Standards for bearings

Taking 6317 as an example, simply put, the 6 represents the bearing type, indicating a deep groove ball bearing; the 3 is the width code; the 17 denotes the inner diameter of the bearing, and multiplying 17 by 5 gives the value of its inner diameter

The poster can search on the forum or buy a \"Hardware Manual\" to take a look; it’s very simple. The standards for bearings are complex and numerous, including both new and old standards; it’s not something that can be explained in just a few words.

Universal bearing coding method: It is divided into: prefix code, basic code, and suffix code. 　　1. Basic code (type code, size code, inner diameter code) The basic code is used to indicate the bearing’s inner diameter, diameter series, width series, and type; it generally consists of up to five digits, as explained below: 1) The bearing’s inner diameter is indicated by the first digit from the right side of the basic code. For bearings with a common inner diameter of d=20～480 mm, the inner diameter is usually a multiple of 5; these two digits represent the quotient obtained by dividing the bearing’s inner diameter by 5. For example, 04 indicates d=20 mm ； 12 indicates 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 respectively. For bearings with an inner diameter less than 10 mm and greater than 500 mm, there are separate regulations regarding the method of indicating the inner diameter; refer to GB/T272—93. 　　2) The diameter series of bearings (i.e., the range of variations in outer diameter and width for bearings with the same structure and inner diameter) is indicated by the third digit from the right in the basic code. For example, for radial bearings and radial thrust bearings, 0 and 1 indicate the extra-light series ； 2 indicates the light series ； 3 represents the medium series ； 4 denotes the heavy series. The size comparison between the various series is shown in the figure below. Except that the thrust bearings are denoted by 1 for the ultra-light series, their notation is the same as that of the radial bearings. 　　3) The width series of bearings (i.e., the series of variations in bearing width with identical structure, inner diameter, and outer diameter) is indicated by the fourth digit from the right in the basic code. When the width series in the comparison column of the diameter series in Figure 13-4 is the 0 series (normal series), the width series code O need not be indicated in the designation for most bearings; however, for self-aligning roller bearings and tapered roller bearings, the width series code 0 should be indicated. 　　The diameter series codes and width series codes are collectively referred to as dimension series codes. 　　4) The bearing type code is indicated by the fifth digit from the right of the basic code (for types such as cylindrical roller bearings and needle roller bearings, the type code is a letter). 　　2. Postcodes The postcodes of bearings use letters and numbers to indicate the bearing’s structure, tolerances, special material requirements, and so on. There are many types of post-codes, and below are a few commonly used ones. 　　1) The internal structure code indicates different internal structures of bearings of the same type, and is represented by a letter following the basic code. For example, angular contact ball bearings with contact angles of 15°, 25°, and 40° are denoted by C, AC, and B respectively to indicate the differences in their internal structure. 　　2) The tolerance grades of bearings are divided into 6 levels: 2, 4, 5, 6, 6X, and 0. These levels range from the highest to the lowest, and their codes are respectively /PZ, /P4, /PS, /P6, /P6X, and /PO. Among the tolerance grades, grade 6X is only applicable to tapered roller bearings ； Level 0 is the standard level and is not indicated in the bearing code. . 　　3) The common radial clearance series for bearings are divided into 6 groups: Group 1, Group 2, Group 0, Group 3, Group 4, and Group 5, with the radial clearance increasing in order from smallest to largest. Group o clearance is a commonly used clearance category, which is not indicated in the bearing code; the other clearance categories are denoted in the bearing code by /CI, /CZ, /C3, /C4, and /CS respectively. 　　3. Prefix code The prefix code of a bearing is used to indicate its components, and it is represented by letters. If L is used to represent the separable ring of a separable bearing ； K denotes the rolling elements of the bearing, the cage assembly, and so on.

As a supplementary note, the bearing models may not be entirely standardized within some companies, but they are roughly the same. The type of bearing for non-standard models can be deduced based on the basic code and application scenario. At first, I also got confused all the time; use it more often and refer to the \"Mechanical Design Handbook\" more often – you’ll master it quickly. :)

This is a very practical software that can determine the inner diameter, outer diameter, and thickness of bearings based on their model number, and it can also perform reverse calculations! But the bearing model should not have any prefix codes!

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