Electro-hydraulic actuators and their applications

Abstract

This invention discloses an electro-hydraulic actuator and its application, comprising an electro-hydraulic actuator mechanism and a volume compensation mechanism connected to the electro-hydraulic actuator mechanism via pipelines. The electro-hydraulic actuator includes an energy accumulator, a motor, a cylinder assembly, and a hydraulic control valve assembly, all three of which are connected to the hydraulic control valve assembly via pipelines. The volume compensation mechanism includes an oil tank and a volume adjustment assembly fixedly disposed within the oil tank. The outlet pipeline of the oil tank is connected to the hydraulic control valve assembly, and the motor is disposed on the pipeline between the outlet of the oil tank and the hydraulic control valve assembly. The first inlet of the oil tank is connected to the energy accumulator and the hydraulic control valve assembly respectively via two straight pipelines. This application realizes an electro-hydraulic actuator and its application that can be placed omnidirectionally, has a high degree of automation, a simple structure, and can prevent impurities and moisture in the air from entering the actuator.

Description

Technical Field

[0001] This invention relates to the field of pipeline fluid safety control, and in particular to an electro-hydraulic actuator and its application. Background Technology

[0002] Actuators are an important component in industrial automatic control systems. They are devices used to drive and control valve operation and can directly affect control performance. They can be divided into three main categories: electric actuators, pneumatic actuators, and electro-hydraulic actuators. This invention mainly relates to electro-hydraulic actuators.

[0003] Traditional electro-hydraulic actuators can achieve high driving force control and are simple to operate, easy to adjust speed, highly accurate, fast in response, and low in noise. However, they require a hydraulic station, oil pipelines, and hydraulic control valve components, resulting in large size, high cost, and heavy maintenance, limiting their application to larger work environments. Furthermore, current electro-hydraulic actuators typically use oil tanks with vents to maintain stable oil pressure by allowing the oil level to be exposed to the atmosphere. During normal operation, outside air enters and exits the tank due to pressure changes, introducing moisture and impurities into the hydraulic oil and pipelines. Since they often operate in humid, dusty, and other harsh environments, electro-hydraulic actuators are prone to failure. Therefore, improving the reliability of electro-hydraulic actuators and promptly identifying operational problems are fundamental requirements for ensuring stable and safe process control. Further improvements to electro-hydraulic actuators are therefore necessary. Summary of the Invention

[0004] This invention solves the problem of air impurities and moisture entering the electro-hydraulic actuator during oil tank volume compensation in operation, affecting the control effect. It also provides an emergency automatic control device to ensure that the electro-hydraulic actuator can still be safely shut down in the event of a sudden power failure, without overly relying on the local power supply. It also has a self-protection function, which monitors the pressure value in the electro-hydraulic actuator system in real time. When the pressure value is too high, the protection circuit is activated to prevent malfunctions. Therefore, this invention provides an electro-hydraulic actuator and its application that is simple in structure, easy to operate, can monitor device malfunctions in real time to ensure safe operation, can be placed in all directions, and can completely prevent air impurities and moisture from entering the actuator.

[0005] In a first aspect, this application provides an electro-hydraulic actuator, which adopts the technical solution described below:

[0006] An electro-hydraulic actuator includes an electro-hydraulic actuator mechanism and a volume compensation mechanism. The volume compensation mechanism is connected to the electro-hydraulic actuator mechanism and is used to ensure the stable operation of the electro-hydraulic actuator mechanism. The electro-hydraulic actuator includes an energy accumulator, a motor, a cylinder assembly, and a hydraulic control valve assembly. The energy accumulator, the motor, and the cylinder assembly are all connected to the hydraulic control valve assembly via pipelines. The volume compensation mechanism includes an oil tank and a volume adjustment assembly. The volume adjustment assembly is fixedly installed inside the oil tank and affects the internal volume of the oil tank through its own volume changes. The outlet pipeline of the oil tank is connected to the hydraulic control valve assembly. The motor is installed on the connecting pipeline between the outlet of the oil tank and the hydraulic control valve assembly. The first inlet of the oil tank is connected to the energy accumulator and the hydraulic control valve assembly via two straight pipelines, respectively.

[0007] By adopting the above solution, a volume compensation device is installed in the oil tank, replacing the existing method of compensating the oil tank volume by opening a vent hole on the oil tank. This avoids impurities and moisture in the outside air from entering the oil tank and contaminating the hydraulic oil, thereby affecting the control effect of the electro-hydraulic actuator.

[0008] Furthermore, it makes the control circuit structure of the electro-hydraulic actuator simpler, the operation more convenient, the control more automated, and the operation safer.

[0009] Preferably, the hydraulic control valve assembly includes a first solenoid valve, a second solenoid valve, a third solenoid valve, and a fourth solenoid valve connected sequentially through a hydraulic control valve pipeline, and the first solenoid valve is connected to the fourth solenoid valve, so that the first solenoid valve, the second solenoid valve, the third solenoid valve, and the fourth solenoid valve form a loop.

[0010] By adopting the above scheme, the composition of the hydraulic control valve assembly is refined, providing technical support for the realization of the electro-hydraulic actuator control process. The electro-hydraulic actuator can open the valves in the entire automatic control system through the first and third solenoid valves, and close the valves in the entire automatic control system through the second and fourth solenoid valves.

