A proportional directional control valve for a heave compensation system and a working method thereof

Abstract

The present invention relates to a proportional directional control valve for a wave compensation system and a working method thereof, and belongs to the technical field of marine heave compensation engineering equipment. The control valve includes a controller, a three-position four-way proportional reversing valve and a two-position three-way proportional reversing valve. The three-position four-way proportional reversing valve includes an electromagnet A, an electromagnet B, a main valve core and a main valve body. The main valve core is arranged in the main valve body. One end of the main valve body is connected to the electromagnet A through an intermediate valve body, and the other end is connected to the electromagnet B. One end of the electromagnet A and the electromagnet B are respectively provided with a return spring A and a return spring B. The electromagnet A and the electromagnet B are respectively provided with a push rod A and a push rod B. The push rod B contacts the main valve core. The push rod A is connected to a connecting valve core through a transition valve core, and the connecting valve core contacts the main valve core. The present invention solves the problem of electrical system failure of the control valve that may exist in the traditional proportional directional control valve under special working conditions, thereby achieving high reliability and high stability of the system.

Description

Technical Field

[0001] The invention relates to a proportional directional control valve for a wave compensation system and a working method thereof, belonging to the technical field of marine heave compensation engineering equipment. Background Art

[0002] In the application of marine heave compensation equipment, the proportional directional control valve is the core component for adjusting the oil flow direction and pressure in the hydraulic system. It is widely used in deep-sea drilling platforms, offshore oil production equipment, submersibles and other fields, especially the heave compensation system of deep-sea drilling platforms and the attitude adjustment system of offshore floating platforms. These equipment are usually faced with extreme environmental conditions, such as high water pressure, large temperature difference, and complex ocean currents and waves. The stability and reliability of the operating system are crucial to ensuring the safety of equipment and personnel lives.

[0003] At present, the commonly used dual-proportional solenoid-driven proportional directional control valve is widely used in the compensation system of these equipment. However, the existing technology has certain limitations in the case of electrical failure. When the electrical signal fails, the traditional proportional valve usually stays in the neutral state, causing the hydraulic system to fail to work normally. This failure mode may cause serious consequences in critical tasks, such as:

[0004] 1) Loss of control of the compensation system: The proportional valve stays in the middle position, which may cause the heave compensation system of the deep-sea drilling platform or the attitude adjustment system of the offshore floating platform to fail to adjust the position normally, affecting the stability or depth adjustment of the platform, and further affecting the safety and accuracy of the operation.

[0005] 2) Safety hazards: In the event of an electrical failure, the valve core cannot return to the predetermined safe position in time, which will cause the hydraulic system to be unable to effectively regulate pressure, increase the risk of system overload or failure, and may endanger the structural safety of the equipment or the life safety of the operator.

[0006] 3) Increased difficulty in operation and maintenance: Failure of proportional valves caused by electrical faults often requires manual intervention for repair or replacement, which not only affects the progress of operations, but also increases the complexity and cost of equipment maintenance.

[0007] At present, although some high-end control systems, such as Chinese patent document CN117416892A, use redundant proportional solenoid valves or mechanical locking devices to reduce these risks, these measures often increase the complexity, cost and maintenance difficulty of the system, and it is still difficult to completely eliminate the uncertainty caused by electrical failures.

[0008] Therefore, a new technical solution is urgently needed that can ensure that the proportional directional valve is in a safe working state through the structural automation mechanism when an electrical failure occurs, so as to avoid system loss of control or safety hazards caused by the failure. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention provides a proportional directional control valve for a wave compensation system, which solves the problem of control valve electrical system failure that may exist in traditional proportional directional control valves under special working conditions, especially in complex environments such as marine heave compensation equipment, thereby achieving high reliability and high stability of the system.

[0010] The present invention also provides a working method of the proportional directional control valve used in the heave compensation system.

[0011] The technical solution of the present invention is as follows:

[0012] A proportional directional control valve for a wave compensation system with a safety function comprises a controller, a three-position four-way proportional reversing valve and a two-position three-way proportional reversing valve, one side of the three-position four-way proportional reversing valve is connected to the two-position three-way proportional reversing valve, and both the three-position four-way proportional reversing valve and the two-position three-way proportional reversing valve are connected to the controller;

[0013] The three-position four-way proportional reversing valve comprises an electromagnet A, an electromagnet B, a main valve core, a main valve body, a push rod A, a transition valve core and a connecting valve core. The main valve core is arranged in the main valve body. One end of the main valve body is connected with the electromagnet A through an intermediate valve body, and the other end is sealed and connected with the electromagnet B through an O-ring A. The ends of the electromagnet A and the electromagnet B close to the main valve body are respectively provided with a return spring A and a return spring B through a spring seat. Push rods A and push rods B are respectively arranged in the electromagnet A and the electromagnet B. After the push rod B passes through the return spring B, it contacts the main valve core. The push rod A is connected to the connecting valve core through the transition valve core, and the connecting valve core contacts the main valve core after passing through the return spring A.

