Plug-in valve, hydraulic control system and control method

Abstract

This invention discloses a cartridge valve, a hydraulic system, and a control method. The cartridge valve includes a valve body, a valve cover at one end of the valve body, and a valve cup and a valve core disposed within the valve body. The valve body includes a first oil circuit connection port and a second oil circuit connection port. The first oil circuit connection port is connected to external pressure oil, and the second oil circuit connection port is connected to an actuator. The valve core is used to control the on / off state and flow rate between the first and second oil circuit connection ports. The valve cover has a first control chamber, and a limiting rod is provided between the valve cover and the valve core. The first control chamber is used to control the position of the limiting rod. The valve cup has a second control chamber, which is used to control the position of the valve core. The end of the limiting rod can abut against the valve core to limit the displacement of the valve core. The hydraulic system includes the cartridge valve described above. The control method uses the cartridge valve described above for adjustment. Using this invention, three operating conditions—oil circuit cutoff, large and small flow rates—can be controlled through a single valve body, simplifying oil circuit design and reducing production costs.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology, and in particular to a cartridge valve, a hydraulic control system, and a control method. Background Technology

[0002] In hydraulic transmission systems, actuators often need to achieve multiple operating conditions such as rapid advance and working advance. Rapid advance requires a large flow rate of hydraulic oil to improve efficiency, while working advance requires a small flow rate for precise control. Therefore, multi-level control of oil flow is one of the core requirements of hydraulic system design, and its control scheme directly affects the system's structural complexity and operating costs. Current technologies often employ a combination of dual cartridge valves or proportional valves with auxiliary components to achieve flow control. The dual cartridge valve scheme uses two independent cartridge valves to handle oil circuit on / off and flow regulation functions respectively, with pilot valves controlling the movement of their respective valve cores. The flow rate switching is achieved by changing the valve core opening. The clearance between the valve core and the valve sleeve, as well as the spring preload, determines the flow control accuracy. The proportional valve scheme uses electrical signals to adjust the valve core displacement, achieving stepless flow regulation by changing the throttle orifice size. It typically requires a pressure compensator to stabilize the flow output, and in some scenarios, a check valve is also needed in series to optimize oil circuit direction control. However, the dual cartridge valve solution requires the design of two independent oil circuit channels within the hydraulic system, resulting in a complex oil circuit layout. Furthermore, the size of the hydraulic system increases significantly, occupying more installation space and raising material costs. On the other hand, the proportional valve itself has a high manufacturing cost and requires strict cleanliness of the hydraulic oil, necessitating the additional configuration of a high-precision oil filter, which also increases the system setup cost and maintenance burden. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a cartridge valve that can achieve three working conditions of oil circuit cut-off, large and small flow rate control through a single valve body, thereby simplifying oil circuit design and reducing production costs. To solve the above-mentioned technical problems, the present invention provides a cartridge valve, including a valve body, a valve cover disposed at one end of the valve body, and a valve cup and a valve core disposed within the valve body. The valve body includes a first oil passage connection port and a second oil passage connection port. The first oil passage connection port is connected to external pressure oil, and the second oil passage connection port is connected to an actuator. The valve core is used to control the on / off state and flow rate between the first oil passage connection port and the second oil passage connection port.

[0004] The valve cover is provided with a first control chamber, and a limiting rod is provided between the valve cover and the valve core. The first control chamber is used to control the position of the limiting rod.

[0005] The valve cup is provided with a second control chamber, which is located between the valve cover and the valve core. The second control chamber is used to control the position of the valve core.

[0006] The end of the limiting rod can abut against the valve core to limit the displacement of the valve core.

[0007] As an improvement to the above solution, the valve cover is provided with a first groove, the limiting rod includes a control end, the control end is movably disposed in the first groove, the cartridge valve also includes a pressure cap, the pressure cap is used to cover the first groove and form a sealed cavity, the control end and one side inner wall of the pressure cap form the first control cavity, and the control end and the bottom of the first groove form a breathing cavity.

[0008] The limiting rod also includes a limiting section extending from the control end toward the valve core. The valve core has a second groove with its opening facing the valve cover. The end of the limiting section is a limiting end that can be inserted into the second groove and abut against the bottom of the second groove.

[0009] As an improvement to the above solution, the valve cup is provided with a movable hole, the valve core is disposed in the movable hole and can move within the movable hole, and the end of the valve core near the valve cover forms a second control cavity with the valve cover.

[0010] The valve cup has a side hole on its side and an end hole at its end. The first oil passage is connected to the side hole, and the second oil passage is connected to the end hole. When the valve core moves toward the valve cover, the side hole, the end hole, and the movable hole are connected to each other. When the valve core moves away from the valve cover, the valve core blocks the connection between the side hole, the end hole, and the movable hole.

[0011] As an improvement to the above solution, the cartridge valve further includes an elastic element disposed in the second groove, one end of the elastic element abutting against the bottom of the second groove, and the other end of the elastic element abutting against the valve cover.

[0012] As an improvement to the above solution, the cartridge valve further includes an adjusting rod and a locking nut. One end of the adjusting rod passes through the pressure cap and enters the first groove, abutting against the control end. The locking nut is sleeved on the other end of the adjusting rod and abuts against the wall of the pressure cap. The adjusting rod is used to control the movement stroke of the limiting rod.

[0013] The present invention also provides a hydraulic system including a cartridge valve as described above, and further including a first control valve and a second control valve, wherein the first control valve is used to control the first control chamber, and the second control valve is used to control the second control chamber.

