Pilot-following proportional valve

Abstract

This invention relates to the field of hydraulic valve technology, and in particular to a pilot-operated proportional valve. The pilot-operated proportional valve includes: a valve sleeve having cavities extending through both ends of its axis; each cavity comprising a control section, an inlet section, and an outlet section, the inlet section and outlet section respectively having an inlet port and an outlet port; a main valve core, movable between an open position connecting the inlet section and the outlet section and a closed position isolating the inlet section and the outlet section; the main valve core having pressure relief channels extending through both ends of its axis; wherein the valve sleeve has a first channel and a second channel communicating with the control section to drive the main valve core to move; the main valve core has a first through hole radially connecting the pressure relief channels and the control section; the pressure relief channels have a pilot valve core that moves axially to control the on / off state of the first through hole and the pressure relief channels.

Description

Technical Field

[0001] This invention relates to the field of hydraulic valve technology, and in particular to a pilot-operated proportional valve. Background Technology

[0002] Currently, pilot-operated proportional valves can achieve proportional control of valve opening. However, the method used is as follows: the valve sleeve is sleeved with the main valve core, and a control segment is formed at the left and right ends of the main valve core. The pilot circuit connects the two control segments, and the pressure of the liquid entering the two control segments is adjusted by the pressure reducing valve set in the pilot circuit, thereby controlling the displacement of the main valve core and achieving proportional control of the valve opening.

[0003] However, this method requires maintaining pressure balance within the two control segments, which can easily lead to valve core oscillation instability during use. It is difficult to control and requires not only an additional pressure reducing valve but also high precision in the machining and fitting of parts, which greatly increases the cost due to the high machining difficulty. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in related technologies. To this end, the present invention proposes a pilot-operated proportional valve to simplify the structure of the pilot-operated proportional valve, improve the stability of the valve core movement, reduce the control difficulty, and ensure consistent opening and closing characteristics.

[0005] This invention provides a pilot-operated proportional valve, comprising:

[0006] A valve sleeve is provided with a cavity extending through both ends of the valve sleeve along its axis. The cavity includes a control section, a liquid inlet section, and a liquid outlet section. The liquid inlet section and the liquid outlet section are respectively provided with a liquid inlet and a liquid outlet.

[0007] The main valve core moves between an open position connecting the inlet section and the outlet section and a closed position separating the inlet section and the outlet section. The main valve core is provided with a pressure relief channel extending along its axis.

[0008] The valve sleeve is provided with a first channel and a second channel that communicate with the control section to drive the main valve core to move; the main valve core is provided with a first through hole that connects the pressure relief channel and the control section radially; the pressure relief channel is provided with a pilot valve core that moves axially thereto to control the on / off state of the first through hole and the pressure relief channel.

[0009] According to the present invention, a pilot-operated proportional valve further includes a driving device connected to the pilot valve core and fixed at the left end of the cavity, for driving the pilot valve core to move relative to the pressure relief channel;

[0010] The pilot valve core is provided with a second through hole extending from its end face to its side wall. The second through hole is located to the right of the first through hole and is used to give the pilot valve core an initial position that isolates the first through hole from the pressure relief channel.

[0011] According to a pilot-operated proportional valve provided by the present invention, the pressure relief channel is provided with a circumferentially extending balance groove along its sidewall, and the first through hole extends from the bottom surface of the balance groove to the control section.

[0012] When the end of the pilot valve core moves to the right side of the balance groove, the balance groove forms an annular cavity around the pilot valve core.

[0013] According to the present invention, a pilot-operated proportional valve is provided, wherein the main valve core is provided with a control part that slides within the control section, and the valve sleeve is provided with a first channel and a second channel for supplying liquid into the control section to drive the main valve core to move.

[0014] When the flow rate of liquid entering the control section through the first channel is greater than the flow rate of liquid exiting the control section through the second through hole, the main valve core moves to the right; or, when the flow rate of liquid entering the control section through the first channel is less than the flow rate of liquid exiting the control section through the second through hole, the main valve core moves to the left.

