Anti-load impact electro-hydraulic push rod and mechanical equipment

Abstract

This disclosure relates to an anti-load impact electro-hydraulic actuator and mechanical device. When the three-position four-way solenoid directional valve is in the third position, the first valve body is open, and the relief valve provides a continuous pressure to the rodless chamber. The relief valve will only open when the pressure in the rodless chamber is greater than the preset pressure of the relief valve. When the pressure of the external load on the piston rod is less than the preset pressure of the relief valve, the relief valve provides a continuous and stable pressure to the piston rod and the rodless chamber, so that the hydraulic cylinder maintains a constant clamping force. The relief valve itself has a set pressure value, and it can only open when the external pressure is greater than this pressure value. Therefore, when the external impact is less than the set pressure value, the relief valve itself will not be open. When the reverse load is large and exceeds the set pressure value of the relief valve, the rodless chamber is in a high-pressure state, the relief valve opens, and the rodless chamber starts to unload oil, thereby releasing the instantaneous high pressure generated by the impact and protecting the pipeline and seals.

Description

Technical Field

[0001] This disclosure relates to the field of electric linear actuator technology, and more specifically, to a load-impact resistant electro-hydraulic linear actuator and mechanical device. Background Technology

[0002] An electro-hydraulic linear actuator, or simply electro-hydraulic actuator, is a linear drive device that integrates mechanics, electricity, and hydraulics. It integrates a motor, hydraulic system, and cylinder, and can output large thrust and perform reciprocating linear motion.

[0003] In hydraulic systems of construction machinery, actuators often need to operate under stable pressure; therefore, a separate pressure-holding function is required in electro-hydraulic actuators. Existing technology provides a pressure-holding system, such as... Figure 1 As shown, when the load on the rod chamber 1' is large, the pressure in the rodless chamber 2' increases. When the pressure exceeds the pressure set by the sequence valve 5', the sequence valve 5' is opened, and the two-position three-way hydraulic control directional valve 4' is switched under the action of the hydraulic control end pressure oil. The hydraulic oil output by the hydraulic pump flows into the rodless chamber 2' through the two-position three-way hydraulic control directional valve 4' and the check valve 3' to achieve pressure maintenance.

[0004] However, existing solutions cannot cope with the impact of drastic load changes. Summary of the Invention

[0005] This disclosure addresses the aforementioned technical problems by designing an anti-load impact electro-hydraulic actuator.

[0006] A brief overview of this disclosure will be given below to provide a basic understanding of certain aspects of it. It should be understood that this overview is not an exhaustive summary of this disclosure. It is not intended to identify key or essential parts of this disclosure, nor is it intended to limit the scope of this disclosure. Its purpose is merely to present certain concepts in a simplified form as a prelude to the more detailed description that follows.

[0007] According to the present disclosure, an anti-load impact electro-hydraulic actuator includes: a hydraulic valve block, including an oil tank and a hydraulic power pump connected to the oil tank; a hydraulic cylinder, disposed on one side of the hydraulic valve block, including a cylinder body and a piston rod disposed within the cylinder body, the piston rod dividing the cylinder body into a rod-side chamber and a rodless chamber; a main hydraulic circuit, connected to the oil tank, including a first oil passage connecting the rodless chamber and a second oil passage connecting the rod-side chamber; and a three-position four-way solenoid directional valve, disposed on the main hydraulic circuit, having a first position for inleting oil into the rod-side chamber and an oil-inlet position for inleting oil into the rodless chamber. The second position, and the third position to stop oil from entering the rod chamber; the third oil circuit, one end connected to the first oil circuit, and the other end connected to the oil tank; the third oil circuit is provided with a first valve body and an overflow valve, when the three-position four-way solenoid directional valve is in the third position, the first valve body is open, and the overflow valve is used to open when the pressure in the rodless chamber exceeds a preset pressure value; the fourth oil circuit, one end connected to the second oil circuit, and the other end connected to the oil tank; the fourth oil circuit is provided with a second valve body, when the overflow valve is open, the second valve body is open.

[0008] The anti-load impact electro-hydraulic actuator provided by the present invention further includes: a pressure sensor connected to the first oil circuit for real-time monitoring of the pressure in the rodless chamber; the hydraulic power pump and the three-position four-way solenoid valve are respectively communicatively connected to the pressure sensor; when the pressure in the rodless chamber is less than a preset pressure value, the pressure sensor controls the hydraulic power pump to start and controls the three-position four-way solenoid valve to enter the second position.

