Normally-closed high-pressure large-flow directional control valve structure

Abstract

The invention discloses a normally-closed high-pressure large-flow directional control valve structure. The control valve is of a split type structure and comprises a control valve body, a pilot hydraulic adjusting mechanism, a pilot valve and a cooperative control mechanism. The pilot valve receives an external signal and then conveys pilot pressure oil to the pilot hydraulic adjusting mechanism to excite the pilot hydraulic adjusting mechanism to make a response, and the response and the cooperation of the cooperative control mechanism jointly act on the control valve body to drive the valve element to move accurately, so that opening and closing adjustment of the high-pressure large-flow direction control valve is completed. The high-pressure high-flow direction control valve is controlled to be opened and closed by low-pressure pilot pressure oil, and the high-pressure high-flow direction control valve is suitable for typical working conditions of 70 MPa high pressure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic technology, and in particular relates to a normally closed high-pressure large-flow directional control valve structure. BACKGROUND

[0002] The high-pressure large-flow directional control valve is a core control element of a large-flow hydraulic system, and determines the control performance of equipment. A traditional directional control valve controls the oil pressure in the upper cavity of a valve core to control the movement of the valve core, realize the opening and closing functions of the valve core, and achieve the purpose of directional control. In order to ensure that the directional control valve does not leak in the closed state, the pressure in the upper cavity of the valve core needs to be consistent with the pressure level of the main oil passage of the valve body. However, due to the limitation of the control circuit hydraulic level, the traditional directional control valve cannot meet the requirements of 70MPa high-pressure large-flow directional control.

[0003] Nowadays, the hydraulic system pressure level of large-scale die forging presses, linear friction welding and other "industrial mother machines" has reached 70MPa. The existing directional control valve cannot meet the hydraulic system pressure level of large-scale die forging presses, linear friction welding and other equipment. SUMMARY

[0004] In view of the above defects or improvement needs of the prior art, the present application provides a normally closed high-pressure large-flow directional control valve structure to at least solve the problem that the existing directional control valve cannot meet the hydraulic system pressure level of large-scale die forging presses, linear friction welding and other equipment.

[0005] In order to achieve the above-mentioned purpose, the present application provides a normally closed high-pressure large-flow directional control valve structure, which comprises: a control valve main body, the control valve main body comprising a valve body and a valve core assembly, the valve body having an oil inlet cavity and an oil return cavity, the valve body being connected with a hydraulic system through the oil inlet cavity and the oil return cavity, the valve core assembly being movably arranged in the valve body to control the opening and closing degree of the oil inlet cavity and the oil return cavity and thereby control the direction, flow and pressure of the hydraulic system; a pilot hydraulic adjusting mechanism arranged at the upper end of the control valve main body, the pilot hydraulic adjusting mechanism being connected with the valve core assembly and acting on the valve core assembly to make the valve core assembly move; a pilot valve connected with the pilot hydraulic adjusting mechanism, the pilot valve being used for receiving an external control signal and inputting a pilot pressure oil to the pilot hydraulic adjusting mechanism to control the working of the pilot hydraulic adjusting mechanism; a cooperative control mechanism, the cooperative control mechanism having an elastic control assembly, the elastic control assembly being connected with the pilot hydraulic adjusting mechanism to apply an action to the valve core assembly through the pilot hydraulic adjusting mechanism to cooperate with the pilot hydraulic adjusting mechanism acting on the valve core assembly.

[0006] Further, a main valve cavity extending along an axis of the valve body is formed in the valve body, the oil inlet cavity is formed in the horizontal direction of the valve body and communicates with the main valve cavity, and the oil return cavity is formed in the vertical direction of the valve body and communicates with the main valve cavity, the oil inlet cavity and the oil return cavity being perpendicular to each other; wherein the valve core assembly is arranged in the main valve cavity and located between the oil inlet cavity and the oil return cavity.

[0007] Furthermore, the valve core assembly includes a valve core and a valve sleeve; the valve sleeve is fixedly installed inside the main valve cavity, and the valve core is slidably arranged inside the valve sleeve; wherein the pilot hydraulic adjustment mechanism is connected to the valve core to act on the valve core.

[0008] Furthermore, the lower port of the valve sleeve is opposite to the oil return chamber, and the valve sleeve is radially provided with an oil inlet hole opposite to the oil inlet chamber; the valve core moves between the lower port of the valve sleeve and the oil inlet hole to control the opening and closing degree of the oil inlet chamber and the oil return chamber.

