Electro-hydraulic proportional valve

Abstract

The application discloses an electro-hydraulic proportional valve. The electro-hydraulic proportional valve comprises a valve core, a valve sleeve, a valve body, a left end cover, a right end cover and a driving mechanism. The valve sleeve is sleeved outside the valve core. The valve body is sleeved outside the valve sleeve and fixedly connected with the valve sleeve. The left end cover is arranged on one end of the valve body and forms a left sensitive cavity with the valve body and the valve sleeve. The right end cover is arranged on the other end of the valve body and forms a right sensitive cavity with the valve body and the valve sleeve. The driving mechanism is arranged outside the valve body. The transmission mechanism is connected with the driving mechanism and the valve core respectively. The transmission mechanism is used for driving the valve core to rotate along the circumference of the valve core relative to the valve sleeve under the driving of the driving mechanism, so that a hydraulic pressure difference is generated between the left sensitive cavity and the right sensitive cavity. The valve core moves along the axis of the valve core relative to the valve sleeve under the action of the hydraulic pressure difference. In this way, high pressure and large flow can be realized, and the structure of the electro-hydraulic proportional valve is simplified.

Description

Technical Field

[0001] This application relates to the field of fluid transmission and control technology, and in particular to an electro-hydraulic proportional valve. Background Technology

[0002] An electro-hydraulic proportional valve is a type of hydraulic valve that falls between a switch valve and a servo valve. It can continuously control parameters such as hydraulic fluid pressure and flow rate according to an input signal, making these parameters change proportionally to the input signal. It is widely used in hydraulic systems and, compared to servo valves, is more affordable and has stronger resistance to contamination.

[0003] Currently, the most commonly used electro-hydraulic proportional valves on the market are generally of two types: direct-acting and pilot-operated. Direct-acting electro-hydraulic proportional valves are driven by a proportional solenoid, which directly drives the valve core. They have a simple structure, but the solenoid's thrust is limited, making it impossible to achieve high pressure and high flow. Pilot-operated electro-hydraulic proportional valves use a pilot valve to control the pressure changes in the pressure chambers at both ends of the main valve, generating a larger hydraulic pressure to drive the main valve core, achieving high pressure and high flow. However, their structure is more complex. Summary of the Invention

[0004] The main technical problem addressed by this application is to provide an electro-hydraulic proportional valve to achieve high pressure and high flow rate while simplifying the structure of the electro-hydraulic proportional valve.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this application is to provide an electro-hydraulic proportional valve. The electro-hydraulic proportional valve includes: a valve core; a valve sleeve fitted over the valve core; a valve body fitted over the valve sleeve and fixedly connected to it; a drive mechanism disposed outside the valve body; and a transmission mechanism connected to both the drive mechanism and the valve core. The transmission mechanism is used to drive the valve core to rotate circumferentially relative to the valve body under the drive of the drive mechanism, thereby generating a hydraulic differential. Under the action of the hydraulic differential, the valve core moves axially relative to the valve body.

[0006] The beneficial effects of this application are as follows: Unlike the prior art, the electro-hydraulic proportional valve of this application includes: a valve core; a valve sleeve, sleeved outside the valve core; a valve body, sleeved outside the valve sleeve and fixedly connected to the valve sleeve; a left end cap, covering one end of the valve body, forming a left sensitive cavity between the valve body and the valve sleeve; a right end cap, covering the other end of the valve body, forming a right sensitive cavity between the valve body and the valve sleeve; a drive mechanism, disposed outside the valve body; and a transmission mechanism, connected to the drive mechanism and the valve core respectively. The transmission mechanism is used to drive the valve core to rotate circumferentially relative to the valve sleeve under the drive of the drive mechanism, so as to generate a hydraulic difference between the left and right sensitive cavities. Under the action of the hydraulic difference, the valve core moves axially relative to the valve sleeve. This application's electro-hydraulic proportional valve transmits the driving force of the drive mechanism to the valve core through a transmission mechanism, causing the valve core to rotate circumferentially. This solves the problem of insufficient thrust caused by the traditional method of using a proportional electromagnet to directly drive the valve core, thus enabling high pressure and high flow rate. Furthermore, this application uses a single-stage valve core, and the valve core moves axially through the hydraulic differential between its two ends, which is equivalent to a traditional pilot-controlled electro-hydraulic proportional valve using a two-stage valve core. This simplifies the structure of the electro-hydraulic proportional valve. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0008] Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the electro-hydraulic proportional valve of this application;