[0014] Preferably, according to the present invention, a four-way A port and a four-way B port are arranged in parallel on one side of the main valve body, a four-way P port is arranged between the four-way A port and the four-way B port, a four-way T port is arranged on the other side of the main valve body, and an oil channel is arranged on the main valve core. Different interface connections are realized by utilizing the left and right movement of the main valve core. This is a commonly used design of the valve core.

[0015] Preferably, according to the present invention, the transition valve core is in the shape of a stepped shaft and is composed of three sections of cylinders with different diameters. The diameters of the three sections of cylinders increase successively. The section of cylinder with the largest diameter of the transition valve core is sealed by an O-ring B and is arranged in the inner cavity of the electromagnet A. The middle cylinder forms a gap with the inner cavity of the electromagnet A as the accommodating cavity A. The section of cylinder with the smallest diameter of the transition valve core is inserted into the connecting valve core to ensure its stability and coaxiality during movement.

[0016] Preferably according to the present invention, the connecting valve core is a convex column with a hollow interior. The connecting valve core is sealed in the inner cavity of the electromagnet A through an O-ring C. A transition valve core is provided at one end of the connecting valve core, and the other end of the connecting valve core contacts the main valve core and is fitted with a reset spring A.

[0017] Preferably, according to the present invention, the gap between the push rod A and the electromagnet A is the push rod cavity, the space where the reset spring A is located is the cavity B, the electromagnet A is provided with a flow channel a connecting the push rod cavity and the cavity B, the cavity B is connected with a four-way T-port, and the cavity A is connected with a two-position three-way proportional reversing valve through the flow channel b to complete the lead-out and return of high-pressure oil and low-pressure oil, and the flow channel b passes through the electromagnet A, the intermediate valve body and the main valve body in sequence.

[0018] Preferably, according to the present invention, a limit plate is provided in the inner cavity of the electromagnet A, and the limit plate is located between the connection port position of the flow channel a in the push rod cavity and the transition valve core.

[0019] Preferably according to the present invention, a two-position three-way proportional directional valve comprises an electromagnet C, a push rod C, an auxiliary valve body and an auxiliary valve core, wherein an auxiliary valve core is arranged in the auxiliary valve body, an electromagnet C is arranged at one end of the auxiliary valve body, a push rod C is arranged in the electromagnet C, and a return spring C is mounted on one end of the push rod C close to the auxiliary valve core.

[0020] Preferably according to the present invention, a three-way P port, a three-way A port and a three-way T port are arranged in parallel on one side of the auxiliary valve body, and the three-way A port is connected to the flow channel b.

[0021] The working method of the proportional directional control valve for the heave compensation system with safety function is as follows:

[0022] (1) Under normal working conditions, when the controller controls the solenoid A, the push rod A pushes the transition valve core and the connecting valve core, and the force is transmitted to the main valve core, realizing the right position switching of the three-position four-way proportional reversing valve, and the high-pressure oil at the four-way P port enters the four-way B port;

[0023] When the controller controls the electromagnet B, the push rod B pushes the main valve core to realize the left position switching of the three-position four-way proportional reversing valve. The high-pressure oil of the four-way P port enters the four-way A port. In this process, the main valve core pushes the connecting valve core and the transition valve core to move to the left as a whole, resulting in a decrease in the volume of the left push rod chamber. Therefore, the oil in the push rod chamber is connected to the four-way T port through the flow channel a, so that the pressure in the push rod chamber always maintains a dynamic balance;

[0024] At the same time, the controller sends a ready signal to the electromagnet C, so that the two-position three-way proportional reversing valve remains energized. At this time, the three-way T port of the two-position three-way proportional reversing valve is connected to the three-way A port, and the three-way T port of the two-position three-way proportional reversing valve is connected to the four-way T port of the three-position four-way proportional reversing valve, providing a low-pressure oil return channel, so that when the main valve core of the three-position four-way proportional reversing valve moves to the left or right position, the oil pressure in the chamber A is kept balanced;

