Ram air turbine stowing system

Patent metadata

Field	Value
Publication number	US-2016288919-A1
Application number	US-201514677194-A
Country	US
Kind code	A1
Filing date	Apr 2, 2015
Priority date	Apr 2, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A ram air turbine (RAT) stowing system includes a closed loop hydraulic circuit configured to hold a quantity of a hydraulic fluid to be utilized only by the RAT stowing system and a RAT actuator disposed in fluid communication with the closed loop hydraulic circuit. A pump system is connected to the hydraulic circuit to selectively pump the hydraulic fluid to a stow reservoir portion of the RAT actuator to move the RAT actuator from a deployed position to a stowed position. A control valve is connected to the hydraulic circuit between the RAT actuator and the pump to selectively allow the hydraulic fluid to be drained from the stow reservoir portion of the RAT actuator in a drain state and to allow the hydraulic fluid to be pumped into the stow reservoir portion of the RAT actuator in a pump state.

First claim

What is claimed is:

1 . A ram air turbine (RAT) stowing system, comprising:
a closed loop hydraulic circuit configured to hold a quantity of a hydraulic fluid to be utilized only by the RAT stowing system; a RAT actuator disposed in fluid communication with the closed loop hydraulic circuit; a pump system connected to the hydraulic circuit to selectively pump the hydraulic fluid to a stow reservoir portion of the RAT actuator to move the RAT actuator from a deployed position to a stowed position; and a control valve connected to the hydraulic circuit between the RAT actuator and the pump to selectively allow the hydraulic fluid to be drained from the stow reservoir portion of the RAT actuator in a drain state and to allow the hydraulic fluid to be pumped into the stow reservoir portion of the RAT actuator in a pump state.

2 . The system of claim 1 , wherein the hydraulic fluid is drained from the stow reservoir portion of the RAT actuator through the closed loop hydraulic circuit to a deploy reservoir portion of the RAT actuator.

3 . The system of claim 1 , the closed loop hydraulic circuit includes an accumulator disposed therein for accumulating a predetermined quantity of the hydraulic fluid when the valve is in the drain state.

4 . The system of claim 1 , wherein the closed loop hydraulic circuit includes a pressure relief valve for preventing over pressurization by the pump system.

5 . The system of claim 1 , wherein the control valve includes a pressure actuated valve, wherein the control valve is biased to the drain state, such that a predetermined pressure from the pump system causes the control valve to change from the drain state to the pump state.

6 . The system of claim 5 , wherein a rate control orifice is disposed between the control valve and the pump system for controlling a rate of pressure build up and/or relief on the control valve to control the rate of state change.

7 . The system of claim 1 , wherein the pump system includes a pump and a motor.

8 . The system of claim 7 , wherein the motor is operatively connected to an electrical source.

9 . The system of claim 8 , wherein the electrical source is an aircraft battery.

10 . The system of claim 8 , wherein the electrical source is ground power.

11 . The system of claim 8 , wherein the electrical source is a RAT battery.

12 . The system of claim 1 , wherein the RAT actuator is operatively associated with a locking mechanism to lock the RAT in the stowed position such that the pump system can turn off after locking the RAT actuator in the stowed position so as to relieve hydraulic pressure from the RAT actuator in order to allow the RAT to be freely redeployed.

13 . The system of claim 12 , wherein the RAT actuator is biased to move to the deployed position when the locking mechanism is released.

14 . The system of claim 13 , wherein the RAT actuator is biased with a spring.

15 . A method, comprising:
stowing a ram air turbine (RAT) using a RAT stowing system, the RAT stowing system including:
a closed loop hydraulic circuit configured to hold a quantity of a hydraulic fluid to be utilized only by the RAT stowing system;
a RAT actuator disposed in fluid communication with the closed loop hydraulic circuit;
a pump system connected to the hydraulic circuit to selectively pump the hydraulic fluid to a stow reservoir portion of the RAT actuator to move the RAT actuator from a deployed position to a stowed position; and
a control valve connected to the hydraulic circuit between the RAT actuator and the pump to selectively allow the hydraulic fluid to be drained from the stow reservoir portion of the RAT actuator in a drain state and to allow the hydraulic fluid to be pumped into the stow reservoir portion of the RAT actuator in a pump state.

Assignees

• Hamilton Sundstrand Corp

Inventors

• Sasscer Gary
• Kandil Magdy A

Classifications

• B64D41/007 Primary

  Ram air turbines · CPC title

• F15B15/14

  of the straight-cylinder type · CPC title

• Y02T50/40

  Weight reduction · CPC title