[0011] Preferably, the energy storage device is connected to the hydraulic control valve assembly via a first pipeline, on which a third shut-off valve, a first pressure transmitter, and a fifth solenoid valve are sequentially arranged. The fifth solenoid valve is connected to the hydraulic control valve pipeline between the first solenoid valve and the fourth solenoid valve via the first pipeline.

[0012] By adopting the above scheme, the first pressure transmitter can monitor the pressure in the energy storage device in real time, and decide whether to control the flow of hydraulic oil in the oil tank to the energy storage device based on the pressure value in the energy storage device, making the whole device more automated and intelligent.

[0013] Preferably, the first oil port of the cylinder assembly is connected to the hydraulic control valve assembly via a second pipeline, the second pipeline being provided with a first shut-off valve, and the end of the second pipeline away from the first oil port being connected to the hydraulic control valve pipeline between the first solenoid valve and the second solenoid valve; the second oil port of the cylinder assembly is connected to the hydraulic control valve assembly via a third pipeline, the third pipeline being provided with a second shut-off valve, and the end of the third pipeline away from the second oil port being connected to the hydraulic control valve pipeline between the third solenoid valve and the fourth solenoid valve.

[0014] By adopting the above scheme, the connection relationship between the cylinder assembly and the hydraulic control valve assembly is refined, providing technical support for the control process of the electro-hydraulic actuator. Hydraulic oil enters the cylinder assembly from the first and third solenoid valves to drive the cylinder assembly to open, and enters the cylinder assembly from the second and fourth solenoid valves to drive the cylinder assembly to close.

[0015] Preferably, the volume adjustment assembly includes a bladder and a breather valve. The bladder is disposed inside the fuel tank, and the breather valve is fixedly disposed on the outer shell of the fuel tank. One end of the breather valve is fixedly connected to the vent of the bladder, and the other end of the breather valve extends out of the fuel tank.

[0016] By adopting the above solution, outside air enters and exits through the bladder in the oil tank via the breather valve, which can prevent impurities and moisture in the air from entering the oil tank and coming into contact with the hydraulic oil, thus affecting the quality of the hydraulic oil and the control effect of the entire electro-hydraulic actuator.

[0017] Preferably, the outlet of the oil tank is connected to the hydraulic control valve assembly via a fourth pipeline, the motor is mounted on the fourth pipeline, the fourth pipeline is also equipped with a filter and a second check valve, the inlet of the filter is connected to the oil tank, and the second check valve is connected to the hydraulic control valve assembly.

[0018] By adopting the above solution, the filter installed at the oil outlet of the oil tank can filter out impurities generated in the hydraulic oil as it passes through the actuator, thus preventing impurities from entering the actuator and affecting the control effect.

[0019] Preferably, a second pressure transmitter is also provided on the fourth pipeline, and the second pressure transmitter is disposed between the second check valve and the hydraulic control valve assembly.

[0020] By adopting the above scheme, the second pressure transmitter can monitor whether the pressure in the electro-hydraulic actuator system is within the set range in real time, and can promptly detect faults that occur during the operation of the electro-hydraulic actuator, thus ensuring operational safety.

[0021] Preferably, the first inlet of the oil tank is connected to the hydraulic control valve assembly through a first straight-through pipeline. A first check valve is provided on the first straight-through pipeline, and the inlet of the first check valve is connected to the hydraulic control valve pipeline between the second solenoid valve and the third solenoid valve through the first straight-through pipeline.

[0022] By adopting the above scheme, a first check valve is installed on the first straight-through pipeline of the hydraulic oil return tank, which ensures the flow direction of the hydraulic oil, prevents the hydraulic oil from flowing back, and further ensures the normal operation of the electro-hydraulic actuator and the reliability of the device.

[0023] Preferably, the first inlet of the oil tank is connected to the energy storage device through a second straight-through pipeline, and a fourth shut-off valve is provided on the second straight-through pipeline, which is normally closed.

[0024] By adopting the above scheme, a fourth shut-off valve is installed on the second straight-through pipeline between the energy accumulator and the oil tank. When the fourth shut-off valve is in a normally closed state, it can prevent the hydraulic oil in the energy accumulator from leaking into the oil tank during normal operation. When the fourth shut-off valve is opened, the hydraulic oil in the energy accumulator can flow into the oil tank, which facilitates the maintenance of the energy accumulator.

[0025] Preferably, the oil tank further includes a second liquid inlet, which is connected to the second check valve via a protection pipeline. A pressure protector is provided on the protection pipeline, and the inlet end of the pressure protector is connected to a fourth pipeline between the motor and the second check valve via the protection pipeline.

[0026] By adopting the above scheme, a pressure protector is installed at the inlet end of the second check valve. When the pressure in the system exceeds the set value during operation, the hydraulic oil delivered by the motor will preferentially enter the oil tank through the pressure protector, which can prevent the system pressure from being too high and causing a malfunction.

[0027] Secondly, this application provides an application of an electro-hydraulic actuator, specifically a valve control method. The method is implemented based on the aforementioned electro-hydraulic actuator, which is connected to and controls the operation of at least one external valve. The method includes the following steps:

[0028] Put the electro-hydraulic actuator into working mode.

[0029] When the motor rotates forward, the first and third solenoid valves change from the closed to the open state. Hydraulic oil in the tank enters the cylinder assembly through the first solenoid valve, pushing the cylinder assembly to open. Hydraulic oil then flows back to the tank through the third solenoid valve. At this time, the external valve opens.

