Talking about the coding rules of imported bearings

The code of the imported bearing is divided into the pre-code, the basic code and the post-code. Any code must be coded in strict accordance with the coding rules. The coding rules for imported bearings are described in detail below.
1. Front code The front code of the bearing is used to indicate the sub-parts of the bearing, which are indicated by letters. For example, L denotes a separable ferrule of a separable bearing; K denotes a rolling element and a cage assembly of the bearing, and the like.
    There are many types of rolling bearings for practical applications, and the corresponding bearing codes are also complicated. The code number introduced above is the most basic and most commonly used part of the bearing code. If you are familiar with this part code, you can identify and select the commonly used bearings.
   
   2. Basic code (type code, size series code, inner diameter code) The basic code is used to indicate the inner diameter, diameter series, width series and type of the bearing, generally up to five digits, first described as follows:
    1) The inner diameter of the bearing is indicated by the first and right H-digit numbers from the right of the basic code. For a common inner diameter d = 20 ~ 480mm bearing inner diameter is generally a multiple of 5, these two digits represent the quotient of the bearing inner diameter size divided by 5, such as 04 for d = 20mm; 12 for d = 60mm and so on. For bearings with inner diameters of 10 mm, 12 mm, 15 mm, and 17 mm, the inner diameter codes are 00, 01, 02, and 03 in order. For bearings with an inner diameter of less than 10 mm and greater than 500 mm, the inner diameter representation method is otherwise specified, see GB/T272-93.
    2) The diameter series of the bearing (that is, the series of changes in outer diameter and width of bearings with the same structure and the same inner diameter) is represented by the third digit from the right of the basic code. For example, for a radial bearing and a radial thrust bearing, 0, 1 denotes an extra light series; 2 denotes a light series; 3 denotes a middle series; 4 denotes a heavy series. The size comparison between the series is shown in the figure below. The thrust bearing is identical to the centripetal bearing except that the 1 indicates the extra-light series.
    3) The width series of the bearing (that is, the series of changes in the bearing width of the same structure, inner diameter and diameter series) is represented by the fourth digit from the right of the basic code. When the comparison of the width series of the 13-4 diameter series is 0 series (normal series), the width series code O may not be marked for most bearings in the code number, but for the spherical roller bearing and the tapered roller bearing, the width series Code 0 should be marked. Diameter series code and width series code are collectively referred to as size series code.
    4) The bearing type code is represented by the fifth digit from the right of the basic code (for the type of cylindrical roller bearing and needle bearing, the letter is the letter).
 
   3. Post code The rear code of the bearing is a letter, number, etc., indicating the structure, tolerances and special requirements of the bearing. There are many contents of the post code. Here are a few common codes.
    1) The internal structure code indicates the different internal structure of the same type of bearing, 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 difference in internal structure.
    2) The tolerance class of the bearing is divided into 2, 4, 5, 6, 6X and 0, a total of 6 levels, from high to low, the codes are /PZ, /P4, /PS, /P6, /P6X and /PO. In the tolerance class, the 6X grade is only applicable to tapered roller bearings; the 0 grade is normal grade, and is not marked in the bearing code.
    3) The commonly used radial clearance series of bearings is divided into 1 group, 2 groups, 0 groups, 3 groups, 4 groups and 5 groups, with 6 groups in total, and the radial clearance is from small to large. o Group clearance is a commonly used clearance group, which is not marked in the bearing code. The remaining clearance groups are represented by /CI, /CZ, /C3, /C4, /CS in the bearing code.