# US 2018/0320712 A1 · Rotary Piston Type Actuator

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- Number: US 2018/0320712 A1
- Document ID: US20180320712A1
- Status: Published application
- Kind: A1
- Application number: 16/036,344
- Filed: 2018-07-16
- Published: 2018-11-08
- Earliest claimed: 2013-02-27
- Assignees: Woodward, Inc.
- Applicants: Woodward, Inc.
- Inventors: Joseph H. Kim; Robert P. O`Hara; Shahbaz H. Hydari; Pawel A. Sobolewski
- Web page: https://patentgrep.com/patent/US20180320712A1

## CPC

- F15B 15/06: for mechanically converting rectilinear movement into non- rectilinear movement
- F15B 15/125: {of the curved-cylinder type}
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

A rotary actuator includes a first housing defining a first arcuate chamber having a first cavity, a first fluid port in fluid communication with the first cavity, and an open end. A rotor assembly is rotatably journaled in the first housing and having a rotary output shaft and a first rotor arm extending radially outward from the rotary output shaft. An arcuate-shaped first piston is disposed in the first housing for reciprocal movement in the first arcuate chamber through the open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a first portion of the first piston contacts the first rotor arm.

## Claims

### Claim 1

A rotary actuator comprising:
a first housing defining a first arcuate chamber comprising a first cavity, a first fluid port in fluid communication with the first cavity, and an open end;
a rotor assembly rotatably journaled in said first housing and comprising a rotary output shaft and a first rotor arm extending radially outward from the rotary output shaft; and
an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first arcuate chamber through the open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a first portion of the first piston contacts the first rotor arm.

### Claim 2 (depends on 1)

The rotary actuator of claim 1, wherein the first housing further defines a second arcuate chamber comprising a second cavity, and a second fluid port in fluid communication with the second cavity;
the rotor assembly further comprises a second rotor arm;
the rotary actuator further comprising an arcuate-shaped second piston disposed in said first housing for reciprocal movement in the second arcuate chamber, wherein a second seal, the second cavity, and the second piston define a second pressure chamber, and a first portion of the second piston contacts the second rotor arm.

### Claim 3 (depends on 2)

The rotary actuator of claim 2, wherein the second piston is oriented in the same rotational direction as the first piston.

### Claim 4 (depends on 2)

The rotary actuator of claim 2, wherein the second piston is oriented in the opposite rotational direction as the first piston.

### Claim 5 (depends on 1)

The rotary actuator of claim 1, wherein application of pressurized fluid to the first pressure chamber urges the first piston partially outward from the first pressure chamber to urge rotation of the rotary output shaft in a first direction, and rotation of the rotary output shaft in a second direction opposite that of the first direction urges the first piston partially into the first pressure chamber to urge pressurized fluid out the first fluid port.

### Claim 6 (depends on 1)

The rotary actuator of claim 1, further comprising a second housing disposed about the first housing and having a second fluid port, wherein the first housing, the second housing, the seal, and the first piston define a second pressure chamber.

### Claim 7 (depends on 6)

The rotary actuator of claim 6, wherein application of pressurized fluid to the first pressure chamber urges the first piston partially outward from the first pressure chamber to urge rotation of the rotary output shaft in a first direction, wherein application of pressurized fluid to the second pressure chamber urges the first piston partially into the first pressure chamber to urge rotation of the rotary output shaft in a second direction opposite from the first direction.

### Claim 8 (depends on 1)

The rotary actuator of claim 1, wherein the first seal is disposed about an interior surface of the open end.

### Claim 9 (depends on 1)

The rotary actuator of claim 1, wherein the first seal is disposed about the periphery of the first piston.

### Claim 10 (depends on 1)

The rotary actuator of claim 1, wherein the first seal provides load bearing support for the first piston.

### Claim 11 (depends on 1)

The rotary actuator of claim 1, wherein the first housing is formed as a one-piece housing.

### Claim 12 (depends on 1)

The rotary actuator of claim 1, wherein the first seal is a one-piece seal.

### Claim 13 (depends on 1)

The rotary actuator of claim 1, wherein the first piston is solid in cross-section.

### Claim 14 (depends on 1)

The rotary actuator of claim 1, wherein the first piston is at least partly hollow in cross-section.