[0030] When the motor reverses, the first and third solenoid valves close, while the second and fourth solenoid valves open. Hydraulic oil in the tank enters the cylinder assembly via the fourth solenoid valve, pushing the cylinder assembly to close. Hydraulic oil then flows back to the tank via the second solenoid valve. At this time, the external valve closes.

[0031] In the current mode, when the hydraulic oil in the oil tank flows out, the pressure inside the oil tank decreases, and outside air enters the bladder through the breather valve, causing the bladder to inflate and the volume compensation state to begin; when the hydraulic oil flows back to the oil tank, the pressure inside the oil tank increases, the air in the bladder is squeezed out, and the volume compensation state ends.

[0032] Put the electro-hydraulic actuator into energy storage mode.

[0033] The first pressure transmitter monitors the pressure value in the energy storage device in real time. When the pressure value in the energy storage device is lower than the preset lower pressure limit, the fifth solenoid valve changes from the closed state to the open state, and the hydraulic oil in the oil tank enters the energy storage device through the fifth solenoid valve.

[0034] In the current mode, when the hydraulic oil in the oil tank flows out, outside air enters the bladder through the breather valve, causing the bladder to inflate and the volume compensation state to begin.

[0035] Put the electro-hydraulic actuator into a power-off mode.

[0036] The second solenoid valve, the fourth solenoid valve, and the fifth solenoid valve are all powered by their own batteries. The hydraulic oil in the energy storage device first enters the cylinder assembly through the fifth solenoid valve and the fourth solenoid valve, and pushes the cylinder assembly to close. Then it flows into the oil tank through the second solenoid valve.

[0037] In the current mode, the hydraulic oil in the energy storage device flows into the oil tank, the pressure inside the oil tank increases, the air inside the bladder is squeezed out, and the volume compensation state ends.

[0038] By adopting the above technical solutions, a complete control system was built, providing necessary technical support for the control and operation of electro-hydraulic actuators, significantly improving the intelligence and automation level of electro-hydraulic actuator control technology, and meeting the requirements of technological progress.

[0039] In summary, this application has at least the following beneficial effects:

[0040] 1. This application monitors in real time whether the pressure in the electro-hydraulic actuator system is too high. If the pressure exceeds the set value, a self-protection mechanism is activated to prevent hydraulic oil from entering the system, thus ensuring the safe operation of the electro-hydraulic actuator.

[0041] 2. This application provides a power failure protection mechanism for electro-hydraulic actuators, ensuring that the electro-hydraulic actuators can shut down normally even when the device is suddenly powered off, thus enhancing the safety of the electro-hydraulic actuators;

[0042] 3. This application uses a volume compensation adjustment component to replace the traditional method of opening holes in the oil tank for volume compensation, which avoids impurities and moisture in the air from entering the oil tank and contaminating the hydraulic oil, thereby affecting the normal operation of the electro-hydraulic actuator. Furthermore, the electro-hydraulic actuator can be placed in all directions using this method. Attached Figure Description

[0043] Figure 1 This is a schematic diagram illustrating the working principle of the electro-hydraulic actuator and its application according to an embodiment of this application;

[0044] Figure 2 This is a cross-sectional view of the volume compensation oil tank according to an embodiment of this application;

[0045] Figure 3 This is a bottom view of the volume-compensating oil tank according to an embodiment of this application;

[0046] Figure 4 This is a flowchart illustrating the energy storage process of an energy storage device according to an embodiment of this application.

[0047] The components are as follows: 1. Energy accumulator; 2. Motor; 3. Hydraulic cylinder assembly; 4. Oil tank; 5. First solenoid valve; 6. Second solenoid valve; 7. Third solenoid valve; 8. Fourth solenoid valve; 9. Third shut-off valve; 10. First pressure transmitter; 11. Fifth solenoid valve; 12. First shut-off valve; 13. Second shut-off valve; 14. Leakage bellows; 15. Breathing valve; 16. Filter; 17. Second check valve; 18. Second pressure transmitter; 19. First check valve; 20. Fourth shut-off valve; 21. Pressure protector; 22. Oil window; 23. Oil tank cover; 24. Plug; 25. Screw. Detailed Implementation

[0048] This application provides an electro-hydraulic actuator and its application. To make the purpose, technical solution and advantages of this application clearer, the embodiments of this application will be described in further detail below.

[0049] The following description, in conjunction with the accompanying drawings, provides a further detailed description of an electro-hydraulic actuator of this application and its application.

[0050] This application discloses an electro-hydraulic actuator, such as... Figure 1 As shown, it includes an electro-hydraulic actuator and a volumetric compensation mechanism. The volumetric compensation mechanism is connected to the electro-hydraulic actuator and is used to ensure the stable operation of the electro-hydraulic actuator.

[0051] The electro-hydraulic actuator includes an accumulator 1, a motor 2, a cylinder assembly 3, and a hydraulic control valve assembly. The hydraulic control valve assembly includes a first solenoid valve 5, a second solenoid valve 6, a third solenoid valve 7, and a fourth solenoid valve 8. These four valves are sequentially connected to the hydraulic control valve pipeline, with the first solenoid valve 5 connected to the fourth solenoid valve 8, forming a loop among them. Figure 1 The dashed box in the middle shows the hydraulic control valve pipeline.

