Three-stage electro-hydraulic proportional control valve

Abstract

The present disclosure relates to the technical field of electro-hydraulic control, and a three-stage electro-hydraulic proportional control valve, wherein a main valve component comprises a hydraulic control main valve core, a pilot component comprises two first pilot mechanisms which are identical in structure and connected to the same pressure source, and two second pilot mechanisms which are coaxially arranged at two ends of the hydraulic control main valve core; two ends of each second pilot mechanism are respectively provided with a first cavity and a sixth cavity, the first cavity and the sixth cavity are respectively connected to liquid outlets of the two first pilot mechanisms, two ends of the hydraulic control main valve core are respectively provided with a third cavity and a fourth cavity, the third cavity is in communication with the liquid outlet of the second pilot mechanism I, the liquid inlet of the third cavity is in communication with a main liquid inlet, and the third cavity is also in communication with the liquid inlet of the second pilot mechanism II. By controlling the displacement and speed of the two second pilot mechanisms, the opening amount, speed, flow size and continuous smooth control of the hydraulic control main valve core when opening or closing are realized.

Description

Technical Field

[0001] This disclosure relates to the field of electro-hydraulic control technology, and in particular to a three-stage electro-hydraulic proportional control valve. Background Technology

[0002] Currently, all hydraulic cylinders in coal mine hydraulic supports are controlled using high-flow-rate water-based on-off valves. Because the flow rate cannot be continuously and smoothly controlled, this not only causes significant mechanical, pressure, and flow shocks that damage the support or hydraulic system, but also leads to inaccurate position control of the hydraulic cylinders, affecting the support's posture and its coupling with the surrounding rock, and impacting the support's level of intelligence. Therefore, to achieve intelligent, safe, stable, and efficient hydraulic support, it is urgent to transform the existing on-off control technology to achieve continuous and smooth flow rate control.

[0003] Proportional control technology is the fundamental way to solve the above problems, and the proportional control valve is the key to realizing this technology. Therefore, this invention proposes a novel three-stage electro-hydraulic proportional control valve. This valve can precisely, continuously, and smoothly adjust the valve orifice size and flow rate, solving the various impact problems and inaccurate hydraulic cylinder positioning issues caused by existing electro-hydraulic switching valves, as well as the low control accuracy of the main valve orifice size of existing pilot-operated water-based proportional valves. Summary of the Invention

[0004] To address the aforementioned technical problems, this disclosure provides a three-stage electro-hydraulic proportional control valve that can improve the control accuracy of the valve orifice size of the hydraulic main valve core and achieve continuous and smooth flow control.

[0005] This disclosure provides a three-stage electro-hydraulic proportional control valve, comprising:

[0006] The main valve assembly includes a hydraulically controlled main valve core;

[0007] The pilot component includes a first pilot mechanism and a second pilot mechanism. The first pilot mechanism includes a first pilot mechanism I and a first pilot mechanism II with identical structures. The second pilot mechanism includes a second pilot mechanism I and a second pilot mechanism II with identical structures. The first pilot mechanism I and the first pilot mechanism II are connected to the same pressure source. The second pilot mechanism I and the second pilot mechanism II are coaxial with the hydraulic main valve core and are arranged opposite to each other at both ends of the hydraulic main valve core. Both second pilot mechanisms are two-position two-way structures.

[0008] The outer ends of the second pilot mechanism I and the second pilot mechanism II are respectively provided with a first cavity and a sixth cavity. The first cavity is connected to the liquid outlet of the first pilot mechanism I, and the sixth cavity is connected to the liquid outlet of the first pilot mechanism II. The second pilot mechanism I and the second pilot mechanism II are also provided with a reset mechanism. The two ends of the hydraulic control main valve core are respectively provided with a third cavity and a fourth cavity. The third cavity is connected to the liquid outlet of the second pilot mechanism I, and the liquid inlet of the second pilot mechanism I is connected to the main liquid inlet. The third cavity is also connected to the liquid inlet of the second pilot mechanism II. The fourth cavity is connected to the low-pressure return port or the oil tank.

[0009] Optionally, the first pilot mechanism I and the first pilot mechanism II are proportional pressure reducing valves, or proportional directional valves, or pressure output circuits composed of high-speed switching valves and hydraulic resistance components.

