Combined hydraulic valve

Abstract

The combined hydraulic valve comprises a hydraulic valve body, a mounting cavity communicated with a pressure oil way is formed in the side, located at an oil outlet, of the hydraulic valve body, an electric push rod is detachably fixed in the mounting cavity, and a cleaning assembly is mounted at the piston rod end of the electric push rod; the cleaning assembly comprises a push plate, a cleaning sponge and a movable block, the peripheral side of the push plate slidably abuts against the inner wall of the pressure oil way, the push plate, the cleaning sponge, the movable block and other structures are adopted, the effect of cleaning the pressure oil way multiple times in the process of discharging accumulated liquid at a time is achieved, oil stains are effectively removed, oil stain residues are avoided, and the service life of the pressure oil way is prolonged. Therefore, the effect of reducing internal abrasion of the pressure oil way is achieved, and the combined hydraulic valve is well protected. Meanwhile, the driving structure for driving the cleaning assembly to move through the electric push rod is simpler, the tail end of the electric push rod is located outside the hydraulic valve body, and the electric push rod and the cleaning assembly are convenient to mount, dismount and maintain.

Description

Technical Field

[0001] The present invention relates to a hydraulic valve, and in particular to a combined hydraulic valve applied in the field of hydraulic valves. Background Art

[0002] The combined hydraulic valve is mainly composed of a valve body, a control pilot valve, a filter, a needle valve, a ball valve and a bypass pipe throttling part; it is suitable for equipment and piping systems that need to reduce the temperature of water and non-corrosive liquids (gasoline, kerosene) and gases to a certain range, and can reduce the inlet pressure to a certain required outlet pressure value by adjustment; it plays a great role in controlling the on-off of the oil, gas and water pipeline systems of hydropower stations; traditional hydraulic valves have the problem of liquid accumulation and cannot completely discharge the liquid, so that the liquid accumulates in the valve body, which is easy to cause oxidation corrosion inside the hydraulic valve over time, affecting the service life of the hydraulic valve; therefore, there is an urgent need for a combined hydraulic with anti-liquid accumulation function.

[0003] The specification of Chinese patent CN114484015B discloses a combined hydraulic valve with a function of preventing liquid accumulation, and the invention relates to the technical field of hydraulic valves; an oil inlet pipe is fixedly connected to the oil inlet end of the hydraulic valve body; a pressure oil circuit is provided inside the hydraulic valve body, and the pressure oil circuit is connected in a through-connection manner with the oil inlet pipe; one end of the connecting pipe is fixedly connected in a through-connection manner with the lower end of the oil inlet pipe, and the other end of the connecting pipe is connected in a through-connection manner with the pressure oil circuit, and an electric control valve is fixedly arranged at the connection between the two; a No. 1 one-way valve is fixedly arranged inside the pressure oil circuit; a discharge pipe is fixedly connected and arranged at the bottom of the connecting pipe, and the discharge pipe is provided with a sealing cover; a liquid accumulation cleaning mechanism is arranged in an installation groove provided in the hydraulic valve on one side of the pressure oil circuit; a switch control mechanism is connected to the liquid accumulation cleaning mechanism and is arranged inside the installation groove, and the combined hydraulic valve with a function of preventing liquid accumulation can conveniently discharge the liquid accumulated inside the hydraulic valve, avoid oxidation corrosion inside the hydraulic valve, and increase the service life of the hydraulic valve.

[0004] Although the above hydraulic valve plays a role in discharging the internal liquid, the problem of oil pollution precipitation generated during actual use is not taken into account during the discharging process. The oil pollution in the pressure oil circuit cannot be completely cleaned during a single discharge. Multiple discharges will cause local wear of the internal pipeline of the hydraulic valve, resulting in more precipitated oil pollution in the oil circuit, affecting the stable operation of the hydraulic valve; in serious cases, it will also cause the hydraulic valve to fail or be damaged; Secondly, the structure of the liquid accumulation cleaning mechanism in the above hydraulic valve is relatively complex and is installed inside the hydraulic valve body, which is inconvenient to install, disassemble and repair. Summary of the invention

[0005] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is how to clean the oil stains in the internal pipeline of the hydraulic valve well, avoid the wear of the internal pipeline, and protect the internal structure of the hydraulic valve.

