Bearings, units and housings -- Super-precision bearings -- Angular contact ball bearings -- Angular contact ball bearings, super-precision -- SKF 728 CD/P4A
728 CD/P4A
Dimensions
| d | 8 | mm | |
| D | 24 | mm | |
| B | 8 | mm | |
| d1 | 13.1 | mm | |
| d2 | 13.1 | mm | |
| D1 | 18.9 | mm | |
| r1,2 | min. | 0.3 | mm |
| r3,4 | min. | 0.2 | mm |
| a | 6.2 | mm |
Abutment dimensions
| da | min. | 10.4 | mm |
| db | min. | 10.4 | mm |
| Da | max. | 21.6 | mm |
| Db | max. | 22.2 | mm |
| ra | max. | 0.3 | mm |
| rb | max. | 0.2 | mm |
| dn | 14.3 | mm |
Calculation data
| Basic dynamic load rating | C | 3.71 | kN | |
| Basic static load rating | C0 | 1.37 | kN | |
| Fatigue load limit | Pu | 0.057 | kN | |
| Attainable speed for grease lubrication | 70000 | r/min | ||
| Attainable speed for oil-air lubrication | 110000 | r/min | ||
| Ball diameter | Dw | 4.762 | mm | |
| Number of balls | z | 8 | ||
| Reference grease quantity | Gref | 0.228 | cm³ | |
| Preload and stiffness (back-to-back, face-to-face) | ||||
| Preload class A | GA | 14 | N | |
| Static axial stiffness, preload class A | 12 | N/µm | ||
| Preload class B | GB | 28 | N | |
| Static axial stiffness, preload class B | 15 | N/µm | ||
| Preload class C | GC | 56 | N | |
| Static axial stiffness, preload class C | 21 | N/µm | ||
| Preload class D | GD | 112 | N | |
| Static axial stiffness, preload class D | 30 | N/µm | ||
| Calculation factors | ||||
| Calculation factor | f | 1.02 | ||
| 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 | 7.9 | ||
Mass
| Mass bearing | 0.017 | kg |