A high-low pressure isolated electro-hydraulic servo and a working method thereof

Abstract

The application relates to a high-low pressure isolation type electro-hydraulic steering engine and a working method thereof, and belongs to the technical field of hydraulic transmission, which solves the problems of instant high pressure damage to hydraulic components and high cost in the prior art. The application comprises a power unit, a pressure maintaining and oil supplementing unit, a mode circuit, a protection circuit, an isolation circuit and an executing component, the executing component is used for driving a load, the isolation circuit is used for isolating high and low pressures of the electro-hydraulic steering engine, the protection circuit is used for ensuring that the executing component is not damaged when the executing component encounters abnormally high pressure, the mode selection circuit is used for selecting a working mode of the electro-hydraulic steering engine, the pressure maintaining and oil supplementing unit is used for filtering, supplementing oil and overpressure protection of an oil circuit, and the power unit is used for providing power for the electro-hydraulic steering engine. The application is provided with the isolation circuit, thereby avoiding the adverse effects of instant high pressure on the electro-hydraulic steering engine, and saving the cost.

Description

Technical Field

[0001] This invention relates to the field of hydraulic transmission technology, and in particular to a high-low pressure isolated electro-hydraulic steering gear and its working method. Background Technology

[0002] With the development of power transmission technology, electro-hydraulic servo motors have been widely used in aerospace and other fields. When a large impact occurs at the load end of an electro-hydraulic servo motor, a high instantaneous pressure will be generated in the hydraulic lines, damaging the hydraulic components inside the servo motor. Currently, there is no effective method to reduce or avoid the impact of the instantaneous high pressure caused by the impact on the system.

[0003] In addition, existing electro-hydraulic steering gears use internal ultra-high pressure resistant components to withstand external high pressure, which is costly. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a high-low pressure isolated electro-hydraulic servo motor and its working method, in order to solve the problems of instantaneous high pressure damage to hydraulic components and high cost of existing electro-hydraulic servo motors.

[0005] On one hand, the present invention provides a high-low pressure isolated electro-hydraulic servo motor, including a power unit, a pressure-maintaining and oil-replenishing unit, a mode circuit, a protection circuit, an isolation circuit, and an actuator connected to each other. The actuator is used to drive the load, the isolation circuit is used to isolate the high and low pressures of the electro-hydraulic servo motor, the protection circuit is used to ensure that the actuator is not damaged when it encounters abnormal high pressure, the mode selection circuit is used to select the working mode of the electro-hydraulic servo motor, the pressure-maintaining and oil-replenishing unit is used to filter, replenish, and protect the oil circuit from overpressure, and the power unit is used to provide power to the electro-hydraulic servo motor.

[0006] Furthermore, the actuating element includes a single-rod hydraulic cylinder and a position sensor, the position sensor being used to monitor the position of the piston rod of the hydraulic cylinder.

[0007] Furthermore, the hydraulic cylinder is divided into a rod chamber and a rodless chamber, and the isolation circuit connects the rod chamber and the rodless chamber.

[0008] Furthermore, the isolation circuit includes a first cylinder safety valve and a second cylinder safety valve, which are connected in parallel between the oil passages connecting the rod chamber and the rodless chamber.

[0009] Furthermore, the isolation circuit also includes a first lock-up valve and a second lock-up valve, which are respectively located on the oil lines connecting the rodless chamber and the rod chamber.

[0010] Furthermore, the protection circuit includes a first relief valve and a second relief valve, which are connected in parallel between the oil passages connecting the rod chamber and the rodless chamber.

[0011] Furthermore, the protection circuit also includes a first pressure sensor and a second pressure sensor, which are respectively located in the oil lines connected to the rodless chamber and the rod chamber.

[0012] Furthermore, the mode selection circuit includes a solenoid valve and is connected in parallel between the oil passages connecting the rod chamber and the rodless chamber.

[0013] Furthermore, the pressure-maintaining and oil-replenishing unit includes a first check valve and a second check valve, which are connected in series and then in parallel between the oil circuits connecting the rod chamber and the rodless chamber.