[0025] (2) In the event of an electrical failure or power outage, solenoid A, solenoid B and solenoid C are all de-energized. The main valve core returns to the middle position under the action of the return spring A and the return spring B, and the auxiliary valve core returns to the initial position under the action of the return spring C. At this time, the three-way P port is connected to the three-way A port, and the high-pressure oil in the four-way P port is connected to the three-way P port to provide high-pressure oil for the three-way A port. The high-pressure oil flowing out of the three-way A port enters the volume A through the flow channel b. At this time, the high-pressure oil increases the volume of the volume A. Under the action of the limit plate, the transition valve core stroke is controlled so that the high-pressure oil cannot push the transition valve core to the left. Therefore, the oil can only push the connecting valve core to overcome the force of the return spring A and move to the right, thereby pushing the main valve core to move to the right, so that the three-position four-way proportional reversing valve reaches the right position, so that the high-pressure oil in the four-way P port enters the four-way B port. This function can drive the main valve core to enter the safe position and ensure the reliability of the hydraulic system.

[0026] The beneficial effects of the present invention are:

[0027] 1. The present invention optimizes the structure of the three-position four-way proportional reversing valve and the two-position three-way proportional reversing valve: a three-section diameter design of the transition valve core is adopted, and the force and limit function are reasonably distributed to ensure that the connecting valve core can be accurately in place when pushed by high-pressure oil, and at the same time prevent the leakage of high-pressure oil in the push rod chamber. The introduction of the intermediate valve body realizes the separation of the flow channel functions between the main valve body, the transition valve core and the auxiliary two-position three-way proportional reversing valve, reduces the design complexity of the hydraulic system, and realizes the precise distribution of the flow channel of the two-position three-way proportional reversing valve. The setting of the bottom flow channel a effectively solves the problem that the push rod chamber cannot return oil in the traditional design, and further improves the stability and response efficiency of the system operation.

[0028] 2. The present invention combines a two-position three-way proportional directional valve with a three-position four-way electromagnetic proportional valve by adding an intermediate valve body and optimizing the design of the flow channel. There is no need to make major changes to the original main valve body, avoid redesigning the entire hydraulic system, reduce the difficulty of design and manufacturing, and reduce the cost of system modification.

[0029] 3. In marine heave compensation equipment, due to the complex deep-sea environment and harsh operating conditions, the hydraulic system may be affected by sudden conditions such as electrical failures. The present invention designs a specific safety position function. In the event of an electrical failure, the valve core can be locked to a specific working position through auxiliary hydraulic control, ensuring that the core functions of the heave compensation equipment continue to operate stably, greatly improving the reliability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the main structure of the present invention;

[0031] Figure 2 It is a schematic diagram of the top view structure of the present invention;

[0032] Figure 3 It is a schematic diagram of a two-dimensional cross-sectional structure of the present invention;

[0033] Figure 4 It is a schematic diagram of assembling the transition valve core of the present invention;

[0034] Figure 5 It is a three-dimensional schematic diagram of the transition valve core of the present invention;

[0035] Figure 6 A three-dimensional schematic diagram of the connecting valve core of the present invention;

[0036] Figure 7 It is a three-dimensional schematic diagram of the intermediate valve body of the present invention;

[0037] Figure 8 It is a two-dimensional cross-sectional structural schematic diagram of a two-position three-way proportional reversing valve of the present invention;

[0038] In the figure, 1-three-position four-way proportional reversing valve; 2-two-position three-way proportional reversing valve;

[0039] 11-electromagnet A; 12-push rod A; 13-transition valve core; 14-communication valve core; 15-main valve core; 16-main valve body; 17-O-ring A; 18-electromagnet B; 19-reset spring A; 110-spring seat; 111-intermediate valve body; 112-O-ring C; 113-O-ring B; 114-push rod B; 115-reset spring B; 116-four-way P port; 117-four-way A port; 118-four-way B port; 119-four-way T port; 120-cavity A; 121-cavity B; 122-push rod cavity; 123-flow channel a; 124-flow channel b; 125-limiting plate;

[0040] 21-electromagnet C; 22-push rod C; 23-three-way P port; 24-auxiliary valve body; 25-auxiliary valve core; 26-reset spring C; 27-three-way A port; 28-three-way T port. DETAILED DESCRIPTION

[0041] The present invention will be further described below by way of embodiments in conjunction with the accompanying drawings, but is not limited thereto.

