Pilot follow-up proportional valve

Abstract

Disclosed is a pilot follow-up proportional valve, comprising: a valve sleeve (100), wherein the valve sleeve is provided with an accommodating cavity (110) running through two ends thereof along the axis thereof, the accommodating cavity comprising a control section (130), a liquid intake section (140) and a liquid output section (150), the liquid intake section and the liquid output section being respectively provided with a liquid inlet (141) and a liquid outlet (151); and a main valve core (200), which moves between an open position, in which the liquid intake section is in communication with the liquid output section, and a closed position, in which the liquid intake section is separated from the liquid output section, the main valve core being provided with a pressure relief passage (210) running through two ends thereof along the axis thereof. The valve sleeve is provided with a first passage (131) and a second passage (142) which are in communication with the control section so as to drive the main valve core to move; the main valve core is provided with a first through hole (220) which communicates the pressure relief passage with the control section in the radial direction; and the pressure relief passage is provided with a pilot valve core (300) which moves in the axial direction thereof and is used to control the on-off state between the first through hole and the pressure relief passage.

Description

Pilot follow-up proportional valve

[0001] Cross-reference to Related Applications

[0002] This application claims priority to Chinese Patent Application No. 2025101360178, filed on February 7, 2025, entitled "Pilot follow-up proportional valve", which is incorporated by reference herein in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of hydraulic valves, in particular to a pilot follow-up proportional valve. BACKGROUND

[0004] At present, the pilot follow-up proportional valve can realize proportional control of the valve opening, but the method adopted is that the valve sleeve is arranged in the main valve core sleeve to form a control section at the left end and the right end of the main valve core, the pilot circuit communicates the two control sections, and the pressure of the liquid entering the two control sections is adjusted through the pressure reducing valve arranged in the pilot circuit, so as to control the displacement of the main valve core and realize proportional control of the valve opening.

[0005] However, this method needs to maintain the pressure balance of the two control sections, and the unstable phenomenon of valve core oscillation is easy to occur in the use process, the control difficulty is high, not only an additional pressure reducing valve is needed, but also the machining and cooperation of the parts need high precision, the machining difficulty is large, which greatly increases the cost. SUMMARY

[0006] The present application aims to at least solve one of the technical problems in the related art. To this end, the present application provides a pilot follow-up proportional valve to simplify the structure of the pilot proportional valve, improve the stability of the valve core movement, reduce the control difficulty, and ensure the consistency of the opening and closing characteristics.

[0007] The present application provides a pilot follow-up proportional valve, comprising:

[0008] a valve sleeve, the valve sleeve is provided with a cavity through both ends 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;

[0009] a main valve core, moving between an open position communicating the liquid inlet section and the liquid outlet section and a closed position isolating the liquid inlet section and the liquid outlet section, the main valve core is provided with a pressure relief hole along its axis;

[0010] The valve sleeve is provided with a first hole and a second hole which communicate with the control section to drive the main valve core to move; the main valve core is provided with a first through hole which communicates the pressure relief hole and the control section in the radial direction; the pressure relief hole is provided with a pilot valve core which moves along the axial direction to control the opening and closing state of the first through hole and the pressure relief hole.

[0011] According to the pilot follow-up type proportional valve provided by the application, the driving device is connected with the pilot valve core and fixed at the left end of the cavity, and is used to drive the pilot valve core to move relative to the pressure relief hole.

[0012] The pilot valve core is provided with a second through hole which extends from the end surface to the side wall, and the second through hole is located at the right side of the first through hole, and is used to make the pilot valve core have an initial position which blocks the first through hole and the pressure relief hole.

[0013] According to the pilot follow-up type proportional valve provided by the application, the pressure relief hole is provided with a balance groove which extends along the circumference of the side wall, and the first through hole extends through the bottom surface of the balance groove to the control section.

[0014] 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.

[0015] According to the pilot follow-up type proportional valve provided by the application, the main valve core is provided with a control part which slides in the control section, the valve sleeve is provided with a first hole and a second hole which are used to deliver liquid to the control section to drive the main valve core to move.