[0009] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure of the electro-hydraulic proportional valve along line A-A' in the embodiment;

[0010] Figure 3 yes Figure 1 Exploded view of the electro-hydraulic proportional valve in the embodiment;

[0011] Figure 4 yes Figure 1 A top view of the valve core and valve sleeve assembly structure in the electro-hydraulic proportional valve of the embodiment;

[0012] Figure 5 This is a three-dimensional structural schematic diagram of another embodiment of the electro-hydraulic proportional valve of this application;

[0013] Figure 6 yes Figure 5 A schematic diagram of the cross-sectional structure of the electro-hydraulic proportional valve along B-B' in the embodiment;

[0014] Figure 7 yes Figure 5 A schematic diagram of the axial cross-sectional structure of the ball screw in the electro-hydraulic proportional valve of the embodiment. Detailed Implementation

[0015] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0016] The terms "first" and "second" in this application are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise expressly specified. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0017] This application proposes an electro-hydraulic proportional valve, such as Figures 1 to 4 As shown, Figure 1 This is a three-dimensional structural schematic diagram of an embodiment of the electro-hydraulic proportional valve of this application; Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure of the electro-hydraulic proportional valve along line A-A' in the embodiment; Figure 3 yes Figure 1 Exploded view of the electro-hydraulic proportional valve in the embodiment; Figure 4 yes Figure 1This is a top view schematic diagram of the valve core and valve sleeve assembly structure in the electro-hydraulic proportional valve of this embodiment. The electro-hydraulic proportional valve 10 of this embodiment includes: a valve core 11, a valve body 12, a valve sleeve 15, a left end cap 16, a right end cap 17, a drive mechanism 13, and a transmission mechanism 14; wherein, the valve sleeve 15 is sleeved outside the valve core 11; the valve body 12 is sleeved outside the valve sleeve 15 and is fixedly connected to the valve sleeve 15; the left end cap 16 covers one end of the valve body 12 and forms a left sensitive cavity between the left end cap 16 and the valve body 12 and the valve sleeve 15; the right end cap 17 covers the other end of the valve body 12. A right sensitive cavity is formed between the valve body 12 and the valve sleeve 15; the drive mechanism 13 is disposed outside the valve body 12; the transmission mechanism 14 is connected to the drive mechanism 13 and the valve core 11 respectively. The transmission mechanism 14 is used to drive the valve core 11 to rotate relative to the valve sleeve 15 along the circumference of the valve core 11 under the drive of the drive mechanism 13, so that a hydraulic difference is generated between the left and right sensitive cavities. Under the action of the hydraulic difference, the valve core 11 moves relative to the valve sleeve 15 along the axial direction of the valve core 11.

[0018] In this embodiment, the transmission mechanism 14 transmits the driving force generated by the drive mechanism 13 to the valve core 11, and causes the valve core 11 to rotate circumferentially relative to the valve sleeve 15 (valve body 12), thereby opening the valve port of the electro-hydraulic proportional valve 10. As the valve sleeve 15 rotates circumferentially along the valve core 11, a hydraulic pressure difference is generated between the left and right sensitive chambers, and a hydraulic pressure difference is generated at both ends of the valve core 11. Under the action of the hydraulic pressure difference, the valve core 11 moves axially along the valve core 11 so that the valve core 11 reaches the equilibrium position.

[0019] Unlike existing technologies, in this embodiment, the electro-hydraulic proportional valve 10 transmits the driving force of the drive mechanism 13 to the valve core 11 through the transmission mechanism 14, so that the valve core 11 rotates circumferentially. This solves the problem of insufficient thrust caused by the traditional method of using a proportional electromagnet to directly drive the valve core, thus enabling high pressure and high flow rate. Furthermore, this embodiment uses a single-stage valve core 11, and the valve core moves axially through the hydraulic differential between the two ends of the valve core 11. This is equivalent to a traditional pilot-controlled electro-hydraulic proportional valve using a two-stage valve core, resulting in a simple structure and thus simplifying the structure of the electro-hydraulic proportional valve.

[0020] In this embodiment, the valve sleeve 15 enables the communication of flow or hydraulic pressure between the valve body 12 and the valve core 11; the pressure in the left sensitive chamber is equal to the pressure in the right sensitive chamber.

