A control method for an electro-hydraulic control valve

Abstract

The present invention relates to a control method of an electro-hydraulic control valve, wherein the electro-hydraulic control valve comprises a pilot solenoid valve, a gear reversing slide valve assembly, a pressure control valve assembly and a valve body, wherein a P oil port, an E cavity and an F cavity are provided in the valve body, and a T2 oil port, an A1 oil port, a K1 oil port, a P2 oil port, a K1 oil port, a B1 oil port and a T2 oil port are provided in the middle of the gear reversing slide valve assembly in the valve body, a P1 cavity and an H cavity are provided on both sides of the valve body, an A2 oil port, a B cavity and a T2 oil port are provided on the pilot solenoid valve, and a P1 cavity and an H cavity are provided on the pilot solenoid valve. 2 oil port, T1 oil port and P3 oil port. When the pilot solenoid valve YV1 electromagnet is energized, the P3 oil port is connected to the A2 oil port, the reversing valve core moves right, the P2 oil port and the A1 oil port are connected, and the oil enters the first gear clutch. When the pilot solenoid valve YV2 electromagnet is energized, the P3 oil port is connected to the B2 oil port, the reversing valve core moves left, the P2 oil port and the B1 oil port are connected, and the oil enters the second gear clutch. The method of the present invention makes the overall operation of the control valve stable and the response fast.

Description

Technical Field

[0001] The present invention relates to a control method for an electro-hydraulic control valve, which is particularly suitable for medium and large ships and other transmission devices with wet hydraulic friction clutches, and has the functions of controlling clutch engagement and disengagement pressure and realizing gear shifting. Background Art

[0002] Existing electro-hydraulic shift control valves for medium- and large-scale ship transmissions typically consist of two separate components: a pressure control valve and a gear control valve. These valves are connected by external piping. Gear shifting is directly controlled by a solenoid valve. Under high flow conditions, the corresponding solenoid valves are both large and heavy. Separate arrangements for the pressure control valve and gear control valve also present drawbacks such as complex external piping, slow response, and numerous failure points.

[0003] Patent document CN103836019A discloses a fast-fill hydraulic shift valve, which primarily comprises a fast-fill oil circuit and a buffer boost oil circuit. The buffer boost oil circuit includes a valve body, a pressure-regulating valve core, an oil inlet throttle, an accumulator main spring, an accumulator secondary spring, an accumulator plunger, a buffer throttle, a pressure-setting valve core spring, a pressure-setting valve core, and a check valve. The fast-fill oil circuit includes a two-position three-way valve, a check valve, and a check valve. The fast-fill oil circuit allows hydraulic oil to be charged into the shift clutch cylinder at the fastest speed, effectively shortening shifting time.

[0004] Patent document CN206206569U discloses an auxiliary pressure regulating device for a loader shift control valve. This device is installed on an existing shift control valve and consists of a pilot valve and an auxiliary valve. The oil pipe on the top of the pilot valve is connected to the shift clutch oil circuit. When the shift clutch is working, the hydraulic oil acts on the pilot valve at the same time to control the opening and closing of the pilot valve. When the pilot valve is opened, the hydraulic oil from the oil pump flows through the pilot valve to the auxiliary device. The auxiliary device applies a leftward force to the accumulator piston through a push rod, thereby changing the buffering effect of the buffer device and adjusting the pressure regulating characteristics of the buffer device. The shift control valve provided by the utility model can meet the shift quality requirements of more gears of the automatic transmission, thereby improving the driving comfort of the driver and increasing the service life of the sliding wear components.

