1.Basic code
The basic code of the rolling bearing is used to indicate the inner diameter, diameter series, width series and type of the bearing, generally up to five digits, as follows:
1) The inner diameter of the bearing is indicated by the first and second digits from the right of the basic code. For bearings with a commonly used inner diameter d=20～480mm, the inner diameter is generally a multiple of 5. These two digits represent the quotient of the bearing inner diameter size divided by 5. For example, 04 means d=20mm; 12 means 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 sequence. For bearings with an inner diameter less than 10mm and greater than 500mm, the inner diameter expression method is otherwise specified, please refer to GB/T272-93.
2) The diameter series of the bearing (that is, the series of changes in the outer diameter and width of the bearing 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 radial bearings and radial thrust bearings, 0 and 1 represent extra light series; 2 represent light series; 3 represent medium series; 4 represent heavy series. The size comparison between the series is shown in the figure below. Thrust bearings are the same as those of radial bearings except that 1 is used to indicate extra light series.
3) The width series of the bearing (that is, the series of changes in the width of the bearing with 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 diameter series in Figure 13-4 is listed as 0 series (normal series), for most bearings, the width series code O may not be marked in the code, but for spherical roller bearings and tapered roller bearings, the width series Code 0 should be marked.
The diameter series code and the 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 (letters for cylindrical roller bearings and needle roller bearings).
2.Postcode
The rear code of the bearing uses letters and numbers to indicate the structure, tolerances and special requirements of materials, etc. of the bearing. There are many post code names. Here are a few commonly used codes.
1) The internal structure code refers to the different internal structure of the same type of bearing, which is indicated by a 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) Bearing tolerance levels are divided into 2 levels, 4 levels, 5 levels, 6 levels, 6X levels and 0 levels, a total of 6 levels, from high to low, the codes are /P2, /P4, /P5, /P6, /P6X and /P0. Among the tolerance grades, 6X grade is only applicable to tapered roller bearings; 0 grade is ordinary grade, which is not marked in the wheel bearing code. .
3) The commonly used bearing radial clearance series are divided into 1, 2, 0, 3, 4, and 5 groups, a total of 6 groups, 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, and /CS in the bearing code.
3.Pre-code
The front code of the bearing is used to indicate the sub-components of the bearing, which is indicated by letters. For example, L represents the separable ring of the separable bearing; K represents the rolling element and cage assembly of the bearing and so on.
There are many types of rolling bearings in practical applications, and the corresponding bearing codes are also more complicated. The codes introduced above are the most basic and commonly used parts of bearing codes. If you are familiar with this part of codes, you can identify and search for commonly used bearings. For the detailed code method of rolling bearings, please refer to GBT272-93.
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