Abstract: A vacuum pump has a pump case having a gas suction port at an upper surface thereof, a rotor shaft mounted in the pump case for undergoing rotation, and a rotor connected to the rotor shaft for rotation therewith. The rotor has inner and outer circumferential surfaces coated with a corrosion-resistant film treated by nonelectrolytic plating. Rotor blades are disposed in the pump case and are integrally connected to the outer circumferential surface of the rotor. Stator blades are integrally connected to the pump case so that the rotor blades and the stator blades are alternately positioned and arranged. A balancing body is disposed on the inner circumferential surface of the rotor for balancing the rotor during rotation thereof.

Abstract: A vacuum pump has a pump case (1) forming a gas suction port (2) at the upper surface thereof; a rotor shaft (5) rotatably supported in the pump case; a rotor (8) being formed a corrosion-resistant film treated by nonelectrolytic plating on the inner and outer circumferential surfaces (8b, 8a) of the rotor; a plurality of rotor blades (10) accommodated in the pump case and integrally formed with an outer circumferential surface of the rotor; a plurality of stator blades (11) fixed in the pump case such that the rotor blades and the stator blades are alternately positioned and arranged; a drive motor (9) for rotating the rotor shaft; and mass-addition means (15) formed by applying an adhesive or a coating, having heat and corrosion resistances, on the inner circumferential surface of the rotor.

Abstract: To provide a magnetic bearing type vacuum pump, which can suppress the generation of eddy current on a shaft to be small in heat generation on the shaft and to be excellent in efficiency. In a shaft, an electromagnet target composing a target for electromagnets composing a radial magnetic bearing portion, a radial sensor target composing a target for a coil detecting a displacement of the shaft in the vicinity of the magnetic bearing portion and a collar between the electromagnet target and the radial sensor target are composed of laminated steel plates, so that the generation of eddy current caused on the shaft due to magnetic field generated in the magnetic bearing portion is reduced.

Abstract: To provide a magnetic bearing type vacuum pump, which can suppress the generation of eddy current on a shaft to be small in heat generation on the shaft and to be excellent in efficiency. In a shaft, an electromagnet target composing a target for electromagnets composing a radial magnetic bearing portion, a radial sensor target composing a target for a coil detecting a displacement of the shaft in the vicinity of the magnetic bearing portion and a collar between the electromagnet target and the radial sensor target are composed of laminated steel plates, so that the generation of eddy current caused on the shaft due to magnetic field generated in the magnetic bearing portion is reduced.