proportional valve

Abstract

The application discloses a proportional valve, which comprises a valve body, a main valve core and a mechanical pilot valve assembly, the valve body has a cavity, the main valve core is movably arranged in the cavity and a main valve core control cavity is formed between the tail of the main valve core and the inner wall of the cavity, the mechanical pilot valve assembly comprises a pilot valve body, a first valve core, a second valve core and a driving assembly, the pilot valve body has a liquid supply channel and a liquid return channel which are communicated with the main valve core control cavity, the first valve core can control the on-off of the liquid supply channel, the second valve core can control the on-off of the liquid return channel, the axes of the first valve core and the second valve core are collinear, and the driving assembly comprises a driving piece, a first driving rod and a second driving rod, the first driving rod is transversely arranged between the first valve core and the second valve core, the second driving rod is rotationally connected with the first driving rod, one end of the second driving rod is rotationally connected with the driving piece, and the other end of the second driving rod is rotationally connected with the main valve core. The proportional valve adopts a mechanical lever feedback form and can realize proportional control of the displacement of the main valve core.

Description

Technical Field

[0001] This invention relates to the field of valve control technology, and more specifically, to a proportional valve. Background Technology

[0002] The coal mining face consists of multiple hydraulic supports arranged sequentially, each connected to the chute by a jack. Besides supporting the roof, these supports also facilitate the movement of the supports and the movement of the chute. For the normal operation of the working face, the hydraulic supports must maintain a certain degree of straightness. During coal mining, the chute serves as the track for the coal mining machine, and it must also maintain a certain degree of straightness to achieve good coal cutting results and ensure the working face is essentially flat.

[0003] Currently, most push hydraulic cylinders use time-controlled two-position three-way switching valves for position control, which is costly and cannot achieve stepless proportional control of the main valve core opening, leaving considerable room for improvement in control accuracy. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to propose a proportional valve that addresses the defects and shortcomings of the prior art. This proportional valve adopts a mechanical lever feedback form, which can realize proportional control of the displacement of the main valve core. The control principle is simple, the control accuracy is high, and the cost is relatively low.

[0005] The proportional valve of this invention includes: a valve body and a main valve core. The valve body has a cavity, and the main valve core is movably disposed within the cavity, with the tail of the main valve core and the inner wall of the cavity forming a main valve core control chamber; a mechanical pilot valve assembly connected to the valve body, the mechanical pilot valve assembly including a pilot valve body, a first valve core, a second valve core, and a drive assembly. The pilot valve body has a supply channel and a return channel communicating with the main valve core control chamber. The first valve core can control the opening and closing of the supply channel, and the second valve core can control the opening and closing of the return channel. The axes of the first valve core and the second valve core are collinear, and the first valve core and the second valve core are spaced apart. The drive assembly includes a drive member, a first drive rod, and a second drive rod. The first drive rod is laterally disposed between the first valve core and the second valve core, and the second drive rod is rotatably connected to the first drive rod. One end of the second drive rod is rotatably connected to the drive member, and the other end is rotatably connected to the tail of the main valve core.

[0006] The proportional valve of this invention includes a pilot valve comprising a first valve core and a second valve core. The first valve core controls the opening and closing of the liquid supply channel, and the second valve core controls the opening and closing of the liquid return channel. The mechanical pilot valve assembly includes a driving member, a first driving rod, and a second driving rod. The first driving rod is laterally disposed between the first and second valve cores. One end of the second driving rod is rotatably connected to the driving member, and the other end is rotatably connected to the main valve core. The first and second driving rods are movably connected. Thus, when the main valve core is opened or closed according to a preset ratio, the driving member can drag the second driving rod to move, thereby driving the first driving rod to move. When the second driving rod moves toward the first valve core, it can drive the first valve core to open the liquid supply channel. The high-pressure liquid supply to the main valve core control chamber can push the main valve core to move and open. Furthermore, the movement of the main valve core can drag the second driving lever to move in the opposite direction to the initial movement direction. This causes the first drive lever to reset. When the first drive lever is fully reset, the first valve core returns to its initial closed state, the liquid supply channel is disconnected, the pressure in the main valve core control chamber remains constant, and the main valve core no longer moves and remains at a fixed opening, i.e., the main valve core is opened according to a preset ratio. When the second drive lever moves toward the second valve core, it can drive the second valve core to open the return liquid channel, and the high-pressure liquid in the main valve control chamber flows out through the return liquid channel. As the pressure in the main valve core control chamber decreases, the main valve core moves toward the closing direction. The movement of the main valve core can drag the second drive lever to move in the opposite direction to the initial movement direction, thereby causing the first drive lever to reset. When the first drive lever is fully reset, the second valve core returns to its initial closed state, the return liquid channel is disconnected, the pressure in the main valve core control chamber remains constant, and the main valve core no longer moves and remains at a fixed opening, i.e., the main valve core is closed according to a preset ratio. Therefore, the mechanical pilot valve assembly of the proportional valve of this application adopts a mechanical lever-type feedback form, which can realize proportional control of the displacement of the main valve core. The control principle is simple, the control accuracy is high, and the cost is relatively low.

