Control valve and hydraulic cylinder control system

Abstract

The application discloses a control valve and a hydraulic cylinder control system, the control valve comprises a valve body, a main valve core, a back liquid valve core, a pilot valve group and a driving part, the back liquid valve core is movable in an inner cavity to adjust the opening degree of a back liquid port of the main valve core and the opening degree of a liquid inlet port of the main valve core, the driving part drives the pilot valve group to move in the inner cavity of the valve body and drives the back liquid valve core to follow, a first cavity is arranged between one end of the back liquid valve core away from the main valve core and the valve body, a flow channel is arranged in the back liquid valve core, and the flow channel is used for connecting the first cavity and a working medium chamber of the main valve core to balance the hydraulic pressure of both ends of the back liquid valve core in the moving direction. The control valve can realize continuous adjustment of the opening degree of the valve core, improve the control precision of the inlet and back liquid flow, reduce the hydraulic imbalance force of the valve core, and then reduce the valve port opening and closing pressure impact, improve the control precision of the hydraulic cylinder and improve the stability of the system.

Description

Technical Field

[0001] This invention belongs to the field of control valve technology, specifically relating to a control valve and hydraulic cylinder control system. Background Technology

[0002] The coal mining face consists of multiple hydraulic supports arranged sequentially, each connected to the chute by a pushing jack. Besides supporting the roof of the working face, the hydraulic supports also move and push the chute. In underground coal mines, hydraulic supports support the roof through their own positional shifting and attitude adjustment, providing a safe working space for underground personnel and coal mining equipment.

[0003] With the improvement of the level of intelligent coal mining, higher requirements are put forward for the hydraulic system of hydraulic supports. In the current hydraulic system, the valve core position control accuracy of the control valve is low, and the vibration and impact resistance is insufficient when subjected to uncertain load disturbances.

[0004] For example, CN109555740A proposes a water-based proportional valve and its control method. The main valve core, pilot inlet valve core, and pilot return valve core require three-core follow-up, employing an asynchronous follow-up control principle. The position of the main valve core is directly fed back to the opening of the pilot valve. When the main valve core is subjected to uncertain load disturbances, the position fluctuation of the main valve core will cause the pilot valve to open. Therefore, in this case, the position of the inlet valve core has insufficient anti-disturbance capability. Another example is CN111894924A, which proposes a high-pressure, high-flow digital proportional directional valve with manual / automatic integrated control. The feedback groove on the inner surface of the valve sleeve mainly reflects pressure. The pressure in the pilot chamber is controlled jointly by the high-speed switching valve and the feedback groove, making control relatively difficult and resulting in low position control accuracy for the inlet valve core. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, embodiments of the present invention propose a control valve that can continuously adjust the valve core opening, improve the control accuracy of the inlet and outlet fluid flow rates, and at the same time reduce the pressure shock of valve opening and closing, thereby improving the control accuracy of the hydraulic cylinder.

[0007] Embodiments of the present invention also propose a hydraulic cylinder control system.

[0008] A control valve according to an embodiment of the present invention includes:

[0009] Valve body, the valve body having an internal cavity;

[0010] A main valve core and a return valve core are provided in the inner cavity. The return valve core is movable in the inner cavity and has a first displacement state and a second displacement state. In the first displacement state, the return valve core is separated from the main valve core and moves relative to the main valve core to adjust the opening of the return port of the main valve core. In the second displacement state, the return valve core abuts against the main valve core and moves synchronously with the main valve core to adjust the opening of the inlet port of the main valve core.

[0011] A pilot valve assembly is disposed in the inner cavity and is connected to the return valve core;

[0012] A drive unit is connected to the pilot valve assembly to drive the pilot valve assembly to move within the inner cavity of the valve body and cause the return valve core to move accordingly.

[0013] The return valve core has a first cavity between its end away from the main valve core and the valve body. The return valve core has a flow channel inside, which is used to connect the first cavity and the working medium chamber of the main valve core to balance the hydraulic pressure at both ends of the return valve core in the direction of movement.

[0014] The control valve of this invention can continuously adjust the valve core opening through the pilot valve assembly, thereby improving the control accuracy of the inlet and outlet fluid flow. Through the design of the flow channel, the hydraulic imbalance force of the valve core can be reduced, which can reduce the pressure impact of valve opening and closing, improve the control accuracy of the hydraulic cylinder, and improve the stability of the system.

[0015] In some embodiments, the pressure-bearing area of ​​the side of the return valve core away from the main valve core is equal to the cross-sectional area of ​​the working port end of the main valve core; and / or

[0016] The drive unit includes a digital motor, which receives a displacement command equivalent signal from the control unit to control the operation of the pilot valve assembly; and / or

[0017] The control valve further includes a reset component, which is disposed on the pilot valve assembly and is used to reset the pilot valve assembly; and / or

[0018] The control valve also includes an emergency power supply, which is connected to the drive unit.

[0019] In some embodiments, the pilot valve assembly includes:

[0020] A pilot valve sleeve is disposed in the inner cavity and is movable in the inner cavity. The pilot valve sleeve is connected to the return valve core. A second cavity and a third cavity are provided between the pilot valve sleeve and the valve body. The second cavity and the third cavity have a pressure difference to drive the pilot valve sleeve to move in the inner cavity. The pilot valve sleeve has a fourth cavity.

[0021] A pilot valve core is disposed in the fourth cavity, and a fifth cavity is provided between the pilot valve core and the side wall of the fourth cavity. The pilot valve core is movable in the fourth cavity so that the fifth cavity communicates with one of the second cavity and the third cavity. The fifth cavity is used to depressurize the second cavity or the third cavity to adjust the pressure difference between the second cavity and the third cavity.

[0022] The drive unit is used to drive the pilot valve core to move in the fourth chamber.

[0023] In some embodiments, the valve body is provided with a first oil port, a second oil port and a third oil port. The first oil port is connected to the second cavity, the second oil port is connected to the third cavity, and the third oil port is connected to the fifth cavity. The first oil port and the second oil port are used to supply oil to the second cavity and the third cavity respectively, and the third oil port is used to return oil.

[0024] In some embodiments, the main valve core, the return valve core, the pilot valve sleeve, and the pilot valve core are arranged coaxially and all move along the axial direction; and / or

[0025] The valve body includes a first valve body and a second valve body, wherein one end of the first valve body is provided with an end cap, and the second valve body is provided at the other end of the first valve body; and / or

[0026] The drive unit has a drive rod connected to the pilot valve core, and the drive unit is used to drive the pilot valve core to move linearly reciprocally; and / or

[0027] It also includes a first spring disposed between the pilot valve spool and the pilot valve sleeve, for driving the pilot valve spool to reset; and / or

[0028] Both the first and second oil ports are equipped with damping screw plugs; and / or

[0029] The pilot valve sleeve has a sixth chamber, which is connected to the third oil port and the fifth chamber. During the movement of the pilot valve core and the pilot valve sleeve, the fifth chamber, the sixth chamber and the third oil port are always connected.