[0052] A third shut-off valve 9, a first pressure transmitter 10, and a fifth solenoid valve 11 are sequentially installed on the first pipeline between the energy storage device 1 and the hydraulic control valve assembly. The fifth solenoid valve 11 is connected to the hydraulic control valve pipeline between the first solenoid valve 5 and the fourth solenoid valve 8 through the first pipeline.

[0053] It should be noted that all solenoid valves are normally closed, and all solenoid valves of the electro-hydraulic actuator are connected to the central control unit. The opening or closing status of all solenoid valves is controlled by the central control unit.

[0054] The first oil port of the cylinder assembly 3 is connected to the hydraulic control valve assembly through a second pipeline. A first shut-off valve 12 is installed on the second pipeline. The end of the second pipeline away from the first oil port is connected to the hydraulic control valve pipeline between the first solenoid valve 5 and the second solenoid valve 6. The second oil port of the cylinder assembly 3 is connected to the hydraulic control valve assembly through a third pipeline. A second shut-off valve 13 is installed on the third pipeline. The end of the third pipeline away from the second oil port is connected to the hydraulic control valve pipeline between the third solenoid valve 7 and the fourth solenoid valve 8.

[0055] The volume compensation mechanism includes the fuel tank 4 and the volume adjustment assembly, such as... Figure 2 and Figure 3 As shown, oil windows 22 are opened on both sides of the oil tank 4. A plug 24 and a screw 25 are provided on the oil tank cover 23. The oil windows 22 allow technicians to observe the remaining amount of hydraulic oil in the oil tank and decide whether to add hydraulic oil to the oil tank 4. The plug 23 blocks the vent hole on the conventional oil tank, and the screw 24 is tightened to fix the oil tank cover 25.

[0056] The volume regulating component is fixedly installed inside the fuel tank 4. It affects the internal volume of the fuel tank 4 by changing its own volume. The volume regulating component includes a bladder 14 and a breather valve 15. The bladder 14 is installed inside the fuel tank 4, and the breather valve 15 is fixedly installed on the outer shell of the fuel tank 4. One end of the breather valve 15 is fixedly connected to the vent of the bladder 14, and the other end of the breather valve 15 extends out of the fuel tank 4 and is connected to the outside atmosphere to maintain the stability of the internal pressure of the fuel tank 4.

[0057] The outlet of the oil tank 4 is connected to the hydraulic control valve assembly through the fourth pipeline. The fourth pipeline is equipped with a motor 2, a filter 16, a second check valve 17, and a second pressure transmitter 18. The inlet of the filter 16 is connected to the oil tank 4. The second check valve 17 is connected to the hydraulic control valve assembly. The second pressure transmitter 18 is located between the second check valve 17 and the hydraulic control valve assembly.

[0058] The first inlet of the oil tank 4 is connected to the hydraulic control valve assembly through the first through pipe, and the first check valve 19 is connected to the hydraulic control valve pipeline between the second solenoid valve 6 and the third solenoid valve 7 through the first through pipe.

[0059] The first inlet of the oil tank 4 is connected to the energy storage device 1 through the second straight pipe, and the second straight pipe is equipped with a fourth shut-off valve 20.

[0060] The oil tank 4 also includes a second liquid inlet, which is connected to the second check valve 17 via a protection pipeline. A pressure protector 21 is installed on the protection pipeline, and the inlet end of the pressure protector 21 is connected to the fourth pipeline between the motor 2 and the second check valve 17 via the protection pipeline.

[0061] Under normal conditions, the first shut-off valve 12, the second shut-off valve 13, and the third shut-off valve 9 in the electro-hydraulic actuator are normally open, while the fourth shut-off valve 20 is normally closed.

[0062] The working process of the electro-hydraulic actuator described above is as follows: After receiving the valve opening signal from the external valve, the central control device controls the motor 2 to start rotating forward according to the valve opening signal. At the same time, the central control device controls the first solenoid valve 5 and the third solenoid valve 7 to open, while the remaining solenoid valves remain closed. Hydraulic oil enters the cylinder assembly 3 through the first solenoid valve 5, thereby causing the cylinder assembly 3 to start working. The piston inside the cylinder assembly 3 moves, and the hydraulic oil pushes the cylinder assembly 3 to open, thus opening the external valve. The hydraulic oil then enters the oil tank 4 through the third solenoid valve 7. During the opening of the external valve, when the hydraulic oil flows out of the oil tank 4, the pressure inside the oil tank 4 will decrease. At this time, the pressures at both ends of the breather valve 15 are inconsistent, and outside air will enter the bladder 14 through the breather valve 15, causing the bladder 14 to inflate, and the volume compensation state of the oil tank 4 begins. After the hydraulic oil pushes the external valve to open, it flows back into the oil tank 4, increasing the pressure inside the oil tank 4. The air in the bladder 14 is squeezed out through the breather valve 15, the pressure inside the oil tank 4 returns to normal, and the volume compensation state ends.

