Patent ID: 11946482
Assignee: EDWARDS JAPAN LIMITED
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 0:
1. A vacuum pump, comprising:
a casing having an inlet port and an outlet port;
a rotor having a rotating shaft;
a magnetic bearing which rotatably supports the rotating shaft; and
a motor which rotates/drives the rotating shaft; and
wherein the vacuum pump is configured to transfer a gas taken in through the inlet port to the outlet port by rotation of the rotor,
wherein a value of γ expressed in an expression below is larger than 1, and
wherein at least one natural frequency of the rotor increases without matching a rotational frequency of the rotating shaft when the rotational frequency of the rotating shaft increases:

γ=Jz/J 

wherein, for the above expression, Jz is an inertia moment around an axis of the rotating shaft of the rotor, and J is the inertia moment around an axis orthogonal to the axis of the rotating shaft of the rotor.