[0010] Optionally, the reciprocating linear motion of the second pilot mechanism I and the second pilot mechanism II along the axis of the hydraulic main valve core acts on both ends of the hydraulic main valve core, and each includes a pilot valve seat and a pilot valve core, wherein the pilot valve core is coaxially disposed in the pilot valve seat;

[0011] One end of the pilot valve core is connected to a pilot flexural component, and the other end of the pilot valve core is provided with an axial through hole at the position corresponding to the central axis of the pilot valve seat. A push rod coaxial with the pilot valve core and capable of reciprocating motion is inserted in the axial through hole. The push rod is clearance-fitted with the axial through hole. Several radial liquid inlet holes are provided at the position of the pilot valve seat near the other end of the pilot valve core.

[0012] Optionally, the two ends of the hydraulic main valve core are sequentially provided with a clamping plug and the pilot component along the axial direction. The clamping plug has a polygonal central hole in the axial direction to accommodate the push rod, and a radial gap is left between the polygonal central hole and the push rod.

[0013] Optionally, the reset mechanism includes a proportional spring, and the push rod has a boss;

[0014] One end of the reset mechanism is connected to the boss, and the other end is fixed to the main valve component, so that when the pressure of the first pilot mechanism is zero, the push rod is driven by the reset mechanism to return to the initial zero position.

[0015] The main valve component is provided with a second cavity and a fifth cavity at the positions corresponding to the reset mechanisms of the second pilot mechanism I and the second pilot mechanism II.

[0016] Optionally, the main valve component further includes a main outlet valve sleeve, a main valve seat, and a high-pressure valve sleeve, wherein the main outlet valve sleeve, the main valve seat, and the high-pressure valve sleeve are connected sequentially along the axial direction of the hydraulic main valve core;

[0017] The hydraulically controlled main valve core is a cone valve. The valve stem of the hydraulically controlled main valve core has a truncated cone. The left end valve stem of the hydraulically controlled main valve core is located in the right end axial hole of the main outlet valve sleeve. The left end face of the hydraulically controlled main valve core and the main outlet valve sleeve form the third cavity. The right end valve stem of the hydraulically controlled main valve core is located in the left end axial hole of the high-pressure valve sleeve. The right end face of the hydraulically controlled main valve core and the high-pressure valve sleeve form the fourth cavity.

[0018] The hydraulic main valve core has mounting holes on its two end faces along the axial direction for mounting the second pilot mechanism. The hydraulic main valve core also has a first radial small hole and a second radial small hole at its two ends. The positions of the first radial small hole and the second radial small hole are respectively connected to their respective guide sleeves. The hydraulic main valve core also has a first annular groove and a second annular groove at its two ends. The first annular groove and the second annular groove are respectively connected to the first radial small hole and the second radial small hole.

[0019] Optionally, the main valve component further includes two end caps, which are respectively disposed at opposite ends of the main outlet valve sleeve and the high-pressure valve sleeve. One end cap forms a second cavity with the axial hole of the main outlet valve sleeve, and the other end cap forms a fifth cavity with the axial hole of the high-pressure valve sleeve. The two push rods form a first cavity and a sixth cavity with the two end caps, respectively. The first cavity and the sixth cavity are respectively disposed corresponding to the second cavity and the fifth cavity.

[0020] A seventh radial hole is provided on the end cap near the main outlet valve sleeve. One end of the seventh radial hole is connected to the first cavity, and the other end is connected to the output end of the corresponding first pilot mechanism I. An eighth radial hole is provided on the end cap near the high pressure valve sleeve. One end of the eighth radial hole is connected to the sixth cavity, and the other end is connected to the output end of the corresponding first pilot mechanism II.

[0021] Optionally, the main outlet valve sleeve is provided with a first radial hole, a second radial hole, a third radial hole and a main outlet in sequence along the axial direction;

[0022] The high-pressure valve sleeve is provided with the main liquid inlet, the fourth radial hole, the fifth radial hole and the sixth radial hole in sequence along the axial direction;

[0023] One end of the first radial hole is connected to the second cavity, and the other end is connected to the low-pressure return port or the oil tank;

[0024] One end of the second radial hole is connected to the third cavity, and the other end is connected to the fourth radial hole through an oil passage;

[0025] One end of the third radial hole is connected to the first annular groove, and the other end is connected to the main liquid inlet through an oil passage.

[0026] One end of the fourth radial hole is connected to the second annular groove, and the other end is connected to the second radial hole through an oil passage;

[0027] One end of the fifth radial hole is connected to the fourth cavity, and the other end is connected to the low-pressure return port or the oil tank.

[0028] One end of the sixth radial hole is connected to the fifth cavity, and the other end is connected to the low-pressure return port or the oil tank.

