| 摘要 |
PURPOSE:To give a bearing a preload with less vibration and secular change by installing a magnetic member, whose one side at least is magnet, at the inner or outer ring of each of two mating bearings, and by moving the rings relatively by the use of magnetic force acting between the two magnetic members. CONSTITUTION:This bearing device is equipped with an armature coil 1, core 2, bracket 3, upper and lower bearings 4, 5, a shaft 6, a rotor magnet 7, and rotor 8. Here an upper preloading magnet 19 whose bearing side is magnetized in N is fixed under the inner ring of the upper bearing 4 which is movable axially. A lower preloading magnet 20 whose bearing side is magnetized in S is fixed over the inner ring of the lower bearing 5. These bearings 4, 5 are preloaded through utilization of the attraction force of magnets 19, 20, respectively. This construction is free from any contacting parts such as preload spring to enable preloading with little secular change without risk of generating vibrations.
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