[0009] The present invention provides an anti-load impact electro-hydraulic actuator, wherein the hydraulic power pump includes a servo motor and a gear pump connected to the servo motor, and the pressure sensor is communicatively connected to the servo motor.

[0010] The anti-load impact electro-hydraulic actuator provided by the present invention has an outer cylinder intermediate connecting seat between the hydraulic valve block and the hydraulic cylinder, and the outer cylinder intermediate connecting seat is provided with a second oil passage.

[0011] The present invention provides an anti-load impact electro-hydraulic actuator, wherein a first hydraulic control check valve is provided in the first oil circuit to control the unidirectional flow of hydraulic oil to the rodless chamber, and a second hydraulic control check valve is provided in the second oil circuit to control the unidirectional flow of hydraulic oil to the rod chamber.

[0012] The anti-load impact electro-hydraulic actuator provided by the present invention has a first hydraulically controlled check valve disposed on the middle connecting seat of the outer cylinder and a second hydraulically controlled check valve disposed on the hydraulic valve block.

[0013] The anti-load impact electro-hydraulic actuator provided by the present invention has a second valve body that is a tubular check valve and a first valve body that is a two-position two-way solenoid valve.

[0014] The anti-load impact electro-hydraulic actuator provided by the present invention also includes a displacement sensor, which is disposed at the top of the hydraulic cylinder to monitor the position of the piston rod itself in real time.

[0015] The anti-load impact electro-hydraulic actuator provided by the present invention has a displacement sensor that is communicatively connected to a hydraulic power pump and a three-position four-way solenoid directional valve, respectively.

[0016] The present invention also provides a mechanical device, including the electro-hydraulic actuator provided by the present invention.

[0017] The technical solution of this invention has the following advantages: 1. The anti-load impact electro-hydraulic actuator provided by the present invention has a three-position four-way solenoid directional valve installed on the main hydraulic circuit. It has a first position for allowing oil to enter the rod chamber, a second position for allowing oil to enter the rodless chamber, and a third position for stopping oil entry into the rod chamber. One end of the third oil circuit is connected to the first oil circuit, and the other end is connected to the oil tank. A first valve body and an overflow valve are installed on the third oil circuit. When the three-position four-way solenoid directional valve is in the third position, the first valve body is open, and the overflow valve is used to open when the pressure in the rodless chamber exceeds a preset pressure value. One end of the fourth oil circuit is connected to the second oil circuit, and the other end is connected to the oil tank. A second valve body is installed on the fourth oil circuit, and the second valve body opens when the overflow valve opens.

[0018] With the above settings, pressure holding operation can be achieved first: when the three-position four-way solenoid directional valve is in the third position, the first valve body is open, and the relief valve will give the rodless chamber a continuous pressure. Only when the pressure in the rodless chamber is greater than the preset pressure of the relief valve will the relief valve open. When the pressure of the external load on the piston rod is less than the preset pressure of the relief valve, the relief valve will give the piston rod and the rodless chamber a continuous and stable pressure, so that the hydraulic cylinder maintains a constant clamping force.

[0019] It can also resist external load impacts: Since the relief valve itself has a set pressure value, it can only open when the external pressure is greater than the set pressure value. Therefore, when the external impact is less than the set pressure value, the relief valve itself will not conduct. When the reverse load is large and exceeds the set pressure value of the relief valve, the rodless chamber is in a high-pressure state, the relief valve opens, and the rodless chamber starts to unload oil, which can quickly release the instantaneous high pressure generated by the impact and protect the pipeline and seals.

[0020] 2. The anti-load impact electro-hydraulic actuator provided by the present invention also includes a pressure sensor connected to the first oil circuit for real-time monitoring of the pressure in the rodless chamber; the hydraulic power pump and the three-position four-way solenoid valve are respectively connected to the pressure sensor for communication. When the pressure in the rodless chamber is less than the preset pressure value, the pressure sensor controls the hydraulic power pump to start and controls the three-position four-way solenoid valve to enter the second position.