[0014] On the other hand, the present invention provides a method for operating a high-low voltage isolated electro-hydraulic servo motor, the steps of which include:

[0015] Step 1: Connect the load to the actuator;

[0016] Step 2: The solenoid valve is energized, the motor runs and drives the hydraulic pump to inject hydraulic oil into the rodless chamber, which in turn drives the load to do work;

[0017] Step 3: Compare the hydraulic pressure in the hydraulic line with the set pressure value of the relief valve. If the hydraulic pressure is greater than the set pressure of the relief valve, the relief valve will overflow to protect the actuator. If it is not greater, proceed to step 4.

[0018] Step 4: Determine the magnitude of the impact at the load end. When there is a large impact at the load end, the electro-hydraulic servo motor rotates to relieve pressure. At the same time, the isolation circuit protects the entire electro-hydraulic servo motor under instantaneous high pressure. The load executes steps 2 to 3.

[0019] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0020] (1) The high and low pressure isolated electro-hydraulic servo motor of the present invention is equipped with an isolation circuit, which effectively avoids the adverse effects of instantaneous high pressure caused by load impact on other components of the electro-hydraulic servo motor. When there is a large load impact, the two lock-up valves are energized to isolate the high and low pressure circuit oil. The high pressure oil is converted into the linear motion of the cylinder through the two cylinder safety valves to unload, effectively realizing the protection of other components.

[0021] (2) The high and low pressure isolated electro-hydraulic steering gear of the present invention is equipped with an isolation circuit. It is only necessary to design the two lock-up valves, the two cylinder safety valves, the actuators and the hydraulic pipelines therebetween to be high pressure resistant. There is no need to select other components as high-cost ultra-high pressure resistant components, which effectively saves costs.

[0022] (3) The high-low pressure isolated electro-hydraulic servo motor of the present invention can automatically enter the isolation state before a large impact load occurs. When the electro-hydraulic servo motor is in the normal servo operation state, the two lock-up valves are in the open non-isolated state, and the oil in the two chambers of the servo hydraulic cylinder passes smoothly through the two lock-up valves, and the system pressure is in the normal medium-high pressure range; when the electro-hydraulic servo motor reaches the command requirement range, the two lock-up valves are in the closed isolation state, and the oil in the two chambers of the servo hydraulic cylinder is cut off by the two lock-up valves, and the system pressure is in the normal medium-high pressure range.

[0023] (4) The high and low pressure electro-hydraulic steering gear of the present invention uses a high pressure resistant locking valve to isolate the high and low pressure chambers of the electro-hydraulic steering gear, which protects the internal components of the electro-hydraulic steering gear at a lower cost; at the same time, the controller assembly and actuator assembly of the electro-hydraulic steering gear are integrated into a compact structure and save space.

[0024] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0026] Figure 1 This is a schematic diagram of a high- and low-pressure isolated electro-hydraulic servo actuator assembly according to a specific embodiment;

[0027] Figure 2 This is a schematic diagram of the power source composition in a specific embodiment;

[0028] Figure 3 This is a schematic diagram of the pressure-holding and oil-replenishing circuit in a specific embodiment;

[0029] Figure 4 A schematic diagram of the composition of the mode selection loop in a specific embodiment;

[0030] Figure 5 This is a schematic diagram of the protection circuit composition in a specific embodiment;

[0031] Figure 6 This is a schematic diagram of the isolation circuit composition in a specific embodiment;

[0032] Figure 7 This is a schematic diagram of the composition of the execution element in a specific embodiment.

[0033] Figure label:

[0034] 1-Power unit; 11-Motor; 12-Hydraulic pump; 13-Motor speed sensor; 2-Pressure holding and oil replenishment unit; 21-Boosting oil tank; 22-First check valve; 23-Second check valve; 24-Boosting oil tank pressure sensor; 3-Mode circuit; 31-Solenoid valve; 4-Protection circuit; 41-First relief valve; 42-Second relief valve; 43-First pressure sensor; 44-Second pressure sensor; 5-Isolation circuit; 51-First cylinder safety valve; 52-Second cylinder safety valve; 53-First locking valve; 54-Second locking valve; 6-Actuator; 61-Hydraulic cylinder; 62-Position sensor. Detailed Implementation

[0035] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connected" should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0037] Throughout the text, the terms “top,” “bottom,” “above,” “below,” and “on top” refer to the relative positions of components of the device, such as the relative positions of the top and bottom substrates within the device. It is understood that the device is multifunctional and independent of its spatial orientation.

