A pilot-controlled commutation loop with fast reset

Abstract

The application belongs to the technical field of hydraulic control, and discloses a pilot control reversing circuit with quick reset, which comprises an oil pump unit, a pilot control valve, a quick reset unit and a main reversing valve. The quick reset unit comprises a cylinder body and a piston with a through hole in the center. The first end surface of the cylinder body is provided with an oil inlet P, and the second end surface is provided with a main connection port A. The side wall of the cylinder body is provided with an oil return port T near the second end surface. When the pilot control valve is opened, the pressure oil flows into the cylinder body through the oil inlet P and pushes the piston to move to abut against the second end surface. The pressure oil flows into the main reversing valve through the through hole and the main connection port A to push the main reversing valve to reverse. When the pilot control valve is closed, the pressure oil flows back to the cylinder body and pushes the piston to separate from the second end surface, so that the oil return port T is opened, the pressure oil flows out through the oil return port T, and the main reversing valve is reset. The main reversing valve is not affected by the small diameter of the pilot control valve, so as to quickly reset, improve the working efficiency and reliability, and widen the application range of the reversing circuit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic control, and more particularly relates to a pilot control reversing circuit with fast reset. BACKGROUND

[0002] The main function of the hydraulic reversing circuit is to change the direction of the liquid flow and the movement direction of the hydraulic actuator, and a reversing valve is generally used to realize the reversing in the hydraulic equipment. The reversing circuit in the hydraulic equipment is a core factor affecting the response speed of the equipment. The reversing valve has the advantages of simple structure, few components, and sensitive reversing, and is widely used in various hydraulic equipment.

[0003] However, in some special fields such as deep space, deep earth, and deep sea, the working environment can change in the range of normal temperature to 200 DEG C and normal pressure to 140 MPa. In addition to the requirement that the hydraulic equipment can work normally in a wide temperature and pressure environment, the hydraulic equipment is also required to have the characteristics of large flow rate, fast response speed, and stable work. At present, there are very few products on the market that can be used in the wide temperature and pressure environment requirements, and the flow diameter of the products is below 2 mm, the application range is very narrow, and they cannot meet the requirements of large flow rate and fast work. Since the viscosity of the liquid medium is greatly affected by the change of the environmental temperature, the liquid resistance of the liquid medium through the small-diameter oil path also changes greatly, resulting in large oil return resistance of the pilot control valve through the small-diameter oil path, which restricts the reset speed of the main reversing valve, and thus restricts the movement speed of the actuator.

[0004] Therefore, it is urgent to develop a reversing circuit capable of improving the reset speed of the reversing valve to solve the problems that the reset speed of the main reversing valve and the movement speed of the actuator are restricted by the small diameter of the pilot control valve, and the application range is limited. SUMMARY

[0005] In view of the problem that the viscosity of the liquid medium changes when the pilot control reversing circuit is used in the environment with changing temperature, the reset speed of the main reversing valve and the movement speed of the actuator are restricted by the small diameter of the pilot control valve, and the application range is limited, the present application provides a pilot control reversing circuit with fast reset, and the purpose is to add a fast reset unit, so that the reset speed of the main reversing valve is not affected by the small diameter of the pilot control valve, the main reversing valve is reset quickly, the working efficiency and reliability of the reversing circuit are improved, and the application range of the hydraulic reversing circuit is widened.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] Provided is a rapid-reset pilot control reversing circuit, comprising an oil pump unit, a pilot control valve, and a main reversing valve, which are sequentially connected via an oil circuit, the oil pump unit being used to supply pressurized oil to the pilot control valve; characterized in that it also comprises a rapid-reset unit connected between the pilot control valve and the main reversing valve; the rapid-reset unit comprising a cylinder body and a piston with a through hole in the center; the first end face of the cylinder body being provided with an oil inlet P connected to the pilot control valve, and the second end face being provided with a main connection port A connected to the main reversing valve; the piston being slidably connected to the inner wall of the cylinder body between the first and second end faces of the cylinder body; the side wall of the cylinder body being provided with an oil return port T near the second end face, the oil return port T being connected to an oil tank;

