Half-bridge pilot control follow-up pressure compensation proportional valve
By using a half-bridge pilot-controlled follow-up pressure compensation proportional valve, the problems of low response frequency and wear of the existing electro-hydraulic lifter's lowering valve are solved, achieving precise control and high-frequency response of agricultural machinery.
Patent Information
- Application Number
- CN202512049235.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-02-27
AI Technical Summary
The existing electro-hydraulic lifters mainly use mechanical one-way valve structures for their lowering valves, which cannot achieve pilot control, have low response frequency, and are prone to wear, thus failing to achieve precise lowering of agricultural implements.
The valve adopts a half-bridge pilot control follow-up pressure compensation proportional valve, which includes a lowering valve body, a lowering valve core, a pilot valve core and a proportional electromagnet. Through the cooperation of the pilot valve core and the lowering valve core, proportional control and high-precision pressure stabilization are achieved. It is equipped with an anti-shock device to reduce valve core wear.
It achieves a precise reduction in the proportion of agricultural machinery, a high response frequency, reduces valve core wear, and improves control accuracy and response frequency.
Smart Images
Figure CN121576323A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a proportional valve, and more particularly to a half-bridge pilot-controlled follow-up pressure-compensated proportional valve. Background Technology
[0002] The electro-hydraulic lifter is a core component of the hydraulic system of agricultural machinery. It comprises an ascending valve and a descending valve, both driven by proportional electromagnets. The ascending valve controls the flow direction of hydraulic oil, thus raising the implement; the descending valve controls the flow direction of hydraulic oil, thus lowering the implement. Currently, existing descending valves used in electro-hydraulic lifters primarily employ a mechanical one-way valve structure. Their function is relatively simple; although they have a push rod, they cannot achieve pilot control and can only be mechanically controlled. Furthermore, the low response frequency of mechanical control makes it prone to wear on the main valve stem and results in high operating resistance. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a half-bridge pilot control follow-up pressure compensation proportional valve that can better control the precise descent of agricultural machinery.
[0004] To solve the above-mentioned technical problems, the technical solution of the present invention is: a half-bridge pilot-controlled follow-up pressure-compensated proportional valve, characterized in that: it includes a descending valve body, a descending valve core, a pilot valve core, a pilot valve core connecting device, and a proportional electromagnet; The descending valve body is provided with a descending valve inlet and a descending valve outlet. The descending valve core is slidably disposed in the descending valve body. A main valve core sealing valve port is formed at the mating surface between the descending valve core and the descending valve body to connect or disconnect the descending valve inlet and the descending valve outlet. A main valve core throttling port is provided at one end of the descending valve core corresponding to the descending valve outlet side. When the descending valve core slides toward the end away from the main valve core throttling port, the main valve core sealing valve port and the main valve core throttling port gradually become larger. The pilot valve core is slidably disposed inside the descending valve core, and a pilot sealing valve port is formed at the mating surface of the pilot valve core and the descending valve core. One side of the pilot sealing valve port is provided with a pilot oil outlet ring groove communicating with the outlet of the descending valve, and the other side of the pilot sealing valve port is provided with a pilot half-bridge throttling port. When the pilot valve core slides toward the end away from the throttling port of the main valve core, the pilot sealing valve port and the pilot half-bridge throttling port gradually become larger. The lowering valve core is also provided with a pilot half-bridge annular groove that is connected to or disconnected from the pilot half-bridge throttling port. The pilot half-bridge annular groove is connected to the lowering valve inlet through the main valve pilot throttling orifice. The pilot half-bridge annular groove is also connected to the outer end of the lowering valve core through the main valve control oil passage.
[0005] As a preferred technical solution, the pilot valve core connecting device includes an adjusting screw sleeve, a spring seat, and an adjusting spring. The adjusting screw sleeve is fixed in the lowering valve body, and the adjusting spring is fitted outside the pilot valve core, with its two ends abutting against the adjusting screw sleeve and the spring seat, respectively.
