Release time : 2015-06-11 07:44:56
By Bearing Manufacturer>Bearing News>How to identify the ball bearing size and grade?
Usually we use the final two digit of bearing model x 5, it can calculate the ball bearing size. Example: The inner diameter of 6204 is 04x 5 = 20 mm.Ball bearing size's identification method in special situations.
When inner diameter less than 20 mm: 10, 12, 15, 17, corresponding code for 00, 01,02, 03.
When inner diameter less than 10 mm, last digit of bearing model is the bearing's inner diameter size; Example: bearing 608 zz, last digit is 8, then its inner diameter is 8 mm.
When inner diameter is not a multiple of 5 or more than equal to 500 mm, inner diameter code with forward slash '/' off. Another kind of circumstance: The old model of Needle Roller Bearings with '/' off.
This several circumstances' / 'behind several numerical for bearing inside diameter size. See below says an example:
Bearing type 619/1.5, 62/22, 60/500, 3519/1120, 7943/25.Inner diameter size (mm) 1.5, 22, 500, 1120, 25.
The above are several identification method of ball bearing size, many companies models are not all the same, In actual situation shall prevail. Specific reference to all kinds of material and each manufacturer sample.
Below is tolerance grade said methods:
Radial Ball Miniature Bearings and angular contact ball bearing five levels, from high to low: P2, P4, P5, P0.The old level representation method: B, C, D, E, G
Tapered roller bearing points level 4, from high to low: P4, P5, P6x, P0.The old level representation method: C, D, Ex, G (E).
Thrust ball bearing points level 4, from high to low: P4 P0 P5 moves.The old level representation method: C D E G
If need higher tolerance levels of bearing, can according to GB307 standard choose suitable tolerance grade bearing.
Clearance code: clearance code points in six/C1 / C2 / C3 / C4 / CM for code, CM for dynamo bearing clearance group, other clearance group the greater the numerical clearance; Based on C0 group
clearance not marked. Choose bearing clearance should fully consider bearing mounting hole and bearing and shaft fit tolerance and temperature, details please refer to the GB/T4604 standard or consulting site.
Code method examples:
Example (1) 6308 6 -- Deep Groove Ball Bearings , 3 - series, 08 - bore d = 40 mm, tolerance grade "O" level, clearance group is "0" group are not labeling.
Example (2) N105 / P5 N - cylindrical roller bearing, 1 -- extra light series, 05 - bore d = 20 mm, tolerance level for 5 level, clearance group is "0" group not labeling.
Example (3)7214 C/P4 7 - angular contact ball bearings, 2 -- light series, 14 - bore d = 70 mm, C - nominal contact Angle a = 15, P4 - tolerance grade 4 level, clearance group is "0" group;
Example (4) 30213 3 -- tapered roller bearing, 0 - normal width (0 not omitted), 2 -- light series, 13 - bore d = 65 mm, tolerance grade 0 level, clearance group is "0" group;