[0015] The first channel connects from the outside of the valve sleeve to the left side of the control section, and the second channel connects from the liquid inlet to the right side of the control section. The pipeline is connected to the first channel and the second channel.

[0016] According to the present invention, a pilot-operated proportional valve is provided in which a return liquid section with a return liquid port is provided at the right end of the cavity, the valve sleeve is provided with a cylindrical part in the return liquid section, the cylindrical part and the inner wall of the return liquid section are provided with an annular gap, and the right end of the main valve core is slidably inserted into the cylindrical part.

[0017] According to the present invention, a pilot-operated proportional valve further includes a return valve core slidably sleeved on the outside of the cylindrical portion, the return valve core moving between an open position connecting the outlet section and the return section and a closed position separating the outlet section and the return section.

[0018] According to a pilot-operated proportional valve provided by the present invention, a third channel is provided on the right side of the return liquid section for conveying liquid into the annular gap between the cylindrical part and the return liquid section to drive the return liquid valve core to move.

[0019] A reversing valve is provided between the third channel and the return port to control the connection between the third channel and the return port, or between the third channel and the pipeline.

[0020] According to the present invention, a pilot-operated proportional valve is provided on the side wall of the pressure relief channel, and the two seals are respectively located on the left and right sides of the balance groove.

[0021] According to the present invention, a pilot-operated proportional valve is provided in which the cavity is provided with a guide section, the guide section is located to the left of the control section, the cross-sectional diameter of the guide section is smaller than the cross-sectional diameter of the control section, and the first channel is located adjacent to the guide section and the control section.

[0022] The left end of the main valve core is configured as a guide portion that cooperates with the guide segment, and the guide portion is slidably inserted into the guide segment.

[0023] According to the present invention, a pilot-operated proportional valve controls the pipeline to deliver high-pressure liquid to the control section, drives the pilot valve core to move to the left by a set distance, and repeats the above-mentioned moving process until the main valve core reaches a preset opening degree.

[0024] The above-described one or more technical solutions of this invention have at least one of the following technical effects:

[0025] The sliding of the pilot valve core connects the first through-hole to the control section, allowing the liquid in the control section to be discharged through the pressure relief channel. This results in the opening force on the main valve core being greater than the closing force, causing the main valve core to slide to the left and connect the inlet and outlet sections. When the pilot-operated proportional valve is in the open state, even a slight movement of the pilot valve core changes the pressure in the control section, thus altering the force balance of the main valve core. Consequently, the main valve core moves almost simultaneously with the pilot valve core, improving the response speed of the pilot-operated proportional valve and ensuring high control accuracy, stability, and consistency.

[0026] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted by the present invention, and the advantages brought about by the technical features of these technical solutions as described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings, or will be learned through the practice of the present invention. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a schematic diagram of the pilot-operated proportional valve in its initial state (main valve core inlet closed) according to an embodiment of the present invention.

[0029] Figure 2 This is a schematic diagram of the pilot valve core of the pilot-operated proportional valve provided in an embodiment of the present invention when it moves to a critical state (the main valve core inlet is about to open).

[0030] Figure 3 This is a schematic diagram of the pilot valve core of the pilot-operated proportional valve provided in the embodiment of the present invention moving to the point where the first through hole and the second through hole are connected (the process of opening the liquid inlet of the main valve core).

[0031] Figure 4 This is a schematic diagram of the pilot valve core of the pilot-operated proportional valve provided in the embodiment of the present invention moving to the equilibrium state (the main valve core stops moving).

[0032] Figure label:

[0033] 100, Valve sleeve; 110, Cavity; 120, Guide section; 130, Control section; 131, First channel; 140, Liquid inlet section; 141, Liquid inlet; 142, Second channel; 150, Liquid outlet section; 151, Liquid outlet; 160, Liquid return section; 161, Liquid return port; 162, Third channel; 170, Cylindrical section; 200, Main valve core; 210, Pressure relief channel; 211, Balance groove; 212, Seal; 220, First through hole; 230, Guide section; 240, Control section; 300, Pilot valve core; 310, Second through hole; 400, Liquid return valve core; 500, Piping; 600, Drive unit; 700, Directional valve; 800, Throttle valve. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0035] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not 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 the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0036] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0037] In embodiments of the present 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 indicates 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 indicates that the first feature is at a lower horizontal level than the second feature.