[0014] The first control valve includes a first communication passage. When the first control valve is in a first state, the inlet end of the first communication passage is connected to an external control oil circuit, and the outlet end of the first communication passage is connected to the first control chamber through a first oil circuit.

[0015] The second control valve includes a second communication passage. When the second control valve is in the first state, the inlet end of the second communication passage is connected to an external control oil circuit, and the outlet end of the second communication passage is connected to the second control chamber through a second oil circuit.

[0016] As an improvement to the above solution, the first control valve further includes a third connecting passage. When the first control valve is in the second state, the inlet end of the third connecting passage is connected to the first control chamber, and the outlet end of the third connecting passage is connected to the external oil tank.

[0017] The second control valve also includes a fourth communication passage. When the second control valve is in the second state, the inlet end of the fourth communication passage is connected to the second control chamber, and the outlet end of the fourth communication passage is connected to the external oil tank.

[0018] The present invention also provides a control method for controlling the cartridge valve as described above, comprising the following steps: When it is necessary to close the cartridge valve, switch the second control valve to the first state so that the valve core blocks the connection between the first oil circuit port and the second oil circuit port; When it is required to run at the first preset flow rate, the first control valve is switched to the first state and the second control valve is switched to the second state, the first oil circuit connection port and the second oil circuit connection port are connected and the hydraulic oil flow rate is the first preset flow rate; When it is required to run at the second preset flow rate, the first control valve is switched to the second state, and the second control valve is switched to the second state. The first oil circuit connection port and the second oil circuit connection port are connected and the hydraulic oil flow rate is the second preset flow rate. The first preset flow rate is not greater than the second preset flow rate.

[0019] As an improvement to the above solution, the control method further includes the following steps: When the cartridge valve needs to be closed, the second control valve is switched to the first state. At this time, the second communication passage of the second control valve is connected between the second control chamber and the external control oil circuit. The elastic element acts on the second groove to block the communication between the valve core, the end hole and the movable hole of the valve cup. At this time, the distance between the first end face of the valve core and the valve cover wall is H, the distance between the end face of the limit end and the bottom groove of the second groove is H1, and the distance between the end face of the control end and the gland is H2. When the first preset flow rate is required, the first control valve is switched to the first state, and the second control valve is switched to the second state. At this time, the first connecting passage of the first control valve is connected between the first control chamber and the external control oil circuit, and the fourth connecting passage of the second control valve is connected between the second control chamber and the external oil tank. The end face of the limiting end abuts against the bottom groove of the second groove. At this time, the distance between the first end face of the valve core and the valve cover wall is B1, the distance between the second end face of the valve core and the end hole opening of the valve cup is B2, the distance between the end face of the limiting end and the bottom groove of the second groove is B3, and the distance between the end face of the control end and the gland is B4; where B1=H-H1, B2=H1, B3=0, and B4=H2. When the second preset flow rate is required, the first control valve is switched to the second state, and the second control valve is switched to the second state. At this time, the third connection passage of the first control valve is connected between the first control chamber and the external oil tank, and the fourth connection passage of the second control valve is connected between the second control chamber and the external oil tank. The end face of the limiting end abuts against the bottom groove of the second groove and the limiting rod moves away from the valve cup. At this time, the distance between the first end face of the valve core and the valve cover wall is C1, the distance between the second end face of the valve core and the end hole opening of the valve cup is C2, the distance between the end face of the limiting end and the bottom groove of the second groove is C3, and the distance between the end face of the control end and the pressure cap is C4; where C1=0, C2=H, C3=0, C4=H2-(H-H1).

[0020] As an improvement to the above solution, the control method further includes the following steps: When it is necessary to increase the second preset flow rate, rotate the adjusting rod so that the end of the adjusting rod closer to the control end is away from the bottom of the first tank. When it is necessary to reduce the second preset flow rate, rotate the adjusting rod so that the end of the adjusting rod closer to the control end is close to the bottom of the first tank.

[0021] Implementing this invention has the following beneficial effects: The cartridge valve of the present invention comprises a valve body, a valve cover at one end of the valve body, and a valve cup and a valve core disposed within the valve body. The valve body includes a first oil passage connection port and a second oil passage connection port corresponding to external pressure oil and an actuator. The valve cover contains a first control chamber, and the valve cup contains a second control chamber. The valve core is used to control the on / off state and flow rate between the first oil passage connection port and the second oil passage connection port. By controlling the second control chamber, the position of the valve core can be controlled. When the valve core is located between the first oil passage connection port and the second oil passage connection port, it can control the first oil passage... The passage between the connecting port and the second oil circuit connecting port is closed, thereby achieving the oil circuit cutoff function. By controlling the valve core to move away from both the first and second oil circuit connecting ports, workpiece control under low flow conditions can be achieved. Since the end of the limiting rod can abut against the valve core, limiting its displacement, when the limiting rod is controlled by the first control chamber, the limiting rod allows the valve core to move further, increasing the diameter of the passage between the first and second oil circuit connecting ports, thus enabling workpiece control under high flow conditions. Therefore, this invention can achieve oil circuit cutoff, high and low flow rate control with a single valve body, simplifying oil circuit design and reducing production costs. Attached Figure Description

[0022] Figure 1 This is a cross-sectional structural diagram of the cartridge valve of the present invention in the closed state; Figure 2 This is a cross-sectional structural diagram of the valve cup, valve core, valve cover, and pressure cap of the present invention; Figure 3 This is a cross-sectional structural diagram of the cartridge valve of the present invention under low flow conditions; Figure 4 This is a cross-sectional structural diagram of the cartridge valve of the present invention under high flow conditions; Figure 5 This is a cross-sectional structural diagram of the cartridge valve of the present invention with an adjusting rod and a locking nut; Figure 6 This is a schematic diagram of the cartridge valve of the hydraulic system of the present invention in the closed state; Figure 7 This is a schematic diagram of the cartridge valve of the hydraulic system of the present invention under low flow conditions; Figure 8 This is a schematic diagram of the cartridge valve of the hydraulic system of the present invention under high flow conditions; Figure 9 This is a flowchart illustrating the control method of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. It is hereby declared that the directional terms such as up, down, left, right, front, back, inside, and outside used in this text are based solely on the accompanying drawings and are not intended to specifically limit the invention.