[0021] The left end of the valve sleeve 15 is pressed by the left end cover 16 and fixedly connected to the left end cover 16 by screws; the right end of the valve sleeve 15 is pressed by the right end cover 17 and fixedly connected to the right end cover 17 by screws.

[0022] Existing two-dimensional electro-hydraulic proportional valves employ a hydraulic half-bridge principle for their sensing chambers. The pressure in one sensing chamber is changed by the rotation of the valve core, achieving balance with the high-pressure chamber at the other end via a spiral groove. This eliminates the need for a pilot stage and proportional electromagnet, reducing size and weight and easily achieving high pressure and high flow. However, the single-sided pressure sensing chamber is affected by the back pressure at the low-pressure port, causing pressure changes that influence the valve core's zero position. In contrast, the electro-hydraulic proportional valve 10 in this embodiment uses the pressure difference between both sensing chambers to generate a hydraulic driving force on the valve core 11 that is twice that of a single-sided sensing chamber, improving response speed. Furthermore, the pressure states of both sensing chambers are consistent; the pressure difference generated by the rotation of the valve core 11 changes with factors such as the back pressure at the high-pressure port and return port, but the displacement of the valve core 11 remains unchanged, and its zero position remains constant.

[0023] Optionally, in this embodiment, the valve body 12 has a through hole 121 in the middle, the valve core 11 has a groove 111 in the middle, the drive mechanism 13 is arranged on one side of the valve body 12 along the radial direction of the valve core 11, and the transmission mechanism 14 includes a lever 141. One end of the lever 141 is fixedly connected to the drive mechanism 13, and the other end of the lever 141 passes through the through hole 121 and is embedded in the groove 111. The lever 141 is used to drive the valve core 11 to rotate relative to the valve body 12 along the circumference of the valve core 11 under the drive of the drive mechanism 13.

[0024] In this embodiment, the drive mechanism 13 and the valve core 11 are arranged in a T-shape to avoid the electro-hydraulic proportional valve 10 having an excessively large axial dimension along the valve core 11. Furthermore, the T-shape facilitates the vertical drive of the valve core 10 by the drive mechanism 13, enabling deceleration and torque increase. In other embodiments, the drive mechanism 13 and the valve core 11 can also be arranged in a straight line; no specific limitation is imposed.

[0025] Optionally, the transmission mechanism 14 in this embodiment further includes a transmission rod 142. One end of the transmission rod 142 is connected to the end of the lever 141 away from the valve core 11, and the other end of the transmission rod 142 is connected to the drive mechanism 13. The lever 141 and the transmission rod 142 are eccentrically positioned. The transmission rod 142 rotates under the drive of the drive mechanism 13, causing the lever 141 to rotate around the transmission rod 142. In this embodiment, the eccentrically positioned transmission rod 142 and lever 141 achieve vertical drive of the valve core 11 by the drive mechanism 13. Compared to traditional reducers, the eccentric mechanism structure of this embodiment is simpler. Of course, in other embodiments, a non-eccentric mechanism can also be used to achieve vertical drive of the valve core by the drive mechanism.

[0026] As can be seen from the above analysis, when the drive mechanism 13 drives the transmission rod 142 to rotate, the lever 141 rotates around the transmission rod 142, that is, the lever 141 makes circular motion in a plane perpendicular to the lever 141, that is, it has displacement in two perpendicular directions in this plane. In order to make the lever 141 drive the valve core 11 to rotate circumferentially without moving axially, the dimension of the slot 111 on the valve core 11 along the axial direction of the valve core 11 is larger than the dimension of the slot 111 along the direction perpendicular to the axial direction of the valve core 11 and the axial direction of the transmission rod 142, so that when the lever 141 rotates, the lower end abuts against the side wall of the slot 111 along the direction perpendicular to the axial direction of the valve core 11 and the axial direction of the transmission rod 142.

[0027] Optionally, in this embodiment, the end face of the lever 141 away from the valve core 11 is provided with a slot 101, and the end of the transmission rod 142 near the lever 141 is embedded in the slot 101, and the central axis of the slot 101 and the central axis of the lever 141 are arranged radially apart along the lever 141.

[0028] In this embodiment, the transmission rod 142 and lever 141 are not integrally formed, which facilitates disassembly and replacement. The transmission rod 142 and / or lever 141 can be selectively replaced according to different drive mechanisms 13 and / or different valve cores 11, which can save costs.

