An ultra-high pressure and large flow relief valve with unloading mechanism

Abstract

This patent relates to the technical field of relief valves, specifically an ultra-high pressure and large flow relief valve with a unloading mechanism, including a main valve, a pilot valve and an electrically controlled unloading valve. The main valve includes a main valve body, a main valve seat, a main valve core, a sealing plug, a top plug, a spring seat and a main valve core spring. A low-pressure oil chamber is formed below the main valve seat, and a high-pressure oil chamber is formed between the lower part of the main valve core, the main valve body and the main valve seat. A pilot oil chamber is formed between the main valve core, the sealing plug, the spring seat and the main valve body. The pilot valve and the electrically controlled unloading valve are both connected to the pilot oil chamber. When the electrically controlled unloading valve is in effect, the pilot oil chamber is connected to the inside of the electrically controlled unloading valve through a one-way valve. At this time, the pressure difference between the pilot oil chamber and the high-pressure oil chamber reaches a maximum value, the main valve core opens to a maximum value, the system pressure is quickly unloaded, and the electrically controlled unloading valve can be remotely controlled to achieve remote unloading, thereby improving the safety of operation and solving the problem of manually operating the pilot valve to unload in scenarios where active unloading is required.

Description

Technical Field

[0001] The invention relates to the technical field of overflow valves, in particular to an ultra-high-pressure and large-flow overflow valve with a load-relief mechanism. Background Art

[0002] The overflow valve is used to adjust the working pressure and maximum pressure of the system. It is widely used in system equipment in the fields of engineering machinery, mining and metallurgy, ships and oceans. Existing overflow valves are divided into direct-acting and pilot-operated structures. For working conditions with rated pressure greater than 35Mpa and rated flow greater than 100L / min, the direct-acting overflow valve has problems such as small rated flow and poor dynamic and static characteristics, and the pilot-operated overflow valve has problems such as poor reliability and safety performance. Taking the marine high-pressure common rail system as an example, the rail cavity pressure is above 100Mpa and the flow is above 100L / min. Under ultra-high pressure and large flow conditions, if the valve core fails and bites, the system pressure will not be able to be unloaded. The continuous flow input of the oil supply pump will cause the system pressure to rise sharply, causing damage to other high-value components and equipment and safety accidents; for scenes that require active unloading, the pilot valve needs to be manually operated to unload, and there is a great safety risk in operating under ultra-high pressure environment. At the same time, due to the large spring stiffness of the pilot valve, there is a preload force in the installation space, which cannot completely unload the system. Summary of the invention

[0003] The present invention is intended to provide an ultra-high pressure and large flow relief valve with a unloading mechanism to solve the problem of manually operating a pilot valve to unload in scenarios requiring active unloading.

[0004] In order to achieve the above object, the basic scheme of the present invention is as follows: an ultra-high pressure and large flow relief valve with an unloading mechanism, comprising a main valve, a pilot valve and an electrically controlled unloading valve, wherein the pilot valve and the electrically controlled unloading valve are both installed on the main valve;

[0005] The main valve comprises a main valve body, a main valve seat, a main valve core, a sealing screw plug, a top screw plug, a spring seat and a main valve core spring. The main valve seat is fixed to the lower part of the main valve body. A low-pressure oil chamber is provided below the main valve seat. The main valve core is slidably connected in the main valve body, and the main valve core is located above the main valve seat. A high-pressure oil chamber is formed between the lower part of the main valve core, the main valve body and the main valve seat. An oil inlet is provided on the main valve body to communicate with the high-pressure oil chamber. An overflow channel is provided in the middle of the main valve seat to communicate with the high-pressure oil chamber and the low-pressure oil chamber. The bottom of the main valve core can be against the main valve seat and close the overflow channel, the spring seat is fixed on the upper part of the main valve body, the sealing plug is fixed in the middle of the main valve core, the main valve core spring is installed between the spring seat and the sealing plug, the top plug is fixed on the top of the main valve body, and a pilot oil chamber is formed between the main valve core, the sealing plug, the spring seat and the main valve body. A throttling hole is provided on the main valve core, and the throttling hole connects the pilot oil chamber and the high-pressure oil chamber, and the pilot valve and the electric control unloading valve are both connected to the pilot oil chamber.