[0006] As a preferred technical solution, the outer periphery of the adjusting screw sleeve is provided with adjusting conical teeth, the outlet of the lowering valve is an oblique oil return hole, and the position of the adjusting conical teeth corresponds to that of the oblique oil return hole.
[0007] As a preferred technical solution, the lowering valve body is provided with a locking structure for positioning the adjusting screw sleeve.
[0008] As a preferred technical solution, a plug is installed at the end of the descending valve core away from the throttling orifice of the main valve core.
[0009] As a preferred technical solution, a plug is installed at the end of the descending valve core away from the throttling orifice of the main valve core, and the plug is provided with an anti-impact device.
[0010] As a preferred technical solution, the anti-impact device includes an anti-impact valve body, a disc spring, and a support base. The anti-impact valve body is slidably installed in the sealing cavity inside the plug. The support base is installed on the anti-impact valve body and a disc spring is provided between the support base and the anti-impact valve body. The cross-sectional area of the end piston structure of the anti-impact valve body is smaller than the cross-sectional area of the sealing cavity.
[0011] As a preferred technical solution, the anti-impact valve body is also provided with an oil replenishing check valve that replenishes oil towards the sealed cavity, and small oil drain holes are distributed on the outer periphery of the anti-impact valve body.
[0012] As a preferred technical solution, the main valve core sealing valve port is located between the outer conical surface of the descending valve core and the inner conical surface of the valve body, the pilot sealing valve port is located between the outer conical surface of the pilot valve core and the inner conical surface of the descending valve core, and the main valve core sealing valve port and the pilot sealing valve port are coaxially arranged.
[0013] As a preferred technical solution, the first-out oil ring groove is a cylindrical annular cavity located between the lowering valve core and the pilot valve core.
[0014] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: The proportional valve of this application, as a descending valve, can achieve proportional control and high-precision pressure stabilization, has a high response frequency, and the proportional pilot position can follow the speed adjustment of the pressure compensation throttle valve, which can better control the precise descending of agricultural machinery; at the same time, it has an anti-impact device to reduce the influence of lateral force on the valve core, reduce the wear of the valve core, and ensure a high response frequency. Attached Figure Description
[0015] The following figures are intended only to illustrate and explain the present invention and do not limit the scope of the invention. Wherein: Figure 1 This is an installation diagram of Embodiment 1 of the present invention; Figure 2 This is a structural schematic diagram of Embodiment 1 of the present invention; Figure 3 This is the principle of Embodiment 1 of the present invention. Figure 1 ; Figure 4 This is the principle of Embodiment 1 of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the control state one of the half-bridge oil circuit in an embodiment of the present invention; Figure 6 This is a schematic diagram of the control state two of the half-bridge hydraulic circuit in an embodiment of the present invention; Figure 7 This is a schematic diagram of the control state three of the half-bridge oil circuit in an embodiment of the present invention; Figure 8 This is a schematic diagram of the control state four of the half-bridge oil circuit in an embodiment of the present invention; Figure 9 This is a schematic diagram of the current regulation structure according to Embodiment 1 of the present invention; Figure 10 This is a schematic diagram of the voltage stabilizing structure according to Embodiment 1 of the present invention; Figure 11 This is a schematic diagram of the anti-impact device according to Embodiment 1 of the present invention; Figure 12 This is a schematic diagram of the anti-impact device according to Embodiment 2 of the present invention; Figure 13 This is a schematic diagram of the structure of Embodiment 3 of the present invention; Figure 14 This is the principle of Embodiment 3 of the present invention. Figure 1 ; Figure 15 This is the principle of Embodiment 3 of the present invention. Figure 2 ; In the diagram: 1-Lowering valve body; 2-Lowering valve core; 3-Pilot valve core; 4-Proportional electromagnet; 5-Pressure control chamber; 6-Lowering valve inlet; 7-Lowering valve outlet; 8-Main valve core sealing port; 9-Main valve core throttling port; 10-Pilot sealing port; 11-Pilot outlet oil ring groove; 12-Pilot half-bridge throttling port; 13-Pilot half-bridge ring groove; 14-Main valve pilot throttling orifice; 15-Main valve control oil passage; 16-Adjusting screw sleeve; 17-Spring seat; 18-Adjusting spring; 19-Adjusting bevel gear; 20-Small bevel gear key; 21-Plug; 22-Anti-impact valve body; 23-Piston structure; 24-Disc spring; 25-Support seat; 26-Sealing chamber; 27-Replenishing check valve; 28-Drainage orifice; 29-Locking structure; 30-Cylindrical ring cavity two; 31-Pressure sensing hole one; 32-Pressure sensing hole two. Detailed Implementation
[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the following detailed description, only certain exemplary embodiments of the invention are described by way of illustration. Undoubtedly, those skilled in the art will recognize that various modifications can be made to the described embodiments without departing from the spirit and scope of the invention. Therefore, the drawings and description are illustrative in nature and not intended to limit the scope of the claims.