[0029] The technical solution provided in this disclosure has the following advantages compared with the prior art:

[0030] This embodiment provides a three-stage electro-hydraulic proportional control valve. High-pressure fluid enters the third chamber through the main inlet, the inlet of the second pilot mechanism I, and the outlet of the second pilot mechanism I. The third chamber is also connected to the inlet of the second pilot mechanism II. The fourth chamber is connected to the low-pressure return port or the oil tank, so that the high-pressure fluid in the third chamber enters the fourth chamber through the second pilot mechanism II and then returns to the oil tank. This realizes the opening or closing of the hydraulic main valve core, and achieves continuous and smooth control of the opening amount, speed, flow rate and the hydraulic main valve core when opening or closing. It reduces the mechanical and pressure flow impact of the hydraulic support and realizes the precise control of the hydraulic support. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0032] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the three-stage electro-hydraulic proportional control valve described in an embodiment of this disclosure.

[0034] Among them, 1. First pilot mechanism; 1.1 First pilot mechanism I; 1.2 First pilot mechanism II; 2. End cap; 3. Push rod; 4. Main outlet valve sleeve; 5. Reset mechanism; 6. Compression plug; 7. Pilot valve seat; 8. Small ball; 9. Spring seat; 10. Pilot spring; 11. Guide sleeve; 12. Hydraulic main valve core; 13. Main valve seat; 14. Main spring; 15. High pressure valve sleeve; 16. Second pilot mechanism I; 7. Second pilot mechanism II; 18. First cavity; 19. Second cavity; 20. Third cavity; 21. Fourth cavity; 22. Fifth cavity; 23. Sixth cavity; a. First radial orifice; b. Second radial orifice; k1. First radial orifice; k2. Second radial orifice; k3. Third radial orifice; k4. Fourth radial orifice; k5. Fifth radial orifice; k6. Sixth radial orifice; A. Main outlet; P. Main inlet. Detailed Implementation

[0035] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0036] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0037] Reference Figure 1 As shown, this embodiment of the present disclosure provides a three-stage electro-hydraulic proportional control valve, including a main valve component and a pilot component.

[0038] The main valve component includes a hydraulically controlled main valve core 12, and the pilot component includes a first pilot mechanism 1 and a second pilot mechanism. The first pilot mechanism includes a first pilot mechanism I1.1 and a first pilot mechanism II1.2 with identical structures, and the second pilot mechanism includes a second pilot mechanism I16 and a second pilot mechanism II17 with identical structures. The first pilot mechanism I1.1 and the first pilot mechanism II1.2 are connected to the same pressure source. The second pilot mechanism I16 and the second pilot mechanism II17 are coaxial with the hydraulically controlled main valve core 12 and are arranged facing each other at both ends of the hydraulically controlled main valve core 12. Both second pilot mechanisms are two-position two-way structures, and the two second pilot mechanisms can reciprocate linearly and act on both ends of the hydraulically controlled main valve core 12. Specifically, there are two of each of the first pilot mechanism 1 and the second pilot mechanism. The first pilot mechanism I 1.1 and the first pilot mechanism II 1.2 have the same structure and are connected to the same pressure source. Both are pressure output control methods. The second pilot mechanism I 16 and the second pilot mechanism II 17 have the same structure and are coaxially arranged at both ends of the hydraulic control main valve core 12. The second pilot mechanism I 16 and the second pilot mechanism II 17 are both two-position two-way structures and can move along the axial direction of the hydraulic control main valve core 12, thereby driving the hydraulic control main valve core 12 to move.