[0029] In other embodiments, the transmission rod and the lever can also be integrated, which can improve the stability of the transmission mechanism.

[0030] Optionally, the transmission mechanism 14 in this embodiment further includes a bearing 143, the outer ring of which is fixedly connected to the drive mechanism 13, and the inner ring of which is sleeved on the transmission rod 142.

[0031] This embodiment, by setting bearing 143, can increase the stability of the transmission rod 142 during rotation and increase the driving force on the transmission rod 142.

[0032] To further increase the stability of the transmission rod 142 during rotation, this embodiment includes two spaced-apart bearings 143 mounted on the transmission rod 142. In other embodiments, the number of bearings is not limited.

[0033] Optionally, the drive mechanism 13 in this embodiment includes a motor 131, a drive wheel 132, and a driven wheel 133; wherein the drive wheel 132 is fixedly connected to the rotating shaft of the motor 131; the driven wheel 133 is drivenly connected to the drive wheel 132 and is fixedly connected to the transmission rod 142.

[0034] The motor 131 drives the drive wheel 132 to rotate in a plane perpendicular to the transmission rod 142 via its shaft. The drive wheel 132 drives the driven wheel 133 to rotate in the same plane, and the driven wheel 133 drives the transmission rod 142 to rotate automatically in the same plane.

[0035] In this embodiment, the transmission rod 142 and the driven wheel 133 are coaxially arranged, allowing the transmission rod 142 to move automatically within the plane. In other embodiments, the transmission rod may also be eccentrically arranged with respect to the driven wheel.

[0036] In other embodiments, the transmission rod can be directly driven to rotate by a motor, or the lever can be directly driven or driven by a transmission component to move in a direction perpendicular to the axial direction of the valve core and the axial direction of the transmission rod, so as to drive the valve core to rotate circumferentially relative to the valve body.

[0037] In this embodiment, the driving wheel 132 and the driven wheel 133 can be meshed together using gears; in other embodiments, pulleys and transmission belts can be used instead of gears.

[0038] Optionally, the electro-hydraulic proportional valve 10 in this embodiment further includes a fixed seat 134 and a fixed plate 135. The motor 131 is fixed on the fixed seat 134, the fixed seat 134 is fixed on the fixed plate 135, and the fixed plate 135 is fixed on the valve body 12. The fixed seat 134 is provided with a through hole (not shown in the figure), and the outer ring of the bearing 143 is fixedly connected to the side wall of the through hole on the fixed seat 134.

[0039] Optionally, in this embodiment, the transmission ratio between the driving wheel 132 and the driven wheel 133 is less than 1, so that the driving wheel 132 and the driven wheel 133 form a torque amplification mechanism, which can increase the driving force.

[0040] In other embodiments, different transmission ratios can be achieved by using different radii and numbers of driving wheels and / or different radii and numbers of driven wheels.

[0041] Optionally, the outer side of the valve sleeve 15 is provided with an annular protrusion 151, and the inner side of the valve body 12 is provided with an annular recess (not shown). The annular protrusion 151 is embedded in the annular recess, which can fix the valve sleeve 15 and the valve body 12. This positioning structure facilitates disassembly and installation.

[0042] In other embodiments, other structures, such as locating pins or snap-fits, can be used to achieve a fixed connection between the valve sleeve and the valve body.

[0043] Optionally, in this embodiment, the valve body 12 is provided with a left high-pressure oil port P1, a left working oil port A, a return oil port T, a right working oil port B, and a right high-pressure oil port P2 in sequence along the axial direction of the valve core 11, wherein the pressures of the left high-pressure oil port P1 and the right high-pressure oil port P2 are equal; the valve sleeve 15 is provided with a left sensitive groove s1, a left high-pressure hole p3, a left working groove a, a low-pressure groove t5, a right working groove b, a right high-pressure hole p4, and a right sensitive groove s2 in sequence along the axial direction of the valve core 11, wherein the left sensitive groove s1 is connected to the left sensitive cavity S1, the left high-pressure hole p3 is connected to the left high-pressure oil port P1, the left working groove a is connected to the left working oil port A, the low-pressure groove t5 is connected to the return oil port T, and the right working groove b is connected to the right working oil port B. The valve core 11 is connected to the right high-pressure port P4 and the right high-pressure oil port P2, and the right sensing groove S2 and the right sensing cavity S2. The valve core 11 is provided with a low-pressure flow channel t extending along its axial direction. The low-pressure flow channel t is connected to the return oil port T through the low-pressure groove t5. One end of the valve core 11 is provided with a left sensing high-pressure groove p1 and a left sensing low-pressure groove t3, and the other end of the valve core 11 is provided with a right sensing high-pressure groove p2 and a right sensing low-pressure groove t4. Among them, the left sensing high-pressure groove p1 is connected to the left high-pressure oil port P1, the left sensing low-pressure groove t3 is connected to the low-pressure flow channel t through the low-pressure left hole t1, the right sensing high-pressure groove p2 is connected to the right high-pressure oil port P2, and the right sensing low-pressure groove t4 is connected to the low-pressure flow channel t through the low-pressure right hole t2.

