Bearing factors and recommended ndm limits
| Bearing type1) | Bearing
factor |
Recommended ndm limits for
load ratio |
||
| bf | C/P ≥ 15 | C/P ≈ 8 | C/P ≈ 4 | |
| – | – | mm/min | ||
| Deep groove ball bearings | 1 | 500 000 | 400 000 | 300 000 |
| Angular contact ball bearings | 1 | 500 000 | 400 000 | 300 000 |
| Self-aligning ball bearings | 1 | 500 000 | 400 000 | 300 000 |
| Cylindrical roller bearings | ||||
| – non-locating bearing | 1,5 | 450 000 | 300 000 | 150 000 |
| – locating bearing, without external axial loads | ||||
| or with light but alternating axial loads | 2 | 300 000 | 200 000 | 100 000 |
| – locating bearing, with constantly acting light axial load | 4 | 200 000 | 120 000 | 60 000 |
| – without a cage, full complement2) | 4 | NA3) | NA3) | 20 000 |
| Needle roller bearings | ||||
| – with a cage | 3
|
350 000
|
200 000
|
100 000
|
| Tapered roller bearings | 2 | 350 000 | 300 000 | 200 000 |
| Spherical roller bearings | ||||
| – when the load ratio Fa/Fr ≤ e and dm ≤ 800 mm | ||||
| series 213, 222, 238, 239 | 2 | 350 000 | 200 000 | 100 000 |
| series 223, 230, 231, 232, 240, 248, 249 | 2 | 250 000 | 150 000 | 80 000 |
| series 241 | 2 | 150 000 | 80 000 | 50 000 |
| – when the load ratio Fa/Fr ≤ e and dm > 800 mm | ||||
| series 238, 239 | 2 | 230 000 | 130 000 | 65 000 |
| series 230, 231, 232, 240, 248, 249 | 2 | 170 000 | 100 000 | 50 000 |
| series 241 | 2 | 100 000 | 50 000 | 30 000 |
| – when the load ratio Fa/Fr > e | ||||
| all series | 6 | 150 000 | 50 000 | 30 000 |
| CARB toroidal roller bearings | ||||
| – with a cage | 2 | 350 000 | 200 000 | 100 000 |
| – without a cage, full complement2) | 4 | NA3) | NA3) | 20 000 |
| Thrust ball bearings | 2 | 200 000 | 150 000 | 100 000 |
| Cylindrical roller thrust bearings | 10 | 100 000 | 60 000 | 30 000 |
| Needle roller thrust bearings | 10 | 100 000 | 60 000 | 30 000 |
| Spherical roller thrust bearings | ||||
| – rotating shaft washer | 4 | 200 000 | 120 000 | 60 000 |
- 1) The bearing factors and recommended ndm limits apply to bearings with standard internal geometry and standard cage execution. For alternative internal bearing design and special cage execution, contact the SKF application engineering service.
- 2) The tf value obtained from diagram a needs to be divided by a factor of 10.
- 3) Not applicable, as a bearing with a cage is recommended for these C/P values.
