摘要 |
PURPOSE: A ball bearing and a turbo-molecular pump comprising the same are provided to enhance cooling efficiency by a separate cooling device. CONSTITUTION: A ball bearing comprises an outer wheel(120), an inner wheel(110), a ball(130) and a fluid circulating unit(140). The inner wheel is held in the outer wheel and forms a space along with the outer wheel. The ball is held in the space. The fluid circulating unit is formed on at least one of the inner and outer wheels and discharges fluid from the space. The fluid circulating unit is formed on at least one of the outer surface of the inner wheel and the inner surface of the outer wheel in a radial direction. |