[0008] When the pilot control valve is opened, the pressure oil flows into the cylinder body through the oil inlet P and pushes the piston to move until it is close to the second end face, so that the pressure oil flows into the main reversing valve through the through hole and the main connecting port A to push the main reversing valve to reverse; when the pilot control valve is closed, the pressure oil in the main reversing valve flows back to the cylinder body and pushes the piston to separate from the second end face, so that the return oil port T is opened, and the pressure oil flows out through the return oil port T to realize the resetting of the main reversing valve.

[0009] Preferably, the rapid reset unit further includes an elastic structure, wherein the elastic structure is provided between the first end surface and the piston, and the elastic structure is in a compressed state.

[0010] Preferably, a first groove is provided on the end face of the piston facing the main connection port A, and a first sealing ring is provided at the first groove. The thickness of the first sealing ring is greater than the depth of the first groove, so that when the piston moves to press against the second end face, there is a gap between the end face of the piston facing the main connection port A and the second end face.

[0011] Preferably, when the pilot control valve is closed, the thrust exerted on the piston by the pressure oil in the main reversing valve is greater than the pre-tightening force of the elastic structure, so that the piston can be pushed to separate from the second end surface.

[0012] Preferably, the axial projection area of ​​the piston is S, and the oil pressure of the pressure oil is p c , the oil pressure of the oil tank is p t , the piston has friction resistance F during the sliding process t , the oil in the cylinder body has an axial fluid force F during the flow process h When the piston is pressed against the second end surface, the pre-compression force F of the elastic structure satisfies the following relationship:

[0013] F <S×(p c -pt )-F f -F h .

[0014] Preferably, the side wall of the piston is provided with a second groove, and a second sealing ring is arranged at the second groove, and the piston is in sliding sealing connection with the cylinder through the second sealing ring.

[0015] Preferably, the pilot control valve comprises a pilot oil inlet, a pilot oil outlet and a pilot return oil port, the pilot oil outlet is selectively communicated with the pilot oil inlet and the pilot return oil port, the oil pump unit is communicated with the pilot oil inlet, the pilot oil outlet is communicated with the oil inlet P, and the pilot return oil port is connected with the oil tank.

[0016] Preferably, the hole diameter of the through hole is equal to the diameter of the pilot oil outlet, the diameter of the oil path is also equal to the diameter of the pilot oil outlet, and the diameter of the return oil port T is greater than the diameter of the pilot oil outlet.

[0017] Preferably, the main reversing valve comprises a valve core and a valve sleeve, the valve sleeve is internally provided with a cavity, the valve core is slidably arranged in the cavity, and the valve core divides the cavity into a control cavity and a moving cavity, the main connection port A is connected with the control cavity through the oil path; the moving cavity comprises a reversing return oil port, and the reversing return oil port is connected with the oil tank.

[0018] Preferably, the linear expansion coefficients of the materials of the valve core and the valve sleeve are consistent.

[0019] Overall, compared with the prior art, the above technical scheme has the following technical effects:

[0020] 1. A pilot control reversing circuit with fast reset is provided, and a fast reset unit is arranged between the pilot control valve and the main reversing valve, so that in the reset process, when the pressure oil flows back to the cylinder, the piston can be pushed away from the second end face to open the return oil port T, so that the pressure oil directly flows out through the return oil port T, the reset speed of the main reversing valve is not affected by the small diameter of the pilot control valve, the main reversing valve can be quickly reset in a wide temperature environment, the working efficiency and reliability of the reversing circuit are improved, and the application range of the hydraulic reversing circuit is widened.

