From a bearing model we can read the sizes of a bearing we are looking for.
Bearings generally have three dimensions, i.e. inner diameter dimension, outer diameter dimension and width dimension, which are reflected in the bearing model.
Take 21307CDE4 as an example
CDE4：is a postcode
21307：is the basic code of bearing. Means the size of the bearing.
07：ID code. Indicates the inner diameter of the bearing=07×5=35mm
3： Outside diameter code, indicates that the outer diameter of the bearing is "3" series. For detailed dimension parameters, please refer to the manual.
1： Width code. Indicates that the width of the bearing is "1" series. For detailed parameters, please refer to the manual.
2： Type structure code. Indicates that this bearing is a double row self-aligning roller bearing.
Correlation between inner diameter and model:
1.For bearings with inner diameter less than 10 mm, the inner diameter of the bearing is the inner diameter code of the bearing.
Example: the inner diameter of 608T1XZZMC3ER bearing = 8mm.
2. Bearings with an inside diameter of 10 mm or more and 17 mm or less:
Inner diameter = 10 mm, code of bearing inner diameter: 00
Example: inner diameter of 6200CM bearing = 10 mm
Inner diameter = 12mm, code of bearing inner diameter: 01
Example: the bearing inner diameter of 6901-2Z = 12mm.
Inner diameter = 15mm, code of bearing inner diameter: 02
Example: the bearing inner diameter of 6902-2Z = 15mm.
Inner diameter = 17mm, code of bearing inner diameter: 03
Example: the bearing inner diameter of 6903-2Z = 17mm.
3. Bearings with an inside diameter of 20 mm or more and 180 mm or less
ID dimension = ID code of bearing × 5
Inner diameter of 23084CAME4C3S11 bearing = 84 × 5 = 420mm
4. There is a slash (/) in the bearing model. The number on the right side of the slash is the inside diameter of the bearing.
If the association rules of bearing inner diameter and model do not conform to the above three rules, all the slashes are used.
5. The inside diameter of the bearing is 1. 5mm, not in accordance with normal rules
Example: The inner diameter of 63 / 32CM bearing is 32mm, which is not in accordance with the normal rules.
Example: The inner diameter of 230 / 530CA bearing is 530mm, which is not in accordance with the rules.
Bearing models with slash are generally found in bearings with inner diameter larger than 480mm; in pressed outer ring and solid ferrule needle bearing; in various non-standard bearings; in European code small diameter ball bearing (inner diameter smaller than 10 mm), etc.