[0024] See Figure 1 and Figure 2 This invention discloses a cartridge valve 10, including a valve body 1, a valve cover 2 disposed at one end of the valve body 1, and a valve cup 3 and a valve core 4 disposed within the valve body 1. The valve body 1 includes a first oil passage connection port 11 and a second oil passage connection port 12. The first oil passage connection port 11 is connected to external pressure oil, and the second oil passage connection port 12 is connected to an actuator. The valve core 4 is used to control the on / off state and flow rate between the first oil passage connection port 11 and the second oil passage connection port 12. The valve core 4 controls the on / off state and flow rate by changing its own position.

[0025] The valve cup 3 is provided with a second control chamber 31, which is located between the valve cover 2 and the valve core 4. The second control chamber 31 is used to control the position of the valve core 4, specifically whether the valve core 4 blocks the first oil passage connection 11 and the second oil passage connection 12. When sufficient control pressure is applied to the second control chamber 31, the valve core 4 can move along the inner cavity of the valve cup 3 and fit into the passage, completely blocking the passage between the first oil passage connection 11 and the second oil passage connection 12, blocking the delivery of external pressure oil to the actuator, realizing the oil passage cut-off function, and meeting the system shutdown or pressure holding requirements. When the pressure in the second control chamber 31 decreases, the oil passage pressure is greater than the control pressure of the second control chamber 31 (and the elastic force generated by the elastic element 7), and the valve core 4 can break through the control of the second control chamber 31, thereby leaving the position between the first oil passage connection 11 and the second oil passage connection 12 and moving away from the passage. At this time, a narrow gap is formed between the valve core 4 and the passage. External pressure oil can only flow through this gap to the second oil circuit connection port 12, which can realize the control of the workpiece under low flow conditions and adapt to the working scenario with low flow requirements, such as feed.

[0026] The valve cover 2 is provided with a first control chamber 21, and a limiting rod 5 is provided between the valve cover 2 and the valve core 4. The first control chamber 21 is used to control the position of the limiting rod 5. The end of the limiting rod 5 can abut against the valve core 4 to limit the displacement of the valve core 4. Without additional control, the limiting rod 5 limits the movement distance of the valve core 4 to prevent the valve core 4 from moving excessively. When it is necessary to switch to a high flow rate condition, the first control chamber 21 controls the limiting rod 5 to move it away from the valve core 4, thereby releasing the displacement restriction on the valve core 4 and allowing the valve core 4 to move further away from the passage. This further increases the diameter of the passage between the first oil passage connection port 11 and the second oil passage connection port 12, allowing external pressure oil to be delivered to the actuator more smoothly through the passage. This enables the control of the workpiece under high flow rate conditions and is suitable for high-efficiency operation scenarios such as fast-forward.

[0027] The beneficial effects of the embodiments of the present invention are as follows: In this embodiment of the invention, the cartridge valve 10 includes a valve body 1, a valve cover 2 located at one end of the valve body 1, and a valve cup 3 and a valve core 4 located within the valve body 1. The valve body 1 includes a first oil passage port 11 and a second oil passage port 12 corresponding to external pressure oil and an actuator. The valve cover 2 has a first control chamber 21, and the valve cup 3 has a second control chamber 31. The valve core 4 controls the on / off state and flow rate between the first oil passage port 11 and the second oil passage port 12. By controlling the second control chamber 31, the position of the valve core 4 can be controlled. When the valve core 4 is located between the first oil passage port 11 and the second oil passage port 12, it can... Closing the passage between the first oil circuit connection port 11 and the second oil circuit connection port 12 achieves the oil circuit cutoff function. By controlling the valve core 4 away from the first oil circuit connection port 11 and the second oil circuit connection port 12, workpiece control under low flow conditions can be achieved. Since the end of the limiting rod 5 can abut against the valve core 4, limiting the displacement of the valve core 4, when the first control chamber 21 controls the limiting rod 5, the limiting rod 5 allows the valve core 4 to further increase its movement distance, further increasing the diameter of the passage between the first oil circuit connection port 11 and the second oil circuit connection port 12, thereby enabling workpiece control under high flow conditions. Compared to the existing dual-cartridge valve solution, there is no need to design two independent oil circuit channels, simplifying the oil circuit layout, reducing material consumption, and saving installation space. Compared to the proportional valve solution, there is no need to invest in expensive proportional valves and high-precision oil filters, reducing system manufacturing costs and subsequent maintenance burden. Furthermore, it does not rely on stringent hydraulic oil cleanliness conditions, making it suitable for a wider range of scenarios.