[0021] 2. The elastic structure is arranged between the first end face and the piston and is in a compressed state, so that the piston can be kept in abutting contact with the second end face in the initial state, which is beneficial to the fast response in the initial stage of the reversing process and improves the working stability; the pre-compression force F of the elastic structure is set according to the stress relationship of the piston in the reset process, so that the piston and the second end face can be smoothly separated in the reset process, which is beneficial to the normal work of the fast reset unit.

[0022] 3. The present application sets the aperture of the through hole equal to the through diameter of the pilot oil outlet, so that in the reversing process of the opening of the pilot control valve, the pressure oil flowing through the through hole does not produce additional resistance, and the effective pressure enters the main reversing valve, while in the resetting process of the closing of the pilot control valve, the through hole plays a liquid resistance role when the pressure oil flows through the quick reset unit, the pressure oil in the main reversing valve can generate sufficient back pressure to push the piston to overcome the friction, spring force and other resistance and separate from the second end surface, so that as much pressure oil as possible flows out through the oil return port T with a larger through diameter, which is beneficial to the quick resetting of the main reversing valve;

[0023] 4. The present application sets the pilot return port on the pilot control valve and the reversing return port on the main reversing valve, and connects the oil return port T, the pilot return port and the reversing return port with the oil tank respectively, so that the interiors of each element in the reversing circuit are connected with the external environment, in the working process, the hydraulic pressure of each element in the reversing circuit is the effective pressure to overcome the load, and the pressure of the environment is automatically balanced, realizing stable operation of the reversing circuit in a wide pressure environment and improving its adaptability to the wide pressure environment;

[0024] 5. The present application uses materials with consistent linear expansion coefficients for the valve sleeve and the valve core, so that when the main reversing valve is applied to different temperature conditions, the thermal deformation of the valve sleeve and the valve core caused by temperature change is consistent, which is beneficial to stable cooperation of the valve sleeve and the valve core in different temperature environments, realizing stable operation of the reversing circuit in a wide temperature environment and improving its adaptability to the environmental temperature. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of a quick reset pilot control reversing circuit of the present application;

[0026] Figure 2 is a working process principle diagram of a quick reset pilot control reversing circuit of the present application;

[0027] Figure 3 is a resetting process principle diagram of a quick reset pilot control reversing circuit of the present application;

[0028] Figure 4 is a simple diagram of two working states of a quick reset pilot control reversing circuit of the present application;

[0029] Throughout the drawings, the same reference numerals denote the same components or structures. Since the main reversing valve in the reversing circuit primarily relies on the action of the valve core to achieve reversal, for simplicity, a single-acting hydraulic cylinder is used in the drawings to replace the action of the valve core and the main reversing valve to explain the reversing operating principle. This reversing circuit can be used in control systems with a variety of actuators. For simplicity, a double-acting hydraulic cylinder is used in the drawings to replace the actuators to explain the control process of the reversing circuit, where:

[0030] 1-Oil pump unit, 2-Pilot control valve, 3-Quick reset unit, 4-Main reversing valve, 5-Oil tank, 6-Pilot oil outlet, 7-First oil circuit, 8-Oil inlet P, 9-Cylinder body, 10-Elastic structure, 11-Second sealing ring, 12-Piston, 13-First sealing ring, 14-Gap, 15-Main connection port A, 16-Oil return port T, 17-Third oil circuit, 18-Second oil circuit. DETAILED DESCRIPTION

[0031] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

[0032] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0033] See Figure 1 This embodiment provides a rapid-reset pilot control reversing circuit, comprising an oil pump unit 1, a pilot control valve 2, and a main reversing valve 4, connected sequentially via an oil circuit. It also includes a rapid-reset unit 3 connected between the pilot control valve 2 and the main reversing valve 4. The oil pump unit 1 is used to supply hydraulic oil at the required pressure and flow rate to the reversing circuit. The oil circuit includes a first oil circuit 7, a second oil circuit 18, and a third oil circuit 17. The rapid-reset unit 3 comprises a cylinder 9 and a piston 12 with a central through-hole. The first end surface of the cylinder 9 is provided with an oil inlet P8 connected to the pilot control valve 2 via the first oil circuit 7, and the second end surface is provided with a main connection port A15 connected to the main reversing valve 4 via the second oil circuit 18. The piston 12 is slidably connected to the inner wall of the cylinder 9 between the first and second end surfaces. The side wall of the cylinder 9 is provided with an oil return port T16 near the second end surface. This oil return port T16 is connected to the oil tank 5 via the third oil circuit 17.