[0044] The low-pressure flow channel t is located on the central axis of the valve core 11; the left sensing high-pressure groove p1 and the left sensing low-pressure groove t3 are centrally symmetrically distributed, and the right sensing high-pressure groove p2 and the right sensing low-pressure groove t4 are centrally symmetrically distributed.

[0045] Optionally, the electro-hydraulic proportional valve 10 in this embodiment further includes: a left bearing 18, a left spring seat 19, a left return spring 20, a right bearing (not shown), a right spring seat (not shown), and a right return spring (not shown); wherein, the left bearing 18 is disposed inside the left end cover 16, and its outer ring is fixedly connected to the left end cover 16; one end of the left spring seat 19 is fixedly connected to one end of the valve core 11, and its other end is sleeved inside the inner ring of the left bearing 18; the left return spring 20 is sleeved outside the left spring seat 19, and one end of it abuts against the left bearing 18, and its other end abuts against the valve core 11; the right bearing is disposed inside the right end cover 17, and its outer ring is fixedly connected to the right end cover 17; one end of the right spring seat is fixedly connected to the other end of the valve core 11, and its other end is sleeved inside the inner ring of the right bearing; the right return spring is sleeved outside the right spring seat, and one end of it abuts against the right bearing, and its other end abuts against the valve core 11.

[0046] Among them, the stiffness of the left return spring 20 and the right return spring are equal, and both the left return spring 20 and the right return spring are under the same compression state.

[0047] Optionally, the valve core 11 is threadedly connected to the left spring seat 19 and the right spring seat respectively. The threaded connection is used to seal the central low-pressure flow channel t of the valve core 11 with the left sensitive cavity S1 and the right sensitive cavity S2. The threaded connection has a transition fit. The valve core 11 is coaxially arranged with the left spring seat 19 and the right spring seat. The left return spring 20 and the right return spring are used to ensure that the valve core 11 is in the neutral position when stationary and to reduce rotational friction when the valve core 11 rotates during dynamic processes.

[0048] The rotation of valve core 11 causes the left sensing chamber S1 to alternately connect with the left sensing high pressure groove p1 and the left sensing low pressure groove t3 of valve core 11. At the same time, the rotation of valve core 11 causes the right sensing chamber S2 to alternately connect with the right sensing low pressure groove p2 and the right sensing high pressure groove t4 of valve core 11. The two end faces of valve core 11 have equal areas. Under the action of the hydraulic difference between the left sensing chamber S1 and the right sensing chamber S2, valve core 11 slides along its axis to a new equilibrium position, realizing the corresponding function.

[0049] When the motor 131 is not activated, the lever 141 is in the middle position, the valve core 11 is in the middle position, and each shoulder of the valve core 11 seals each hole and groove of the valve sleeve 15, and the valve port is not open; the left sensitive groove s1 of the valve sleeve 15 has the same overlapping area as the left low-pressure sensing groove t3 and the left high-pressure sensing groove p1 of the valve core 11, and the left sensitive groove s1 of the valve sleeve 15 is in the middle position of the left low-pressure sensing groove t3 and the left high-pressure sensing groove p1 of the valve core 11; the right sensitive groove s2 of the valve sleeve 15 has the same overlapping area as the right low-pressure sensing groove t4 and the right high-pressure sensing groove p2 of the valve core 11, and the right sensitive groove s2 is in the middle position of the right low-pressure sensing groove t4 and the right high-pressure sensing groove p2 of the valve core 11. Among them, the left sensing low-pressure tank t3 is connected to the return oil port T through the low-pressure left hole t1 and the central low-pressure flow channel t; the right sensing low-pressure tank t4 is connected to the return oil port T through the low-pressure right hole t2 and the central low-pressure flow channel t; the left sensing high-pressure tank p1 is connected to the left high-pressure oil port P1; and the right sensing high-pressure tank p2 is connected to the right high-pressure oil port P2.

