A proportional plug-in valve driven by a direct-acting proportional directional valve

Abstract

This invention provides a proportional cartridge valve driven by a direct-acting proportional directional valve, comprising a main valve assembly and a pilot valve. The pilot valve is a 6-way direct-acting proportional directional valve with a proportional solenoid. The main valve assembly includes a valve body with a mounting plane on its side for mounting the pilot valve. A transition block is provided between the valve body and the pilot valve, the area of ​​the mounting plane of the transition block being larger than the area of ​​the mounting plane of the proportional solenoid of the pilot valve to avoid interference between the assembly of the pilot valve and the valve body. This invention, through the combination of the valve body, valve sleeve, and main valve core, along with the direct-acting proportional directional valve as the pilot valve and a displacement sensor press-fitted in the main valve core, reduces machining precision, saves production costs and processing time, and simultaneously controls product precision and valve dynamic response quality, achieving a breakthrough in the domestic low-cost two-way cartridge proportional directional valve industry.

Description

Technical Field

[0001] This utility model belongs to the field of hydraulic control valve technology, and in particular relates to a proportional cartridge valve driven by a direct-acting proportional directional valve. Background Technology

[0002] Hydraulic transmission is a transmission method that uses liquid as the working medium for energy exchange, transmission, and control. It has now become an irreplaceable and important basic technology in the modernization process of industry, agriculture, national defense, and science and technology.

[0003] Hydraulic systems typically consist of two main parts: hydraulic components (including energy components, actuators, hydraulic control components, and auxiliary components) and the working medium. Hydraulic control components come in various specifications and are widely and flexibly applied. Different combinations of hydraulic valves can form various types of hydraulic systems, and hydraulic valves play a crucial role in these systems.

[0004] In the development of hydraulic transmission and control technology, proportional control and cartridge valve technology experienced rapid development in the last two decades of the 20th century. Cartridge proportional valves, by changing the pilot stage in hydraulic control, enabled the development of hydraulic control from intermittent switching control to continuous proportional control. Based on the input electrical signal, they can continuously and proportionally control parameters such as oil pressure and flow rate.

[0005] Chinese patent document CN102913634A discloses a high-flow digital dual-closed-loop two-way cartridge-type proportional throttle valve, including a pilot stage, a main stage, and an integrated digital amplifier 8. The main stage includes a main stage valve body 12, a cartridge-type main valve sleeve 11, a main valve core 10, and a main stage valve core position sensor 16. The pilot stage is a 6-way servo proportional valve, including a pilot valve body 3, a pilot valve sleeve 4, a zero-coverage four-control-side spool valve core 5, a proportional electromagnet 6, a proportional electromagnet vent screw 7, a pilot stage valve core position sensor 9, and a pilot stage force spring 1. In the two-way cartridge-type proportional throttle valve disclosed in this patent document, the main stage valve body 12 and the cartridge-type main valve sleeve 11 in the main stage are separate structures. This separate structure of the valve body and sleeve is also a common structure in current two-way cartridge-type proportional throttle valves, which requires high precision in component processing, has high processing costs, and is difficult to maintain. Utility Model Content

[0006] To address the shortcomings of existing technologies, the purpose of this utility model is to provide an improved proportional cartridge valve driven by a direct-acting proportional directional valve.

[0007] To achieve the above objectives, the solution adopted by this utility model is as follows:

[0008] This utility model provides a proportional cartridge valve driven by a direct-acting proportional directional valve, including a main valve assembly and a pilot valve. The pilot valve is a 6-port direct-acting proportional directional valve with a proportional solenoid. The main valve assembly includes a valve body with a mounting plane on its side for mounting the pilot valve. A transition block is also provided between the valve body and the pilot valve. The area of ​​the mounting plane of the transition block is larger than the area of ​​the mounting plane of the proportional solenoid of the pilot valve to avoid interference of the assembly of the pilot valve with the valve body.

[0009] Preferably, the main valve assembly further includes a valve sleeve and an axially movable main valve core. An axially extending stepped through hole is provided in the valve body. The stepped through hole includes a distal hole, an intermediate hole, and a proximal hole. The diameters of the distal hole and the proximal hole are both larger than the diameter of the intermediate hole. The proximal end of the valve sleeve is located in the distal hole of the valve body, and the distal end of the valve sleeve extends out of the valve body. A valve core hole is provided in the valve sleeve, and the main valve core is located in the intermediate hole of the valve body and the valve core hole of the valve sleeve.

