Precision bearing fit

Precision bearing fit
In order to ensure that the bearing does not produce excessive deformation after installation, it must be done:
(1) The roundness of the shaft and the seat hole and the verticality of the shoulder should be required according to the corresponding precision of the bearing.
(2) It is necessary to accurately calculate the interference of the rotating ferrule and the appropriate fit of the fixed ferrule.
The amount of interference of the rotating ring should be as small as possible. As long as the influence of thermal expansion at the working temperature and the influence of centrifugal force at the highest speed are ensured, it will not cause creep or sliding of the tight fit surface. According to the size of the working load and the size of the bearing, the fixed ring selects a very small clearance fit or interference fit. Too loose or too tight is not conducive to maintaining the original and accurate shape.
(3) If the bearing operates under high-speed conditions and the working temperature is high, special attention should be paid to the fit of the rotating ring not being too loose to prevent eccentric vibration, and the fit of the fixed ring to prevent gaps from occurring. Deforms under load and excites vibrations.
(4) The condition for adopting a small interference fit for the fixed ring is that both sides of the matching surface have high shape accuracy and small roughness, otherwise it will make installation difficult and disassembly more difficult. In addition, the influence of thermal elongation of the spindle needs to be considered .
(5) The main shaft using a pair of double angular contact ball bearings is mostly light-loaded. If the fit interference is too large, the internal axial preload will be significantly larger, causing adverse effects. The main shaft using double-row short cylindrical roller bearings and the main shaft of tapered roller bearings have relatively large loads, so the fit interference is also relatively large.