[0030] In some embodiments, the main valve core includes:

[0031] The valve stem has the working medium chamber, the inlet is located on the side wall of the valve stem, the return port is located at one end of the valve stem, and the working oil port of the main valve core is located at the other end of the valve stem.

[0032] A first ring body is disposed on the outer wall of the valve stem. The valve body is provided with a fourth oil port and a fifth oil port. The fourth oil port is used to supply oil to the inlet port, and the fifth oil port is used to return oil to the return port. A first sealing gasket is provided in the inner cavity. A second spring is provided between the first ring body and the valve body. The second spring is used to drive the first ring body to abut against the first sealing gasket to block the fourth oil port and the inlet port.

[0033] In some embodiments, the first ring body has a first chamfer, the first sealing gasket has a second chamfer, and the first ring body and the first sealing gasket are sealed by abutting against each other through the first chamfer and the second chamfer; and / or

[0034] It also includes a positioning ring disposed in the inner cavity, the valve stem being slidably sleeved in the positioning ring, and a liquid inlet cavity being formed between the outer wall surface of the valve stem and the inner wall surface of the inner cavity of the valve body. The first ring and the first sealing gasket are located in the liquid inlet cavity, and the fourth oil port and the liquid inlet are connected through the liquid inlet cavity. When the first ring and the first sealing gasket abut against each other, the fourth oil port is connected to the liquid inlet cavity on the side of the first ring away from the liquid inlet, and the positioning ring is correspondingly arranged to the liquid inlet in the axial direction of the valve stem; and / or

[0035] The return valve core is provided with a second sealing gasket and a connector. In the second displacement state, the end of the valve stem abuts against the second sealing gasket to block the return port. The connector is provided with a third chamfer. The third chamfer and the end of the valve stem are arranged opposite to each other. In the first displacement state, the third chamfer and the valve stem open and close relative to each other to adjust the opening degree of the return port.

[0036] The hydraulic cylinder control system of this invention includes:

[0037] A hydraulic cylinder, wherein the hydraulic cylinder is connected to a first oil circuit and a second oil circuit;

[0038] The first valve and the second valve are both control valves as described in any of the above embodiments, wherein one of the first valve and the second valve is provided in the first oil circuit and the other is provided in the second oil circuit;

[0039] A detection unit is used to monitor the position of the hydraulic cylinder;

[0040] The control unit is used to receive monitoring data from the detection unit and control the operation of the first valve and the second valve.

[0041] In some embodiments, the hydraulic cylinder control system includes the following steps in use:

[0042] Obtain the target change of the hydraulic cylinder;

[0043] Read the current position value of the hydraulic cylinder, calculate and give the corresponding action signal;

[0044] The first valve and the second valve operate according to the action signal to control the extension and retraction of the hydraulic cylinder;

[0045] Calculate whether the position deviation of the hydraulic cylinder is greater than the first threshold. If not, end the action.

[0046] If so, repeat the above steps.

[0047] In some embodiments, during use, the hydraulic cylinder control system further includes the following steps: detecting whether the hydraulic cylinder pressure and position information are normal; if so, executing the action of the hydraulic cylinder control system; if not, stopping the action and issuing an alarm; and / or

[0048] The hydraulic cylinder control system also includes an emergency power supply, which is used to supply power in the event of a power outage. In use, the hydraulic cylinder control system further includes the following steps: detecting whether there is a power outage; if so, activating the emergency power supply; if not, executing the actions of the hydraulic cylinder control system. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the control valve structure according to an embodiment of the present invention.

[0050] Figure 2 This is a schematic diagram of the control valve structure according to another embodiment of the present invention.

[0051] Figure 3 This is a schematic diagram of the control valve structure according to another embodiment of the present invention.

[0052] Figure 4 This is a schematic diagram of the control valve structure according to another embodiment of the present invention.

[0053] Figure 5 This is a schematic diagram of the control valve according to an embodiment of the present invention.

[0054] Figure 6 This is a schematic diagram of the hydraulic cylinder control system according to an embodiment of the present invention.

[0055] Figure 7 This is a flowchart of the hydraulic cylinder control system according to an embodiment of the present invention.

[0056] Figure label:

[0057] 1. Valve body; 11. First valve body; 12. Second valve body; 13. End cap; 14. First oil port; 141. Damping screw plug; 15. Second oil port; 16. Third oil port; 17. Fourth oil port; 18. Fifth oil port; 19. Liquid inlet chamber;

[0058] 2. Main valve core; 21. Valve stem; 22. First ring; 221. First chamfer; 23. First sealing gasket; 231. Second chamfer; 24. Liquid inlet; 25. Liquid return port; 26. Second spring; 27. Positioning ring;

[0059] 3. Return valve core; 31. Second sealing gasket; 32. Connecting piece; 321. Third chamfer; 33. Flow channel; 34. First chamber;

[0060] 4. Pilot valve sleeve; 41. Second chamber; 42. Third chamber; 43. Sixth chamber; 44. First connecting hole; 45. Second connecting hole; 46. Third connecting hole;

[0061] 5. Pilot valve core; 51. Fifth chamber; 52. First spring; 53. Glyd ring;

[0062] 6. Drive unit; 61. Drive rod;

[0063] 71. Hydraulic cylinder; 72. First valve; 73. Second valve; 74. Emergency power supply. Detailed Implementation

[0064] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0065] like Figures 1-5 As shown, the control valve of this embodiment of the invention is a pilot-operated follow-up two-position three-way proportional directional valve, including a valve body 1, which has an inner cavity.

[0066] The inner cavity is provided with a main valve core 2 and a return valve core 3. The return valve core 3 is movable in the inner cavity and has a first displacement state and a second displacement state. In the first displacement state, the return valve core 3 is separated from the main valve core 2 and moves relative to the main valve core 2 to adjust the opening of the return port 25 of the main valve core 2. In the second displacement state, the return valve core 3 abuts against the main valve core 2 and moves synchronously with the main valve core 2 to adjust the opening of the inlet port 24 of the main valve core 2.

[0067] The inner cavity is also provided with a pilot valve assembly and a drive unit 6. The pilot valve assembly is connected to the return valve core 3, and the drive unit 6 is connected to the pilot valve assembly to drive the pilot valve assembly to move in the inner cavity of the valve body 1 and make the return valve core 3 move accordingly.