[0006] In order to solve the above problems, the present invention provides a combined hydraulic valve, including a hydraulic valve body, an oil inlet and an oil outlet are respectively provided at both ends of the hydraulic valve body, the intersection of the oil inlet and the oil outlet is connected through an internal through hole, a closing valve for blocking the internal through hole and a piston rod for driving the closing valve to rise are provided between the oil inlet and the oil outlet, a pressure oil circuit is provided at the lower end of the oil inlet and connected, the oil outlet of the pressure oil circuit is located at the lower end of the piston rod and drives the piston rod to rise and fall, the end of the oil inlet is fixed and connected with an oil inlet pipe, and the lower end of the oil inlet pipe is fixed and closed and connected with an oil return pipe that is also connected with the pressure oil circuit; A mounting cavity connected to the pressure oil circuit is provided on one side of the hydraulic valve body located at the oil outlet, an electric push rod is detachably fixed in the mounting cavity, and a cleaning component is installed at the piston rod end of the electric push rod; The cleaning assembly includes a push plate, a cleaning sponge and a movable block. The peripheral side of the push plate is in sliding contact with the inner wall of the pressure oil circuit. The two ends of the cleaning sponge are respectively pressed against one side of the push plate and one side of the movable block. One side of the movable block is fixed to the piston rod end of the electric push rod. The push plate and the movable block are elastically connected by a compression spring. The compression spring is sleeved on the outside of the movable block. The outside of the compression spring is in sliding contact with the inner wall of the pressure oil circuit. An oil discharge port that penetrates the lower end of the hydraulic valve body is provided at the lower end of the connection between the oil return pipe and the pressure oil circuit, and the width of the push plate is smaller than the diameter of the oil discharge port; A valve group controlled by an external controller is installed in the hydraulic valve body. Multiple solenoid valves in the valve group respectively control the opening and closing of the connection between the return oil pipe and the pressure oil circuit, the connection between the oil inlet and the pressure oil circuit, and the connection between the pressure oil circuit and the oil discharge port.

[0007] In the above-mentioned combined hydraulic valve, the cleaning component is driven by the electric push rod to move linearly in the installation cavity and the pressure oil circuit, so that the accumulated liquid in the pressure oil circuit is sent into the oil inlet pipe through the return oil pipe for repeated use; in this process, the push plate first pushes the accumulated liquid in the pressure oil circuit, and the compression spring slides with the inner wall of the pressure oil circuit so that the attached oil dirt is scraped off. Since the compression spring is spirally coiled for multiple turns, the same position is cleaned multiple times, and then the oil dirt and part of the remaining attached liquid are absorbed by the cleaning sponge, and the movable block cleans the pressure oil circuit for the third time again. When one side of the push plate is pressed against the connecting part of the return oil pipe and the pressure oil circuit, the movable block continues to move forward, and the compression spring is forced to contract, further squeezing out the oil dirt and a small amount of accumulated liquid adsorbed on the cleaning sponge, and discharged from the oil discharge port, completing the cleaning operation of the accumulated liquid and oil dirt in the pressure oil circuit, so that the pressure oil circuit is cleaned multiple times in the process of discharging the accumulated liquid in a single time, effectively removing the oil dirt and avoiding the residual oil dirt, thereby achieving the effect of reducing the internal wear of the pressure oil circuit, and playing a good protective role for the combined hydraulic valve itself; At the same time, the driving structure that uses an electric push rod to drive the cleaning component to move is simpler and easier to maintain.

[0008] As a further supplement to the present application, one end of the installation cavity passes through one side of the hydraulic valve body and forms an opening, the tail end of the electric push rod is located outside the hydraulic valve body, and the peripheral sides of the push plate and the movable block are both in sliding contact with the inner wall of the installation cavity.

[0009] As a further supplement to the present application, the valve group includes a first one-way valve, a second one-way valve and a third one-way valve. The first one-way valve is installed at the connection between the oil inlet and the pressure oil circuit and is opened in one direction into the pressure oil circuit. The second one-way valve is installed at the connection between the pressure oil circuit and the oil discharge port and is opened in one direction into the oil discharge port. The third one-way valve is installed at the connection between the return oil pipe and the pressure oil circuit and is opened in one direction into the return oil pipe.

