Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 7221 CD/P4A
7221 CD/P4A
Dimensions
| d | 105 | mm | |
| D | 190 | mm | |
| B | 36 | mm | |
| d1 | 131.2 | mm | |
| d2 | 131.2 | mm | |
| D1 | 163.8 | mm | |
| r1,2 | min. | 2.1 | mm |
| r3,4 | min. | 1.1 | mm |
| a | 37.9 | mm |
Abutment dimensions
| da | min. | 117 | mm |
| db | min. | 117 | mm |
| Da | max. | 178 | mm |
| Db | max. | 183 | mm |
| ra | max. | 2 | mm |
| rb | max. | 1 | mm |
| dn | 138.4 | mm |
Calculation data
| Basic dynamic load rating | C | 172 | kN | |
| Basic static load rating | C0 | 153 | kN | |
| Fatigue load limit | Pu | 5.3 | kN | |
| Attainable speed for grease lubrication | 7500 | r/min | ||
| Attainable speed for oil-air lubrication | 12000 | r/min | ||
| Ball diameter | Dw | 26.988 | mm | |
| Number of balls | z | 15 | ||
| Reference grease quantity | Gref | 48.333 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 650 | N | |
| Static axial stiffness, preload class A | 129 | N/µm | ||
| Preload class B | GB | 1300 | N | |
| Static axial stiffness, preload class B | 174 | N/µm | ||
| Preload class C | GC | 2600 | N | |
| Static axial stiffness, preload class C | 243 | N/µm | ||
| Preload class D | GD | 5200 | N | |
| Static axial stiffness, preload class D | 349 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.08 | ||
| Calculation factor | f1 | 1 | ||
| Calculation factor | f2A | 1 | ||
| Calculation factor | f2B | 1.01 | ||
| Calculation factor | f2C | 1.03 | ||
| Calculation factor | f2D | 1.05 | ||
| Calculation factor | fHC | 1 | ||
| Calculation factor | f0 | 14.5 | ||
Mass
| Mass bearing | 3.87 | kg |