[0028] The valve cover 2 has a first groove 22 inside. The limiting rod 5 includes a control end 51, which is movably disposed within the first groove 22. The first groove 22 provides guidance and installation space for the movement of the limiting rod 5. The cartridge valve 10 also includes a pressure cap 6, which covers the first groove 22 and forms a sealed cavity. The control end 51 and one inner wall of the pressure cap 6 form the first control cavity 21. By applying pressure to the first control cavity 21, the control end 51 can be driven to move axially along the first groove 22, thereby causing the limiting rod 5 to move as a whole. The control end 51 and the bottom of the first groove 22 form a breather cavity 23, which is connected to an external oil tank. This breather cavity 23 can adapt to different oil volumes as the control end 51 moves, thus buffering and protecting the movement of the control end 51. At the same time, it makes the position adjustment of the limiting rod 5 more stable, providing stable support for flow control.

[0029] The limiting rod 5 also includes a limiting section 52, which extends from the control end 51 toward the valve core 4. The valve core 4 has a second groove 41 inside, the opening of which faces the valve cover 2. The end of the limiting section 52 is a limiting end 53, which can be inserted into the second groove 41 and abut against the bottom of the groove. When operating at low flow rate, the limiting end 53 is inserted into the second groove 41 and abuts against the bottom, restricting further movement of the valve core 4 and ensuring a stable gap between the valve core 4 and the passage, maintaining the consistency of low flow rate output. When switching to high flow rate, the first control chamber 21 drives the control end 51 to move by reducing pressure, causing the limiting section 52 to move synchronously, so that the limiting end 53 disengages from the bottom of the second groove 41 and retracts toward the first groove 22, releasing the limitation on the valve core 4 and allowing the valve core 4 to move further to expand the passage diameter.

[0030] The valve cup 3 has a movable hole, and the valve core 4 is disposed within the movable hole and can move within it. The movable hole provides precise guidance for the movement of the valve core 4, preventing radial displacement of the valve core 4 during force-driven movement, ensuring the fitting accuracy of the valve core 4 with each channel, and providing structural support for oil circuit opening / closing and flow regulation. The end of the valve core 4 closest to the valve cover 2 forms a second control chamber 31 with the valve cover 2. By applying or reducing pressure to the second control chamber 31, the valve core 4 can be driven to move axially along the movable hole, thereby controlling the oil circuit connection status.

[0031] The valve cup 3 has a side hole 32 on its side and an end hole 33 at its end. The first oil passage connection 11 communicates with the side hole 32, and the second oil passage connection 12 communicates with the end hole 33. When the valve core 4 moves towards the valve cover 2, the side hole 32, the end hole 33, and the movable hole communicate with each other. When the valve core 4 moves away from the valve cover 2, the valve core 4 blocks the communication between the side hole 32, the end hole 33, and the movable hole. External pressure oil enters the valve cup 3 from the first oil passage connection 11 through the side hole 32, and then is delivered to the actuator from the second oil passage connection 12 through the end hole 33. When the valve core 4 moves towards the valve cover 2, it no longer obstructs the side hole 32 and the end hole 33. The side hole 32 and the end hole 33 are interconnected with the movable hole, allowing oil to flow smoothly between them, thus providing a basis for flow regulation. When the valve core 4 moves away from the valve cover 2, its outer circumferential surface fits tightly against the inner wall of the movable hole, simultaneously blocking the communication channel between the side hole 32 and the end hole 33, thus cutting off the connection between them and achieving the oil circuit cutoff function.

[0032] The cartridge valve 10 also includes an elastic element 7, which is disposed within the second groove 41. One end of the elastic element 7 abuts against the bottom of the second groove 41, and the other end abuts against the valve cover 2. The elastic element 7 generates a preload force through its own elastic deformation, providing a reset support for the valve core 4. When the pressure in the second control chamber 31 decreases, and the valve core 4 breaks through the control of the second control chamber 31 and moves towards the valve cover 2, the elastic element 7 is compressed and stores elastic potential energy. When the pressure in the second control chamber 31 increases, and the valve core 4 needs to be driven to move away from the valve cover 2 to cut off the oil circuit, the elastic element 7 releases its elastic potential energy, assisting the valve core 4 to quickly reset, shortening the oil circuit cutoff response time, and reducing the pressure load on the second control chamber 31, thereby improving control efficiency. In addition, the elastic element 7 can also buffer the contact force between the valve core 4 and the valve cover 2, avoiding rigid collisions that could damage components and extending the overall service life.

[0033] To adapt to the flow requirements of different actuators, the cartridge valve 10 also includes an adjusting rod 8 and a locking nut 9. One end of the adjusting rod 8 passes through the pressure cap 6 and enters the first groove 22, abutting against the control end 51. The locking nut 9 is sleeved on the other end of the adjusting rod 8 and abuts against the wall of the pressure cap 6. The adjusting rod is used to control the movement stroke of the limiting rod 5, and the locking nut 9 is used to fix the position of the adjusting rod 8. When the adjusting rod 8 is adjusted to the target stroke, the locking nut 9 is tightened to make it fit tightly against the wall of the pressure cap 6, which can prevent the adjusting rod 8 from shifting due to vibration during operation, ensure the stability of the movement stroke of the limiting rod 5, and thus ensure the consistency of flow control. In this embodiment, through the cooperation of the adjusting rod 8 and the locking nut 9, the limiting stroke can be flexibly adjusted to adapt to different flow requirements. It can adapt to a variety of actuators without replacing parts, improving the versatility of the device.

