Motor and turbo-molecular pump
AssigneeIbiden Co., Ltd.
InventorsHirokazu Yashiro, Youichi Kuwayama
Life of this patent
Estimating the term…
Abstract
A compact turbo-molecular pump having a high depressurizing capability. A motor for rotating a rotor vane includes an air bearing. The air bearing has a rotary cylinder and a fixed surface surrounding the rotary cylinder. The material of the rotary cylinder has a coefficient of thermal expansion that is smaller than that of the material of the fixed surface. Thus, change in the dimensions of the rotary cylinder is smaller than that of the fixed surface even if the temperature of the air bearing rises during operation of the pump. Thus, the rotary cylinder avoids contact with the fixed surface.
Claims20
A motor provided in a turbo-molecular pump, comprising:
- a rotary shaft including a magnet;
- and
- a bearing for radially supporting the rotary shaft, wherein the bearing includes:
- a cylindrical rotary member connected To The rotary shaft over the magnet;
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is spaced from the rotary member by a predetermined distance, and wherein the materials of the rotary member and the fixed surface are selected so that the material of the rotary member has a coefficient of thermal expansion that is smaller than that of the material of the fixed surface;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A motor provided in a turbo-molecular pump, comprising:
- a rotary shaft including a magnet;
- a bearing for radially supporting the rotary shaft, wherein the bearing includes:
- a cylindrical rotary member connected to the rotary shaft over the magnet;
- and
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is spaced from the rotary member by a predetermined distance, and wherein the rotary member is made of a material having a coefficient of thermal expansion that is 5×10−6/° C. or less;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A turbo-molecular pump comprising:
- a housing;
- a stator vane attached to the housing;
- a rotor vane rotated relative to the stator vane;
- and
- a motor for driving the rotor vane, wherein the motor includes:
- a motor shaft including a magnet;
- and
- a bearing for radially supporting the rotary shaft, wherein the bearing includes:
- a cylindrical rotary member connected to the rotary shaft over the magnet;
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is spaced from the rotary member by a predetermined distance, and wherein the material of the rotary member has a coefficient of thermal expansion that is smaller than that of the material of the fixed surface;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A turbo-molecular pump comprising:
- a housing;
- a stator vane attached to the housing;
- a rotor vane rotated relative to the stator vane;
- and
- a motor for driving the rotor vane, wherein the motor includes:
- a rotary shaft including a magnet;
- and
- a bearing for radially supporting the rotary shaft, wherein the bearing includes:
- a cylindrical rotary member connected to the rotary shaft over the magnet;
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is spaced from the rotary member by a predetermined distance, and wherein the rotary member is made of a material having a coefficient of thermal expansion that is 5×10−6/° C. or less, and which is smaller than the coefficient of thermal expansion of the material of the fixed surface;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A method for producing a brushless motor of a turbo-molecular pump having a rotary shaft including a magnet and an air bearing, wherein the air bearing includes a cylindrical rotary member connected to the rotary shaft over the magnet, and a cylindrical fixed surface covering the rotary shaft, the method comprising the step of:
- selecting materials for the rotary member and the fixed surface so that the material of the rotary member has a coefficient of thermal expansion that is smaller than that of the material of the fixed surface;
- and
- assembling the rotary member and the fixed surface so that the fixed surface surrounds the rotary member and the fixed surface is spaced from the rotary member by a predetermined distance.
A motor provided in a compressor comprising:
- a rotary shaft including a magnet;
- and
- a bearing for radially supporting the rotary shaft, wherein the bearing includes:
- a cylindrical rotary member connected to the rotary shaft over the magnet;
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is space from the rotary member by a predetermined distance, and wherein the materials of the rotary member and the fixed surface are selected so that the material of the rotary member has a coefficient of thermal expansion that is smaller than that of the materials of the fixed surface;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A motor provided in a compressor, comprising:
- a rotary shaft including a magnet;
- a bearing for radially supporting the rotary shaft wherein the bearing includes:
- a cylindrical rotary member connected to the rotary shaft over the magnet;
- and
- a cylindrical fixed surface surrounding the rotary member, wherein the fixed surface is spaced from the rotary member by a predetermined distance, and wherein the rotary member is made of a material having a coefficient of thermal expansion that is 5×10−6/° C. or less;
- and
- armature coils arranged about a peripheral surface of the fixed surface to rotate the rotary shaft.
A method for producing a brushless motor of a compressor having a rotary shaft and an air bearing, wherein the air bearing includes a cylindrical rotary member connected to the rotary shaft, and a cylindrical fixed surface covering the rotary shaft, the method comprising the step of:
- selecting materials for the rotary member and the fixed surface so that the material of the rotary member has a coefficient of thermal expansion that is smaller than that of the material of the fixed surface;
- and
- assembling the rotary member and the fixed surface so that the fixed surface surrounds the rotary member and the fixed surface is spaced from the rotary member by a predetermined distance.
Dependencies are inferred from the claim text.