[0042] Embodiment 1:

[0043] like Figure 1-Figure 8 As shown, this embodiment provides a proportional directional control valve for a heave compensation system with a safety function, comprising a controller, a three-position four-way proportional directional control valve 1 and a two-position three-way proportional directional control valve 2, wherein one side of the three-position four-way proportional directional control valve 1 is connected to the two-position three-way proportional directional control valve 2, and both the three-position four-way proportional directional control valve 1 and the two-position three-way proportional directional control valve 2 are connected to the controller;

[0044] The three-position four-way proportional reversing valve 1 comprises an electromagnet A11, an electromagnet B18, a main valve core 15, a main valve body 16, a push rod A12, a transition valve core 13 and a connecting valve core 14. The main valve core 15 is arranged in the main valve body 16. One end of the main valve body 16 is connected to the electromagnet A11 through an intermediate valve body 111, and the other end is sealed and connected to the electromagnet B18 through an O-ring A17. The ends of the electromagnet A11 and the electromagnet B18 close to the main valve body 16 are respectively provided with a return spring A19 and a return spring B115 through a spring seat 110. Push rods A12 and B114 are respectively arranged in the electromagnet A11 and the electromagnet B18. The push rod B114 contacts the main valve core 15 after passing through the return spring B115. The push rod A12 is connected to the connecting valve core 14 through the transition valve core 13. The connecting valve core 14 contacts the main valve core 15 after passing through the return spring A19.

[0045] A four-way A port 117 and a four-way B port 118 are arranged in parallel on one side of the main valve body 16, a four-way P port 116 is arranged between the four-way A port 117 and the four-way B port 118, and a four-way T port 119 is arranged on the other side of the main valve body 16. An oil channel is arranged on the main valve core, and different interfaces are connected by utilizing the left and right movement of the main valve core. This is a commonly used design of the valve core.

[0046] The transition valve core 13 is in the shape of a stepped shaft and is composed of three sections of cylinders with different diameters. The diameters of the three sections of cylinders increase successively. The section of the cylinder with the largest diameter of the transition valve core is sealed in the inner cavity of the electromagnet A11 by an O-ring B113. A gap is formed between the middle cylinder and the inner cavity of the electromagnet A11 as the volume cavity A120. The section of the cylinder with the smallest diameter of the transition valve core 13 is inserted into the connecting valve core 14 to ensure its stability and coaxiality during movement.

[0047] The connecting valve core 14 is a convex column with a hollow interior. The connecting valve core 14 is sealed in the inner cavity of the electromagnet A11 through an O-ring C112. A transition valve core 13 is provided at one end of the connecting valve core 14, and the other end of the connecting valve core 14 contacts the main valve core 15 and is provided with a return spring A19.

[0048] The gap between the push rod A12 and the electromagnet A11 is the push rod chamber 122, and the space where the return spring A19 is located is the chamber B121. The electromagnet A11 is provided with a flow channel a123 connecting the push rod chamber 122 and the chamber B121. The chamber B121 is connected to the four-way T-port 119. The chamber A120 is connected to the two-position three-way proportional reversing valve 2 through the flow channel b124 to complete the lead-out and return of high-pressure oil and low-pressure oil. The flow channel b124 passes through the electromagnet A11, the intermediate valve body 111 and the main valve body 16 in sequence.

[0049] A limit plate 125 is provided in the inner cavity of the electromagnet A11 , and the limit plate 125 is located between the connection port of the flow channel a123 in the push rod cavity and the transition valve core 13 .

[0050] The two-position three-way proportional reversing valve 2 includes an electromagnet C21, a push rod C22, an auxiliary valve body 24 and an auxiliary valve core 25, wherein the auxiliary valve core 25 is arranged in the auxiliary valve body 24, the electromagnet C21 is arranged at one end of the auxiliary valve body 24, the push rod C22 is arranged in the electromagnet C21, and a return spring C26 is sleeved on the end of the push rod C22 close to the auxiliary valve core 25.

[0051] A three-way P port 23 , a three-way A port 27 and a three-way T port 28 are arranged in parallel on one side of the auxiliary valve body 24 , and the three-way A port 27 is connected to the flow channel b124 .