[0009] Furthermore, a first valve sleeve seal is provided between the valve sleeve and the main valve chamber; a valve core is provided with a valve core sealing ring, which divides the inner hole of the valve sleeve into a valve core lower chamber and a valve core upper chamber, the valve core lower chamber is connected to the oil inlet chamber, and a valve core center hole and a valve core pressure reducing hole are opened on the valve core; a valve core buffer structure is provided at the bottom of the valve core.

[0010] Furthermore, the pilot hydraulic adjustment mechanism includes: a pilot cover plate, which is fixedly mounted on the valve body; a pilot valve stem, which is slidably mounted in the pilot cover plate along the central axis direction of the pilot cover plate, wherein a pilot valve stem seal is provided between the pilot cover plate and the pilot valve stem, and the pilot valve stem seal divides the inner hole of the pilot cover plate into a pilot valve stem lower chamber and a pilot valve stem upper chamber. When the pilot valve stem lower chamber is connected to the pilot pressure oil, an upward pressure is generated on the pilot valve stem, and when the pilot valve stem upper chamber is connected to the pilot pressure oil, a downward pressure is generated on the pilot valve stem, which dynamically drives the axial movement of the pilot valve stem, and the pilot valve stem limits the axial displacement of the valve core by moving up and down.

[0011] Furthermore, the pilot hydraulic adjustment mechanism also includes: a guide cover, which is installed in the main valve cavity and extends to the lower end of the pilot cover plate; a guide hole is opened in the guide cover, and the pilot valve stem passes through the guide hole and is connected to the valve core assembly; wherein, a first guide cover seal is provided between the guide cover and the main valve cavity, a second guide cover seal is provided between the guide cover and the pilot cover plate, and a second valve sleeve seal is provided between the guide cover and the valve sleeve.

[0012] Furthermore, the pilot hydraulic regulating mechanism further includes: a pilot connecting plate, the pilot connecting plate is mounted on the pilot cover plate, and the pilot valve is fixedly mounted on the pilot cover plate through the pilot connecting plate.

[0013] Furthermore, the elastic control component includes: a spring pressure cover, which is fixedly mounted on the pilot cover plate, and a spring pressure cover seal is installed between the spring pressure cover and the pilot cover plate; a spring, which is installed inside the upper cavity of the pilot valve stem; and a spring washer, which is installed inside the upper cavity of the pilot valve stem; wherein the spring cooperates with the pilot pressure oil to control the axial movement of the pilot valve stem.

[0014] Furthermore, the collaborative control mechanism also includes: an adjusting rod, which is threadedly installed on the spring pressure cover, and an adjusting rod seal is provided between the adjusting rod and the spring pressure cover; a lock nut, which is installed on the adjusting rod; the adjusting rod controls the opening degree of the valve port of the high-pressure and large-flow directional control valve by adjusting the maximum stroke S2 ​​of the pilot valve stem through the limit of the lock nut.

[0015] According to the normally closed high-pressure and large-flow directional control valve structure provided by the present invention, it includes a control valve body, a pilot hydraulic adjustment mechanism, a pilot valve and a cooperative control mechanism; the control valve body includes a valve body and a valve core assembly, the valve body has an oil inlet chamber and an oil return chamber, the valve body is connected to the hydraulic system through the oil inlet chamber and the oil return chamber, and the valve core assembly is movably arranged in the valve body to control the opening and closing degree of the oil inlet chamber and the oil return chamber and thus control the direction, flow and pressure of the hydraulic system; the pilot hydraulic adjustment mechanism is arranged at the upper end of the control valve body, the pilot hydraulic adjustment mechanism is connected to the valve core assembly and acts on the valve core assembly to make the valve core assembly move; the pilot valve is connected to the pilot hydraulic adjustment mechanism, the pilot valve is used to receive an external control signal and input pilot pressure oil to the pilot hydraulic adjustment mechanism to control the operation of the pilot hydraulic adjustment mechanism; the cooperative control mechanism has an elastic control assembly, the elastic control assembly is connected to the pilot hydraulic adjustment mechanism to apply action to the valve core assembly through the pilot hydraulic adjustment mechanism to cooperate with the pilot hydraulic adjustment mechanism to act on the valve core assembly. This allows low-pressure pilot oil to control the opening and closing of high-pressure, high-flow directional control valves, eliminating the need for the pressure in the valve core chamber to match the pressure level of the valve body's main oil circuit. This solves the problem of existing directional control valves being unable to meet the pressure levels of hydraulic systems in large die forging presses, linear friction welding equipment, and other equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a structural diagram of the normally closed high-pressure, high-flow directional control valve involved in the present invention (the maximum opening is adjusted to 100% closed); Figure 2 This is a structural diagram of the normally closed high-pressure, high-flow directional control valve involved in the present invention (the maximum opening is adjusted to 100% open); Figure 3 This is a structural diagram of the normally closed high-pressure, high-flow directional control valve involved in the present invention (the maximum opening is adjusted to a 50% closed state); Figure 4 This is a diagram of the valve core state of a normally closed high-pressure, high-flow directional control valve. (a) is the open state; (b) is the closed state; and (c) is the opening / closing state.