[0005] The above structures are not suitable for electro-hydraulic shift control valves for medium and large ship transmissions, and cannot overcome the defects of existing electro-hydraulic shift control valves for medium and large ship transmissions, such as large size, complex structure, unstable control, slow response, and easy failure. Summary of the Invention

[0006] In order to solve the above technical problems, an object of the present invention is to provide a control method for an electro-hydraulic control valve, which can realize shift control more quickly and stably.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A control method for an electro-hydraulic control valve, the electro-hydraulic control valve comprising a pilot solenoid valve, a gear reversing slide valve assembly, a pressure control valve assembly, and a valve body, wherein the gear reversing slide valve assembly and the pressure control valve assembly are arranged side by side in the valve body, the pilot solenoid valve is arranged on the upper portion of the gear reversing slide valve assembly, the gear reversing slide valve assembly comprises a reversing valve core connected to the valve body via springs at both ends, the pressure control valve assembly comprises a control piston and a delay piston arranged in the valve body via springs, and the valve body is provided with a P oil port, a P4 oil port, an E cavity, and an F cavity for oil inlet. The E cavity and the F cavity are respectively located at the two ends of the gear reversing slide valve assembly. The valve body is located in the middle of the gear reversing slide valve assembly and is further provided with a T2 oil port, an A1 oil port, a K1 oil port, a P2 oil port, a K1 oil port, a B1 oil port, and a T2 oil port in sequence. The A1 oil port and the B1 oil port are connected to the first gear clutch and the second gear clutch, respectively. A P1 cavity and an H cavity are also provided on both sides of the valve body, and the P1 cavity and the H cavity are respectively located at the two ends of the pressure control valve assembly. The K1 oil port is communicated with the H cavity, and the P oil port is communicated with the P1 cavity through the oil passage J on the pressure control valve assembly. The pilot solenoid valve is provided with an A2 oil port, a B2 oil port, a T1 oil port, and a P3 oil port. The A2 oil port and the B2 oil port are respectively connected to the E cavity and the F cavity. The P oil port, the P2 oil port, and the P3 oil port are communicated with each other, and the T2 oil port and the T1 oil port are both oil drain ports.

[0009] When the oil enters the P port of the valve body, it enters the P2 and P3 ports at the same time through the internal oil passage. When the pilot solenoid valve is in the middle position, the P2 and P3 ports are in the cut-off state. The oil enters the left end of the control piston through the oil passage J with a delay, pushing the control piston to the right to overcome the spring force, and overflowing the oil to the P4 port. At this time, the system is in a lower pressure state;

[0010] When the pilot solenoid valve YV1 electromagnet is energized, the P3 oil port is connected to the A2 oil port, and part of the oil enters the E chamber of the valve body, pushing the reversing valve core to the right, so that the P2 oil port is connected to the A1 oil port and the K1 oil port. The oil in the A1 oil port enters the first gear clutch, and the oil in the K1 oil port enters the H chamber, pushing the delay piston to the left, compressing the spring group, so that the pressure of the P oil port, P2 oil port, and P3 oil port is increased to the set working pressure of the clutch, and the first gear clutch works normally; when the pilot solenoid valve YV1 electromagnet loses power, the pilot solenoid valve returns to the middle position, the E chamber is depressurized, and under the action of the positioning springs at both ends, the reversing valve core returns to the middle position, and the first gear clutch is quickly disengaged;

[0011] When the pilot solenoid valve YV2 electromagnet is energized, the P3 oil port is connected to the B2 oil port, and part of the oil enters the F chamber of the valve body, pushing the reversing valve core to the left, so that the P2 oil port and the B1 oil port and the K1 oil port, the oil in the B1 oil port enters the second-speed clutch, and the oil in the K1 oil port enters the H chamber, pushing the delay piston to the left, compressing the spring group, so that the pressure of the P oil port, P2 oil port, and P3 oil port increases to the set working pressure of the clutch, and the second-speed clutch works normally; when the pilot solenoid valve YV2 electromagnet loses power, the pilot solenoid valve returns to the middle position, the F chamber is depressurized, and under the action of the positioning springs at both ends, the reversing valve core returns to the middle position, and the second-speed clutch is quickly disengaged.

[0012] As a preferred solution: the K1 oil port is connected to the H chamber through the oil channel Q provided in the valve body. The oil channel Q includes an oil inlet channel Q1 and an oil return channel Q2. A one-way valve is also provided in the oil return channel Q2. When the pilot solenoid valve YV1 electromagnet or YV2 electromagnet loses power, the oil in the H chamber also quickly returns to the T1 oil port through the one-way valve to relieve pressure, causing the delayed piston to move quickly to the right, and the system pressure returns to the lower pressure state when the pilot solenoid valve is in the neutral position.