[0010] Preferably, the main valve assembly further includes a main valve core end cap disposed at the proximal end of the main valve core, a valve body end cap disposed in the proximal hole of the valve body, and a sensor end cap disposed in the proximal hole of the valve body end cap.

[0011] Preferably, the main valve assembly further includes a displacement sensor assembly, which is fixed to the valve body by the sensor end cap. The displacement sensor assembly includes a pressure-resistant sleeve fixed at one end in the sensor end cap and a core rod located in the pressure-resistant sleeve. An axially extending blind hole is provided at the proximal end of the main valve core end cap, and an axially extending through hole is provided in the sensor end cap. The bottom of the core rod of the displacement sensor assembly abuts against the blind hole of the main valve core end cap and passes through the through hole of the sensor end cap. The core rod of the displacement sensor assembly can move together with the axial movement of the main valve core.

[0012] Preferably, the system further includes an amplifier assembly and a cable connecting the amplifier assembly and the pilot valve. The amplifier assembly is fixed to the proximal end face of the valve body end cover via an amplifier connecting plate. The pressure-resistant sleeve and the protruding end of the core rod of the displacement sensor assembly are located inside the amplifier assembly, and the core rod is electrically connected to the amplifier assembly. The amplifier assembly converts the displacement signal of the main valve core sensed by the core rod of the displacement sensor assembly into an electrical signal and compares it with the input command of the direct-acting proportional directional valve of the pilot valve to form a deviation current signal, thereby performing the next step of main valve core position adjustment and controlling the movement of the main valve core to form a closed loop.

[0013] Preferably, there is a gap between the proximal end face of the valve sleeve of the main valve assembly and the step of the distal hole of the stepped through hole formed by the valve body. The intermediate hole of the stepped through hole of the valve body includes a first intermediate hole located at the proximal end and a second intermediate hole located at the distal end. The diameter of the first intermediate hole is smaller than the diameter of the second intermediate hole and is equivalent to the diameter of the valve core hole of the valve sleeve. The main valve core includes a valve core body and a stepped protrusion disposed on the valve core body. The diameter of the valve core body is equivalent to the diameter of the first intermediate hole and the valve core hole of the valve sleeve. The stepped protrusion is located in the second intermediate hole and is equivalent to the diameter of the second intermediate hole, and separates the gap between the valve body and the main valve core into a first control cavity and a second control cavity that are isolated from each other.

[0014] Preferably, the pilot valve and / or the transition block are provided with an oil inlet P, an oil outlet T, a working oil port A and a working oil port B, and the first control chamber and the second control chamber are respectively connected to the working oil port B and the working oil port A of the pilot valve and / or the transition block.

[0015] Preferably, the valve body of the main valve assembly is provided with an oil inlet P, a working oil port A, a working oil port B, two connected return oil ports T, a control oil port X, and a control oil port Y. The oil inlet P is connected to the control oil port X, the two return oil ports T are connected to the control oil port Y, the control oil ports X and Y are located on the far end face of the valve body, and the working oil ports A and B are connected to the stepped through hole of the valve body. The control oil port X on the valve body is connected to the oil inlet P of the pilot valve, and the control oil port Y on the valve body is connected to the oil outlet T of the pilot valve.

[0016] Preferably, the proximal end of the main valve core and the inner wall of the first intermediate hole of the valve body form a first contact surface; the stepped protrusion of the main valve core and the inner wall of the second intermediate hole of the valve body form a second contact surface; and the distal end of the main valve core and the inner wall of the valve core hole of the valve sleeve form a third contact surface. A first sealing ring is provided on each of the first, second, and third contact surfaces to ensure the sealing between the main valve core and the valve body and the valve sleeve in the radial direction. The first sealing ring is a Glyd ring.

[0017] Preferably, the valve body of the proportional cartridge valve is cuboid in shape, and is fixed to the valve block of the cartridge hole by four M20 mounting screws. The valve sleeve and the main valve core are inserted into the cartridge hole. A second sealing ring and a retaining ring are provided between the wall of the distal hole of the valve sleeve and the valve body, and between the wall of the valve sleeve and the cartridge hole, to ensure the sealing of the valve sleeve in the radial direction.

