Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 71948 ACD/P4AL
71948 ACD/P4AL
Dimensions
| d | 240 | mm | |
| D | 320 | mm | |
| B | 38 | mm | |
| d1 | 264.7 | mm | |
| d2 | 264.7 | mm | |
| D1 | 295.3 | mm | |
| b | 3.5 | mm | |
| C1 | 20.9 | mm | |
| C2 | 7.1 | mm | |
| C3 | 5.45 | mm | |
| r1,2 | min. | 2.1 | mm |
| r3,4 | min. | 1 | mm |
| a | 84.5 | mm |
Abutment dimensions
| da | min. | 251 | mm |
| db | min. | 251 | mm |
| Da | max. | 309 | mm |
| Db | max. | 315 | mm |
| ra | max. | 2 | mm |
| rb | max. | 1 | mm |
| dn | 271.4 | mm |
Calculation data
| Basic dynamic load rating | C | 216 | kN | |
| Basic static load rating | C0 | 305 | kN | |
| Fatigue load limit | Pu | 7.8 | kN | |
| Attainable speed for grease lubrication | 3200 | r/min | ||
| Attainable speed for oil-air lubrication | 4800 | r/min | ||
| Ball diameter | Dw | 25.4 | mm | |
| Number of balls | z | 31 | ||
| Reference grease quantity | Gref | 93 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 1350 | N | |
| Static axial stiffness, preload class A | 584 | N/µm | ||
| Preload class B | GB | 2700 | N | |
| Static axial stiffness, preload class B | 767 | N/µm | ||
| Preload class C | GC | 5400 | N | |
| Static axial stiffness, preload class C | 1029 | N/µm | ||
| Preload class D | GD | 10800 | N | |
| Static axial stiffness, preload class D | 1412 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.32 | ||
| Calculation factor | f1 | 0.98 | ||
| Calculation factor | f2A | 1 | ||
| Calculation factor | f2B | 1.04 | ||
| Calculation factor | f2C | 1.08 | ||
| Calculation factor | f2D | 1.14 | ||
| Calculation factor | fHC | 1 | ||
| Calculation factor | e | 0.68 | ||
| Calculation factor (single, tandem) | Y2 | 0.87 | ||
| Calculation factor (single, tandem) | Y0 | 0.38 | ||
| Calculation factor (single, tandem) | X2 | 0.41 | ||
| Calculation factor (back-to-back, face-to-face) | Y1 | 0.92 | ||
| Calculation factor (back-to-back, face-to-face) | Y2 | 1.41 | ||
| Calculation factor (back-to-back, face-to-face) | Y0 | 0.76 | ||
| Calculation factor (back-to-back, face-to-face) | X2 | 0.67 | ||
Mass
| Mass bearing | 8.5 | kg |