How To Read And Identify Bearing Numbers

Bearing numbers are a critical part of any bearing identification process. They provide essential information about the bearing’s size, type, and manufacturer. By understanding how to read and identify bearing numbers, you can ensure that you are getting the right bearing for your application.

The Basics Of Bearing Numbers

Bearing numbers usually consist of three distinct parts: prefix, base name and suffix. The first few digits of the number usually indicate the size of the bearing. The following number may indicate the bearing type, material or manufacturer.

Here is a breakdown of the most common components of a bearing number:

  • Bore diameter (d):
    The bore diameter indicates the inner diameter of the bearing and is critical to the fit of the bearing to the shaft. It usually occupies the third and fourth positions in the bearing number.
  • bearing series:
    The series indicates the width or thickness of the bearing and helps determine its load carrying capacity. This information usually follows the bore diameter.
  • Bearing width (B):
    The letter “B” indicates the width of the bearing, i.e. the distance between the outer and inner rings. This is important to ensure that the bearing is compatible with its housing.
  • Radial clearance and internal clearance:
    Additional characters may indicate the radial clearance or internal clearance of the bearing. Typically, “C” denotes standard clearance and variants such as “C2” and “C3” denote increased clearance.
  • Suffixes:
    Various suffixes may be used to designate specific features such as seals, covers, special materials, or manufacturing specifications.

Examples Of Bearing Numbers

Here the 6205-2RS1 CHINA bearing numbers and what they mean:

  • Bearing type code: 6205 indicates the size code of the bearing, specifically 25 mm inner diameter, 52 mm outer diameter, 15 mm width
  • Front code: 2RS indicates that the bearing has two sealing rings to improve its durability and performance
  • Rear code: 1 CHINA indicates additional features and characteristics of the bearing, such as material, lubrication method, and so on. In this example, 1 indicates that the bearing is made of phosphor steel, and CHINA indicates that the bearing is produced in China.

The following is an example of 32005 bearing numbers:

The third and fourth digits in the bearing number are important because they usually represent the bearing’s inside diameter (ID) in millimetres.
Please refer to the table below:

code inner diameter
00
10 mm
01
12 mm
02
15 mm
03
17 mm
04
20 mm
05
25 mm
06
30 mm
greater than
Multiplication of the above => 500mm

Additional Information On Bearing Numbers

In addition to the basic components discussed above, bearing numbers can also include a variety of other information, such as:

Suffixes: Suffixes are used to further specify the bearing’s characteristics. Some common suffixes include:

  • -2RS: This suffix indicates that the bearing has two rubber seals.
  • ZZ: This marking indicates that the bearing is shielded on both sides.
  • Z: This marking indicates that the bearing is shielded on one side.
  • -C3: This suffix indicates that the bearing has a C3 clearance.
  • -M: This suffix indicates that the bearing is made of magnetic material.

Specialty markings: Some bearings may have specialty markings that indicate special features or characteristics.
FAG: This marking indicates that the bearing is made by the FAG company.

The Importance Of Bearing Numbers

The bearing number is an important identifier that provides critical technical information about the bearing. Understanding the importance of the bearing number is critical to the proper selection, installation and maintenance of bearings.

        >>  Type identification:The first part of the bearing number usually indicates the type of bearing. This is important for the user to quickly understand the basic design of the bearing and the application scenario.

        >>  Size and fit:The third and fourth digits in the bearing number usually represent the bore diameter of the bearing. This information is critical to ensure that the bearing is properly seated on the shaft and has a good fit with the housing. Correct size and fit are key factors in the proper functioning of the bearing and in avoiding excessive wear.

        >>  load carrying capacity:Information on bearing series and widths provides clues as to the bearing’s load carrying capacity. Bearings of different series and widths may be suitable for different load conditions. By knowing the load carrying capacity of the bearings, users can select the right bearings for their applications and ensure stable equipment operation.

        >>  internal clearance and clearance:The bearing number may contain information about the internal clearance or play of the bearing. This is critical to accommodate thermal expansion, vibration and changes in operating conditions. Different internal clearances can affect the kinematic characteristics and operating performance of the bearing.

        >>  Application-specific characteristics:The suffix to the bearing number usually provides information about the bearing’s special features or application, such as seals, dust shields, high temperature characteristics, etc. This helps the user to select a bearing for a particular environment or operating condition.

        >>  Maintenance and replacement:Knowing the bearing number means that users can accurately match and replace existing bearings during maintenance and replacement. This helps to improve equipment reliability and reduce downtime.

Conclusion

Bearing numbers are a critical part of any bearing identification process.
By following these tips, you can easily read and identify bearing numbers. This will help you to get the right bearing for your application and improve the performance and reliability of your equipment.
If you are still unsure about the bearing’s identification, consult with a bearing expert. They can help you to identify the bearing and ensure that you are getting the right one for your application.

References

  • 1.For more information on “bearing numbers” please refer to JTEKT Company

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