Dual-mode hydraulic servo actuator

Abstract

The present invention relates to a dual-mode hydraulic servo actuator, comprising: an oil inlet line and an oil return line, wherein the oil inlet line is branched to a servo valve and a first-stage mode selection valve, and the oil return line is connected to a variable damping valve; a second-stage mode selection valve connected to the first-stage mode selection valve, the servo valve, and the variable damping valve; and an actuator connected to the second-stage mode selection valve, which performs linear output when the hydraulic servo actuator is in a first mode. The hydraulic servo actuator also includes a pressure relief unit, wherein when the hydraulic servo actuator is in a second mode, the actuator is connected to the variable damping valve / pressure relief unit, and the pressure relief unit provides a maintenance interface and a release function for releasing the damping force, so that there is no damping conduction between the actuator and the oil return line. The above-mentioned hydraulic servo actuator solves the problem of operational difficulties caused by the damping force during ground maintenance, significantly improves the operability and convenience of maintenance inspections, and improves the economy of aircraft operations.

Description

Technical Field

[0001] The present invention relates to a dual-mode hydraulic servo actuator, and more particularly to a dual-mode hydraulic servo actuator with a pressure relief function. Background Art

[0002] Based on system functionality and safety requirements, the primary control surfaces of civil aircraft primary flight control systems typically utilize hydraulic servo actuators in both active and damping modes as their actuators. When the aircraft is powered and pressurized normally, the hydraulic servo actuator operates in active mode; when pressure or power is removed, the hydraulic servo actuator enters damping mode and provides damping force. This damping mode design provides both in-flight flutter suppression and ground gust protection, ensuring functional and structural integrity.

[0003] Figure 1 The diagram shows the operating principle of a conventional active-damping dual-mode hydraulic servo actuator. The conventional hydraulic servo actuator has an oil inlet line starting at an oil inlet connector 1 and an oil return line ending at an oil return connector 2. The oil inlet line passes through an oil inlet filter 3 and is diverted via an oil inlet check valve 5 to a servo valve 6 and a first-stage mode selector valve 7. The oil return line connects to a variable damping valve 9 via a return oil backpressure valve 4. The servo valve 6 is a three-position, four-way valve, while the first-stage mode selector valve 7 and the variable damping valve 9 are both two-position, three-way valves.

[0004] The hydraulic servo actuator also features a second-stage mode selector valve 8, connected to the first-stage mode selector valve 7, the servo valve 6, and the variable damping valve 9, and an actuator 10 connected to the second-stage mode selector valve 8. The second-stage mode selector valve 8 is a two-position, six-way valve. When the hydraulic servo actuator is in active operation, the first-stage mode selector valve 7 is energized and connected to a relatively high-pressure oil inlet line via a control port, pushing the second-stage mode selector valve 8 to its first position 8X. In this position, the first and third control ports 6X and 6Z of the servo valve 6 are connected to the two chambers 10X and 10Y of the actuator 10 via the second-stage mode selector valve 8, controlling the reciprocating movement of the piston rod of the actuator 10 and producing linear output.

[0005] When the hydraulic servo actuator is in the damping mode, the first-stage mode selector valve 7 is deenergized and / or hydraulically deenergized, and the second-stage mode selector valve 8 reaches the second state position 8Y, connecting the two chambers 10X and 10Y of the actuator cylinder 10 to the variable damping valve 9 via the second-stage mode selector valve 8. At this point, the hydraulic servo actuator does not actively output force, but is capable of providing damping force.

[0006] However, when the aircraft is electrically depressed on the ground, the hydraulic servo actuator is still in the damping working mode, so maintenance personnel need to apply a large force to push the control surface to carry out related installation / removal and maintenance inspection work, resulting in unsatisfactory maintainability and economy.

[0007] To this end, those skilled in the art have proposed a variety of technical solutions in an attempt to solve the above technical problems.