[0010] As another improvement of the present application, the cleaning assembly includes a sealing cap, a cleaning sponge and a movable block. The sealing cap has a conical cap body, and the sealing cap cover is arranged at the end of the cleaning sponge away from the movable block. The peripheral side of the sealing cap is in sliding contact with the inner wall of the pressure oil circuit, and the end of the cleaning sponge away from the sealing cap is tightly pressed against one side. One side of the movable block is fixed to the piston rod end of the electric push rod. The sealing cap and the movable block are elastically connected by a compression spring, and the compression spring is sleeved on the outside of the movable block. The outside of the compression spring is in sliding contact with the inner wall of the pressure oil circuit.

[0011] As another improvement supplement to the present application, when one side of the blocking cap is pressed against the connection between the return oil pipe and the pressure oil circuit, the one side of the blocking cap closes the connection between the return oil pipe and the pressure oil circuit. At this time, the upper end of the blocking cap seals the upper end pipeline of the pressure oil circuit above the oil drain port.

[0012] As another improvement of the present application, a cleaning liquid inlet port connected to the installation cavity is opened at the lower end of the hydraulic valve body. The cleaning liquid inlet port is located between the push plate and the movable block or the movable block and the sealing cap, and the cleaning liquid inlet port transports cleaning liquid into the installation cavity.

[0013] As a further improvement and supplement of the present application, a fourth one-way valve is installed at the connection point between the cleaning liquid inlet and the installation cavity, and the fourth one-way valve opens in one direction toward the installation cavity.

[0014] As a supplement to another improvement of the present application, a filter is fixed at the connection point between the return oil pipe and the pressure oil circuit, and the filter is located on a side of the third one-way valve close to the electric push rod.

[0015] In summary, in the normal operation of the combined hydraulic valve, the first one-way valve is opened, and the second one-way valve and the third one-way valve are closed at the same time. The oil enters the oil inlet from the oil inlet pipe and is divided into two paths. One path continues to move along the pipeline of the oil inlet to the internal through hole connected to the oil outlet, and the other path moves to the lower end of the piston rod through the pressure oil path, and finally lifts the piston rod, so that the piston rod rises and lifts the closing valve. At this time, the oil inlet and the oil outlet are connected, and one path of oil flows out from the oil outlet; When it is necessary to clean the accumulated liquid in the pressure oil circuit, the first one-way valve must be closed and the third one-way valve must be opened. Then, the electric push rod is used to drive the cleaning component to move linearly in the installation cavity and the pressure oil circuit, so that the accumulated liquid in the pressure oil circuit is sent to the oil inlet pipe through the return oil pipe for reuse. In this process, the push plate first pushes the accumulated liquid in the pressure oil circuit, and the compression spring slides with the inner wall of the pressure oil circuit so that the attached oil is scraped off. Since the compression spring spirally coils for multiple turns, the same position will be cleaned multiple times. After that, the oil and some of the remaining attached liquid are absorbed by the cleaning sponge, and the movable block again cleans the pressure oil. The third cleaning of the oil circuit is carried out. When one side of the push plate is pressed against the connecting part between the oil return pipe and the pressure oil circuit, the third one-way valve is closed and the second one-way valve is opened. At this time, the movable block continues to move forward, and the compression spring is forced to contract, further squeezing out the oil and a small amount of accumulated liquid adsorbed on the cleaning sponge and discharged from the oil discharge port, completing the cleaning of the accumulated liquid and oil in the pressure oil circuit. In this way, the pressure oil circuit is cleaned multiple times in the process of discharging the accumulated liquid in a single time, effectively removing the oil and avoiding the residual oil, thereby achieving the effect of reducing the internal wear of the pressure oil circuit, and playing a good protective role for the combined hydraulic valve itself. At the same time, the driving structure of using an electric push rod to drive the cleaning component to move is simpler, and the tail end of the electric push rod is located outside the hydraulic valve body, which is convenient for installing, disassembling and maintaining the electric push rod and the cleaning component. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional view of the overall structure of the first embodiment of the present application; Figure 2 for Figure 1 A magnified view of the structure at center; Figure 3 This is a schematic diagram of the cleaning component structure of the first embodiment of the present application; Figure 4 This is a schematic diagram of the cleaning component structure of the second embodiment of the present application; Figure 5 This is a cross-sectional view of the overall structure of the third embodiment of the present application; Figure 6 This is a schematic diagram of the oil flow direction of the first embodiment of the present application; Figure 7 This is a schematic diagram of the oil return flow direction of the first embodiment of the present application; Figure 8 This is a schematic diagram of the sealing relationship formed between the sealing cap, the oil return pipe and the pressure oil circuit in the second embodiment of the present application.

