Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 71921 CD/P4A
71921 CD/P4A
Dimensions
| d | 105 | mm | |
| D | 145 | mm | |
| B | 20 | mm | |
| d1 | 117.3 | mm | |
| d2 | 117.3 | mm | |
| D1 | 132.7 | mm | |
| r1,2 | min. | 1.1 | mm |
| r3,4 | min. | 0.6 | mm |
| a | 26.8 | mm |
Abutment dimensions
| da | min. | 111 | mm |
| db | min. | 111 | mm |
| Da | max. | 139 | mm |
| Db | max. | 141 | mm |
| ra | max. | 1 | mm |
| rb | max. | 0.6 | mm |
| dn | 120.6 | mm |
Calculation data
| Basic dynamic load rating | C | 61.8 | kN | |
| Basic static load rating | C0 | 69.5 | kN | |
| Fatigue load limit | Pu | 2.6 | kN | |
| Attainable speed for grease lubrication | 8500 | r/min | ||
| Attainable speed for oil-air lubrication | 14000 | r/min | ||
| Ball diameter | Dw | 12.7 | mm | |
| Number of balls | z | 27 | ||
| Reference grease quantity | Gref | 11.1 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 230 | N | |
| Static axial stiffness, preload class A | 110 | N/µm | ||
| Preload class B | GB | 460 | N | |
| Static axial stiffness, preload class B | 151 | N/µm | ||
| Preload class C | GC | 920 | N | |
| Static axial stiffness, preload class C | 215 | N/µm | ||
| Preload class D | GD | 1840 | N | |
| Static axial stiffness, preload class D | 316 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.25 | ||
| Calculation factor | f1 | 1 | ||
| Calculation factor | f2A | 1 | ||
| Calculation factor | f2B | 1.04 | ||
| Calculation factor | f2C | 1.09 | ||
| Calculation factor | f2D | 1.15 | ||
| Calculation factor | fHC | 1 | ||
| Calculation factor | f0 | 16.4 | ||
Mass
| Mass bearing | 0.82 | kg |