[0017] Figure 5 This is the control principle diagram of the normally closed high-pressure and large-flow directional control valve.

[0018] Explanation of reference numerals: T1, control valve body; T2, pilot hydraulic adjustment mechanism; T3, cooperative control mechanism.

[0019] J1, main valve chamber; J2, valve core assembly; J3, elastic control assembly.

[0020] 1. Valve body; 2. First valve sleeve seal; 3. Valve sleeve; 4. Valve core; 5. Second valve sleeve seal; 6. First guide cover seal; 7. Guide cover; 8. Second guide cover seal; 9. Pilot valve stem; 10. Pilot cover plate; 11. Pilot valve stem seal; 12. Spring pressure cover seal; 13. Spring pressure cover; 14. Spring; 15. Spring washer; 16. Adjusting rod seal; 17. Adjusting rod; 18. Lock nut; 19. Pilot connecting plate; 20. Pilot valve.

[0021] 101. Oil inlet chamber; 102. Oil return chamber; 103. Oil inlet hole; 401. Center hole; 402. Valve core buffer structure; 403. Valve core pressure reducing hole; 404. Valve core lower chamber; 405. Valve core sealing ring; 406. Valve core upper chamber; 901. Pilot valve stem sealing ring; 1001. Pilot valve stem lower chamber; 1002. Pilot valve stem upper chamber. DETAILED DESCRIPTION

[0022] 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.

[0023] See also Figure 1 and Figure 2This embodiment provides a normally closed high-pressure, high-flow directional control valve structure, including a control valve body T1, a pilot hydraulic adjustment mechanism T2, a pilot valve 20, and a coordinated control mechanism T3. The control valve body T1 includes a valve body 1 and a valve core assembly J2. The valve body 1 has an oil inlet chamber 101 and an oil return chamber 102. The valve body 1 is connected to the hydraulic system through the oil inlet chamber 101 and the oil return chamber 102. The valve core assembly J2 is movably arranged in the valve body 1 to control the opening and closing degree of the oil inlet chamber 101 and the oil return chamber 102, thereby controlling the direction, flow, and pressure of the hydraulic system. The pilot hydraulic adjustment mechanism T2 is arranged in the control valve body T1. At the upper end of the pilot hydraulic regulating mechanism T2, the pilot hydraulic regulating mechanism T2 is connected to the valve core assembly J2 and acts on the valve core assembly J2 to make the valve core assembly J2 move; the pilot valve 20 is connected to the pilot hydraulic regulating mechanism T2, and the pilot valve 20 is used to receive an external control signal and input pilot pressure oil to the pilot hydraulic regulating mechanism T2 to control the operation of the pilot hydraulic regulating mechanism T2; the cooperative control mechanism T3 has an elastic control component J3, and the elastic control component J3 is connected to the pilot hydraulic regulating mechanism T2 to apply action to the valve core assembly J2 through the pilot hydraulic regulating mechanism T2 to cooperate with the pilot hydraulic regulating mechanism T2 to act on the valve core assembly J2.

[0024] Specifically, the control valve body T1 is connected to the hydraulic system and directly determines the flow direction of high-pressure oil by changing the on-off state of the oil circuit. The valve body 1, as the core pressure-bearing component, cooperates with the valve core assembly J2 through internal precision flow channels to precisely control the delivery of high-pressure oil. The oil inlet chamber 101 is used to receive high-pressure oil from the hydraulic system, while the oil return chamber 102 supplies low-pressure oil to the hydraulic system. The pressure difference between the two drives the movement of the valve core assembly J2.

[0025] The lower end of the pilot hydraulic adjustment mechanism T2 is connected to the control valve body T1, and the upper end is embedded with a cooperative control mechanism T3. A pilot valve 20 is installed on one side. The pilot valve 20 receives an external signal and then transmits the pilot pressure oil to the pilot hydraulic adjustment mechanism T2 to stimulate the pilot hydraulic adjustment mechanism T2 to respond. This response plus the cooperation of the cooperative control mechanism T3 act together on the control valve body T1 to drive the precise displacement of the valve core 4 and thus complete the opening and closing adjustment of the high-pressure and large-flow directional control valve.

