BR-102019026001-B1 - Actuator control arrangement and spoiler control arrangement for an aircraft.

Abstract

ACTUATOR CONTROL ARRANGEMENT, AND SPOILER CONTROL ARRANGEMENT FOR AN AIRCRAFT. An actuator control arrangement comprising: a hydraulic actuator (100) having a housing (200) and a piston rod (300) movable axially within the housing between a neutral position, a retracted position and an extended position relative to the housing in response to the application of pressure on the piston rod; a stop (900) disposed within the housing to limit the extent of the movement of the piston rod to the housing, the stop movable between a neutral position and a retracted position; and a solenoid valve (140) disposed between a pressure source and the actuator, the solenoid valve being switchable between a first mode and a second mode in response to an electrical control signal, wherein, in the first mode, the solenoid valve creates a fluid flow path from the pressure source to the actuator so as to locate the stop in its neutral position and in the second mode, the solenoid valve creates a fluid flow path to release the pressure from the actuator to allow the stop to move to its retracted position. In case of electrical failure, the stop will adjust the actuator to its (...).

Inventors

• Raphael Medina

Assignees

• GOODRICH ACTUATION SYSTEMS SAS

Dates

Publication Date

20260317

Application Date

20191209

Priority Date

20190211

Claims (5)

1. 1. Actuator control arrangement, characterized in that it comprises: a hydraulic actuator (100) having a housing (200) and a piston rod (300) movable axially within the housing (200) between a neutral position, a retracted position and an extended position relative to the housing (200) in response to the application of pressure on the piston rod (300); a stop (900) disposed within the housing and extending through an interior of the housing (200), the stop (900) disposed to define a first chamber of the housing (200) on the piston side of the stop (900) and a second chamber of the housing (200) on the other side of the stop (900), to limit the extent of movement of the piston rod (300) to the housing (200), the stop (900) being movable between a neutral position and a retracted position; a solenoid valve (140) disposed between a pressure source and the actuator (100), the solenoid valve (140) being skewed in a first mode when not activated by an electrical control signal and switchable from the first mode to a second mode in response to an electrical control signal, wherein, in the first mode, the solenoid valve (140) creates a fluid flow path from the pressure source to the actuator (100) so as to locate the stop (900) in its neutral position and in the second mode, the solenoid valve (140) creates a fluid flow path to release the pressure from the actuator (100) to allow the stop (900) to move to its retracted position; an electro-hydraulic servo valve, EHSV, (120) between the pressure source and the actuator (100) to control the direction of pressurized fluid to the actuator (100) in response to an electrical control signal; wherein the EHSV (120) is movable between a first position in which high-pressure fluid is directed from the fluid source to a first chamber of the actuator (100) to cause extension of the piston rod (300) and a second position by which high-pressure fluid is directed to a second chamber of the actuator (100) to cause retraction of the piston rod (300) relative to the housing (200); wherein, in a tilt mode, in response to an electrical control signal, the EHSV (120) is in the second position and the solenoid valve (140) is activated in the second mode, thus releasing pressure from the second chamber to allow the stop (900) to retract from the neutral position, and wherein, in the case of Failure of the electrical control signal, the solenoid valve (140) returns to the first mode in which pressure is supplied from the pressure source to the second chamber to cause the stop (900) to return to the neutral position.
2. 2. Actuator control arrangement according to claim 1, characterized in that a standard position of the EHSV (120) is the second position.
3. 3. Actuator control arrangement according to claim 1, characterized in that it further comprises an anti-extension valve (130) provided between the EHSV (120) and the actuator (100) configured to move between a first position in which a fluid path is created between the EHSV (120) and the actuator (100) and a second anti-extension position to prevent extension of the piston rod (300) relative to the housing (200) in the event of loss of pressure.
4. 4. Actuator control arrangement according to claim 1, characterized in that, in the event of failure of the electrical control signal, the stop (900) returns from its retracted position to its neutral position.
5. 5. Spoiler control arrangement for an aircraft comprising an actuator control arrangement as defined in claim 1, characterized in that it further comprises a spoiler movable relative to a wing surface and an actuator (100) arranged to move the spoiler by moving the piston rod (300).

