The general bearing code is 5-digit: X X X XX
1. The last two digits represent the inner diameter,For bearings with a commonly used inner diameter of d=20-480mm, the inner diameter is generally a multiple of 5. These
two digits represent the quotient obtained by dividing the inner diameter size of the bearing by 5. For example, 04 represents d=20mm; 12 represents d=60mm, etc. For
bearings with inner diameters of 10mm, 12mm, 15mm, and 17mm, the inner diameter codes are 00, 01, 02, and 03 in sequence. For bearings with inner diameters less than
10mm and greater than 500mm, there are other regulations on the method of inner diameter representation, which can be found in GB/T272-93.
2. The diameter series of bearings is represented by the third digit from the right of the basic code.For example, for radial bearings and radial thrust bearings, 0 and 1
represent the extra light series; 2 represents the light series; 3 represents the middle series; 4 represents a heavy series. The size comparison between each series is shown
in the following figure. Thrust bearings are consistent with radial bearings, except for using 1 to represent the extra light series.
3. The width series of bearings is represented by the fourth digit from the right of the basic code.When the comparison of the width diameter series is listed as the 0 series,
the width series code O may not be indicated in the code for most bearings, but for self-aligning roller bearings and tapered roller bearings, the width series code 0 should
be indicated. The diameter series code and width series code are collectively referred to as the size series code.
4. The bearing type code is represented by the fifth digit from the right of the basic code (using letters for type codes such as cylindrical roller bearings and needle roller
bearings).