[0017] Description of the numbers in the figure: 1. Hydraulic valve body; 11. Oil inlet; 12. Oil outlet; 13. Pressure oil circuit; 14. Oil drain; 15. Installation cavity; 16. Cleaning liquid inlet; 2. Oil inlet pipe; 3. Piston rod; 4. Closing valve; 5. Electric push rod; 6. Cleaning component; 61. Push plate; 62. Cleaning sponge; 63. Movable block; 64. Compression spring; 65. Sealing cap; 7. Oil return pipe; 8. Valve group; 81. First one-way valve; 82. Second one-way valve; 83. Third one-way valve; 84. Fourth one-way valve; 9. Filter. DETAILED DESCRIPTION

[0018] The following is a detailed description of three implementation methods of the present application in conjunction with the accompanying drawings.

[0019] The first implementation method: The present invention provides a combined hydraulic valve, see Figure 1-Figure 3 , comprising a hydraulic valve body 1, with an oil inlet 11 and an oil outlet 12 respectively provided at both ends of the hydraulic valve body 1, the intersection of the oil inlet 11 and the oil outlet 12 being connected via an internal through hole, a closing valve 4 for blocking the internal through hole and a piston rod 3 for driving the closing valve 4 to rise being provided between the oil inlet 11 and the oil outlet 12, a pressure oil circuit 13 being provided at the lower end of the oil inlet 11, the oil outlet of the pressure oil circuit 13 being located at the lower end of the piston rod 3 and driving the piston rod 3 to rise and fall, an oil inlet pipe 2 being fixedly connected to the end of the oil inlet 11, and an oil return pipe 7 being fixedly closed and connected to the pressure oil circuit 13 at the lower end of the oil inlet pipe 2; The hydraulic valve body 1 is provided with a mounting cavity 15 connected to the pressure oil circuit 13 on one side of the oil outlet 12. An electric push rod 5 is detachably fixed in the mounting cavity 15. A cleaning assembly 6 is installed at the piston rod end of the electric push rod 5. One end of the installation cavity 15 passes through one side of the hydraulic valve body 1 and forms an opening, the rear end of the electric push rod 5 is located outside the hydraulic valve body 1, and the peripheral sides of the push plate 61 and the peripheral sides of the movable block 63 are both in sliding contact with the inner wall of the installation cavity 15; The cleaning assembly 6 includes a push plate 61, a cleaning sponge 62 and a movable block 63. The circumference of the push plate 61 is in sliding contact with the inner wall of the pressure oil circuit 13. The two ends of the cleaning sponge 62 are respectively pressed against one side of the push plate 61 and one side of the movable block 63. One side of the movable block 63 is fixed to the piston rod end of the electric push rod 5. The push plate 61 and the movable block 63 are elastically connected by a compression spring 64. The compression spring 64 is sleeved on the outside of the cleaning sponge 62. The outside of the compression spring 64 is in sliding contact with the inner wall of the pressure oil circuit 13. The lower end of the connection between the return oil pipe 7 and the pressure oil circuit 13 is provided with an oil discharge port 14 penetrating the lower end of the hydraulic valve body 1, and the width of the push plate 61 is smaller than the diameter of the oil discharge port 14; A valve group 8 controlled by an external controller is installed in the hydraulic valve body 1. Multiple solenoid valves in the valve group 8 respectively control the opening and closing of the connection between the return oil pipe 7 and the pressure oil circuit 13, the connection between the oil inlet 11 and the pressure oil circuit 13, and the connection between the pressure oil circuit 13 and the oil discharge port 14. The valve group 8 includes a first one-way valve 81, a second one-way valve 82 and a third one-way valve 83. The first one-way valve 81 is installed at the connection between the oil inlet 11 and the pressure oil circuit 13 and is opened in one direction into the pressure oil circuit 13. The second one-way valve 82 is installed at the connection between the pressure oil circuit 13 and the oil discharge port 14 and is opened in one direction into the oil discharge port 14. The third one-way valve 83 is installed at the connection between the return oil pipe 7 and the pressure oil circuit 13 and is opened in one direction into the return oil pipe 7.