[0038] Example 1

[0039] A specific embodiment of the present invention, such as Figures 1-7 As shown, a high-low pressure isolated electro-hydraulic servo motor is disclosed, including a power unit 1, a pressure maintaining and oil replenishing unit 2, a mode circuit 3, a protection circuit 4, an isolation circuit 5, and an actuator 6 that are interconnected.

[0040] Compared with the prior art, the high and low pressure isolated electro-hydraulic servo motor provided in this embodiment is equipped with an isolation circuit, which effectively avoids the adverse effects of instantaneous high pressure caused by load impact on other components of the electro-hydraulic servo motor. When there is a large load impact, the two lock-up valves are energized to isolate the high and low pressure circuit oil. The high pressure oil is converted into the linear motion of the cylinder through the two cylinder safety valves to unload, effectively protecting other components.

[0041] The actuator 6 is used to drive the load, including a single-rod hydraulic cylinder 61 and a position sensor 62. The position sensor 62 is used to monitor the position of the piston rod of the hydraulic cylinder 61, which can realize basic control of the thrust and movement position of the hydraulic cylinder 61.

[0042] The hydraulic cylinder 61 is divided into a rod chamber and a rodless chamber, and the isolation circuit 5 connects the rod chamber and the rodless chamber of the hydraulic cylinder 61.

[0043] The isolation circuit 5 includes a first cylinder safety valve 51, a second cylinder safety valve 52, a first locking valve 53, and a second locking valve 54. The first cylinder safety valve 51 and the second cylinder safety valve 52 are connected in parallel between the oil lines connecting the rod chamber and the rodless chamber of the hydraulic cylinder 61. The first locking valve 53 and the second locking valve 54 are respectively located on the oil lines connecting the rodless chamber and the rod chamber of the hydraulic cylinder 61.

[0044] In this embodiment, the isolation circuit 5 includes two cylinder safety valves (first cylinder safety valve 51 and second cylinder safety valve 52) and two lock-up valves (first lock-up valve 53 and second lock-up valve 54), which are installed near the actuator 6 to isolate the high and low pressure of the electro-hydraulic servo motor.

[0045] When both locking valves are de-energized, the inlet and outlet ports of the locking valves are in a bidirectional flow state, which is used for the no-load impact working mode. When both locking valves are energized, the inlet and outlet ports of the locking valves are in a unidirectional flow state, which is used for the load impact working mode. When the pressure in the cylinder is higher than the set pressure of the cylinder safety valve, the cylinder safety valve overflows, and the high-pressure oil in the hydraulic cylinder is unloaded through the two cylinder safety valves.

[0046] The protection circuit 4 is used to ensure that the actuator 6 is not damaged when it encounters abnormal high voltage.

[0047] Specifically, the protection circuit 4 includes a first relief valve 41, a second relief valve 42, a first pressure sensor 43, and a second pressure sensor 44. The first relief valve 41 and the second relief valve 42 are connected in parallel between the oil lines connecting the rod chamber and the rodless chamber of the hydraulic cylinder 61. The first pressure sensor 43 and the second pressure sensor 44 are respectively located in the oil lines connecting the rodless chamber and the rod chamber of the hydraulic cylinder 61 to monitor the pressure in the rod chamber and the rodless chamber of the hydraulic cylinder 61.

[0048] In this embodiment, two relief valves (first relief valve 41 and second relief valve 42) are installed near the actuator 6. Before the hydraulic transmission device operates, a relief pressure is set. When the oil pressure in the pipeline is higher than the set pressure of the relief valve, the relief valve overflows to protect the actuator 6 from pressure. Pressure sensors (first pressure sensor 43 and second pressure sensor 44) are installed near the actuator 6 to monitor the pressure changes of the actuator 6 in real time.

