Turbo-molecular pump

• US 20010055526A1
• Filed: 06/20/2001
• Published: 12/27/2001
• Est. Priority Date: 06/23/2000
• Status: Active Grant

• Current Assignee: Ebara Corporation
• Original Assignee: Ebara Corporation
• Inventors: Kawasaki, Hiroyuki
• Granted Patent: US 6,468,030 B2
• Time in Patent Office: Days
• US Class Current: 415/90
• CPC Class Codes: F04D 17/168 Pumps specially adapted to produce a vacuum
• CPC Class Codes: F04D 19/046 Combinations of two or more different types of pumps
• CPC Class Codes: F04D 29/28 for centrifugal or helico-centrifugal pumps for radial-flow or helico-centrifugal pumps
• CPC Class Codes: F04D 29/30 Vanes
• CPC Class Codes: F04D 29/4213 suction ports
• CPC Class Codes: F04D 29/441 especially adapted for elastic fluid pumps
• CPC Class Codes: F04D 29/444 Bladed diffusers
• CPC Class Codes: F05D 2250/51 Inlet

Abstract

A turbo-molecular pump evacuates gas with a rotor that rotates at a high speed. The turbo-molecular pump comprises a casing, a stator fixedly mounted in the casing and having stator blades, a rotor rotatably provided in the casing and having rotor blades alternating with the stator blades, and a radial turbine blade pumping section having a spiral ridge-groove section provided on at least one of surfaces, facing each other, of the stator blade and the rotor blade. At least one of the stator blade and the rotor blade which are located at a first stage of the radial turbine blade pumping section has such a shape that at least one of the stator blade and the rotor blade is smaller in thickness in a direction of gas flow.

Claims

1. A turbo-molecular pump comprising:

a casing;

a stator fixedly mounted in said casing and having stator blades;

a rotor rotatably provided in said casing and having rotor blades, said rotor blades alternating with said stator blades; and

a radial turbine blade pumping section having a spiral ridge-groove section provided on at least one of surfaces, facing each other, of said stator blade and said rotor blade;

wherein at least one of said stator blade and said rotor blade which are located at a first stage of said radial turbine blade pumping section has such a shape that said at least one of said stator blade and said rotor blade is smaller in thickness in a direction of gas flow.

2. A turbo-molecular pump according to

claim 1

, wherein said at least one of said stator blade and said rotor blade located at said first stage has such a shape as to be thinner in a tapered manner or a step-like manner.

3. A turbo-molecular pump comprising:

a casing;

a stator fixedly mounted in said casing and having stator blades;

a rotor rotatably provided in said casing and having rotor blades, said rotor blades alternating with said stator blades; and

a radial turbine blade pumping section having a spiral ridge-groove section provided on at least one of surfaces, facing each other, of said stator blade and said rotor blade;

wherein an outer diameter of said rotor at its portion facing an inner circumferential surface of a stator blade at a first stage in said radial turbine blade pumping section is smaller than an outer diameter of said rotor at its portion facing an inner circumferential surface of a stator blade at any one of stages subsequent to said first stage.

4. A turbo-molecular pump according to

claim 3

, wherein at least one of said stator blade and said rotor blade which are located at said first stage has such a shape that said at least one of said stator blade and said rotor blade is smaller in thickness in a direction of gas flow.

5. A turbo-molecular pump comprising:

a casing;

a stator fixedly mounted in said casing and having stator blades;

a rotor rotatably provided in said casing and having rotor blades, said rotor blades alternating with said stator blades; and

a radial turbine blade pumping section having a spiral ridge-groove section provided on at least one of surfaces, facing each other, of said stator blade and said rotor blade;

wherein one of an inner diameter of said stator and an outer diameter of said spiral ridge-groove section at its portion facing an outer circumferential surface of a rotor blade at a first stage in said radial turbine blade pumping section is larger than an inner diameter of said stator and an outer diameter of said spiral ridge-groove section at its portion facing an outer circumferential surface of a rotor blade at any one of stages subsequent to said first stage.

6. A turbo-molecular pump according to

claim 5

, wherein at least one of said stator blade and said rotor blade which are located at said first stage has such a shape that said at least one of said stator blade and said rotor blade is smaller in thickness in a direction of gas flow.

7. A turbo-molecular pump comprising:

a casing;

a stator fixedly mounted in said casing and having stator blades;

a rotor rotatably provided in said casing and having rotor blades, said rotor blades alternating with said stator blades; and

a radial turbine blade pumping section having a spiral ridge-groove section provided on at least one of surfaces, facing each other, of said stator blade and said rotor blade;

wherein an outer diameter of said rotor at its portion facing an inner circumferential surface of a stator blade at a first stage in said radial turbine blade pumping section is smaller than an outer diameter of said rotor at its portion facing an inner circumferential surface of a stator blade at any one of stages subsequent to said first stage; and

one of an inner diameter of said stator and an outer diameter of said spiral ridge-groove section at its portion facing an outer circumferential surface of a rotor blade at a first stage in said radial turbine blade pumping section is larger than an inner diameter of said stator and an outer diameter of said spiral ridge-groove section at its portion facing an outer circumferential surface of a rotor blade at any one of stages subsequent to said first stage.

8. A turbo-molecular pump according to

claim 7

, wherein at least one of said stator blade and said rotor blade which are located at said first stage has such a shape that said at least one of said stator blade and said rotor blade is smaller in thickness in a direction of gas flow.