[0020] Based on the above structure, in the normal operation of the combined hydraulic valve, the first one-way valve 81 is opened, and the second one-way valve 82 and the third one-way valve 83 are closed at the same time, and the oil enters the oil inlet 11 from the oil inlet pipe 2 and is divided into two paths, one path continues to move along the pipeline of the oil inlet 11 to the internal through hole connected to the oil outlet 12, and the other path moves to the lower end of the piston rod 3 through the pressure oil path 13, and finally lifts the piston rod 3, so that the piston rod 3 rises and lifts the closing valve 4. At this time, the oil inlet 11 and the oil outlet 12 are connected, and one path of oil flows out from the oil outlet 12; When it is necessary to clean the accumulated liquid in the pressure oil circuit 13, the first one-way valve 81 needs to be closed first, and the third one-way valve 83 needs to be opened. Then, the cleaning assembly 6 is driven by the electric push rod 5 to move linearly in the installation cavity 15 and the pressure oil circuit 13, so that the accumulated liquid in the pressure oil circuit 13 is sent to the oil inlet pipe 2 through the return oil pipe 7 for repeated use. In this process, the push plate 61 first pushes the accumulated liquid in the pressure oil circuit 13, and the compression spring 64 slides with the inner wall of the pressure oil circuit 13 so that the attached oil is scraped off. Since the compression spring 64 spirally rotates for multiple turns, the same position will be cleaned multiple times. After that, the oil and part of the remaining attached liquid are absorbed by the cleaning sponge 62, and the movable block 63 is used again. The pressure oil circuit 13 is cleaned for the third time. When one side of the push plate 61 is pressed against the connection between the return oil pipe 7 and the pressure oil circuit 13, the third one-way valve 83 is closed and the second one-way valve 82 is opened. At this time, the movable block 63 continues to move forward, and the compression spring 64 is forced to contract, further squeezing out the oil and a small amount of accumulated liquid adsorbed on the cleaning sponge 62, and discharging them from the oil discharge port 14, completing the cleaning operation of the accumulated liquid and oil in the pressure oil circuit 13, so that the pressure oil circuit 13 can be cleaned multiple times in the process of discharging the accumulated liquid in a single time, effectively removing the oil and avoiding the residual oil, thereby achieving the effect of reducing the internal wear of the pressure oil circuit 13, and playing a good protective role for the combined hydraulic valve itself; At the same time, the driving structure of using the electric push rod 5 to drive the cleaning component 6 to move is simpler, and the tail end of the electric push rod 5 is located outside the hydraulic valve body 1, which is convenient for installing, disassembling and maintaining the electric push rod 5 and the cleaning component 6.

[0021] Second implementation method: Figure 4 Another cleaning component 6 is shown, which is different from Example 1 in that the cleaning component 6 includes a sealing cap 65, a cleaning sponge 62 and a movable block 63. The sealing cap 65 is a conical cap body, and the sealing cap 65 is covered on the end of the cleaning sponge 62 away from the movable block 63. The circumference of the sealing cap 65 is in sliding contact with the inner wall of the pressure oil circuit 13, and the end of the cleaning sponge 62 away from the sealing cap 65 is pressed against one side, and one side of the movable block 63 is fixed to the piston rod end of the electric push rod 5. The sealing cap 65 and the movable block 63 are elastically connected by a compression spring 64. The compression spring 64 is sleeved on the outside of the cleaning sponge 62, and the outside of the compression spring 64 is in sliding contact with the inner wall of the pressure oil circuit 13.