[0039] The second pilot mechanism I 16 and the second pilot mechanism II 17 are respectively provided with a first cavity 18 and a sixth cavity 23 at their outer ends. The first cavity 18 is connected to the liquid outlet of the first pilot mechanism I 1.1, and the sixth cavity 23 is connected to the liquid outlet of the first pilot mechanism II 1.2. The second pilot mechanism I 16 and the second pilot mechanism II 17 are also provided with a reset mechanism 5. The two ends of the hydraulic control main valve core 12 are respectively provided with a third cavity 20 and a fourth cavity 21. The third cavity 20 is connected to the liquid outlet of the second pilot mechanism I 16, the liquid inlet of the second pilot mechanism I 16 is connected to the main liquid inlet P, the third cavity 20 is also connected to the liquid inlet of the second pilot mechanism II 17, and the fourth cavity 21 is connected to the low-pressure return port or the oil tank. Specifically, the first cavity 18 and the sixth cavity 23 are coaxially arranged with the second pilot mechanism I 16, the second pilot mechanism II 17, and the hydraulic control main valve core 12. The first cavity 18 is connected to the liquid outlet of the first pilot mechanism I 1.1, and the sixth cavity 23 is connected to the liquid outlet of the first pilot mechanism II 1.2, forming a liquid circuit between the first cavity 18 and the sixth cavity 23. The second pilot mechanism I 16 and the second pilot mechanism II 17 are also provided with a reset mechanism 5, which can drive the second pilot mechanism I 16 and the second pilot mechanism II 17 to return to their initial positions for the next operation. The hydraulic control main valve core 12 is also provided with a third cavity 20 and a fourth cavity 21 at both ends, respectively. The third cavity 20 is connected to the liquid outlet of the second pilot mechanism I 16. The inlet of the second pilot mechanism I16 is connected to the main inlet P, so that the high-pressure fluid enters the third cavity 20 through the main inlet P, the inlet of the second pilot mechanism I16, and the outlet of the second pilot mechanism I16. The third cavity 20 is also connected to the inlet of the second pilot mechanism II17. The fourth cavity 21 is connected to the low-pressure return port or the oil tank, so that the high-pressure fluid in the third cavity 20 enters the fourth cavity 21 through the second pilot mechanism II17 and then returns to the oil tank. In this way, the hydraulic control main valve core 12 is opened or closed, and the opening amount, speed, flow rate and continuous smooth control of the hydraulic control main valve core 12 are realized. This reduces the mechanical and pressure flow impact of the hydraulic support and realizes the precise control of the hydraulic support.

[0040] Furthermore, the first pilot mechanism I1.1 and the first pilot mechanism II1.2 are either proportional pressure reducing valves, proportional directional valves, or pressure output circuits composed of high-speed switching valves and hydraulic resistance components. When the first pilot mechanism I is not operated under normal conditions, there is no pressure output.

[0041] In some embodiments, both the second pilot mechanism I 16 and the second pilot mechanism II 2.2 include a pilot valve seat 7 and a pilot valve core. The pilot valve core is coaxially disposed within the pilot valve seat 7. One end of the pilot valve core is connected to the pilot directional element 10, and the other end of the pilot valve core is provided with an axial through hole at the position corresponding to the central axis of the pilot valve seat 7. A push rod 3, which is coaxial with the pilot valve core and can reciprocate, passes through the axial through hole. The push rod 3 is clearance-fitted with the axial through hole. Several radial liquid inlet holes are provided at the position of the pilot valve seat 7 near the other end of the pilot valve core. Specifically, the pilot valve core is housed inside the pilot valve seat 7 and is coaxially arranged with the pilot valve seat 7. One end of the pilot valve core is connected to a pilot spring 10, which prevents the pilot valve core from directly contacting one end of the pilot valve seat 7 with a large impact force during movement, thus avoiding damage to the pilot valve core and the pilot valve seat 7. The pilot spring 10 can be a spring or any component that can play a buffering role. The other end of the pilot valve core has an axial through hole at the position corresponding to the central axis of the pilot valve seat 7, allowing the push rod 3 to pass through the axial through hole along the axial direction of the hydraulic main valve core 5. The reciprocating motion, with the clearance fit between the push rod 3 and the axial through hole, allows the high-pressure liquid entering from the main inlet P to enter the first pilot mechanism 1, and then enter the third cavity 20 through the gap between the push rod 3 and the axial through hole. The high-pressure liquid exiting from the third cavity 20 enters the second pilot mechanism II 2.2, and then enters the fourth cavity 21, realizing the opening or closing of the hydraulic control main valve core 12. Several radial liquid inlet holes are opened on the other end of the pilot valve seat 7 near the pilot valve core. These liquid inlet holes are the liquid inlet holes of the second pilot mechanism I 16 and the second pilot mechanism II 2.2.

[0042] Furthermore, at both ends of the hydraulic main valve core 12, a clamping plug 11 and a pilot component are sequentially arranged axially inward. The clamping plug 11 has a polygonal central hole in the axial direction to accommodate the push rod 3, and a radial clearance is left between the polygonal central hole and the push rod 3. Specifically, the pilot component includes a pilot valve seat 7, a guide sleeve 11, a small ball 8, and a spring seat 9. Starting from the end face of the hydraulic main valve core 12, the clamping plug 6, the pilot valve seat 7, and the guide sleeve 11 are arranged sequentially. These three can also be considered as a mechanical unit. The pilot valve core is a cone valve, and the small ball 8 and the spring seat 9 can replace the cone valve. The clamping plug 6 has a polygonal central hole in the axial direction. The polygonal central hole is coaxially arranged with the pilot valve seat 7, the pilot valve core, and the hydraulic main valve core 12. A radial clearance is left between the push rod 3 and the polygonal central hole, so that the high-pressure fluid flowing into the second pilot mechanism can flow into the third cavity 20 or the fourth cavity 21.