[0018] Beneficial effects

[0019] This utility model provides a proportional cartridge valve driven by a direct-acting proportional directional valve. Through the combination of valve body, valve sleeve and main valve core, with the direct-acting proportional directional valve as the pilot valve and the displacement sensor press-fitted in the main valve core, the machining accuracy is reduced, the installation difficulty is reduced, and the production cost and processing time are saved. At the same time, it can control the accuracy of the product and the dynamic response quality of the valve, achieving a breakthrough in the domestic low-cost two-way cartridge proportional directional valve industry. The addition of a transition block realizes the offset of the pilot valve towards the displacement sensor, solving the assembly interference problem between the proportional electromagnet of the pilot valve and the main valve part. Attached Figure Description

[0020] Figure 1 This is a three-dimensional structural diagram of the proportional cartridge valve driven by a direct-acting proportional directional valve, which relates to this utility model.

[0021] Figure 2 This is an assembly cross-sectional view of the proportional cartridge valve driven by a direct-acting proportional directional valve, which is related to this utility model.

[0022] Figure 3 This is a functional symbol diagram of a proportional cartridge valve driven by a direct-acting proportional directional valve, which relates to this utility model.

[0023] Figure 4 This is a view of the far end face of the valve body of the proportional cartridge valve driven by the direct-acting proportional directional valve involved in this utility model. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0025] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0026] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0027] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this utility model is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0028] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0029] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0030] Therefore, the following solutions are proposed:

[0031] See Figure 1-3 This utility model provides a proportional cartridge valve driven by a direct-acting proportional directional valve, including a main valve assembly 100 and a pilot valve 200.

[0032] According to the present invention, the pilot valve 200 used in the present invention is a 6-port direct-acting proportional directional valve with a proportional electromagnet.

[0033] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the main valve assembly 100 includes a valve body 110, a valve sleeve 120, a main valve core 130, a main valve core end cap 140, a valve body end cap 150, a sensor end cap 160, and a displacement sensor assembly 170, all arranged coaxially.

[0034] According to the present invention, a mounting plane is provided on the side of the valve body 110 for mounting the pilot valve 200. A transition block 300 is provided between the valve body 110 and the pilot valve 200. The area of ​​the mounting plane of the transition block 300 is larger than the area of ​​the mounting plane of the proportional electromagnet of the pilot valve 200. In this way, the interference problem caused by the proportional electromagnet in the pilot valve 200 mounted on the side of the valve body 110 to the valve body 110 can be solved.

[0035] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, a first stepped through hole 111 extending axially is provided in the valve body 110. The first stepped through hole 111 includes a distal hole 111a, an intermediate hole 111b, and a proximal hole 111c. The diameters of the distal hole 111a and the proximal hole 111c are both larger than the diameter of the intermediate hole 111b. The proximal end of the valve sleeve 120 is located in the distal hole 111a of the valve body 110, and the distal end of the valve sleeve 120 extends out of the valve body 110. A valve core hole 121 is provided in the valve sleeve 120, and the main valve core 130 is axially movable and disposed in the valve core hole 121 of the valve sleeve 120. The proximal end of the main valve core 130 extends all the way to the intermediate hole 111b of the valve body 110.

[0036] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the main valve core end cap 140 is disposed on the proximal end of the main valve core 130, the valve body end cap 150 is disposed in the proximal hole 111c of the valve body 110, the valve body end cap 150 is provided with an axially extending second stepped through hole 151, and the sensor end cap 160 is disposed in the proximal hole of the second stepped through hole 151 of the valve body end cap 150.

[0037] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the displacement sensor assembly 170 is fixed to the valve body 110 through the sensor end cap 160. Specifically, an axially extending blind hole 141 is provided at the proximal end of the main valve core end cap 140, and an axially extending through hole 161 is provided in the sensor end cap 160. The displacement sensor assembly 170 includes a pressure-resistant sleeve 171 and a core rod 172 located in the pressure-resistant sleeve 171. One end of the pressure-resistant sleeve 171 is fixed in the through hole 161 of the sensor end cap 160, and the other end extends out of the valve body 110. One end of the core rod 172 is located in the blind hole 141 of the main valve core end cap 140 and abuts against the main valve core end cap 140, and the other end passes through the through hole 161 of the sensor end cap 160 and extends out of the valve body 110. Because the core rod 172 of the displacement sensor assembly 170 abuts against the main valve core end cap 140, the core rod 172 of the displacement sensor assembly 170 can move together with the axial movement of the main valve core 130.