[0007] In some embodiments, the connection between the first drive rod and the second drive rod is located at the middle position of the first drive rod, and / or the connection between the first drive rod and the second drive rod is located at the middle position of the second drive rod.

[0008] In some embodiments, the end of the first drive rod is provided with a throttling groove.

[0009] In some embodiments, the pilot valve includes a first pilot valve and a second pilot valve, the first pilot valve having the first valve core and the liquid supply channel, and the second pilot valve including the second valve core and the liquid return channel.

[0010] In some embodiments, the first pilot valve and / or the second pilot valve are ball valves.

[0011] In some embodiments, the drive assembly includes a push rod that passes through the valve body along the length of the main valve core, with one end of the push rod connected to the tail of the main valve core and the other end rotatably connected to the second drive rod.

[0012] In some embodiments, the proportional valve further includes a return valve core and a switching valve. The valve body has an inlet, a return port, and a working port. The main valve core control chamber can control the opening and closing of the inlet and the working port. The return valve core is movably disposed in the valve body to control the opening and closing of the inlet and the return port. The switching valve can control the movement of the return valve.

[0013] In some embodiments, the valve body includes a valve seat, a return valve sleeve, and an inlet valve sleeve connected sequentially along the length of the valve core. The main valve core and the valve seat form the main valve core control chamber. The push rod passes through the valve seat. The return valve core is sandwiched between the return valve sleeve and the main valve core. The return valve sleeve has a first return port, and the return valve sleeve and the valve seat form the return valve core control chamber. The return valve core control chamber communicates with the oil outlet of the switching valve. The inlet valve sleeve has a first inlet port and the working port.

[0014] In some embodiments, the valve body further includes a cone valve seat, which is installed between the return valve sleeve and the inlet valve sleeve; the drive is a linear actuator.

[0015] In some embodiments, when both the supply channel and the return channel are closed, the length of the first drive rod is equal to the distance between the first valve core and the second valve core. Attached Figure Description

[0016] Figure 1 It is a proportional valve according to an embodiment of the present invention, wherein the main valve core is in the closed state.

[0017] Figure 2 It is a proportional valve according to an embodiment of the present invention, wherein the main valve core is in a throttling state.

[0018] Figure 3 This is a schematic diagram of the structure of the first drive rod of the proportional valve according to an embodiment of the present invention.

[0019] Figure label:

[0020] Valve body 1, main valve core 2, return valve core 3, working port 4, first pilot valve 5, second pilot valve 6, first valve core 7, second valve core 8, drive component 9, first drive rod 10, second drive rod 11, switch valve 12, return ball valve push rod 13, inlet ball valve push rod 14, push rod 15, valve seat 16, return valve sleeve 17, inlet valve sleeve 18, cone valve seat 19, return linear actuator 20, throttling groove 21. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] like Figure 1 and Figure 2 As shown, the proportional valve in this embodiment of the invention includes a valve body 1, a main valve core 2, a return valve core 3, a mechanical pilot valve assembly, and a switching valve 12.

[0023] Specifically, valve body 1 has a cavity, and main valve core 2 is movably disposed within the cavity. The tail of main valve core 2 and the inner wall of the cavity form a main valve core control chamber. The outer wall of the cavity has a working port 4, a liquid inlet, and a liquid return port. Main valve core 2 can control the opening and closing of working port 4 and liquid inlet. Liquid return valve core 3 is movably disposed within valve body 1 to control the opening and closing of liquid supply port and liquid return port. Switch valve 12 can control the movement of liquid return valve core 3. It can be understood that when main valve core 2 is open and liquid return valve core 3 is closed, the proportional valve supplies liquid towards the working surface; when main valve core 2 is closed and liquid return valve core 3 is open, the proportional valve returns liquid.