[0068] The return valve core 3 has a first cavity 34 between the end away from the main valve core 2 and the valve body 1. The return valve core 3 has a flow channel 33 inside, which is used to connect the first cavity 34 and the working medium chamber of the main valve core 2 to balance the hydraulic pressure at both ends of the return valve core 3 in the moving direction.

[0069] Specifically, the inner cavity is equipped with a main valve core 2 and a return valve core 3. Both the main valve core 2 and the return valve core 3 are movable within the inner cavity of the valve body 1. By controlling the positions of the main valve core 2 and the return valve core 3 within the valve body 1, the opening degree of the inlet 24 and the return port 25 of the main valve core 2 can be controlled, achieving the purpose of linear adjustment of the opening degree of the inlet 24 and the return port 25. The return valve core 3 has a first displacement state and a second displacement state. In the first displacement state, the return valve core 3 is separated from the main valve core 2, and the movement of the return valve core 3 will not drive the main valve core 2 to move. When the return valve core 3 moves relative to the main valve core 2, it can adjust the opening degree of the return port 25. In the second displacement state, the return valve core 3 abuts against the main valve core 2, and the return valve core 3 moves synchronously with the main valve core 2. When the return valve core 3 moves, it can adjust the opening degree of the inlet 24.

[0070] For example, the return valve core 3 reciprocates between the first and second limit positions in the valve body 1. When the return valve core 3 moves from the first limit position to the second limit position, the opening of the return port 25 decreases linearly to the closed state, and then the opening of the inlet port 24 increases linearly. When the return valve core 3 moves from the second limit position to the first limit position, the opening of the inlet port 24 decreases linearly to the closed state, and then the opening of the return port 25 increases linearly.

[0071] Figure 1 The diagram shows the state when the return valve core 3 is in the leftmost position, that is, in the first extreme position. Figure 2 The diagram shows the state of the return valve core 3 during its rightward movement. Taking the process of the return valve core 3 moving from the first extreme position to the second extreme position as an example, the entire stroke of the return valve core 3 can be divided into two segments. In the first segment (i.e., the first displacement state), the return valve core 3 is not in contact with the main valve core 2. The return valve core 3 gradually approaches the main valve core 2, and the return port 25 is in the open state. The main valve core 2 is in the initial state at this time, and the inlet port 24 is closed. As the return valve core 3 continues to approach the main valve core 2, the opening of the return port 25 decreases linearly until the return valve core 3 and the main valve core 2 come into contact. At this time, the return port 25 is closed. In the second segment (i.e., the second displacement state), the return valve core 3 comes into contact with the main valve core 2. At this time, the return port 25 is in the closed state, and the inlet port 24 will gradually open as the return valve core 3 pushes against the main valve core 2. The opening of the inlet port 24 increases linearly, realizing linear control from return to inlet.

[0072] Furthermore, if the pressure-bearing area of ​​the side of the return valve core 3 away from the main valve core 2 is the same as the cross-sectional area of ​​the working oil port end of the main valve core 2, then the pressure balance adjustment can be better achieved.

[0073] like Figure 3 As shown, in this embodiment of the invention, the return valve core 3 and the main valve core 2 are hydraulically balanced through a flow channel. When the return valve core 3 abuts against the main valve core 2, the return port is closed. At this time, the main valve core 2 and the return valve core 3 move synchronously, and the right side of the main valve core 2 is subjected to a hydraulic thrust F1 = P. A *S3, the left side of the return valve core 3 is subjected to a hydraulic balancing force F2=P A *(S1-S2), where P A This refers to pressure.

[0074] Since S1-S2=S3, the hydraulic pressure balance between the two is used to reduce the pilot drive resistance and improve the response speed of the main valve core 2. At this time, the movement of the main valve core 2 is only affected by friction, thus improving the response speed of the main valve core 2. In addition, when the main valve core 2's return port or inlet port is kept open, the flow channel design achieves force balance at both ends of the return valve core 3. Therefore, the drive unit 6 only needs to provide a small holding force.

[0075] In some embodiments, the drive unit 6 includes a digital motor, which is used to receive a displacement command equivalent signal issued by the control unit to control the operation of the pilot valve assembly.

[0076] When driving the pilot valve assembly to move, the extension and retraction accuracy of the digital motor can reach 0.01mm. Therefore, the extension and retraction displacement of the pilot valve assembly and the extension and retraction displacement of the main valve core 2 can both achieve an extension and retraction of 0.01mm.

[0077] The digital motor of this invention can control the extension and retraction position of the hydraulic cylinder piston rod by means of digital signal control, and realize digital signal position closed-loop control, which has the characteristics of easy communication and high position accuracy.

[0078] Furthermore, after the system is powered off, the nut of the rotatable motor replaces the motor thrust to control the valve core to reciprocate.

[0079] In some embodiments, the control valve further includes a reset component, which is disposed on the pilot valve assembly and is used to reset the pilot valve assembly to achieve power failure protection in the event of a system power failure.

[0080] like Figure 4 As shown, in some embodiments, the control valve also includes an emergency power supply connected to the drive unit. The emergency power supply can supply power to the drive unit in the event of a system power failure, thereby enabling the control valve to operate and achieving power failure protection.

[0081] In some embodiments, the pilot valve assembly includes a pilot valve sleeve 4 disposed in the inner cavity. The pilot valve sleeve 4 is movable in the inner cavity and is connected to the return valve core 3. For example, the pilot valve sleeve 4 and the return valve core 3 are connected together by threads, or the pilot valve sleeve 4 and the return valve core 3 are connected together by fasteners such as bolts. A second cavity 41 and a third cavity 42 are provided between the pilot valve sleeve 4 and the valve body 1. The second cavity 41 and the third cavity 42 have a pressure difference to drive the pilot valve sleeve 4 to move in the inner cavity.

[0082] Specifically, the middle part of the pilot valve sleeve 4 slides and fits against the inner cavity of the valve body 1 and is sealed by a sealing ring. The two ends of the pilot valve sleeve 4 are provided with stepped countersunk platforms, which form a second cavity 41 and a third cavity 42 between the countersunk platforms and the inner cavity of the valve body 1. Both the second cavity 41 and the third cavity 42 are connected to oil supply lines, and working medium with a certain pressure is supplied to the second cavity 41 and the third cavity 42 through the oil supply lines. When there is no pressure difference between the second cavity 41 and the third cavity 42, the pilot valve sleeve 4 does not move relative to the valve body 1. When there is a pressure difference between the second cavity 41 and the third cavity 42, the pilot valve sleeve 4 can move in the inner cavity until the pressure in the second cavity 41 and the third cavity 42 reaches equilibrium again.

