An electro-hydraulic actuator hydraulic system and hydraulic control system

Abstract

The present invention discloses an electro-hydraulic actuator hydraulic system, which belongs to the technical field of hydraulic systems. The hydraulic system of the present invention includes a double-piston rod cylinder, a motor, a hydraulic gear pump, an oil tank, a hydraulic oil circuit and an accumulator. The motor is connected to the hydraulic gear pump, and the hydraulic gear pump is connected to the accumulator through a hydraulic oil circuit. A pressure sensor is provided in the hydraulic oil circuit. The advantages of the present invention are: ① The present invention adopts an electro-hydraulic integrated, integrated, modular and miniaturized design, which is easy to realize serialization, simple structure, small size, no need for external oil and gas sources, high reliability, long service life, easy installation and adjustment, small maintenance workload, maintenance-free, and strong adaptability to the use environment; ② The present invention has standard analog and pulse signal control methods, is easy to interface with a controller, and accepts control signals from any control system.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic systems, and in particular to an electro-hydraulic actuator hydraulic system and a hydraulic control system. Background Art

[0002] An electro-hydraulic actuator is an actuator that converts a standard input signal (4-20mA, DC) into a corresponding 0- to 90-degree angular displacement output torque or linear displacement output force through electro-hydraulic conversion and hydraulic amplification. Currently, traditional electro-hydraulic servo actuators primarily consist of an electric motor, hydraulic pump, check valve, pressure relay, pressure gauge 14, filter, accumulator 21, servo valve, dual one-way throttle valve, hydraulic cylinder, relief valve, and oil tank 1. They utilize an open-circuit hydraulic system, controlling the servo valve to adjust the direction and flow of hydraulic oil, thereby driving the controlled object with a linear (or angular) displacement output force (or torque).

[0003] Existing equipment also has the following shortcomings: manually controlled equipment takes a long time to operate and cannot operate automatically in an emergency; electric equipment has high control accuracy, but cannot operate once the power is lost; pneumatic equipment has insufficient control accuracy and is overly dependent on the on-site air source. The unstable air pressure leads to unstable equipment operation. Summary of the Invention

[0004] The present invention aims to solve the problem that existing equipment has a long operating time and cannot realize the self-protection function of power failure, high temperature and other faults and cannot operate after power failure, and provides an electro-hydraulic actuator hydraulic system and hydraulic control system with self-protection function.

[0005] In order to solve the above technical problems, the technical solution provided by the present invention is: an electro-hydraulic actuator hydraulic system, the hydraulic system includes a double-piston rod cylinder, a motor, a hydraulic gear pump, an oil tank, a hydraulic oil circuit and an accumulator, the motor is connected to the hydraulic gear pump, the hydraulic gear pump is connected to the accumulator through a hydraulic oil circuit, a pressure sensor is provided in the hydraulic oil circuit, a breathing valve and a hydraulic oil dipstick are provided on the oil tank, and a liquid level gauge and an oil temperature sensor are provided in the oil tank, an oil drain port is provided at the bottom end of the oil tank, and the hydraulic oil circuit includes a first connecting portion of the accumulator and the hydraulic gear pump The oil circuit and the main oil circuit and return oil pipeline connecting the double-piston rod cylinder and the oil tank, the main oil circuit includes an ESD valve and a shut-off valve arranged in parallel, an open valve is provided on the return oil pipeline, a protection mechanism is provided between the ESD valve, the shut-off valve and the double-piston rod cylinder, a throttling speed regulating valve is provided on the pipeline between the protection mechanism and the double-piston rod cylinder and between the open valve and the double-piston rod cylinder, a pressure gauge and a pressure sensor are connected to the hydraulic oil circuit, a manual pump and a shut-off valve are provided in series in the hydraulic oil circuit, two pressure relief valves are connected in parallel in the hydraulic oil circuit and one of the pressure relief valves is connected in series with the manual pump.

[0006] As an improvement, an oil pressure filter, a one-way oil suction valve and a cut-off ball valve are sequentially provided on the first oil circuit between the oil tank and the accumulator.