[0024] A mechanical pilot valve assembly is connected to the valve body 1, and the mechanical pilot valve assembly includes a pilot valve body 1, a first valve core 7, a second valve core 8, and a drive assembly. The pilot valve body 1 has a supply channel and a return channel. The first valve core 7 controls the opening and closing of the supply channel, and the second valve core 8 controls the opening and closing of the return channel. Both the supply channel and the return channel are connected to the main valve core control chamber (e.g., ...). Figure 1 and Figure 2 As shown, the liquid supply channel and the liquid return channel are connected to the main valve core control chamber through port K2. The axes of the first valve core 7 and the second valve core 8 are collinear and spaced apart. Preferably, the axes of the first valve core 7 and the second valve core 8 are parallel to the axis of the main valve core 2.

[0025] like Figure 1 and Figure 2As shown, the drive assembly includes a drive member 9, a first drive rod 10, and a second drive rod 11. The first drive rod 10 is laterally disposed between the first valve core 7 and the second valve core 8. The second drive rod 11 is rotatably connected to the first drive rod 10, with one end of the second drive rod 11 rotatably connected to the drive member 9 and the other end rotatably connected to the tail of the main valve core 2. Thus, moving the first drive rod 10 toward the first valve core 7 can push the first valve core 7 to connect the liquid supply channel, and moving the first drive rod 10 toward the second valve core 8 can push the second valve core 8 to connect the liquid return channel. The switching valve 12 is connected to the valve body 1 and can control the movement of the liquid return valve core 3.

[0026] Therefore, for ease of understanding, in conjunction with the appendix Figure 1 and Figure 2 It can be seen that the first valve core 7 and the second valve core 8 are located on the left and right sides of the first drive rod 10, respectively, and the second drive rod 11 is located in the middle of the two. When it is necessary to supply liquid to the working face, the switch valve 12 first controls the return valve core 3 to close, and the drive component 9 drags the second drive rod 11 to the left. Since the bottom of the second drive rod 11 is rotatably connected to the main valve core 2, the second drive rod 11 will deflect to the left around its connection point with the main valve core 2. The second drive rod 11 can drive the first drive rod 10 to move to the left to drive the first valve core 7 to open the liquid supply channel. Then the high pressure liquid flows into the main valve core control chamber through the liquid supply channel. The pressure in the main valve core control chamber increases, which can push the main valve core 2 to move and open to connect the first liquid inlet and the working port 4.

[0027] It is understandable that, such as Figure 2 As shown, when the main valve core 2 moves to the right to open, the main valve core 2 can drag the second drive rod 11 to the right. The second drive rod 11 will rotate to the right around its connection point with the drive component 9. The second drive rod 11 will drive the first drive rod 10 to move to the right until the first drive rod 10 moves back to the initial position. At this point, the first valve core 7 will close, the liquid supply channel will be disconnected, and the pressure in the main valve core control chamber will no longer change. As a result, the main valve core 2 will no longer move and will remain at a fixed opening.

[0028] Furthermore, the proportional control of the main valve core 2 can be achieved through a mechanical lever structure, specifically, as follows: Figure 1 and Figure 2 As shown, the connection point between the first drive rod 10 and the second drive rod 11 can be used as a base point. The upper rod section is connected to the drive component 9, and the lower rod section is connected to the main valve core 2. By allocating the length ratio of the upper rod section and the lower rod section, the stepless proportional control of the main valve core 2 can be achieved.

[0029] For example, when the upper and lower rod segments are of equal length, taking the process of opening the main valve core 2 as an example, if the stroke of the driving component 9 dragging the second driving rod 11 to the left is s, then when the high-pressure liquid in the main valve core control chamber pushes the main valve core 2 to move and open, it will drag the second driving rod 11 to the right. It can be understood that, since the upper and lower rod segments are of equal length, when the main valve core 2 moves for a stroke of s, the second driving rod 11 will return to its initial position, the main valve core control chamber will close, and the main valve core 2 will remain at a fixed opening. That is, at this time, by controlling the dragging stroke of the driving component 9, a "1:1" proportional control of the main valve core 2's movement stroke can be achieved.