[0083] Under normal conditions, the pressure of the working medium in the second chamber 41 and the third chamber 42 is the same, and the pilot valve sleeve 4 does not move. At the same time, the return valve core 3 and the main valve core 2 also do not move. When one of the second chamber 41 and the third chamber 42 is depressurized, the pilot valve sleeve 4 will move in the direction of reduced pressure, and at the same time, it will push the return valve core 3 to move, thereby controlling the opening of the return port 25 or the opening of the inlet port 24.

[0084] The pilot valve sleeve 4 has a fourth chamber located in the middle of the pilot valve sleeve 4. A pilot valve core 5 is disposed in the fourth chamber. A fifth chamber 51 is provided between the outer wall of the pilot valve core 5 and the side wall of the fourth chamber. The pilot valve core 5 is movable in the fourth chamber so that the fifth chamber 51 communicates with one of the second chamber 41 and the third chamber 42. The fifth chamber 51 is used to depressurize the second chamber 41 or the third chamber 42 to adjust the pressure difference between the second chamber 41 and the third chamber 42. In this embodiment, the driving unit 6 is used to drive the pilot valve core 5 to move in the fourth chamber. In the direction of movement of the pilot valve core 5, the second chamber 41 and the third chamber 42 are located at both ends of the fifth chamber 51. A Gladius ring 53 is provided on the pilot valve core 5. When the pilot valve core 5 moves to the right in the fourth chamber of the pilot valve sleeve 4, the fifth chamber 51 communicates with the third chamber 42. When the pilot valve core 5 moves to the left in the fourth chamber of the pilot valve sleeve 4, the fifth chamber 51 communicates with the second chamber 41.

[0085] In the initial relative positions of the pilot valve core 5 and the pilot valve sleeve 4, the fifth chamber 51 is not connected to either the second chamber 41 or the third chamber 42, and the pressure in the second chamber 41 and the third chamber 42 remains balanced. Figure 1The state of the control valve is shown. When the control valve is activated, the drive unit 6 drives the pilot valve core 5 to move in the fourth chamber, changing the relative position of the pilot valve core 5 and the pilot valve sleeve 4. The position of the fifth chamber 51 relative to the pilot valve sleeve 4 also moves and connects with the second chamber 41 or the third chamber 42. In this embodiment, the fifth chamber 51 is used to depressurize the second chamber 41 and the third chamber 42. The fifth chamber 51 is connected to the return oil line. When the fifth chamber 51 is connected to one of the second chamber 41 and the third chamber 42, a pressure difference is generated in the second chamber 41 and the third chamber 42, causing the pilot valve sleeve 4 to move relative to the valve body 1 until the pilot valve sleeve 4 and the pilot valve core 5 return to their initial relative positions. At this time, the fifth chamber 51 is not connected to either the second chamber 41 or the third chamber 42, and the pilot valve sleeve 4 no longer moves relative to the valve body 1. Figure 2 As shown in the state of the control valve, after the pilot valve core 5 moves a certain distance to the right, the pilot valve sleeve 4 also completes the follow-up and restores balance.

[0086] During the process described above, where the pilot valve sleeve 4 moves along with the pilot valve core 5, the return valve core 3 will move synchronously with the pilot valve sleeve 4.

[0087] The pilot valve core 5 is driven by the drive unit 6 and can stop at any position during the stroke. Due to the follow-up characteristics, the pilot valve sleeve 4 and the return valve core 3 will also move and stop accordingly. The inlet 24 and return port 25 of the main valve core 2 can be adjusted to any degree, thereby achieving the purpose of linear flow regulation.

[0088] The movement of the pilot valve core 5 only needs to overcome friction. Since the friction between the pilot valve core 5 and the pilot valve sleeve 4 is small, the position of the pilot valve sleeve 4 remains unchanged at the moment the drive unit 6 pushes the pilot valve core 5 to move. When the pressure of the second chamber 41 and the third chamber 42 is unbalanced, the forces on both sides of the pilot valve sleeve 4 are unbalanced, and the pilot valve sleeve 4 moves with the pilot valve core 5. The response time of the pilot valve sleeve 4 and the pilot valve core 5 following the movement is very short.

[0089] In some embodiments, the main valve core 2, the return valve core 3, the pilot valve sleeve 4, and the pilot valve core 5 are arranged coaxially and all move along the axial direction.

[0090] In some embodiments, the valve body 1 includes a first valve body 11 and a second valve body 12, with an end cap 13 at one end of the first valve body 11 and the second valve body 12 at the other end of the first valve body 11.

[0091] To ensure that the main valve core 2, return valve core 3, pilot valve sleeve 4, and pilot valve core 5 operate independently without interference, the inner cavity of the valve body 1 has two relatively independent chambers. The pilot valve sleeve 4 and pilot valve core 5 are arranged in one independent chamber, while the main valve core 2 and return valve core 3 are arranged in the other independent chamber. Specifically, the first valve body 11 and the second valve body 12 are arranged coaxially, and the end cap 13 is located at the left end of the first valve body 11. The first valve body 11 and the end cap 13, and the first valve body 11 and the second valve body 12 are connected together by threads. The chambers of the first valve body 11 and the second valve body 12 form the inner cavity of the valve body 1. A shoulder is provided in the cavity of the first valve body 11, which divides the inner cavity of the valve body 1 into a relatively independent left chamber and a right chamber. The pilot valve sleeve 4 and the pilot valve core 5 are arranged in the left chamber, and the main valve core 2 and the return valve core 3 are arranged in the right chamber. The right end of the pilot valve sleeve 4 has a connecting rod, which slides through the shoulder and is connected to the return valve core 3 located in the right chamber.

[0092] like Figures 1-4 As shown, optionally, the drive unit 6 has a drive rod 61, which is connected to the pilot valve core 5. The drive unit 6 is used to drive the pilot valve core 5 to move linearly back and forth. The drive rod 61 is located at the left end of the pilot valve core 5. The drive rod 61 passes through the end cover 13 and is connected to the drive unit 6 located outside the valve body 1. The drive unit 6 drives the drive rod 61 to move back and forth in the left and right directions.

[0093] The drive unit 6 also includes other structural forms, such as a lead screw and nut structure, in which the lead screw and nut are driven by a motor to move, thereby driving the pilot valve core 5 to move linearly and reciprocally.

[0094] like Figure 4 As shown, in some embodiments, the valve body 1 is provided with a first oil port 14, a second oil port 15 and a third oil port 16. The first oil port 14 is connected to the second chamber 41, the second oil port 15 is connected to the third chamber 42, and the third oil port 16 is connected to the fifth chamber 51. The first oil port 14 and the second oil port 15 are used to supply oil to the second chamber 41 and the third chamber 42 respectively, and the third oil port 16 is used for oil return.