[0013] As a preferred solution: a throttle valve is provided in the oil inlet passage Q1, and the oil at the K1 oil port enters the H chamber through the throttle valve. Under the action of the throttle valve, the delay piston is slowly pushed to the left, further compressing the spring group, so that the pressure at the P oil port, P2 oil port, and P3 oil port is gradually increased to the set working pressure of the clutch.

[0014] As a preferred solution: the gear reversing slide valve assembly also includes a positioning spring and a plug screw, the two plug screws are respectively fixed at the two ends of the valve body, the two ends of the reversing valve core are respectively resisted against the plug screws through the positioning springs, and the reversing valve core is provided with a protrusion. As the reversing valve core moves, the protrusion connects the corresponding oil port.

[0015] As a preferred solution: the pilot solenoid valve is a three-position four-way solenoid valve with an emergency button.

[0016] As a preferred solution: the pressure control valve assembly also includes a spring seat, which is arranged in the valve body. The delay piston is arranged on one side of the spring seat through a high-pressure large spring and a high-pressure small spring that are nested with each other, and the control piston is arranged on the other side of the spring seat through a low-pressure large spring and a low-pressure small spring that are nested with each other.

[0017] As a preferred solution: a high-pressure adjustment gasket is provided between the spring seat and the high-pressure large spring and the high-pressure small spring, and a low-pressure adjustment gasket is provided between the spring seat and the low-pressure large spring and the low-pressure small spring.

[0018] As a preferred solution: end covers A and B are fixed to both ends of the valve body respectively, an H cavity is formed between the end face of the delay piston and the end cover A, and a P1 cavity is formed between the end face of the control piston and the end cover B.

[0019] As a preferred solution: the oil passage J is opened in the control piston, and a damping screw is further provided in the oil passage J at the end surface of the control piston.

[0020] As a preferred solution: a first sealing gasket and a second sealing gasket are respectively provided at the upper and lower ends of the valve body, and a cover plate is further provided at the upper end of the valve body, and the pilot solenoid valve is fixed on the cover plate.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The method of the present invention uses a low-flow electromagnetic reversing valve as a pilot valve (controlling a three-position, five-way reversing spool valve). The electromagnetic reversing valve, pressure control valve, and gear reversing spool valve are connected via internal oil circuits to form an integrated structure. This structure is easy to install, compact, lightweight, and provides fast response. A throttle valve and a check valve are incorporated into the valve body to control the clutch engagement and disengagement pressure curves, minimizing load startup shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings in the specification, which constitute a part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation on this application.

[0024] Figure 1 Schematic diagram of the electro-hydraulic control principle in the method of the present invention;

[0025] Figure 2 This is one of the overall structural diagrams of the control valve used in the method of the present invention;

[0026] Figure 3 This is the second schematic diagram of the overall structure of the control valve used in the method of the present invention;

[0027] Figure 4 This is a schematic diagram of the side structure of the control valve of the present invention;

[0028] Figure 5 for Figure 4 DD cross-sectional view (rotated 180°);

[0029] Figure 6 It is a structural schematic diagram of the lower end surface of the present invention;

[0030] Figure 7 for Figure 6 GG cross-sectional view;

