Actuator for an aircraft landing gear assembly

Patent metadata

Field	Value
Publication number	US-11820495-B2
Application number	US-202117319722-A
Country	US
Kind code	B2
Filing date	May 13, 2021
Priority date	Mar 20, 2020
Publication date	Nov 21, 2023
Grant date	Nov 21, 2023

Abstract

A single acting actuator for an aircraft landing gear assembly is disclosed having a piston mounted in a cavity and moveable relative to a housing between a retracted position and an extended position, the piston dividing the cavity into first and second pressure chambers. At least one of the pressure chambers is associated with first and second outlets, with the actuator being arranged such that, in respect of the relative movement in which the pressure chamber is the decreasing volume pressure chamber, in a first stage of the relative movement the first and second outlets are open thereby allowing actuator fluid to flow out of the pressure chamber through the first and second outlets and in a second stage of the relative movement the second outlet is open but the first outlet is closed, thereby acting to slow the relative movement of the piston with respect to the housing.

First claim

The invention claimed is:

1. A single acting actuator for an aircraft landing gear assembly, the actuator comprising:
a housing;
a cavity provided in the housing;
a piston and a piston rod connected to the piston;
the piston being mounted in the cavity for relative movement with respect to the housing such that the piston and piston rod are movable relative to the housing between a retracted position and an extended position;
the piston dividing the cavity into first and second pressure chambers such that the volume of one of the pressure chambers is increased and the volume of the other is decreased as the piston is moved relative to the housing;
the piston being movable relative to the housing from one of the retracted and extended positions to the other by a resultant force on the piston due to the pressure of actuator fluid in the first and second pressure chambers;
wherein at least one of the pressure chambers is associated with first and second outlets, with the actuator being arranged such that, in respect of the relative movement in which the pressure chamber is the decreasing volume pressure chamber,
in a first stage of the relative movement the first and second outlets are open thereby allowing actuator fluid to flow out of the pressure chamber through the first and second outlets the flow through the second outlet being restricted relative to the flow through the first outlet,
and in a second stage of the relative movement the second outlet is open but the first outlet is closed, thereby acting to slow the relative movement of the piston with respect to the housing.

2. An actuator according to claim 1 wherein the first and second pressure chambers are connected such that actuator fluid flows from the decreasing volume pressure chamber to the increasing volume pressure chamber.

3. An actuator according to claim 1 wherein both the first and second pressure chambers are associated with respective said first and second outlets.

4. An actuator according to claim 1 wherein the first and/or second outlets associated with the, or each, pressure chamber is also an inlet for actuator fluid.

5. An actuator according to claim 1 wherein, in respect of the or each pressure chamber, the first and second outlets are provided in the housing, with the second outlet positioned outboard of the first outlet such that in the second stage of relative movement the piston closes the first outlet but not the second outlet.

6. An actuator according to claim 5 , wherein the actuator comprises an external connection that connects the first and/or second outlets associated with the second pressure chamber to the first and/or second outlets associated with the first pressure chamber.

7. An actuator according to claim 1 wherein, in respect of the or each pressure chamber, one of the first or second outlets is provided in the piston rod and the other is provided in the piston such that during the second stage of relative movement the first outlet is closed by a part of the actuator.

8. An actuator according to claim 7 , wherein both the first and second pressure chambers are associated with respective said first and second outlets, the outlets in the piston rod are connected by a first flow path and the outlets in the piston are connected by a second flow path such that there is a connection between the first and second pressure chambers that comprises the first and second flow paths.

9. An actuator according to claim 1 , wherein there is a connection, comprising an internal flow path, between the first and second pressure chambers.

10. An actuator according to claim 9 wherein the connection passes across the piston.

11. An actuator according to claim 9 , wherein the connection passes through the piston and/or piston rod.

12. An actuator according to claim 1 , wherein the rear side of the piston, in relation to the direction of movement of the piston relative to the housing due to the pressure of actuator fluid in the first and second pressure chambers, has a greater exposed cross-sectional area than the front side of the piston.

13. An aircraft landing gear system comprising:
an aircraft landing gear assembly; and
an actuation system comprising the actuator according to claim 1 ; an actuator fluid reservoir; and a pump; arranged such that the pump is operable to pump actuator fluid from the reservoir to the actuator so as to pressurise actuator fluid in at least one of the first and second pressure chambers so as to move the piston relative to the housing from the one of the retracted and extended positions to the other;
wherein the actuator is arranged such that the movement of the piston relative to the housing from the one of the retracted and extended positions to the other, by a resultant force on the piston due to the pressure of actuator fluid in the first and second pressure chambers, actuates the landing gear assembly from a first configuration to a second configuration;
the landing gear assembly is movable from the second configuration to the first configuration under the action of a force on the landing gear assembly;
and the actuator is arranged such that the movement of the landing gear assembly from the second configuration to the first configuration, under the action of said force, acts to move the piston relative to the housing from the other of the retracted and extended positions to said one of the retracted and extended positions.

14. An aircraft landing gear system according to claim 13 wherein the force on the landing gear assembly comprises the weight of at least one component of the landing gear assembly and/or aerodynamic force on the landing gear assembly.

15. An aircraft landing gear system according to claim 13 wherein the landing gear assembly comprises landing gear and/or a landing gear door.

16. An aircraft landing gear system according to claim 13 , wherein:
the actuator is a first actuator and the actuation system comprises a second actuator;
the landing gear system comprises a lock that is movable between a locked configuration and an unlocked configuration so as to lock and unlock the landing gear assembly in the second configuration;
and the second actuator is arranged to actuate the lock between its locked configuration and its unlocked configuration.

17. An aircraft comprising an aircraft landing gear system according to claim 13 .

18. A method of actuation of an aircraft landing gear assembly using a single acting actuator according to claim 1 ,
wherein the method comprises:
a) moving the piston relative to the housing from the one of the retracted and extended positions to the other, under the action of a resultant force on the piston due to the pressure of actuator fluid in the first and second pressure chambers, so as to move the landing gear assembly from a first configuration to a second configuration; and
b) moving the landing gear assembly from the second configuration to the first configuration under the action of a force on the landing gear assembly, thereby acting to move the piston relative to the housing from the other of the retracted and extended positions to said one of the retracted and extended positions.

19. A single acting actuator for an aircraft landing gear assembly, comprising:
a housing;
a cavity provided in the housing;
a piston and a piston rod connected to the piston;
the piston being mounted in the cavity for relative movement with respect to the housing such that the piston and piston rod are movable relative to the housing between a retracted position and an e

Assignees

• Airbus Operations Ltd

Inventors

• Kerr Sean
• Marles David
• L'Allier Paul Gordon

Classifications

• B64C25/22 Primary

  fluid · CPC title

• B64C25/30

  emergency actuated · CPC title

• F15B15/224

  having a piston which closes off fluid outlets in the cylinder bore by its own movement · CPC title

• F15B15/14 Primary

  of the straight-cylinder type · CPC title

• F15B2211/7052

  Single-acting output members · CPC title