[0007] As an improvement, the ESD valve and the shut-off valve are connected in parallel and then connected in series with a hydraulically controlled pilot valve, and the hydraulically controlled pilot valve is a hydraulically controlled two-position three-way valve.

[0008] As an improvement, the motor has a built-in PTC.

[0009] As an improvement, the closing valve and the opening valve adopt an explosion-proof two-position three-way solenoid valve with a handle, and the ESD valve adopts an explosion-proof two-position three-way solenoid valve.

[0010] As an improvement, the protection mechanism is an 80℃ fusible valve structure, which includes a fusible plug arranged in the pipeline. A pressure reducing valve is provided on the pipeline between the fusible plug and the first oil circuit and is connected to two hydraulically controlled interlocking valves. One of the hydraulically controlled interlocking valves is arranged on the pipeline between the first oil circuit and the throttling speed regulating valve between the protection mechanism and the double-piston rod cylinder, and the other hydraulically controlled interlocking valve is arranged on the pipeline between the hydraulically controlled pilot valve and the throttling speed regulating valve between the protection mechanism and the double-piston rod cylinder.

[0011] A hydraulic control system for an electro-hydraulic actuator, the hydraulic control system comprising an electric control box, the bottom of which is provided with a number of explosion-proof glands, a PLC control module and a function panel in the electric control box, a display screen on the function panel, a valve opening button, a valve closing button, a stop button and a confirmation button in a "straight" shape below the display screen, a fully open position light, a fully closed position light, an ESD light, a PST light, a PST button and an ESD reset button built into the display screen, a main power indicator light, a comprehensive fault alarm light and a remote, stop and on-site three-position selector switch, a main power switch, an emergency stop button on one side of the display screen of the function panel, the remote, stop and on-site three-position selector switch Protective covers are hinged on the selection switch, main power switch and emergency stop button. The PLC control module includes a power module, a communication module and a valve control module. The communication module includes a host computer communication port, a pressure sensor communication port, a valve position sensor communication port, a liquid level gauge communication port, an oil temperature sensor communication port, a valve position open position communication port, a valve position closed position communication port and a PST valve position communication port. The valve control module includes a valve opening control port, a valve closing control port, a valve ESD control port and an ESD emergency stop button connection port. The power module includes a power input interface and a motor output interface. The motor is connected to the motor output interface through a power line.

[0012] The advantages of the present invention compared with the prior art are:

[0013] ① The present invention adopts an integrated, modular and miniaturized design of electromechanical and hydraulic integration, which is easy to realize serialization, simple structure, small size, no need for external oil and gas sources, high reliability, long service life, easy installation and adjustment, small maintenance workload, maintenance-free, and strong adaptability to the use environment;

[0014] ② The present invention has standard analog and pulse signal control modes, is easy to interface with the controller, and can accept control signals from any control system;

[0015] ③ Intelligent design output displacement, which can realize the setting, adjustment and control of parameters such as speed, acceleration and dead zone;

[0016] ④It can realize linear correction, water hammer protection and overload protection of the characteristics of the controlled object; it can automatically monitor, diagnose, alarm and protect the operating status of the actuator; it can communicate with the upper control system to realize intelligent closed-loop control of the controlled object;

[0017] ⑤ Designed with single-acting and double-acting hydraulic cylinders, it can achieve high torque and angular displacement output, 100% on / off two-position control mode, and has various safety mechanisms (fully open, fully closed, and locked position) in the event of power failure;

[0018] ⑥ The optional flow coefficient correction function can effectively change the flow coefficient of the valve or reduce the nonlinear error of the electro-hydraulic actuator;

[0019] ⑦ Explosion-proof EXD IIB T4 and protection area grade IP66; ⑦ The present invention can achieve 80℃ easy melting protection.

[0020] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 It is the hydraulic principle diagram of the present invention.

[0023] Figure 2 This is a hydraulic principle diagram of the valve opening state of the present invention.

[0024] Figure 3It is a hydraulic principle diagram of the valve closing state of the present invention.

[0025] Figure 4 This is the hydraulic principle diagram of the ESD state of the present invention.