[0008] In the Chinese patent application CN111498087A entitled “An Electro-Hydraulic Servo Actuator” filed by Qingan Group Co., Ltd. on April 30, 2020, an electro-hydraulic servo actuator is disclosed. Based on the existing servo actuator, the electro-hydraulic servo actuator adds a mode conversion component and a system backpressure component to achieve multi-mode control conversion, thereby meeting the safety requirements based on the aircraft control surface actuation architecture. However, although the electro-hydraulic servo actuator disclosed in this prior art is also a hydraulic servo actuator with an active-damping dual working mode, it does not have a pressure relief function, but is merely an improved design of the mode selection component and the backpressure component to meet the safety requirements of the aircraft. Therefore, it cannot solve the technical problems mentioned in this application.

[0009] Chinese patent application CN111516858A, titled "An Electro-Hydraulic Servo Actuator," also filed by Qing'an Group Co., Ltd. on April 30, 2020, discloses an electro-hydraulic servo actuator. This electro-hydraulic servo actuator, based on the aforementioned prior art, incorporates improvements to the motor-pump assembly to achieve multi-modal control conversion. Similar to the aforementioned prior art, this improved electro-hydraulic servo actuator still lacks a pressure relief function and similarly fails to address the technical issues addressed in this application.

[0010] In U.S. patent application US2016096617A1, entitled "Hydraulic Actuator," filed by NABTESCO Inc. on October 1, 2015, a hydraulic actuator is disclosed, suitable for actuating wing spoilers with flaps. When the hydraulic actuator actuates the spoiler in the overlapping region between the flap and spoiler actuation ranges, an output suppression structure suppresses the hydraulic actuator's drive output in the overlapping region to a value lower than the drive output in the non-overlapping region excluding the overlapping region. Furthermore, the right passage chamber of the hydraulic valve provides a manual pressure relief function by connecting the actuator piston chamber and the oil return line via a spring mechanism. However, this prior art spoiler actuator is not a hydraulic actuator with both active and damping operation modes. In fact, it lacks a damping mode, and its architectural foundation is completely different from that of traditional active and damping hydraulic actuators.

[0011] To this end, it is necessary to design a hydraulic servo actuator that can easily and simply release the damping force when the hydraulic servo actuator is in the damping mode. Summary of the Invention

[0012] An object of the present invention is to provide a dual-mode hydraulic servo actuator with a pressure release function, which can easily and simply release the damping force when the actuator is in a damping mode.

[0013] The present invention discloses a dual-mode hydraulic servo actuator, comprising: an oil inlet pipeline with an oil inlet joint as a starting point, the oil inlet pipeline being branched to a servo valve and a first-stage mode selection valve; an oil return pipeline with an oil return joint as a node, the return pipeline being connected to a variable damping valve; a second-stage mode selection valve, the second-stage mode selection valve being connected to the first-stage mode selection valve, the servo valve and the variable damping valve; and an actuator cylinder connected to the second-stage mode selection valve, when the hydraulic servo actuator is in the first mode, the actuator cylinder performs linear output, wherein the hydraulic servo actuator also includes a pressure relief unit, when the hydraulic servo actuator is in the second mode, the actuator cylinder is connected to the variable damping valve / pressure relief unit, the pressure relief unit providing a maintenance interface and a release function of releasing the damping force, so that there is no damping conduction between the actuator cylinder and the return oil pipeline.

[0014] In the above technical solution, the term "pressure relief unit" is not limited to a certain functional component. If multiple components can release the damping force when combined with each other, these components should also be included in the category of "pressure relief unit".

[0015] In a preferred embodiment, the pressure relief unit may be composed of a variable damping valve in the form of a three-position three-way valve, which is controlled by hydraulic pressure and mechanical spring force.

[0016] Specifically, when there is a pressure difference between the first chamber and the second chamber of the actuator, the variable damping valve enters the first state position, connecting and balancing the pressures of the first chamber and the second chamber of the actuator.

[0017] When the variable damping valve is in the second state, the first chamber and the second chamber of the actuator are connected to the return oil pipeline with damping, and when the variable damping valve is in the third state, undamped conduction is achieved between the actuator and the return oil pipeline, and between the first chamber and the second chamber of the actuator.