[0043] In some embodiments, the reset mechanism 5 includes a proportional spring, and the push rod 3 has a boss. One end of the reset mechanism 5 is connected to the boss, and the other end is fixed to the main valve component, so that when the pressure in the first pilot mechanism 1 is zero, the push rod 3 is driven to return to the initial zero position by the reset mechanism 5. The main valve component is provided with a second cavity 19 and a fifth cavity 22 at the positions corresponding to the reset mechanism 5 of the second pilot mechanism I 16 and the second pilot mechanism II 17. Specifically, the reset mechanism 5 can be a proportional spring, or any component with elasticity that can drive the push rod 3 to retract. The end of the push rod 3 away from the third cavity 20 is provided with a boss. One end of the reset mechanism 5 is connected to the boss, and the other end is fixed to the main valve component. When the pressure in the first pilot mechanism 1 is zero, the reset mechanism 5 can drive the push rod 3 to return to the initial zero position to prepare for the next operation. The second cavity 19 and the fifth cavity 22 are used to accommodate the reset mechanism 5.

[0044] Furthermore, the main valve assembly also includes a main outlet valve sleeve 4, a main valve seat 13, and a high-pressure valve sleeve 15, which are connected sequentially along the axial direction of the hydraulically controlled main valve core 12. The hydraulically controlled main valve core 12 is a cone valve with a frustum on its valve stem. The left end valve stem of the hydraulically controlled main valve core 12 is located in the right end axial hole of the main outlet valve sleeve 4, forming a third cavity 20 between the left end face of the hydraulically controlled main valve core 12 and the main outlet valve sleeve 4. The right end valve stem of the hydraulically controlled main valve core 12 is located in the left end axial hole of the high-pressure valve sleeve 15, forming a fourth cavity 21 between the right end face of the hydraulically controlled main valve core 12 and the high-pressure valve sleeve 15. Specifically, the main outlet valve sleeve 4, the main valve seat 13, and the high-pressure valve sleeve 15 are arranged sequentially from left to right along the axial direction of the hydraulic control main valve core 12. A third cavity 20 is formed between the left end face of the hydraulic control main valve core 12 and the main outlet valve sleeve 4, and a fourth cavity 21 is formed between the right end face of the hydraulic control main valve core 12 and the high-pressure valve sleeve 15. This allows the high-pressure fluid to flow into the third cavity 20 and the fourth cavity 21 respectively through the second pilot mechanism, thus forming a complete hydraulic control circuit. A main spring 14 is provided between the high-pressure valve sleeve 15 and the hydraulic control main valve core 12 to prevent interference between the hydraulic control main valve core 12 and the high-pressure valve sleeve 15 when the valve moves.

[0045] The hydraulic main valve core 12 has mounting holes on its two end faces along the axial direction for mounting the second pilot mechanism. The hydraulic main valve core 12 also has a first radial small hole a and a second radial small hole b at its two ends. The positions of the first radial small hole a and the second radial small hole b are respectively connected to their corresponding guide sleeves 11. The hydraulic main valve core 12 also has a first annular groove and a second annular groove at its two ends. The first annular groove and the second annular groove are respectively connected to the first radial small hole a and the second radial small hole b. Specifically, two second pilot mechanisms are respectively installed in the mounting holes at both ends of the hydraulic main valve core 12. The hydraulic main valve core 12 is also provided with a first radial small hole a and a second radial small hole b at both ends. The first radial small hole a is connected to the guide sleeve 11 of the second pilot mechanism I 16, and the second radial small hole b is connected to the guide sleeve 11 of the second pilot mechanism II 17. The hydraulic main valve core 12 is also provided with a first annular groove and a second annular groove at both ends. The first annular groove is connected to the first radial small hole a, and the second annular groove is connected to the second radial small hole b. This allows the high-pressure liquid to flow into the second pilot mechanism I 16 through the main inlet P, the first annular groove, and the first radial small hole, and thus enter the third cavity 20. The high-pressure liquid in the third cavity 20 enters the second pilot mechanism II 17 through the second annular groove and the second radial small hole b, and thus enters the fourth cavity 21.