[0050] According to the principle of hydraulic damping half-bridge, the pressure relationship between the left sensing chamber S1 and the right sensing chamber S2 satisfies:

[0051]

[0052]

[0053] In the formula, the pressures at the left high-pressure oil port P1 and the right high-pressure oil port P2 are equal, therefore .

[0054] The valve core 11 has the same stiffness and compression as the left return spring 20 and the right return spring, so the spring forces are equal and opposite in direction.

[0055] When the motor 13 is powered on and rotates, if viewed from above, the counterclockwise rotation of the motor 13 shaft is the positive direction of the motor 13's rotation, and if viewed from left to right, the counterclockwise rotation of the valve core 11 is the positive direction of the valve core's rotation. When motor 13 rotates forward at a certain angle, it sequentially drives drive wheel 132, driven wheel 133, transmission rod 142, and lever 141. Utilizing the eccentric mechanism between lever 141 and transmission rod 142, lever 141 causes valve core 11 to rotate forward. At this time, the overlapping area of ​​the left sensing groove s1 of valve sleeve 15 and the left low-pressure sensing groove t3 of valve core 11 increases, while the overlapping area with the left high-pressure sensing groove p1 decreases. That is, the left sensing chamber S1 communicates with the oil outlet T, and the pressure ps1 of the left sensing chamber S1 decreases. Simultaneously, the overlapping area of ​​the right sensing groove s2 of valve sleeve 15 and the right high-pressure sensing groove p2 of valve core 11 increases, while the overlapping area with the right low-pressure sensing groove t4 decreases. That is, the right sensing chamber S2 communicates with the right high-pressure oil port P2, and the pressure ps2 of the right sensing chamber S2 increases.

[0056] At this point, the pressure on the left end face of valve core 11 is less than the pressure on the right end face. Under the action of the axial hydraulic pressure difference, valve core 11 slides to the left along its axial direction. The overlapping area of ​​the left sensing groove s1 of valve sleeve 15 and the left low-pressure sensing groove t3 of valve core 11 gradually decreases, while the overlapping area with the left high-pressure sensing groove p1 gradually increases, until the overlapping areas of the left sensing groove s1 of valve sleeve 15 with the left low-pressure sensing groove t3 and the left high-pressure sensing groove p1 of valve core 11 are equal again. At the same time, the overlapping area of ​​the right sensing groove s2 of valve sleeve 15 and the right high-pressure sensing groove p2 of valve core 11 gradually decreases, while the overlapping area with the right low-pressure sensing groove t4 gradually increases, until the overlapping areas of the right sensing groove s2 of valve sleeve 15 with the right low-pressure sensing groove t4 and the right high-pressure sensing groove p2 of valve core 11 are equal. At this point, the pressure ps1 of the left sensing chamber S1 and the pressure ps2 of the right sensing chamber S2 are equal again, and valve core 11 is in an axial equilibrium position.

[0057] As the valve core 11 moves axially to the left, the valve port gradually opens. The left working oil port A and the return oil port T are connected through the left working groove a and the low-pressure groove t5 of the valve sleeve 15. The right high-pressure oil port P2 and the right working oil port B are connected through the right working groove b and the right high-pressure hole p4 of the valve sleeve 15 until the valve core 11 is in axial balance again.

[0058] Conversely, when motor 131 rotates in the opposite direction by a certain angle, the working principle is similar to that in the forward direction. The high and low pressures at both ends of valve core 11 switch, and the slide valve moves axially to the right until a new equilibrium position is reached, at which point the valve port opens or closes in the reverse direction.

[0059] Among them, the left sensitive groove s1 and the right sensitive groove s2 of the valve sleeve 15 are both inclined grooves; the rotation angle of the motor 131 is reflected on the inclined groove of the valve sleeve 15. The inclined groove is linearly related to the axial movement of the valve core 11. Therefore, the rotation angle of the motor 131 is linearly related to the axial sliding of the valve core 11. Thus, the input signal of the continuously controlled motor 131 can make the valve core 11 continuously and linearly output, realizing the function of the electro-hydraulic proportional directional valve.