[0034] When the pilot control valve 2 is opened, refer to Figure 2The pressure oil flows out of the pilot control valve 2, flows into the cylinder 9 through the oil inlet P8, and pushes the piston 12 to move to the second end face, so that the pressure oil flows out through the through hole and the main connecting port A15, flows into the main reversing valve 4 through the second oil path 18, and pushes the main reversing valve 4 to reverse direction; when the pilot control valve 2 is closed, refer to Figure 3 The main reversing valve 4 is reset by the reset mechanism. The pressurized oil within the main reversing valve 4 flows back into the cylinder 9, generating a significant back pressure, pushing the piston 12 away from the second end face, causing the return oil port T16 to open. The pressurized oil preferentially flows directly back to the oil tank 5 through the larger diameter return oil port T16 and the third oil passage 17. As a result, the main reversing valve 4 is not restricted by the small diameter of the pilot control valve 2 during the reset process. This allows the main reversing valve 4 to quickly reset in a wide range of temperature environments, without affecting its operating performance due to changes in fluid resistance caused by changes in oil viscosity. This improves the ambient temperature adaptability and reliability of the reversing circuit. By cycling through the aforementioned opening and closing steps of the pilot control valve 2, rapid switching and resetting of the main reversing valve 4 is achieved.

[0035] In practical applications, the reversing circuit provided by this embodiment is connected to the actuators in different application requirements. Figure 4 It can realize the rapid reset of the main reversing valve, adapt to the application requirements of various flow and diameter actuators, improve the working efficiency and reliability of the reversing circuit, and broaden the application range of the hydraulic reversing circuit in a wide temperature and pressure environment.

[0036] Specifically, the rapid reset unit 3 further includes an elastic structure 10, one end of which is disposed on the inner wall of the first end surface, and the other end of which is disposed on the end surface of the piston 12 facing the oil inlet P8. The elastic structure 10 is in a compressed state, ensuring that the piston 12 is initially positioned against the second end surface, facilitating a rapid response at the start of the reversing stroke and improving operational stability.

[0037] Specifically, the piston 12 is provided with a first groove at the end face thereof facing the main connection port A15, and a first sealing ring 13 is arranged at the first groove. The thickness of the first sealing ring 13 is greater than the depth of the first groove, so that when the piston 12 is moved to abut against the second end face, a gap 14 is formed between the end face of the piston 12 facing the main connection port A15 and the second end face, so that the oil pressure of the pressure oil acts on the end face of the piston 12 facing the main connection port A15 during the resetting process, and pushes the piston 12 away from the second end face. Meanwhile, the gap 14 is beneficial to buffer the oil pressure impact and improve the working safety. The first sealing ring 13 is used to prevent the radial leakage of the pressure oil when the piston 12 abuts against the second end face, and can be made of an axial O-shaped sealing ring made of high-temperature-resistant rubber material, or other high-temperature-resistant sealing materials, which are not limited herein. The groove between the first sealing ring 13 and the first groove can be designed in a dovetail shape to fix the sealing ring, or other special-shaped groove designs, which are not limited herein.

[0038] Specifically, when the pilot control valve 2 is closed, the pushing force of the pressure oil in the main reversing valve 4 on the piston 12 is greater than the pre-compression force of the elastic structure 10, so that the piston 12 can be pushed away from the second end face.