[0046] Furthermore, the main valve component also includes two end caps 2, which are respectively disposed at opposite ends of the main outlet valve sleeve 4 and the high pressure valve sleeve 15. One end cap 2 forms a second cavity 19 between itself and the axial hole of the main outlet valve sleeve 4, and the other end cap 2 forms a fifth cavity 22 between itself and the axial hole of the high pressure valve sleeve 15. The two push rods 3 form a first cavity 18 and a sixth cavity 23 between themselves and the two end caps 2, respectively. The first cavity 18 and the sixth cavity 23 are respectively disposed corresponding to the second cavity 19 and the fifth cavity 22. Specifically, one end cap 2 is threaded to or fixed to the main outlet valve sleeve 4 by screws, forming a second cavity 19 between it and the axial hole of the main outlet valve sleeve 4 to accommodate the reset mechanism 5. The other end cap 2 is threaded to or fixed to the high pressure valve sleeve 15 by screws, forming a fifth cavity 22 between it and the axial hole of the high pressure valve sleeve 15 to accommodate the reset mechanism 5. The two push rods 3 and the two end caps 2 respectively form a first cavity 18 and a sixth cavity 23. The first cavity 18 and the sixth cavity 23 control the movement of the corresponding push rods 3 by the pressure inside their own cavities.

[0047] A seventh radial hole k7 is provided on the end cap 2 near the main outlet valve sleeve 4. One end of the seventh radial hole k7 is connected to the first cavity 18, and the other end is connected to the output end of the corresponding first pilot mechanism I1.1. An eighth radial hole k8 is provided on the end cap 2 near the high pressure valve sleeve 15. One end of the eighth radial hole k8 is connected to the sixth cavity 23, and the other end is connected to the output end of the corresponding first pilot mechanism II1.2. Specifically, the first pilot mechanism I1.1 and the first pilot mechanism II1.2 are connected to the same pressure source. By providing the seventh radial hole k7 and the eighth radial hole k8, the gas source can be delivered to the first cavity 18 and the sixth cavity 23 respectively through the seventh radial hole k7 and the eighth radial hole k8 to adjust the pressure in the first cavity 18 and the sixth cavity 23, thereby acting on the corresponding push rod 3, causing the push rod 3 to move along the axial direction of the hydraulic control main valve core 12, thereby driving the hydraulic control main valve core 12 to move and realize the opening or closing of the hydraulic control main valve core 12. In other words, by adjusting the pressure of the first cavity 18 and the sixth cavity 23, the speed of the push rod 3 can be controlled, thereby enabling continuous and smooth control of the opening amount, speed and flow rate when the hydraulic main valve core 12 is opened or closed.

[0048] Furthermore, the main outlet valve sleeve 4 is provided with a first radial hole k1, a second radial hole k2, a third radial hole k3 and a main outlet port A in sequence along the axial direction; the high-pressure valve sleeve 15 is provided with a main inlet port P, a fourth radial hole k4, a fifth radial hole k5 and a sixth radial hole k6 in sequence along the axial direction; one end of the first radial hole k1 is connected to the second cavity 19 and the other end is connected to the low-pressure return port or the oil tank; one end of the second radial hole k2 is connected to the third cavity 20 and the other end is connected to the fourth radial hole k4 through an oil passage; one end of the third radial hole k3 is connected to the first annular groove and the other end is connected to the main inlet port P through an oil passage; one end of the fourth radial hole k4 is connected to the second annular groove and the other end is connected to the second radial hole k2 through an oil passage; one end of the fifth radial hole k5 is connected to the fourth cavity 21 and the other end is connected to the low-pressure return port or the oil tank; one end of the sixth radial hole k6 is connected to the fifth cavity 22 and the other end is connected to the low-pressure return port or the oil tank.

[0049] The three-stage electro-hydraulic proportional control valve described in this embodiment operates as follows:

[0050] Initially, the first pilot mechanism 1 does not operate, and the pressure in the first cavity 18 and the sixth cavity 23 is zero. The left push rod 3 abuts against the corresponding ball 8, but the ball valve port where the ball 8 is located is in the closed state. The right push rod disengages from the right ball, and the distance of disengagement is the stroke of the hydraulic control main valve core 12. The hydraulic control main valve core 12 is in the closed state, that is, the PA channel is closed.

[0051] By controlling the first pilot mechanism I1.1, the output pressure gradually increases. At this time, the pressure in the first cavity 18 gradually increases, and the left end push rod 3 gradually moves to the right. The push rod 3 pushes the small ball 8 away from the pilot valve seat 7 by a certain distance. The high pressure liquid reaches the third radial hole k3 from the main inlet P through the external channel. After passing through the first radial hole a, the ball valve port of the small ball 8, the annular radial gap formed by the push rod 3, the pilot valve seat 7, and the clamping screw plug 6, it reaches the third cavity 20. When the pressure in the third cavity 20 rises to the opening pressure, the hydraulic control main valve core 12 moves to the right, and the PA channel of the main valve component is connected to supply liquid to the outside until the ball valve port of the small ball 8 closes again. In this way, the opening amount of the PA channel of the hydraulic control main valve core 12 can remain stable. By continuously repeating this process, the step-by-step opening of the hydraulic main valve core 12 can be controlled until it reaches its maximum opening. At this point, the right-end push rod abuts against the right-end ball, rapidly adjusting the first pilot mechanism I1.1 to reduce the pressure in the first cavity 18 to zero. The left-end push rod 3 then returns to its initial zero position under the action of the reset mechanism 5. By controlling the pressure in the first cavity 18, the proportional opening process described above can control the rightward displacement and speed of the push rod 3, thus achieving continuous and smooth control of the opening amount, opening speed, and flow rate of the hydraulic main valve core 12.