[0017] See Figures 1 to 4 The half-bridge pilot-controlled follow-up pressure-compensated proportional valve includes a lowering valve body 1, a lowering valve core 2, a pilot valve core 3, a pilot valve core connecting device, and a proportional electromagnet 4.
[0018] Figure 1 This is a schematic diagram of the proportional valve installed on the valve seat. The proportional valve is inserted as a whole from one side of the valve seat, and a pressure control chamber 5 is formed between the end of the proportional valve and the valve seat. The pressure control chamber 5 is a key influencing factor in controlling the opening and closing action of the descending valve core 2.
[0019] See Figure 1 The lowering valve body 1 is provided with a lowering valve inlet 6 and a lowering valve outlet 7. The lowering valve inlet 6 is connected to the oil inlet of the valve seat, and the lowering valve outlet 7 is connected to the oil outlet of the valve seat.
[0020] See Figure 2 The lowering valve core 2 is slidably disposed within the lowering valve body 1. A main valve core sealing valve port 8 is formed at the mating surface between the lowering valve core 2 and the lowering valve body 1, which connects or cuts off the lowering valve inlet 6 and the lowering valve outlet 7, corresponding to the side of the lowering valve outlet 7. Figure 2The lowering valve core 2 (left side) has a main valve core throttling port 9 at one end. An annular groove connecting the main valve core sealing port 8 and the main valve core throttling port 9 is also provided on the outer periphery of the lowering valve core 2. The lowering valve core 2 faces away from the main valve core throttling port 9. Figure 2 When the valve core slides (on the right side), the sealing valve port 8 and the throttling port 9 of the main valve core gradually increase in size.
[0021] The pilot valve core 3 is slidably disposed within the descending valve core 2. A pilot sealing valve port 10 is formed at the mating surface of the pilot valve core 3 and the descending valve core 2. One side of the pilot sealing valve port 10 is provided with a pilot oil outlet annular groove 11 communicating with the descending valve outlet 7. The other side of the pilot sealing valve port 10 is provided with a pilot half-bridge throttling port 12. An annular groove communicating between the pilot sealing valve port 10 and the pilot half-bridge throttling port 12 is also provided on the outer periphery of the pilot valve core 3. The pilot valve core 3 faces the end away from the main valve core throttling port 9. Figure 2 When the pilot sealing valve port 10 and the pilot half-bridge throttling port 12 slide (on the right side of the valve), they gradually increase in size.
[0022] The lowering valve core 2 is also provided with a pilot half-bridge annular groove 13 that is connected to or disconnected from the pilot half-bridge throttling port 12. The pilot half-bridge annular groove 13 is connected to the lowering valve inlet 6 through the main valve pilot throttling hole 14. The pilot half-bridge annular groove 13 is also connected to the outer end of the lowering valve core 2 through the main valve control oil passage 15.
[0023] The descending valve body 1, descending valve core 2, and pilot valve core 3 are arranged coaxially. The main valve core sealing port 8 and the pilot sealing port 10 are arranged coaxially. Since the descending valve body 1 is axially mounted on the valve seat and is coaxial with the main valve core sealing port 8 and the pilot sealing port 10, the three structures form a three-stage coaxial structure when the main valve is closed.