[0021] The hydraulic power pump and the three-position four-way solenoid directional valve are connected to the pressure sensor. When the external pressure exceeds the set pressure value of the relief valve, the relief valve opens, causing hydraulic oil in the rodless chamber to overflow. This may result in a decrease in the hydraulic oil level in the rodless chamber. The pressure sensor monitors the pressure inside the rodless chamber in real time. When the pressure decreases, the hydraulic power pump and the three-position four-way solenoid directional valve are activated to replenish oil to the rodless chamber, maintaining a stable system operating pressure. This effectively ensures the stability of the electro-hydraulic actuator during pressure holding and resistance to external load impacts. Attached Figure Description

[0022] The specific details of this disclosure are described below with reference to the accompanying drawings, which will facilitate a more readily understanding of the above and other objects, features, and advantages of this disclosure. The drawings are merely for illustrating the principles of this disclosure. The dimensions and relative positions of the elements are not necessarily drawn to scale in the drawings.

[0023] Figure 1 A schematic diagram of the structure of an electro-hydraulic actuator provided in the prior art is shown.

[0024] Figure 2 A schematic diagram of the anti-load impact electro-hydraulic actuator provided by the present invention is shown; Figure 3 A left sectional view of the hydraulic anti-load impact electro-hydraulic actuator provided by the present invention is shown; Figure 4 A right view of the hydraulic anti-load impact electro-hydraulic actuator provided by the present invention is shown; Figure 5 A front view of the hydraulic anti-load impact electro-hydraulic actuator provided by the present invention is shown.

[0025] Background Art, Illustrations and Labeling 1' Rod chamber; 2' Rodless chamber; 3' Check valve; 4' Two-position three-way hydraulic directional valve; 5' Sequence valve.

[0026] Explanation of reference numerals in the attached figures 1. Hydraulic valve block; 2. Oil tank; 3. Servo motor; 4. Piston rod; 5. Rod chamber; 6. Rodless chamber; 7. First oil circuit; 8. Second oil circuit; 9. Three-position four-way solenoid directional valve; 10. Third oil circuit; 11. First valve body; 12. Relief valve; 13. Fourth oil circuit; 14. Second valve body; 15. Pressure sensor; 16. Gear pump; 17. Outer cylinder intermediate connecting seat; 18. First hydraulic check valve; 19. Second hydraulic check valve; 20. Suction pipe; 21. Filter; 22. Balance valve; 23. Coupling; 25. Displacement sensor; 27. Flange assembly; 28. Guide sleeve; 29. ​​Outer cylinder; 30. Inner cylinder. Detailed Implementation

[0027] Exemplary disclosures of this disclosure will be described below with reference to the accompanying drawings. For clarity and brevity, not all features implementing this disclosure are described in the specification. However, it should be understood that many disclosure-specific decisions can be made in developing any such implementation of this disclosure to achieve the developer’s specific goals, and these decisions may vary depending on the specific disclosure.

[0028] It should also be noted that, in order to avoid obscuring this disclosure with unnecessary details, only the device structure closely related to the scheme according to this disclosure is shown in the accompanying drawings, while other details that are not closely related to this disclosure are omitted.

[0029] Generally, it should be understood that the drawings and the various elements depicted therein are not drawn to scale. Furthermore, the use of relative terms (such as "above", "below", "top", "bottom", "upper", and "lower") to describe the relationships between the various elements should be understood to cover different orientations of the device and / or element in addition to the orientations depicted in the drawings.

[0030] It should be understood that this disclosure is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. Throughout this document, features may be substituted or borrowed between different embodiments where feasible, and one or more features may be omitted in one embodiment, wherein the same reference numerals denote the same parts. It should be understood that the manufacturing steps of this disclosure are exemplary in the embodiments, and the order of the steps may be adjusted.

[0031] Example 1 This embodiment provides an anti-load impact electro-hydraulic actuator capable of outputting large thrust and performing stable linear motion. For example... Figures 2-5 As shown, it includes: The hydraulic valve block 1 includes an oil tank 2 and a hydraulic power pump connected to the oil tank 2; like Figure 3 From the perspective shown, the hydraulic valve block 1 is positioned... Figure 3On the right side, the oil tank 2 is located below the hydraulic power pump. The oil tank 2 contains hydraulic oil, which pushes the piston rod 4.