[0026] Figure 5 It is a hydraulic principle diagram of the easy-melt valve of the present invention.

[0027] Figure 6 It is a schematic diagram of the connection port of the PLC control module of the present invention.

[0028] Figure 7 It is a control circuit diagram of the present invention.

[0029] Figure 8 This is the wiring diagram of the PLC control module of the present invention.

[0030] Figure 9 This is a connection circuit diagram of the comprehensive fault alarm light of the present invention.

[0031] Figure 10 It is a connection circuit diagram of the emergency stop button of the present invention.

[0032] Figure 11 This is a circuit diagram of the remote, stop and on-site three-position selector switch connection of the present invention.

[0033] Figure 12 It is the valve control circuit diagram of the present invention.

[0034] Figure 13 It is the motor control circuit diagram of the present invention.

[0035] Figure 14 This is the terminal block wiring diagram of the present invention.

[0036] Figure 15 It is a structural schematic diagram of the electric control box of the present invention.

[0037] As shown in the figure: 1. Oil tank; 2. Hydraulic gear pump; 3. Motor; 4. Oil drain port; 5. Liquid level gauge; 6. Oil temperature sensor; 7. Breathing valve; 8. Hydraulic oil dipstick; 9. Oil pressure filter; 10. One-way oil suction valve; 11. Hand pump; 12. Pressure relief valve; 13. Stop valve; 14. Pressure gauge; 15. Pressure sensor; 16. Open valve; 17. Close valve; 18. ESD valve; 19. Hydraulic pilot valve; 20. Shut-off ball valve; 21. Accumulator ; 22. Pressure reducing valve; 23. Fusible plug; 24. Hydraulic control interlock valve; 25. Double-piston rod cylinder; 26. Electric control box; 27. Display screen; 28. Main power indicator light; 29. Comprehensive fault alarm light; 30. Remote, stop and on-site three-position selector switch; 31. Main power switch; 32. Emergency stop button; 33. Explosion-proof cable gland; 34. Valve opening button; 35. Valve closing button; 36. Stop button; 37. Confirm button; 38. Throttle speed control valve. DETAILED DESCRIPTION

[0038] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0039] The present invention will be described in further detail below in conjunction with the full text.

[0040] Combine Figures 1 to 15 , an electro-hydraulic actuator hydraulic system, the hydraulic system includes a double-piston-rod cylinder 25, a motor 3, a hydraulic gear pump 2, an oil tank 1, a hydraulic oil circuit and an accumulator 21, the motor 3 is connected to the hydraulic gear pump 2, the hydraulic gear pump 2 is connected to the accumulator 21 through a hydraulic oil circuit, a pressure sensor is provided in the hydraulic oil circuit, a breathing valve 7 and a hydraulic oil dipstick 8 are provided on the oil tank 1, and a liquid level gauge 5 and an oil temperature sensor 6 are provided in the oil tank 1, and an oil drain port 4 is provided at the bottom end of the oil tank 1, the hydraulic oil circuit includes a first oil circuit connecting the accumulator 21 and the hydraulic gear pump 2 and a main oil circuit and a return oil pipeline connecting the double-piston-rod cylinder 25 and the oil tank 1, the main oil circuit includes an ESD valve 18 and a shut-off valve 17 arranged in parallel, an opening valve 16 is provided on the return oil pipeline, and there is a valve between the ESD valve 18, the shut-off valve 17 and the double-piston-rod cylinder 25 Protection mechanism, a throttling speed regulating valve 38 is respectively provided on the pipeline between the protection mechanism and the double-piston rod cylinder 25 and between the opening valve 16 and the double-piston rod cylinder 25, a pressure gauge 14 and a pressure sensor 15 are connected to the hydraulic oil circuit, a manual pump 11 and a shut-off valve 13 are provided in series in the hydraulic oil circuit, two pressure relief valves 12 are connected in parallel in the hydraulic oil circuit and one of the pressure relief valves 12 is connected in series with the manual pump 11, and a pressure oil filter 9, a one-way oil suction valve 10 and a shut-off ball valve 20 are provided in sequence between the oil tank 1 and the accumulator 21 on the first oil circuit, the ESD valve 18 and the closing valve 17 are connected in parallel and then connected in series with a hydraulically controlled pilot valve 19, the hydraulically controlled pilot valve 19 adopts a hydraulically controlled two-position three-way valve, the motor 3 has a built-in PTC, the closing valve 17 and the opening valve 16 adopt an explosion-proof two-position three-way solenoid valve with a handle, and the ESD valve 18 adopts an explosion-proof two-position three-way solenoid valve.