[0063] If the central control unit receives a valve closing signal from the external valve, it controls motor 2 to start reversing according to the valve closing signal. At the same time, the central control unit controls the second solenoid valve 6 and the fourth solenoid valve 8 to open, while the remaining solenoid valves close. Hydraulic oil flows out of the oil tank 4, passes through the fourth solenoid valve 8 and enters the cylinder assembly 3, pushing the cylinder assembly 3 to close. The external valve closes, and the hydraulic oil flows back to the oil tank 4 through the second solenoid valve 6. During the closing of the external valve, when the hydraulic oil flows out of the oil tank 4, the pressure inside the oil tank 4 decreases. At this time, the pressures at both ends of the breather valve 15 are inconsistent, and outside air enters the bladder 14 through the breather valve 15, causing the bladder 14 to inflate. The volume compensation state of the oil tank 4 begins. After the hydraulic oil pushes the external valve to close, it flows back into the oil tank 4, increasing the pressure inside the oil tank 4. The air in the bladder 14 is squeezed out through the breather valve 15, the pressure inside the oil tank 4 returns to normal, and the volume compensation state ends.

[0064] The electro-hydraulic actuator also has an energy storage mode for storing energy in the energy storage unit 1. The energy storage unit 1 is connected to the hydraulic control valve assembly via a first pipeline. The first pipeline is sequentially equipped with a third shut-off valve 9, a first pressure transmitter 10, and a fifth solenoid valve 11. The fifth solenoid valve 11 is connected to the hydraulic control valve pipeline between the first solenoid valve 5 and the fourth solenoid valve 8 via the first pipeline. The first pressure transmitter 10 is located between the fifth solenoid valve 11 and the third shut-off valve 9, and is connected to the central control device. The first pressure transmitter 10 has two pressure limits, P1 and P2. The trigger condition for the energy storage unit 1 to perform energy storage is that the pressure in the energy storage unit 1 is lower than the set pressure value P1.

[0065] The working principle of energy storage is as follows: Figure 4 As shown, the central control unit controls the first pressure transmitter 10 to monitor the pressure in the energy storage tank 1 in real time, and the first pressure transmitter 10 feeds back the pressure signal of the energy storage tank 1 to the central control unit. When the pressure value of the energy storage tank 1 is lower than the lower limit pressure P1, the central control unit turns on the power to the motor 2 and the fifth solenoid valve 11 to start working, and the other solenoid valves are closed. Hydraulic oil flows out from the oil tank 4, passes through the fifth solenoid valve 11 and the third shut-off valve 9 and flows into the energy storage tank 1 for energy storage. When the pressure in the first pressure transmitter 10 reaches the upper limit pressure value P2, the central control unit disconnects the power to the motor 2 and closes the valve of the fifth solenoid valve 11, and the energy storage ends.

[0066] The normal energy storage range for accumulator 1 is: P1 < pressure in accumulator 1 < P2. When the pressure in accumulator 1 is less than P1, it is insufficient to support the action of closing the hydraulic cylinder assembly 3 in the power-off state, and therefore cannot complete the work of closing the external valve. When the pressure is greater than P2, the pressure in accumulator 1 is too high, which can easily cause malfunctions. Therefore, when the pressure in accumulator 1 reaches P2, energy storage ends. During the energy storage process, hydraulic oil continuously enters accumulator 1 from oil tank 4. At this time, the pressure in oil tank 4 decreases, and outside air enters bladder 14 through breather valve 15, causing bladder 14 to inflate. The pressure in oil tank 4 returns to normal, and the volume compensation state ends.

[0067] The electro-hydraulic actuator controls the first pressure transmitter 10 through the central control device to monitor the pressure value in the energy storage device 1 in real time, which can realize the automatic start and stop of energy storage operation without manual intervention, making the electro-hydraulic actuator more automated and intelligent.

[0068] As mentioned above, the energy storage in the energy storage device 1 is for the purpose of closing the external valve during power failure. Therefore, to cope with sudden power failures of the electro-hydraulic actuator, the third solenoid valve 7, the fourth solenoid valve 8, and the fifth solenoid valve 11 of the electro-hydraulic actuator in this embodiment are all equipped with batteries. The central control device can control the batteries of the third solenoid valve 7, the fourth solenoid valve 8, and the fifth solenoid valve 11 to supply power to the three solenoid valves, so that all three solenoid valves can continue to operate normally to ensure the normal closure of the external valve.

[0069] The specific working process is as follows: When the electro-hydraulic actuator is not powered, the fifth solenoid valve 11 is closed; when the electro-hydraulic actuator is de-powered, the central control device controls the batteries of the third solenoid valve 7, the fourth solenoid valve 8, and the fifth solenoid valve 11 to supply power to all three, at which time the fifth solenoid valve 11 changes from closed to open. The hydraulic oil in the accumulator 1 first passes through the fifth solenoid valve 11 and the fourth solenoid valve 8 into the cylinder assembly 3, pushing the cylinder assembly 3 to close. The hydraulic oil then passes through the third solenoid valve 7 into the oil tank 4, and the external valve closes. During the closing process of the external valve, the hydraulic oil flows out of the accumulator 1 to complete the action of pushing the external valve to close before flowing back into the oil tank 4. The pressure in the oil tank 4 increases, the air in the bladder 14 is squeezed out, the pressure in the oil tank 4 returns to normal, and the volume compensation ends.

[0070] This embodiment ensures that the electro-hydraulic actuator will not suddenly stop working and affect the performance of the entire electro-hydraulic actuator when the power is suddenly cut off. The third solenoid valve 7, the fourth solenoid valve 8 and the fifth solenoid valve 11 with built-in batteries can continue to work. The oil in the energy storage tank 1 can also be used as an oil source to support the safe closure of the external valves, making the electro-hydraulic actuator more reliable.