[0060] In this embodiment, the electro-hydraulic proportional valve 10 is a three-position four-way electro-hydraulic proportional directional valve.

[0061] This application further proposes another embodiment of an electro-hydraulic proportional valve, such as... Figures 5 to 7 As shown, Figure 5 This is a three-dimensional structural schematic diagram of another embodiment of the electro-hydraulic proportional valve of this application; Figure 6 yes Figure 5 A schematic diagram of the cross-sectional structure of the electro-hydraulic proportional valve along B-B' in the embodiment; Figure 7 yes Figure 5 A schematic cross-sectional view of the ball screw along the axial direction in the electro-hydraulic proportional valve of this embodiment. The difference between the electro-hydraulic proportional valve 50 in this embodiment and the electro-hydraulic proportional valve described above is as follows: 1) The rotating shaft 532 of the motor 531, i.e., the rotor, extends to the housing 533, so that the initial zero position can be adjusted when the power is off, and the precise adjustment can be made by controlling the rotation angle of the motor 531 after the power is on; 2) The lever 534 in this embodiment includes a body (not shown in the figure) and a ball screw 535; wherein, the body is fixedly connected to the rotating shaft 532 of the motor 531; the ball screw 535 is threadedly fixedly connected to the body, and the steel ball 537 inside the ball screw 535 is pressed into the groove (not shown in the figure) of the valve core 11 under the preload of the compression spring 538 inside the ball screw 535.

[0062] Under the force of the compression spring 538, the ball screw 535 ensures that the steel ball 537 is always in contact with the groove of the valve core 11, thus ensuring that the lever 534 is in continuous contact with the valve core 11, eliminating the zero-position gap, reducing the dead zone, and realizing the proportional characteristics of continuous adjustment.

[0063] The motor 531 is further provided with a stator 536; the lower end of the rotating shaft 532 is threadedly fixedly connected to the lever 534; the ball screw 535 is further provided with a threaded housing 539, and the compression spring 538 is disposed in the threaded housing 539.

[0064] For other structures of the electro-hydraulic proportional valve 50 in this embodiment, please refer to the electro-hydraulic proportional valve 10 described above.

[0065] Unlike existing technologies, the proposed electro-hydraulic proportional valve includes: a valve core; a valve sleeve fitted over the valve core; a valve body fitted over the valve sleeve and fixedly connected to it; a left end cap fitted over one end of the valve body, forming a left sensitive cavity between the valve body and the valve sleeve; a right end cap fitted over the other end of the valve body, forming a right sensitive cavity between the valve body and the valve sleeve; a drive mechanism disposed outside the valve body; and a transmission mechanism connected to both the drive mechanism and the valve core. The transmission mechanism is used to drive the valve core to rotate circumferentially relative to the valve sleeve under the drive of the drive mechanism, thereby generating a hydraulic differential between the left and right sensitive cavities. Under the action of the hydraulic differential, the valve core moves axially relative to the valve sleeve. This application's electro-hydraulic proportional valve transmits the driving force of the drive mechanism to the valve core through a transmission mechanism, causing the valve core to rotate circumferentially. This solves the problem of insufficient thrust caused by the traditional method of using a proportional electromagnet to directly drive the valve core, thus enabling high pressure and high flow rate. Furthermore, this application uses a single-stage valve core, and the valve core moves axially through the hydraulic differential between its two ends, which is equivalent to a traditional pilot-controlled electro-hydraulic proportional valve using a two-stage valve core. This simplifies the structure of the electro-hydraulic proportional valve.

