Hydraulic circuit for operating an aircraft landing gear

Patent metadata

Field	Value
Publication number	US-10851815-B2
Application number	US-201916691065-A
Country	US
Kind code	B2
Filing date	Nov 21, 2019
Priority date	Nov 23, 2018
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

The invention relates to a hydraulic circuit for operating an aircraft landing gear comprising:
a general valve ( 1 ) for admitting a supply pressure into the circuit; distributors ( 4, 6 ) for supplying undercarriages and/or landing gear doors operating actuators ( 3 ) or release actuators for hooks ( 5 ) maintaining the undercarriages and/or the doors in the retracted position; a depressurization valve ( 102 ) for, in an open position, allowing the selective distribution of supply pressure to an extension chamber ( 3 A) or a retraction chamber ( 3 B) of each operating actuator by the distributors, and, in a depressurization position, forcing the return of a retraction chamber of each operating cylinder.

According to the invention, the depressurization valve is returned ( 105 ) in a stable manner to the depressurization position, and is moved into the open position only in response to the presence of supply pressure downstream of the general valve.

First claim

The invention claimed is:

1. A hydraulic circuit for operating an aircraft landing gear comprising:
a general valve ( 1 ) for admitting a supply pressure into the circuit;
distributors ( 4 , 6 ) for supplying undercarriages and/or landing gear doors operating actuators ( 3 ) or release actuators for hooks ( 5 ) maintaining the undercarriages and/or the doors in the retracted position;
a depressurization valve ( 102 ; 202 ) for, in an open position, allowing the selective distribution of supply pressure to an extension chamber ( 3 A) or a retraction chamber ( 3 B) of each actuator by the distributors, and, in a depressurization position, forcing the return of a retraction chamber of each operating actuator;

characterized in that the depressurization valve is returned ( 105 ; 205 ) in a stable manner to the depressurization position, and is moved into the open position only in response to the presence of supply pressure downstream of the general valve.

2. A hydraulic circuit according to claim 1 , wherein a bypass ( 104 ; 204 ) extends from a supply line (LA) extending between the general valve ( 1 ) and the valves ( 4 , 6 ) to supply a pressure control ( 103 ; 203 ) of the depressurization valve placing it in the open position against a return spring ( 105 ; 205 ) to the depressurization position.

3. The hydraulic circuit according to claim 1 , wherein the depressurization valve ( 102 ) is located between the general valve ( 1 ) and the distributors ( 4 , 6 ).

4. The hydraulic circuit according to claim 1 , wherein the depressurization valve ( 202 ) is placed on a hydraulic line extending between the distributors ( 4 , 6 ) and the retraction chambers of the actuating actuators.

Assignees

• Safran Landing Systems

Inventors

• Frank David
• Belleval Jean-Luc

Classifications

• B64C25/30 Primary

  emergency actuated · CPC title

• B64C25/22 Primary

  fluid · CPC title

• F15B20/004 Primary

  Fluid pressure supply failure · CPC title

• B64C25/26

  Control or locking systems therefor · CPC title

• F15B2211/30595

  with additional valves between the groups of valves for multiple output members · CPC title