[0071] Regardless of whether it is in working mode, energy storage mode or power failure mode, there will be pressure changes in oil tank 4. In all three modes, the electro-hydraulic actuator compensates for the internal volume of oil tank 4 by a volume adjustment component fixedly installed inside oil tank 4. The volume adjustment assembly includes a bladder 14 and a breather valve 15. The breather valve 15 is fixed to the outer shell of the oil tank 4. The vent of the bladder 14 is fixedly connected to one end of the breather valve 15, and the other end of the breather valve 15 extends out of the oil tank 4 and is in communication with the outside atmosphere. When hydraulic oil flows out of the oil tank 4, the pressure inside the oil tank 4 decreases. At this time, the pressures at both ends of the breather valve 15 are inconsistent, and outside air enters the bladder 14 through the breather valve 15, causing the bladder 14 to inflate and the volume compensation state of the oil tank 4 to begin. After hydraulic oil flows into the oil tank 4, the pressure inside the oil tank 4 increases. At this time, the air in the bladder 14 is squeezed out through the breather valve 15, and the volume compensation state ends. It should be noted that the volume compensation state is the process in which the volume of the bladder 14 inside the oil tank 4 increases due to the entry of outside air to make up for the volume of the outflowing hydraulic oil.

[0072] This volume compensation method is achieved by the movement of outside air entering and exiting the bladder 14, completely isolating the volume compensation action inside the bladder 14, preventing impurities and moisture in the outside air from entering the oil tank 4 and contaminating the hydraulic oil, thus further ensuring the accuracy of the electro-hydraulic actuator control process.

[0073] The electro-hydraulic actuator has a filter 16, which is located between the oil tank 4 and the motor 2. The filter 16 can filter the hydraulic oil after it flows out of the oil tank 4, filtering out metal shavings and other impurities generated inside the electro-hydraulic actuator during operation, thus ensuring the normal operation of the electro-hydraulic actuator.

[0074] To enable fault monitoring, the second pressure transmitter 18 is installed between the second check valve 17 and the hydraulic control valve assembly via a fourth pipeline. The second pressure transmitter 18 can monitor in real time whether the pressure in the electro-hydraulic actuator system is within the set range, which is beneficial for timely detection of faults in the electro-hydraulic actuator device.

[0075] A first check valve 19 is installed on the first straight-through pipeline between the first inlet of the oil tank 4 and the hydraulic control valve assembly. The inlet of the first check valve 19 is connected to the hydraulic control valve pipeline between the second solenoid valve 6 and the third solenoid valve 7 through the first straight-through pipeline. The first check valve 19 ensures the flow of hydraulic oil and prevents backflow of hydraulic oil into the oil tank 4, thus ensuring the safe operation of the electro-hydraulic actuator.

[0076] To facilitate the maintenance of the accumulator 1, the fourth shut-off valve 20 in this embodiment is installed on the second straight-through pipeline between the accumulator 1 and the oil tank 4. When the electro-hydraulic actuator is working normally, the fourth shut-off valve 20 is normally closed to prevent hydraulic oil in the accumulator 1 from leaking into the oil tank 4. When the accumulator 1 malfunctions or requires periodic maintenance, the fourth shut-off valve 20 is opened, allowing the hydraulic oil in the accumulator 1 to flow into the oil tank 4, facilitating maintenance of the accumulator 1 and further improving the reliability of the electro-hydraulic actuator itself.

[0077] To achieve the self-protection function of the electro-hydraulic actuator, a pressure protector 21 is installed on the protection pipeline between the motor 2 and the second check valve 17. Under working conditions, when the second pressure transmitter 18 detects that the pressure in the electro-hydraulic actuator system is higher than the set pressure value, the hydraulic oil delivered by the motor 2 will preferentially enter the oil tank 4 through the pressure protector 21, which can prevent the electro-hydraulic actuator system from malfunctioning due to excessive pressure and further ensure the safe operation of the electro-hydraulic actuator.

[0078] The aforementioned electro-hydraulic actuator device comprehensively solves some of the technical problems that occur in traditional electro-hydraulic actuators. It enables the electro-hydraulic actuator to automatically detect faults and activate its self-protection mechanism. It also avoids the hydraulic oil being contaminated by impurities in the air during the volume compensation process and achieves the effect of allowing the electro-hydraulic actuator device to be placed in any location. This makes the operation of the electro-hydraulic actuator device more convenient and ensures greater safety and control precision.

[0079] Based on the same inventive concept described above, this application also discloses an application of an electro-hydraulic actuator, specifically a valve control method. The method is implemented based on the aforementioned electro-hydraulic actuator, which is connected to and controls the operation of at least one external valve. The method includes the following steps:

[0080] S1. Adjust the electro-hydraulic actuator to put it into working mode;

[0081] When the central control device receives the valve opening signal from the external valve, it connects the power supply to the motor 2 according to the valve opening signal and controls the motor 2 to start rotating forward. At the same time, the central control device controls the first solenoid valve 5 and the third solenoid valve 7 to change from the closed state to the open state, while the other solenoid valves remain closed. At this time, the hydraulic oil in the oil tank 4 enters the oil cylinder assembly 3 through the first solenoid valve 5, pushing the piston inside the oil cylinder assembly 3 to move. The oil cylinder assembly 3 opens, and the hydraulic oil flows back to the oil tank 4 through the third solenoid valve 7. At this time, the external valve opens.