[0041] The protection mechanism is an 80℃ fusible valve structure, which includes a fusible plug 23 arranged in the pipeline. A pressure reducing valve 22 is provided on the pipeline between the fusible plug 23 and the first oil circuit and is connected to two hydraulically controlled interlocking valves 24. One of the hydraulically controlled interlocking valves 24 is arranged on the pipeline between the first oil circuit and the throttling speed regulating valve 38 between the protection mechanism and the double-piston rod cylinder 25, and the other hydraulically controlled interlocking valve 24 is arranged on the pipeline between the hydraulically controlled pilot valve 19 and the throttling speed regulating valve 38 between the protection mechanism and the double-piston rod cylinder 25.

[0042] A hydraulic control system for an electro-hydraulic actuator, the hydraulic control system comprising an electric control box 26, the bottom of which is provided with a plurality of explosion-proof glands 33, the electric control box 26 being provided with a PLC control module and a function panel, the function panel being provided with a display screen 27, the lower portion of the display screen 27 being provided with a valve opening button 34, a valve closing button 35, a stop button 36 and a confirmation button 37 in a "straight" shape, the display screen 27 having built-in full-open position lights, full-close position lights, an ESD light, a PST light, a PST button and an ESD reset button, the function panel being provided with a main power indicator light 28, a comprehensive fault alarm light 29 and a remote, stop and on-site three-position selector switch 30, a main power switch 31, an emergency stop button 32 on one side of the display screen 27 , a protective cover is hinged on the remote, stop and on-site three-position selection switch 30, the main power switch 31, and the emergency stop button 32. The PLC control module includes a power module, a communication module and a valve control module. The communication module includes a host computer communication port, a pressure sensor communication port, a valve position sensor communication port, a liquid level gauge communication port, an oil temperature sensor communication port, a valve position open position communication port, a valve position closed position communication port and a PST valve position communication port. The valve control module includes a valve opening control port, a valve closing control port, a valve ESD control port and an ESD emergency stop button connection port. The power module includes a power input interface and a motor output interface. The motor 3 is connected to the motor output interface through a power line.

[0043] Example

[0044] The present invention is an independently working switch type intelligent electro-hydraulic actuator system for valves, which is used for switching control of angular stroke valves.

[0045] Valve opening process: A valve opening signal is sent remotely or locally, the valve opening 16, i.e., the solenoid valve (OPEN), is energized, the hydraulic system forms a valve opening circuit, and the electro-hydraulic actuator rotates under the drive of the hydraulic oil, driving the valve stem to make an angular stroke displacement, thereby opening the valve;

[0046] Valve closing process: A valve closing signal is sent remotely or locally, the closing valve 17, i.e., the solenoid valve (CLOSE), is energized, the hydraulic system forms a valve closing circuit, and the electro-hydraulic actuator rotates under the drive of the hydraulic oil, driving the valve stem to make an angular stroke displacement, thereby closing the valve;

[0047] ESD valve closing process: When an ESD valve closing signal is sent remotely, the ESD valve 18, i.e., the solenoid valve (ESD), is energized, pushing the hydraulic pilot valve 22 to actuate, forming a valve closing circuit. Driven by the hydraulic oil, the electro-hydraulic actuator rotates, driving the valve stem to perform angular displacement, closing the valve. ESD valve closing has the highest priority.

