| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic bearing type vacuum pump not magnetizing an inner ring of a bearing at a time of pump assembly and preventing following rotation of the inner ring in pump operation. SOLUTION: A rotor 4 having a rotary blade 21 formed thereon is attached on a shaft 2 having a motor rotor 3 of a DC blushless motor built therein. A rotating body which consists of the rotor 4 and the shaft 2 is supported by electromagnets 51, 52, 53 constructing a magnetic bearing without contact. The shaft 2 is installed to be inserted through emergency mechanical bearings 27, 28 provided on a stator 5. The inner ring 27b and a rolling elements 27a of the mechanical bearing 27 is formed out of nonmagnetic material or soft magnetic material. As a result, the inner ring 27b is not magnetized due to influence of magnetic force of the motor rotor 3 at a time of pump assembly, and following rotation of the inner ring 27b of the mechanical bearing 27 can be prevented in pump operation. COPYRIGHT: (C)2007,JPO&INPIT
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