[0049] The mode selection circuit 3 is used to select the operating mode of the electro-hydraulic servo motor, namely the loaded mode and the unloaded mode. The operating mode of the electro-hydraulic servo motor is selected by switching the valve core position of the solenoid valve 31.

[0050] When solenoid valve 31 is energized, the inlet and outlet ports are closed, and the electro-hydraulic servo motor is in the load-bearing mode. The oil in hydraulic pump 12 reaches the actuator 6 through the hydraulic pipeline to perform work on the load. When solenoid valve 31 is de-energized, the inlet and outlet ports of solenoid valve are open, and the electro-hydraulic servo motor is in the unloading mode. The oil at the outlet of hydraulic pump 12 reaches the inlet port through solenoid valve 31.

[0051] In this embodiment, the mode selection circuit 3 is connected in parallel between the oil circuits connecting the rod chamber and the rodless chamber of the hydraulic cylinder 61.

[0052] The pressure-maintaining and oil-replenishing unit 2 is used to filter, replenish, and protect the oil circuit from overpressure without changing the flow direction of the oil.

[0053] Specifically, the pressure-maintaining and oil-replenishing unit 2 includes a booster oil tank 21, a first check valve 22, a second check valve 23, and a booster oil tank pressure sensor 24. The first check valve 22 and the second check valve 23 are connected in series and then in parallel between the oil circuits connecting the rod chamber and the rodless chamber of the hydraulic cylinder 61. The booster oil tank 21 is connected between the first check valve 22 and the second check valve 23 through a pipeline. The booster oil tank pressure sensor 24 is located on the oil circuit of the booster oil tank 21.

[0054] In this embodiment, the pressure-maintaining and oil-replenishing unit 2 includes a booster tank 21, two check valves (a first check valve 22 and a second check valve 23), and a booster tank pressure sensor 24, which are used for filtering, replenishing oil, and protecting the oil circuit from overpressure. When the oil pressure in the pipeline is too low, the booster tank 21 replenishes oil and pressurizes the hydraulic circuit through the check valves.

[0055] The power unit 1 provides power to the electro-hydraulic steering gear and includes a motor 11, a hydraulic pump 12, and a motor speed sensor 13. The motor speed sensor 13 is mounted on the motor 11. The hydraulic pump 12 is connected to the actuator 6 via a hydraulic circuit. Specifically, the hydraulic pump 12 is connected to the rod chamber and the rodless chamber of the hydraulic cylinder 61 via hydraulic lines.

[0056] In this embodiment, motor 11 is a DC brushless permanent magnet motor, hydraulic pump 12 is a plunger pump, and motor speed sensor 13 is a Hall sensor or a rotary transformer.

[0057] The working process of the high-low pressure isolated electro-hydraulic servo motor in this embodiment is as follows: When the solenoid valve 31 is energized, the inlet and outlet oil ports are closed, and the electro-hydraulic servo motor is in load mode. A high-speed operation command is sent to the servo motor 11, and the hydraulic pump 12 rotates at high speed with the servo motor. The oil flows through the safety circuit 2, the protection circuit 4, and the isolation circuit 5, and outputs a large flow rate to the rodless chamber of the single-rod hydraulic cylinder 61. The piston rod of the single-rod hydraulic cylinder 61 extends rapidly, driving the load to do work. If the hydraulic pressure in the hydraulic line is high, exceeding the set pressure of the relief valve, the relief valve overflows, providing pressure protection for the actuator 6. When there is a large impact at the load end, the solenoid valve 31 is de-energized, and the inlet and outlet ports of the solenoid valve 31 are open, putting the electro-hydraulic servo motor in unloading mode. The hydraulic pump 12 runs at high speed with the servo motor, and the oil flows through the safety circuit 2 and the mode selection circuit 3, without performing work on the load. At the same time, when the two lockout valves are energized, the inlet and outlet ports of the lockout valves are in a one-way open state. When the pressure in the cylinder is higher than the set pressure of the cylinder safety valve, the cylinder safety valve overflows, and the high-pressure oil in the hydraulic cylinder is unloaded through the two cylinder safety valves, achieving protection for the entire electro-hydraulic servo motor under instantaneous high pressure.