[0016] When the liquid flow rate entering the control section from the first hole is greater than the liquid flow rate discharged from the control section through the second through hole, the main valve core moves to the right; or when the liquid flow rate entering the control section from the first hole is less than the liquid flow rate discharged from the control section through the second through hole, the main valve core moves to the left.

[0017] The first hole communicates from the outside of the valve sleeve to the left side of the control section, the second hole communicates from the liquid inlet to the right side of the control section, and the pipeline communicates with the first hole and the second hole.

[0018] According to the pilot follow-up type proportional valve provided by the application, the right end of the cavity is further provided with a liquid return section which has a liquid return port, the valve sleeve is provided with a cylindrical part in the liquid return section, the cylindrical part has an annular space with the inner wall of the liquid return section, and the right end of the main valve core is slidingly inserted into the cylindrical part.

[0019] The pilot follow-up type proportional valve further comprises a liquid return valve core slidingly sleeved outside the cylindrical portion, and the liquid return valve core moves between an open position for connecting the liquid outlet section and the liquid return section and a closed position for separating the liquid outlet section and the liquid return section.

[0020] The pilot follow-up type proportional valve further comprises a third channel arranged on the right side of the liquid return section and used for conveying liquid into an annular space between the cylindrical portion and the liquid return section to drive the liquid return valve core to move.

[0021] The third channel and the liquid return port are provided with a reversing valve used for controlling the third channel to be connected with the liquid return port or the pipeline.

[0022] The pilot follow-up type proportional valve further comprises two sealing members arranged on the left side and the right side of the balance groove respectively.

[0023] The pilot follow-up type proportional valve further comprises a guide section arranged on the left side of the control section, wherein the guide section has a smaller cross-sectional diameter than the control section, and the first channel is arranged adjacent to the guide section and the control section.

[0024] The left end of the main valve core is provided with a guide portion matched with the guide section, and the guide portion is slidingly inserted into the guide section.

[0025] The pipeline is controlled to convey high-pressure liquid to the control section, and the pilot valve core is driven to move leftward by a set distance, and the above movement process is repeated until the main valve core reaches a preset opening degree.

[0026] The one or more technical solutions provided in the application have at least one of the following technical effects:

[0027] The pilot valve core is slidingly connected with the control section, and then the liquid in the control section is discharged through the pressure relief channel, so that the opening force acting on the main valve core is greater than the closing force, and the main valve core is slidingly connected with the liquid inlet section and the liquid outlet section. When the pilot follow-up type proportional valve is in an open state, the slight movement of the pilot valve core changes the pressure of the control section, and then changes the force balance state of the main valve core, so that the main valve core moves almost simultaneously with the pilot valve core, thereby improving the response speed of the pilot follow-up type proportional valve, and ensuring that the pilot follow-up type proportional valve has high control accuracy, stability and consistency.

[0028] In addition to the technical problems solved by the application, the technical features of the technical solutions and the advantages brought by the technical features, other technical features of the application and the advantages brought by the technical features will be further described with reference to the drawings or can be known by practicing the application. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the drawings needed to be used in the embodiments or the related art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0030] Fig. 1 is a schematic diagram of a pilot follow-up proportional valve in an initial state (the inlet of the main valve core is closed) according to an embodiment of the application.

[0031] Fig. 2 is a schematic diagram of the pilot follow-up proportional valve when the pilot valve core moves to a critical state (the inlet of the main valve core is about to be opened) according to an embodiment of the application.

[0032] Fig. 3 is a schematic diagram of the pilot follow-up proportional valve when the pilot valve core moves to a state that the first through hole and the second through hole are communicated (the inlet of the main valve core is in the process of being opened) according to an embodiment of the application.

[0033] Fig. 4 is a schematic diagram of the pilot follow-up proportional valve when the pilot valve core moves to an equilibrium state (the main valve core stops moving) according to an embodiment of the application.