[0030] For example, when the ratio of the length of the lower rod segment to the length of the upper rod segment is 2:1, if the stroke of the driving component 9 dragging the second driving rod 11 to the left is L, then the main valve core 2 needs to move to the right by a stroke of 2L before the second driving rod 11 can be reset. That is, by controlling the dragging stroke of the driving component 9, a "1:2" proportional control of the main valve core 2's movement stroke can be achieved. It can be understood that the lengths of the upper and lower rod segments can be any ratio. The driving component can directly control the main valve core to move to the corresponding position according to a set ratio by controlling its own driving stroke of the second driving rod, thereby achieving stepless control of the main valve core's opening degree.

[0031] In other words, the drive unit 9 can control the main valve core 2 to open by driving the first drive rod 10 to move. The opening of the main valve core 2 will feed back to the first drive rod 10 and drive the first drive rod 10 to reset. The drive unit 9 can directly control the main valve core 2 to move to the corresponding position according to the set ratio by controlling its own driving stroke to the second drive rod 11, thereby realizing stepless control of the opening degree of the main valve core 2.

[0032] Furthermore, when it is necessary to control the main valve core 2 to close, the drive component 9 can drag the second drive rod 11 to the right, thereby driving the first drive rod 10 to move to the right. The first drive rod 10 then drives the second valve core 8 to open the return liquid channel, and the high-pressure liquid in the main valve core control chamber can flow out through the return liquid channel. As the pressure in the main valve core control chamber decreases, the main valve core 2 moves back under the action of pressure difference. The mechanical pilot valve assembly can realize stepless proportional control of the closing process of the main valve core 2 through mechanical lever transmission. The control principle can be referred to the opening process of the main valve core 2, and will not be repeated here.

[0033] It is understandable that both the first valve core 7 and the second valve core 8 are equipped with return springs. When the first drive rod 10 is in the initial position, both the first valve core 7 and the second valve core 8 are in the closed state under the action of the return springs. That is, when the first drive rod 10 moves toward one of the valve cores, the other valve core will be in the closed state. The movement of the main valve core 2 will be fed back to the first drive rod 10 and drive the first drive rod 10 to reset. When the main valve core 2 moves to the preset opening position, the first drive lever will be completely reset to the initial position, the main valve core control chamber will be completely sealed, and the main valve core 2 can be maintained at a fixed opening.

[0034] The proportional valve of this invention includes a pilot valve comprising a first valve core 7 and a second valve core 8. The first valve core 7 controls the opening and closing of the liquid supply channel, and the second valve core 8 controls the opening and closing of the liquid return channel. The mechanical pilot valve assembly includes a drive member 9, a first drive rod 10, and a second drive rod 11. The first drive rod 10 is laterally disposed between the first valve core 7 and the second valve core 8. One end of the second drive rod 11 is rotatably connected to the drive member 9, and the other end is rotatably connected to the main valve core 2. The first drive rod 10 and the second drive rod 11 are rotatably connected.

[0035] Therefore, when the main valve core 2 is opened or closed, the driving component 9 can drag the second driving rod 11 to move, thereby driving the first driving rod 10 to move. When the second driving rod 11 moves toward the first valve core 7, it can drive the first valve core 7 to open the liquid supply channel. The liquid supply channel supplies liquid toward the main valve core control chamber, which can push the main valve core 2 to move and open. Moreover, the movement of the main valve core 2 can drag the second driving lever to move in the opposite direction to the initial movement direction, thereby driving the first driving lever to reset. When the first driving rod 10 is fully reset, the first valve core 7 returns to the initial closed state, the liquid supply channel is disconnected, the pressure in the main valve core control chamber is constant, and the main valve core 2 no longer moves and remains fixed. The opening degree, that is, the main valve core 2 is opened according to a preset ratio. When the second drive rod 11 moves toward the second valve core 8, it can drive the second valve core 8 to open the return liquid channel. The high pressure liquid in the main valve control chamber flows out through the return liquid channel. As the pressure in the main valve core control chamber decreases, the main valve core 2 moves toward the closing direction. The movement of the main valve core 2 can drag the second drive rod 11 to move in the opposite direction to the initial movement direction, thereby driving the first drive rod 10 to reset. When the first drive rod 10 is fully reset, the second valve core 8 returns to the initial closed state, the return liquid channel is disconnected, the pressure in the main valve core control chamber is constant, the main valve core 2 no longer moves and remains at a fixed opening degree.

[0036] Therefore, the mechanical pilot valve assembly of the proportional valve in this application adopts a mechanical lever-type feedback form, which can realize stepless control of the opening position of the main valve core 2. The control principle is simple, the control accuracy is high, and the cost is relatively low.