[0039] Specifically, the axial projection area of the piston 12 is S, the oil pressure of the pressure oil is p c , the oil pressure of the oil tank 5 is p t , the friction resistance of the piston 12 during sliding is F t , and the axial hydrodynamic force of the oil in the cylinder body 9 during flowing is F h When the piston 12 abuts against the second end face, the pre-compression force F of the elastic structure 10 satisfies the following relationship:

[0040] F < S × (p c -p t )-F f -F h ,

[0041] The piston 12 and the second end face are smoothly separated during the resetting process, which is beneficial to the normal operation of the quick resetting unit 3.

[0042] Specifically, the side wall of the piston 12 is provided with a second groove, and a second sealing ring 11 is arranged at the second groove. The piston 12 and the cylinder body 9 are connected in a sliding sealing manner through the second sealing ring 11. The second sealing ring 11 is beneficial to prevent the leakage of oil between the cylinder body 9 and the side wall of the piston 12, and to avoid the axial movement of the piston 12. The second sealing ring 11 can be an axial combined sealing ring made of high-temperature-resistant fluorine rubber material, or other high-temperature-resistant sealing materials, which are not limited herein.

[0043] Specifically, the pilot control valve 2 comprises a pilot oil inlet, a pilot oil outlet 6 and a pilot oil return port, the pilot oil outlet 6 is in communication with the pilot oil inlet and the pilot oil return port alternatively, the pilot oil inlet is connected with the oil pump unit 1, the pilot oil outlet 6 is connected with the oil inlet P 8 through the first oil path 7, and the pilot oil return port is connected with the oil tank 5. When the pilot control valve 2 is opened, the pilot oil inlet is in communication with the pilot oil outlet 6, so that the pressure oil is transmitted; when the pilot control valve 2 is closed, the pilot oil outlet 6 is in communication with the pilot oil return port, so that the pilot control valve 2 is filled with hydraulic oil, thereby automatically balancing with the ambient pressure and improving the adaptability to the ambient pressure.

[0044] Specifically, the hole diameter of the through hole is equal to the diameter of the pilot oil outlet 6, and the diameter of the first oil path 7 is also equal to the diameter of the pilot oil outlet 6, so that in the switching process of opening the pilot control valve 2, the pressure oil flowing through the through hole and the oil path does not generate additional liquid resistance, which is beneficial to the pressure oil maintaining the effective pressure to enter the main switching valve 4; the diameter of the oil return port T16 is greater than the diameter of the pilot oil outlet 6, which is beneficial to reducing the resistance of the pressure oil flowing out of the oil return port T16, and at the same time, in the reset process of the pilot control valve 2, when the pressure oil flows through the quick reset unit, the through hole plays a role of liquid resistance, so that the pressure oil in the main switching valve can generate sufficient back pressure, so that the piston 12 can overcome the resistance such as spring force and friction force and separate from the second end surface, thereby making as much pressure oil as possible flow out through the oil return port T16 with a larger diameter, which is beneficial to the quick reset of the main switching valve 4. The through hole can be designed as a straight through hole, a spiral hole or other shape through hole according to actual working needs, which is not limited here.

[0045] In some embodiments, the main switching valve 4 comprises a valve core and a valve sleeve, the valve sleeve is internally provided with a cavity, the valve core is slidably arranged in the cavity, and the valve core divides the cavity into a control cavity and a moving cavity, the main connection port A15 is connected with the control cavity through the second oil path 18; the moving cavity comprises a switching oil return port, the switching oil return port is connected with the oil tank 5, so that the main switching valve 4 is filled with hydraulic oil, and in the working process, the hydraulic pressure borne by the main switching valve 4 is the effective pressure for overcoming the load, which automatically balances the pressure of the environment, realizes the stable operation of the switching circuit in a wide pressure environment, and improves the adaptability to the ambient pressure.