[0022] Figure 8 It is shown that when one side of the blocking cap 65 is pressed against the connection between the return oil pipe 7 and the pressure oil circuit 13, the one side of the blocking cap 65 closes the connection between the return oil pipe 7 and the pressure oil circuit 13. At this time, the upper end of the blocking cap 65 closes the upper end pipeline of the pressure oil circuit 13 located above the oil drain port 14.

[0023] The working method of this embodiment is basically the same as that of Embodiment 1 and will not be described in detail here. The difference between this embodiment and Embodiment 1 is that, through the provision of the blocking cap 65, the oil and a small amount of accumulated liquid squeezed out of the cleaning sponge 62 can be prevented from entering the vertical pipe of the pressure oil circuit 13 upward, thereby avoiding repeated contamination of the vertical pipe of the pressure oil circuit 13 and ensuring that the oil and a small amount of accumulated liquid can enter the oil drain port 14 through the gap and be discharged smoothly.

[0024] The third implementation method: Figure 5 Another combined hydraulic valve is shown, which is based on Example 1 or Example 2. The difference between it and Example 1 or Example 2 is that a cleaning liquid inlet 16 connected to the installation cavity 15 is opened at the lower end of the hydraulic valve body 1, and the cleaning liquid inlet 16 is located between the push plate 61 and the movable block 63 or the movable block 63 and the blocking cap 65. The cleaning liquid inlet 16 transports cleaning liquid into the installation cavity 15, and a fourth one-way valve 84 is installed at the connection between the cleaning liquid inlet 16 and the installation cavity 15. The fourth one-way valve 84 is opened in one direction into the installation cavity 15.

[0025] By setting the cleaning liquid inlet 16 and the fourth one-way valve 84, the cleaning liquid can be transported between the push plate 61 and the movable block 63 or the movable block 63 and the blocking cap 65, so as to dissolve the precipitated oil in the pressure oil circuit 13, thereby achieving a better cleaning effect. At the same time, the cleaning sponge 62 can also be cleaned to achieve the effect of repeated cleaning for a long time.

[0026] Figure 5 It is shown that a filter screen 9 is fixed at the connection point between the return oil pipe 7 and the pressure oil circuit 13 , and the filter screen 9 is located on a side of the third one-way valve 83 close to the electric push rod 5 .

[0027] By setting the filter screen 9, the oil and dirt scraped by the push plate 61 or the blocking cap 65 can be intercepted to prevent it from flowing back into the oil inlet pipe 2 through the return oil pipe 7. During the next operation, the incoming oil will flush the oil and dirt on the filter screen 9, ensuring that the filter screen 9 plays a good intercepting role and is convenient for subsequent cleaning.

[0028] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A combined hydraulic valve, comprising a hydraulic valve body (1), wherein the hydraulic valve body (1) is provided with an oil inlet (11) and an oil outlet (12) at both ends thereof, wherein the intersection of the oil inlet (11) and the oil outlet (12) is connected via an internal through hole, wherein a closing valve (4) for blocking the internal through hole and a piston rod (3) for driving the closing valve (4) to rise are arranged between the oil inlet (11) and the oil outlet (12), wherein a pressure oil circuit (13) is provided at the lower end of the oil inlet (11) and is connected thereto, wherein the oil outlet of the pressure oil circuit (13) is located at the lower end of the piston rod (3) and drives the piston rod (3) to rise and fall, wherein an oil inlet pipe (2) is fixedly connected to the end of the oil inlet (11), wherein the lower end of the oil inlet pipe (2) is fixedly closed and connected to an oil return pipe (7) which is also connected to the pressure oil circuit (13), wherein the combination hydraulic valve comprises: The hydraulic valve body (1) is provided with a mounting cavity (15) on one side of the oil outlet (12) and communicated with the pressure oil circuit (13); an electric push rod (5) is detachably fixed in the mounting cavity (15); a cleaning assembly (6) is installed at the piston rod end of the electric push rod (5); The cleaning assembly (6) comprises a push plate (61), a cleaning sponge (62) and a movable block (63); the circumferential side of the push plate (61) is in sliding contact with the inner wall of the pressure oil circuit (13); the two ends of the cleaning sponge (62) are respectively in tight contact with one side of the push plate (61) and one side of the movable block (63); one side of the movable block (63) is fixed to the end of the piston rod of the electric push rod (5); the push plate (61) and the movable block (63) are elastically connected via a compression spring (64); the compression spring (64) is sleeved on the outside of the cleaning sponge (62); the outside of the compression spring (64) is in sliding contact with the inner wall of the pressure oil circuit (13); An oil discharge port (14) penetrating the lower end of the hydraulic valve body (1) is provided at the lower end of the connection between the oil return pipe (7) and the pressure oil circuit (13); the width of the push plate (61) is smaller than the diameter of the oil discharge port (14); A valve group (8) controlled by an external controller is installed in the hydraulic valve body (1), and a plurality of solenoid valves in the valve group (8) respectively control the opening and closing of a connection point between the oil return pipe (7) and the pressure oil circuit (13), a connection point between the oil inlet (11) and the pressure oil circuit (13), and a connection point between the pressure oil circuit (13) and the oil discharge port (14).