[0052] Using the same method as the proportional opening process described above, the right-end push rod of the first pilot mechanism II1.2 is moved to the left. The liquid in the third cavity 20 will pass through the second radial hole k2, the external channel, the fourth radial hole k4, the second radial small hole b, the ball valve port of the right-end small ball, and the annular radial gap formed by the right-end push rod, the right-end pilot valve seat, and the right-end clamping plug, reaching the fourth cavity 21, and then returning to the oil tank through the fifth radial hole k5. The hydraulic control main valve core 12 moves to the left, and the opening of the PA channel of the main valve component gradually decreases until the ball valve port of the right-end small ball closes again. By continuously repeating this process, the opening of the hydraulic control main valve core 12 can be gradually reduced until the opening of the hydraulic control main valve core 12 is closed to zero. At this time, the left-end push rod 3 abuts against the left-end small ball 8. At this time, the first pilot mechanism II1.2 is adjusted so that the pressure in the first cavity 18 becomes zero, and the right-end push rod returns to the initial zero position under the action of the right-end reset mechanism. The above-mentioned proportional closing process can achieve continuous and smooth control of the opening amount, closing speed and flow rate when the hydraulic main valve core 12 is closed by controlling the displacement and speed of the right end push rod to the left.

[0053] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0054] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-stage electro-hydraulic proportional control valve, characterized in that, include: The main valve assembly includes a hydraulically controlled main valve core (12). The pilot component includes a first pilot mechanism (1) and a second pilot mechanism. The first pilot mechanism includes a first pilot mechanism I (1.1) and a first pilot mechanism II (1.2) with the same structure. The second pilot mechanism includes a second pilot mechanism I (16) and a second pilot mechanism II (17) with the same structure. The first pilot mechanism I (1.1) and the first pilot mechanism II (1.2) are connected to the same pressure source. The second pilot mechanism I (16) and the second pilot mechanism II (17) are coaxial with the hydraulic main valve core (12) and are arranged opposite to each other at both ends of the hydraulic main valve core (12). Both second pilot mechanisms are two-position two-way structures. The outer ends of the second pilot mechanism I (16) and the second pilot mechanism II (17) are respectively provided with a first cavity (18) and a sixth cavity (23). The first cavity (18) is connected to the liquid outlet of the first pilot mechanism I (1.1), and the sixth cavity (23) is connected to the liquid outlet of the first pilot mechanism II (1.2). The second pilot mechanism I (16) and the second pilot mechanism II (17) are also provided with a reset mechanism (5). The two ends of the hydraulic control main valve core (12) are respectively provided with a third cavity (20) and a fourth cavity (21). The third cavity (20) is connected to the liquid outlet of the second pilot mechanism I (16), and the liquid inlet of the second pilot mechanism I (16) is connected to the main liquid inlet (P) of the main valve component. The third cavity (20) is also connected to the liquid inlet of the second pilot mechanism II (17). The fourth cavity (21) is connected to the low pressure return port or the oil tank. The second pilot mechanism I (16) and the second pilot mechanism II (17) act on both ends of the hydraulic main valve core (12) through reciprocating linear motion along the axis of the hydraulic main valve core. The second pilot mechanism I (16) and the second pilot mechanism II (17) both include a pilot valve seat (7) and a pilot valve core. The pilot valve core is coaxially disposed in the pilot valve seat (7). One end of the pilot valve core is connected to the pilot valve component (10), and the other end of the pilot valve core is provided with an axial through hole at the position of the central axis of the pilot valve seat (7). A push rod (3) coaxial with the pilot valve core and capable of reciprocating motion is inserted in the axial through hole. The push rod (3) is clearance-fitted with the axial through hole. Several radial liquid inlet holes are provided at the position of the pilot valve seat (7) near the other end of the pilot valve core.