[0052] The working method of the proportional directional control valve for the heave compensation system with safety function is as follows:

[0053] (1) Under normal working conditions, when the controller controls the solenoid A11, the push rod A12 pushes the transition valve core 13 and the connecting valve core 14, and the force is transmitted to the main valve core 15, realizing the right position switching of the three-position four-way proportional reversing valve 1, and the high-pressure oil of the four-way P port 116 enters the four-way B port 118;

[0054] When the controller controls the electromagnet B18, the push rod B114 pushes the main valve core 15 to realize the left position switching of the three-position four-way proportional reversing valve, and the high-pressure oil of the four-way P port 116 enters the four-way A port 117. In this process, the main valve core 15 pushes the connecting valve core 14 and the transition valve core 13 to move leftward as a whole, resulting in a decrease in the volume of the left push rod chamber 122. Therefore, the oil in the push rod chamber 122 is connected to the four-way T port 119 through the flow channel a123, so that the pressure in the push rod chamber 122 always maintains a dynamic balance;

[0055] At the same time, the controller sends a ready signal to the electromagnet C21, so that the two-position three-way proportional reversing valve 2 remains energized. At this time, the three-way T port 28 of the two-position three-way proportional reversing valve 2 is connected to the three-way A port 27, and the three-way T port 28 of the two-position three-way proportional reversing valve 2 is connected to the four-way T port 119 of the three-position four-way proportional reversing valve 1, providing a low-pressure oil return channel, so that when the main valve core 15 of the three-position four-way proportional reversing valve 1 moves to the left position or the right position, the oil pressure in the chamber A120 is kept balanced;

[0056] (2) In the event of an electrical failure or power outage, the solenoid A11, solenoid B18 and solenoid C21 are all de-energized, the main valve core 15 returns to the middle position under the action of the return spring A19 and the return spring B115, and the auxiliary valve core returns to the initial position under the action of the return spring C26. At this time, the three-way P port 23 is connected to the three-way A port 27, and the high-pressure oil in the four-way P port 116 is connected to the three-way P port 23, providing high-pressure oil for the three-way A port 27. The high-pressure oil flowing out of the three-way A port 27 enters the volume chamber A1 through the flow channel b124. 20. At this time, the high-pressure oil increases the volume of the chamber A120. Under the action of the limit plate 125, the stroke of the transition valve core 13 is controlled, so that the high-pressure oil cannot push the transition valve core 13 to the left. Therefore, the oil can only push the connecting valve core 14 to move to the right to overcome the force of the reset spring A19, and then push the main valve core 15 to move to the right, so that the three-position four-way proportional reversing valve 1 reaches the right position, and the high-pressure oil of the four-way P port 116 enters the four-way B port 118. This function can drive the main valve core to enter the safe position and ensure the reliability of the hydraulic system.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A proportional directional control valve for a heave compensation system with a safety function, characterized in that: It includes a controller, a three-position four-way proportional reversing valve and a two-position three-way proportional reversing valve, one side of the three-position four-way proportional reversing valve is connected to the two-position three-way proportional reversing valve, and both the three-position four-way proportional reversing valve and the two-position three-way proportional reversing valve are connected to the controller; The three-position four-way proportional reversing valve comprises an electromagnet A, an electromagnet B, a main valve core, a main valve body, a push rod A, a transition valve core and a connecting valve core. The main valve core is arranged in the main valve body. One end of the main valve body is connected to the electromagnet A through the intermediate valve body, and the other end is connected to the electromagnet B. The ends of the electromagnet A and the electromagnet B close to the main valve body are respectively provided with a return spring A and a return spring B through a spring seat. The electromagnet A and the electromagnet B are respectively provided with a push rod A and a push rod B. The push rod B contacts the main valve core after passing through the return spring B. The push rod A is connected to the connecting valve core through the transition valve core, and the connecting valve core contacts the main valve core after passing through the return spring A. A gap is formed between the middle cylinder of the transition valve core and the inner cavity of the electromagnet A, serving as the chamber A. The chamber A is connected to a two-position three-way proportional directional valve through a flow channel b. The two-position three-way proportional directional valve includes an electromagnet C. In the event of an electrical failure or power outage, electromagnet A, electromagnet B and electromagnet C are all de-energized, the three-way P port is connected to the three-way A port, and the high-pressure oil flowing out of the three-way A port enters the cavity A through the flow channel b. The high-pressure oil increases the volume of the cavity A, and the high-pressure oil cannot push the transition valve core to the left, so the oil can only push the connecting valve core to overcome the force of the reset spring A and move to the right, thereby pushing the main valve core to the right, so that the three-position four-way proportional reversing valve reaches the right position, so that the high-pressure oil at the four-way P port enters the four-way B port, and drives the main valve core to enter the safe position.

2. The proportional directional control valve for a heave compensation system with a safety function according to claim 1, characterized in that: A four-way A port and a four-way B port are arranged in parallel on one side of the main valve body, a four-way P port is arranged between the four-way A port and the four-way B port, and a four-way T port is arranged on the other side of the main valve body.