[0006] Beneficial effects of the basic scheme: (1) System pressure oil enters the high-pressure oil chamber, passes through the throttle hole on the main valve core and enters the pilot oil chamber. The pilot oil chamber is connected to the pilot valve and the electric unloading valve. When the pilot valve and the electric unloading valve are closed, the pressure in the pilot oil chamber above the main valve core is equal to the pressure in the high-pressure oil chamber below. The main valve core is pressed against the main valve seat under the action of spring force and hydraulic pressure. As the system pressure increases, when it exceeds the opening pressure of the pilot valve, the pressure oil pushes open the pilot valve core and enters the oil in the pilot valve. At this time, due to the throttling effect of the throttling hole of the main valve core, the pressure of the pilot oil chamber on the upper part of the main valve core is lower than the pressure of the lower high-pressure oil chamber. As the system pressure continues to rise, the flow through the throttling hole of the main valve core continues to increase, the pressure difference generated continues to increase, and the clamping force above the main valve core decreases successively. When the clamping force becomes a negative value, the main valve core is lifted, the high-pressure oil chamber is connected with the low-pressure oil chamber, the relief valve begins to overflow, and finally the pressure of the high-pressure oil chamber of the relief valve is maintained at a certain set value p.

[0007] (2) This solution is provided with an electric-controlled unloading valve connected in parallel with the pilot valve. When the electric-controlled unloading valve is activated, the pilot oil chamber is connected to the inside of the electric-controlled unloading valve through the one-way valve. At this time, the pressure difference between the upper pilot oil chamber of the main valve core and the lower high-pressure oil chamber reaches the maximum value, the main valve core opens to the maximum value, the system pressure is quickly unloaded, and the electric-controlled unloading valve can be remotely controlled to achieve remote unloading, thereby improving the safety of operation.

[0008] Furthermore, the pilot valve includes a pilot valve seat, a pilot valve core, a pilot valve body, a pilot valve spring, a pilot valve regulating rod and a locking nut. A pilot valve mounting hole is provided on the side of the main valve body. The pilot valve seat and the pilot valve body are fixed in the pilot valve mounting hole. One end of the pilot valve seat is connected to the pilot oil chamber, and the other end of the pilot valve seat is against the pilot valve core. The pilot valve regulating rod is slidably connected to the end of the pilot valve body, and one end of the pilot valve regulating rod extends out of the pilot valve body. The pilot valve spring is installed between the pilot valve regulating rod and the pilot valve core, and the locking nut is threadedly connected to the end of the pilot valve regulating rod extending out of the pilot valve body. The pilot valve spring preload can be adjusted by the pilot valve regulating rod, thereby adjusting the opening pressure of the pilot valve, so that the pressure of the high-pressure oil chamber of the final overflow valve is maintained at a certain set value.

[0009] Further, the electrically controlled unloading valve comprises a one-way valve, an electrically controlled unloading valve base, a driving member, a ejector pin, a return spring, an unloading valve spring seat and an unloading valve sleeve. A unloading valve mounting hole is provided on the side of the main valve body. The one-way valve is installed in the unloading valve mounting hole. The electrically controlled unloading valve base is installed at the end of the unloading valve mounting hole. The unloading valve sleeve is installed in the electrically controlled unloading valve base. The ejector pin is slidably connected in the unloading valve sleeve. The unloading valve spring seat is installed in the unloading valve sleeve. The return spring sleeve is arranged in the middle of the ejector pin and abuts against the unloading valve spring seat. One end of the ejector pin abuts against the one-way valve for opening the one-way valve. The other end of the ejector pin abuts against the driving member. The driving member drives the ejector pin to slide along the unloading valve sleeve. By controlling the opening and closing of the one-way valve, the connection state between the internal space of the electric-controlled unloading valve and the pilot oil chamber is controlled. Under normal pressure or when complete unloading is required, the ejector needle opens the one-way valve, so that the internal space of the base of the electric-controlled unloading valve is connected to the pilot oil chamber, so that the pressure in the pilot oil chamber is reduced, thereby making the pressure in the high-pressure oil chamber greater than the pressure in the pilot oil chamber, so that the main valve core is lifted or fully lifted.