[0038] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present 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.

[0039] In this invention, a pilot proportional valve refers to a device that combines the functions of a pilot valve and a main valve, and can adjust the flow rate or pressure of a fluid according to an input signal (usually an electrical signal) to more accurately control the flow rate of the supplied fluid and achieve continuous and precise adjustment of components such as hydraulic cylinders and hydraulic supports.

[0040] like Figure 1 As shown in the embodiment of the present invention, a pilot-operated proportional valve is introduced. The pilot-operated proportional valve mainly includes: a valve sleeve 100, a main valve core 200, a pilot valve core 300, a return valve core 400, and a drive device 600.

[0041] Specifically, the valve sleeve 100 is provided with cavities 110 extending through both ends along its axis. From left to right, the cavities 110 are configured as a guide section 120, a control section 130, an inlet section 140, an outlet section 150, and a return section 160. The inlet section 140, outlet section 150, and return section 160 are respectively provided with an inlet port 141, an outlet port 151, and a return port 161.

[0042] The main valve core 200 moves between an open position connecting the inlet section 140 and the outlet section 150 and a closed position separating the inlet section 140 and the outlet section 150. The main valve core 200 is provided with a pressure relief channel 210 extending along its axis.

[0043] Furthermore, the valve sleeve 100 is provided with a first channel 131 and a second channel 142 that communicate with the control section 130 to drive the main valve core 200 to move. The valve sleeve 100 has an external conduit 500 that communicates with the first channel 131 and the inlet 141. The conduit 500 communicates with the first channel 131 and the second channel 142, respectively. The main valve core 200 is provided with a first through hole 220. The first through hole 220 extends radially along the main valve core 200 and penetrates the side wall of the main valve core 200. Thus, the first through hole 220 connects the control section 130 with the pressure relief channel 210.

[0044] In addition, a pilot valve core 300 is provided within the pressure relief channel 210, which cooperates with and slides along its axial direction. The left end of the pilot valve core 300 protrudes from the left end of the pressure relief channel 210, and the right end of the pilot valve core 300 is embedded within the pressure relief channel 210. Furthermore, the right end of the pilot valve core 300 can reciprocate between the left and right sides of the first through hole 220 to control the on / off state of the first through hole 220 and the pressure relief channel 210.

[0045] Furthermore, the main valve core 200 is provided with a pressure relief channel 210 extending through both ends of its axis.

[0046] In this embodiment, the sliding of the pilot valve core 300 allows the first through hole 220 to connect with the control section 130, thereby draining the liquid in the control section 130 through the pressure relief channel 210. This results in the opening force on the main valve core 200 being greater than the closing force, and the main valve core 200 sliding to the left connects the inlet section 140 with the outlet section 150. When the pilot-operated proportional valve is in the open state, a slight movement of the pilot valve core 300 changes the pressure in the control section 130, thereby changing the force balance state of the main valve core 200. As a result, the main valve core 200 moves almost simultaneously with the pilot valve core 300, improving the response speed of the pilot-operated proportional valve and ensuring its high control accuracy, stability, and consistency.

[0047] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0048] To accurately control the movement distance of the pilot valve core 300 within the pressure relief channel 210, a drive device 600 is provided at the left end of the valve sleeve 100. The drive device 600 is connected to the pilot valve core 300 and is used to drive the pilot valve core 300 to move relative to the pressure relief channel 210. Preferably, the drive device 600 is fixed to the left end of the cavity 110 and is arranged to coincide with the central axis of the cavity 110.

