Internal clearance is the amount of space between the inner raceway, outer raceway and balls.
Radial Play: up and down movement
Axial Play: end play, right and left movement.
Bearing internal clearance in operation is an important factor that has a significant influence on other factors such as noise, vibration, heat and fatigue life. The radial play in the bearing before it is fitted can be called the initial radial play. Residual or operational radial play is what is left when the bearing has been fitted. There should be a slight residual radial play in the bearing to minimize ball skidding and reduce axial play(end play). Correct selection of the initial radial play can avoid faster bearing wear.
radial internal clearance of standard deep groove ball bearings
| nominal bearing inner diameter d(mm) | clearance | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| C2 | C0 (CN) | C3 | C4 | C5 | |||||||
| exceed | below | min. | max. | min. | max. | min. | max. | min. | max. | min. | max. |
| 10 (be limited to) | - | 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 | 25 | 20 | 36 | 25 | 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 | 60 |
| 65 | 80 | 1 | 15 | 10 | 30 | 25 | 51 | 46 | 71 | 65 | 105 |
| 80 | 100 | 1 | 18 | 12 | 36 | 30 | 58 | 53 | 84 | 75 | 120 |
radial internal clearance of miniature bearings
| clearance mark | MC1 | MC2 | MC3 | MC4 | MC5 | MC6 | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| clearance | max. | min. | max. | min. | max. | min. | max. | min. | max. | min. | max. | min. |
| 0 | 5 | 3 | 8 | 5 | 10 | 8 | 13 | 13 | 20 | 20 | 28 | |
bearing clearance selection
Maximum bearing life is with very slight preload. However, a slight increase in this theoretical preload can have a considerably detrimental effect on the bearing life. C0(CN) is usually used for standard deep groove ball bearings, and MC3 is used for miniature bearings.Radial play has nothing to do with precision grade.
| operating condition | clearance |
|---|---|
| clearance fit for inner and outer ring. low axial load no axial load carrying requirement select bearing with reduced radial clearance lower vibration and noise low speed | MC1, MC2, C2 |
| lower frictional torque standard axial load average axial load carrying requirements slight interference fit for inner ring clearance fit for outer ring average/low speed | MC3, MC4, C0(CN) |
| extremely low frictional torque high axial load high axial load carrying requirements heavy interference fit to support high loads or shock loads large temperature gradient from inner ring to outer ring high degree of shaft deflection | MC5, MC6, C3, C4,C5 |