Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 7228 CD/HCP4A
7228 CD/HCP4A
Dimensions
| d | 140 | mm | |
| D | 250 | mm | |
| B | 42 | mm | |
| d1 | 176.8 | mm | |
| d2 | 176.8 | mm | |
| D1 | 213.2 | mm | |
| r1,2 | min. | 3 | mm |
| r3,4 | min. | 1.5 | mm |
| a | 47.3 | mm |
Abutment dimensions
| da | min. | 154 | mm |
| db | min. | 154 | mm |
| Da | max. | 236 | mm |
| Db | max. | 241 | mm |
| ra | max. | 2.5 | mm |
| rb | max. | 1.5 | mm |
| dn | 184.8 | mm |
Calculation data
| Basic dynamic load rating | C | 221 | kN | |
| Basic static load rating | C0 | 240 | kN | |
| Fatigue load limit | Pu | 7.35 | kN | |
| Attainable speed for grease lubrication | 7000 | r/min | ||
| Attainable speed for oil-air lubrication | 10000 | r/min | ||
| Ball diameter | Dw | 30.162 | mm | |
| Number of balls | z | 18 | ||
| Reference grease quantity | Gref | 83.931 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 850 | N | |
| Static axial stiffness, preload class A | 181 | N/µm | ||
| Preload class B | GB | 1700 | N | |
| Static axial stiffness, preload class B | 245 | N/µm | ||
| Preload class C | GC | 3400 | N | |
| Static axial stiffness, preload class C | 339 | N/µm | ||
| Preload class D | GD | 6800 | N | |
| Static axial stiffness, preload class D | 485 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.09 | ||
| Calculation factor | f1 | 1 | ||
| Calculation factor | f2A | 1 | ||
| Calculation factor | f2B | 1.01 | ||
| Calculation factor | f2C | 1.03 | ||
| Calculation factor | f2D | 1.06 | ||
| Calculation factor | fHC | 1.01 | ||
| Calculation factor | f0 | 15.2 | ||
Mass
| Mass bearing | 6.92 | kg |