Patent ID: 6559568
Filing Date: 2003-05-06
Classification: F04D,F16C

Abstract:
A magnetic bearing type vacuum pump comprising:a cylindrical casing having a suction port and an exhaust port; a stator disposed within the casing; a shaft rotatably supported within the casing; a rotor attached to the shaft to be rotated together with the shaft; a motor for rotationally driving the shaft; a magnetic bearing portion including a plurality of electromagnets disposed around a predetermined portion of the shaft with a predetermined gap from the shaft, and an electromagnet target formed on a portion of the shaft confronted with the electromagnets; a radial sensor portion disposed in the vicinity of the magnetic bearing portion and including a radial sensor disposed around the shaft with a predetermined gap therefrom, and a radial sensor target formed on a portion of the shaft confronted with the radial sensor; a thrust bearing portion for holding the shaft in a thrust direction; and a collar disposed on the shaft between the electromagnet target and the radial sensor target, the collar being formed of laminated steel plates laminated through insulations.