and assembly width
2. The allowable deviation of the inner and outer circle diameters of the roller group
3. The allowable limit value of the chamfer size
4. Allowable variation of width
Rotation accuracy (item related to the runout of the rotating body)
1. Allowable radial runout and axial runout of inner ring and outer ring
2. Allowable lateral runout of the inner ring
3. The allowable variation of the inclination of the outer diameter surface
4. The allowable variation of the thickness of the thrust bearing raceway
5. Allowable deviation and allowable variation of tapered holes
Bearing Type and Applicable Accuracy Class
Bearing form Applicable standard Applicable accuracy class
Deep groove ball bearings GB307 Grade 0 Grade 6 Grade 5 Grade 4 Grade 2
Angular contact ball bearings Grade 0 Grade 6 Grade 5 Grade 4 Grade 2
Self-aligning ball bearing class 0
Cylindrical roller bearings Grade 0 Grade 6 Grade 5 Grade 4 Grade 2
Tapered Roller Bearings Metric Series (Single Row) GB307 Class 0 Class 6 Class 6 Class 5 Class 4
Metric series (two-row, four-row) SB/T5341994 Class 0
Inch series SB/CO/T1089 Class4 Class2 Class3 Class0 Class00
Spherical Roller Bearing GB307 Grade 0
Thrust ball bearing Class 0 Class 6 Class 5 Class 4
Thrust spherical roller bearing 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
The placement body is required to have high beating 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 and auxiliary
Centrifuge
LNG pump
Turbomolecular pump main shaft, protection bearing
Machine tool spindle
Tensioner P5, P4
P5, P4
P5, P4
P5
P5, P4
P5, P4, P2, ABEC9
P5, P4
Requires small friction and friction variation Control machines (synchronous motors, servo motors, gyro gimbal)
Meters
Machine tool spindle P4, ABMA 7P
P5
P5, P4, P2, ABEC9
General accuracy Small motors, gear drives, cam drives, generators, low-inductance synchronous servo motors, pressure rotors, printers, copiers, testing instruments P0, P6