[0038] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the proportional cartridge valve further includes an amplifier assembly 400 and a cable 500 connecting the amplifier assembly 400 and the pilot valve 200. The amplifier assembly 400 is fixed to the proximal end face of the valve body end cover 150 through an amplifier connecting plate 180. The pressure-resistant sleeve 171 and the protruding end of the core rod 172 of the displacement sensor assembly 170 are located inside the amplifier assembly 400, and the core rod 172 is electrically connected to the amplifier assembly 400.

[0039] According to the present invention, when the main valve core 130 moves axially, the amplifier assembly 170 senses the displacement of the main valve core 130 by the core rod 172 of the displacement sensor assembly 170. The displacement of the core rod 172 is converted into a displacement electrical signal in the displacement sensor of the displacement sensor assembly 170 and transmitted to the amplifier assembly 170 in real time. Then, through the cable 500 connecting the amplifier assembly 400 and the pilot valve 200, the displacement electrical signal is compared with the input command of the direct-acting proportional directional valve of the pilot valve 200 to form a deviation current signal, thereby performing the next step of adjusting the position of the main valve core 130, thus forming a closed-loop control of the position movement of the main valve core 130, thereby improving the control accuracy of the proportional cartridge valve.

[0040] According to the present invention, the proportional cartridge valve driven by the direct-acting proportional directional valve provided by the present invention, compared with the traditional two-way cartridge proportional flow valve, uses the direct-acting proportional directional valve as the pilot valve and the displacement sensor press-fitted in the main valve core, replacing the commonly used servo proportional directional valve, which greatly reduces production costs, production difficulty, processing accuracy, processing time and installation difficulty, and saves production costs and processing time. At the same time, the combination of the simple valve body, valve sleeve and main valve core, together with the displacement sensor assembly and amplifier assembly of the main valve, can also control the accuracy of the product and the dynamic response quality of the valve, achieving a breakthrough in the domestic low-cost two-way cartridge proportional directional valve industry. At the same time, by adding a transition block between the valve body and the pilot valve, and the pilot valve adopting a V-shaped valve core, zero cover is achieved, and the pilot valve is offset towards the displacement sensor, solving the assembly interference problem between the proportional electromagnet of the pilot valve and the main valve.

[0041] Furthermore, in the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, there is a gap between the proximal end face of the valve sleeve 120 of the main valve assembly 100 and the step of the distal hole 111a of the first stepped through hole 111 of the valve body 110. The intermediate hole 111b of the first stepped through hole 111 of the valve body 110 includes a first intermediate hole located at the proximal end and a second intermediate hole located at the distal end. The diameter of the first intermediate hole is smaller than the diameter of the second intermediate hole and is close to the valve core hole of the valve sleeve 120. The diameter of 121 is approximately equal to that of the main valve core 130, which includes a valve core body 131 and a stepped protrusion 132 disposed on the valve core body 131. The diameter of the valve core body 131 is approximately equal to that of the first intermediate hole and the valve core hole 121 of the valve sleeve 120. The stepped protrusion 132 is located in the second intermediate hole and is approximately equal to that of the second intermediate hole. The stepped protrusion 132 divides the gap between the valve body 110 and the main valve core 130 into a first control cavity 112 and a second control cavity 113 that are isolated from each other.

[0042] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, an oil inlet P, an oil outlet T, a working oil port A and a working oil port B are provided on the pilot valve 200 and / or the transition block 300. The first control chamber 112 and the second control chamber 113 are respectively connected to the working oil port B and the working oil port A of the pilot valve 200 and / or the transition block 300, and two oil passages 114 are formed on the valve body 110. Two pressure measuring ports are formed on the first stepped through hole 111 of the valve body 110.

[0043] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided in this utility model, the valve body 110 of the main valve assembly 100 is provided with an oil inlet P, a working oil port A, a working oil port B, two connected return oil ports T, a control oil port X, and a control oil port Y. The oil inlet P is connected to the control oil port X, and the two return oil ports T are connected to the control oil port Y. The control oil ports X and Y are located on the far end face of the valve body 110 (in conjunction with...). Figure 1 and Figure 4 As shown), working ports A and B are connected to the first stepped through hole 111 of valve body 110, control port X on valve body 110 is connected to the inlet port P of pilot valve 200, and control port Y on valve body 110 is connected to the outlet port T of pilot valve 200.