[0049] Furthermore, a second through hole 310 is provided at the right end of the pilot valve core 300 to allow the pilot valve core 300 to slide smoothly within the pressure relief channel. The second through hole 310 extends from the right end face of the pilot valve core 300 to the side wall of the pilot valve core 300. When the pilot valve core 300 is in the initial position, the second through hole 310 is located to the right of the first through hole 220, which is used to isolate the pilot valve core 300 from the first through hole 220 and the pressure relief channel 210.

[0050] Furthermore, the drive unit 600 is rigidly connected to the pilot valve core 300. The pilot valve core 300 is in... Figure 1 In the position shown, the second through hole 310 of the pilot valve core 300 is isolated from the control section 130. In the control section 130 located to the left of the main valve core 200, the liquid pressure is equal to the inlet pressure of the pipeline 500. In the control section 130 located to the right of the main valve core 200, because it is connected to the inlet port 141 through the second passage 142, the liquid pressure is also equal to the inlet pressure of the pipeline 500.

[0051] However, the annular area of ​​the left control segment 130 of the main valve core 200 is larger than the area of ​​the right control segment 130 of the main valve core 200, so the resultant force on the main valve core 200 is to the right. The main valve core 200 and the cavity 110 are separated by a conical surface abutment seal, which separates the inlet port 141 and the outlet port 151.

[0052] Furthermore, by driving the pilot valve core 300 to slide within the pressure relief channel 210 through the drive device 600, the position of the main valve core 200 can follow the position of the pilot valve core 300, that is, the main valve core 200 moves with the pilot valve core 300.

[0053] For example, the drive unit 600 moves the pilot valve core 300 to the left by a set distance. When the second through hole 310 of the pilot valve core 300 connects with the first through hole 220, the pressure relief channel 210 connects with the control section 130 on the left side of the main valve core 200. At this time, the liquid in the control section 130 on the left side of the main valve core 200 connects with the return port 161 through the first through hole 220, the second through hole 310, and the pressure relief channel 210. The pressure in the control section 130 on the left side of the main valve core 200 decreases, and the pipeline 500 continuously supplies high-pressure liquid to the control section 130 on the left side of the main valve core 200 through the first channel 131.

[0054] However, a throttle valve 800 is connected in series in the pipeline connecting pipeline 500 and the first channel 131. Since the throttle valve 800 has a certain pressure drop effect, the pressure drop increases with the flow rate. Simultaneously, the pressure in the control section 130 on the right side of the main valve core 200 is always equal to the system pressure. Therefore, when the pressure in the control section 130 on the left side of the main valve core 200 drops to a certain value, due to the pressure difference between the two sides, the liquid will drive the main valve core 200 to move to the left until it reaches the second through-hole 310 of the pilot valve core 300, forcing it to disconnect from the first through-hole 220, at which point the main valve core 200 stops moving. Thus, the main valve core 200 completes the process of following the pilot valve core 300. Furthermore, the inlet 141 and outlet 151 are connected, maintaining a specific opening. If the opening between the inlet 141 and the outlet 151 is increased to increase the flow rate, the control drive device 600 will again move the pilot valve core 300 a certain distance to the left, and the main valve core 200 will follow. Repeating the above steps will complete the opening action of the main valve core 200.

[0055] Therefore, by controlling the displacement of the pilot valve core 300 through the drive device 600, the displacement of the main valve core 200 can be controlled, thus achieving precise and continuous control of the opening degree of the main valve core 200. This not only avoids the need to install a valve core displacement sensor, but also greatly simplifies the overall structure of the pilot proportional valve, making the processing and manufacturing of the pilot proportional valve easier and cheaper.

[0056] Furthermore, the effective throttling area of ​​the second through hole 310 is greater than the effective throttling area of ​​the throttle valve 800, making the discharge capacity of the pilot valve core 300 greater than the inlet capacity of the throttle valve 800.

[0057] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0058] To ensure consistent starting characteristics of the main valve core 200 during control, a balanced design is implemented for the main valve core 200. Specifically, the pressure relief channel 210 is provided with a circumferentially extending balance groove 211 along its sidewall. A first through hole 220 extends from the bottom surface of the balance groove 211 and penetrates to the control section 130.