[0024] The descending valve body 1 and the descending valve core 2 form a two-stage concentric guiding structure throughout the entire flow regulation stroke, providing a structural basis for high-precision linear control of the main throttling orifice flow.
[0025] The main valve core sealing port 8 is located between the outer conical surface of the descending valve core and the inner conical surface of the valve body. The outer conical surface of the descending valve core is located on the descending valve core 2, and the inner conical surface of the valve body is located on the valve body. The opening size of the outer conical surface of the descending valve core and the inner conical surface of the valve body is the opening size of the main valve core sealing port 8.
[0026] The pilot sealing valve port 10 is located between the outer conical surface of the pilot valve core and the inner conical surface of the descending valve core. The outer conical surface of the pilot valve core is located on the pilot valve core 3, and the inner conical surface of the descending valve core is located on the descending valve core 2. The opening size of the outer conical surface of the pilot valve core and the inner conical surface of the descending valve core is the opening size of the pilot sealing valve port 10.
[0027] The control principle of the half-bridge hydraulic circuit is as follows: When the oil inlet 6 of the downcomer valve passes through the pilot throttle orifice 14 of the main valve, it enters the closed annular space of the main pilot half-bridge annular groove 13. Initially, this space is closed because the outer conical surface of the pilot valve core contacts the inner conical surface of the downcomer valve core (i.e., the pilot sealing valve port 10 is closed). Therefore, the oil in the pilot half-bridge annular groove 13 can only enter the pressure control chamber 5 of the downcomer valve core 2 through the main valve control oil passage 15. Under the action of the oil pressure at the downcomer valve inlet 6, a force is applied to the left of the downcomer valve core 2 (see...). Figure 5 middle Ensure that the lowering valve core 2 is closed. See the status diagram. Figure 5 ; When the proportional electromagnet 4 is energized and a certain current flows through it, the pin actuates accordingly, and the pilot valve core 3 moves to the right to open by a certain degree (see...). Figure 6 middle At this point, both the pilot half-bridge throttle port 12 and the pilot sealing valve port 10 are open, and the pilot half-bridge annular groove 13 is no longer closed. Instead, a certain amount of oil releases pressure through the pilot half-bridge throttle port 12 and the pilot sealing valve port 10, causing the pressure control chamber 5 of the descending valve core 2 to decrease. See the status section. Figure 6 ; As the pressure in pressure control chamber 5 decreases, the lowering valve core 2 moves to the right and gradually opens (see...). Figure 7 middle When the main valve core throttle port 9 of the lowering valve core 2 is activated, the lowering valve core 2 will shift to the right, causing the opened pilot half-bridge throttle port 12 and pilot sealing valve port 10 to decrease in size. The reduced size of the pilot half-bridge throttle port 12 will cause more pressure oil to enter the pressure control chamber 5 of the lowering valve core 2 through the main valve control oil passage 15. See the status section. Figure 7 ; As the pressure in the pressure control chamber 5 of the descending valve core 2 gradually increases, it pushes the descending valve core 2 to move to the left (see...). Figure 8 middle (), reduce the main valve core throttling orifice 9, increase the pilot half-bridge throttling orifice 12, see [reference]. Figure 8 The above actions continue in a cycle until they reach a stable state. When a certain input current corresponds to the corresponding throttling opening of the valve core 2, this is the principle of speed regulation of the proportional pilot position follow-up pressure compensation throttling valve.