[0058] The high- and low-voltage isolated electro-hydraulic servo motor also includes a control component, which consists of a controller and a motor driver. The controller uses a DSP as the main control chip and contains an AD acquisition module, PWM output, communication module, etc. The motor driver is a three-phase bridge circuit of a brushless permanent magnet motor, which includes protection circuit and current sensor.

[0059] It should be noted that the power unit 1, pressure maintaining and oil replenishing unit 2, mode selection circuit 3, protection circuit 4, isolation circuit 5, actuator 6, and matching hydraulic pipelines constitute the actuator assembly of the high-low pressure isolated electro-hydraulic steering gear. The control assembly is used to control the movement of the actuator assembly.

[0060] Example 2

[0061] A specific embodiment of the present invention discloses a method for operating a high-low voltage isolated electro-hydraulic servo motor, the steps of which include:

[0062] Step 1: Connect the load to the actuator 6;

[0063] Step 2: When the solenoid valve 31 is energized, the motor 11 runs and drives the hydraulic pump 12 to run, injecting hydraulic oil into the rodless chamber and driving the load to do work.

[0064] Specifically, when the solenoid valve 31 is energized, the inlet and outlet oil ports are closed, and the electro-hydraulic servo motor is in load mode. A high-speed operation command is sent to the servo motor 11, and the hydraulic pump 12 rotates at high speed with the servo motor. The oil flows through the safety circuit 2, the protection circuit 4, and the isolation circuit 5, and outputs a large flow rate to the rodless chamber of the single-rod hydraulic cylinder 61. The piston rod of the single-rod hydraulic cylinder 61 extends rapidly, driving the load to do work.

[0065] Step 3: Compare the oil pressure in the hydraulic line with the set pressure value of the relief valve. If the oil pressure is greater than the set pressure of the relief valve, the relief valve will overflow, and pressure protection will be provided for the actuator 6. If it is not greater than the set pressure, proceed to step 4.

[0066] Step 4: Determine the magnitude of the impact at the load end. When a large impact occurs at the load end, the electro-hydraulic servo motor rotates to relieve pressure. Simultaneously, isolation circuit 5 protects the entire electro-hydraulic servo motor under instantaneous high pressure. The load then executes steps 2 and 3. It should be noted that an impact at the load end greater than 40 MPa is defined as a large impact.

[0067] Specifically, when there is a large impact on the load end, the solenoid valve 31 is de-energized, the oil inlet and outlet of the solenoid valve 31 are connected, the electro-hydraulic servo motor is in unloading mode, the hydraulic pump 12 runs at high speed with the servo motor, and the oil flows through the safety circuit 2 and the mode selection circuit 3, without doing work on the load; at the same time, when the two lock-up valves are energized, the oil inlet and outlet of the lock-up valves are in a one-way connected state. When the pressure in the cylinder is higher than the set pressure of the cylinder safety valve, the cylinder safety valve overflows, and the high-pressure oil in the hydraulic cylinder is unloaded through the two cylinder safety valves, realizing the protection of the entire electro-hydraulic servo motor under instantaneous high pressure.

[0068] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0069] (1) The high and low pressure isolated electro-hydraulic servo motor of the present invention is equipped with an isolation circuit, which effectively avoids the adverse effects of instantaneous high pressure caused by load impact on other components of the electro-hydraulic servo motor. When there is a large load impact, the two lock-up valves are energized to isolate the high and low pressure circuit oil. The high pressure oil is converted into the linear motion of the cylinder through the two cylinder safety valves to unload, effectively realizing the protection of other components.

[0070] (2) The high and low pressure isolated electro-hydraulic steering gear of the present invention is equipped with an isolation circuit. It is only necessary to design the two lock-up valves, the two cylinder safety valves, the actuators and the hydraulic pipelines therebetween to be high pressure resistant. There is no need to select other components as high-cost ultra-high pressure resistant components, which effectively saves costs.

