US 2001/0012488 A1Published application

Vaccum pump

AssigneeSeiko Instruments Inc.

InventorsYoshinobu Ohtachi, Hirotaka Namiki, Akira Yamauchi

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Abstract

There is provided a vacuum pump which suppresses the propagation of vibrations to an external container without the use of a damper. The vacuum pump has an outer cylindrical portion, a rotor portion and a stator portion accommodated within the outer cylindrical portion to define a transferring portion for a gas sucked from an inlet port, a magnetic bearing for supporting the rotor portion with respect to the stator portion, a motor for rotating the rotor portion with respect to the stator portion, and a base for supporting the outer cylindrical portion and the stator portion. A vibration absorbing member is interposed between the stator portion and the base, which has a natural frequency F=(f1+f3)/2±(f1−f3)/4, provided that f1, f2 and f3 respectively denote a natural frequency of nutation in conical mode, a natural frequency in parallel mode and a natural frequency of procession in the conical mode, when the rotor portion is rotated at a rated speed.

Claims12

Dependent claims

A vacuum pump comprising:

an outer cylindrical portion to be connected to an external container, the outer cylindrical portion having one end portion provided with an inlet port through which a gas within the external container is sucked;
a rotor portion rotatably accommodated within the outer cylindrical portion;
a stator portion disposed within the outer cylindrical portion, the stator portion and the rotor portion cooperatively defining a transferring portion for transferring the gas sucked through the inlet port;
a magnetic bearing for floatingly supporting the rotor portion;
a motor portion for rotatingly driving the rotor portion;
a base supporting the outer cylindrical portion and the stator portion at the other end portion of the outer cylindrical member;
and
a vibration absorbing member, interposed between at least one of the outer cylindrical portion and the stator portion and the base, for displaceably supporting the at least one of the outer cylindrical portion and the stator portion with respect to the base,
wherein the vibration absorbing member has a natural frequency F meeting the following formula:
F=(f1+f3)/2±(f1−f3)/4
where f1, f2 and f3 respectively denote a natural frequency of nutation in conical mode, a natural frequency in parallel mode and a natural frequency of procession in the conical mode, when the rotor portion is rotated at a rated speed.

8 more elements

A vacuum pump comprising:

a flange portion to be connected to an external container, the flange portion having an inlet port through which a gas within the external container is sucked;
an outer cylindrical portion having one end side connected to or integral with the flange portion;
a base connected to the other end side of the outer cylindrical portion, the base, the flange portion and the outer cylindrical portion cooperatively defining a hollow portion communicating with an interior of the external container through the inlet port;
a stator portion supported to the base, and accommodated within the hollow portion;
a rotor portion accommodated within the hollow portion;
a bearing rotatably supporting the rotor portion with respect to the stator portion;
a motor portion for rotatingly driving the rotor portion, supported by the bearing, with respect to the stator portion;
and
vibration absorbing means, including a material having a vibration absorbing property, for reducing propagation of vibration using elastic and/or viscous property, the vibration absorbing means being disposed at at least one of the flange portion, the outer cylindrical portion, the base, the stator portion, and joint portions respectively connecting two members selected from the flange portion, the outer cylindrical portion, the base, and the stator portion.

6 more elements

Dependencies are inferred from the claim text.