Three-stage pilot inverse proportional pressure reducing solenoid valve

Abstract

The present invention relates to a solenoid valve, and more specifically to a three-stage pilot-operated inverse proportional pressure reducing solenoid valve. It solves the shortcomings of conventional high-pressure, high-flow proportional solenoid valves for suspension systems, where the plate-type relief valve structure is unstable due to vibration, and the structure of the electromagnetic drive unit is complex, posing a risk of product failure due to internal leakage. This three-stage pilot-operated inverse proportional pressure reducing solenoid valve employs a spool-type pilot valve structure, integrating the second radially outward convex ring and the ejector rod into a single component (three-stage spool). When the three-stage spool moves, both ends are supported by bearings in the stop iron and the inner bore of the guide cylinder, forming a stable double support structure and preventing contact friction problems caused by eccentricity between the three-stage spool and the valve body.

Description

Technical Field

[0001] The present invention relates to a solenoid valve, specifically to a three-stage pilot proportional pressure reducing solenoid valve.

Background Art

[0002] The three-stage pilot proportional pressure reducing solenoid valve (VFS) is commonly used in high-pressure large-flow precision fluid pressure control systems. It includes an electromagnetic control unit, which adjusts the internal mechanical structure according to the change of an electrical signal to achieve precise pressure control. The first stage is usually a small pilot valve, which controls the second stage, and the second stage controls the third stage again, and finally reaches the main valve to achieve precise pressure adjustment. This multi-stage pilot design can improve the response speed and accuracy of the valve, and is especially suitable for systems that require very fine pressure adjustment, such as automated control systems and precision hydraulic systems.

[0003] In the Orling type three-stage pilot proportional pressure reducing solenoid valve, the operating pressure of the main valve is high and the pressure acting surface is large, so it is often insufficient to directly control the main valve with a single electromagnetic force. Therefore, this design adopts a three-stage pilot amplification structure to enhance the control force and accuracy.

[0004] The first-stage pilot valve adopts a spool valve structure, and both the second-stage pilot valve and the third-stage pilot valve adopt a plate-type relief valve structure, which is used to control or limit the fluid pressure so that the internal pressure reaches the set value, and is suitable for cases where precise control is required.

[0005] In plate relief valves, a plate or spool moves in response to fluid pressure to control the flow rate or pressure of the fluid. Such movement can cause vibrations in the valve structure, and dynamic fluid changes (such as fluctuations in flow velocity or pressure) further affect these vibrations, forming a complex coupled vibration system. This also introduces coupled vibration problems inherent to plate relief valve structures, and when coupled vibrations occur, the regulating effect of the solenoid valve is significantly reduced. In suspension systems, valves are typically required to respond to dynamic load changes at high speeds, meaning the valves need to operate stably at high frequencies, and the mechanical structure itself (e.g., plate relief valves) cannot effectively suppress or isolate high-frequency vibrations caused by dynamic fluid changes. Furthermore, in plate relief valves, the available space and design options for increasing damping or isolating vibrations are very limited, restricting the possibility of achieving effective vibration control in high-frequency applications.

[0006] The Austin-type three-stage pilot-operated inverse proportional pressure reducing solenoid valve employs a structure with a demagnetizing ring weld in the electromagnetic drive unit. While it can be used when the suspension system pressure is 30 MPa or higher, it increases product costs due to welding and airtightness testing, and there is a possibility of internal leakage due to welding defects. [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to solve the shortcomings of conventional high-pressure, high-flow proportional solenoid valves for suspension systems, namely that the plate-type relief valve structure is vibrationally unstable and the electromagnetic drive unit has a complex structure that may lead to product failure due to internal leakage, and to provide a three-stage pilot-operated inverse proportional pressure reducing solenoid valve. [Means for solving the problem]

[0008] The present invention provides the following technical solutions to address the shortcomings of the prior art described above.

[0009] A three-stage pilot-operated inverse proportional pressure reducing solenoid valve comprising a yoke and a stop iron assembly, The yoke is annular, and a valve body assembly and a coil assembly are provided at both ends of the yoke, respectively, and a first cavity is formed between the valve body assembly, the yoke, and the coil assembly. The valve assembly comprises an annular valve body, a single-stage spool assembly, and a main spring, and the valve body is provided with a plurality of first radial through holes uniformly arranged circumferentially in the radial direction. The stop iron assembly comprises a stop iron and a small spring. The stop iron is located within the first cavity, and a flow path gap is provided between the outer wall of one end of the stop iron near the valve body and the inner wall of the first cavity. The stop iron is provided with a first axial blind hole that opens axially toward the valve body, and within the first axial blind hole, a two-stage spool, a three-stage spool, and an armature are arranged in order from the outside to the inside in the axial direction. The two-stage spool comprises an annular guide cylinder, a first radially outward convex ring provided on the outer wall of the guide cylinder, and a radially inward convex ring provided on the inner wall of one end of the guide cylinder near the valve assembly, wherein the inner bore of the radially inward convex ring constitutes the first damping hole. The three-stage valve spool comprises an annular ejector rod, a second radially outward convex ring provided on the outer wall of the ejector rod, and a plurality of second radially through holes provided on the side wall of one end of the ejector rod near the two-stage spool. One end of the ejector rod is inserted into the guide cylinder and is restricted by the radially inward convex ring of the guide cylinder. The outer diameter of the ejector rod fits into the inner diameter of the guide cylinder and can relatively slidably close the plurality of second radially through holes. A bearing and a ball shoe are fitted to the other end of the ejector rod in the radial direction from the inside to the outside, and the end is provided to abut against the armature. The second radially outward convex ring is provided with a plurality of first axial through holes uniformly arranged around the circumference in the axial direction, The inner wall of the first axial blind hole is provided with a first annular groove and a second annular groove that fit onto the outer circumference of the first radially outward convex ring and the second radially outward convex ring, respectively. The side wall of the second annular groove is provided with a plurality of third radial through holes uniformly arranged circumferentially in the radial direction. A first pilot cavity is formed between the inner wall of the valve body, the first-stage spool assembly, and the second-stage spool, and the main spring is disposed within the first pilot cavity. A second pilot cavity 20 is formed in the cavity between the inner wall of the guide cylinder and the inner wall of the ejector rod, and between the armature, the outer wall of the ejector rod, the pole shoe, the bearing, and the inner wall of the first axial blind hole. An annular third pilot cavity is formed between the two-stage spool, the three-stage spool, and the inner wall of the first axial blind hole, and the small spring is placed inside the third pilot cavity. The first pilot cavity communicates with the outside through the flow path of the single-stage spool assembly, the first pilot cavity communicates with the second pilot cavity through the second damping hole, the second pilot cavity communicates with the third pilot cavity through the second radial through hole, the third pilot cavity communicates with the outside in order through the plurality of first axial through holes, the second annular groove, the plurality of third radial through holes, and the flow path gap, or communicates with the outside in order through the gap between the second radially outward convex ring and the inner wall of the first axial blind hole, the second annular groove, the plurality of third radial through holes, and the flow path gap. A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve, characterized in that the minimum value of the radial cross-sectional area of ​​the flow path of the single-stage spool assembly is smaller than the radial cross-sectional area of ​​the first damping hole, and the radial cross-sectional area of ​​the first damping hole is smaller than the sum of the radial cross-sectional areas of the multiple third radial through-holes.

