Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 7028 ACD/P4A
7028 ACD/P4A
Dimensions
| d | 140 | mm | |
| D | 210 | mm | |
| B | 33 | mm | |
| d1 | 161.6 | mm | |
| d2 | 161.6 | mm | |
| D1 | 188.4 | mm | |
| r1,2 | min. | 2 | mm |
| r3,4 | min. | 1 | mm |
| a | 57.5 | mm |
Abutment dimensions
| da | min. | 149 | mm |
| db | min. | 149 | mm |
| Da | max. | 201 | mm |
| Db | max. | 205 | mm |
| ra | max. | 2 | mm |
| rb | max. | 1 | mm |
| dn | 166.3 | mm |
Calculation data
| Basic dynamic load rating | C | 146 | kN | |
| Basic static load rating | C0 | 156 | kN | |
| Fatigue load limit | Pu | 5.1 | kN | |
| Attainable speed for grease lubrication | 5600 | r/min | ||
| Attainable speed for oil-air lubrication | 8500 | r/min | ||
| Ball diameter | Dw | 22.225 | mm | |
| Number of balls | z | 22 | ||
| Reference grease quantity | Gref | 45 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 900 | N | |
| Static axial stiffness, preload class A | 364 | N/µm | ||
| Preload class B | GB | 1800 | N | |
| Static axial stiffness, preload class B | 477 | N/µm | ||
| Preload class C | GC | 3600 | N | |
| Static axial stiffness, preload class C | 633 | N/µm | ||
| Preload class D | GD | 7200 | N | |
| Static axial stiffness, preload class D | 856 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.16 | ||
| Calculation factor | f1 | 0.99 | ||
| Calculation factor | f2A | 1 | ||
| Calculation factor | f2B | 1.02 | ||
| Calculation factor | f2C | 1.05 | ||
| Calculation factor | f2D | 1.08 | ||
| 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 | 3.42 | kg |