[0071] (3) The high-low pressure isolated electro-hydraulic servo motor of the present invention can automatically enter the isolation state before a large impact load occurs. When the electro-hydraulic servo motor is in the normal servo operation state, the two lock-up valves are in the open non-isolated state, and the oil in the two chambers of the servo hydraulic cylinder passes smoothly through the two lock-up valves, and the system pressure is in the normal medium-high pressure range; when the electro-hydraulic servo motor reaches the command requirement range, the two lock-up valves are in the closed isolation state, and the oil in the two chambers of the servo hydraulic cylinder is cut off by the two lock-up valves, and the system pressure is in the normal medium-high pressure range.

[0072] (4) The high and low pressure electro-hydraulic steering gear of the present invention uses a high pressure resistant locking valve to isolate the high and low pressure chambers of the electro-hydraulic steering gear, which protects the internal components of the electro-hydraulic steering gear at a lower cost; at the same time, the controller assembly and actuator assembly of the electro-hydraulic steering gear are integrated into a compact structure and save space.

[0073] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-low voltage isolated electro-hydraulic servo motor, characterized in that, The system includes interconnected power units, pressure-maintaining and oil-replenishing units, mode circuits, protection circuits, isolation circuits, and actuators. The actuators drive the load. The isolation circuit isolates the electro-hydraulic servo motor from high and low pressure. The protection circuit prevents damage to the actuators when they encounter abnormally high pressure. The mode selection circuit selects the operating mode of the electro-hydraulic servo motor. The pressure-maintaining and oil-replenishing unit filters, replenishes, and provides overpressure protection for the oil circuit. The power unit provides power to the electro-hydraulic servo motor. The actuators include a single-rod hydraulic cylinder, which is divided into a rod-driven chamber and a non-rod-driven chamber. The rod chamber is connected by an isolation circuit that links the rod chamber and the rodless chamber. The isolation circuit includes a first cylinder safety valve, a second cylinder safety valve, a first locking valve, and a second locking valve. The first and second cylinder safety valves are connected in parallel between the oil lines connecting the rod chamber and the rodless chamber. The first and second locking valves are respectively located on the oil lines connecting the rodless chamber and the rod chamber. When the two first and second locking valves are energized, the high and low pressure oil circuits are isolated, and the high pressure oil is converted into linear motion of the cylinder for unloading through the first and second cylinder safety valves.

2. The high-low voltage isolated electro-hydraulic servo motor according to claim 1, characterized in that, The actuator also includes a position sensor for monitoring the position of the piston rod of the hydraulic cylinder.

3. The high-low voltage isolated electro-hydraulic servo motor according to claim 1, characterized in that, The protection circuit includes a first relief valve and a second relief valve, which are connected in parallel between the oil passages connecting the rod chamber and the rodless chamber.

4. The high-low voltage isolated electro-hydraulic servo motor according to claim 3, characterized in that, The protection circuit also includes a first pressure sensor and a second pressure sensor, which are respectively located on the oil lines connecting the rodless chamber and the rod chamber.

5. The high-low voltage isolated electro-hydraulic servo motor according to claim 1, characterized in that, The mode selection circuit includes a solenoid valve and is connected in parallel between the oil passages connecting the rod chamber and the rodless chamber.

6. The high-low voltage isolated electro-hydraulic servo motor according to claim 1, characterized in that, The pressure-maintaining and oil-replenishing unit includes a first check valve and a second check valve, which are connected in series and then in parallel between the oil circuits connecting the rod chamber and the rodless chamber.

7. A method for operating a high-low voltage isolated electro-hydraulic servo motor according to any one of claims 1-6, characterized in that the steps include... include: Step 1: Connect the load to the actuator; Step 2: The solenoid valve is energized, the motor runs and drives the hydraulic pump to inject hydraulic oil into the rodless chamber, which in turn drives the load to do work; Step 3: Compare the hydraulic pressure in the hydraulic line with the set pressure value of the relief valve. If the hydraulic pressure is greater than the set pressure of the relief valve, the relief valve will overflow to protect the actuator. If it is not greater, proceed to step 4. Step 4: Determine the magnitude of the impact at the load end. When there is a large impact at the load end, the electro-hydraulic servo motor rotates to relieve pressure. At the same time, the isolation circuit protects the entire electro-hydraulic servo motor under instantaneous high pressure. The load executes steps 2 to 3.

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