[0028] The principle of pressure compensation is as follows: During the operation of the proportional electromagnet 4, when the pressure at the inlet 6 of the lowering valve suddenly increases, the flow rate through the main valve core throttling orifice 9 increases due to the pressure difference. Because the pressure response of the pressure control chamber 5 is delayed, the lowering valve core 2 moves to the right, and the flow rate at the main valve core throttling orifice 9 increases again. Subsequently, as the lowering valve core 2 moves to the right, the pilot sealing valve orifice 10 closes. As the pilot sealing valve orifice 10 closes, the pressure in the pressure control chamber 5 increases. At the same time, as the inlet pressure increases, the pressure through the pilot half-bridge throttling orifice 12 also increases. The lowering valve core 2 moves to the left, and the main valve core throttling orifice 9 also decreases, thereby keeping the flow rate through the main valve core sealing valve orifice 8 constant, thus forming a pressure compensation and flow stabilization effect.
[0029] Similarly, when the pressure at the inlet 6 of the lowering valve suddenly decreases, the flow rate through the throttling port 9 of the main valve core decreases. Due to the lag in the pressure response of the pressure control chamber 5, the lowering valve core 2 moves to the left, further reducing the flow rate at the throttling port 9 of the main valve core. As the opening of the sealing port 8 of the main valve core decreases, the pilot sealing port 10 increases. At this time, due to the effect of hydraulic resistance, the pressure entering the pressure control chamber 5 from the inlet 6 of the lowering valve also decreases. Therefore, the lowering valve core 2 moves to the right to increase the throttling port area, thereby maintaining the flow rate through the sealing port 8 of the main valve core unchanged, demonstrating the effect of pressure compensation.
[0030] See Figure 9 The pilot valve core connecting device includes an adjusting screw sleeve 16, a spring seat 17, and an adjusting spring 18. The adjusting screw sleeve 16 is fixed inside the lowering valve body 1. The adjusting spring 18 is fitted outside the pilot valve core 3, with its two ends abutting against the adjusting screw sleeve 16 and the spring seat 17, respectively. The spring seat 17 is installed on the left end of the pilot valve core 3 by a snap ring. The lowering valve body is provided with a locking structure 29 for positioning the adjusting screw sleeve 16. The locking structure 29 locks the adjusting screw sleeve 16 in the radial direction. After adjusting the axial position, it is tightened to fix the adjusting screw sleeve 16 and prevent further displacement.
[0031] The adjusting screw sleeve 16 has adjusting bevel teeth 19 on its outer periphery, and the outlet 7 of the lowering valve is an oblique return oil hole. The adjusting bevel teeth 19 and the oblique return oil hole are positioned correspondingly. When it is necessary to adjust the preload, the small bevel gear key 20 is used. Through the oblique return oil hole of the lowering valve body 1, the small bevel gear key 20 engages with the adjusting bevel teeth 19 at the outer end of the adjusting screw sleeve 16. Rotating the small bevel gear key 20 drives the adjusting screw sleeve 16 to rotate, changing the preload of the adjusting spring 18, and thus adjusting the magnitude of the initial current.
[0032] The end face of the adjusting screw sleeve 16 is parallel to the end face of the descending valve core 2. The end face of the adjusting bevel tooth 19 of the adjusting screw sleeve 16 is relatively short from the end face of the spring seat 17. The end face of the main valve core throttling port 9 is relatively long from the pilot sealing valve port 10 and the main valve core sealing valve port 8. With this design, eddy current areas or unstable flow areas are basically not formed throughout the entire stroke range of the descending valve core 2, which is conducive to the stability of the environmental pressure field at the spring end of the pilot valve core 3.
[0033] See Figure 10 The first oil outlet groove 11 is a cylindrical annular cavity 1 located between the descending valve core 2 and the pilot valve core 3. This cylindrical annular cavity 1 serves as the main pressure-stabilizing structure, its functions being: firstly, to ensure a stable outflow of the pilot valve's regulated flow; and secondly, to isolate the influence of unstable pressure caused by the variable flow rate through the main throttling region of the descending valve core 2 and the descending valve body 1 on the control of the pilot valve core 3. To further provide a stable pressure environment, a second cylindrical annular cavity 30 is provided between the pilot valve core 3 and the adjusting sleeve 16. This cylindrical annular cavity structure isolates the unstable pressure caused by the variable flow rate through the main throttling region of the descending valve core 2 and the descending valve body 1, keeping the pressure at the spring seat 17 in a relatively stable state. These two cylindrical annular cavity structures constitute a stable pressure environment in the pilot valve core 3 region, laying the foundation for high-precision pilot control. The surface of the pilot valve core 3 is also provided with two pilot valve core pressure sensing holes, namely pressure sensing hole one 31 and pressure sensing hole two 32. The pressure sensing hole one 31 and pressure sensing hole two 32 correspond to the positions of cylindrical annular cavity one and cylindrical annular cavity two 30, respectively, and are located in the stable pressure area of the two pressure stabilizing structures, so as to realize a high-precision stable pressure environment controlled by the pilot valve core 3.