[0034] This invention also discloses a hydraulic system, including the cartridge valve 10 as described above, and further including a first control valve 20 and a second control valve 30. The first control valve 20 controls the first control chamber 21, and the second control valve 30 controls the second control chamber 31. The first control valve 20 controls the first control chamber 21 and drives the limit rod 5 to achieve displacement adjustment or positioning by adjusting the pressure state of the first control chamber 21. The second control valve 30 controls the second control chamber 31 and drives the valve core 4 to move to switch the oil circuit connection state by changing the pressure of the second control chamber 31. The two work together to provide power support for the switching of the working conditions of the cartridge valve 10, and can achieve graded regulation without complex control modules, thereby completing the stable switching of three working conditions: oil circuit cutoff, small flow, and large flow.

[0035] The first control valve 20 includes a first connecting passage 201. When the first control valve 20 is in a first state, the inlet end of the first connecting passage 201 is connected to an external control oil circuit, and the outlet end of the first connecting passage 201 is connected to the first control chamber 21 through a first oil circuit 40. The first state can be either a de-energized state or an energized state. In this embodiment, the first state is a de-energized state. When the first control valve 20 is in a de-energized state, the pressure oil from the external control oil circuit is delivered to the first control chamber 21 through the first connecting passage 201 and the first oil circuit 40, pushing the control end 51 to move the limiting rod 5 towards the valve core 4, thereby limiting the displacement of the valve core 4 and realizing the switching of the oil circuit.

[0036] The second control valve 30 includes a second communication passage 301. When the second control valve 30 is in the first state, the inlet end of the second communication passage 301 is connected to the external control oil circuit, and the outlet end of the second communication passage 301 is connected to the second control chamber 31 through the second oil circuit 50. The first state can be either a de-energized state or an energized state. In this embodiment, the first state is a de-energized state. When the second control valve 30 is in the de-energized state, the pressure oil from the external control oil circuit enters the second control chamber 31 through the second communication passage 301 and the second oil circuit 50, applying pressure to the valve core 4 and pushing the valve core 4 to move away from the valve cover 2 until it blocks the communication between the side hole 32, the end hole 33, and the movable hole, thereby achieving the oil circuit cut-off function and meeting the requirements of system shutdown, pressure holding, and other operations.

[0037] In the initial state, the second control valve 30 is in the first state (power off state), the second control chamber 31 is supplied with pressurized oil, and the valve core 4 blocks the oil circuit to achieve the cut-off function. Regardless of the state of the first control valve 20 at this time, under the pressure of the pressurized oil in the second control chamber 31 and the elastic force of the elastic element 7, the valve core 4 is in a blocked state between the first oil circuit connection port 11 and the second oil circuit connection port 12, and the cartridge valve 10 is in a closed state at this time.

[0038] The second control valve 30 also includes a fourth connecting passage 302. When the second control valve 30 is in the second state, the inlet end of the fourth connecting passage 302 is connected to the second control chamber 31, and the outlet end of the fourth connecting passage 302 is connected to the external oil tank. When the second control valve 30 is in the second state, i.e., the energized state, the pressurized oil in the second control chamber 31 is discharged into the external oil tank through the fourth connecting passage 302. The pressure in the second control chamber 31 decreases, and it can no longer maintain the sealing force on the valve core 4. Under the action of the oil circuit pressure, the valve core 4 moves towards the valve cover 2, so that the side hole 32, the end hole 33 and the movable hole are connected, providing conditions for oil circuit conduction and flow regulation. At this time, the cartridge valve 10 gradually transitions from the closed state to the low flow operating state. When the second control valve 30 is de-energized and returns to the first state, the fourth connecting passage 302 is disconnected, the second connecting passage 301 is reopened, and the pressure oil from the external control oil circuit enters the second control chamber 31, pushing the valve core 4 to move to block the oil circuit and achieve the cut-off function.

[0039] The first control valve 20 also includes a third connecting passage 202. When the first control valve 20 is in the second state, the inlet end of the third connecting passage 202 is connected to the first control chamber 21, and the outlet end of the third connecting passage 202 is connected to an external oil tank. When the first control valve 20 is in the second state, i.e., the energized state, the pressurized oil in the first control chamber 21 is discharged into the external oil tank through the third connecting passage 202. The pressure in the first control chamber 21 decreases, and the oil pressure pushes the valve core 4 to move towards the valve cover 2. The valve core 4 pushes the limit rod 5 to move towards the valve cover 2 to the limit position. At this time, the displacement range of the valve core 4 is further expanded, thereby realizing the switching from small flow conditions to large flow control. When the first control valve 20 is de-energized and returns to the first state, the third connecting passage 202 is disconnected, the first connecting passage 201 is reopened, the pressure oil from the external control oil circuit enters the first control chamber 21, pushing the limit rod 5 to move closer to the valve core 4 to reset, thus re-limiting the displacement of the valve core 4, and the system can switch back to the low flow condition.

[0040] This invention also discloses a control method for controlling the cartridge valve 10 as described above, comprising the following steps: S01, when it is necessary to close the cartridge valve 10, the second control valve 30 is switched to the first state so that the valve core 4 blocks the connection between the first oil circuit connection port 11 and the second oil circuit connection port 12. S02, when it is required to run at the first preset flow rate, the first control valve 20 is switched to the first state and the second control valve 30 is switched to the second state, the first oil circuit connection port 11 and the second oil circuit connection port 12 are connected and the hydraulic oil flow rate is the first preset flow rate; S03, when it is required to run at the second preset flow rate, the first control valve 20 is switched to the second state, and the second control valve 30 is switched to the second state, the first oil circuit connection port 11 and the second oil circuit connection port 12 are connected and the hydraulic oil flow rate is the second preset flow rate; The first preset flow rate is not greater than the second preset flow rate.