[0034] Reference signs: 100, valve sleeve; 110, cavity; 120, guide section; 130, control section; 131, first hole; 140, inlet section; 141, inlet; 142, second hole; 150, outlet section; 151, outlet; 160, return section; 161, return; 162, third hole; 170, cylindrical part; 200, main valve core; 210, pressure relief hole; 211, balance groove; 212, sealing element; 220, first through hole; 230, guide part; 240, control part; 300, pilot valve core; 310, second through hole; 400, return valve core; 500, pipeline; 600, driving device; 700, reversing valve; 800, throttle valve. DETAILED DESCRIPTION

[0035] In order to make the purposes, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly described below with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0036] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the embodiments of the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0037] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0038] In the embodiments of the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or it can only mean that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or it can only mean that the horizontal height of the first feature is less than that of the second feature.

[0039] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0040] In the present application, the pilot proportional valve refers to a device that combines the functions of a pilot valve and a main valve, can adjust the flow of fluid or the pressure of fluid according to the input signal (usually an electrical signal), so as to more accurately control the flow of the supplied fluid, and realize continuous and accurate adjustment of components such as hydraulic cylinders and hydraulic supports.

[0041] As shown in FIG. 1, in the embodiments of the present application, a pilot follow-up type proportional valve is introduced. The pilot follow-up type proportional valve mainly comprises a valve sleeve 100, a main valve core 200, a pilot valve core 300, a return valve core 400, and a driving device 600.

[0042] Specifically, the valve sleeve 100 is provided with a cavity 110 penetrating through both ends thereof along the axis thereof. The cavity 110 is sequentially provided with a guide segment 120, a control segment 130, a liquid inlet segment 140, a liquid outlet segment 150, and a return liquid segment 160 from left to right. The liquid inlet segment 140, the liquid outlet segment 150, and the return liquid segment 160 are respectively provided with a liquid inlet 141, a liquid outlet 151, and a return liquid port 161.

[0043] The main valve core 200 moves between an open position connecting the liquid inlet segment 140 and the liquid outlet segment 150 and a closed position separating the liquid inlet segment 140 and the liquid outlet segment 150. The main valve core 200 is provided with a pressure relief hole 210 extending along the axis thereof.

[0044] Furthermore, the valve sleeve 100 is provided with a first hole 131 and a second hole 142 in communication with the control segment 130 to drive the main valve core 200 to move. The outside of the valve sleeve 100 is provided with a pipeline 500 in communication with the first hole 131 and the liquid inlet 141. The pipeline 500 is in communication with the first hole 131 and the second hole 142, respectively. The main valve core 200 is provided with a first through hole 220. The first through hole 220 extends along the radial direction of 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 segment 130 and the pressure relief hole 210.

[0045] In addition, the pressure relief channel 210 is provided with a pilot spool 300 which is matched with the pressure relief channel 210 and axially slides along the pressure relief channel 210. The left end of the pilot spool 300 protrudes from the left end of the pressure relief channel 210, and the right end of the pilot spool 300 is embedded in the pressure relief channel 210. The right end of the pilot spool 300 can reciprocate on the left side and the right side of the first through hole 220, and is used to control the on-off state of the first through hole 220 and the pressure relief channel 210.

[0046] Further, the main spool 200 is provided with a pressure relief channel 210 which penetrates through both ends of the main spool 200 along the axis of the main spool 200.

[0047] In the embodiment, the sliding of the pilot spool 300 can make the first through hole 220 communicate with the control section 130, and then the liquid in the control section 130 is discharged through the pressure relief channel 210, so that the opening force received by the main spool 200 is greater than the closing force received by the main spool 200, and the main spool 200 slides to the left to communicate the inlet section 140 and the outlet section 150. When the pilot-following proportional valve is in the opening state, the slight movement of the pilot spool 300 can change the pressure of the control section 130, and then change the force balance state of the main spool 200, so that the main spool 200 moves almost simultaneously with the pilot spool 300, which improves the response speed of the pilot-following proportional valve, and ensures that the pilot-following proportional valve has high control accuracy, stability and consistency.

[0048] On the basis of the above-mentioned embodiment, another embodiment of the present application introduces a pilot-following proportional valve.

[0049] In order to accurately control the movement distance of the pilot spool 300 in the pressure relief channel 210, a driving device 600 is arranged at the left end of the valve sleeve 100. The driving device 600 is connected with the pilot spool 300, and is used to drive the pilot spool 300 to move relative to the pressure relief channel 210. Preferably, the driving device 600 is fixed at the left end of the container cavity 110 and is arranged along the central axis of the container cavity 110.