[0037] Additionally, it should be noted that when there is overshoot in the movement of the main valve core 2, the mechanical pilot valve assembly can automatically open the supply or return channel to control the pressure in the main valve core control chamber to maintain a preset value, thereby allowing the main valve core 2 to accurately remain at the preset opening degree. For example, when there is overshoot during the opening process of the main valve core 2, the first drive rod 10, driven by the main valve core 2, will move excessively and drive the second valve core 8 to open the return channel. The high-pressure liquid in the main valve control chamber will then flow out through the return channel. As the pressure in the main valve control chamber decreases, the over-moved main valve core 2 will return a certain stroke until the "excess stroke" is completely offset, the first drive rod 10 is fully reset, the second valve core 8 closes again, and the main valve core 2 can accurately remain at the preset opening degree.

[0038] Preferably, the connection point between the first drive rod 10 and the second drive rod 11 is located at the middle position of the first drive rod 10, and the connection point between the first drive rod 10 and the second drive rod 11 is located at the middle position of the second drive rod 11. Therefore, the linear travel of the drive component 9 can be fed back to the main valve core 2 in a completely "1:1" ratio, resulting in high control precision.

[0039] Preferably, the first drive rod 10 and the second drive rod 11 are ball joints, which eliminates the adverse effects of the main valve core 2 rotating along its own axis during movement on the feedback mechanism.

[0040] Optionally, such as Figure 1 and Figure 2 As shown, the pilot valve includes a first pilot valve 5 and a second pilot valve 6. The first pilot valve 5 has a first valve core 7 and a liquid supply channel, and the second pilot valve 6 includes a second valve core 8 and the return channel. That is, two independent pilot valves are used to control the opening and closing of the liquid supply channel and the return channel respectively, which is convenient for layout, and the layout position can be adaptively adjusted according to the length of the first drive rod 10.

[0041] Preferably, such as Figure 1 and Figure 2 As shown, the first pilot valve 5 and / or the second pilot valve 6 are ball valves. It is understood that ball valves have good sealing performance. When the ball valve is closed, the main valve core control chamber is completely sealed, and the position of the main valve core 2 can be reliably maintained. Even if the main valve core 2 is disturbed by external forces, the main valve core 2 also has a certain degree of anti-disturbance capability.

[0042] In some embodiments, such as Figure 1 and Figure 2 As shown, the drive assembly includes a push rod 15, which passes through the valve body 1 along the length of the main valve core 2. One end of the push rod 15 is connected to the tail of the main valve core 2, and the other end is rotatably connected to the second drive rod 11.

[0043] In some embodiments, such as Figure 1 and Figure 2As shown, the valve body 1 includes a valve seat 16, a return valve sleeve 17, and an inlet valve sleeve 18 connected sequentially along the length of the valve core. The main valve core 2 and the valve seat 16 form a main valve core control chamber. A push rod 15 passes through the valve seat 16. The return valve core is sandwiched between the return valve sleeve 17 and the main valve core 2. The return valve sleeve 17 has a first return port, and the return valve sleeve 17 and the valve seat 16 form a return valve core 3 control chamber. The return valve core 3 control chamber is connected to the outlet of the switching valve 12 (e.g., ...). Figure 1 As shown, the outlet of the switching valve 12 is connected to the control chamber of the return valve core 3 through port K1, and the inlet valve sleeve 18 has a first inlet and a working port 4.

[0044] like Figure 1 As shown, the switching valve 12 includes a return linear actuator 20, a return ball valve push rod 13 connected to its drive end, and an inlet ball valve push rod 14 connected to the return ball valve push rod 13. It should be noted that before the main valve core 2 opens, the switching valve 12 needs to control the return valve core to close. Specifically, as shown... Figure 1 As shown, when the main valve core 2 is in the closed state, the return fluid linear actuator 20 closes the return fluid ball valve through the return fluid ball valve push rod 13 and drives the inlet fluid ball valve push rod 14 to open the inlet fluid ball valve. The high pressure fluid is supplied to the return fluid valve core control chamber through the supply port of the switch valve 12. The return fluid valve core closes the first return fluid port under the pressure, and then the main valve core 2 is opened by the mechanical pilot valve core assembly.

[0045] Preferably, such as Figure 1 and Figure 2 As shown, the valve body 1 also includes a cone valve seat 19, which is installed between the return valve sleeve 17 and the inlet valve sleeve 18.

[0046] Preferably, the driving element 9 is a linear actuator.