[0032] A hydraulic cylinder is disposed on one side of the hydraulic valve block 1, including a cylinder body and a piston rod 4 disposed in the cylinder body, wherein the piston rod 4 divides the cylinder body into a rod chamber 5 and a rodless chamber 6; like Figure 3 As shown, the hydraulic cylinder is located on the left side of the hydraulic valve block 1. Hydraulic oil flowing through the hydraulic valve block 1 enters the hydraulic cylinder. The hydraulic cylinder includes a cylinder body and a piston rod 4 located inside the cylinder body. The area where the piston rod 4 is located is called the rod chamber 5. Figure 3 As shown, the rodless chamber 6 is located above the rod chamber 5. The piston rod 4 is connected to an external load to drive the external load to move in a linear direction, as shown. Figure 3 From the perspective shown, when oil enters the rod chamber 5, the piston rod 4 moves upward; when oil enters the rodless chamber 6, the piston rod 4 moves downward.

[0033] like Figure 3 As shown, the cylinder block includes an inner cylinder barrel 30 disposed in the inner layer and an outer cylinder barrel 29 disposed in the outer layer. Figure 3 From the perspective shown, a guide sleeve 28 is provided at the lower end of the cylinder block, which keeps the axis of the piston rod 4 aligned with the axis of the cylinder block. Meanwhile, a flange assembly 27 is provided at the end of the cylinder block, which stabilizes the guide sleeve 28 inside the cylinder block.

[0034] The main hydraulic circuit is connected to the oil tank 2 and includes a first oil passage 7 connecting the rodless chamber 6 and a second oil passage 8 connecting the rod chamber 5. A three-position four-way solenoid directional valve 9 is provided on the main hydraulic circuit and has a first position for allowing oil to enter the rod chamber 5, a second position for allowing oil to enter the rodless chamber 6, and a third position for stopping oil from entering the rod chamber 5. The three-position four-way solenoid directional valve 9 adopts a common structure in existing technology. It is a valve that controls the direction of fluid flow through electromagnets. The "three-position" in its name refers to its three working positions, and "four-way" refers to its four ports. Two electromagnets are installed on the three-position four-way solenoid directional valve 9. When the two electromagnets are arranged in a left-right direction, the left electromagnet is energized, and the valve core of the three-position four-way solenoid directional valve 9 moves to the right, at which time the port is connected according to the left-side circuit. When the right electromagnet is energized, the three-position four-way solenoid directional valve 9 moves to the left, at which time the port is connected according to the right-side circuit.

[0035] Specifically, in this embodiment, as Figure 2 As shown, electromagnetic coil S1 and electromagnetic coil S2 are respectively installed on the three-position four-way solenoid directional valve 9: Hydraulic oil enters the rod chamber 5, at which point the three-position four-way solenoid directional valve 9 is in the first position. By energizing and de-energizing the solenoid coils S1 and S2, the piston rod 4 can be extended or retracted, thereby driving the load.

[0036] In this embodiment, when the three-position four-way solenoid directional valve 9 is in the third position, the electro-hydraulic actuator will enter the pressure-holding state: at this time, the first valve body 11 is turned on, and the relief valve 12 will give the rodless chamber 6 a continuous pressure. Only when the pressure of the rodless chamber 6 is greater than the preset pressure of the relief valve 12 will the relief valve 12 open. When the pressure of the external load on the piston rod 4 is less than the preset pressure of the relief valve 12, the relief valve 12 will give the piston rod 4 and the rodless chamber 6 a continuous and stable pressure, so that the hydraulic cylinder maintains a constant clamping force, thereby ensuring that the piston rod 4 can provide a stable thrust to the external load.

[0037] The third oil passage 10 is connected at one end to the first oil passage 7 and at the other end to the oil tank 2. The third oil passage 10 is provided with a first valve body 11 and an overflow valve 12. When the three-position four-way solenoid valve 9 is in the third position, the first valve body 11 is open and the overflow valve 12 is used to open when the pressure of the rodless chamber 6 exceeds the preset pressure value. Specifically, the first oil circuit 7 is connected to the rodless chamber 6. When the three-position four-way solenoid directional valve 9 is in the third position, the electro-hydraulic actuator will enter the pressure holding state. At this time, the first valve body 11 opens, and the relief valve 12 is located downstream of the first valve body 11. The relief valve 12 has a certain preset pressure value. Only when the external pressure is greater than the preset pressure value will the relief valve 12 open, and then the hydraulic oil in the third oil circuit will be discharged into the oil tank 2.