[0041] It should be noted that in this method, the first preset flow rate is set to be no greater than the second preset flow rate, wherein the first preset flow rate corresponds to low flow rate demand scenarios such as working progress, and the second preset flow rate corresponds to high flow rate demand scenarios such as fast forward.

[0042] When it is necessary to close the cartridge valve 10, the first control operation is performed: the second control valve 30 is switched to the first state, i.e., the de-energized state. The fourth connecting passage 302 is disconnected, and the second connecting passage 301 is opened. The pressure oil from the external control oil circuit enters the second control chamber 31 through the second oil circuit 50. Under the pressure of the second control chamber 31 and the elastic force of the elastic element 7, the valve core 4 moves away from the valve cover 2, blocking the connection between the first oil circuit connection port 11 and the second oil circuit connection port 12. At this time, regardless of the state of the first control valve 20, the cartridge valve 10 remains stably closed, achieving oil circuit cutoff and meeting the system shutdown and pressure holding requirements.

[0043] When the first preset flow rate is required, the second control operation is performed: the first control valve 20 is switched to the first state (power-off state), and the second control valve 30 is switched to the second state (power-on state). When the first control valve 20 is in the first state, the third connecting passage 202 is disconnected, and pressurized oil is introduced into the first control chamber 21, pushing the limiting rod 5 to move closer to the valve core 4 and forming a limit. When the second control valve 30 is in the second state, the fourth connecting passage 302 is opened, and the pressurized oil in the second control chamber 31 is discharged into the external oil tank, reducing the pressure. Under the action of the oil circuit pressure, the valve core 4 moves closer to the valve cover 2, connecting the first oil circuit connection port 11 and the second oil circuit connection port 12. Because the limiting rod 5 restricts the displacement of the valve core 4, the flow area is fixed, and the hydraulic oil flow rate remains at the first preset flow rate.

[0044] When the second preset flow rate is required, the third control operation is performed: the first control valve 20 is switched to the second state, i.e., the energized state, while the second control valve 30 remains in the second state, i.e., the energized state. When the first control valve 20 is in the second state, the third connecting passage 202 is open, the pressure oil in the first control chamber 21 is discharged into the external oil tank, the pressure decreases, and the oil pressure pushes the valve core 4 towards the valve cover 2. The valve core 4 pushes the limit rod 5 towards the valve cover 2 to the limit position, releasing the displacement restriction on the valve core 4. Under the action of the oil pressure, the valve core 4 further moves towards the valve cover 2, expanding the flow area between the first oil passage connection port 11 and the second oil passage connection port 12, and the hydraulic oil flow rate is increased to the second preset flow rate.

[0045] This control method achieves precise switching between three operating modes by simply switching the control valve state through power-on / off operations. Compared with the complex multi-valve linkage control methods in existing technologies, the steps are simpler, the control response is faster, and the flow regulation relies on the mechanical structure without the need for proportional control elements, reducing the requirements for hydraulic oil cleanliness. This further enhances the advantages of the overall system, such as small size, low cost, and easy maintenance, and can be widely used in various hydraulic equipment that require graded flow control.

[0046] Furthermore, the control method further includes the following steps: When it is necessary to close the cartridge valve 10, the second control valve 30 is switched to the first state. At this time, the second communication passage 301 of the second control valve 30 is connected between the second control chamber 31 and the external control oil circuit. The elastic element 7 acts on the second groove 41 to block the communication between the valve core 4 and the inner hole 32, end hole 33 and the movable hole of the valve cup. At this time, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is H, the distance between the end face of the limiting end 53 and the bottom groove of the second groove 41 is H1, and the distance between the end face of the control end 51 and the pressure cap 6 is H2. When the first preset flow rate is required, the first control valve 20 is switched to the first state, and the second control valve 30 is switched to the second state. At this time, the first connecting passage 201 of the first control valve 20 is connected between the first control chamber 21 and the external control oil circuit, and the fourth connecting passage 302 of the second control valve 30 is connected between the second control chamber 31 and the external oil tank. The end face of the limiting end 53 abuts against the bottom groove of the second groove 41. At this time, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is B1, the distance between the second end face of the valve core 4 and the opening of the end hole 33 of the valve cup is B2, the distance between the end face of the limiting end 53 and the bottom groove of the second groove 41 is B3, and the distance between the end face of the control end 51 and the pressure cap 6 is B4; where B1=H-H1, B2=H1, B3=0, and B4=H2.

[0047] In this embodiment, the first end face of the valve core 4 is the end face closer to the valve cover 2, and the second end face of the valve core 4 is the end face farther from the valve cover 2. In the closed state, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is H. When switching to the first preset flow condition, the valve core 4 abuts against the limiting end 53, therefore the distance the valve core 4 moves towards the valve cover 2 is H1, so the distance B1 between them after the movement is H-H1. In the closed state, the distance between the end face of the limiting end 53 and the bottom of the second groove 41 is H1. When switching to the first preset flow condition, the valve core 4 abuts against the limiting end 53, and the distance the valve core 4 moves towards the valve cover 2 is H1, so the distance B2 between the second end face of the valve core 4 and the opening of the end hole 33 of the valve cup 3 is H1. In the closed state, the distance between the end face of the limiting end 53 and the bottom of the second groove 41 is H1. When switching to the first preset flow condition, the limiting end 53 and the bottom of the second groove 41 are completely in contact, so the gap between them is eliminated, and therefore the distance B3 is 0. In the closed state, the distance between the end face of the control end 51 and the pressure cap 6 is H2. When switching to the first preset flow condition, the position of the control end 51 does not change, so the distance remains unchanged, and therefore the distance B4 is H2.