[0026] In one possible embodiment, a main valve chamber J1 extending along its central axis is opened in the valve body 1, an oil inlet chamber 101 is opened along the horizontal direction of the valve body 1 and communicates with the main valve chamber J1, an oil return chamber 102 is opened along the vertical direction of the valve body 1 and communicates with the main valve chamber J1, and the oil inlet chamber 101 and the oil return chamber 102 are perpendicular to each other; wherein, the valve core assembly J2 is arranged in the main valve chamber J1 and is located between the oil inlet chamber 101 and the oil return chamber 102.

[0027] Specifically, the main valve chamber J1 is cylindrical and is the portion of the valve body 1 where the oil flow channel is arranged. It limits the maximum migration range of the oil and provides sufficient space for the movement of the valve core assembly J2.

[0028] In one possible implementation, the valve core assembly J2 includes a valve core 4 and a valve sleeve 3; The valve sleeve 3 is fixedly mounted inside the main valve chamber J1 , and the valve core 4 is slidably disposed inside the valve sleeve 3 ; wherein the pilot hydraulic pressure regulating mechanism T2 is connected to the valve core 4 to act on the valve core 4 .

[0029] Specifically, a valve core assembly J2 extending along its central axis is installed inside the main valve chamber J1, and the valve sleeve 3 provides a stable guide path for the valve core 4 to ensure the accuracy of its linear motion; the valve sleeve 3 is a precision-machined cylindrical metal sleeve, which is nested in the main valve chamber J1, and the inner hole forms a dynamic fit with the valve core 4. The valve core 4 is a sliding valve in the translational valve core 4, which is a cylindrical shaft and adopts a clearance fit with the valve sleeve 3. The friction and wear are reduced through hardening treatment to ensure the sensitivity of axial sliding; the precise up and down movement of the valve core 4 in the valve sleeve 3 directly controls the opening and closing of the high-pressure and large-flow directional control valve.

[0030] In a possible embodiment, the lower end of the valve sleeve 3 is opposite to the oil return chamber 102 , and the valve sleeve 3 is radially provided with an oil inlet hole 103 opposite to the oil inlet chamber 101 ; Specifically, the oil inlet hole 103 is connected to the oil inlet chamber 101, and the high-pressure oil is introduced into the internal flow channel of the valve body 1 to provide a power source for the control system. The pressure oil pushes the valve core 4 to move to adjust the opening and closing of the control valve.

[0031] In one possible embodiment, a first valve sleeve seal 2 is provided between the valve sleeve 3 and the main valve chamber J1; the valve core 4 is provided with a valve core sealing ring 405, and the valve core sealing ring 405 divides the inner hole of the valve sleeve 3 into a valve core lower chamber 404 and a valve core upper chamber 406, the valve core lower chamber 404 is connected to the oil inlet chamber 101, and a valve core center hole 401 and a valve core pressure reducing hole 403 are opened on the valve core 4; a valve core buffer structure 402 is provided at the bottom of the valve core 4.

[0032] Specifically, the first valve sleeve seal 2 forms a reliable sealing barrier between the valve sleeve 3 and the main valve chamber J1 to prevent leakage of the fluid medium and ensure pressure stability and fluid control of the system.

[0033] The valve core sealing ring 405 is embedded in the annular groove of the valve core 4 through interference fit. It is a key component for realizing the separation of the fluid chamber, and its structural design directly affects the sealing performance, pressure resistance and service life of the valve. It is known that the valve core lower chamber 404 is directly subjected to the high-pressure medium pressure of the pipeline due to its communication with the oil inlet chamber 101, and has the initial power to push the valve core 4 upward, thereby affecting the dynamic response of the valve. In addition, a valve core center hole 401 and a valve core pressure reducing hole 403 are also provided on the valve core 4, wherein the valve core pressure reducing hole 403 reduces the pressure of the high-pressure oil by reducing the flow cross-sectional area, and the valve core center hole 401 is used to penetrate the valve core to form a normal oil path, and plays a role of continuous pressure relief by communicating with the return oil chamber 102. The valve core pressure reducing hole 403 and the valve core center hole 401 cooperate to generate a pressure difference between the valve core upper chamber 406 and the valve core lower chamber 404, thereby driving the valve core 4 to move upward. A conical throttling groove or a multi-stage annular notch is provided at the bottom of the valve core 4 as a valve core buffer structure 402. The valve core buffer structure 402 controls the gradual change rate of the flow cross-sectional area with the displacement, such as linear or equal percentage characteristics, so that the flow change rate is proportional to the stroke of the valve core 4, thereby realizing the linear opening and closing of the high-pressure and large-flow directional control valve.

[0034] The buffer mechanism of the buffer mechanism during the opening and closing stages of the control valve is as follows: Opening stage: an initial micro-gap is formed between the conical surface at the bottom of the valve core 4 and the valve sleeve 3, and the high-pressure fluid throttles and depressurizes through this gap, reducing the initial impact force; Closed end: The depth of the tapered throttling groove decreases step by step, the flow section contraction rate increases, and a flexible sealing contact is achieved.

