Time：2019.12.27 Source：Roller Bearings Suppliers

Rolling bearings codes refers to the inner diameter, diameter series, width series, and type of the bearings, which are generally up to five digits. The code is composed of basic code, post code, and front code.

**Basic code**

First, as follows:

1) The inner diameter of the bearings is indicated by the first and second digits of the rolling bearings code. For bearings with a common inner diameter d = 20 ~ 480mm, the inner diameter of the bearings is usually a multiple of 5. These two digits represent the quotient of the inner diameter of the bearings divided by 5, such as 04 for d = 20mm; 12 for d = 60mm and so on. For bearings with inner diameters of 10mm, 12mm, 15mm and 17mm, the inner diameter codes are 00, 01, 02 and 03 in order. For bearings with an inner diameter of less than 10mm and more than 500mm, the method of expressing the inner diameter is otherwise specified, see GB / T272-93.

2) The diameter series of bearings (that is, the series of changes in outer diameter and width of bearings with the same structure and the same inner diameter) is indicated by the third digit from the right of the basic code. For example, for radial bearings and radial thrust bearings, 0 and 1 represent extra light series; 2 represents light series; 3 represents medium series; 4 represents heavy series; 7 represents ultra extra light;

Thrust bearings size and diameter series are slightly different from radial bearings. Among them, 0means super light series, 1 means extra light series, 2 means light series, 3 means medium series, 4 means heavy set, and 5 means extra heavy series.

3) The width series of the bearings (namely, the series of changes in bearings width in which the structure, inner diameter and diameter series are the same) is indicated by the fourth digit from the right of the basic code. When the width series of the diameter series shown in Figure 13-4 is the 0 series (normal series), the width series code O is not marked in the code for most bearings, but for spherical roller bearings and tapered roller bearings, the width series Code 0 shall be marked. The diameter series and width series are collectively referred to as the size series.

4) The rolling bearings codes is indicated by the first digit from the left of the basic code.

5)Rolling bearings codes:

0 means double row angular contact ball bearings

1 means self-aligning ball bearings

2 indicates spherical roller bearings and thrust spherical roller bearings

3 indicates tapered roller bearings

4 means double row deep groove ball bearings

5 means thrust ball bearings

6 means deep groove ball bearings

7 means angular contact bearings

8 means thrust cylindrical roller bearings

N means cylindrical roller bearings and double row cylindrical roller bearings NN

U means outer spherical bearings

QJ means four-point contact ball bearings

**Post code**

Rolling bearings codes in the behind is composed by letters and numbers to indicate the bearings structure, tolerances and special requirements of materials and so on. There are a lot of postcodes. Here are some commonly used codes.

1) The internal structure code indicates different internal structures of the same type of bearings, which is indicated by the letter followed by the basic code. For example, angular contact ball bearings with contact angles of 15 °, 25 °, and 40 ° use C, AC, and B to indicate the differences in the {HotTag} internal structure.

2) bearings tolerance grades are divided into 2 grades, 4 grades, 5 grades, 6 grades, 6X grades, and 0 grades. There are a total of 6 grades, in order from high to low, and their codes are / PZ, / P4, / PS, / P6, / P6X, and / P0. Among tolerance grades, grade 6X is only applicable to tapered roller bearings; grade 0 is ordinary grade and is not marked in the bearings code.

3) The commonly used bearings radial clearance series are divided into 1 group, 2 groups, 0 groups, 3 groups, 4 groups and 5 groups, a total of 6 groups, the radial clearance in order from small to large. The clearance of group o is a common clearance group, which is not marked in the bearings code. The remaining clearance groups are represented by / C1, / C2, / C3, / C4, / C5 in the bearings code.

**Front code**

Rolling bearings codes in the front is used to indicate the sub-components of the bearings, which are represented by letters. For example, L is the separable ferrule of the separable bearings; K is the rolling element and cage assembly of the bearings.

There are many types of rolling bearings used in practice, and the corresponding bearings codes are also more complicated. The code introduced above is the most basic and commonly used part of the bearings code. Once you are familiar with this code, you can identify and check the commonly used bearings.

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