[0050] Further, the right end of the pilot spool 300 is provided with a second through hole 310, which is used to smoothly slide the pilot spool 300 in the pressure relief channel. The second through hole 310 extends from the right end face of the pilot spool 300 to the side wall of the pilot spool 300. When the pilot spool 300 is in the initial position, the second through hole 310 is located on the right side of the first through hole 220, which is used to block the first through hole 220 and the pressure relief channel 210.

[0051] Further, the driving device 600 is rigidly coupled with the pilot spool 300. When the pilot spool 300 is in the position shown in Fig. 1, the second through hole 310 of the pilot spool 300 is in a state of being isolated from the control section 130 on the left side of the main spool 200, and the pressure of the liquid in the control section 130 is equal to the inlet pressure of the pipeline 500. The part of the control section 130 on the right side of the main spool 200 is in a state of being communicated with the inlet 141 through the second hole 142, and the pressure of the liquid in the control section 130 is also equal to the inlet pressure of the pipeline 500.

[0052] However, the annular area of the control section 130 on the left side of the main spool 200 is larger than the area of the control section 130 on the right side of the main spool 200, so the resultant force acting on the main spool 200 is to the right. The main spool 200 is sealed by the conical surface abutting the cavity 110, so the inlet 141 and the outlet 151 are isolated.

[0053] Further, by driving the pilot spool 300 to slide in the pressure relief hole 210 through the driving device 600, the position of the main spool 200 can be changed to follow the position of the pilot spool 300, i.e. the main spool 200 moves following the pilot spool 300.

[0054] For example, the driving device 600 drives the pilot spool 300 to move to the left by a certain distance. When the second through hole 310 of the pilot spool 300 is communicated with the first through hole 220, the pressure relief hole 210 is communicated with the control section 130 on the left side of the main spool 200. At this time, the liquid in the control section 130 on the left side of the main spool 200 is communicated with the return port 161 through the first through hole 220, the second through hole 310 and the pressure relief hole 210. The pressure in the control section 130 on the left side of the main spool 200 is reduced, and at this time the pipeline 500 continuously supplies high-pressure liquid to the control section 130 on the left side of the main spool 200 through the first hole 131.

[0055] However, the pipeline 500 in communication with the first hole 131 is in series with a throttle valve 800. Since the throttle valve 800 has a certain pressure drop effect, the greater the flow, the greater the pressure drop. At the same time, the pressure of 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 is reduced to a certain value, due to the pressure difference on both sides, the liquid will drive the main valve core 200 to move to the left until the second through hole 310 of the pilot valve core 300 is forced to be disconnected with the first through hole 220, and the movement of the main valve core 200 stops. At this time, the main valve core 200 has completed the movement following the pilot valve core 300. And the inlet 141 and the outlet 151 are in communication, and keep a certain opening. If the opening between the inlet 141 and the outlet 151 is increased to increase the flow, the control driving device 600 will drive the pilot valve core 300 to move to the left by a certain distance, and the main valve core 200 will follow. Repeating the above steps can complete the opening operation of the main valve core 200.

[0056] Therefore, by controlling the displacement of the pilot valve core 300 through the driving device 600, the displacement of the main valve core 200 can be controlled, the precise and continuous control of the opening of the main valve core 200 is realized, the installation of the valve core displacement sensor is avoided, the overall structure of the pilot proportional valve is greatly simplified, the processing and manufacturing of the pilot proportional valve are easier, and the cost is lower.

[0057] Further, the effective cross-sectional area of the second through hole 310 is greater than the effective throttling area of the throttle valve 800, so that the liquid discharge capacity of the pilot valve core 300 is greater than the liquid inlet capacity of the throttle valve 800.

[0058] On the basis of the above embodiment, another embodiment of the present application introduces a pilot follow-up type proportional valve.

[0059] In order to make the main valve core 200 have consistent starting characteristics in the control process, the main valve core 200 is balanced. Specifically, the pressure relief hole 210 is provided with a balance groove 211 extending along the circumferential direction of the side wall. The first through hole 220 extends through the control section 130 from the bottom surface of the balance groove 211.