[0095] Optionally, the pilot valve sleeve 4 is equivalent to the piston moving in an independent chamber within the valve body 1. When the effective pressure-bearing areas of the second chamber 41 and the third chamber 42 are the same, and the oil supply pressures of the first oil port 14 and the second oil port 15 are the same, the pilot valve sleeve 4 can achieve balance in an independent chamber within the inner cavity and will not move. When the fifth chamber 51 is connected to one of the second chamber 41 or the third chamber 42, the working medium in the corresponding second chamber 41 or the third chamber 42 will return through the third oil port 16 to achieve pressure relief, and then the pilot valve sleeve 4 will move in an independent chamber within the inner cavity.

[0096] Furthermore, a damping screw plug 141 is provided in both the first oil port 14 and the second oil port 15. The damping screw plug 141 adjusts the pressure of the second chamber 41 and the third chamber 42 to make the pressure of the two chambers consistent, so as to prevent the pressure imbalance of the second chamber 41 and the third chamber 42 caused by machining errors.

[0097] like Figures 1-4 As shown, in some embodiments, the pilot valve sleeve 4 has a sixth chamber 43, which is connected to the third port 16 and the fifth chamber 51. During the movement of the pilot valve sleeve 4 and the pilot valve core 5, the sixth chamber 43 is always connected to the third port 16 and the fifth chamber 51, ensuring that the third port 16 and the fifth chamber 51 are always in a conductive state.

[0098] Optionally, an annular groove is provided in the middle of the outer wall of the pilot valve sleeve 4, forming a sixth cavity 43 between the annular groove and the side wall of the inner cavity of the valve body 1. A first connecting hole 44 is provided at the bottom of the annular groove, which connects the sixth cavity 43 and the fifth cavity 51. The sixth cavity 43 has a certain length in the moving direction of the pilot valve sleeve 4, ensuring that the sixth cavity 43 is always connected to the third oil port 16 throughout the entire moving stroke of the pilot valve sleeve 4. At the same time, the fifth cavity 51 has a certain length in the moving direction of the pilot valve core 5, ensuring that the first connecting hole 44 and the fifth cavity 51 are always connected throughout the entire moving stroke of the pilot valve core 5.

[0099] Furthermore, in order to achieve the connection between the second cavity 41 and the fifth cavity 51, and the connection between the third cavity 42 and the fifth cavity 51, a second connecting hole 45 and a third connecting hole 46 are provided on the pilot valve sleeve 4. The second connecting hole 45 connects the second cavity 41 and the fourth cavity, and the third connecting hole 46 connects the third cavity 42 and the fourth cavity. As the pilot valve core 5 moves back and forth in the fourth cavity, the connection or disconnection between the second cavity 41 and the fifth cavity 51, as well as the connection or disconnection between the third cavity 42 and the fifth cavity 51, can be achieved.

[0100] In some embodiments, the control valve further includes a first spring 52, which is disposed between the pilot valve core 5 and the pilot valve sleeve 4, for driving the pilot valve core 5 to reset. When the system is powered off, the pilot valve core 5 moves under the elastic force of the first spring 52, thereby resetting the pilot valve core 5 and the pilot valve sleeve 4 to their initial relative positions. The effect achieved by the first spring 52 is at least partially the same as the effect achieved by the reset component in the above embodiments, which can be the first spring 52.

[0101] like Figures 1-4As shown, in some embodiments, the main valve core 2 includes a valve stem 21 and a first ring body 22. The valve stem 21 has a hollow structure. The inlet port 24 is located on the side wall of the valve stem 21, and the return port 25 is located at one end of the valve stem 21 (the left end of the valve stem 21 shown in the figure). The working oil port of the main valve core is located at the other end of the valve stem (the right end of the valve stem 21 shown in the figure). The first ring body 22 is located on the outer wall of the valve stem 21. The valve body 1 is provided with a fourth oil port 17 and a fifth oil port 18. The fourth oil port 17 is used to supply oil to the inlet port 24, and the fifth oil port 18 is used for the return of oil to the return port 25. A first sealing gasket 23 is provided in the inner cavity. A second spring 26 is provided between the first ring body 22 and the valve body 1. The second spring 26 is used to drive the first ring body 22 to abut against the first sealing gasket 23 to block the fourth oil port 17 and the inlet port 24.

[0102] In the initial state, the main valve core 2 has the return valve core 3 separated from the valve stem 21, and the second spring 26 can drive the first ring 22 on the valve stem 21 to abut against the first sealing gasket 23, and the inlet 24 is in the closed state.

[0103] Optionally, a positioning ring 27 is provided on the inner wall surface of the inner cavity of the valve body 1, and the valve stem 21 is sleeved in the positioning ring 27. A liquid inlet chamber 19 is provided between the outer wall surface of the valve stem 21 and the inner wall surface of the inner cavity of the valve body 1. The first ring 22 and the first sealing gasket 23 are located in the liquid inlet chamber 19. The fourth oil port 17 and the liquid inlet 24 are connected through the liquid inlet chamber 19. When the first ring 22 and the first sealing gasket 23 abut, the fourth oil port 17 is connected to the liquid inlet chamber 19 on the side of the first ring 22 away from the liquid inlet 24. In the axial direction of the valve stem 21, the positioning ring 27 is correspondingly provided with the liquid inlet 24.

[0104] In other words, an inlet chamber 19 is formed between the outer wall of the valve stem 21 and the inner wall of the valve body 1. The first ring 22 and the first sealing gasket 23 are located in the inlet chamber 19. When the first ring 22 and the first sealing gasket 23 are separated, the working medium of the fourth oil port 17 enters the cavity of the valve stem 21 through the inlet port 24 after passing through the inlet chamber 19, thereby realizing oil supply. The positioning ring 27 can support and guide the valve stem 21 on the one hand, and can also block the inlet port 24 by setting the relative position of the positioning ring 27 and the inlet port 24 on the other hand.

[0105] When the first ring 22 and the first sealing gasket 23 come into contact, the liquid inlet chamber 19 is divided into a non-connected left liquid inlet chamber 19 and a right liquid inlet chamber 19. The fourth oil port 17 is connected to the right liquid inlet chamber 19. The liquid inlet 24 and the positioning ring 27 are arranged opposite to each other in the axial direction. The positioning ring 27 can block the liquid inlet 24. When the first ring 22 and the first sealing gasket 23 separate, the liquid inlet 24 and the positioning ring 27 are misaligned in the axial direction. The fourth oil port 17 and the liquid inlet 24 are both connected to the liquid inlet chamber 19 to realize oil supply.