[0082] When the central control unit receives the valve closing signal from the external valve, it connects the power supply to the motor 2 according to the valve closing signal and controls the motor 2 to start reversing. At this time, the central control unit controls the first solenoid valve 5 and the third solenoid valve 7 to change from the open state to the closed state, and the second solenoid valve 6 and the fourth solenoid valve 8 to change from the closed state to the open state. The hydraulic oil in the oil tank 4 enters the oil cylinder assembly 3 through the fourth solenoid valve 8, pushing the piston inside the oil cylinder assembly 3 to move. When the oil cylinder assembly 3 closes, the hydraulic oil flows back to the oil tank 4 through the second solenoid valve 6. At this time, the external valve closes.

[0083] It should be noted that, under the current working mode, when the hydraulic oil in the oil tank 4 flows out, the pressure inside the oil tank 4 decreases, the pressure at both ends of the breather valve 15 is inconsistent, and outside air enters the bladder 14 through the breather valve 15, causing the bladder 14 to bulge and the volume compensation state to begin; when the hydraulic oil flows back to the oil tank 4, the pressure inside the oil tank 4 increases, and the air in the bladder 14 is squeezed out through the breather valve 15, ending the volume compensation state.

[0084] S2. Adjust the electro-hydraulic actuator to put it into energy storage mode;

[0085] The central control unit controls the first pressure transmitter 10 to monitor the pressure value in the energy storage 1 in real time and feeds back the pressure signal to the central control unit. When the pressure value in the energy storage 1 is lower than the lower limit pressure value P1, the central control unit turns on the power to the motor 2 and the fifth solenoid valve 11, so that the fifth solenoid valve 11 changes from the closed state to the open state. The hydraulic oil in the oil tank 4 enters the energy storage 1 through the fifth solenoid valve 11. Until the first pressure transmitter 10 monitors that the pressure value in the energy storage 1 reaches the upper limit pressure value P2, the central control unit controls the motor 2 to stop working.

[0086] It should be noted that in the current energy storage mode, when the hydraulic oil in the oil tank 4 flows out, the pressure inside the oil tank 4 decreases, and outside air enters the bladder 14 through the breather valve 15, causing the bladder 14 to bulge and the volume compensation state to begin.

[0087] S3. Adjust the electro-hydraulic actuator to put it in the power-off mode;

[0088] The central control unit controls the self-contained batteries of the second solenoid valve 6, the fourth solenoid valve 8 and the fifth solenoid valve 11 to power the three valves. All three valves are in the open state. Then, the hydraulic oil in the energy storage unit 1 first enters the cylinder assembly 3 through the fifth solenoid valve 11 and the fourth solenoid valve 8, and pushes the cylinder assembly 3 to close. Then, it flows into the oil tank 4 through the second solenoid valve 6.

[0089] It should be noted that in the current power outage mode, the hydraulic oil in the energy storage device 1 flows into the oil tank 4, the pressure in the oil tank 4 increases, the air in the bladder 14 is squeezed out, and the volume compensation state ends.

[0090] The above-described method enables precise control of external valves by the electro-hydraulic actuator, provides an emergency solution in case of power failure, makes the operation and control process more reliable, and completely isolates the volume compensation process within the volume adjustment component, ensuring the stable operation of the electro-hydraulic actuator.

[0091] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. An electro-hydraulic actuator, characterized in that: The device includes an electro-hydraulic actuator and a volume compensation mechanism. The volume compensation mechanism is connected to the electro-hydraulic actuator and is used to ensure the stable operation of the electro-hydraulic actuator. The electro-hydraulic actuator includes an energy accumulator (1), a motor (2), a cylinder assembly (3), and a hydraulic control valve assembly. The energy accumulator (1), the motor (2), and the cylinder assembly (3) are all connected to the hydraulic control valve assembly via pipelines. The volume compensation mechanism includes an oil tank (4) and a volume adjustment assembly. The volume adjustment assembly is fixedly installed inside the oil tank (4) and affects the internal volume of the oil tank (4) through its own volume changes. The outlet pipeline of the oil tank (4) is connected to the hydraulic control valve assembly. The motor (2) is installed on the connecting pipeline between the outlet of the oil tank (4) and the hydraulic control valve assembly. The first inlet of the oil tank (4) is connected to the energy storage device (1) and the hydraulic control valve assembly through two straight pipelines respectively. The hydraulic control valve assembly includes a first solenoid valve (5), a second solenoid valve (6), a third solenoid valve (7) and a fourth solenoid valve (8) connected in sequence through the hydraulic control valve pipeline. The first solenoid valve (5) is connected to the fourth solenoid valve (8), so that the first solenoid valve (5), the second solenoid valve (6), the third solenoid valve (7) and the fourth solenoid valve (8) form a loop. The energy storage device (1) is connected to the hydraulic control valve assembly through a first pipeline. The first pipeline is sequentially provided with a third shut-off valve (9), a first pressure transmitter (10) and a fifth solenoid valve (11). The fifth solenoid valve (11) is connected to the hydraulic control valve pipeline between the first solenoid valve (5) and the fourth solenoid valve (8) through the first pipeline. The first pressure transmitter (10) is used to monitor the pressure value of the energy storage device (1); the outlet of the oil tank (4) is connected to the hydraulic control valve assembly through the fourth pipeline, and the fourth pipeline is equipped with a second pressure transmitter (18) for monitoring the pressure in the hydraulic circuit.