### Claim 15 (depends on 14)

The rotary actuator of claim 14, wherein a structural member inside the first piston is located between two cavities inside the first piston.

### Claim 16 (depends on 1)

The rotary actuator of claim 1, wherein the first piston has one of a square, rectangular, ovoid, elliptical, or circular shape in cross-section.

### Claim 17 (depends on 2)

The rotary actuator of claim 2, the first housing further defines a fluid port fluidically connecting the first cavity and the second cavity.

### Claim 18 (depends on 1)

The rotary actuator of claim 1, wherein the first arcuate chamber defines at least a portion of an ellipse having a plane, wherein a rotational axis of the output shaft is not perpendicular to the plane.

### Claim 19

A method of rotary actuation comprising:
providing a rotary actuator comprising:
a first housing defining a first arcuate chamber comprising a first cavity, a first fluid port in fluid communication with the first cavity, and an open end;
a rotor assembly rotatably journaled in said first housing and comprising a rotary output shaft and a first rotor arm extending radially outward from the rotary output shaft; and an arcuate-shaped first piston disposed in said first housing for reciprocal movement in the first arcuate chamber through the open end, wherein a first seal, the first cavity, and the first piston define a first pressure chamber, and a first portion of the first piston contacts the first rotor arm;
applying pressurized fluid to the first pressure chamber;
urging the first piston partially outward from the first pressure chamber to urge rotation of the rotary output shaft in a first direction;
rotating the rotary output shaft in a second direction opposite that of the first direction; and,
urging the first piston partially into the first pressure chamber to urge pressurized fluid out the first fluid port.

### Claim 20 (depends on 19)

The method of claim 19, wherein the first housing further defines a second arcuate chamber comprising a second cavity, and a second fluid port in fluid communication with the second cavity;
the rotor assembly further comprises a second rotor arm;
the rotary actuator further comprising an arcuate-shaped second piston disposed in said first housing for reciprocal movement in the second arcuate chamber, wherein a second seal, the second cavity, and the second piston define a second pressure chamber, and a first portion of the second piston contacts the second rotor arm.

### Claim 21 (depends on 20)

The method of claim 20, wherein the second piston is oriented in the same rotational direction as the first piston.

### Claim 22 (depends on 20)

The method of claim 20, wherein the second piston is oriented in the opposite rotational direction as the first piston.

### Claim 23 (depends on 19)

The method of claim 19, wherein the rotary actuator further comprises a second housing disposed about the first housing and having a second fluid port, wherein the first housing, the second housing, the seal, and the first piston define a second pressure chamber.

### Claim 24 (depends on 22)

The method of claim 22, wherein rotating the rotary output shaft in a second direction opposite that of the first direction comprises:
applying pressurized fluid to the second pressure chamber; and
urging the second piston partially outward from the second pressure chamber to urge rotation of the rotary output shaft in a second direction opposite from the first direction.

### Claim 25 (depends on 23)

The method of claim 23, wherein rotating the rotary output shaft in a second direction opposite that of the first direction comprises:
applying pressurized fluid to the second pressure chamber; and
urging the first piston partially into the first pressure chamber to urge rotation of the rotary output shaft in a second direction opposite from the first direction.

### Claim 26 (depends on 19)

The method of claim 19, wherein urging the first piston partially outward from the first pressure chamber to urge rotation of the rotary output shaft in a first direction further comprises rotating the output shaft in the first direction with substantially constant torque over stroke.

### Claim 27 (depends on 19)

The method of claim 19, wherein the first seal is disposed about an interior surface of the open end.

### Claim 28 (depends on 20)

The method of claim 20, wherein the second seal is disposed about the periphery of the first piston.

### Claim 29 (depends on 19)

The method of claim 19, wherein the first housing is formed as a one-piece housing.

### Claim 30 (depends on 19)

The method of claim 19, wherein the first seal is formed as a one-piece seal.

### Claim 31 (depends on 19)

The method of claim 19, wherein the first piston is solid in cross-section.

### Claim 32 (depends on 19)

The method of claim 19, wherein the first piston is at least partly hollow in cross-section.

### Claim 33 (depends on 19)

The method of claim 19, wherein the first piston has one of a square, rectangular, ovoid, elliptical, or circular shape in cross-section.