[0038] The fourth oil passage 13 is connected to the second oil passage 8 at one end and to the oil tank 2 at the other end; the fourth oil passage 13 is provided with a second valve body 14, which opens when the overflow valve 12 is opened.

[0039] Specifically, the second oil circuit 8 is connected to the rod chamber 5. The relief valve 12 can only open when the external pressure exceeds the preset pressure value. Therefore, when the external impact is less than the set pressure value, the relief valve 12 will not conduct. When the reverse load is large, exceeding the set pressure value of the relief valve 12, the rodless chamber 6 is in a high-pressure state, the relief valve 12 opens, and the rodless chamber 6 starts unloading oil. Simultaneously, the negative pressure formed in the rodless chamber 6 is further transmitted to the rod chamber 5, creating a negative pressure that is transmitted to the fourth oil circuit 13. This negative pressure then drives the second valve body 14 to open, allowing the hydraulic oil in the oil tank 2 to enter the rod chamber 5 through the fourth oil circuit 13, replenishing the rod chamber 5 with oil.

[0040] In this embodiment, the preset pressure value of the relief valve 12 is 4MPa. The relief valve 12 will only open when the pressure value of the hydraulic oil is greater than 4MPa.

[0041] Through the cooperation of the third oil circuit 10, the fourth oil circuit 13, the first valve body 11, the overflow valve 12, and the second valve body 14, the instantaneous high pressure generated by the impact can be released quickly, protecting the pipeline and seals and other related structures, and ensuring that the electro-hydraulic actuator can maintain structural stability even when subjected to extremely rapid load changes.

[0042] In this embodiment, the configuration of the first valve body 11 and the second valve body 14 is not limited, as long as the on / off effect can be achieved. As one implementation, the second valve body 14 is a pipe-type check valve, and the first valve body 11 is a two-position two-way solenoid valve.

[0043] Specifically, the pipe-type check valve is unidirectional, allowing oil tank 2 to replenish oil to the rod chamber 5 of the cylinder, and is cut off in the reverse direction to maintain the rod chamber 5 full of oil.

[0044] Furthermore, this embodiment also includes: a pressure sensor 15, connected to the first oil circuit 7, for real-time monitoring of the pressure in the rodless chamber 6; the hydraulic power pump and the three-position four-way solenoid valve 9 are respectively connected to the pressure sensor 15. When the pressure in the rodless chamber 6 is less than a preset pressure value, the pressure sensor 15 controls the hydraulic power pump to start and controls the three-position four-way solenoid valve 9 to enter the second position.

[0045] Specifically, pressure sensor 15 collects the pressure of rodless chamber 6 in real time as a signal source for pressure replenishment. It is connected to pressure sensor 15 via a hydraulic power pump and a three-position four-way solenoid valve 9. When the external pressure exceeds the set pressure value of relief valve 12, the hydraulic oil in rodless chamber 6 overflows as relief valve 12 opens. This may cause a decrease in the hydraulic oil level in rodless chamber 6. Pressure sensor 15 monitors the internal pressure of rodless chamber 6 in real time. When the pressure drops, such as below 4 MPa, it controls the hydraulic power pump and three-position four-way solenoid valve 9 to start. The solenoid coil in three-position four-way solenoid valve 9 replenishes oil to rodless chamber 6, maintaining stable system operating pressure. When pressure sensor 15 detects that the pressure in rodless chamber 6 reaches 4 MPa, it sends a signal to the hydraulic power pump to stop working. Simultaneously, the solenoid coil of three-position four-way solenoid valve 9 and the electro-hydraulic actuator re-enter the pressure-holding state. Through the above operations, the stability of the electro-hydraulic actuator during continuous operation and under external load impact is effectively ensured.

[0046] In this embodiment, the configuration of the hydraulic power pump itself is not limited, as long as it can introduce hydraulic oil from the oil tank 2 into the main hydraulic circuit after startup. As one implementation, the hydraulic power pump includes a servo motor 3 and a gear pump 16 connected to the servo motor 3, and a pressure sensor 15 is communicatively connected to the servo motor 3.