[0066] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An electro-hydraulic proportional valve, characterized in that, The electro-hydraulic proportional valve includes: Valve core; A valve sleeve is fitted over the valve core. The valve body is sleeved outside the valve sleeve and is fixedly connected to the valve sleeve. A left end cap is provided on one end of the valve body and forms a left sensitive cavity between the valve body and the valve sleeve; The right end cap is installed on the other end of the valve body and forms a right sensitive cavity between the valve body and the valve sleeve; The drive mechanism is located outside the valve body; A transmission mechanism is connected to the drive mechanism and the valve core respectively. The transmission mechanism is used to drive the valve core to rotate circumferentially relative to the valve sleeve under the drive of the drive mechanism, so as to generate a hydraulic difference between the left sensitive cavity and the right sensitive cavity. Under the action of the hydraulic difference, the valve core moves axially relative to the valve sleeve. The valve body has a through hole in the middle, the valve core has a slot in the middle, the drive mechanism is arranged radially on one side of the valve body along the valve core, the transmission mechanism includes a transmission rod and a lever, one end of the transmission rod is connected to one end of the lever, the other end of the transmission rod is connected to the drive mechanism, and the other end of the lever passes through the through hole and is embedded in the slot. The lever and the transmission rod are eccentrically positioned. The transmission rod rotates under the drive of the drive mechanism. The transmission rod drives the lever to rotate around the transmission rod as the center. The lever drives the valve core to rotate circumferentially relative to the valve body. The dimension of the slot along the axial direction of the valve core is greater than the dimension of the slot along the direction perpendicular to the axial direction of the valve core and the axial direction of the transmission rod. The drive mechanism includes: Electric motor; The drive wheel is fixedly connected to the motor shaft; The driven wheel is connected to the driving wheel via a transmission, and is fixedly connected to the transmission rod; The lever includes: a body portion, which is fixedly connected to the rotating shaft of the motor; A ball screw is threadedly fixed to the main body. The steel balls inside the ball screw are pressed into the groove of the valve core by the preload of the compression spring inside the ball screw.

2. The electro-hydraulic proportional valve according to claim 1, characterized in that, The end face of the lever opposite to the valve core is provided with a slot, and the end of the transmission rod near the lever is embedded in the slot. The central axis of the slot and the central axis of the lever are arranged radially apart along the lever.

3. The electro-hydraulic proportional valve according to claim 1, characterized in that, The transmission mechanism further includes a bearing, the outer ring of which is fixedly connected to the drive mechanism, and the inner ring of which is sleeved on the transmission rod.

4. The electro-hydraulic proportional valve according to claim 1, characterized in that, The transmission ratio between the driving wheel and the driven wheel is less than 1.

5. The electro-hydraulic proportional valve according to claim 1, characterized in that, The shaft extends outside the housing of the motor.

6. The electro-hydraulic proportional valve according to claim 1, characterized in that, The valve body is provided with a left high-pressure oil port, a left working oil port, a return oil port, a right working oil port, and a right high-pressure oil port in sequence along the axial direction of the valve core, wherein the pressure of the left high-pressure oil port and the right high-pressure oil port are equal; The valve sleeve is provided with a left sensitive groove, a left high-pressure hole, a left working groove, a low-pressure groove, a right working groove, a right high-pressure hole, and a right sensitive groove in sequence along the axial direction of the valve core. The left sensitive groove is connected to the left sensitive cavity, the left high-pressure hole is connected to the left high-pressure oil port, the left working groove is connected to the left working oil port, the low-pressure groove is connected to the return oil port, the right working groove is connected to the right working oil port, the right high-pressure hole is connected to the right high-pressure oil port, and the right sensitive groove is connected to the right sensitive cavity. The valve core is provided with a low-pressure flow channel extending along its axial direction, and the low-pressure flow channel is connected to the oil return port through the low-pressure groove; one end of the valve core is provided with a left sensing high-pressure groove and a left sensing low-pressure groove, and the other end of the valve core is provided with a right sensing high-pressure groove and a right sensing low-pressure groove; wherein, the left sensing high-pressure groove is connected to the left high-pressure oil port, the left sensing low-pressure groove is connected to the low-pressure flow channel, the right sensing high-pressure groove is connected to the right high-pressure oil port, and the right sensing low-pressure groove is connected to the low-pressure flow channel.

7. The electro-hydraulic proportional valve according to claim 1, characterized in that, The electro-hydraulic proportional valve further includes: The left bearing is disposed inside the left end cover, and its outer ring is fixedly connected to the left end cover; The left spring seat has one end fixedly connected to one end of the valve core, and the other end is sleeved inside the inner ring of the left bearing; A left return spring is sleeved outside the left spring seat, with one end abutting against the left bearing and the other end abutting against the valve core; The right bearing is located inside the right end cover, and its outer ring is fixedly connected to the right end cover. The right spring seat has one end fixedly connected to the other end of the valve core, and the other end is sleeved in the inner ring of the right bearing; The right return spring is sleeved outside the right spring seat, with one end abutting against the right bearing and the other end abutting against the valve core.

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