How to understand the structural code of rolling bearings in mechanical design?

The rolling bearing code consists of basic code, pre code, and post code, represented by letters and numbers. The meaning of the code is as follows:

1. Basic code

The basic code is used to indicate the inner diameter, diameter series, width series, and type of the bearing, usually consisting of five digits. It is described as follows:

1) The inner diameter of the bearing is represented by an H-digit number starting from the right of the basic code. 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 are00, 

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 (i.e. the series of changes in outer diameter and width of bearings with the same structure and inner diameter) are 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. Thrust bearings are consistent with radial bearings, except for using 1 to represent the extra light series.

3) The width series of bearings (i.e. the series of changes in the width of bearings with the same structure, inner diameter, and diameter series) are represented by the fourth digit from the right of the basic code. When the comparison of the width series diameter series is listed as 0 series (normal 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).

2. Post code

The post code of bearings is represented by letters and numbers to indicate the structure, tolerances, and special material requirements of the bearings. There is a lot of content in post code, and below are a few commonly used codes.

1) The internal structure code refers to the different internal structures of the same type of bearing, represented by letters following the basic code. For example, angular 

contact ball bearings with contact angles of 15 °, 25 °, and 40 ° are respectively represented by C, AC, and B to indicate the different internal structures.

2) The tolerance levels of bearings are divided into 6 levels, including 2, 4, 5, 6, 6X, and 0, from high to low. The codes are/PZ,/P4 '/PS,/P6,/P6X, and/PO, respectively.

In the tolerance level, 6X level is only applicable to tapered roller bearings; Level 0 is a regular level and is not indicated in the wheel bearing code.

3) The commonly used radial clearance series of bearings are divided into 6 groups: 1 group, 2 groups, 0 groups, 3 groups, 4 groups, and 5 groups, with radial clearance 

increasing in order. O group clearance is a commonly used clearance group, which is not indicated in the bearing code. The remaining clearance groups are represented 

by/CI,/CZ,/C3,/C4, and/CS in the bearing code, respectively.

3. Pre code

The prefix of the bearing is used to represent the components of the bearing, represented by letters. If L is used to represent the separable ring of the separable bearing; K represents the rolling element and cage components of the bearing, etc.

There are many types of rolling bearings in practical applications, and the corresponding bearing codes are also quite complex. The codes introduced above are the basic 

and commonly used parts of bearing codes. Once familiar with these codes, you can identify and select commonly used bearings. For detailed coding methods for rolling 

bearings, please refer to GBT272-93. Note: The numbers one to five below the basic code indicate the ordinal position of the code from right to left.

Basically, it depends on the first digit or letter at the beginning

1. Self aligning ball bearing 2. Self aligning roller bearing or thrust self aligning roller bearing

3 tapered roller bearings and 4 double row deep groove ball bearings

5 thrust bearings 6 deep groove ball bearings

7 angular contact ball bearings 8 thrust cylindrical roller bearings

N cylindrical roller bearing U outer spherical contact ball bearing

Q Four point contact ball bearing