[0059] When the end of the pilot valve core 300 moves to the right side of the balance groove 211, the balance groove 211 forms an annular cavity around the pilot valve core 300. Thus, when the pilot valve core 300 slides within the pressure relief channel 210, there is a certain buffer space between the second through hole 310 and the first through hole 220 of the pilot valve core 300, preventing violent fluctuations caused by the instantaneous opening and closing of the second through hole 310 and the first through hole 220, thereby improving the reliability and stability of the pilot proportional valve.

[0060] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0061] The main valve core 200 is provided with a control part 240 that slides within the control section 130. The valve sleeve 100 is provided with a pipe 500 connecting the first channel 131 and the liquid inlet 141, for supplying liquid into the control section 130 to drive the main valve core 200 to move.

[0062] When the flow rate of liquid entering the control section 130 through the first channel 131 is greater than the flow rate of liquid exiting the control section 130 through the second through hole 310, the main valve core 200 moves to the right.

[0063] Alternatively, when the liquid flow rate entering the control section 130 through the first channel 131 is less than the liquid flow rate exiting the control section 130 through the second through hole 310, the main valve core 200 moves to the left.

[0064] The first channel 131 connects from the outside of the valve sleeve 100 to the left side of the control section 130. The second channel 142 connects from the inlet 141 to the right side of the control section 130. The pipeline 500 is connected to the first channel 131 and the second channel 142.

[0065] like Figure 1 As shown, in the initial state, the pilot-operated proportional valve 700 is not energized, the high-pressure liquid is disconnected from the third channel 162, and the return valve core 400 is located at the right end of the return section 160, with the outlet port connected to the return port.

[0066] like Figure 2As shown, when the reversing valve 700 is energized, the high-pressure liquid connects to the third channel 162. Under the action of the high-pressure liquid, the return valve core 400 moves to the left end of the return section 160, at which point the outlet and return port are disconnected. While keeping the reversing valve 700 energized, the drive device 600 drives the pilot valve core 300 to move to the left. When the pilot valve core 300 moves to the point where the first through hole 220 is about to connect with the second through hole 310, it is in a critical state.

[0067] In the critical state, if the pilot valve core 300 continues to move to the left, the control section 130 will connect with the second through hole 310, the pressure in the control section 130 will decrease, the force balance will be broken, and under the action of the unbalanced force, the main valve core 200 will start to move to the left.

[0068] like Figure 4 As shown, assuming the pilot valve core 300 remains stationary after moving to a certain position, and the main valve core 200 follows suit, when the main valve core 200 moves to... Figure 4 At the indicated position, the second through hole 310 on the pilot valve core 300 is in a semi-open, semi-closed state, and the main valve core 200 rebalances and maintains its position. In this balanced operating state, as long as the pilot valve core 300 moves to the left, the force balance on both sides of the control section 240 of the main valve core 200 will be broken, and the main valve core 200 will follow the pilot valve core 300 to the left until it moves again until the second through hole 310 on the pilot valve core 300 is in a semi-open, semi-closed state, at which point it will rebalance.

[0069] Similarly, in this balanced working state, as long as the pilot valve core 300 moves to the right, the force balance on the left and right sides of the control part of the main valve core 200 will be broken, the pressure on the left side of the control part of the main valve core 200 will increase, driving the main valve core 200 to move to the right until it moves again to the second through hole 310 on the pilot valve core 300 in a half-open and half-closed state, and then the balance is restored.

[0070] As the pilot valve core 300 moves to the right, the main valve port closes continuously. When the main valve core 200 just contacts the valve sleeve and closes, the second through hole 310 on the pilot valve core 300 is still in a semi-open and semi-closed equilibrium state. In order to reliably seal the main valve port, the pilot valve core 300 needs to continue to move to the right until the control section 130 is no longer connected to the second through hole 310. At this time, the pressure on the left side of the control section 240 of the main valve core 200 will increase, ensuring that the main valve core 200 is tightly sealed on the conical surface of the valve sleeve 100.

