Hydraulic actuator equipped with an end-of travel slowing device

Patent metadata

Field	Value
Publication number	US-11268549-B2
Application number	US-202016872857-A
Country	US
Kind code	B2
Filing date	May 12, 2020
Priority date	May 13, 2019
Publication date	Mar 8, 2022
Grant date	Mar 8, 2022

Abstract

The invention relates to a hydraulic actuator comprising a cylinder (1) in which a piston (2) secured to a rod (4) is mounted so as to slide in a sealed manner in order to delimit in the cylinder a hydraulic extension chamber (5) and a hydraulic retraction chamber (6) that are connected to respective ports, the hydraulic actuator comprising means for slowing the piston when the piston approaches a retracted position. According to the invention, the slowing means comprise first and second hydraulic lines (7, 8) extending between the extension port and the extension chamber, the first hydraulic line comprising a seat (13) while the piston bears a retractable finger (10) having an end (14) that comes to bear against the seat in order to close the first hydraulic line (7) when the piston approaches the retracted position, such that only the second hydraulic line (8) remains open while the piston completes its travel towards the retracted position.Landing gear and aircraft comprising such an actuator.

First claim

The invention claimed is:

1. A hydraulic actuator comprising:
a cylinder in which a piston secured to a rod is mounted so as to slide in a sealed manner in order to delimit in the cylinder a hydraulic extension chamber and a hydraulic retraction chamber that are connected to respective extension and retraction ports, the hydraulic actuator comprising slowing means for slowing the piston when the piston approaches a retracted position,
wherein the slowing means comprise first and second hydraulic passages connecting the extension port and the extension chamber, the first hydraulic passage comprising a seat while the piston bears a retractable finger having an end that comes to bear against the seat in order to close the first hydraulic passage when the piston approaches the retracted position, such that only the second hydraulic passage remains open while the piston completes its travel towards the retracted position, and
wherein the seat is preceded by an internal shape of a ferrule intended to cooperate with the end of the retractable finger before the retractable finger comes to bear against the seat in order to gradually reduce a flow cross section of the first hydraulic passage.

2. The hydraulic actuator according to claim 1 , wherein the seat and the ferrule are in one piece.

3. The hydraulic actuator according to claim 1 , wherein the internal shape of the ferrule is designed to also guide the retractable finger.

4. The hydraulic actuator according to claim 1 , wherein the first and second hydraulic passages extend in an end wall of the cylinder.

5. The hydraulic actuator according to claim 4 , wherein the seat is attached to the end wall of the cylinder.

6. The hydraulic actuator according to claim 1 , wherein the retractable finger is mounted on the piston so as to slide along a central axis of the cylinder.

7. The hydraulic actuator according to claim 1 , wherein the end of the retractable finger is conical.

8. The hydraulic actuator according to claim 1 , wherein the retractable finger is retractable counter to the action of return means that push the retractable finger towards a position protruding from the piston.

9. A landing gear comprising an actuator for manoeuvring the landing gear between an up position and a down position, wherein the actuator comprises the hydraulic actuator according to claim 1 .

10. An aircraft comprising landing gear according to claim 9 .

11. The hydraulic actuator according to claim 1 , wherein the internal shape of the ferrule is a conical internal shape having a circular cross section that decreases towards the seat along a gradual slope.

12. The hydraulic actuator according to claim 1 , wherein the conical internal shape extends to the seat.

Assignees

• Safran Landing Systems

Inventors

• Kamis Jean-Baptiste
• Roger Jean-Charles

Classifications

• F15B15/227 Primary

  having an auxiliary cushioning piston within the main piston or the cylinder end face · CPC title

• F15B15/22

  for accelerating or decelerating the stroke · CPC title

• B64C25/02 Primary

  Undercarriages · CPC title

• F01B11/02

  Equalising or cushioning devices · CPC title

• F15B15/223 Primary

  having a piston with a piston extension or piston recess which completely seals the main fluid outlet as the piston approaches its end position · CPC title