# US 11,898,565 B2 · Vacuum pump and linked-type thread groove spacer

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- Number: US 11,898,565 B2
- Document ID: US11898565B2
- Status: Granted
- Kind: B2
- Application number: 17/611,362
- Filed: 2020-05-22
- Published: 2022-07-21
- Granted: 2024-02-13
- Earliest claimed: 2019-05-31
- Assignees: Edwards Japan Limited
- Applicants: Edwards Japan Limited
- Inventors: Kengo Saegusa; Nahoko Yoshihara; Yoshinobu Ohtachi
- Web page: https://patentgrep.com/patent/US11898565B2

## CPC

- F04D 19/042: {Turbomolecular vacuum pumps}
- F04D 19/044: {Holweck-type pumps}
- F04D 29/5853: {heat insulation or conduction}
- F04D 29/644: {especially adapted for elastic fluid pumps}
- F04D 29/646: {Mounting or removal of fans}
- F04D 19/048: {comprising magnetic bearings}
- F04D 29/522: {especially adapted for elastic fluid pumps}
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)

## Abstract

A vacuum pump which can prevent lowering of an exhaust performance of the vacuum pump, even if a linked-type thread groove spacer is fastened by a fixing bolt, is provided. The linked-type thread groove spacer according to an embodiment of the present invention includes a structure for linking a Siegbahn pump portion and a thread-groove pump portion. When this linked-type thread groove spacer is to be fastened, a countersunk hole is provided in advance in an exhaust channel portion, and the linked-type thread groove spacer is fastened to a base by a fixing bolt. As a result, a head part of the fixing bolt does not protrude to the exhaust channel, and the head part of the fixing bolt does not make resistance against an exhaust gas. Thus, lowering of the exhaust performance of the vacuum pump can be suppressed.

## Claims

### Claim 1

A vacuum pump comprising: a casing in which an inlet port or an outlet port is formed, a stator component enclosed in the casing, a Siegbahn pump portion comprising a stator comprising a spiral groove having a first ridge portion, a second ridge portion and a root portion positioned between an outer side in a radial direction of the first ridge portion and inner side in the radial direction of the second ridge portion, and a thread-groove pump portion, wherein a linked-type thread groove spacer comprises the Siegbahn pump portion and the thread-groove pump portion and the linked-type thread groove spacer links the Siegbahn pump portion and the thread-groove pump portion; and a countersunk hole is provided in an exhaust channel surface of the root portion in the
Siegbahn pump portion in the linked-type thread groove spacer, and the linked- type thread groove spacer and the casing or the stator component are fastened by a fixing bolt disposed in the countersunk hole wherein the countersunk hole is positioned closer to the outer side of the first ridge portion than the inner side of the second ridge portion.

### Claim 2 (depends on 1)

The vacuum pump according to claim 1, wherein
a heating means for heating the thread-groove pump portion is provided on the casing or the stator component; and
the fixing bolt is disposed in contact with a high-temperature portion of the casing or the stator component heated by the heating means.

### Claim 3 (depends on 2)

The vacuum pump according to claim 2, wherein
the fixing bolt has a material with greater heat conductivity than that of an iron bolt.

### Claim 4 (depends on 1)

The vacuum pump according to claim 1, wherein the fixing bolt is covered with a cap.

### Claim 5

A linked-type thread groove spacer which is used in a vacuum pump having a casing in which an inlet port or an outlet port is formed, and a stator component enclosed in the casing, the linked-type thread groove spacer comprising:
a Siegbahn pump portion comprising a spiral groove comprising a first ridge portion, a second ridge portion and a root portion positioned between an outer side in a radial direction of the first ridge portion and inner side in the radial direction of the second ridge portion; and
a thread-groove pump portion linked to the Siegbahn pump portion, wherein
the linked-type thread groove spacer has a countersunk hole for a fixing bolt provided in an exhaust channel surface of the root portion in the Siegbahn pump portion, and is fastened to the casing or the stator component by the fixing bolt, wherein the countersunk hole is positioned closer to the outer side of the first ridge portion than the inner side of the second ridge portion.