[0010] Furthermore, the driving member includes a proportional electromagnet and a lever, the lever is located at the end of the push rod, the lever is hinged on the base of the electric control unloading valve, one end of the lever is against the push rod, and the other end of the lever is against the proportional electromagnet, and the proportional electromagnet drives the lever to rotate. The electromagnetic force of the proportional electromagnet can be amplified by the lever and applied to the push rod. The higher the pressure of the ultra-high pressure relief valve, the greater the force of the electromagnet is required. The suction force of the existing proportional electromagnet products on the market is limited. The lever can reduce the demand for the proportional electromagnet, and the one-way valve can be opened by the electromagnetic force, so that the relief valve enters the unloading condition.

[0011] Furthermore, the one-way valve includes a one-way valve sleeve, a one-way valve spring seat, a one-way valve spring, a steel ball and a one-way valve oil-passing gasket. The one-way valve sleeve is fixed in the mounting hole of the unloading valve, the one-way valve oil-passing gasket is installed at the end of the one-way valve sleeve, the one-way valve spring seat is installed on the side of the one-way valve oil-passing gasket, one end of the one-way valve spring is installed on the one-way valve spring seat, the steel ball is fixed at the other end of the one-way valve spring, the steel ball can close the one-way valve sleeve, and the end of the ejector pin is against the steel ball.

[0012] Furthermore, it also includes a plurality of sealing rings, which are respectively installed at positions where the sealing needs to be strengthened in the main valve, the pilot valve and the electric control unloading valve, so as to increase the overall sealing effect.

[0013] Furthermore, an abnormal overflow channel is provided at the bottom of the main valve core, and the abnormal overflow channel is connected to the low-pressure oil chamber. A isobaric oil chamber connected to the high-pressure oil chamber is provided above the abnormal overflow channel. A rupture wall is provided between the isobaric oil chamber and the abnormal overflow channel, and the maximum bearing pressure of the rupture wall is F. When the main valve core is lifted normally, the pressure of the high-pressure oil chamber does not exceed F. When the main valve core is stuck and cannot be lifted normally, and the pressure of the high-pressure oil chamber and the isobaric oil chamber exceeds F, the rupture wall ruptures to connect the isobaric oil chamber with the abnormal overflow channel. When the main valve core is stuck abnormally and cannot be lifted normally for overflow, the pressure in the high-pressure oil chamber will rise sharply. When the pressure exceeds the maximum bearing pressure of the rupture wall, the rupture wall ruptures, and the system pressure is unloaded from the damaged part, so that the pressure stops rising, thereby avoiding the damage of the system chain, and achieving the purpose of protecting the system and other high-value equipment.

[0014] Furthermore, the contact surface between the main valve core and the main valve body is provided with a DLC coating. The DLC coating can increase the surface hardness and smoothness of the contact surface between the main valve core and the main valve body, reduce the risk of the main valve core being stuck, and improve reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A top view of an embodiment of the present invention;

[0016] Figure 2 for Figure 1 Sectional view of AA in the middle;

[0017] Figure 3 for Figure 2 A magnified schematic diagram of B;