[0044] According to the present invention, the proportional cartridge valve driven by the direct-acting proportional directional valve provided by the present invention first flows from the control port X of the valve body 110 to the inlet P of the pilot valve 200 of the pilot stage of the direct-acting proportional directional valve. When the amplifier assembly 400 for control receives the input command, it generates a continuous proportional current to drive the proportional electromagnet of the pilot valve 200, thereby pushing the valve core of the pilot valve 200 of the direct-acting proportional directional valve to move. Depending on the input electrical signal, the valve opening degree and the direction of flow of the pilot valve 200 are also different.

[0045] According to the present invention, the proportional cartridge valve driven by the direct-acting proportional directional valve provided by the present invention, when the amplifier assembly 400 receives an input command from the pilot valve 200, the pilot oil from the control port X of the valve body 110 flows through the working ports A and B of the pilot valve 200 and flows into the second control chamber 113 and the first control chamber 112 respectively through the two oil channels 114. The oil pressure of the first control chamber 112 and the second control chamber 113 acts on the upper and lower planes of the stepped protrusion 132 of the main valve core 130, thereby pushing the main valve core 130 to move axially back and forth in the valve body 110 and the valve sleeve 120, thereby opening or closing the throttle orifice formed by the cooperation of the main valve core 130 and the valve sleeve 120. As the input command changes, the opening degree of the throttle orifice also changes continuously.

[0046] According to the present invention, the proportional cartridge valve driven by the direct-acting proportional directional valve provided by the present invention has a main valve core 130 and a displacement sensor assembly 170 connected through components such as the main valve core end cap 140, the valve body end cap 150, and the sensor end cap 160. The displacement change signal is transmitted to the amplifier assembly 400 in real time and compared with the control command signal input from the pilot valve 200 to generate a deviation current signal. The current generated by the deviation signal is then transmitted to the proportional electromagnet of the pilot valve 200 through the cable 500, thereby changing the magnitude and direction of the proportional electromagnet thrust and forming a closed-loop feedback. This allows for more precise control of the oil flow rate and improves the control accuracy of the proportional cartridge valve.

[0047] Furthermore, in the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the proximal end of the main valve core 130 and the inner wall of the first intermediate hole of the valve body 110 form a first contact surface; the stepped protrusion 132 of the main valve core 130 and the inner wall of the second intermediate hole of the valve body 110 form a second contact surface; and the distal end of the main valve core 130 and the inner wall of the valve core hole 121 of the valve sleeve 120 form a third contact surface. A first sealing ring 133 is provided on each of the first, second, and third contact surfaces to ensure a seal between the main valve core 130 and the valve body 110 and the valve sleeve 120 in the radial direction. In some preferred embodiments, the first sealing ring 133 is a Glyd ring.

[0048] In the proportional cartridge valve driven by the direct-acting proportional directional valve provided by this utility model, the proportional cartridge valve of this utility model is an insert-type installation. In one embodiment, the valve body 110 of the proportional cartridge valve of this utility model is a cuboid shape (e.g., Figure 1 As shown, the valve body 110 is fixed to the valve block in the insert hole by four mounting screws 190, such as M20 screws. The valve sleeve 120 and the main valve core 130 are inserted into the insert hole. In some embodiments, a second sealing ring and a retaining ring 122 are provided between the valve sleeve 120 and the wall of the distal hole 111a of the valve body 110, and between the valve sleeve 120 and the wall of the insert hole, to ensure the valve sleeve 120 is sealed in the radial direction.

[0049] The above description is only a preferred embodiment of the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.

Claims

1. A proportional plug-in valve driven by a direct-acting proportional directional valve, characterized by, The system includes a main valve assembly and a pilot valve. The pilot valve is a 6-port direct-acting proportional directional valve with a proportional solenoid. The main valve assembly includes a valve body with a mounting plane on its side for mounting the pilot valve. A transition block is also provided between the valve body and the pilot valve. The area of ​​the mounting plane of the transition block is larger than the area of ​​the mounting plane of the proportional solenoid of the pilot valve to avoid interference of the assembly of the pilot valve with the valve body.

2. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 1, characterized in that, The main valve assembly further includes a valve sleeve and an axially movable main valve core. An axially extending stepped through hole is provided in the valve body. The stepped through hole includes a distal hole, an intermediate hole, and a proximal hole. The diameters of the distal hole and the proximal hole are both larger than the diameter of the intermediate hole. The proximal end of the valve sleeve is located in the distal hole of the valve body, and the distal end of the valve sleeve extends out of the valve body. A valve core hole is provided in the valve sleeve. The main valve core is located in the intermediate hole of the valve body and the valve core hole of the valve sleeve.

3. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 2, characterized in that, The main valve assembly also includes a main valve core end cap located at the proximal end of the main valve core, a valve body end cap located in the proximal hole of the valve body, and a sensor end cap located in the proximal hole of the valve body end cap.

4. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 3, characterized in that, The main valve assembly also includes a displacement sensor assembly, which is fixed to the valve body by the sensor end cap. The displacement sensor assembly includes a pressure-resistant sleeve fixed at one end in the sensor end cap and a core rod located in the pressure-resistant sleeve. An axially extending blind hole is provided at the proximal end of the main valve core end cap, and an axially extending through hole is provided in the sensor end cap. The bottom of the core rod of the displacement sensor assembly abuts against the blind hole of the main valve core end cap and passes through the through hole of the sensor end cap. The core rod of the displacement sensor assembly can move together with the axial movement of the main valve core.

5. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 4, characterized in that, It also includes an amplifier assembly and a cable connecting the amplifier assembly and the pilot valve. The amplifier assembly is fixed to the proximal end face of the valve body end cover by an amplifier connecting plate. The pressure-resistant sleeve and the protruding end of the core rod of the displacement sensor assembly are located inside the amplifier assembly, and the core rod is electrically connected to the amplifier assembly. The amplifier assembly converts the displacement signal of the main valve core sensed by the core rod of the displacement sensor assembly into an electrical signal, and compares it with the input command of the direct-acting proportional directional valve of the pilot valve to form a deviation current signal, thereby performing the next step of main valve core position adjustment and controlling the movement of the main valve core to form a closed loop.

6. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 2, characterized in that, There is a gap between the proximal end face of the valve sleeve of the main valve assembly and the step of the distal hole of the stepped through hole formed by the valve body. The intermediate hole of the stepped through hole of the valve body includes a first intermediate hole located at the proximal end and a second intermediate hole located at the distal end. The diameter of the first intermediate hole is smaller than the diameter of the second intermediate hole and is equivalent to the diameter of the valve core hole of the valve sleeve. The main valve core includes a valve core body and a stepped protrusion disposed on the valve core body. The diameter of the valve core body is equivalent to the diameter of the first intermediate hole and the valve core hole of the valve sleeve. The stepped protrusion is located in the second intermediate hole and is equivalent to the diameter of the second intermediate hole, and separates the gap between the valve body and the main valve core into a first control cavity and a second control cavity that are isolated from each other.

7. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 6, characterized in that, The pilot valve and / or the transition block are provided with an oil inlet P, an oil outlet T, a working oil port A and a working oil port B, and the first control chamber and the second control chamber are respectively connected to the working oil port B and the working oil port A of the pilot valve and / or the transition block.

8. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 7, characterized in that, The main valve assembly has an oil inlet P, a working oil inlet A, a working oil inlet B, two connected return oil inlets T, a control oil inlet X, and a control oil inlet Y on its valve body. The oil inlet P is connected to the control oil inlet X, and the two return oil inlets T are connected to the control oil inlet Y. The control oil inlets X and Y are located on the far end face of the valve body. The working oil inlets A and B are connected to the stepped through hole of the valve body. The control oil inlet X on the valve body is connected to the oil inlet P of the pilot valve, and the control oil inlet Y on the valve body is connected to the oil outlet T of the pilot valve.

9. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 6, characterized in that, The proximal end of the main valve core and the inner wall of the first intermediate hole of the valve body form a first contact surface; the stepped protrusion of the main valve core and the inner wall of the second intermediate hole of the valve body form a second contact surface; and the distal end of the main valve core and the inner wall of the valve core hole of the valve sleeve form a third contact surface. A first sealing ring is provided on each of the first, second, and third contact surfaces to ensure the sealing between the main valve core and the valve body and the valve sleeve in the radial direction. The first sealing ring is a Glyd ring.

10. The proportional cartridge valve driven by a direct-acting proportional directional valve according to claim 2, characterized in that, The proportional cartridge valve has a cuboid body, which is fixed to the valve block in the cartridge hole by four M20 mounting screws. The valve sleeve and the main valve core are inserted into the cartridge hole. A second sealing ring and a retaining ring are provided between the wall of the distal hole of the valve sleeve and the wall of the cartridge hole, and between the valve sleeve and the wall of the cartridge hole, to ensure the sealing of the valve sleeve in the radial direction.

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