[0046] As a further preferred embodiment, the linear expansion coefficients of the materials adopted by the spool and the valve sleeve are consistent, such as 17-4PH stainless steel and Monel K500 alloy, so that when the main reversing valve 4 is applied to different temperature working conditions between normal temperature and 200℃, the thermal deformation caused by temperature change to the valve sleeve and the spool is consistent, thereby facilitating the stable cooperation between the valve sleeve and the spool in different temperature environments, enabling the reversing circuit to operate stably in a wide temperature environment, and improving its adaptability to a wide temperature environment. The selection of specific materials needs to be based on the actual application scenario to preset the allowed difference threshold, so as to select the materials to ensure the performance of normal work in the actual temperature change range, which is not limited here.

[0047] The quick reset unit 3 provided in this embodiment makes the main reversing valve 4 not restricted by the small diameter of the pilot control valve 2 in the reset process, the linear expansion coefficients of the materials adopted by the spool and the valve sleeve are consistent, and the pilot oil return port, the reversing oil return port and the oil return port T are respectively connected with the oil tank to automatically balance the environmental pressure inside and outside the reversing circuit, which is suitable for deep earth fields where the environmental temperature and the environmental pressure change in a wide range, such as in the fields of drilling and logging. The pilot control reversing circuit with quick reset is in the process of deepening into the underground, and its environment rises from normal temperature and pressure on the ground to high temperature and high pressure underground. The environmental temperature change range in this field is between normal temperature and 200℃, and the environmental pressure change range is between 0 and 140MPa, or even higher.

[0048] The quick reset unit 3 provided in this embodiment makes the main reversing valve 4 not restricted by the small diameter of the pilot control valve 2 in the reset process, the main reversing valve 4 spool and the valve sleeve adopt high-temperature-resistant materials with equal or similar linear expansion coefficients, which are also suitable for deep space fields where the environmental temperature changes in a wide range and the environmental pressure is relatively stable, such as in space stations. The pilot control reversing circuit with quick reset may be in the station or outside the station. The station is in a normal pressure environment, and the outside of the station is in a high vacuum environment. When deepening into the space environment from the ground to a distance of about 400km, the surface temperature of the space station can reach about 150℃ or even higher under direct sunlight. Therefore, the environmental temperature change range of the pilot control reversing circuit with quick reset can reach above 150℃.

[0049] The pilot oil return port, the reversing oil return port and the oil return port T are respectively connected with the oil tank, which makes the environmental pressure inside and outside the reversing circuit automatically balanced, and is also suitable for deep sea fields where the environmental pressure changes in a wide range and the environmental temperature is relatively stable, such as seabed exploration. The pilot control reversing circuit with quick reset is in the process of working at the seabed, and the working pressure gradually deepens from the normal pressure environment at sea level to a high pressure environment of about 120MPa. The diving depth is about 11000m underwater. With the change of the depth of the sea water, the environmental pressure changes in the range of 0-120MPa, and the environmental temperature is between normal temperature and about 6℃.

[0050] It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading the above description. The scope of the application should therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with their full scope of equivalents. The disclosure of all articles and references referred to herein are incorporated by reference in their entirety.

Claims

1. A fast-reset pilot control reversing circuit, comprising an oil pump unit (1), a pilot control valve (2), and a main reversing valve (4) connected in sequence via an oil circuit, wherein the oil pump unit (1) is used to supply pressurized oil to the pilot control valve (2); characterized in that: The utility model also includes a quick reset unit (3) connected between the pilot control valve (2) and the main reversing valve (4); the quick reset unit (3) includes a cylinder body (9) and a piston (12) with a through hole in the center, the first end surface of the cylinder body (9) is provided with an oil inlet P (8) connected to the pilot control valve (2), and the second end surface is provided with a main connection port A (15) connected to the main reversing valve (4), the piston (12) is slidably connected to the inner wall of the cylinder body (9) between the first end surface and the second end surface of the cylinder body (9), and the side wall of the cylinder body (9) is provided with an oil return port T (16) near the second end surface, and the oil return port T (16) is connected to the oil tank (5); When the pilot control valve (2) is opened, the pressure oil flows into the cylinder body (9) through the oil inlet port P (8) and pushes the piston (12) to move to the second end face, so that the pressure oil flows into the main reversing valve (4) through the through hole and the main connection port A (15) to push the main reversing valve (4) to reverse; when the pilot control valve (2) is closed, the pressure oil in the main reversing valve (4) flows back to the cylinder body (9) and pushes the piston (12) to separate from the second end face, so that the return oil port T (16) is opened, and the pressure oil flows out through the return oil port T (16) to realize the reset of the main reversing valve (4).