[0018] In another preferred embodiment, the pressure relief unit may be composed of a first pressure relief valve and a second pressure relief valve disposed between the first chamber and the second chamber of the actuator and the secondary mode selection valve.

[0019] In another preferred embodiment, the pressure relief unit may be composed of a first pressure relief valve and a second pressure relief valve disposed between the secondary mode selection valve and the variable damping valve.

[0020] According to the records of this application, the hydraulic servo actuator may also include:

[0021] An oil inlet filter and an oil inlet check valve, wherein the oil inlet pipeline passes through the oil inlet filter and is diverted to the servo valve and the first-stage mode selection valve via the oil inlet check valve; and

[0022] The return oil back pressure valve is connected to the variable damping valve via the return oil back pressure valve.

[0023] Preferably, the servo valve may be a three-position four-way valve, and more preferably controlled by both electric current and hydraulic pressure.

[0024] Preferably, the first-stage mode selection valve may be a two-position three-way valve, and more preferably controlled by electromagnetic control.

[0025] Preferably, the second-stage mode selection valve may be a two-position six-way valve, and more preferably controlled by a hydraulic pilot.

[0026] The dual-mode hydraulic servo actuator with pressure relief function according to the present invention can achieve the following advantages:

[0027] (1) The dual-mode hydraulic servo actuator with a pressure relief function according to the present invention effectively solves the problem of operational difficulties caused by the damping force during ground maintenance after the flight control actuator is electrically depressed, significantly improves the operability and convenience of aircraft maintenance inspections, and thus improves the economy of aircraft operations.

[0028] (2) The present invention designs the unit with the pressure relief function to be integrated with the hydraulic servo actuator, so there is no need to add additional external components, and the integration is relatively high.

[0029] (3) The unit with pressure relief function of the present invention is realized in a mechanical form and can still be realized when the aircraft is electrically pressed down. There are no restrictions on the conditions of use, it has strong applicability and good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to further illustrate the dual-mode hydraulic servo actuator with pressure relief function according to the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, wherein:

[0031] Figure 1 This is a schematic diagram of the principle of a traditional active-damping dual-working mode hydraulic servo actuator;

[0032] Figure 2 is a schematic diagram of the principle of a first embodiment of a hydraulic servo actuator with a pressure relief function according to the present invention;

[0033] Figure 3is a schematic diagram of the principle of a second embodiment of a hydraulic servo actuator with a pressure relief function according to the present invention; and

[0034] Figure 4 1 is a schematic diagram of the principle of a third embodiment of a hydraulic servo actuator with a pressure relief function according to the present invention.

[0035] Reference numerals

[0036] 1 Oil inlet connector

[0037] 2 Oil return connector

[0038] 3 Oil inlet filter

[0039] 4 Oil return back pressure valve

[0040] 5 Oil inlet check valve

[0041] 6 Servo valve

[0042] 7 First stage mode selector valve

[0043] 8 Second stage mode selector valve

[0044] 9 Variable damping valve

[0045] 10 Actuator

[0046] 10X First Chamber

[0047] 10Y second cavity

[0048] 11X First Pressure Relief Valve

[0049] 11Y Second pressure relief valve DETAILED DESCRIPTION

[0050] The structure and working principle of the dual-mode hydraulic servo actuator with pressure relief function according to the present invention will be described below with reference to the accompanying drawings.

[0051] It should be understood that the embodiments described in this specification only cover some embodiments of the present invention, not all embodiments. Based on the embodiments described in this specification, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of the present invention.

[0052] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned description of the drawings are intended to cover non-exclusive inclusions. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0053] Figure 2 The working principle of the first embodiment of the hydraulic servo actuator with pressure relief function according to the present invention is shown.