[0048] When the second preset flow rate is required, the first control valve 20 is switched to the second state, and the second control valve 30 is switched to the second state. At this time, the third connecting passage 202 of the first control valve 20 is connected between the first control chamber 21 and the external oil tank, and the fourth connecting passage 302 of the second control valve 30 is connected between the second control chamber 31 and the external oil tank. The end face of the limiting end 53 abuts against the bottom groove of the second groove 41, and the limiting rod 5 moves away from the valve cup. At this time, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is C1, the distance between the second end face of the valve core 4 and the opening of the end hole 33 of the valve cup is C2, the distance between the end face of the limiting end 53 and the bottom groove of the second groove 41 is C3, and the distance between the end face of the control end 51 and the pressure cap 6 is C4; where C1=0, C2=H, C3=0, and C4=H2-(H-H1).

[0049] Under the first preset flow condition, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is B1 = H - H1. When switching to the second preset flow condition, the valve core 4 moves further towards the valve cover 2, thus the valve core 4 moves until it is completely in contact with the wall of the valve cover 2, so the distance between them, C1, is 0. In the closed state, the distance between the first end face of the valve core 4 and the wall of the valve cover 2 is H. When switching to the second preset flow condition, the valve core 4 moves until it is completely in contact with the wall of the valve cover 2, with a total movement distance of H. Therefore, the distance between the second end face of the valve core 4 and the opening of the end hole 33 of the valve cup 3, C2, is C2 = H. Under the first preset flow condition, the distance between the end face of the limiting end 53 and the bottom of the second groove 41 is B3 = 0. When switching to the second preset flow condition, the limiting end 53 remains in contact with the bottom of the second groove 41, so the gap is always 0, and therefore the distance, C3, is 0. In the closed state, the distance between the end face of the control terminal 51 and the pressure cap 6 is H2. When switching to the second preset flow condition, the valve core 4 moves a distance of H-H1 from the first preset flow condition to the second preset flow condition. The limiting end 53 is always in contact with the valve core 4. Therefore, the limiting rod 5 moves a distance of H-H1 away from the valve cup 3. The distance between the control terminal 51 and the pressure cap 6 is shortened by H-H1. So the distance C4 is H2-(H-H1).

[0050] The control method further includes the following steps: When it is necessary to increase the second preset flow rate, rotate the adjusting rod 8 so that the end of the adjusting rod 8 closest to the control end 51 is away from the bottom of the first tank 22; When it is necessary to reduce the second preset flow rate, rotate the adjusting rod 8 so that the end of the adjusting rod 8 closest to the control end 51 is close to the bottom of the first tank 22.

[0051] One end of the adjusting rod 8 passes through the pressure cap 6 and enters the first groove 22, abutting against the control end 51. The other end of the adjusting rod 8 is sleeved and abuts against the wall of the pressure cap 6. By rotating the adjusting rod 8, the insertion length of the adjusting rod 8 in the first groove 22 can be changed, thereby limiting the movement limit of the control end 51, indirectly adjusting the maximum retraction distance of the limit rod 5, and finally changing the maximum displacement and flow area of ​​the valve core 4 to achieve the increase or decrease adjustment of the second preset flow rate.

[0052] When a second preset flow rate is required, the limiting position of the adjusting rod 8 relative to the control end 51 is moved backward, providing the control end 51 with greater movement space and increasing the maximum retraction distance of the limiting rod 5 away from the valve cup 3. Under the second preset flow rate condition, the valve core 4 can move further towards the valve cover 2 under the action of oil circuit pressure, further expanding the flow area between the side hole 32 and the end hole 33, thereby increasing the hydraulic oil flow rate and meeting the requirements of higher efficiency and faster forward operation.

[0053] When the second preset flow rate needs to be reduced, the limiting position of the adjusting rod 8 relative to the control end 51 moves forward, shortening the movement space of the control end 51 and limiting the retraction distance of the limiting rod 5 away from the valve cup 3. Under the second preset flow rate condition, the maximum displacement of the valve core 4 is reduced, the flow area between the side hole 32 and the end hole 33 is correspondingly reduced, and the hydraulic oil flow rate decreases accordingly. This is suitable for operating scenarios where the rapid traverse speed is constrained, and avoids system vibration caused by excessive flow.

[0054] The above are preferred embodiments of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A cartridge valve, characterized in that, The valve includes a valve body, a valve cover located at one end of the valve body, and a valve cup and a valve core located inside the valve body. The valve body includes a first oil passage connection port and a second oil passage connection port. The first oil passage connection port is connected to external pressure oil, and the second oil passage connection port is connected to an actuator. The valve core is used to control the on / off state and flow rate between the first oil passage connection port and the second oil passage connection port. The valve cover is provided with a first control chamber, and a limiting rod is provided between the valve cover and the valve core. The first control chamber is used to control the position of the limiting rod. The valve cup is provided with a second control chamber, which is located between the valve cover and the valve core. The second control chamber is used to control the position of the valve core. The end of the limiting rod can abut against the valve core to limit the displacement of the valve core.

2. The cartridge valve according to claim 1, characterized in that, The valve cover has a first groove, the limiting rod includes a control end, the control end is movably disposed in the first groove, the cartridge valve also includes a pressure cap, the pressure cap is used to cover the first groove and form a sealed cavity, the control end and one inner wall of the pressure cap form the first control cavity, and the control end and the bottom of the first groove form a breathing cavity. The limiting rod also includes a limiting section extending from the control end toward the valve core. The valve core has a second groove with its opening facing the valve cover. The end of the limiting section is a limiting end that can be inserted into the second groove and abut against the bottom of the second groove.