[0106] like Figures 1-4 As shown, in some embodiments, the first ring body 22 is provided with a first chamfer 221, and the first sealing gasket 23 is provided with a second chamfer 231. The first ring body 22 and the first sealing gasket 23 are sealed by the first chamfer 221 and the second chamfer 231. By setting the chamfer, the flow rate change curve of the liquid inlet 24 is further optimized, so that the flow rate of the liquid inlet 24 can change linearly.

[0107] In some embodiments, the return valve core 3 is provided with a second sealing gasket 31 and a connector 32. The end of the valve stem 21 abuts against the second sealing gasket 31 to block the return port 25. The connector 32 is provided with a third chamfer 321. The third chamfer 321 and the end of the valve stem 21 are arranged opposite to each other. The third chamfer 321 and the valve stem 21 open and close relative to each other to adjust the opening degree of the return port 25.

[0108] Furthermore, a fourth chamfer can be provided at the end of the valve stem 21. The third chamfer 321 and the fourth chamfer are set opposite to each other, and the opening and closing action of the third chamfer 321 and the fourth chamfer is used to adjust the opening degree of the return port 25.

[0109] In other words, when the return valve core 3 abuts against the end of the valve stem 21, the end of the valve stem 21 is sealed by the second sealing gasket 31, which is to block the return port 25. When the return valve core 3 and the valve stem 21 are separated, the opening of the return port 25 can be adjusted by using the third chamfer 321 and the fourth chamfer, and the return flow rate can be linearly adjusted.

[0110] In this embodiment of the invention, the second sealing gasket 31 is fixed to the return valve core 3 by the connector 32. The flow channel 33 can be directly opened on the return valve core 3 or indirectly arranged in the middle of the return valve core 3. For example, the flow channel 33 shown in the figure is opened on the connector 32 and the pilot valve sleeve 4 to realize the communication between the first chamber 34 and the working medium chamber of the valve stem 21.

[0111] Furthermore, after the system is powered off, the first spring 52 and the second spring 26 control the valve core to reset, enabling liquid return.

[0112] like Figure 5 and Figure 6 As shown, the hydraulic cylinder control system of this embodiment includes a hydraulic cylinder 71, a first valve 72 and a second valve 73, a detection unit and a control unit. The hydraulic cylinder 71 is connected to a first oil circuit and a second oil circuit. The first valve 72 and the second valve 73 are both control valves in the above embodiment, with one of the first valve 72 and the other located in the second oil circuit. The detection unit is used to monitor the position of the hydraulic cylinder 71. The control unit is used to receive the monitoring data from the detection unit and control the operation of the first valve 72 and the second valve 73.

[0113] The detection unit is a displacement detection unit, such as a displacement sensor, and the control unit is a controller used to convert displacement commands into equivalent pulse signals and send them to the linear motors of the first valve 72 and the second valve 73. Figure 6 As shown, in some embodiments, the hydraulic cylinder 71 control system includes the following steps during use:

[0114] Obtain the target change of hydraulic cylinder 71;

[0115] Read the current position value of hydraulic cylinder 71, calculate and give the corresponding action signal;

[0116] The first valve 72 and the second valve 73 operate according to the action signal to control the extension and retraction of the hydraulic cylinder 71;

[0117] Calculate whether the position deviation of hydraulic cylinder 71 is greater than the first threshold e. If not, end the action.

[0118] If so, repeat the above steps.

[0119] like Figure 6 As shown, in some embodiments, during use, the hydraulic cylinder 71 control system further includes the following steps: detecting whether the pressure and position information of the hydraulic cylinder 71 are normal; if so, executing the action of the hydraulic cylinder 71 control system; if not, stopping the action and issuing an alarm.

[0120] like Figure 6 As shown, in some embodiments, the hydraulic cylinder 71 control system further includes an emergency power supply 74, which is used to supply power in the event of a power outage. In use, the hydraulic cylinder 71 control system further includes the following steps: detecting whether there is a power outage; if so, starting the emergency power supply 74; if not, executing the action of the hydraulic cylinder 71 control system.

[0121] like Figures 1-5 As shown in the accompanying drawings, a control valve according to a specific embodiment of the present invention will be described below.

[0122] A linear motor (i.e., drive unit 6, which can be a digital motor) is used to push the pilot valve core 5 to the right. At this time, the high-pressure liquid in the right control chamber (third chamber 42) of the pilot valve is connected to the return liquid T port. The pressure in the right control chamber of the pilot valve sleeve 4 decreases while the pressure in the left control chamber (second chamber 41) remains unchanged. The pilot valve sleeve 4 is driven by the left side, which simultaneously drives the return liquid valve core 3 to move to the right until the pressure relief hole (third connecting hole 46) of the right control chamber of the pilot valve sleeve 4 is sealed again by the Glyd ring 53 on the pilot valve core 5. At this time, the return liquid valve core 3 stops moving to the right, completing one follow-up movement.

[0123] As the pilot valve core 5 moves continuously to the right, the opening of the return port 25, located between the return valve core 3 and the main valve core 2, which enables the A-T connection, continuously decreases until the return port 25 closes. As the pilot valve core 5 continues to move to the right, the return valve core 3 pushes the main valve core 2 to the right, causing the separation degree between the first ring 22 and the first sealing gasket 23 on the main valve core 2 to continuously increase. This continuously reduces the flow resistance between PA and the flow capacity until the opening reaches its maximum. Thus, linear regulation of the AT return flow rate and the PA inlet flow rate is achieved. When the pilot valve core 5 moves in the opposite direction, due to its follow-up characteristics, the inlet port 24 gradually closes, and the return port 25 gradually opens.

[0124] The pilot valve core 5 is driven by a linear motor and can stop at any position during its stroke. Due to its follow-up characteristics, the pilot valve sleeve 4, return valve core 3, and main valve core 2 stop accordingly. The inlet port 24 and return port 25 can be adjusted to any degree, thereby achieving the purpose of linear flow regulation.

[0125] The pilot valve sleeve has flow channels 33 drilled for force balance. The annular cavity areas S1-S2 and S3 of the return valve core are equal. This design ensures that when the second sealing gasket of the return valve core just contacts the valve stem of the main valve core:

[0126] The right side of the main valve stem is subjected to a hydraulic thrust F1 = P A *S3;

[0127] The left side of the main valve stem is subjected to a hydraulic balancing force F2 = P A *(S1-S2);

[0128] When the two are equal, F1 = F2, the movement of the main valve core is only affected by friction, thus improving the response speed of the main valve core.

