Numbers in bearing codes can all represent different meanings. Understanding these numbers makes it easy to grasp technical information of each bearing code, including: Size, load capacity, gap, etc.
1. Dimension of bearings
The last two digits are in the bearing code 00-99 to indicate the inner diameter of the bearing. The inner diameter of the bearing will be equal to the value of these 2 digits multiplied by 5 and give a result in mm except:
Code with tail 00: inner diameter of bearing is 10mm.
Code with tail 01: inner diameter of bearing is 12mm.
Code with tail 02: inner diameter of bearing is 15mm.
Code with tail 03: inner diameter of bearing is 17mm.
For example the bearing code: 6230, we take 30 times 5 to get 150mm. This is the value of the inner diameter of this bearing.
2. Capacity of bearings
Bearing capacity is shown in the number 3 from right to left on the bearing code.
|
1 or 7 |
Very light load |
|
2 |
Light load only |
|
3 |
Average load only |
|
4 |
Heavy load only |
|
5 |
Only very heavy load |
|
6 |
Only average load like number 3 but thicker |
|
8-9 |
Only very, very light load |
3. Meaning of bearings' classification
The fourth digit from right to left indicates the bearing from 0-9
|
0 |
1 layer ball |
|
1 |
Double-layer ball |
|
2 |
1 layer short roller ball |
|
3 |
Two-layer short roller ball |
|
4 |
1 layer long roller ball |
|
5 |
Twisted roller ball |
|
6 |
Block roller round ball |
|
7 |
Tape roller ball |
|
8 |
Not radial block ball |
|
9 |
Block roller ball |
4. The meaning of bearings' structure
The 5th digit from right to left represents its structure:
|
3 |
Cylindrical roller ball 1 row short, inner ring with no barrier |
|
4 |
Same as 3, but with a barrier |
|
5 |
There is 1 slot for mounting the positioning brake on the outer barrier |
|
6 |
There is a thin ring to block oil in steel |
|
8 |
There are two thin rings that block the oil in steel |
|
9 |
Short cylindrical roller ball 1 row, in the inner ring has a rim that blocks the roller |
555. Standard for clearance of bearings
|
Axle size |
New ball |
New roller ball |
Old ball alow |
|
20-30 |
0.01-0.02 |
0.03-0.05 |
0.1 |
|
30-50 |
0.01-0.02 |
0.05-0.07 |
0.2 |
|
55-80 |
0.01-0.02 |
0.06-0.08 |
0.2 |
|
85-120 |
0.02-0.03 |
0.08-0.1 |
0.3 |
|
130-150 |
0.02-0.03 |
0.10-0.12 |
0.3 |
6. Standard for clearance of bearings
|
Diameter of the shaft |
Clearance between shaft and silver ring |
|||
|
<1000 v/p |
>1000 v/p |
|||
|
Standard |
Allow |
Standard |
Alow |
|
|
18-30 |
0.040-0.093 |
0.1 |
0.06-0.118 |
0.12 |
|
30-50 |
0.05-0.112 |
0.12 |
0.075-0.142 |
0.15 |
|
50-80 |
0.065-0.135 |
0.14 |
0.095-0.175 |
0.18 |
|
80-120 |
0.08-0.16 |
0.16 |
0.12-0.210 |
0.22 |
|
120-180 |
0.100-0.195 |
0.20 |
0.150-0.250 |
0.30 |
|
180-260 |
0.120-0.225 |
0.24 |
0.180-0.295 |
0.40 |
|
260-360 |
0.140-0.250 |
0.26 |
0.210-0.340 |
0.5 |
|
360-500 |
0.170-0.305 |
0.32 |
0.250-0.400 |
0.6 |