[0035] In summary, the valve core buffer structure 402 can not only realize the linear opening and closing adjustment of the control valve, but also effectively reduce the vibration during opening and closing, thereby improving the operating stability and life of the high-pressure and large-flow directional control valve.

[0036] In one possible embodiment, the pilot cover plate 10 is fixedly mounted on the valve body 1; the pilot valve stem 9 is slidably mounted in the pilot cover plate 10 along the central axis direction of the pilot cover plate 10, and a pilot valve stem seal 11 is provided between the pilot cover plate 10 and the pilot valve stem 9. The pilot valve stem seal 11 divides the inner hole of the pilot cover plate 10 into a pilot valve stem lower chamber 1001 and a pilot valve stem upper chamber 1002. When the pilot valve stem lower chamber 1001 is connected to the pilot pressure oil, an upward pressure is generated on the pilot valve stem 9. When the pilot valve stem upper chamber 1002 is connected to the pilot pressure oil, a downward pressure is generated on the pilot valve stem 9, dynamically driving the axial movement of the pilot valve stem 9. The pilot valve stem 9 limits the axial displacement of the valve core 4 by moving up and down.

[0037] Specifically, the pilot cover plate 10 and the pilot valve stem 9 form a precise functional coupling relationship in the hydraulic control system, and the two work together to realize the "small flow controlling large flow" regulation mechanism; the pilot cover plate 10, as a functional carrier, integrates the control flow channel to form the physical installation base of the pilot valve stem 9, ensuring the straightness and sealing of the axial movement; two oblique oil channels are also provided in the pilot cover plate 10 for connecting the pilot pressure oil and the pilot cover plate cavity, wherein the oil channel extending obliquely upward is used to connect the pilot pressure oil and the pilot valve stem upper cavity 1002, and the oil channel extending obliquely downward is used to connect the pilot pressure oil and the pilot valve stem lower cavity 1001, forming two low-pressure control paths; the pilot valve stem 9, as the core transmission element of the hydraulic control system, adopts a column-rod two-part design, the column is connected to the cooperative control mechanism T3 on it, and receives the pressure from the cooperative control mechanism T3, and the rod is connected to the control valve body T1 below it and acts on the valve core 4; In a possible embodiment, the pilot hydraulic adjustment mechanism T2 also includes a guide cover 7, which is installed in the main valve chamber J1 and extends to the lower end of the pilot cover plate 10; a guide hole is opened in the guide cover 7, and the pilot valve stem 9 passes through the guide hole and abuts against the valve core assembly J2; the guide cover 7 is not only provided with a first guide cover seal 6 between the main valve chamber J1, but also with a second guide cover seal 8 between the guide cover 7 and the pilot cover plate 10, and also with a second valve sleeve seal 5 between the guide cover 7 and the valve sleeve 3.

[0038] Specifically, the guide cover 7 is a coaxial rotating body, which covers the valve sleeve 3, and the pilot valve stem 9 is embedded in the guide cover 7 in an inserted form and extends into the control valve body T1; the guide cover 7 structurally plays the role of connecting the control valve body T1 and the pilot hydraulic adjustment mechanism T2, while also constraining the axial movement trajectory of the pilot valve stem 9.

[0039] In a possible implementation, the pilot hydraulic pressure regulating mechanism T2 further includes a pilot connecting plate 19 . The pilot connecting plate 19 is mounted on the pilot cover plate 10 . The pilot valve 20 is fixedly mounted on the pilot cover plate 10 through the pilot connecting plate 19 .

[0040] Specifically, the pilot connecting plate 19 is a key transition component of the pilot hydraulic adjustment mechanism T2. Threaded mounting holes and positioning pin holes are provided on the plate to ensure alignment with the pilot valve 20. The pilot pressure oil can be accurately and efficiently transported from the pilot valve 20 to the pilot cover plate 10 through the pilot connecting plate 19.

[0041] In one possible embodiment, the pilot valve 20 is used to receive an external control signal and input pilot pressure oil to the pilot hydraulic regulating mechanism T2 to control the operation of the pilot hydraulic regulating mechanism T2. The pilot pressure oil is connected to the P cavity of the pilot valve 20 through the internal oil circuit of the valve body 1, the pilot cover plate 10 and the pilot connecting plate 19. The pilot valve 20 can control the connection and switching of the pilot pressure oil with the lower cavity 1001 of the pilot valve stem and the upper cavity 1002 of the pilot valve stem.

