Patent ID: 9470235
Filing Date: 2016-10-18
CPC Classification: F04D

Claim Text:
1. A vacuum pump comprising: an exhaust portion having a plurality of rotating blade portions arranged in multiple stages, each of the rotating blade portions having a plurality of rotor blades, and a plurality of stationary blade portions arranged between the rotating blade portions, in which outer circumferential rims are supported via spacers, each of the stationary blade portions having a plurality of stator blades, wherein in at least one stationary blade portion among the plurality of stationary blade portions, a blade height on the inner circumferential side of the plurality of stator blades provided in the stationary blade portion is set to be smaller than a blade height on the outer circumferential side of the plurality of stator blades, and in the at least one stationary blade portion the gap between the upper surface of the stationary blade portion on the inner circumferential side and the lower surface of the rotating blade portion on the upper stage side is larger than the gap between the lower surface of the stationary blade portion on the inner circumferential side and the upper surface of the rotating blade portion on the lower stage side, the stationary blade portion is supported by the spacers in such a manner that the inner circumferential side of the stationary blade portion is floated up toward an intake port side.