[0060] 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. In this way, when the pilot valve core 300 is controlled to slide in the pressure relief hole 210, there is a certain buffer space between the second through hole 310 of the pilot valve core 300 and the first through hole 220, avoiding the sharp fluctuation of the on-off of the second through hole 310 and the first through hole 220, and improving the reliability and stability of the pilot proportional valve.

[0061] On the basis of the above embodiment, another embodiment of the present application introduces a pilot follow-type proportional valve.

[0062] The main valve core 200 is provided with a control part 240 sliding in the control section 130. The outer part of the valve sleeve 100 is provided with a pipeline 500 communicating the first hole 131 and the liquid inlet 141, for delivering liquid into the control section 130 to drive the main valve core 200 to move.

[0063] When the liquid flow into the control section 130 from the first hole 131 is greater than the liquid flow out of the control section 130 from the second through hole 310, the main valve core 200 moves to the right.

[0064] Or, when the liquid flow into the control section 130 from the first hole 131 is less than the liquid flow out of the control section 130 from the second through hole 310, the main valve core 200 moves to the left.

[0065] The first hole 131 communicates from the outside of the valve sleeve 100 to the left side of the control section 130. The second hole 142 communicates from the liquid inlet 141 to the right side of the control section 130. The pipeline 500 communicates with the first hole 131 and the second hole 142.

[0066] As shown in FIG. 1, in the initial state of the pilot follow-up proportional valve, the reversing valve 700 is not powered, the high-pressure liquid is disconnected from the third hole 162, and at this time the liquid return valve core 400 is located at the right end of the liquid return section 160, and the liquid outlet is connected with the liquid return port.

[0067] As shown in FIG. 2, the reversing valve 700 is powered, the high-pressure liquid is connected with the third hole 162, and under the action of the high-pressure liquid, the liquid return valve core 400 moves to the left end of the liquid return section 160, at this time the liquid outlet is disconnected from the liquid return port. Under the condition of keeping the reversing valve 700 powered, the driving device 600 drives the pilot valve core 300 to move to the left side, and when the pilot valve core 300 moves to the first through hole 220 and is about to be connected with the second through hole 310, it is the critical state.

[0068] In the critical state, the pilot valve core 300 continues to move to the left, and the control section 130 is connected with the second through hole 310, the pressure in the control section 130 is reduced, the force balance is broken, and under the action of the unbalanced force, the main valve core 200 starts to move to the left side.

[0069] As shown in Fig. 4, assuming that the pilot spool 300 remains unchanged after moving to a certain position, as the follow-up movement of the main spool 200 proceeds, when the main spool 200 moves to the position shown in Fig. 4, the second through hole 310 on the pilot spool 300 is in a semi-open semi-closed state, the main spool 200 rebalances and remains unchanged. In this balanced working state, as long as the pilot spool 300 moves to the left, the force balance on both sides of the control part 240 of the main spool 200 will be broken, and the main spool 200 will follow the pilot spool 300 to move to the left until it moves again to the position where the second through hole 310 on the pilot spool 300 is in a semi-open semi-closed state, and then it is balanced again.

[0070] Similarly, in this balanced working state, as long as the pilot spool 300 moves to the right, the force balance on both sides of the control part 240 of the main spool 200 will be broken, and the pressure on the left side of the control part 240 of the main spool 200 will rise, driving the main spool 200 to move to the right until it moves again to the position where the second through hole 310 on the pilot spool 300 is in a semi-open semi-closed state, and then it is balanced again.

[0071] When the pilot spool 300 moves to the right all the time, the main valve port is continuously closed, and when the main spool 200 just contacts the valve sleeve to close the upper part, at this time the second through hole 310 on the pilot spool 300 is still in a semi-open semi-closed balanced state. In order to reliably seal the main valve port, the pilot spool 300 needs to continue to move to the right until the control segment 130 is not in communication with the second through hole 310, at this time the pressure on the left side of the control part 240 of the main spool 200 rises, ensuring that the main spool 200 is tightly sealed on the tapered surface of the valve sleeve 100.