2. The three-stage electro-hydraulic proportional control valve according to claim 1, characterized in that, The hydraulic main valve core (12) has a clamping plug (6) and the pilot component arranged sequentially at both ends along the axial direction. The clamping plug (6) has a polygonal center hole in the axial direction to accommodate the push rod (3). A radial gap is left between the polygonal center hole and the push rod (3).

3. The three-stage electro-hydraulic proportional control valve according to claim 1, characterized in that, The reset mechanism (5) includes a proportional spring, and the push rod (3) has a boss; One end of the reset mechanism (5) is connected to the boss, and the other end is fixed to the main valve component, so that when the pressure of the first pilot mechanism (1) is zero, the push rod (3) is driven to return to the initial zero position by the reset mechanism (5); The main valve component is provided with a second cavity (19) and a fifth cavity (22) at the position of the reset mechanism (5) of the second pilot mechanism I (16) and the second pilot mechanism II (17).

4. The three-stage electro-hydraulic proportional control valve according to claim 3, characterized in that, The main valve component also includes a main outlet valve sleeve (4), a main valve seat (13), and a high-pressure valve sleeve (15), which are connected sequentially along the axial direction of the hydraulic main valve core (12). The hydraulic control main valve core (12) is a cone valve. The valve stem of the hydraulic control main valve core (12) has a cone. The left end valve stem of the hydraulic control main valve core (12) is located in the right end axial hole of the main outlet valve sleeve (4). The left end face of the hydraulic control main valve core (12) and the main outlet valve sleeve (4) form the third cavity (20). The right end valve stem of the hydraulic control main valve core (12) is located in the left end axial hole of the high pressure valve sleeve (15). The right end face of the hydraulic control main valve core (12) and the high pressure valve sleeve (15) form the fourth cavity (21). The two end faces of the hydraulic main valve core (12) are provided with mounting holes along the axial direction for installing the second pilot mechanism. The two ends of the hydraulic main valve core (12) are respectively provided with a first radial small hole (a) and a second radial small hole (b). The positions of the first radial small hole (a) and the second radial small hole (b) are respectively connected to their respective guide sleeves (11). The two ends of the hydraulic main valve core (12) are respectively provided with a first annular groove and a second annular groove. The first annular groove and the second annular groove are respectively connected to the first radial small hole (a) and the second radial small hole (b).

5. The three-stage electro-hydraulic proportional control valve according to claim 4, characterized in that, The main valve component also includes two end caps (2), which are respectively disposed at opposite ends of the main outlet valve sleeve (4) and the high pressure valve sleeve (15). One end cap (2) forms a second cavity (19) between the axial hole of the main outlet valve sleeve (4), and the other end cap (2) forms a fifth cavity (22) between the axial hole of the high pressure valve sleeve (15). The two push rods (3) form a first cavity (18) and a sixth cavity (23) between the two end caps (2), respectively. The first cavity (18) and the sixth cavity (23) are respectively disposed corresponding to the second cavity (19) and the fifth cavity (22). A seventh radial hole (k7) is provided on the end cap (2) near the main outlet valve sleeve (4). One end of the seventh radial hole (k7) is connected to the first cavity (18), and the other end is connected to the output end of the corresponding first pilot mechanism I (1.1). An eighth radial hole (k8) is provided on the end cap (2) near the high pressure valve sleeve (15). One end of the eighth radial hole (k8) is connected to the sixth cavity (23), and the other end is connected to the output end of the corresponding first pilot mechanism II (1.2).

6. The three-stage electro-hydraulic proportional control valve according to claim 5, characterized in that, The main outlet valve sleeve (4) is provided with a first radial hole (k1), a second radial hole (k2), a third radial hole (k3) and a main outlet (A) in sequence along the axial direction. The high-pressure valve sleeve (15) is provided with the main liquid inlet (P), the fourth radial hole (k4), the fifth radial hole (k5) and the sixth radial hole (k6) in sequence along the axial direction. One end of the first radial hole (k1) is connected to the second cavity (19), and the other end is connected to the low-pressure return port or the oil tank; One end of the second radial hole (k2) is connected to the third cavity (20), and the other end is connected to the fourth radial hole (k4) through an oil passage; One end of the third radial hole (k3) is connected to the first annular groove, and the other end is connected to the main inlet (P) through an oil passage; One end of the fourth radial hole (k4) is connected to the second annular groove, and the other end is connected to the second radial hole (k2) through an oil passage; One end of the fifth radial hole (k5) is connected to the fourth cavity (21), and the other end is connected to the low-pressure return port or the oil tank; One end of the sixth radial hole (k6) is connected to the fifth cavity (22), and the other end is connected to the low-pressure return port or the oil tank.

Images