[0042] Specifically, the pilot pressure oil source comes from the hydraulic system control circuit. The main pressure oil is diverted to the pilot hydraulic adjustment mechanism T2 through the internal flow channel, and then flows through the internal channel of the pilot cover plate 10 and the pilot connecting plate 19 and finally enters the P chamber of the pilot valve 20. In one possible implementation, the elasticity control component J3 includes: The spring pressure cover 13 is fixedly mounted on the pilot cover 10 , and a spring pressure cover seal 12 is installed between the spring pressure cover 13 and the pilot cover 10 ; Spring 14, spring 14 is installed inside the upper cavity 1002 of the pilot valve stem; Spring washer 15, spring washer 15 is installed inside the upper cavity 1002 of the pilot valve stem; The spring 14 cooperates with the pilot pressure oil to control the axial movement of the pilot valve stem 9 .

[0043] Specifically, the spring pressure cover 13 adopts a circular contour design, which is precisely matched with the upper part of the pilot cover plate 10, and has an embedded spring 14, which is rigidly connected to the base through threads or snaps; the preload force of the spring 14 in the control valve is downward, which can keep the high-pressure and high-flow directional control valve in a closed state under normal circumstances.

[0044] In a possible embodiment, the cooperative control mechanism T3 further includes: an adjusting rod 17 and a lock nut 18, the adjusting rod 17 is threadedly mounted on the spring pressure cover 13, and an adjusting rod seal 16 is provided between the adjusting rod 17 and the spring pressure cover 13; A locknut 18 is mounted on the adjusting rod 17; The regulating rod 17 adjusts the maximum stroke S2 ​​of the pilot valve stem 9 through the limitation of the anti-loosening nut 18, thereby controlling the opening degree of the valve port of the high-pressure and large-flow directional control valve.

[0045] Specifically, the coordinated design of the adjusting rod 17 and the anti-loosening nut 18 is the core guarantee for achieving precise fluid control and long-term operational stability; after the adjusting rod 17 completes the opening setting, the anti-loosening nut 18 fixes the rod through a preset pre-tightening force, which can avoid slight deviations caused by changes in external loads.

[0046] When the high-pressure, high-flow directional control valve involved in the present invention is used, the method for using the high-pressure, high-flow directional control valve includes the following steps: S1: When the high-pressure, high-flow directional control valve is normally in the closed state and the pilot valve 20 is in the power-off state, the pilot pressure oil is connected to the upper chamber 1002 of the pilot valve stem, and the pilot valve stem 9 is subjected to the downward pressure of the pilot pressure oil, the downward elastic force of the spring 14 and the upward force of the valve core 4 on the pilot valve stem 9. The sum of the pressure of the pilot pressure oil and the elastic force of the spring 14 is greater than the upward force of the valve core 4 on the pilot valve stem 9. At this time, the pilot valve stem 9 is in the lowest position and the high-pressure, high-flow directional control valve is in the closed state.

[0047] S2: When the pilot valve 20 is energized by a signal, the pilot pressure oil communicates with the lower chamber 1001 of the pilot valve stem. The pilot valve stem 9 is subjected to the upward pressure of the pilot pressure oil, the downward force of the spring 14, and the upward force exerted on the pilot valve stem 9 by the valve core 4. The pressure of the pilot pressure oil is greater than the spring 14, and the pilot valve stem 9 is in the uppermost position. At this time, the position of the valve core 4 is independent of the pilot valve stem 9. The pressure in the valve body oil inlet chamber 101 is greater than the pressure in the valve body oil return chamber 102. Due to the presence of the valve core center hole 401 and the valve core pressure reducing hole 403, the pressure in the valve core upper chamber 406 is less than the pressure in the valve core lower chamber 404. The upward force of the pressurized liquid causes the valve core 4 to move upward, and the valve core 4 opens. S3: When the pilot valve 20 is de-energized by the signal, the force on the pilot valve stem 9 is the same as in S1. The pilot valve stem 9 moves downward under the action of the combined force, pushing the valve core 4 downward to the lowest position of the valve core 4, and the high-pressure and high-flow directional control valve returns to the closed state. Here, the downward pressure F1 of the pilot oil pressure = pilot oil pressure P × cross-sectional area A1 of the pilot valve stem upper chamber 1002; the upward force F2 exerted by the valve core 4 on the pilot valve stem 9 = the pressure difference ∆P between the valve core lower chamber 404 and upper chamber 406 × cross-sectional area A2 of the valve core upper chamber 406. In the present invention, the cross-sectional area A1 of the pilot valve stem upper chamber 1002 is greater than the cross-sectional area A2 of the valve core upper chamber 406. Due to the presence of the valve core pressure relief hole 403, ∆P is relatively small. Therefore, a relatively small pilot oil pressure P can be used to close the high-pressure, high-flow directional control valve, achieving the goal of controlling high pressure with low pressure.

