# US 2014/0151501 A1 · Electro hydrostatic actuator system for retracting/extending landing gear

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- Number: US 2014/0151501 A1
- Document ID: US20140151501A1
- Status: Published application
- Kind: A1
- Application number: 14/088,045
- Filed: 2013-11-22
- Published: 2014-06-05
- Earliest claimed: 2012-12-04
- Assignees: Sumitomo Precision Products Co., Ltd.
- Applicants: Sumitomo Precision Products Co., Ltd.
- Inventors: Taku KONDO; Shogo HAGIHARA
- Web page: https://patentgrep.com/patent/US20140151501A1

## CPC

- B64C 25/22: fluid
- B64C 13/504: {using electro-hydrostatic actuators [EHA's]}
- B64C 13/505: {having duplication or stand-by provisions}
- B64C 25/24: electric
- F15B 20/004: {Fluid pressure supply failure}
- F15B 2211/20515: Electric motor
- F15B 2211/20538: constant capacity
- F15B 2211/20576: with multiple pumps
- F15B 2211/6651: Control of the prime mover, e.g. control of the output torque or rotational speed
- F15B 2211/6654: Flow rate control
- F15B 2211/7114: with direct connection between the chambers of different actuators
- F15B 2211/75: Control of speed of the output member
- F15B 2211/783: Sequential control
- F15B 2211/8633: Pressure source supply failure
- F15B 2211/8752: Emergency operation mode, e.g. fail-safe operation mode
- Y02T 50/40: Weight reduction
- B64C: AEROPLANES; HELICOPTERS
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

An electro hydrostatic actuator system for retracting/extending a landing gear includes a plurality of hydraulic actuators and a plurality of hydraulic supply sources each including a single hydraulic pump and a single electric motor and provided in parallel to each other. In a normal state, the hydraulic supply sources together supply operation oil sequentially to the hydraulic actuators. When any of the hydraulic supply sources is failed, the other hydraulic supply source(s) other than the failed hydraulic supply source supplies operation oil sequentially to the hydraulic actuators.

## Claims

### Claim 1

An electro hydrostatic actuator system for retracting/extending a landing gear of an aircraft, comprising:
a plurality of hydraulic actuators configured to sequentially receive, for operation thereof, a supply of operation oil in retraction or extension of the landing gear; and
a plurality of hydraulic supply sources provided in parallel to each other such that the operation oil is supplied to each hydraulic actuator,
wherein each hydraulic supply source includes
a single hydraulic pump configured to discharge the operation oil, and
a single electric motor configured to drive the hydraulic pump,
the hydraulic supply sources together supply the operation oil sequentially to the hydraulic actuators in a normal state of the hydraulic supply sources, and
when at least one of the hydraulic supply sources is failed, at least one hydraulic supply source other than the failed one of the hydraulic supply sources supplies the operation oil sequentially to the hydraulic actuators.

### Claim 2 (depends on 1)

The electro hydrostatic actuator system of claim 1, wherein
the hydraulic actuators are different from each other in operation oil supply conditions required for the operation of the hydraulic actuators, and an operation oil supply capacity of each hydraulic supply source required for sequentially operating the hydraulic actuators to retract or extend the landing gear is set based on the supply conditions,
a supply capacity of each hydraulic supply source is set so as to be lower than the required supply capacity of each hydraulic supply source,
in the normal state of the hydraulic supply sources, the hydraulic pump of each hydraulic supply source is driven at a predetermined rotational speed to supply the operation oil sequentially to the hydraulic actuators, and
when at least one of the hydraulic supply sources is failed, the hydraulic pump of at least one hydraulic supply source other than the failed one of the hydraulic supply sources is driven at a rotational speed higher than the predetermined rotational speed.

### Claim 3 (depends on 2)

The electro hydrostatic actuator system of claim 2, wherein
the hydraulic supply sources include first and second hydraulic supply sources, and
the first and second hydraulic supply sources have an identical operation oil supply capacity.

### Claim 4 (depends on 1)

The electro hydrostatic actuator system of claim 1, wherein
the hydraulic supply sources provided in parallel to each other each include a check valve arranged downstream of the hydraulic pump.