[0129] Function of pilot valve core 5: The pilot valve core 5 relies on its own equipped Glyd ring 53 to seal the pressure control holes (i.e., the second connecting hole 45 and the third connecting hole 46) of the pilot valve sleeve 4. Due to the small size structure of the pilot valve core 5 and the low friction between it and the pilot valve sleeve 4, the position of the pilot valve sleeve 4 remains unchanged at the moment the linear motor pushes the pilot valve core 5 to move. When one of the left control chamber and the right control chamber is connected to the return liquid T, the forces on both sides of the pilot valve sleeve 4 are unbalanced, and the pilot valve sleeve 4 moves with the pilot valve core 5. The response time of the pilot valve sleeve 4 and the pilot valve core 5 following the movement is very short.

[0130] Linear motor: Drives the pilot valve core 5 to perform translational extension and retraction. The extension and retraction displacement accuracy can reach 0.01mm. Therefore, the extension and retraction displacement of the pilot valve core 5 and the extension and retraction displacement of the main valve stem 21 can achieve an extension and retraction of 0.01mm. The motor pushes the pilot valve core 5. Since the pilot valve core 5 has low friction, it can be pushed with less force. When the main valve core 2 returns to the liquid port 25 or the liquid inlet 24 to maintain the opening, due to the design of the force-balanced flow channel 33, only a small holding force is required from the motor.

[0131] After the system is powered off, the nut of the rotatable linear motor replaces the motor thrust and controls the pilot valve core 5 to reciprocate.

[0132] Return valve core 3: The return valve core 3 is installed on the pilot valve sleeve 4 by means of a threaded connection. The second sealing gasket 31 is fixed on the return valve core 3 by means of a screw. The return port 25 is closed by means of the hydraulic thrust F1 on the right side of the valve stem 21 of the main valve core 2 and the hydraulic balancing force F2 on the left side of the return valve core 3, which presses the valve stem 21 on the second sealing gasket to achieve the sealing of the return port 25. The opening degree of the return port 25 is adjusted by means of the chamfer at the end of the screw, which further improves the linear adjustment of the return flow rate and the position of the return valve core 3.

[0133] After the system is powered off, the first spring 52 and the second spring 26 control the valve core to reset, allowing liquid to return from port A and port T.

[0134] Main valve core 2: such as Figure 5 As shown, the system relies on the second spring 26 for reset. In the initial state, the high-pressure liquid at port P presses the main valve stem 21 and the first sealing gasket 23 together to achieve PA sealing. That is, the high-pressure liquid at port P acts on the first ring 22 to press the first ring 22 and the first sealing gasket 23 together. During the process of the pilot valve sleeve 4 moving to the right, the pilot valve sleeve 4 drives the return valve core 3 to push the main valve core 2 to open slowly, thereby achieving soft start and precise adjustment of the opening degree, and realizing linear control of the flow rate.

[0135] like Figure 5 As shown: The principle of the control valve in this embodiment of the invention relies on a motor to adjust the opening degree of PA and AT and switch the working position.

[0136] The control system of the hydraulic cylinder 71 according to a specific embodiment of the present invention is described below with reference to the accompanying drawings.

[0137] like Figure 6 and Figure 7As shown, the displacement detection unit monitors the position of the hydraulic cylinder 71 in real time. When the position change signal is input to the controller, the controller converts the displacement command into an equivalent pulse signal and sends it to the drive motor of the follower pilot proportional directional valve (first valve 72 and second valve 73) (i.e., the drive unit 6 of the first valve 72 and second valve 73). Under the control of the motor, the two follower pilot proportional directional valves change their opening to control the extension and retraction of the hydraulic cylinder 71. As the hydraulic cylinder 71 gradually approaches the target control value, the opening of the two follower pilot proportional directional valves continuously decreases. When the position of the hydraulic cylinder 71 changes to within the specified position error range, the follower pilot proportional directional valves reset, the hydraulic cylinder 71 stops moving, and the hydraulic cylinder 71 is locked by the hydraulic control check lock, thus completing one control cycle.

[0138] Emergency power supply 74 is used to supply power to the control system of hydraulic cylinder 71 in the event of a sudden power outage.

[0139] In addition, for the power failure protection function, the present invention proposes two solutions: equipping an emergency power supply 74 and adding a pilot valve core reset spring (i.e., the first spring 52).

[0140] The emergency power supply solution 74 features a self-locking motor with relatively low drive power, making it suitable for coal mine applications.

[0141] To address the power outage scenarios in coal mine applications, this embodiment of the invention utilizes an emergency power supply 74 to reset the pilot valve core 5 under emergency power conditions. In this case, the first spring 52 is unnecessary, resulting in lower pilot drive power due to the absence of its resistance. Furthermore, the emergency power supply 74 can power not only a single unit but also multiple units simultaneously, making the control of the servo-operated proportional directional valve more flexible.

[0142] The beneficial effects achieved by the embodiments of the present invention are as follows:

[0143] Compared to electro-hydraulic proportional valves in related technologies that use proportional electromagnets for driving, the proportional electromagnets generate significant heat during the holding phase and have a short control stroke and small control flow rate. In contrast, this invention uses a linear motor or DC servo motor with a lead screw and nut mechanism. The holding phase is completed by the motor's self-locking or the lead screw and nut mechanism's self-locking, eliminating the need for motor power supply. This phase saves more than 50% of energy. Furthermore, the embodiments of this invention constitute a position follow-up system, ensuring that the control stroke is unaffected and allowing for a wide control flow rate range.

[0144] This invention employs a pilot-operated position servo principle to develop a low-power drive proportional control two-position three-way proportional valve or digital valve, enabling precise adjustment of the liquid supply valve core opening and the liquid return valve core opening with a single external control quantity, thereby reducing the control difficulty and cost of the system.

[0145] The pressure balancing structure of the main valve core during the opening process of the liquid supply valve core in this embodiment of the invention reduces the hydraulic imbalance force of the valve core and improves the stability of the system.

[0146] The embodiments of the present invention have a power failure protection function, which can achieve power failure protection through two schemes: emergency power supply and adding a pilot valve core reset spring (first spring).

[0147] The control valve in this invention embodiment can be used as a water-based control valve to achieve precise control of large flow rate under high water-based and high-pressure conditions, reduce the machining and fitting accuracy of parts, reduce machining difficulty, reduce the hydraulic shock to the system at the moment of opening and closing, improve the life of each component in the hydraulic system, and achieve stepless and precise adjustment of water hydraulic pressure.