[0031] The following are marked: 1. Pilot solenoid valve; 2. Shift reversing slide valve assembly; 3. Pressure control valve assembly; 4. Throttle valve; 5. Check valve; 6. Cover plate; 7. First sealing gasket; 8. Valve body; 9. Second sealing gasket; 10. Washer; 11. Positioning spring; 12. Paper gasket A; 13. End cover A; 14. High-pressure large spring B; 15. High-pressure small spring B; 16. Delay piston; 17. High-pressure adjustment gasket; 18. Spring seat; 19. Low-pressure adjustment gasket; 20. Low-pressure small spring A. 21. Low-pressure large spring A; 22. Paper gasket B; 23. End cover B; 24. Control piston; 25. Damping screw; 26. Plug; 27. Reversing valve core; 271. Bump; 800, P oil port; 801, E chamber; 802, F chamber; 803, H chamber; 804, Oil channel J; 805, P1 chamber; 806, P4 oil port; 808, Oil channel Q; 809, T2 oil port; 810, A1 oil port; 811, P2 oil port; 812, K1 oil port; 813, B1 oil port. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] In addition, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0036] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0039] like Figures 1 to 7The control method of an electro-hydraulic control valve is shown. The electro-hydraulic control valve includes a pilot solenoid valve 1, a gear reversing spool valve assembly 2, a pressure control valve assembly 3, and a valve body 8. The pilot solenoid valve 1 is a three-position, four-way solenoid valve with an emergency button. The gear reversing spool valve assembly 2 and the pressure control valve assembly 3 are arranged side by side within the valve body 8. The pilot solenoid valve 1 is arranged above the gear reversing spool valve assembly 2. The valve body 8 is provided with a P oil port 800, an E cavity 801, and an F cavity 802 for oil inlet. The E cavity 801 and the F cavity 802 are respectively located at the two ends of the gear reversing slide valve assembly 2. The valve body 8 is located in the middle of the gear reversing slide valve assembly 2 and is further provided with a T2 oil port 809, an A1 oil port 810, a K1 oil port 812, a P2 oil port 811, a K1 oil port 812, a B1 oil port 813, and a T2 oil port 809. The A1 oil port 810 and the B1 oil port 813 are respectively connected to the first gear clutch and the second gear clutch. The valve body 8 is further provided with a P1 cavity 805 and an H cavity 803 on both sides, and the P1 cavity 805 and the H cavity 803 are connected to the first gear clutch and the second gear clutch. 03 are respectively located at both ends of the pressure control valve assembly 3, the K1 oil port 812 is connected to the H cavity 803, the P oil port 800 is connected to the P1 cavity 805 through the oil channel J804 on the pressure control valve assembly 3, and the pilot solenoid valve 1 is provided with an A2 oil port, a B2 oil port, a T1 oil port and a P3 oil port. The A2 oil port and the B2 oil port are connected to the E cavity 801 and the F cavity 802 respectively. The P oil port 800, the P2 oil port 811 and the P3 oil port are connected to each other, and the T2 oil port 809 and the T1 oil port are both oil drain ports.

[0040] The gear reversing spool valve assembly 2 includes a reversing valve core 27, a positioning spring 11, and a screw plug 26. Two screw plugs 26 are fixed to each end of the valve body 8. The two ends of the reversing valve core 27 are respectively supported by the positioning springs 11 and the screw plugs 26. A gasket 10 is provided between the positioning spring 11 and the reversing valve core 27. The reversing valve core 27 is provided with a bump 271. As the reversing valve core 27 moves, the bump 271 connects the corresponding oil port. When the pilot solenoid valve 1 is in the neutral position, the reversing valve core 27 is in the middle position due to the positioning springs 11 at both ends.

[0041] The pressure control valve assembly 3 includes a spring seat 18, a delay piston 16, and a control piston 24. The spring seat 18 is disposed within the valve body 8. The delay piston 16 is positioned on one side of the spring seat 18 via a nested high-pressure large spring 14 and a nested high-pressure small spring 15. The control piston 24 is positioned on the other side of the spring seat 18 via a nested low-pressure large spring 21 and a nested low-pressure small spring 20. The low-pressure large spring 21, the low-pressure small spring 20, and the high-pressure large spring 14 and the high-pressure small spring 15 form a series spring assembly via the spring seat 18. The diameter of the delay piston 16 is larger than that of the control piston 24.

[0042] End caps A13 and B23 are fixed to both ends of the valve body 8. An H cavity 803 is formed between the end face of the delay piston 16 and end cap A13, and a P1 cavity 805 is formed between the end face of the control piston 24 and end cap B23. Paper gaskets A12 and B22 are respectively installed between the end caps A13 and B23 and the valve body 8.