[0054] and Figure 1 Similarly, in the first embodiment of the present invention, the hydraulic servo actuator has an oil inlet pipeline with the oil inlet connector 1 as the starting point and an oil return pipeline with the oil return connector 2 as the node, wherein the oil inlet pipeline passes through the oil inlet filter 3 and is diverted to the servo valve 6 and the first-stage mode selection valve 7 via the oil inlet check valve 5, and the return oil pipeline is connected to the variable damping valve 9 via the return oil back pressure valve 4, wherein the servo valve 6 is a three-position four-way valve controlled by both electric current and hydraulic pressure, and the first-stage mode selection valve 7 is a two-position three-way valve controlled by electromagnetic.

[0055] The hydraulic servo actuator also features a second-stage mode selector valve 8 connected to the first-stage mode selector valve 7, the servo valve 6, and the variable damping valve 9, and an actuator 10 connected to the second-stage mode selector valve 8. The second-stage mode selector valve 8 is a two-position, six-way valve controlled by a hydraulic pilot. When the hydraulic source is available and the power supply is normal, the hydraulic servo actuator operates in the active mode (i.e., the first mode). In this state, the first-stage mode selector valve 7 is energized and connected to a relatively high-pressure oil inlet line via a control port, pushing the second-stage mode selector valve 8 to the first position 8X. In this first position 8X, the first and third control ports 6X and 6Z of the servo valve 6 are connected to the first chamber 10X and the second chamber 10Y of the actuator 10 via the second-stage mode selector valve 8, causing communication between the actuator 10 and the servo valve 6. The hydraulic servo actuator's linear output is controlled by the hydraulic flow, thereby controlling the reciprocating movement of the piston rod of the actuator 10.

[0056] When the hydraulic power source is lost or the power supply is abnormal, the hydraulic servo actuator enters damping mode (i.e., the second mode). At this point, the first-stage mode selector valve 7 is deenergized and / or hydraulic, and the second-stage mode selector valve 8 enters the second state position 8Y, connecting the first chamber 10X and the second chamber 10Y of the actuator cylinder 10 to the variable damping valve 9 via the second-stage mode selector valve 8. In this state, the hydraulic servo actuator does not actively output force, but can provide damping force, providing vibration suppression and ground gust damping protection for the hydraulic servo actuator.

[0057] Different from the traditional hydraulic servo actuator: in the first embodiment, the variable damping valve 9 is designed as a three-position three-way valve controlled by hydraulic pressure and mechanical spring force, that is, a state position is added to the traditional two-position three-way valve, namely the third state position or the pressure relief state position 9Z. This state position is switched between the damping and pressure relief (undampened) state positions through the manual maintenance component integrated on the shell to achieve undamped conduction between the first chamber 10X and the second chamber 10Y of the actuator cylinder 10 and the return oil pipeline.

[0058] In the second position 9Y, the first and second chambers 10X, 10Y of the actuator 10 communicate with the oil return line via a tiny overflow hole. When a pressure differential exists between the first and second chambers 10X, 10Y of the actuator 10, the variable damping valve 9 enters the first position 9X. The first and second chambers 10X, 10Y of the actuator 10 communicate with each other through the variable damping passage, balancing the pressures in the first and second chambers 10X, 10Y. Using the aforementioned maintenance assembly, the variable damping valve 9 enters the third position 9Z, resulting in undamped communication between the first and second chambers 10X, 10Y of the actuator 10 and the oil return line.

[0059] The hydraulic servo actuator effectively solves the problem of operational difficulties caused by the damping force during ground maintenance after the flight control actuator is powered down, significantly improves the operability and convenience of aircraft maintenance inspections, and thus improves the economy of aircraft operations.

[0060] Figure 3 The working principle of the second embodiment of the hydraulic servo actuator with pressure relief function according to the present invention is shown.

[0061] and Figure 1 Similarly, in the second embodiment of the present invention, the hydraulic servo actuator has an oil inlet pipeline with the oil inlet connector 1 as the starting point and an oil return pipeline with the oil return connector 2 as the node, wherein the oil inlet pipeline passes through the oil inlet filter 3 and is diverted to the servo valve 6 and the first-stage mode selection valve 7 via the oil inlet check valve 5, and the return oil pipeline is connected to the variable damping valve 9 via the return oil back pressure valve 4, wherein the servo valve 6 is a three-position four-way valve controlled by electric current and hydraulic pressure, and the first-stage mode selection valve 7 and the variable damping valve 9 are both designed as two-position three-way valves.

