Servo-control and an aircraft having such a servo-control

Patent metadata

Field	Value
Publication number	US-9732769-B2
Application number	US-201614989105-A
Country	US
Kind code	B2
Filing date	Jan 6, 2016
Priority date	Jan 6, 2015
Publication date	Aug 15, 2017
Grant date	Aug 15, 2017

Abstract

A servo-control having at least one movable cylinder that includes a hydraulic directional control valve. The hydraulic valve includes a control shaft that is rotatable about a longitudinal axis, the control shaft being connected to a distributor slide. The servo-control including a stationary abutment member secured to a cylinder and an input lever situated outside the cylinder. The input lever is connected to the control shaft and includes a stop portion arranged in the abutment member. The servo-control includes movement means for moving the input lever longitudinally, a first abutment surface of the abutment member limiting a travel amplitude of the stop portion when the input lever is in a first position.

First claim

What is claimed is:

1. A servo-control having at least one movable cylinder and a stationary power rod, the power rod having one piston per cylinder, each piston defining a chamber referred to as a “retraction” chamber and a chamber referred to as an “extension” chamber in a casing of the cylinder,
each cylinder including a hydraulic directional control valve provided with at least one hydraulic inlet suitable for being connected to a fluid delivery system and at least one hydraulic outlet suitable for being connected to a fluid discharge system,
each hydraulic valve of a cylinder comprising at least one hydraulic distributor slide movable within the hydraulic valve in order to put each chamber of the cylinder on request into fluid flow communication with the hydraulic inlet or the hydraulic outlet,
the hydraulic valve having a control shaft that is rotatable about a longitudinal axis, the servo-control including an input lever situated outside each cylinder,
the input lever being suitable for being connected to a linkage for generating a movement order for the servo-control,
wherein the control shaft is connected to the distributor slide so that a rotary turn of the control shaft causes the distributor slide to move,
the input lever being connected to the control shaft and being movable with a first movement to cause the control shaft to turn,
the servo-control including a stationary abutment member secured to at least one of the cylinders,
the abutment member having at least a first abutment surface, the input lever including a stop portion co-operating with the abutment member,
the servo-control including movement means for moving the input lever in a second movement in longitudinal translation from a first position to a second position and vice versa as a function of a predetermined condition,
the first abutment surface limiting press-free travel of the stop portion during a first movement to a first amplitude solely when the input lever is in the first position.

2. A servo-control according to claim 1 , wherein the abutment member includes a second abutment surface distinct from the first abutment surface, the second abutment surface limiting the travel amplitude of the stop portion during the first movement to a second amplitude when the input lever is in the second position, the second amplitude being different from the first amplitude.

3. A servo-control according to claim 1 , wherein the abutment member includes an abutment surface that varies longitudinally from the first abutment surface.

4. A servo-control according to claim 1 , wherein the stop portion is centered within the first abutment surface when the servo-control is supplied with hydraulic fluid at a pressure greater than a “minimum” pressure threshold, the distributor slide hydraulically isolating the chambers from the hydraulic inlet and the hydraulic outlet.

5. A servo-control according to claim 1 , wherein the movement means include an actuator connected to the input lever and a control device suitable for giving an order to the actuator to move the input lever in longitudinal translation.

6. A servo-control according to claim 1 , wherein the movement means include a cavity, the movement means moving the input lever in longitudinal translation from a first position to a second position, and vice versa, as a function of a threshold referred to as “maximum” threshold for a pressure in the cavity.

7. A servo-control according to claim 6 , wherein the servo-control includes a hydraulic circuit delivering hydraulic fluid to a hydraulic inlet of a cylinder, the cavity being arranged in the hydraulic circuit.

8. A servo-control according to claim 6 , wherein the cavity is arranged in the control shaft within the cylinder, the control shaft being constrained to move in longitudinal translation with the input lever, the movement means including a fluid-flow connection connecting the cavity with the hydraulic inlet.

9. A servo-control according to claim 8 , wherein the hydraulic valve includes a resilient member that keeps the control shaft in the first position below the maximum pressure threshold.

10. A servo-control according to claim 1 , wherein the control shaft includes a longitudinally extending elongate structure and an elongate arm secured to the elongate structure, the elongate arm extending longitudinally in parallel with the elongate structure, the elongate arm sliding in an orifice in the distributor slide.

11. A servo-control according to claim 1 , wherein the control shaft projects in part from the cylinder, having a non-projecting portion arranged in the cylinder and a projecting portion arranged outside the cylinder, the non-projecting portion being mechanically connected to the distributor slide, the projecting portion being mechanically connected to the input lever.

12. A servo-control according to claim 1 , wherein the abutment member includes a clevis having a first cheek and a second cheek, at least one cheek having at least one first arcuate abutment surface, a space between the cheeks being suitable for having a control link of the linkage passing therethrough.

13. A servo-control according to claim 12 , wherein at least one cheek includes at least one second arcuate abutment surface.

14. A servo-control according to claim 1 , wherein the input lever is secured to the control shaft.

15. A servo-control according to claim 1 , wherein the input lever is hinged to the control shaft.

16. A servo-control according to claim 1 , wherein the stop portion includes a hinge suitable for being connected to the linkage.

17. An aircraft, including at least one servo-control according to claim 1 .

Assignees

• Airbus Helicopters

Inventors

• Bihel Jean-Romain
• Marger Thibaut
• Pujol Christophe
• Pantaine Alexandre

Classifications

• B64C27/12

  Rotor drives · CPC title

• F15B2211/8752

  Emergency operation mode, e.g. fail-safe operation mode · CPC title

• F15B11/10 Primary

  in which the servomotor position is a function of the pressure {also pressure regulators as operating means for such systems, the device itself may be a position indicating system} · CPC title

• F15B18/00

  Parallel arrangements of independent servomotor systems · CPC title

• F15B9/10 Primary

  in which the controlling element and the servomotor each controls a separate member, these members influencing different fluid passages or the same passage · CPC title