2. The fast-reset pilot control reversing circuit according to claim 1, characterized in that: The rapid reset unit (3) further comprises an elastic structure (10), wherein the elastic structure (10) is provided between the first end surface and the piston (12), and the elastic structure (10) is in a compressed state.

3. The fast-reset pilot control reversing circuit according to claim 1, characterized in that: The end surface of the piston (12) facing the main connecting port A (15) is provided with a first groove, and a first sealing ring (13) is provided at the first groove. The thickness of the first sealing ring (13) is greater than the depth of the first groove, so that when the piston (12) moves to abut against the second end surface, a gap (14) is formed between the end surface of the piston (12) facing the main connecting port A (15) and the second end surface.

4. The fast-reset pilot control reversing circuit according to claim 2, characterized in that: When the pilot control valve (2) is closed, the thrust generated by the pressure oil in the main reversing valve (4) on the piston (12) is greater than the preload force of the elastic structure (10), so that the piston (12) can be pushed to separate from the second end face.

5. The fast-reset pilot control reversing circuit according to claim 4, characterized in that: The axial projection area of ​​the piston (12) is S, and the pressure of the pressure oil is p c , the oil pressure of the oil tank (5) is p t The piston (12) has a friction resistance F during the sliding process. t The oil in the cylinder (9) has an axial fluid force F during the flow process. h When the piston (12) is pressed against the second end surface, the pre-compression force F of the elastic structure (10) satisfies the following relationship: F<S×(p c -p t )-F f -F h 。 6. The fast-reset pilot control reversing circuit according to any one of claims 1 to 5, characterized in that: A second groove is provided on the side wall of the piston (12), a second sealing ring (11) is provided at the second groove, and the piston (12) and the cylinder body (9) are connected in a sliding and sealing manner via the second sealing ring (11).

7. The fast-reset pilot control reversing circuit according to any one of claims 1 to 5, characterized in that: The pilot control valve (2) includes a pilot oil inlet, a pilot oil outlet (6) and a pilot oil return port. The pilot oil outlet (6) is selectively connected to the pilot oil inlet and the pilot oil return port. The oil pump unit (1) is connected to the pilot oil inlet, the pilot oil outlet (6) is connected to the oil inlet P (8), and the pilot oil return port is connected to the oil tank (5).

8. The fast-reset pilot control reversing circuit according to claim 7, characterized in that: The diameter of the through hole is equal to the diameter of the pilot oil outlet (6), the diameter of the oil circuit is also equal to the diameter of the pilot oil outlet (6), and the diameter of the oil return port T (16) is larger than the diameter of the pilot oil outlet (6).

9. The fast-reset pilot control reversing circuit according to any one of claims 1 to 5, characterized in that: The main reversing valve (4) comprises a valve core and a valve sleeve. A cavity is provided inside the valve sleeve. The valve core is slidably arranged in the cavity. The valve core divides the cavity into two parts: a control cavity and a movable cavity. The main connecting port A (15) is connected to the control cavity via the oil circuit (18); the movable cavity comprises a reversing oil return port, and the reversing oil return port is connected to the oil tank (5).

10. The fast-reset pilot control reversing circuit according to claim 9, characterized in that: The linear expansion coefficients of the materials used for the valve core and the valve sleeve are consistent.

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