[0043] A high-pressure adjustment gasket 17 is provided between the spring seat 18 and the high-pressure large spring 14 and the high-pressure small spring 15 , and a low-pressure adjustment gasket 19 is provided between the spring seat 18 and the low-pressure large spring 21 and the low-pressure small spring 20 .

[0044] The oil passage J804 is opened in the control piston 24 , and a damping screw 25 is further provided in the oil passage J at the end surface of the control piston 24 .

[0045] The K1 oil port 812 is connected to the H cavity 803 through the oil channel Q set in the valve body 8. The oil channel Q includes an oil inlet channel Q1 and an oil return channel Q2. A throttle valve 4 is provided in the oil inlet channel Q1, and a one-way valve 5 is also provided in the oil return channel Q2.

[0046] The upper and lower ends of the valve body 8 are respectively provided with a first sealing gasket 7 and a second sealing gasket 9 , and the upper end of the valve body 8 is further provided with a cover plate 6 , and the pilot solenoid valve 1 is fixed on the cover plate 6 .

[0047] The specific control process of the electro-hydraulic control valve in the present invention is as follows: after the oil enters the P oil port of the valve body 8, it enters the P2 and P3 oil ports at the same time through the internal oil channel. When the pilot solenoid valve 1 is in the middle position, the P2 and P3 oil ports are in the cut-off state, and the oil enters the left end of the control piston 24 through the oil channel J and the damping screw 25 with a delay. When the pressure is greater than the set spring force, the control piston 24 is pushed to the right, and the oil overflows to the P4 oil outlet. At this time, the system is in a lower pressure state.

[0048] When the electromagnet of the pilot solenoid valve 1YV1 is energized, P3 is connected to the A2 oil port, and part of the oil enters the E chamber of the valve body 8, pushing the reversing valve core 27 to the right, so that the P2 oil port is connected to the A1 oil port and the K1 oil port (at this time, the P2 oil port and the B1 oil port are cut off), and the oil in the A1 oil port enters the first gear clutch, and the oil in the K1 oil port enters the H chamber through the throttle valve 4. Under the action of the throttle valve 4, the delay piston 16 is slowly pushed to the left, further compressing the spring group, gradually making the P oil port, P2 oil port, and P3 oil port The pressure of (three-port connection) gradually increases to the set working pressure of the clutch, and the first-gear clutch works normally; when the electromagnet of the pilot solenoid valve 1YV1 loses power, the pilot solenoid valve 1 returns to the middle position, the E chamber is depressurized, and under the action of the positioning springs 11 at both ends, the reversing valve core 27 returns to the middle position, and the first-gear clutch is quickly disengaged; at the same time, the oil in the H chamber also quickly returns to the T1 oil port through the one-way valve 5 to relieve pressure, the delay piston 16 quickly moves to the right, and the system pressure returns to the lower pressure state when the pilot solenoid valve 1 is in the middle position.

[0049] When the electromagnet of the pilot solenoid valve 1YV2 is energized, P3 is connected to B2 oil port, and part of the oil enters the F chamber of the valve body 8, pushing the reversing valve core 27 to the left, so that the P2 oil port is connected to the B1 oil port and the K1 oil port (at this time, the P2 oil port and the A1 oil port are cut off), and the oil in the B1 oil port enters the second gear clutch, and the oil in the K1 oil port enters the H chamber through the throttle valve 4. Under the action of the throttle valve 4, the delay piston 16 is slowly pushed to the left, further compressing the spring group, gradually making the P oil port, P2 oil port, and P3 oil port connected. The pressure of (three-port connection) gradually increases to the set working pressure of the clutch, and the second-gear clutch works normally; when the electromagnet of the pilot solenoid valve 1YV2 loses power, the pilot solenoid valve 1 returns to the middle position, the F chamber is depressurized, and under the action of the positioning springs 11 at both ends, the reversing valve core 27 returns to the middle position, and the second-gear clutch is quickly disengaged; at the same time, the oil in the H chamber also quickly returns to the T1 oil port through the one-way valve 5 to relieve pressure, the delay piston 16 quickly moves to the right, and the system pressure returns to the lower pressure state when the pilot solenoid valve 1 is in the middle position.