[0071] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0072] The right end of the cavity 110 is provided with a return section 160 having a return port 161. The valve sleeve 100 has a cylindrical portion 170 in the return section 160. There is an annular gap between the cylindrical portion 170 and the inner wall of the return section 160. The right end of the main valve core 200 is slidably inserted into the cylindrical portion 170.

[0073] Furthermore, the pilot-operated proportional valve also includes a return valve core 400 that is slidably sleeved on the outside of the cylindrical portion 170. The return valve core 400 moves between an open position that connects the outlet section 150 and the return section 160 and a closed position that isolates the outlet section 150 and the return section 160.

[0074] A third channel 162 is provided on the right side of the return liquid section 160 for conveying liquid into the annular gap between the cylindrical part 170 and the return liquid section 160 to drive the return liquid valve core 400 to move.

[0075] A reversing valve 700 is provided between the third channel 162 and the return port 161 to control the connection between the third channel 162 and the return port 161, or to the pipeline 500.

[0076] Specifically, the directional valve 700 is configured as a solenoid switch valve. When the solenoid switch valve is in the following position... Figure 1 In the de-energized position shown, the third channel 162 on the right side of the return valve core 400 is connected to the return port 161 via a solenoid valve. At this time, the outlet port 151 and the return port 161 are connected. Furthermore, the pilot-operated proportional valve in this invention is a two-position three-way structure. It has three working ports: inlet port P, outlet port A, and return port R. The initial state is: inlet port 141 is disconnected from outlet port 151, and outlet port 151 is connected to return port 161.

[0077] The outlet 151 is usually connected to the working chamber of the hydraulic cylinder. When the hydraulic cylinder needs to extend, the inlet 141 needs to be connected to the outlet 151, and the outlet 151 needs to be disconnected from the return port 161.

[0078] At this time, the pilot-operated proportional valve operates as follows: First, the return valve core 400 is closed, i.e., the solenoid switch valve is energized. The high-pressure liquid in pipeline 500 enters the right side of the return valve core 400 through the solenoid switch valve and the third channel 162, pushing the return valve core 400 to the left to disconnect the connection between the outlet section 150 and the return section 160. That is, it isolates the outlet 151 from the return port 161.

[0079] Then, the drive unit 600 moves the pilot valve core 300 to the left by a set distance. When the second through hole 310 of the pilot valve core 300 connects with the first through hole 220, the pressure relief channel 210 connects with the control section 130 on the left side of the main valve core 200. At this time, the liquid in the control section 130 on the left side of the main valve core 200 connects with the return port 161 through the first through hole 220, the second through hole 310, and the pressure relief channel 210. The pressure in the control section 130 on the left side of the main valve core 200 decreases, and the pipeline 500 continuously supplies high-pressure liquid to the control section 130 on the left side of the main valve core 200 through the first channel 131.

[0080] However, a throttle valve 800 is connected in series in the pipeline connecting pipeline 500 and the first channel 131. Since the throttle valve 800 has a certain pressure drop effect, the pressure drop increases with the flow rate. Simultaneously, the pressure in the control section 130 on the right side of the main valve core 200 is always equal to the system pressure. Therefore, when the pressure in the control section 130 on the left side of the main valve core 200 drops to a certain value, due to the pressure difference between the two sides, the liquid will drive the main valve core 200 to move to the left until it reaches the second through-hole 310 of the pilot valve core 300, forcing it to disconnect from the first through-hole 220, at which point the main valve core 200 stops moving. Thus, the main valve core 200 completes the process of following the pilot valve core 300. Furthermore, the inlet 141 and outlet 151 are connected, maintaining a specific opening. If the opening between the inlet 141 and the outlet 151 is increased to increase the flow rate, the control drive device 600 will again move the pilot valve core 300 a certain distance to the left, and the main valve core 200 will follow. Repeating the above steps will complete the opening action of the main valve core 200.