2. The electro-hydraulic actuator according to claim 1, characterized in that: The first oil port of the cylinder assembly (3) is connected to the hydraulic control valve assembly through a second pipeline. A first shut-off valve (12) is provided on the second pipeline. The end of the second pipeline away from the first oil port is connected to the hydraulic control valve pipeline between the first solenoid valve (5) and the second solenoid valve (6). The second oil port of the cylinder assembly (3) is connected to the hydraulic control valve assembly through a third pipeline. A second shut-off valve (13) is provided on the third pipeline. The end of the third pipeline away from the second oil port is connected to the hydraulic control valve pipeline between the third solenoid valve (7) and the fourth solenoid valve (8).

3. The electro-hydraulic actuator according to claim 1, characterized in that: The volume adjustment assembly includes a bladder (14) and a breathing valve (15). The bladder (14) is disposed inside the oil tank (4), and the breathing valve (15) is fixedly disposed on the outer shell of the oil tank (4). One end of the breathing valve (15) is fixedly connected to the vent of the bladder (14), and the other end of the breathing valve (15) extends out of the oil tank (4).

4. The electro-hydraulic actuator according to claim 1, characterized in that: The outlet of the oil tank (4) is connected to the hydraulic control valve assembly through a fourth pipeline. The motor (2) is installed on the fourth pipeline. The fourth pipeline is also equipped with a filter (16) and a second check valve (17). The inlet of the filter (16) is connected to the oil tank (4), and the second check valve (17) is connected to the hydraulic control valve assembly.

5. The electro-hydraulic actuator according to claim 4, characterized in that: The second pressure transmitter (18) is disposed between the second check valve (17) and the hydraulic control valve assembly.

6. The electro-hydraulic actuator according to claim 1, characterized in that: The first inlet of the oil tank (4) is connected to the hydraulic control valve assembly through the first straight-through pipeline. A first check valve (19) is provided on the first straight-through pipeline. The inlet of the first check valve (19) is connected to the hydraulic control valve pipeline between the second solenoid valve (6) and the third solenoid valve (7) through the first straight-through pipeline.

7. The electro-hydraulic actuator according to claim 1, characterized in that: The first inlet of the oil tank (4) is connected to the energy storage device (1) through a second straight pipe. A fourth shut-off valve (20) is provided on the second straight pipe. The fourth shut-off valve (20) is normally closed.

8. The electro-hydraulic actuator according to claim 4, characterized in that: The oil tank (4) also includes a second liquid inlet, which is connected to the second one-way valve (17) through a protection pipeline. A pressure protector (21) is provided on the protection pipeline. The liquid inlet of the pressure protector (21) is connected to the fourth pipeline between the motor (2) and the second one-way valve (17) through the protection pipeline.

9. An application of an electro-hydraulic actuator, based on the electro-hydraulic actuator as described in any one of claims 3, wherein the electro-hydraulic actuator is connected to and controls the operation of at least one external valve, characterized in that, Includes the following steps: Put the electro-hydraulic actuator into working mode. When the motor (2) rotates forward, the first solenoid valve (5) and the third solenoid valve (7) change from the closed state to the open state. The hydraulic oil in the oil tank (4) enters the cylinder assembly (3) through the first solenoid valve (5) and pushes the cylinder assembly (3) to open. The hydraulic oil flows back to the oil tank (4) through the third solenoid valve (7). At this time, the external valve opens. When the motor (2) reverses, the first solenoid valve (5) and the third solenoid valve (7) close, and the second solenoid valve (6) and the fourth solenoid valve (8) open. The hydraulic oil in the oil tank (4) enters the cylinder assembly (3) through the fourth solenoid valve (8) and pushes the cylinder assembly (3) to close. The hydraulic oil flows back to the oil tank (4) through the second solenoid valve (6). At this time, the external valve closes. In the current mode, when the hydraulic oil in the oil tank (4) flows out, the pressure inside the oil tank (4) decreases, and outside air enters the bladder (14) through the breather valve (15), causing the bladder (14) to bulge and the volume compensation state to begin; when the hydraulic oil flows back to the oil tank (4), the pressure inside the oil tank (4) increases, the air inside the bladder (14) is squeezed out, and the volume compensation state ends. Put the electro-hydraulic actuator into energy storage mode. The first pressure transmitter (10) monitors the pressure value in the energy storage device (1) in real time. When the pressure value in the energy storage device (1) is lower than the preset lower pressure limit, the fifth solenoid valve (11) changes from the closed state to the open state, and the hydraulic oil in the oil tank (4) enters the energy storage device (1) through the fifth solenoid valve (11). In the current mode, when the hydraulic oil in the oil tank (4) flows out, outside air enters the bladder (14) through the breather valve (15), and the bladder (14) inflates and the volume compensation state begins; Put the electro-hydraulic actuator into a power-off mode. The second solenoid valve (6), the fourth solenoid valve (8) and the fifth solenoid valve (11) are all powered by their own batteries. The hydraulic oil in the energy storage device (1) first enters the cylinder assembly (3) through the fifth solenoid valve (11) and the fourth solenoid valve (8), and pushes the cylinder assembly (3) to close, and then flows into the oil tank (4) through the second solenoid valve (6). In the current mode, the hydraulic oil in the energy storage device (1) flows into the oil tank (4), the pressure in the oil tank (4) increases, the air in the bladder (14) is squeezed out, and the volume compensation state ends.

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