[0047] Preferably, the linear actuator can be any electromechanical converter that can achieve proportional displacement output, such as a linear motor, electric push rod 15, proportional electromagnet, or motor plus ball screw.

[0048] Preferably, when both the supply and return channels are closed, the length of the first drive rod 10 is equal to the distance between the first valve core 7 and the second valve core 8. Therefore, the movement of the first drive rod 10 can sensitively control the opening of either the first valve core 7 or the second valve core 8, resulting in high control precision.

[0049] Preferably, such as Figure 3 As shown, the end of the first drive rod 10 is provided with a throttling groove 21.

[0050] Preferably, the throttling grooves 21 are multiple components arranged circumferentially at intervals around the first drive rods 10. Therefore, the throttling grooves 21 can reduce the instantaneous pressure surge when the pilot ball valve opens, making the opening or closing process of the ball valve smoother.

[0051] Optionally, the throttling groove 21 extends along the length of the first drive rod 10. As the pilot valve core closes, the first drive rod 10 gradually moves back, the effective throttling length of the throttling groove 21 gradually increases, the closing process of the pilot valve core gradually slows down, and the opening and closing process is smooth.

[0052] Optionally, the throttling groove 21 can be of different shapes such as triangle, semicircle, or rectangle, and there can be multiple grooves, as long as they are evenly distributed in the circumferential direction.

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0054] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0055] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0056] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0057] In this invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A proportional valve, characterized in that, include: The valve body has a cavity, and the main valve core is movably disposed in the cavity, with the tail of the main valve core and the inner wall of the cavity forming a main valve core control cavity. A mechanical pilot valve assembly is connected to the valve body and includes a pilot valve body and a drive assembly. The pilot valve body has a supply channel and a return channel communicating with the main valve core control chamber. The pilot valve body includes a first valve core and a second valve core. The first valve core can control the opening and closing of the supply channel, and the second valve core can control the opening and closing of the return channel. The axes of the first valve core and the second valve core are collinear, and the first valve core and the second valve core are spaced apart. The drive assembly includes a drive member, a first drive rod, and a second drive rod. The first drive rod is laterally disposed between the first valve core and the second valve core. The second drive rod is movably connected to the first drive rod, and one end of the second drive rod is rotatably connected to the drive member, while the other end is rotatably connected to the tail of the main valve core. It also includes a return valve core and a switching valve. The valve body has an inlet, a return port and a working port. The main valve core can control the opening and closing of the inlet and the working port. The return valve core is movably disposed in the valve body to control the opening and closing of the inlet and the return port. The switching valve can control the movement of the return valve core.

2. The proportional valve according to claim 1, characterized in that, The connection point between the first drive rod and the second drive rod is located in the middle of the first drive rod, and / or the connection point between the first drive rod and the second drive rod is located in the middle of the second drive rod.

3. The proportional valve according to claim 1, characterized in that, The end of the first drive rod is provided with a throttling groove.

4. The proportional valve according to claim 1, characterized in that, The pilot valve body includes a first pilot valve and a second pilot valve. The first pilot valve has a first valve core and the liquid supply channel, and the second pilot valve includes a second valve core and the liquid return channel.

5. The proportional valve according to claim 4, characterized in that, The first pilot valve and / or the second pilot valve are ball valves.

6. The proportional valve according to claim 1, characterized in that, The drive assembly includes a push rod that passes through the valve body along the length of the main valve core, with one end of the push rod connected to the tail of the main valve core and the other end rotatably connected to the second drive rod.

7. The proportional valve according to claim 6, characterized in that, The valve body includes a valve seat, a return valve sleeve, and an inlet valve sleeve connected sequentially along the length of the valve core. The main valve core and the valve seat form the main valve core control chamber. The push rod passes through the valve seat. The return valve core is sandwiched between the return valve sleeve and the main valve core. The return valve sleeve has the return port, and the return valve sleeve and the valve seat form the return valve core control chamber. The return valve core control chamber communicates with the oil outlet of the switching valve. The inlet valve sleeve has the inlet port and the working port.

8. The proportional valve according to claim 7, characterized in that, The valve body also includes a cone valve seat, which is installed between the return valve sleeve and the inlet valve sleeve; The driving component is a linear actuator.

9. The proportional valve according to any one of claims 1-8, characterized in that, When both the supply channel and the return channel are closed, the length of the first drive rod is equal to the distance between the first valve core and the second valve core.

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