[0081] In this embodiment, the control of the main valve core 200 and the return valve core 400 is separated, and each is controlled by a drive device 600 and a two-position three-way solenoid valve, which ensures the reliability of the structure and achieves precise control of the position of the main valve core 200. Moreover, the movement control of the main valve core 200 can be achieved by controlling the pressure of the control segment 130 located at the left end of the pilot proportional valve, which greatly simplifies the structure of the valve sleeve 100 and reduces the processing difficulty and cost of the pilot proportional valve.

[0082] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0083] To improve the sealing between the relative moving surfaces of the pilot valve core 300 and the main valve core 200, a sealing element 212 is also provided on the side wall of the pressure relief channel 210. The two sealing elements 212 are located on the left and right sides of the balance groove 211, respectively.

[0084] Furthermore, the cavity 110 is provided with a guide segment 120. The guide segment 120 is located to the left of the control segment 130. The cross-sectional diameter of the guide segment 120 is smaller than the cross-sectional diameter of the control segment 130. The first channel 131 is located adjacent to the guide segment 120 and the control segment 130.

[0085] The left end of the main valve core 200 is configured as a guide portion 230 that mates with the guide section 120. The guide portion 230 is slidably inserted into the guide section 120.

[0086] In this embodiment, the pilot valve core 300 is configured as a spool valve with a seal, which is suitable for hydraulic systems with water-based media, such as those used in underground coal mines, as well as for oil-based hydraulic products. It also reduces the friction between the pilot valve core 300 and the main valve core 200, further reducing the driving power required by the drive device 600.

[0087] Based on the above embodiments, another embodiment of the present invention introduces a pilot-operated proportional valve.

[0088] The system establishes a correlation parameter between the opening degree of the main valve core 200 and the displacement of the pilot valve core 300. High-pressure liquid is supplied from the control line 500 to the control section 130. This drives the pilot valve core 300 to move a predetermined distance to the left. This movement process is repeated until the main valve core 200 reaches the preset opening degree.

[0089] Specifically, firstly, the correlation parameters between the opening degree of the main valve core 200 and the displacement of the pilot valve core 300 are preset to obtain a linear relationship in which the opening degree of the main valve core 200 and the displacement of the pilot valve core 300 are positively correlated.

[0090] Then, high-pressure liquid is supplied to the pilot-operated proportional valve through pipeline 500, and the drive device 600 is controlled to drive the pilot valve core 300 to move according to a set distance. The specific steps are as follows: the return valve core 400 is closed, and the high-pressure liquid in pipeline 500 enters the right side of the return valve core 400 through the solenoid switch valve and the third channel 162, pushing the return valve core 400 to move to the left to disconnect the connection between the outlet section 150 and the return section 160; the drive device 600 drives the pilot valve core 300 to move to the left by a set distance, and the liquid drives the main valve core 200 to move to the left to complete the process of following the pilot valve core 300.

[0091] Finally, if the opening between the inlet 141 and the outlet 151 is increased, the control drive device 600 will again drive the pilot valve core 300 to move to the left a certain distance, and the main valve core 200 will follow the pilot valve core 300. This step is repeated until the set opening is reached.