[0050] The power shift electro-hydraulic control valve used in the method of the present invention is always in a low-pressure state when no shift operation is performed. The system pressure is increased to a set value only when a certain gear clutch is engaged, thereby reducing the energy loss of the prime mover.

[0051] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0052] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are illustrative and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A control method for an electro-hydraulic control valve, characterized in that: The electro-hydraulic control valve comprises a pilot solenoid valve (1), a gear reversing slide valve assembly (2), a pressure control valve assembly (3) and a valve body (8). The gear reversing slide valve assembly (2) and the pressure control valve assembly (3) are arranged side by side in the valve body (8). The pilot solenoid valve (1) is arranged on the upper part of the gear reversing slide valve assembly (2). The gear reversing slide valve assembly (2) comprises a reversing valve core (27) whose two ends are connected to the valve body (8) by springs. The pressure control valve assembly (3) comprises a control piston (24) and a delay piston (16) arranged in the valve body (8) by a spring. The valve body (8) is provided with a P oil port (800), a P4 oil port (806), an E cavity (801) and an F cavity (802) for oil inlet. The E cavity (801) and the F cavity (802) are respectively located at the two ends of the gear reversing slide valve assembly (2). The valve body (8) is further provided with a T2 oil port (809), an A1 oil port (810), a K1 oil port (812), a P2 oil port (811), a K1 oil port (812), a B1 oil port (813), and a T2 oil port (809) in the middle of the gear reversing slide valve assembly (2). The A1 oil port (810) and the B1 oil port (813) are respectively connected to the first gear clutch and the second gear clutch. The valve body (8) is further provided with a P1 cavity (805) and an H cavity (803) on both sides, and the P1 cavity (805) and H cavity (803) are located at both ends of the pressure control valve assembly (3), respectively. The K1 oil port (812) is communicated with the H cavity (803), and the P oil port (800) is communicated with the P1 cavity (805) through the oil passage J (804) on the pressure control valve assembly (3). The pilot solenoid valve (1) is provided with an A2 oil port, a B2 oil port, a T1 oil port and a P3 oil port. The A2 oil port and the B2 oil port are connected to the E cavity (801) and the F cavity (802) respectively. The P oil port (800), the P2 oil port (811) and the P3 oil port are communicated with each other. The T2 oil port (809) and the T1 oil port are both oil drain ports. When the oil enters the P oil port (800) of the valve body (8), it enters the P2 oil port (811) and the P3 oil port at the same time through the internal oil channel. When the pilot solenoid valve (1) is in the middle position, the P2 oil port (811) and the P3 oil port are in the cut-off state. The oil enters the left end of the control piston (24) through the oil channel J (804) with a delay, pushing the control piston (24) to overcome the spring force and move right, causing the oil to overflow to the P4 oil port (806). At this time, the system is in a lower pressure state; When the YV1 electromagnet of the pilot solenoid valve (1) is energized, the P3 oil port is connected to the A2 oil port, and part of the oil enters the E chamber (801) of the valve body (8), pushing the reversing valve core (27) to the right, so that the P2 oil port (811) is connected to the A1 oil port (810) and the K1 oil port (812). The oil in the A1 oil port (810) enters the first gear clutch, and the oil in the K1 oil port (812) enters the H chamber (803), pushing the delay piston ( 16) Move left, compress the spring group, so that the pressure of the P oil port (800), P2 oil port (811), and P3 oil port increases to the set working pressure of the clutch, and the first gear clutch works normally; when the YV1 electromagnet of the pilot solenoid valve (1) loses power, the pilot solenoid valve (1) returns to the middle position, the E chamber (801) is depressurized, and under the action of the positioning springs (11) at both ends, the reversing valve core (27) returns to the middle position, and the first gear clutch is quickly disengaged; When the YV2 electromagnet of the pilot solenoid valve (1) is energized, the P3 oil port is connected to the B2 oil port, and part of the oil enters the F chamber (802) of the valve body (8), pushing the reversing valve core (27) to the left, so that the oil in the P2 oil port (811) and the B1 oil port (813) and the K1 oil port (812) enter the second-speed clutch, and the oil in the K1 oil port (812) enters the H chamber (803), pushing the delay piston (16) to the left, compressing the spring group, so that the pressure of the P oil port (800), P2 oil port (811), and P3 oil port is increased to the set working pressure of the clutch, and the second-speed clutch works normally; when the YV2 electromagnet of the pilot solenoid valve (1) is de-energized, the pilot solenoid valve (1) returns to the middle position, the F chamber (802) is depressurized, and under the action of the positioning springs (11) at both ends, the reversing valve core (27) returns to the middle position, and the second-speed clutch is quickly disengaged.

2. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The K1 oil port (812) is connected to the H chamber (803) through the oil channel Q provided in the valve body (8). The oil channel Q includes an oil inlet channel Q1 and an oil return channel Q2. A one-way valve (5) is also provided in the oil return channel Q2. When the YV1 electromagnet or the YV2 electromagnet of the pilot solenoid valve (1) loses power, the oil in the H chamber (803) also quickly returns to the T1 oil port through the one-way valve (5) to relieve pressure. The delay piston (16) quickly moves to the right, and the system pressure returns to the lower pressure state when the pilot solenoid valve (1) is in the neutral position.

3. The control method of an electro-hydraulic control valve according to claim 2, characterized in that: A throttle valve (4) is provided in the oil inlet passage Q1. The oil from the K1 oil port (812) enters the H chamber (803) through the throttle valve (4). Under the action of the throttle valve (4), the delay piston (16) is slowly pushed to the left, further compressing the spring assembly, so that the pressure of the P oil port (800), the P2 oil port (811), and the P3 oil port is gradually increased to the set working pressure of the clutch.

4. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The gear reversing slide valve assembly (2) further includes a positioning spring (11) and a screw plug (26). The two screw plugs (26) are respectively fixed to the two ends of the valve body (8). The two ends of the reversing valve core (27) are respectively abutted against the screw plugs (26) through the positioning springs (11). The reversing valve core (27) is provided with a protrusion (271). As the reversing valve core (27) moves, the protrusion (271) causes the corresponding oil port to be connected.

5. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The pilot solenoid valve (1) is a three-position four-way solenoid valve with an emergency button.

6. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The pressure control valve assembly (3) further comprises a spring seat (18), wherein the spring seat (18) is arranged in the valve body (8), the delay piston (16) is arranged on one side of the spring seat (18) via a high-pressure large spring (14) and a high-pressure small spring (15) which are mutually sleeved, and the control piston (24) is arranged on the other side of the spring seat (18) via a low-pressure large spring (21) and a low-pressure small spring (20) which are mutually sleeved.

7. The control method of an electro-hydraulic control valve according to claim 6, characterized in that: A high-pressure adjustment gasket (17) is provided between the spring seat (18) and the high-pressure large spring (14) and the high-pressure small spring (15), and a low-pressure adjustment gasket (19) is provided between the spring seat (18) and the low-pressure large spring (21) and the low-pressure small spring (20).

8. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: An end cover A (13) and an end cover B (23) are fixed to both ends of the valve body (8), an H cavity (803) is formed between the end surface of the delay piston (16) and the end cover A (13), and a P1 cavity (805) is formed between the end surface of the control piston (24) and the end cover B (23).

9. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The oil passage J (804) is opened in the control piston (24), and a damping screw (25) is also provided in the oil passage J at the end surface of the control piston (24).

10. The control method of an electro-hydraulic control valve according to claim 1, characterized in that: The upper and lower ends of the valve body (8) are respectively provided with a first sealing gasket (7) and a second sealing gasket (9), and the upper end of the valve body (8) is also provided with a cover plate (6), and the pilot solenoid valve (1) is fixed on the cover plate (6).

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