# US 2014/0154119 A1 · Internal gear pump

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- Number: US 2014/0154119 A1
- Document ID: US20140154119A1
- Status: Published application
- Kind: A1
- Application number: 14/088,220
- Filed: 2013-11-22
- Published: 2014-06-05
- Earliest claimed: 2012-11-30
- Assignees: Yamada Manufacturing Co., Ltd.
- Applicants: Yamada Manufacturing Co., Ltd
- Inventors: Masato Izutsu; Takatoshi Watanabe; Junichi Miyajima
- Web page: https://patentgrep.com/patent/US20140154119A1

## CPC

- F04C 28/22: by changing the eccentricity between cooperating members
- F04C 2/10: of internal-axis type with the outer member having more teeth or tooth-equivalents, e.g. rollers, than the inner member
- F04C 14/10: characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
- F04C 14/226: {by pivoting the cam around an eccentric axis}
- F04C 18/10: of internal-axis type with the outer member having more teeth or tooth equivalents, e.g. rollers, than the inner member
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS

## Abstract

The internal gear pump includes: an inner rotor; an outer rotor that rotates by having predetermined eccentricity to a rotation center of the inner rotor; an outer ring that holds the outer rotor in a freely rotatable state, and is also formed with at least three cam protruded parts; a pump housing having a rotor chamber; protruded-wall surface parts that are formed on an inner periphery side surface of the rotor chamber and are also formed in the same number as that of the cam protruded parts; and operation means for oscillating the outer ring. A diameter center of the holding-inner peripheral part of the outer ring is moved by the operation means along a locus of a circle of which a radius is the eccentricity to the rotation center of the inner rotor.

## Claims

### Claim 1

An internal gear pump comprising:
an inner rotor;
an outer rotor that rotates by having predetermined eccentricity to a rotation center of the inner rotor;
an outer ring that includes a holding-inner peripheral part which holds the outer rotor in a freely rotatable state, and at least three cam protruded parts formed along a circumferential direction of an outer periphery surface of the outer ring;
a pump housing that has a rotor chamber in which the outer ring is freely oscillatably arranged;
protruded-wall surface parts that are formed on an inner periphery side surface of the rotor chamber, are formed in the same number as that of the cam protruded parts, and are always brought into contact with the cam protruded parts; and
operation means for oscillating the outer ring, wherein
positions of the protruded-wall surface parts are set so that a diameter center of the holding-inner peripheral part of the outer ring is moved by the operation means along a locus of a circle of which a radius is the eccentricity to the rotation center of the inner rotor.

### Claim 2 (depends on 1)

The internal gear pump according to claim 1, wherein in contacting and sliding between the protruded-wall surface parts and the cam protruded parts, the protruded-wall surface parts are brought into point contact with the cam protruded parts at the same portions.

### Claim 3 (depends on 1)

The internal gear pump according to claim 1, wherein the protruded-wall surface parts have arc shapes at portions that are brought into contact with the cam protruded parts.

### Claim 4 (depends on 1)

The internal gear pump according to claim 1, wherein in the rotor chamber, stopper wall surface parts with which the cam protruded parts are brought into contact are formed to control an oscillation angle of the outer ring to be within a predetermined range.

### Claim 5 (depends on 2)

The internal gear pump according to claim 2, wherein the protruded-wall surface parts have arc shapes at portions that are brought into contact with the cam protruded parts.

### Claim 6 (depends on 2)

The internal gear pump according to claim 2, wherein in the rotor chamber, stopper wall surface parts with which the cam protruded parts are brought into contact are formed to control an oscillation angle of the outer ring to be within a predetermined range.

### Claim 7 (depends on 3)

The internal gear pump according to claim 3, wherein in the rotor chamber, stopper wall surface parts with which the cam protruded parts are brought into contact are formed to control an oscillation angle of the outer ring to be within a predetermined range.

### Claim 8 (depends on 5)

The internal gear pump according to claim 5, wherein in the rotor chamber, stopper wall surface parts with which the cam protruded parts are brought into contact are formed to control an oscillation angle of the outer ring to be within a predetermined range.