3. The cartridge valve according to claim 2, characterized in that, The valve cup has a movable hole, the valve core is disposed in the movable hole and can move in the movable hole, and the second control cavity is formed between the end of the valve core near the valve cover and the valve cover; The valve cup has a side hole on its side and an end hole at its end. The first oil passage is connected to the side hole, and the second oil passage is connected to the end hole. When the valve core moves toward the valve cover, the side hole, the end hole, and the movable hole are connected to each other. When the valve core moves away from the valve cover, the valve core blocks the connection between the side hole, the end hole, and the movable hole.

4. The cartridge valve according to claim 2, characterized in that, The cartridge valve also includes an elastic element disposed in the second groove, one end of which abuts against the bottom of the second groove, and the other end of which abuts against the valve cover.

5. The cartridge valve according to claim 2, characterized in that, The cartridge valve also includes an adjusting rod and a locking nut. One end of the adjusting rod passes through the gland and enters the first groove, abutting against the control end. The locking nut is sleeved on the other end of the adjusting rod and abuts against the wall of the gland. The adjusting rod is used to control the movement stroke of the limiting rod.

6. A hydraulic system, characterized in that, The valve includes a cartridge valve as described in any one of claims 1-5, and further includes a first control valve and a second control valve, wherein the first control valve is used to control the first control chamber, and the second control valve is used to control the second control chamber. The first control valve includes a first communication passage. When the first control valve is in a first state, the inlet end of the first communication passage is connected to an external control oil circuit, and the outlet end of the first communication passage is connected to the first control chamber through the first oil circuit. The second control valve includes a second communication passage. When the second control valve is in the first state, the inlet end of the second communication passage is connected to an external control oil circuit, and the outlet end of the second communication passage is connected to the second control chamber through a second oil circuit.

7. The hydraulic system according to claim 6, characterized in that, The first control valve further includes a third communication passage. When the first control valve is in the second state, the inlet end of the third communication passage is connected to the first control chamber, and the outlet end of the third communication passage is connected to an external oil tank. The second control valve also includes a fourth communication passage. When the second control valve is in the second state, the inlet end of the fourth communication passage is connected to the second control chamber, and the outlet end of the fourth communication passage is connected to the external oil tank.

8. A control method, characterized in that, For controlling the cartridge valve as described in any one of claims 1-5, the following steps are included: When it is necessary to close the cartridge valve, switch the second control valve to the first state so that the valve core blocks the connection between the first oil circuit port and the second oil circuit port; When it is required to run at the first preset flow rate, the first control valve is switched to the first state and the second control valve is switched to the second state, the first oil circuit connection port and the second oil circuit connection port are connected and the hydraulic oil flow rate is the first preset flow rate; When it is required to run at the second preset flow rate, the first control valve is switched to the second state, and the second control valve is switched to the second state. The first oil circuit connection port and the second oil circuit connection port are connected and the hydraulic oil flow rate is the second preset flow rate. The first preset flow rate is not greater than the second preset flow rate.

9. The control method according to claim 8, characterized in that, It also includes the following steps: When the cartridge valve needs to be closed, the second control valve is switched to the first state. At this time, the second communication passage of the second control valve is connected between the second control chamber and the external control oil circuit. The elastic element acts on the second groove to block the communication between the valve core, the end hole and the movable hole of the valve cup. At this time, the distance between the first end face of the valve core and the valve cover wall is H, the distance between the end face of the limit end and the bottom groove of the second groove is H1, and the distance between the end face of the control end and the gland is H2. When the first preset flow rate is required, the first control valve is switched to the first state, and the second control valve is switched to the second state. At this time, the first connecting passage of the first control valve is connected between the first control chamber and the external control oil circuit, and the fourth connecting passage of the second control valve is connected between the second control chamber and the external oil tank. The end face of the limiting end abuts against the bottom groove of the second groove. At this time, the distance between the first end face of the valve core and the valve cover wall is B1, the distance between the second end face of the valve core and the end hole opening of the valve cup is B2, the distance between the end face of the limiting end and the bottom groove of the second groove is B3, and the distance between the end face of the control end and the gland is B4; where B1=H-H1, B2=H1, B3=0, and B4=H2. When the second preset flow rate is required, the first control valve is switched to the second state, and the second control valve is switched to the second state. At this time, the third connecting passage of the first control valve is connected between the first control chamber and the external oil tank, and the fourth connecting passage of the second control valve is connected between the second control chamber and the external oil tank. The end face of the limiting end abuts against the bottom groove of the second groove and the limiting rod moves away from the valve cup. At this time, the distance between the first end face of the valve core and the valve cover wall is C1, the distance between the second end face of the valve core and the end hole opening of the valve cup is C2, the distance between the end face of the limiting end and the bottom groove of the second groove is C3, and the distance between the end face of the control end and the pressure cap is C4; where C1=0, C2=H, C3=0, C4=H2-(H-H1).

10. The control method according to claim 8, characterized in that, It also includes the following steps: When it is necessary to increase the second preset flow rate, rotate the adjusting rod so that the end of the adjusting rod closer to the control end is away from the bottom of the first tank. When it is necessary to reduce the second preset flow rate, rotate the adjusting rod so that the end of the adjusting rod closer to the control end is close to the bottom of the first tank.

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