[0072] On the basis of the above-mentioned embodiment, another embodiment of the present application introduces a pilot follow-up type proportional valve.

[0073] The right end of the cavity 110 is provided with a liquid return segment 160 having a liquid return port 161. The valve sleeve 100 is provided with a cylindrical portion 170 at the liquid return segment 160. The cylindrical portion 170 and the inner wall of the liquid return segment 160 have an annular space therebetween. The right end of the main spool 200 is slidingly inserted into the cylindrical portion 170.

[0074] Further, the pilot follow-up type proportional valve further comprises a liquid return spool 400 slidingly sleeved outside the cylindrical portion 170. The liquid return spool 400 moves between an open position in communication with the liquid outlet segment 150 and the liquid return segment 160 and a closed position isolating the liquid outlet segment 150 and the liquid return segment 160.

[0075] The right side of the liquid return segment 160 is provided with a third hole 162 for delivering liquid into the annular space between the cylindrical portion 170 and the liquid return segment 160 to drive the liquid return spool 400 to move.

[0076] The third hole 162 and the return port 161 are provided with a reversing valve 700 for controlling the communication between the third hole 162 and the return port 161 or the pipeline 500.

[0077] Specifically, the reversing valve 700 is an electromagnetic switch valve. When the electromagnetic switch valve is in a de-energized position as shown in FIG. 1, the third hole 162 on the right side of the return valve core 400 is in communication with the return port 161 through the electromagnetic switch valve. At this time, the outlet port 151 and the return port 161 are in communication. In addition, the pilot-following proportional valve in the present application is a two-position three-way structure. It is provided with three working interfaces, which are the inlet port P, the outlet port A and the return port R. The initial state is that the inlet port 141 is disconnected from the outlet port 151, and the outlet port 151 is connected to the return port 161.

[0078] The outlet port 151 is usually connected to the working chamber of the hydraulic cylinder. When the hydraulic cylinder needs to be extended, the inlet port 141 needs to be connected to the outlet port 151, and the outlet port 151 needs to be disconnected from the return port 161.

[0079] At this time, the working process of the pilot-following proportional valve is as follows: first, close the return valve core 400, that is, energize the electromagnetic switch valve, and the high-pressure liquid in the pipeline 500 enters the right side of the return valve core 400 through the electromagnetic switch valve and the third hole 162, pushing the return valve core 400 to move left to disconnect the connection between the outlet section 150 and the return section 160. That is, to cut off the outlet port 151 and the return port 161.

[0080] Then, the driving device 600 drives the pilot valve core 300 to move left by a set distance. When the second through hole 310 of the pilot valve core 300 is in communication with the first through hole 220, the relief hole 210 is in communication 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 is in communication with the return port 161 through the first through hole 220, the second through hole 310 and the relief hole 210. The pressure in the control section 130 on the left side of the main valve core 200 is reduced, and at this time the pipeline 500 will continuously supply high-pressure liquid to the control section 130 on the left side of the main valve core 200.

[0081] However, the pipeline 500 is in series with the first hole 131 and has a throttle valve 800. Since the throttle valve 800 has a certain pressure drop, the greater the flow, the greater the pressure drop. At the same time, the pressure of 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 is reduced to a certain value, the liquid will drive the main valve core 200 to move to the left due to the pressure difference on both sides, and the main valve core 200 will stop moving when the second through hole 310 of the pilot valve core 300 is forced to be disconnected from the first through hole 220. At this time, the main valve core 200 has completed the movement following the pilot valve core 300. And the inlet 141 and the outlet 151 are connected, and the opening degree is kept constant. If the opening degree between the inlet 141 and the outlet 151 is increased to increase the flow, the control driving device 600 will drive the pilot valve core 300 to move to the left by a certain distance, and the main valve core 200 will follow. Repeat the above steps to complete the opening operation of the main valve core 200.