[0047] The motor adopts a servo motor 3, which provides stepless control of the output hydraulic oil flow at high and low speeds, thereby effectively adjusting the extension and retraction speed of the hydraulic cylinder.

[0048] Specifically, a filter 21 and an oil suction pipe 20 are provided in the oil tank 2. The oil suction pipe 20 is connected to a gear pump 16. A coupling 23 is provided between the gear pump 16 and the servo motor 3. The gear pump 16 is driven by the coupling 23 to draw the hydraulic oil in the oil tank 2 out of the oil tank 2.

[0049] In this embodiment, as Figure 3 As shown, an outer cylinder intermediate connecting seat 17 is provided between the hydraulic valve block 1 and the hydraulic cylinder, and the outer cylinder intermediate connecting seat 17 is provided with the second oil passage 8.

[0050] Specifically, the middle connecting seat 17 of the outer cylinder itself acts as a connection, serving as a bridge for hydraulic oil exchange between the hydraulic valve block 1 and the hydraulic cylinder, making the overall structure of the electro-hydraulic actuator "H" shaped.

[0051] In this embodiment, in order to ensure the unidirectional flow of hydraulic oil in the first oil circuit 7 and the second oil circuit 8, a first hydraulically controlled check valve 18 is provided on the first oil circuit 7 to control the unidirectional flow of hydraulic oil to the rodless chamber 6, and a second hydraulically controlled check valve 19 is provided on the second oil circuit 8 to control the unidirectional flow of hydraulic oil to the rod chamber 5.

[0052] Specifically, such as Figure 3 and Figure 4 As shown, the first hydraulic check valve 18 is mounted on the intermediate connecting seat 17 of the outer cylinder, and the second hydraulic check valve 19 is mounted on the hydraulic valve block 1. In the pressure-holding state, the first hydraulic check valve 18 and the second hydraulic check valve 19 can close both sides of the cylinder, cutting off the backflow of hydraulic oil and achieving zero-leakage pressure-holding operation.

[0053] Furthermore, this embodiment also includes a displacement sensor 25, such as... Figure 1 As shown, the displacement sensor 25 is located at the top of the hydraulic cylinder to monitor the position of the piston rod 4 in real time. When the piston rod 4 moves to the preset position, the displacement sensor 25 sends a signal to the hydraulic power pump, which stops working. At the same time, the displacement sensor 25 sends a signal to the three-position four-way solenoid valve, which moves it to the neutral position and begins to maintain pressure.

[0054] This embodiment can achieve the following operations: Start-up: Upon receiving a start signal, servo motor 3 starts, driving gear pump 16 to start, and hydraulic oil in oil tank 2 enters suction pipe 20 through filter 21; Piston rod 4 extends: The solenoid coil S1 of the three-position four-way solenoid directional valve 9 is energized, and hydraulic oil enters the first oil circuit 7. At this time, the circuit opens, and hydraulic oil enters the rodless chamber 6, pushing the piston rod 4 to extend and perform work. The hydraulic oil in the rod chamber 5 flows back to the oil tank 2 through the second hydraulic control check valve 19 and the balance valve 22 into the three-position four-way solenoid directional valve 9.

[0055] In this embodiment, the balance valve 22 itself has a one-way overflow valve with a built-in overflow buffer structure, which can absorb hydraulic shock, eliminate vibration and abnormal noise, and ensure the sealing of the hydraulic push rod.

[0056] When the displacement sensor 25 receives the displacement stop signal, the solenoid coil S1 of the three-position four-way solenoid valve 9 is de-energized, and the rod chamber 5 and the rodless chamber 6 are in a pressure-holding state.

[0057] Piston rod 4 retraction: The solenoid coil S2 of the three-position four-way solenoid directional valve 9 is energized, the working circuit is connected, and hydraulic oil enters the second oil circuit 8. The hydraulic oil enters the rod chamber 5 through the balance valve 22 and the second hydraulically controlled check valve 19, pushing the piston rod 4 to retract and perform the work. The hydraulic oil in the rodless chamber 6 flows back to the oil tank 2 through the first hydraulically controlled check valve 18 and the three-position four-way solenoid directional valve 9.

