Bearing code analysis

The model of a bearing usually consists of three parts: a prefix, a base code, and a suffix code. In daily use, bearings are usually identified by their basic model, which includes type code, size code, and inner diameter code. The post code, on the other hand, describes in detail the special requirements of the bearing structure, tolerances, and materials through letters and numbers. In addition, the prefix is used to indicate different components of the bearing and is labeled with letters.
Basic code
The basic code is the key part of the bearing model, which details the inner diameter, diameter series, width series, and type of bearing. This code usually contains a maximum of five digits, which can be interpreted as follows:
(1) Bearing inner diameter
The inner diameter information is included in the first digit from the right of the code. For the commonly used inner diameter range (20-480mm), these inner diameters are usually multiples of 5, and these two digits represent the quotient of the bearing inner diameter size divided by 5. For example, 04 represents an inner diameter of 20mm, while 12 represents an inner diameter of 60mm. For bearings with inner diameters of 10mm, 12mm, 15mm, and 17mm, their inner diameter codes are 0002 and 03, respectively. If the inner diameter is less than 10mm or greater than 500mm, there will be a specific representation method, which can refer to the GB/T272-93 standard.
(2) Diameter series
The variation of the diameter series is represented by the third digit from the right of the code. For radial bearings and radial thrust bearings, different numbers represent different series, such as 1 for the ultra light series, 2 for the light series, 3 for the medium series, and 4 for the heavy series. The ultra light series of thrust bearings is represented by 1, and the rest are the same as radial bearings.
(3) Width series
When the width series is 0 series (i.e. normal series), most bearings can omit the width series code O in the code. But for self-aligning roller bearings and tapered roller bearings, the width series code O should be clearly marked. The diameter series code and width series code are collectively referred to as the size series code.
(4) Bearing type
The type code is located in the fifth position from the right of the basic code and is represented by a number or letter. For example, for cylindrical roller bearings and needle roller bearings, their type codes are specific letters.
Post code
The post code is used to describe in detail the structure, tolerances, materials, and other special requirements of the bearing. These codes usually contain letters and numbers to meet specific design requirements. In some cases, the content of the post code may be quite complex, but mastering some commonly used codes will help to better understand and select bearings. For example, internal structure codes are used to distinguish different internal structures of the same type of bearing, such as the contact angle of angular contact ball bearings.
(2) Tolerance grade of bearings
The tolerance level of bearings is an important indicator for measuring their manufacturing accuracy, which is divided into 6 levels, from high to low:/ PZ,/P/PS,/P/P6X, and/PO. It should be noted that the 6X grade is only applicable to tapered roller bearings, while the 0 grade is a regular grade and is usually not indicated in the wheel bearing code.
(3) Radial clearance of bearings
Radial clearance refers to the radial clearance of a bearing