[0018] Figure 4 for Figure 2 A magnified schematic diagram of C in the middle. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The figure marks in the drawings of the specification include: main valve 1, pilot valve 2, electric control unloading valve 3, main valve body 4, main valve seat 5, main valve core 6, sealing plug 7, top plug 8, spring seat 9, main valve core spring 10, low-pressure oil chamber 11, high-pressure oil chamber 12, overflow channel 13, pilot oil chamber 14, throttle hole 15, abnormal overflow channel 16, same-pressure oil chamber 17, rupture wall 18, pilot valve seat 19, pilot valve core 20, pilot valve body 21, pilot valve spring 22, pilot valve adjusting rod 23, locking nut 24, electric control unloading valve base 25, ejector pin 26, return spring 27, unloading valve spring seat 28, unloading valve sleeve 29, proportional solenoid 30, lever 31, one-way valve sleeve 32, one-way valve spring seat 33, one-way valve spring 34, steel ball 35, one-way valve oil-passing gasket 36, and sealing ring 37.

[0021] Example

[0022] Basically as attached Figure 1 , Figure 2 As shown: an ultra-high pressure and large flow relief valve with an unloading mechanism, comprising a main valve 1, a pilot valve 2 and an electric control unloading valve 3, wherein the pilot valve 2 and the electric control unloading valve 3 are both installed on the main valve 1;

[0023] The main valve 1 includes a main valve body 4, a main valve seat 5, a main valve core 6, a sealing screw plug 7, a top screw plug 8, a spring seat 9 and a main valve core spring 10. The main valve seat 5 is fixed to the lower part of the main valve body 4. Below the main valve seat 5 is a low-pressure oil chamber 11. The main valve core 6 is slidably connected in the main valve body 4. The contact surface between the main valve core 6 and the main valve body 4 is provided with a DLC coating, and the main valve core 6 is located above the main valve seat 5. A high-pressure oil chamber 12 is formed between the lower part of the main valve core 6, the main valve body 4 and the main valve seat 5. The main valve body 4 is provided with an oil inlet and a high-pressure The oil chamber 12 is connected, and an overflow channel 13 is provided in the middle of the main valve seat 5 to connect the high-pressure oil chamber 12 with the low-pressure oil chamber 11. The bottom of the main valve core 6 can abut against the main valve seat 5 and close the overflow channel 13. The spring seat 9 is fixed on the upper part of the main valve body 4, and the sealing plug 7 is fixed in the middle of the main valve core 6. The main valve core spring 10 is installed between the spring seat 9 and the sealing plug 7. The top plug 8 is fixed on the top of the main valve body 4. A pilot oil chamber 14 is formed between the main valve core 6, the sealing plug 7, the spring seat 9 and the main valve body 4. Figure 3As shown, a throttle hole 15 is provided on the main valve core 6, and the throttle hole 15 is connected to the pilot oil chamber 14 and the high-pressure oil chamber 12, and the pilot valve 2 and the electric control unloading valve 3 are both connected to the pilot oil chamber 14. An abnormal overflow channel 16 is provided at the bottom of the main valve core 6, and the abnormal overflow channel 16 is connected to the low-pressure oil chamber 11. A pressure-same oil chamber 17 connected to the high-pressure oil chamber 12 is provided above the abnormal overflow channel 16. A rupture wall 18 is provided between the pressure-same oil chamber 17 and the abnormal overflow channel 16. The maximum pressure of the rupture wall 18 is F. When the main valve core 6 is lifted normally, the pressure of the high-pressure oil chamber 12 does not exceed F. When the main valve core 6 is stuck and cannot be lifted normally, and the pressures of the high-pressure oil chamber 12 and the pressure-same oil chamber 17 exceed F, the rupture wall 18 ruptures so that the pressure-same oil chamber 17 is connected to the abnormal overflow channel 16.