2. A combined hydraulic valve according to claim 1, characterized in that: One end of the installation cavity (15) passes through one side of the hydraulic valve body (1) to form an opening, the rear end of the electric push rod (5) is located outside the hydraulic valve body (1), and the peripheral side of the push plate (61) and the peripheral side of the movable block (63) are both in sliding contact with the inner wall of the installation cavity (15).

3. A combined hydraulic valve according to claim 2, characterized in that: The valve group (8) comprises a first one-way valve (81), a second one-way valve (82) and a third one-way valve (83); the first one-way valve (81) is installed at the connection between the oil inlet (11) and the pressure oil circuit (13) and is opened in one direction into the pressure oil circuit (13); the second one-way valve (82) is installed at the connection between the pressure oil circuit (13) and the oil discharge port (14) and is opened in one direction into the oil discharge port (14); and the third one-way valve (83) is installed at the connection between the oil return pipe (7) and the pressure oil circuit (13) and is opened in one direction into the oil return pipe (7).

4. A combined hydraulic valve according to claim 1, characterized in that: The cleaning assembly (6) comprises a blocking cap (65), a cleaning sponge (62) and a movable block (63); the blocking cap (65) is a conical cap body; the blocking cap (65) is arranged to cover the end of the cleaning sponge (62) away from the movable block (63); the peripheral side of the blocking cap (65) is in sliding contact with the inner wall of the pressure oil circuit (13); the end of the cleaning sponge (62) away from the blocking cap (65) is tightly pressed against one side; one side of the movable block (63) is fixed to the end of the piston rod of the electric push rod (5); the blocking cap (65) and the movable block (63) are elastically connected via a compression spring (64); the compression spring (64) is sleeved on the outside of the cleaning sponge (62); the outside of the compression spring (64) is in sliding contact with the inner wall of the pressure oil circuit (13).

5. A combined hydraulic valve according to claim 4, characterized in that: When one side of the blocking cap (65) is pressed against the connection between the oil return pipe (7) and the pressure oil circuit (13), the one side of the blocking cap (65) closes the connection between the oil return pipe (7) and the pressure oil circuit (13). At this time, the upper end of the blocking cap (65) closes the upper end pipeline of the pressure oil circuit (13) located above the oil discharge port (14).

6. A combined hydraulic valve according to any one of claims 1 or 4, characterized in that: The lower end of the hydraulic valve body (1) is provided with a cleaning liquid inlet (16) which is in communication with the mounting cavity (15); the cleaning liquid inlet (16) is located between the push plate (61) and the movable block (63) or between the movable block (63) and the blocking cap (65); the cleaning liquid inlet (16) transports cleaning liquid into the mounting cavity (15).

7. A combined hydraulic valve according to claim 6, characterized in that: A fourth one-way valve (84) is installed at the connection point between the cleaning liquid inlet (16) and the installation cavity (15), and the fourth one-way valve (84) opens in one direction toward the installation cavity (15).

8. A combined hydraulic valve according to claim 7, characterized in that: A filter screen (9) is fixed at the connection point between the oil return pipe (7) and the pressure oil circuit (13), and the filter screen (9) is located on a side of the third one-way valve (83) close to the electric push rod (5).

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