[0048] S4: When the pilot valve fails, there is no pressure in the upper chamber 1002 and the lower chamber 1001 of the pilot valve stem. The pilot valve stem 9 is in the lowest position under the elastic force of the spring 14, and the high-pressure and high-flow directional control valve is in the closed state.

[0049] S5: The movable stroke of the valve core 4 is limited by the maximum allowable stroke S1 of the valve core 4 and the maximum stroke S2 ​​of the pilot valve stem 9. The maximum stroke S2 ​​of the pilot valve stem 9 can be adjusted by the adjusting rod 17. When S2 is greater than S1, the movable stroke of the valve core 4 is S1. When S2 is less than S1, the movable stroke of the valve core 4 is S2.

[0050] The maximum allowable stroke S1 of the valve core 4 is the height difference between the valve sleeve 3 and the valve core 4. Its value is unique and fixed in a high-pressure, high-flow directional control valve. The maximum stroke S2 ​​of the pilot valve stem 9 is the distance between the uppermost end of the pilot valve stem 9 and the lowermost end of the adjusting rod 17 when the pilot valve stem 9 is in its lowest position. This distance is determined by the position of the adjusting rod 17. Similarly, the relationship between S1 and S2 is also determined by the position of the adjusting rod 17. At this point, there is a critical height: critical height = height of the uppermost end of the pilot valve stem 9 when the pilot valve stem 9 is in its lowest position + S1. When the lowermost end of the adjusting rod 17 is above the critical height, S2 is greater than S1, and the movable stroke of the valve core 4 is S1. When the lowermost end of the adjusting rod 17 is below the critical height, S2 is less than S1, and the movable stroke of the valve core 4 is S2.

[0051] The normally closed, high-pressure, high-flow directional control valve structure disclosed herein can be used to control the opening and closing of the high-pressure, high-flow directional control valve using low-pressure pilot oil. Furthermore, the valve opening degree can be controlled by adjusting the lever 17, resulting in a simple structure and high safety and stability. Furthermore, a valve core buffer structure 402 provided at the bottom of the valve core 4 enables linear opening and closing, reducing vibration during opening and closing, effectively improving the operational stability and lifespan of the high-pressure, high-flow directional control valve.

[0052] It will be easily understood by those skilled in the art that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A normally closed high pressure and large flow directional control valve, characterized in that: include: A control valve body (T1), the control valve body (T1) comprising a valve body (1) and a valve core assembly (J2), the valve body (1) having an oil inlet chamber (101) and an oil return chamber (102), the valve body (1) being connected to a hydraulic system via the oil inlet chamber (101) and the oil return chamber (102), the valve core assembly (J2) being movably disposed within the valve body (1) to control the opening and closing degrees of the oil inlet chamber (101) and the oil return chamber (102), thereby controlling the direction, flow rate and pressure of the hydraulic system; a pilot hydraulic pressure regulating mechanism (T2), arranged at the upper end of the control valve body (T1), the pilot hydraulic pressure regulating mechanism (T2) being connected to the valve core assembly (J2) and acting on the valve core assembly (J2) to activate the valve core assembly (J2); a pilot valve (20) connected to the pilot hydraulic regulating mechanism (T2), the pilot valve (20) being used to receive an external control signal and input pilot pressure oil to the pilot hydraulic regulating mechanism (T2) to control the operation of the pilot hydraulic regulating mechanism (T2); A collaborative control mechanism (T3) is provided with an elastic control component (J3), and the elastic control component (J3) is connected to the pilot hydraulic adjustment mechanism (T2) to cooperate with the pilot hydraulic adjustment mechanism (T2) to act on the valve core component (J2).

2. The normally closed high-pressure and large-flow directional control valve according to claim 1, characterized in that: A main valve chamber (J1) extending along its central axis is provided in the valve body (1); the oil inlet chamber (101) is provided along the horizontal direction of the valve body (1) and communicates with the main valve chamber (J1); the oil return chamber (102) is provided along the vertical direction of the valve body (1) and communicates with the main valve chamber (J1); the oil inlet chamber (101) and the oil return chamber (102) are perpendicular to each other; The valve core assembly (J2) is arranged in the main valve chamber (J1) and is located between the oil inlet chamber (101) and the oil return chamber (102).

3. The normally closed high-pressure and large-flow directional control valve according to claim 2, characterized in that: The valve core assembly (J2) includes a valve core (4) and a valve sleeve (3); The valve sleeve (3) is fixedly mounted inside the main valve chamber (J1), and the valve core (4) is slidably arranged inside the valve sleeve (3); The pilot hydraulic pressure regulating mechanism (T2) is connected to the valve core (4) to act on the valve core (4).