[0082] In this embodiment, the control of the main valve core 200 and the return valve core 400 is divided, and is controlled by a driving device 600 and a two-position three-way electromagnetic on-off valve respectively, that is, the reliability of the structure is ensured, and the precise control of the position of the main valve core 200 is realized. Moreover, only the pressure of the control section 130 at the left end of the pilot proportional valve needs to be controlled to realize the movement control of the main valve core 200, which greatly simplifies the structure of the valve sleeve 100 and reduces the machining difficulty and cost of the pilot proportional valve.

[0083] On the basis of the above embodiment, another embodiment of the present application introduces a pilot following type proportional valve.

[0084] In order to improve the sealing performance between the relative movement surface of the pilot valve core 300 and the main valve core 200, a sealing member 212 is further arranged on the side wall of the pressure relief hole 210. The two sealing members 212 are respectively located on the left side and the right side of the balance groove 211.

[0085] Further, the cavity 110 is provided with a guide section 120. The guide section 120 is located on the left side of the control section 130. The cross-sectional diameter of the guide section 120 is smaller than that of the control section 130. The first hole 131 is located adjacent to the guide section 120 and the control section 130.

[0086] The left end of the main valve core 200 is provided with a guide part 230 matched with the guide section 120. The guide part 230 is slidingly inserted into the guide section 120.

[0087] In this embodiment, the pilot valve core 300 is provided in the form of a sliding valve with a sealing structure, which is applicable to hydraulic systems based on water-based medium, such as underground coal mine application scenarios, and is also applicable to oil-based hydraulic products, while reducing the friction between the pilot valve core 300 and the main valve core 200, and further reducing the driving power required by the driving device 600.

[0088] On the basis of the above-mentioned embodiments, another embodiment of the present application introduces a pilot follow-up type proportional valve.

[0089] The correlation parameters of the opening degree of the main valve core 200 and the displacement amount of the pilot valve core 300 are set. The control pipeline 500 delivers high-pressure liquid to the control section 130. The pilot valve core 300 is driven to move left by a set distance. The above-mentioned movement process is repeated until the main valve core 200 reaches the preset opening degree.

[0090] Specifically, first, the correlation parameters of the opening degree of the main valve core 200 and the displacement amount of the pilot valve core 300 are preset, and a linear relationship of the positive correlation between the opening degree of the main valve core 200 and the displacement amount of the pilot valve core 300 is obtained.

[0091] Then, the driving device 600 is controlled to drive the pilot valve core 300 to move according to the set distance by supplying high-pressure liquid to the pilot proportional valve through the pipeline 500. The specific steps are as follows: the return liquid valve core 400 is closed, the high-pressure liquid of the pipeline 500 enters the right side of the return liquid valve core 400 through the electromagnetic on-off valve and the third hole 162, and pushes the return liquid valve core 400 to move left to disconnect the connection between the liquid outlet section 150 and the return liquid section 160; the driving device 600 drives the pilot valve core 300 to move left by a set distance, and the liquid drives the main valve core 200 to move left to complete the movement following the pilot valve core 300.

[0092] Finally, if the opening degree between the liquid inlet 141 and the liquid outlet 151 is increased, the driving device 600 is controlled to drive the pilot valve core 300 to move left by a certain distance again, and the main valve core 200 moves following the pilot valve core 300. This step is repeated until the set opening degree is reached.

[0093] Finally, it should be pointed out that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0094] The above only describes preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pilot-operated proportional valve, comprising: 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).

2. The pilot-operated proportional valve according to claim 1, wherein, 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).

3. The pilot-operated proportional valve according to claim 2, wherein, 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).

4. The pilot-operated proportional valve according to any one of claims 1-3, wherein, 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).

5. The pilot-operated proportional valve according to claim 4, wherein, 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).

6. The pilot-operated proportional valve according to claim 5, wherein, 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).

7. The pilot-operated proportional valve according to claim 6, wherein, 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. 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).

8. The pilot-operated proportional valve according to claim 3, wherein, 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.

9. The pilot-operated proportional valve according to claim 4, wherein, 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).

10. The pilot-operated proportional valve according to claim 9, wherein, The control pipeline (500) is used to deliver high-pressure liquid to the control section (130), driving the pilot valve core (300) to move a set distance to the left. The above moving process is repeated until the main valve core (200) reaches the preset opening degree.

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