| 摘要 |
PROBLEM TO BE SOLVED: To provide a vacuum pump utilizing a change in the magnetic permeability of a ferromagnetic material for determining the temperature of a rotor while improving the durability of the ferromagnetic material and suppressing an increase in the number of components. SOLUTION: A target 43 formed of the ferromagnetic material is arranged near the shaft on the bottom face of a nut 42 provided at the lower end of a shaft 3 to which the rotor is fixed. The influence of centrifugal force is therefore reduced. On a stator side, an inductance type gap sensor 44 is provided in opposition to the target 43. When the temperature of the rotor rises and the temperature of the target 43 is a Curie temperature or higher, the magnetic permeability of the target 43 is reduced. A change in the magnetic permeability is detected as a change in inductance by the gap sensor 44 and a rotor temperature monitor signal is output from a detection part 31 to a motor drive control part 33 and an alarm part 34. COPYRIGHT: (C)2006,JPO&NCIPI
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