Description

TECHNICAL FIELD [001] This disclosure relates to valve arrangements for controlling a hydraulic actuator, such as for positioning movable surfaces, such as spoilers on aircraft. FUNDAMENTALS [002] Hydraulic actuators have various applications, particularly in controlling the movement of a moving component. In aircraft, many moving components and surfaces are moved by means of a hydraulic actuator. [003] In general terms, a hydraulic actuator comprises a cylindrical housing in which an axially movable piston rod is mounted. A rod head, inside the housing, divides the housing into two chambers, each having a fluid orifice through which pressurized fluid can be injected into the chamber or through which low-pressure fluid exits the chamber, so as to change the relative pressure in the two chambers on either side of the piston head, thereby creating movement of the piston relative to the housing. One end of the piston rod extending out of the housing is fixed to a component or surface to be moved. Hydraulic fluid is supplied to the actuator from a hydraulic fluid feed in fluid communication with the interior of the actuator housing through orifices in the housing to cause the piston rod to extend out of the housing, or fluid is drawn out of the housing to cause the piston rod to retract back into the housing. The movement of the piston rod is determined by the direction and/or pressure of the fluid applied to the actuator, which occurs in response to a control signal. [004] As the piston rod moves relative to the housing, the moving component or surface to which it is attached will move accordingly. [005] In order to allow both rod extension and rod retraction, a valve is provided to define the movement as extension or retraction. This may be a servo valve, more specifically, an electro-hydraulic servo valve (EHSV). The valve is positioned between the hydraulic fluid supply and the actuator and is movable, in response to an electrical control signal, between a first position in which high-pressure fluid flows from the supply into one chamber of the actuator housing and low-pressure fluid exits from the other chamber, and a second position in which high-pressure fluid is injected into the other chamber and extracted from the first chamber of the actuator housing. The valve may also have a neutral or closed position in which the actuator housing is neither supplied with fluid nor is fluid extracted from the actuator housing. [006] A particular application for hydraulic actuators controlled by an EHSV is in controlling the movement of a spoiler. A spoiler is a movable surface on an aircraft wing behind the wing flap. When the aircraft is cruising, both the wing flap and the spoiler lie flat along the wing. To reduce the aircraft's speed, the spoiler is raised upward relative to the wing. [007] The movement of the repressor is caused by a hydraulic actuator that extends as described above. [008] If electrical power is lost when the spoiler is extended, excessive drag may be exerted by the spoiler. Therefore, systems are known to retract the spoiler to its “zero” position in the housing in case of electrical power loss. Generally, this occurs by means of the EHSV which is tilted to a valve position where high-pressure fluid is supplied to the chamber on the piston rod side of the piston head so that the pressure on the head side is greater in the other chamber, causing the piston to retract into the housing. This will be described in more detail below. [009] In a conventional manner, a mechanical stop in the lower part of the housing interrupts the piston rod at the zero position. [0010] Problems can also occur in spoiler control if there is a loss of hydraulic power. In the present context, in order to prevent actuator extension, one solution is an anti-extension valve between the EHSV and the actuator that is switched to a pressure relief position when the hydraulic pressure drops below a predetermined pressure (typically 1.2 times a given “stall” pressure). Again, this will be described in more detail below. [0011] If the spoiler is extended and pressure is lost, the spoiler will be retracted by the aerodynamic load and will gradually fall until it aligns with the wing surface until a zero articulation position is reached. It is important to maintain the spoiler in this position to prevent spurious extension. [0012] Most aircraft have a spoiler that operates using a positive movement of the actuator rod, i.e., to extend the rod in order to raise the spoiler. The actuator stroke is between a “zero” position in the housing and an extended position, and the control system is tilted to return the rod to the zero position. [0013] More recently, some aircraft have incorporated a “tilt” function in the spoiler, using a negative piston rod stroke - that is, returning to the housing beyond the zero position or, put another way, a stroke that moves from the zero position in the opposite direction to the direction moved in