[0058] System pressure holding status: When the displacement sensor 25 receives the displacement stop signal, the solenoid coil S1 of the three-position four-way solenoid directional valve 9 is de-energized. At this time, the first hydraulic check valve 18 and the second hydraulic check valve 19 automatically lock themselves by relying on their own elastic force and the oil pressure in the rod chamber 5 and the rodless chamber 6. The oil passages of the rod chamber 5 and the rodless chamber 6 are completely closed, the piston rod 4 remains in position, and the rod chamber 5 and the rodless chamber 6 are in a pressure-holding state.

[0059] When the first valve body 11 is de-energized, the unloading circuit containing the relief valve 12 is cut off; the inlet pressure of the tubular check valve is lower than the outlet pressure and it is locked, with no oil flow. At this time, the system is in a pressure-maintaining state and has no resistance to external impacts.

[0060] Secondary pressure holding state: When the displacement sensor 25 receives the displacement stop signal, the solenoid coil S1 of the three-position four-way solenoid directional valve 9 is de-energized. At this time, the first hydraulic check valve 18 and the second hydraulic check valve 19 automatically lock themselves by relying on their own elastic force and the oil pressure in the rod chamber 5 and the rodless chamber 6. The oil passages of the rod chamber 5 and the rodless chamber 6 are completely closed, the piston rod 4 remains in position, and the rod chamber 5 and the rodless chamber 6 are in a pressure-holding state.

[0061] When the first valve body 11 is energized, the pressure relief and oil discharge circuit containing the overflow valve 12 is in the connected state; the inlet pressure of the tubular check valve is lower than the outlet pressure and it is locked, with no oil flow. This is the secondary pressure holding state, which can resist external impacts. External impact resistance state: When the load on the piston rod 4 changes drastically, such as a violent reverse load impact from the outside, the external force will push the piston rod 4 to move in the retracting direction. The piston rod 4 squeezes the hydraulic oil in the rodless chamber 6 through the first valve body 11 into the pressure relief and oil discharge circuit of the relief valve 12. The pressure oil in the rodless chamber 6 is maintained within the set pressure value of the secondary relief valve 12, and the excess oil flows into the oil tank 2, completing the active oil discharge of the rodless chamber 6, quickly releasing the instantaneous displacement caused by the external load impact, and protecting the relevant structures of the equipment.

[0062] Simultaneously, during the impact displacement, the piston rod 4 reduces the volume of the rodless chamber 6 and increases the volume of the rod chamber 5, creating a negative pressure in the rod chamber 5. At this time, the pressure on the side of the oil tank 2 will be greater than the oil pressure in the rod chamber 5. Under atmospheric pressure, the hydraulic oil in the oil tank 2 opens the tubular check valve, allowing hydraulic oil to flow unidirectionally into the rod chamber 5, completing active oil replenishment. Furthermore, because the tubular check valve can achieve reverse shut-off, it prevents the hydraulic oil in the rod chamber 5 from flowing back into the oil tank 2, ensuring that the rod chamber 5 is always full of hydraulic oil. This avoids pressure imbalance between the rod chamber 5 and the rodless chamber 6, ensuring stable operation of the electro-hydraulic actuator.

[0063] Through the integrated solution of pressure sensor 15, two-position two-way solenoid valve, and tubular check valve, when the external load changes drastically, the linkage operation of depressurizing rodless chamber 6 and replenishing oil in rod chamber 5 can be realized, effectively offsetting the pressure fluctuations caused by load impact and ensuring the stability of electro-hydraulic actuator.

[0064] Rodless chamber 6 pressure compensation: When the external impact load on piston rod 4 decays, the pressure in rodless chamber 6 decreases. When the pressure falls below the set value, pressure sensor 15 detects a signal and energizes coil S1 of three-position four-way solenoid directional valve 9. At this time, the main hydraulic circuit is activated, servo motor 3 and gear pump 16 start, and hydraulic oil in tank 2 passes through first hydraulic check valve 18 and then enters rodless chamber 6 to replenish oil pressure. When the pressure in rodless chamber 6 rises back to the preset pressure value, such as 4 MPa, pressure sensor 15 sends a signal again, coil S1 is de-energized, and the main hydraulic circuit is closed.

[0065] Example 2 This embodiment also provides a mechanical device, including the electro-hydraulic actuator provided in Embodiment 1.