[0048] Manual pressure application process: When the system has no power supply, operate the manual push rod on the solenoid valve to close the cut-off ball valve 20 at the bottom of the accumulator 21, and manually operate the manual pump 11 to apply pressure to the electro-hydraulic actuator;

[0049] On-site manual control of valve opening and closing process: manually move the external push rod of the solenoid valve to control the solenoid valve opening and closing to realize the valve opening and closing action;

[0050] PST stroke test: A stroke test signal is sent remotely or locally, and the system forms a valve closing circuit 17. The valve is closed 15° to 25° until the "stroke test" contact of the mechanical limit switch is closed. The system forms a valve opening circuit 16, that is, the valve is opened to the fully open position after being closed 15° to 25°. The PST function is only used when the valve is in the fully open position.

[0051] The electro-hydraulic actuator uses BRC4000 / BRC8000. The hydraulic system includes motor 3, hydraulic gear pump 2 and oil tank 1. Motor 3 uses a three-phase AC motor. The hydraulic gear pump 2 is driven by motor 3 to store high-pressure oil in accumulator 21. The system has a pressure sensor 15 to monitor the system pressure. The pressure sensor 15 is explosion-proof and sends the system pressure signal to the PLC control module for control. When the pressure of accumulator 21 reaches the high pressure value (HP) of the system set pressure, motor 3 stops. When the pressure of accumulator 21 is lower than the low pressure value (LP) set by the system, motor 3 is started to replenish the pressure of accumulator 21. A zero-leakage one-way valve is used in the system, and the solenoid valve uses Wan dfluh, SUN hydraulic control valves can maintain system pressure for a long time. The oil tank 1 has a capacity of 48L and is welded from 2mm carbon steel plates. The oil tank 1 has a breather valve 7 and is equipped with an oil filter 9, an oil drain port 4, a one-way oil suction valve 10, a liquid level gauge 5, an oil temperature sensor 6 and a hydraulic oil dipstick 8. The motor 3 is ABB: 0.75kW 380V 50Hz 4PB5 (explosion-proof type). The motor 3 has a built-in PTC, and the temperature control signal is sent to the PLC control module to complete the thermal protection control of the motor 3. The accumulator 21 oil pipe is equipped with a shut-off ball valve. When the manual pump 11 is actuated, the switch is closed. The manual pump 11 directly supplies oil pressure to the actuator, driving the actuator to complete the valve switching action.

[0052] A control oil circuit block is installed on the oil tank 1, and the main hydraulic components are installed on the oil circuit block. The oil pressure filter 9 can protect the cleanliness of the hydraulic oil and avoid internal leakage caused by contamination of the hydraulic components. The pressure sensor 15 can protect the entire hydraulic system from overpressure. The pressure relief valve 12 is set according to the system working pressure. The pressure gauge 14 displays the system working pressure. The throttling speed regulating valve 38 can adjust the working flow of the system and the travel time of the actuator to meet the requirement that the valve closing speed is 3 times faster than the valve opening speed.

[0053] When the system is working, the hydraulically controlled two-position three-way valve, i.e. the hydraulically controlled pilot valve 19, has a manual reversing function. It is used to handle the situation when the power is off or during on-site operation. When the system needs to switch the valve, this handle can be switched to switch the position of the solenoid valve handle, and the valve can be driven to open / close through the pre-stored pressure in the accumulator 21.

[0054] Two explosion-proof two-position three-way solenoid valves (with handles) are used as opening valve 16 and closing valve 17, which are used for switching when the system is working normally, with a low power of 10W.

[0055] An explosion-proof two-position three-way solenoid valve, namely ESD valve 18, is used for ESD. Under normal working conditions, this solenoid valve is in a normally energized state. When energized, the ESD control valve is closed, and the ESD action solenoid valve has the highest priority level and a low power of 10W.

[0056] When the manual pump 11 needs to be operated, the hydraulically controlled pilot valve 19 can be used for manual switching operation, and the handle provided with the system can be used for operation to add hydraulic oil to the electro-hydraulic actuator to drive the valve. The manual pump 11 can be operated to add oil and pressure to the accumulator 21, or to close the shut-off ball valve 20 on the accumulator 21 pipeline to add oil and pressure to the electro-hydraulic actuator.

