Patent ID: 8172515

Claim:
A turbo vacuum pump comprising: a suction part that sucks gas in an axial direction; a discharge part that discharges the gas sucked by the suction part, the discharge part having a plurality of rotating impellers and a stationary impeller arranged so as to be opposed to each of the plurality of rotating impellers; and a rotating shaft that rotates the plurality of rotating impellers, wherein the plurality of rotating impellers include at least one stage of a first turbine impeller for discharging the sucked gas in the axial direction, the first turbine impeller being radially affixed to a boss part, the boss part axially affixed to a suction-part-side end face of the rotating shaft, and at least one stage of a second turbine impeller radially affixed to the rotating shaft that extends through the second turbine impeller, the second turbine impeller being arranged downstream of the first turbine impeller.