[0062] The hydraulic servo actuator also features a second-stage mode selector valve 8 connected to the first-stage mode selector valve 7, the servo valve 6, and the variable damping valve 9, and an actuator 10 connected to the second-stage mode selector valve 8. The second-stage mode selector valve 8 is a two-position, six-way valve controlled by a hydraulic pilot. When the hydraulic source is available and the power supply is normal, the hydraulic servo actuator operates in the active mode. At this point, the first-stage mode selector valve 7 is energized and connected to a relatively high-pressure oil inlet line via its control port, pushing the second-stage mode selector valve 8 to its first position 8X. In this first position 8X, the first and third control ports 6X and 6Z of the servo valve 6 are connected to the first chamber 10X and second chamber 10Y of the actuator 10 via the second-stage mode selector valve 8, causing electrical communication between the actuator 10 and the servo valve 6. The hydraulic servo actuator's linear output is controlled by the hydraulic flow, thereby controlling the reciprocating movement of the piston rod of the actuator 10.

[0063] To achieve the pressure relief function, this embodiment adds first pressure relief valves 11X and 11Y, respectively, between the first and second chambers 10X, 10Y of the actuator 10 and the secondary mode selector valve 8 . This allows for undamped communication between the first and second chambers 10X, 10Y of the actuator 10 and the oil return line.

[0064] Figure 4 The working principle of the third embodiment of the hydraulic servo actuator with pressure relief function according to the present invention is shown.

[0065] and Figure 1 Similarly, in the third embodiment of the present invention, the hydraulic servo actuator has an oil inlet pipeline with the oil inlet connector 1 as the starting point and an oil return pipeline with the oil return connector 2 as the node, wherein the oil inlet pipeline passes through the oil inlet filter 3 and is diverted to the servo valve 6 and the first-stage mode selection valve 7 via the oil inlet check valve 5, and the return oil pipeline is connected to the variable damping valve 9 via the return oil back pressure valve 4, wherein the servo valve 6 is a three-position four-way valve controlled by both electric current and hydraulic pressure, and the first-stage mode selection valve 7 and the variable damping valve 9 are both designed as two-position three-way valves.

[0066] The hydraulic servo actuator also features a second-stage mode selector valve 8 connected to the first-stage mode selector valve 7, the servo valve 6, and the variable damping valve 9, and an actuator 10 connected to the second-stage mode selector valve 8. The second-stage mode selector valve 8 is a two-position, six-way valve controlled by a hydraulic pilot. When the hydraulic source is available and the power supply is normal, the hydraulic servo actuator operates in the active mode. At this point, the first-stage mode selector valve 7 is energized and connected to a relatively high-pressure oil inlet line via its control port, pushing the second-stage mode selector valve 8 to its first position 8X. In this first position 8X, the first and third control ports 6X and 6Z of the servo valve 6 are connected to the first chamber 10X and the second chamber 10Y of the actuator 10 via the second-stage mode selector valve 8, causing electrical communication between the actuator 10 and the servo valve 6. The hydraulic servo actuator's linear output is controlled by the hydraulic flow, thereby controlling the reciprocating movement of the piston rod of the actuator 10.

[0067] In order to realize the pressure relief function, the present embodiment adds first pressure relief valves 11X and 11Y between the secondary mode selection valve 8 and the variable damping valve 9 to realize undamped conduction between the first chamber 10X and the second chamber 10Y of the actuator 10 and the return oil pipeline.

[0068] The above two embodiments, by designing the pressure relief valves 11X and 11Y to be integrated with the hydraulic servo actuator, do not require additional external components, and thus have a high degree of integration. Moreover, there are no restrictions on usage conditions, and the applicability is strong, which has great application value.