3. The proportional directional control valve for a heave compensation system with a safety function according to claim 2, characterized in that: The transition valve core is in the shape of a stepped shaft and is composed of three sections of cylinders with different diameters. The diameters of the three sections of cylinders increase successively. The section of the cylinder with the largest diameter of the transition valve core is arranged in the inner cavity of electromagnet A, and the section of the cylinder with the smallest diameter of the transition valve core is inserted into the connecting valve core.

4. The proportional directional control valve for a heave compensation system with a safety function according to claim 3, characterized in that: The connecting valve core is a convex column with a hollow interior. A transition valve core is arranged at one end of the connecting valve core, and the other end of the connecting valve core contacts the main valve core and is provided with a reset spring A.

5. The proportional directional control valve for a heave compensation system with a safety function according to claim 4, characterized in that: The gap between the push rod A and the electromagnet A is the push rod cavity, the space where the return spring A is located is the cavity B, the electromagnet A is provided with a flow channel a connecting the push rod cavity and the cavity B, the cavity B is connected with a four-way T port, and the flow channel b passes through the electromagnet A, the intermediate valve body and the main valve body in sequence.

6. The proportional directional control valve for a heave compensation system with a safety function according to claim 5, characterized in that: A limit plate is arranged in the inner cavity of the electromagnet A, and the limit plate is located between the connection port position of the flow channel a in the push rod cavity and the transition valve core.

7. The proportional directional control valve for a heave compensation system with a safety function according to claim 6, characterized in that: The two-position three-way proportional reversing valve also includes a push rod C, an auxiliary valve body and an auxiliary valve core, wherein the auxiliary valve core is arranged in the auxiliary valve body, an electromagnet C is arranged at one end of the auxiliary valve body, a push rod C is arranged in the electromagnet C, and a return spring C is sleeved on the end of the push rod C close to the auxiliary valve core.

8. The proportional directional control valve for a heave compensation system with a safety function according to claim 7, characterized in that: A three-way P port, a three-way A port and a three-way T port are arranged in parallel on one side of the auxiliary valve body, and the three-way A port is connected to the flow channel b.

9. The operating method of the proportional directional control valve for a heave compensation system with a safety function according to claim 8, characterized in that: Here are the steps: (1) Under normal working conditions, when the controller controls the solenoid A, the push rod A pushes the transition valve core and the connecting valve core, and the force is transmitted to the main valve core, realizing the right position switching of the three-position four-way proportional reversing valve, and the high-pressure oil at the four-way P port enters the four-way B port; When the controller controls the electromagnet B, the push rod B pushes the main valve core to realize the left position switching of the three-position four-way proportional reversing valve. The high-pressure oil of the four-way P port enters the four-way A port. In this process, the main valve core pushes the connecting valve core and the transition valve core to move to the left as a whole, resulting in a decrease in the volume of the left push rod chamber. Therefore, the oil in the push rod chamber is connected to the four-way T port through the flow channel a, so that the pressure in the push rod chamber always maintains a dynamic balance; At the same time, the controller sends a ready signal to the electromagnet C, so that the two-position three-way proportional reversing valve remains energized. At this time, the three-way T port of the two-position three-way proportional reversing valve is connected to the three-way A port, and the three-way T port of the two-position three-way proportional reversing valve is connected to the four-way T port of the three-position four-way proportional reversing valve, providing a low-pressure oil return channel, so that when the main valve core of the three-position four-way proportional reversing valve moves to the left or right position, the oil pressure in the chamber A is kept balanced; (2) In the event of an electrical failure or power outage, electromagnet A, electromagnet B and electromagnet C are all de-energized, and the main valve core returns to the middle position under the action of reset spring A and reset spring B. The auxiliary valve core is reset to the initial position under the action of reset spring C. At this time, the three-way P port is connected to the three-way A port, and the high-pressure oil in the four-way P port is connected to the three-way P port to provide high-pressure oil for the three-way A port. The high-pressure oil flowing out of the three-way A port enters the volume A through the flow channel b. At this time, the high-pressure oil increases the volume of the volume A. Under the action of the limit plate, the transition valve core stroke is controlled so that the high-pressure oil cannot push the transition valve core to the left. Therefore, the oil can only push the connecting valve core to overcome the force of the reset spring A and move to the right, thereby pushing the main valve core to move to the right, so that the three-position four-way proportional reversing valve reaches the right position, so that the high-pressure oil at the four-way P port enters the four-way B port.

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