| 摘要 |
An oil-free turbo vacuum pump is capable of evacuating gas in a chamber from atmospheric pressure to high vacuum. The turbo vacuum pump includes a pumping section having rotor blades and stator blades which are disposed alternately in a casing, and a main shaft for supporting the rotor blades. A gas bearing is used as a bearing for supporting the main shaft in a thrust direction, spiral grooves are formed in both surfaces of a stationary part of the gas bearing, and the stationary part having the spiral grooves is placed between an upper rotating part and a lower rotating part which are fixed to the main shaft. A thrust magnetic bearing for canceling out a thrust force generated by the differential pressure between a discharge side and an intake side by an evacuation action of the pumping suction is provided.
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