What is the clearance of a ball bearing? Let's take the 608 bearing as an example to explain in detail.
The so-called clearance of a ball bearing refers to the internal gap within the bearing, which is often divided into two types: radial clearance and axial clearance.
This blog post will first explain radial clearance. As for axial clearance, it is related to radial clearance. In a certain sense, once the radial clearance of a bearing is determined, its axial clearance is also determined.
Let’s take the 608 ball bearing as an example . The diagram below shows the raw profile of the 608 bearing after turning. The external dimensions and the raceway need to undergo grinding.
The outer ring raceway dimension of the 608 bearing is 18.82mm. We need to grind the raceway to approximately 18.969mm.
The inner ring raceway dimension of the 608 bearing is 11.18mm. We need to grind the raceway to approximately 11.031mm.
The size of the steel balls we need to assemble is 3.969mm.
The size of the steel balls, 3.969mm, can vary, ranging from 3.949mm to 3.989mm.
If you need the radial clearance of the 608 bearing to be 10μm ：
18.969mm-11.031mm-2*3.964=10um,
Exactly! When assembling bearings, you can:
Select different steel ball sizes: By slightly adjusting the size of the steel balls (e.g., within the range of 3.949mm to 3.989mm), you can influence the radial clearance of the bearing.
Choose different inner and outer ring dimensions: Grinding or selecting inner and outer raceways of different sizes can also help fine-tune the radial clearance to meet specific requirements.
Here is the cleaned-up and organized version of the data you provided:
| Nominal Bore Diameter (d) (mm) | (C2) | (CN) | (C3) | (C4) | (C5) |
|---|---|---|---|---|---|
| 2.5 - 6 | 0 - 7 | 2 - 13 | 8 - 23 | — | — |
| 6 - 10 | 0 - 7 | 2 - 13 | 8 - 23 | 14 - 29 | 20 - 37 |
| 10 - 18 | 0 - 9 | 3 - 18 | 11 - 25 | 18 - 33 | 25 - 45 |
| 18 - 24 | 0 - 10 | 5 - 20 | 13 - 28 | 20 - 36 | 28 - 48 |
| 24 - 30 | 1 - 11 | 5 - 20 | 13 - 28 | 23 - 41 | 30 - 53 |
| 30 - 40 | 1 - 11 | 6 - 20 | 15 - 33 | 28 - 46 | 40 - 64 |
| 40 - 50 | 1 - 11 | 6 - 23 | 18 - 36 | 30 - 51 | 45 - 73 |
| 50 - 65 | 1 - 15 | 8 - 28 | 23 - 43 | 38 - 61 | 55 - 90 |
| 65 - 80 | 1 - 15 | 10 - 30 | 25 - 51 | 46 - 71 | 65 - 105 |
the 608 bearing inner diameter is 8mm:
608 Bearing Radial Clearance Values :
C2:0-7um CN/C0: 2-13um C3: 8-23um C4:14-29um C5: 20-37 um
So, the radial clearance of a bearing is determined by the bearing manufacturer based on working conditions.
If you have any questions, please contact CXE.