[0057] When a fire or other abnormal temperature rise accident occurs in the system, when the system temperature reaches 80℃±2℃, the tin-based alloy in the fusible plug melts. Under the impact of the system working pressure, the tin-based alloy flows with the oil, the flow channel is opened, and the pressure reducing valve 22 is opened to form a valve closing circuit. The accumulator 21 drives the electro-hydraulic actuator to close the valve. When the fusible plug takes effect, the tin-based alloy will be retained in the fusible plug valve block, causing the blockage to lose its function. A new fusible plug valve block needs to be replaced before the system can work normally.

[0058] The system uses an independent flameproof electric control cabinet for on-site control. The electric control box 26 is a standard flameproof box, and the valve position feedback switch box is WESTLOCK.

[0059] Electric control box 26 input:

[0060] Power supply: 380VAC / 3PH / 50Hz;

[0061] Remote valve opening / closing command: valve opening when the signal is held (Hold on) / valve closing when the signal is disconnected (Cut Off), active signal (jog hold);

[0062] ESD command: Passive signal, when the signal is held (Hold on), the valve is opened; when the signal is disconnected (Cut Off), the valve is closed. After executing the ESD action, the ESD reset button must be pressed on site to resume remote switch operation;

[0063] On-site valve opening / closing command: long press for three seconds, the valve opens when the signal is held (Hold on) and closes when the signal is disconnected (CutOff), with active signal (jog hold); when the signal is less than three seconds, the valve moves once per click (jog non-hold);

[0064] PST stroke test control command: Regular partial stroke test can prevent the valve from being in the fully open state for a long time and unable to close.

[0065] Electric control box 26 output:

[0066] local / remote signal;

[0067] Open in position signal;

[0068] Close position signal;

[0069] ESD reset output signal;

[0070] Voltage fault signal;

[0071] Liquid level fault signal;

[0072] Pump timeout fault signal.

[0073] Signal failure alarm: When the electro-hydraulic actuator is in remote control mode, the control signal is disconnected, the actuator is locked in place, and a "control signal failure" alarm is issued. When the control signal is restored, the alarm disappears and the actuator resumes adjustment tracking.

[0074] Valve position sensor alarm: disconnect the valve position sensor cable, the actuator will issue a "valve position sensor failure" alarm, the cable is restored, the alarm disappears, and the actuator returns to working mode;

[0075] Motor failure alarm: When the motor driver cable is disconnected, the actuator issues a "motor failure" alarm. After the cable is restored and the driver is powered on again, the actuator resumes working mode.

[0076] Blockage fault alarm: When the electro-hydraulic actuator starts running and the output shaft (rod) of the electro-hydraulic actuator cannot move, the electro-hydraulic actuator will issue a "valve blockage fault" alarm. At this time, press the "Stop" button and the electro-hydraulic actuator will resume working.

[0077] System Operation

[0078] On-site manual oil pump operation: ① Cut off the power supply on site; ② Manually operate the reversing valve; ③ Manually pump until the mechanical indication is in place.

[0079] On-site control switch operation: ① When the system is powered on, the three-position selector switch is set to the reset state (STOP); ② "On-site" is selected, and on-site control takes priority; ③ "Open valve" or "Close valve" is pressed, and the button is self-holding; ④ The solenoid valve works in reverse until it is "fully open" or "fully closed", and the solenoid valve is reset; ⑤ Press the "Stop" button, and the solenoid valve returns to the fully locked position; ⑥ The "fully open" or "fully closed" light is displayed; ⑦ It does not work when the system is in alarm state.

[0080] Remote control operation: ① System power on, three-position selector switch set to reset state (STOP); ② System ESD signal maintained; ③ "Remote" selected; ④ "On" or "Off" signal maintained; ⑤ Emergency stop button enabled.

[0081] ESD operation: ① When the system is powered on, the ESD signal is disconnected, the solenoid valve is reversed, and the electro-hydraulic actuator is activated; ② The priority level overrides valve opening, valve closing, and PST control; ③ After ESD is activated, the system is locked and remote operation is not allowed. Remote control can only be restored after pressing the ESD reset button on site.