[0069] While the structure and operating principle of the dual-mode hydraulic servo actuator with a pressure relief function according to the present invention have been described above in conjunction with preferred embodiments and accompanying drawings, those skilled in the art will recognize that the above examples are for illustrative purposes only and are not intended to limit the present invention. Therefore, modifications and variations may be made to the present invention within the spirit of the appended claims, and such modifications and variations will fall within the scope of the appended claims.

Claims

1. A dual-mode hydraulic servo actuator comprising: An oil inlet pipeline starting from the oil inlet connector (1), wherein the oil inlet pipeline is branched to the servo valve (6) and the first-stage mode selection valve (7); an oil return line with the oil return joint (2) as a node, wherein the oil return line is connected to a variable damping valve (9); a second-stage mode selection valve (8), the second-stage mode selection valve (8) being connected to the first-stage mode selection valve (7), the servo valve (6) and the variable damping valve (9); and The actuator (10) is connected to the second-stage mode selection valve (8), and when the hydraulic servo actuator is in the first mode, the actuator (10) performs linear output. It is characterized in that the hydraulic servo actuator also includes a pressure relief unit. When the hydraulic servo actuator is in the second mode, the actuator cylinder (10) is connected to the variable damping valve (9) and the pressure relief unit. The pressure relief unit provides a maintenance interface and a release function for releasing the damping force, so that there is no damping conduction between the actuator cylinder (10) and the return oil pipeline.

2. The hydraulic servo actuator according to claim 1, wherein: The pressure relief unit is composed of a variable damping valve (9) in the form of a three-position three-way valve, which is controlled by hydraulic pressure and mechanical spring force.

3. The hydraulic servo actuator according to claim 2, wherein: When there is a pressure difference between the first chamber (10X) and the second chamber (10Y) of the actuator cylinder (10), the variable damping valve (9) enters the first state position (9X), connecting and balancing the pressure of the first chamber (10X) and the second chamber (10Y) of the actuator cylinder (10).

4. The hydraulic servo actuator according to claim 2, wherein: When the variable damping valve (9) is in the second state position (9Y), the first chamber (10X) and the second chamber (10Y) of the actuator (10) are connected to the return oil pipeline with damping, and when the variable damping valve (9) is in the third state position (9Z), non-damping conduction is achieved between the actuator (10) and the return oil pipeline, and between the first chamber (10X) and the second chamber (10Y) of the actuator (10).

5. The hydraulic servo actuator according to claim 1, wherein: The pressure relief unit is composed of a first pressure relief valve (11X) and a second pressure relief valve (11Y) arranged between the first chamber (10X) and the second chamber (10Y) of the actuator (10) and the secondary mode selection valve (8).

6. The hydraulic servo actuator according to claim 1, wherein: The pressure relief unit is composed of a first pressure relief valve (11X) and a second pressure relief valve (11Y) arranged between the secondary mode selection valve (8) and the variable damping valve (9).

7. The hydraulic servo actuator according to claim 1, wherein: The hydraulic servo actuator further comprises: an oil inlet filter (3) and an oil inlet check valve (5), wherein the oil inlet pipeline passes through the oil inlet filter (3) and is diverted to the servo valve (6) and the first-stage mode selection valve (7) via the oil inlet check valve (5); and An oil return back pressure valve (4), wherein the oil return pipeline is connected to the variable damping valve (9) via the oil return back pressure valve (4).

8. The hydraulic servo actuator according to claim 1, wherein: The servo valve (6) is a three-position four-way valve.

9. The hydraulic servo actuator according to claim 8, wherein: The servo valve (6) is controlled by both electric current and hydraulic pressure.

10. The hydraulic servo actuator according to claim 1, wherein: The first-stage mode selection valve (7) is a two-position three-way valve.

11. The hydraulic servo actuator according to claim 10, wherein: The first-stage mode selection valve (7) is controlled by electromagnetic.

12. The hydraulic servo actuator according to claim 1, wherein: The second-stage mode selection valve (8) is a two-position six-way valve.

13. The hydraulic servo actuator according to claim 12, wherein: The second-stage mode selection valve (8) is controlled by a hydraulic pilot.

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