[0148] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0149] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0150] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0151] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0152] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0153] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A control valve, characterized in that, include: Valve body, the valve body having an internal cavity; A main valve core and a return valve core are provided in the inner cavity. The return valve core is movable in the inner cavity and has a first displacement state and a second displacement state. In the first displacement state, the return valve core is separated from the main valve core and moves relative to the main valve core to adjust the opening of the return port of the main valve core. In the second displacement state, the return valve core abuts against the main valve core and moves synchronously with the main valve core to adjust the opening of the inlet port of the main valve core. A pilot valve assembly is disposed in the inner cavity and is connected to the return valve core; A drive unit is connected to the pilot valve assembly to drive the pilot valve assembly to move within the inner cavity of the valve body and cause the return valve core to move accordingly. The return valve core has a first cavity between the end away from the main valve core and the valve body. The return valve core has a flow channel inside, which is used to connect the first cavity and the working medium chamber of the main valve core to balance the hydraulic pressure at both ends of the return valve core in the direction of movement. Wherein: the pilot valve assembly includes: A pilot valve sleeve is disposed in the inner cavity and is movable in the inner cavity. The pilot valve sleeve is connected to the return valve core. A second cavity and a third cavity are provided between the pilot valve sleeve and the valve body. The second cavity and the third cavity have a pressure difference to drive the pilot valve sleeve to move in the inner cavity. The pilot valve sleeve has a fourth cavity. A pilot valve core is disposed in the fourth cavity, and a fifth cavity is provided between the pilot valve core and the side wall of the fourth cavity. The pilot valve core is movable in the fourth cavity so that the fifth cavity communicates with one of the second cavity and the third cavity. The fifth cavity is used to depressurize the second cavity or the third cavity to adjust the pressure difference between the second cavity and the third cavity. The drive unit is used to drive the pilot valve core to move in the fourth chamber.

2. The control valve according to claim 1, characterized in that, The pressure-bearing area on the side of the return valve core away from the main valve core is equal to the cross-sectional area of ​​the working port end of the main valve core; and / or The drive unit includes a digital motor, which receives a displacement command equivalent signal from the control unit to control the operation of the pilot valve assembly; and / or The control valve further includes a reset component, which is disposed on the pilot valve assembly and is used to reset the pilot valve assembly; the control valve also includes an emergency power supply, which is connected to the drive unit.

3. The control valve according to claim 1, characterized in that, The valve body is provided with a first oil port, a second oil port and a third oil port. The first oil port is connected to the second cavity, the second oil port is connected to the third cavity, and the third oil port is connected to the fifth cavity. The first oil port and the second oil port are used to supply oil to the second cavity and the third cavity respectively, and the third oil port is used to return oil.

4. The control valve according to claim 3, characterized in that, The main valve core, the return valve core, the pilot valve sleeve, and the pilot valve core are coaxially arranged and all move along the axial direction; the valve body includes a first valve body and a second valve body, one end of the first valve body is provided with an end cap, and the second valve body is provided at the other end of the first valve body; and / or The driving unit has a driving rod connected to the pilot valve core, and the driving unit is used to drive the pilot valve core to move linearly reciprocally; it also includes a first spring disposed between the pilot valve core and the pilot valve sleeve, used to drive the pilot valve core to reset; damping screw plugs are provided in both the first and second oil ports; and / or The pilot valve sleeve has a sixth chamber, which is connected to the third oil port and the fifth chamber. During the movement of the pilot valve core and the pilot valve sleeve, the fifth chamber, the sixth chamber and the third oil port are always connected.

5. The control valve according to any one of claims 1-4, characterized in that, The main valve core includes: The valve stem has the working medium chamber, the inlet is located on the side wall of the valve stem, the return port is located at one end of the valve stem, and the working oil port of the main valve core is located at the other end of the valve stem. A first ring body is disposed on the outer wall of the valve stem. The valve body is provided with a fourth oil port and a fifth oil port. The fourth oil port is used to supply oil to the inlet port, and the fifth oil port is used to return oil to the return port. A first sealing gasket is provided in the inner cavity. A second spring is provided between the first ring body and the valve body. The second spring is used to drive the first ring body to abut against the first sealing gasket to block the fourth oil port and the inlet port.

6. The control valve according to claim 5, characterized in that, The first ring body has a first chamfer, and the first sealing gasket has a second chamfer. The first ring body and the first sealing gasket are sealed by abutting against each other through the first chamfer and the second chamfer; and / or It also includes a positioning ring disposed in the inner cavity, the valve stem being slidably sleeved in the positioning ring, and a liquid inlet cavity being formed between the outer wall surface of the valve stem and the inner wall surface of the inner cavity of the valve body. The first ring and the first sealing gasket are located in the liquid inlet cavity, and the fourth oil port and the liquid inlet are connected through the liquid inlet cavity. When the first ring and the first sealing gasket abut against each other, the fourth oil port is connected to the liquid inlet cavity on the side of the first ring away from the liquid inlet, and the positioning ring is correspondingly arranged to the liquid inlet in the axial direction of the valve stem; and / or The return valve core is provided with a second sealing gasket and a connector. In the second displacement state, the end of the valve stem abuts against the second sealing gasket to block the return port. The connector is provided with a third chamfer. The third chamfer and the end of the valve stem are arranged opposite to each other. In the first displacement state, the third chamfer and the valve stem open and close relative to each other to adjust the opening degree of the return port.

7. A hydraulic cylinder control system, characterized in that, include: A hydraulic cylinder, wherein the hydraulic cylinder is connected to a first oil circuit and a second oil circuit; The first valve and the second valve are both control valves according to any one of claims 1-6, wherein one of the first valve and the second valve is provided in the first oil circuit and the other is provided in the second oil circuit; A detection unit is used to monitor the position of the hydraulic cylinder; The control unit is used to receive monitoring data from the detection unit and control the operation of the first valve and the second valve.

8. The hydraulic cylinder control system according to claim 7, characterized in that, In use, the hydraulic cylinder control system includes the following steps: Obtain the target change of the hydraulic cylinder; Read the current position value of the hydraulic cylinder, calculate and give the corresponding action signal; The first valve and the second valve operate according to the action signal to control the extension and retraction of the hydraulic cylinder; Calculate whether the position deviation of the hydraulic cylinder is greater than the first threshold. If not, end the action. If so, repeat the above steps.

9. The hydraulic cylinder control system according to claim 8, characterized in that, During use, the hydraulic cylinder control system also The steps include: checking whether the hydraulic cylinder pressure and position information are normal; if so, executing the action of the hydraulic cylinder control system; if not, stopping the action and issuing an alarm; and / or The hydraulic cylinder control system also includes an emergency power supply, which is used to supply power in the event of a power outage. In use, the hydraulic cylinder control system further includes the following steps: detecting whether there is a power outage; if so, activating the emergency power supply; if not, executing the actions of the hydraulic cylinder control system.

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