[0066] Specifically, the mechanical equipment can be lifting equipment, such as gantry cranes; conveying equipment, such as belt conveyors; hydraulic equipment, used on floodgates; or metallurgical or mining equipment, such as steel rolling production lines or coal mine hydraulic supports, etc.

[0067] The present disclosure has been described above with reference to specific implementation schemes. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present disclosure. Those skilled in the art can make various modifications and variations to the present disclosure based on its spirit and principles, and such modifications and variations are also within the scope of the present disclosure.

Claims

1. An anti-load impact electro-hydraulic actuator, characterized in that, include: The hydraulic valve block (1) includes an oil tank (2) and a hydraulic power pump connected to the oil tank (2); The hydraulic cylinder is located on one side of the hydraulic valve block (1) and includes a cylinder body and a piston rod (4) located in the cylinder body. The piston rod (4) divides the cylinder body into a rod chamber (5) and a rodless chamber (6). The main hydraulic circuit is connected to the oil tank (2) and includes a first oil circuit (7) connecting the rodless chamber (6) and a second oil circuit (8) connecting the rod chamber (5). A three-position four-way solenoid directional valve (9) is provided on the main hydraulic circuit and has a first position for allowing oil to enter the rod chamber (5), a second position for allowing oil to enter the rodless chamber (6), and a third position for stopping oil from entering the rod chamber (5). The third oil passage (10) is connected at one end to the first oil passage (7) and at the other end to the oil tank (2); the third oil passage (10) is provided with a first valve body (11) and an overflow valve (12). When the three-position four-way solenoid valve (9) is in the third position, the first valve body (11) is turned on, and the overflow valve (12) is used to open when the pressure in the rodless chamber (6) exceeds the preset pressure value. The fourth oil passage (13) is connected at one end to the second oil passage (8) and at the other end to the oil tank (2); the fourth oil passage (13) is provided with a second valve body (14), which opens when the overflow valve (12) is opened.

2. The anti-load impact electro-hydraulic actuator according to claim 1, characterized in that, Also includes: A pressure sensor (15) is connected to the first oil circuit (7) to monitor the pressure of the rodless chamber (6) in real time. The hydraulic power pump and the three-position four-way solenoid valve (9) are respectively connected to the pressure sensor (15). When the pressure in the rodless chamber (6) is less than the preset pressure value, the pressure sensor (15) controls the hydraulic power pump to start and controls the three-position four-way solenoid valve (9) to enter the second position.

3. The anti-load impact electro-hydraulic actuator according to claim 2, characterized in that, The hydraulic power pump includes a servo motor (3) and a gear pump (16) connected to the servo motor (3). The pressure sensor (15) is communicatively connected to the servo motor (3).

4. The anti-load impact electro-hydraulic actuator according to claim 1, characterized in that, An outer cylinder intermediate connecting seat (17) is provided between the hydraulic valve block (1) and the hydraulic cylinder, and the outer cylinder intermediate connecting seat (17) is provided with the second oil passage (8).

5. The anti-load impact electro-hydraulic actuator according to claim 4, characterized in that, The first hydraulic circuit (7) is provided with a first hydraulic control check valve (18), which is used to control the hydraulic oil to flow unidirectionally to the rodless chamber (6). The second hydraulic circuit (8) is provided with a second hydraulic control check valve (19), which is used to control the hydraulic oil to flow unidirectionally to the rod chamber (5).

6. The anti-load impact electro-hydraulic actuator according to claim 5, characterized in that, The first hydraulic control check valve (18) is mounted on the middle connecting seat (17) of the outer cylinder, and the second hydraulic control check valve (19) is mounted on the hydraulic valve block (1).

7. The anti-load impact electro-hydraulic actuator according to claim 1, characterized in that, The second valve body (14) is a pipe-type check valve, and the first valve body (11) is a two-position two-way solenoid valve.

8. The anti-load impact electro-hydraulic actuator according to claim 1, characterized in that, It also includes a displacement sensor, which is located at the top of the hydraulic cylinder to monitor the position of the piston rod in real time.

9. The anti-load impact electro-hydraulic actuator according to claim 1, characterized in that, The displacement sensor is communicatively connected to the hydraulic power pump and the three-position four-way solenoid directional valve, respectively.

10. A mechanical device, characterized in that, Includes the electro-hydraulic actuator as described in any one of claims 1 to 9.

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