[0024] The pilot valve 2 includes a pilot valve seat 19, a pilot valve core 20, a pilot valve body 21, a pilot valve spring 22, a pilot valve adjusting rod 23 and a locking nut 24. A pilot valve 2 mounting hole is provided on the side of the main valve body 4. The pilot valve seat 19 and the pilot valve body 21 are fixed in the pilot valve 2 mounting hole. One end of the pilot valve seat 19 is connected to the pilot oil chamber 14, and the other end of the pilot valve seat 19 is against the pilot valve core 20. The pilot valve adjusting rod 23 is slidably connected to the end of the pilot valve body 21, and one end of the pilot valve adjusting rod 23 extends out of the pilot valve body 21. The pilot valve spring 22 is installed between the pilot valve adjusting rod 23 and the pilot valve core 20. The locking nut 24 is threadedly connected to the end of the pilot valve adjusting rod 23 extending out of the pilot valve body 21.

[0025] Combination Figure 4 As shown, the electric control unloading valve 3 includes a one-way valve, an electric control unloading valve base 25, a driving member, a pin 26, a return spring 27, an unloading valve spring seat 28 and an unloading valve sleeve 29. A unloading valve mounting hole is provided on the side of the main valve body 4. The one-way valve is mounted in the unloading valve mounting hole. The electric control unloading valve base 25 is mounted at the end of the unloading valve mounting hole. The unloading valve sleeve 29 is mounted in the electric control unloading valve base 25. The pin 26 is slidably connected in the unloading valve sleeve 29. The unloading valve spring seat 28 is mounted in the unloading valve sleeve 29. The return spring 27 is sleeved on the middle part of the ejector pin 26 and abuts against the unloading valve spring seat 28. One end of the ejector pin 26 abuts against the one-way valve for opening the one-way valve. The driving member includes a proportional solenoid 30 and a lever 31. The lever 31 is located at the end of the ejector rod. The lever 31 is hinged on the electric-controlled unloading valve base 25. One end of the lever 31 abuts against the ejector rod, and the other end of the lever 31 abuts against the proportional solenoid 30. The proportional solenoid 30 drives the lever 31 to rotate, and the lever 31 drives the ejector pin 26 to slide along the unloading valve sleeve 29.

[0026] The one-way valve includes a one-way valve sleeve 32, a one-way valve spring seat 33, a one-way valve spring 34, a steel ball 35 and a one-way valve oil-passing gasket 36. The one-way valve sleeve 32 is fixed in the mounting hole of the unloading valve, the one-way valve oil-passing gasket 36 is installed at the end of the one-way valve sleeve 32, the one-way valve spring seat 33 is installed on the side of the one-way valve oil-passing gasket 36, one end of the one-way valve spring 34 is installed on the one-way valve spring seat 33, and the steel ball 35 is fixed on the other end of the one-way valve spring 34. The steel ball 35 can close the one-way valve sleeve 32, and the end of the ejector pin 26 is against the steel ball 35.

[0027] It also includes a plurality of sealing rings 37 , which are respectively installed between the top screw plug 8 and the main valve body 4 , between the unloading valve spring seat 28 and the electric-controlled unloading valve base 25 , and between the electric-controlled unloading valve base 25 and the main valve body 4 .

[0028] The specific implementation process is as follows: the system pressure oil enters the high-pressure oil chamber 12, passes through the throttle hole 15 on the main valve core 6 and enters the pilot oil chamber 14. The pilot oil chamber 14 is connected to the pilot valve 2 and the electric control unloading valve 3. The pilot pressure oil acts on the left end of the pilot valve core 20 and the right end of the steel ball 35 of the electric control unloading valve 3. When the pilot valve 2 and the electric control unloading valve 3 are closed, the pressure of the upper pilot oil chamber 14 of the main valve core 6 is equal to that of the lower high-pressure oil chamber 12. The main valve core 6 is pressed against the main valve seat 5 under the action of the spring force and the hydraulic pressure. At this time, the main valve core 6 pressure F borne by the main valve seat 5 is:

[0029] F = Fs + pA' - pA;

[0030] Where:

[0031] Fs is the main valve core 6 spring preload force,

[0032] A' is the effective area of ​​the pilot oil chamber 14,

[0033] A is the effective area of ​​the high pressure oil chamber 12,

[0034] p is the pressure of the high-pressure oil chamber 12;