4. The normally closed high-pressure and large-flow directional control valve according to claim 3, characterized in that: The lower end of the valve sleeve (3) is opposite to the oil return chamber (102), and the valve sleeve (3) is radially provided with an oil inlet hole (103) opposite to the oil inlet chamber (101); the valve core (4) moves between the lower end of the valve sleeve (3) and the oil inlet hole (103) to control the opening and closing degree of the oil inlet chamber (101) and the oil return chamber (102).

5. The normally closed high-pressure and large-flow directional control valve according to claim 3, characterized in that: A first valve sleeve seal (2) is provided between the valve sleeve (3) and the main valve chamber (J1); The valve core (4) is provided with a valve core sealing ring (405), and the valve core sealing ring (405) divides the inner hole of the valve sleeve (3) into a valve core lower chamber (404) and a valve core upper chamber (406). The valve core lower chamber (404) is communicated with the oil inlet chamber (101). The valve core (4) is provided with a valve core center hole (401) and a valve core pressure reducing hole (403); the valve core bottom is provided with the valve core buffer structure (402).

6. The normally closed high-pressure and large-flow directional control valve according to claim 1, characterized in that: The pilot hydraulic pressure regulating mechanism (T2) comprises: A pilot cover plate (10), the pilot cover plate (10) being fixedly mounted on the valve body (1); A pilot valve stem (9), the pilot valve stem (9) being slidably mounted in the pilot cover plate (10) along the central axis direction of the pilot cover plate (10); A pilot valve stem seal (11) is provided between the pilot cover plate (10) and the pilot valve stem (9), and the pilot valve stem seal (11) divides the inner hole of the pilot cover plate (10) into a pilot valve stem lower chamber (1001) and a pilot valve stem upper chamber (1002); When the lower chamber (1001) of the pilot valve stem is connected to the pilot pressure oil, an upward pressure is generated on the pilot valve stem (9); when the upper chamber (1002) of the pilot valve stem is connected to the pilot pressure oil, a downward pressure is generated on the pilot valve stem (9), dynamically driving the axial movement of the pilot valve stem (9); the pilot valve stem (9) limits the axial displacement of the valve core (4) by moving up and down.

7. The normally closed high-pressure and large-flow directional control valve according to claim 3, characterized in that: The pilot hydraulic pressure regulating mechanism (T2) further comprises: A guide cover (7), the guide cover (7) is installed inside the main valve cavity (J1) and extends to the lower end of the pilot cover plate (10); a guide hole is opened in the guide cover (7), and the pilot valve stem (9) passes through the guide hole and abuts against the valve core assembly (J2); A first guide cover seal (6) is provided between the guide cover (7) and the main valve chamber (J1), a second guide cover seal (8) is provided between the guide cover (7) and the pilot cover plate (10), and a second valve sleeve seal (5) is provided between the guide cover (7) and the valve sleeve (3).

8. The normally closed high-pressure and large-flow directional control valve according to claim 6, characterized in that: The pilot hydraulic pressure regulating mechanism (T2) further comprises: A pilot connecting plate (19), wherein the pilot connecting plate (19) is mounted on the pilot cover plate (10), and the pilot valve (20) is fixedly mounted on the pilot cover plate (10) via the pilot connecting plate (19).

9. The normally closed high-pressure and large-flow directional control valve according to claim 1, characterized in that: The elastic control component (J3) includes: A spring pressure cover (13), wherein the spring pressure cover (13) is fixedly mounted on the pilot cover plate (10), and a spring pressure cover seal (12) is mounted between the spring pressure cover (13) and the pilot cover plate (10); A spring (14), the spring (14) being installed inside the upper chamber (1002) of the pilot valve stem; A spring washer (15), the spring washer (15) being installed inside the upper cavity (1002) of the pilot valve stem; The spring (14) cooperates with the pilot pressure oil to control the axial movement of the pilot valve stem (9).

10. The normally closed high-pressure and large-flow directional control valve according to claim 1, characterized in that: The collaborative control mechanism (T3) further includes: An adjusting rod (17), wherein the adjusting rod (17) is threadedly mounted on the spring pressure cover (13), and an adjusting rod seal (16) is provided between the adjusting rod (17) and the spring pressure cover (13); a locking nut (18), the locking nut (18) being mounted on the adjusting rod (17); The regulating rod (17) adjusts the maximum stroke S2 ​​of the pilot valve rod (9) through the limitation of the anti-loosening nut (18) to control the opening degree of the valve port of the high-pressure and high-flow directional control valve.

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