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pilot-operated proportional valve, characterized in that, include: A valve sleeve (100) is provided with a cavity (110) extending through both ends of the valve sleeve (100) along its axis. The cavity (110) includes a control section (130), an inlet section (140) and an outlet section (150). The inlet section (140) and the outlet section (150) are respectively provided with an inlet (141) and an outlet (151). The main valve core (200) moves between an open position connecting the liquid inlet section (140) and the liquid outlet section (150) and a closed position separating the liquid inlet section (140) and the liquid outlet section (150). The main valve core (200) is provided with a pressure relief channel (210) extending along its axis. The valve sleeve (100) is provided with a first channel (131) and a second channel (142) communicating with the control section (130) to drive the main valve core (200) to move; the main valve core (200) is provided with a first through hole (220) radially communicating with the pressure relief channel (210) and the control section (130); the pressure relief channel (210) is provided with a pilot valve core (300) that moves axially thereon, for controlling the on / off state of the first through hole (220) and the pressure relief channel (210); It also includes a drive device (600), which is connected to the pilot valve core (300) and fixed to the left end of the cavity (110), for driving the pilot valve core (300) to move relative to the pressure relief channel (210); The pilot valve core (300) is provided with a second through hole (310) extending from its end face to its side wall. The second through hole (310) is located to the right of the first through hole (220) and is used to give the pilot valve core (300) an initial position that isolates the first through hole (220) from the pressure relief channel (210). The pressure relief channel (210) is provided with a circumferentially extending balance groove (211) along its sidewall, and the first through hole (220) extends from the bottom surface of the balance groove (211) through to the control section (130). When the end of the pilot valve core (300) moves to the right side of the balance groove (211), the balance groove (211) forms an annular cavity around the pilot valve core (300).

2. The pilot-operated proportional valve according to claim 1, characterized in that, The main valve core (200) is provided with a control part (240) that slides within the control section (130), and the valve sleeve (100) is provided with a pipe (500) outside the valve sleeve (100) that connects the first channel (131) and the liquid inlet (141) for supplying liquid into the control section (130) to drive the main valve core (200) to move. When the flow rate of liquid entering the control section (130) through the first channel (131) is greater than the flow rate of liquid exiting the control section (130) through the second through hole (310), the main valve core (200) moves to the right; or, when the flow rate of liquid entering the control section (130) through the first channel (131) is less than the flow rate of liquid exiting the control section (130) through the second through hole (310), the main valve core (200) moves to the left. The first channel (131) is connected from the outside of the valve sleeve (100) to the left side of the control section (130), and the second channel (142) is connected from the liquid inlet (141) to the right side of the control section (130). The pipeline (500) is connected to the first channel (131) and the second channel (142).

3. The pilot-operated proportional valve according to claim 2, characterized in that, The right end of the cavity (110) is also provided with a return section (160) having a return port (161). The valve sleeve (100) has a cylindrical part (170) in the return section (160). There is an annular gap between the cylindrical part (170) and the inner wall of the return section (160). The right end of the main valve core (200) is slidably inserted into the cylindrical part (170).

4. The pilot-operated proportional valve according to claim 3, characterized in that, It also includes a return valve core (400) that is slidably sleeved on the outside of the cylindrical part (170), the return valve core (400) moving between an open position connecting the outlet section (150) and the return section (160) and a closed position separating the outlet section (150) and the return section (160).

5. The pilot-operated proportional valve according to claim 4, characterized in that, A third channel (162) is provided on the right side of the liquid return section (160) for conveying liquid into the annular gap between the cylindrical part (170) and the liquid return section (160) to drive the liquid return valve core (400) to move. A reversing valve (700) is provided between the third channel (162) and the return port (161) to control the connection between the third channel (162) and the return port (161), or to the pipeline (500).

6. The pilot-operated proportional valve according to claim 1, characterized in that, The pressure relief channel (210) is also provided with a sealing element (212) on its side wall, and the two sealing elements (212) are located on the left and right sides of the balance groove (211), respectively.

7. The pilot-operated proportional valve according to claim 2, characterized in that, The cavity (110) is provided with a guide segment (120), which is located to the left of the control segment (130). The cross-sectional diameter of the guide segment (120) is smaller than that of the control segment (130). The first channel (131) is located adjacent to the guide segment (120) and the control segment (130). The left end of the main valve core (200) is configured as a guide portion (230) that cooperates with the guide segment (120), and the guide portion (230) is slidably inserted into the guide segment (120).

8. The pilot-operated proportional valve according to claim 7, characterized in that, The control pipeline (500) delivers high-pressure liquid to the control section (130), driving the pilot valve core (300) to move a set distance to the left. The pilot valve core (300) repeatedly moves the set distance until the main valve core (200) reaches the preset opening degree.

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