[0035] Because the effective area A' of the upper cavity of the main valve core 6 is larger than the effective area F of the lower cavity of the main valve core 6, F is positive at this time, the main valve core 6 is pressed against the main valve seat 5 and is in a sealed state. As the system pressure increases, when it exceeds the opening pressure of the pilot valve 2, the pressure oil pushes open the pilot valve core 20 and enters the oil cavity in the pilot valve 2. At this time, due to the throttling effect of the throttle hole 15 of the main valve core 6, the pressure P' of the upper pilot oil cavity 14 of the main valve core 6 is less than the pressure p of the lower high-pressure oil cavity 12. At this time, the main valve seat 5 is pressed by the main valve core 6 with the pressure F being:

[0036] F = Fs + p'A' - pA;

[0037] Where:

[0038] p' is the pressure of the pilot oil chamber 14;

[0039] As the system pressure continues to rise, the flow through the throttle hole 15 of the main valve core 6 continues to increase, the generated pressure difference continues to increase, and the clamping force F decreases successively. When F becomes a negative value, the main valve core 6 is lifted, the high-pressure oil chamber 12 is connected to the low-pressure oil chamber 11, and the relief valve begins to overflow. Finally, the pressure in the high-pressure oil chamber 12 of the relief valve is maintained at a certain set value.

[0040] The electrically controlled unloading valve 3 is connected in parallel with the pilot valve 2. When the electrically controlled unloading valve 3 is in effect, the pilot oil chamber 14 is connected to the inside of the electrically controlled unloading valve 3 through the oil hole of the one-way valve sleeve 32. At this time, the pressure difference between the upper pilot oil chamber 14 and the lower high-pressure oil chamber 12 of the main valve core 6 reaches the maximum value. The main valve core 6 opens to the maximum value, and the system pressure is quickly unloaded. At the same time, the influence of the preload force of the pilot valve spring 22 is avoided. The system can achieve sufficient remote unloading, thereby improving the safety of operation.

[0041] When the main valve core 6 is abnormally stuck, if the system pressure cannot be unloaded in time, the pressure in the high-pressure oil chamber 12 will increase abnormally and sharply. When the pressure exceeds the maximum bearing pressure of the rupture wall 18, the rupture wall 18 will rupture, so that the high-pressure oil chamber 12 is directly connected with the low-pressure oil chamber 11, thereby avoiding damage to other high-value components and equipment and safety accidents.

[0042] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0043] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An ultra-high pressure and large flow relief valve with a unloading mechanism, characterized in that: It includes a main valve, a pilot valve and an electric-controlled unloading valve, wherein the pilot valve and the electric-controlled unloading valve are both installed on the main valve; The main valve comprises a main valve body, a main valve seat, a main valve core, a sealing screw plug, a top screw plug, a spring seat and a main valve core spring. The main valve seat is fixed to the lower part of the main valve body. A low-pressure oil chamber is provided below the main valve seat. The main valve core is slidably connected in the main valve body, and the main valve core is located above the main valve seat. A high-pressure oil chamber is formed between the lower part of the main valve core, the main valve body and the main valve seat. An oil inlet is provided on the main valve body to communicate with the high-pressure oil chamber. An overflow channel is provided in the middle of the main valve seat to communicate with the high-pressure oil chamber and the low-pressure oil chamber. The bottom of the main valve core can be against the main valve seat and close the overflow channel, the spring seat is fixed on the upper part of the main valve body, the sealing plug is fixed in the middle of the main valve core, the main valve core spring is installed between the spring seat and the sealing plug, the top plug is fixed on the top of the main valve body, and a pilot oil chamber is formed between the main valve core, the sealing plug, the spring seat and the main valve body. A throttling hole is provided on the main valve core, and the throttling hole connects the pilot oil chamber and the high-pressure oil chamber, and the pilot valve and the electric control unloading valve are both connected to the pilot oil chamber.

2. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 1, characterized in that: The pilot valve includes a pilot valve seat, a pilot valve core, a pilot valve body, a pilot valve spring, a pilot valve adjusting rod and a locking nut. A pilot valve mounting hole is provided on the side of the main valve body. The pilot valve seat and the pilot valve body are fixed in the pilot valve mounting hole. One end of the pilot valve seat is connected to the pilot oil chamber, and the other end of the pilot valve seat is against the pilot valve core. The pilot valve adjusting rod is slidably connected to the end of the pilot valve body, and one end of the pilot valve adjusting rod extends out of the pilot valve body. The pilot valve spring is installed between the pilot valve adjusting rod and the pilot valve core, and the locking nut is threadedly connected to the end of the pilot valve adjusting rod extending out of the pilot valve body.

3. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 1, characterized in that: The electrically controlled unloading valve comprises a one-way valve, an electrically controlled unloading valve base, a driving member, a ejector pin, a return spring, an unloading valve spring seat and an unloading valve sleeve. A unloading valve mounting hole is provided on the side of the main valve body. The one-way valve is mounted in the unloading valve mounting hole. The electrically controlled unloading valve base is mounted at the end of the unloading valve mounting hole. The unloading valve sleeve is mounted in the electrically controlled unloading valve base. The ejector pin is slidably connected in the unloading valve sleeve. The unloading valve spring seat is mounted in the unloading valve sleeve. The return spring sleeve is arranged in the middle of the ejector pin and abuts against the unloading valve spring seat. One end of the ejector pin abuts against the one-way valve for opening the one-way valve. The other end of the ejector pin abuts against the driving member. The driving member drives the ejector pin to slide along the unloading valve sleeve.

4. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 3, characterized in that: The driving member includes a proportional electromagnet and a lever, wherein the lever is located at the end of the push rod and is hinged on the base of the electric-controlled unloading valve. One end of the lever abuts against the push rod, and the other end of the lever abuts against the proportional electromagnet, and the proportional electromagnet drives the lever to rotate.

5. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 4, characterized in that: The one-way valve comprises a one-way valve sleeve, a one-way valve spring seat, a one-way valve spring, a steel ball and a one-way valve oil-passing gasket. The one-way valve sleeve is fixed in the mounting hole of the unloading valve, the one-way valve oil-passing gasket is installed at the end of the one-way valve sleeve, the one-way valve spring seat is installed on the side of the one-way valve oil-passing gasket, one end of the one-way valve spring is installed on the one-way valve spring seat, the steel ball is fixed at the other end of the one-way valve spring, the steel ball can close the one-way valve sleeve, and the end of the ejector pin abuts against the steel ball.

6. An ultra-high pressure and large flow relief valve with a unloading mechanism according to any one of claims 1 to 5, characterized in that: It also includes a plurality of sealing rings, which are respectively installed at positions where enhanced sealing is required in the main valve, the pilot valve and the electric control unloading valve.

7. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 1, characterized in that: An abnormal overflow channel is provided at the bottom of the main valve core, and the abnormal overflow channel is connected with the low-pressure oil chamber. A iso-pressure oil chamber connected with the high-pressure oil chamber is provided above the abnormal overflow channel. A rupture wall is provided between the iso-pressure oil chamber and the abnormal overflow channel, and the maximum bearing pressure of the rupture wall is F. When the main valve core is lifted normally, the pressure in the high-pressure oil chamber does not exceed F. When the main valve core is stuck and cannot be lifted normally, and the pressures of the high-pressure oil chamber and the iso-pressure oil chamber exceed F, the rupture wall ruptures to connect the iso-pressure oil chamber with the abnormal overflow channel.

8. The ultra-high pressure and large flow relief valve with a unloading mechanism according to claim 7, characterized in that: The contact surface between the main valve core and the main valve body is provided with a DLC coating.

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