[0034] The proportional electromagnet 4 is installed at one end of the pilot valve core 3 and is coaxially threaded to the lowering valve body 1, forming a precise positioning with the threaded end face.
[0035] The descending valve body 1 and the descending valve core 2 form a two-stage concentric guiding structure throughout the entire flow regulation stroke, providing a structural basis for high-precision linear control of the flow at the main valve core throttling port 9.
[0036] The main valve core throttling port 9 adopts a symmetrical non-axial design, which can realize high-precision linear control of small flow rate.
[0037] See Figure 11 A plug 21 is installed at the end of the lowering valve core 2 away from the throttling port 9 of the main valve core, and the plug 21 is equipped with an anti-impact device. When the lowering valve core 2 is not open, if the pressure suddenly increases, the anti-impact device can relieve the increased pressure by opening the lowering valve core 2, reducing the impact on the lateral force of the valve core, reducing the wear of the valve core, and ensuring a high response frequency.
[0038] The anti-impact device includes an anti-impact valve body 22, a piston structure 23 integrally mounted on the end of the anti-impact valve body 22, a disc spring 24, and a support seat 25. The anti-impact valve body 22 is slidably installed within the sealing cavity 26 of the plug 21. The piston structure 23 is correspondingly located at a small opening outside the plug. The support seat 25 is mounted on the anti-impact valve body 22, and a disc spring 24 is provided between the support seat 25 and the anti-impact valve body 22. The cross-sectional area of the piston structure 23 is smaller than the cross-sectional area of the sealing cavity 26. The anti-impact valve body 22 also has a one-way oil replenishment valve 27 for replenishing oil into the sealing cavity 26, and small oil drain holes 28 are distributed on the outer periphery of the anti-impact valve body 22.
[0039] The anti-surge principle is as follows: When an abnormally high pressure occurs at the inlet 6 of the descending valve, the pressure control chamber 5 of the descending valve core 2 experiences a pressure exceeding the set pressure threshold. In this case, the end piston structure 23 of the anti-surge valve body 22 is displaced under stress and connects to the sealing chamber 26, allowing pressurized oil to enter. Since the cross-sectional area of the sealing chamber 26 is larger than that of the end piston structure 23 of the anti-surge valve body 22, the anti-surge valve body 22 will continue to open under low pressure when the pressure decreases. Simultaneously, the descending valve core 2 will open due to the lower pressure in the pressure control chamber 5, opening the main valve core throttle port 9 to release pressure. When the pressure is released to a safe value, the anti-surge valve body 22 closes, and then the descending valve core 2 closes. The oil replenishment check valve 27 is used to replenish oil to the sealing chamber 26 during the opening of the anti-surge valve body 22, while ensuring no leakage in the pressure control chamber 5 under normal pressure. The oil drain hole 28 is used to drain oil when the sealing chamber 26 is closed. The function of disc spring 24 is to reset the anti-impact device after it has shifted to the left. It can also be a spring structure.
[0040] Example 2: This embodiment is basically the same in structure as Embodiment 1, the main difference being the end face shape of the anti-impact valve body 22 and the number of disc springs 24. See [link to previous embodiment]. Figure 12 Their impact resistance principle is the same, so it will not be elaborated here.