[0082] PST operation: ① System power-on, "remote" or "on-site" status; ② PST is only valid when the valve is in the open position; ③ After the PST button is activated, the actuator moves in the valve closing direction until it reaches the preset PST position of 15°~25° (20%±10% of the angular travel), the contact switch closes, the solenoid valve changes direction, and the actuator works in the reverse direction (valve opening direction) until it returns to the "fully open" state.

[0083] Switching speed adjustment: The valve switching time can be adjusted by the throttling speed regulating valve 38, and the valve closing time can be adjusted to 1 / 3 of the valve opening time.

[0084] PLC reset operation: When a system failure or alarm occurs, you can use the three-position selector switch to reset the PLC system. Set the three-position selector switch to the middle position of "Stop" and then switch to the "On-site" or "Remote" state.

[0085] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.

Claims

1. An electro-hydraulic actuator hydraulic system, characterized in that: The hydraulic system comprises a double-piston rod cylinder (25), a motor (3), a hydraulic gear pump (2), an oil tank (1), a hydraulic oil circuit and an accumulator (21), wherein the motor (3) is connected to the hydraulic gear pump (2), and the hydraulic gear pump (2) is connected to the accumulator (21) via a hydraulic oil circuit, wherein a pressure sensor is provided in the hydraulic oil circuit, a breathing valve (7) and a hydraulic oil dipstick (8) are provided on the oil tank (1), and a liquid level gauge (5) and an oil temperature sensor (6) are provided in the oil tank (1), and an oil discharge port (4) is provided at the bottom end of the oil tank (1), and the hydraulic oil circuit comprises a first oil circuit connecting the accumulator (21) and the hydraulic gear pump (2) and a second oil circuit connecting the double-piston rod cylinder (25) and the oil tank (1). A main oil circuit and a return oil pipeline, wherein the main oil circuit includes an ESD valve (18) and a shutoff valve (17) arranged in parallel, an opening valve (16) is provided on the return oil pipeline, a protection mechanism is provided between the ESD valve (18), the shutoff valve (17) and the double-piston rod cylinder (25), a throttling speed regulating valve (38) is provided on the pipeline between the protection mechanism and the double-piston rod cylinder (25) and between the opening valve (16) and the double-piston rod cylinder (25), a pressure gauge (14) and a pressure sensor (15) are connected to the hydraulic oil circuit, a manual pump (11) and a shutoff valve (13) are provided in series in the hydraulic oil circuit, and two pressure relief valves (12) are connected in parallel in the hydraulic oil circuit, and one of the pressure relief valves (12) is connected in series with the manual pump (11); The protection mechanism is an 80°C fusible valve structure, which includes a fusible plug (23) arranged in a pipeline. A pressure reducing valve (22) is provided on the pipeline between the fusible plug (23) and the first oil circuit and is connected to two hydraulically controlled interlocking valves (24), one of which is arranged on the pipeline between the first oil circuit and the throttle speed regulating valve (38) between the protection mechanism and the double-piston rod cylinder (25), and the other hydraulically controlled interlocking valve (24) is arranged on the pipeline between the hydraulically controlled pilot valve (19) and the throttle speed regulating valve (38) between the protection mechanism and the double-piston rod cylinder (25).

2. The electro-hydraulic actuator hydraulic system according to claim 1, characterized in that: The first oil circuit is provided with an oil pressure filter (9), a one-way oil suction valve (10) and a cut-off ball valve (20) in sequence between the oil tank (1) and the accumulator (21).

3. The electro-hydraulic actuator hydraulic system according to claim 1, characterized in that: The ESD valve (18) and the shut-off valve (17) are connected in parallel and then connected in series with a hydraulically controlled pilot valve (19), wherein the hydraulically controlled pilot valve (19) is a hydraulically controlled two-position three-way valve.

4. The electro-hydraulic actuator hydraulic system according to claim 1, characterized in that: The motor (3) has a built-in PTC.

5. The electro-hydraulic actuator hydraulic system according to claim 1, characterized in that: The closing valve (17) and the opening valve (16) adopt explosion-proof two-position three-way solenoid valves with handles, and the ESD valve (18) adopts an explosion-proof two-position three-way solenoid valve.

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