[0041] Example 3: Both Embodiment 1 and Embodiment 2 include an anti-impact device, but Embodiment 3 does not. A plug 21 is installed at the end of the descending valve core 2 furthest from the main valve core throttling orifice 9. See [link to documentation] for structure and principle. Figures 13 to 15 Except for the lack of impact protection, the working principle of this embodiment is exactly the same as that of Embodiment 1, and will not be repeated here.
[0042] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.
Claims
1. A half-bridge pilot-controlled follow-up pressure-compensated proportional valve, characterized in that: It includes a lowering valve body, a lowering valve core, a pilot valve core, a pilot valve core connecting device, and a proportional electromagnet; The descending valve body is provided with a descending valve inlet and a descending valve outlet. The descending valve core is slidably disposed in the descending valve body. A main valve core sealing valve port is formed at the mating surface between the descending valve core and the descending valve body to connect or cut off the descending valve inlet and the descending valve outlet. A main valve core throttling port is provided at one end of the descending valve core corresponding to the descending valve outlet side. When the descending valve core slides toward the end away from the main valve core throttling port, the main valve core sealing valve port and the main valve core throttling port gradually become larger. The pilot valve core is slidably disposed inside the descending valve core, and a pilot sealing valve port is formed at the mating surface of the pilot valve core and the descending valve core. One side of the pilot sealing valve port is provided with a pilot oil outlet ring groove communicating with the outlet of the descending valve, and the other side of the pilot sealing valve port is provided with a pilot half-bridge throttling port. When the pilot valve core slides toward the end away from the throttling port of the main valve core, the pilot sealing valve port and the pilot half-bridge throttling port gradually become larger. The lowering valve core is also provided with a pilot half-bridge annular groove that is connected to or disconnected from the pilot half-bridge throttling port. The pilot half-bridge annular groove is connected to the lowering valve inlet through the main valve pilot throttling orifice. The pilot half-bridge annular groove is also connected to the outer end of the lowering valve core through the main valve control oil passage.
2. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 1, characterized in that: The pilot valve core connecting device includes an adjusting screw sleeve, a spring seat, and an adjusting spring. The adjusting screw sleeve is fixed in the lowering valve body, and the adjusting spring is fitted outside the pilot valve core, with its two ends abutting against the adjusting screw sleeve and the spring seat, respectively.
3. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 2, characterized in that: The outer circumference of the adjusting screw sleeve is provided with adjusting conical teeth, and the outlet of the lowering valve is an oblique oil return hole. The position of the adjusting conical teeth corresponds to that of the oblique oil return hole.
4. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 2, characterized in that: The lowering valve body is provided with a locking structure for positioning the adjusting screw sleeve.
5. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 1, characterized in that: A plug is installed at the end of the descending valve core away from the throttling orifice of the main valve core.
6. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 1, characterized in that: A plug is installed at the end of the descending valve core away from the throttling orifice of the main valve core, and the plug is equipped with an anti-impact device.
7. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 6, characterized in that: The anti-impact device includes an anti-impact valve body, a disc spring, and a support base. The anti-impact valve body is slidably installed in the sealing cavity inside the plug. The support base is installed on the anti-impact valve body and a disc spring is provided between the support base and the anti-impact valve body. The cross-sectional area of the end piston structure of the anti-impact valve body is smaller than the cross-sectional area of the sealing cavity.
8. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 7, characterized in that: The anti-impact valve body is also provided with an oil replenishment check valve that replenishes oil into the sealed cavity, and small oil drain holes are distributed on the outer periphery of the anti-impact valve body.
9. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 1, characterized in that: The main valve core sealing port is located between the outer conical surface of the descending valve core and the inner conical surface of the valve body, and the pilot sealing port is located between the outer conical surface of the pilot valve core and the inner conical surface of the descending valve core. The main valve core sealing port and the pilot sealing port are coaxially arranged.
10. The half-bridge pilot-controlled follow-up pressure-compensated proportional valve as described in claim 1, characterized in that: The pilot oil ring groove is a cylindrical annular cavity located between the descending valve core and the pilot valve core.