[0010] Furthermore, the single-stage spool assembly comprises a valve seat, a single-stage spool, and a leaf spring, arranged in order from the outside to the inside along the axial direction within the valve body. The main spring is positioned between the leaf spring and the single-stage spool. The valve seat and the single-stage spool are each provided with a valve seat through-hole and a second damping hole that communicate with each other in sequence. The radial cross-sectional area of ​​the valve seat through-hole is larger than the radial cross-sectional area of ​​the second damping hole, and the radial cross-sectional area of ​​the second damping hole is smaller than the radial cross-sectional area of ​​the first damping hole. The first pilot cavity is in sequential communication with the outside through the second damping hole and the valve seat through hole.

[0011] Furthermore, the leaf spring and the main spring are integrated into a single structure.

[0012] Furthermore, an axially concave ring is provided at one end of the second radially outward convex ring closest to the two-stage spool, and the bottom surface of the axially concave ring is provided with the plurality of first axial through holes.

[0013] Furthermore, at one end of the inner wall of the yoke closest to the valve assembly, at least one annular groove and one annular boss are provided in sequence in the axial direction. The position of the annular groove corresponds to the position of the second annular groove, and at least one notch is provided on the inner circumference of the annular boss, and all of the annular grooves and all of the notches constitute the flow channel gap.

[0014] Furthermore, there are multiple annular grooves, and the diameter of the multiple annular grooves gradually increases along the axial direction and in the direction toward the valve body assembly.

[0015] Furthermore, the coil assembly further includes a circlip, and comprises a coil mold plug positioned at the other end of the yoke, and a coil body positioned between the inner wall of the yoke and the outer wall of the stop iron, The circlip is positioned between the coil body and the inner wall of the yoke.

[0016] Furthermore, a third annular groove is provided on the inner wall of the yoke, and an annular cavity is formed between the inner wall of the third annular groove and the outer wall of the stop iron. The coil body is disposed in the annular cavity, and the coil body includes a coil skeleton, enameled wire, a plastic-coated coil, and a magnetic path plate. A circlip is disposed between the plastic-coated coil and the inner wall of the third annular groove.

[0017] Furthermore, a composite coating is provided at a position corresponding to the armature on the inner wall of the first axial blind hole.

[0018] Furthermore, at least one second axial through hole 341 is provided in the axial direction on the armature 34, or a gap is provided between the armature 34 and the inner wall of the first axial blind hole.

Advantages of the Invention

[0019] The present invention has the following beneficial effects as compared with the prior art. (1) The three-stage pilot proportional pressure reducing solenoid valve of the present invention adopts a spool-type pilot valve structure, and integrates the second radially outer convex ring and the ejector rod into one part (three-stage spool). When the three-stage spool moves, both ends are supported by the bearings in the stop iron and the inner hole of the guide cylinder, forming a stable double support structure. However, in the plate-type relief valve structure adopted by the male ring type three-stage pilot proportional pressure reducing solenoid valve, the three-stage spool lacks an axial guiding and limiting structure. During the movement process, due to the liquid flow impact, the three-stage spool becomes eccentric, and due to the friction with the valve body, there are problems with the stability of the product. The present invention prevents the problem of contact friction caused by eccentricity between the three-stage spool and the valve body. (2) The three-stage pilot proportional pressure reducing solenoid valve of the present invention adopts a symmetric main valve flow path design and a double support two-stage pilot valve structure, and has excellent pressure stability. (3) The three-stage pilot inversely proportional pressure reducing solenoid valve of the present invention has four fewer parts compared to the male-ring type three-stage pilot inversely proportional pressure reducing solenoid valve (one bearing, one magnetic cut-off ring, one ejector rod, and one leaf spring are reduced). Since it adopts an integrated stop iron proportional electromagnet structure based on particle flow, the parts are processed and formed once, eliminating the need for secondary processing of the parts. In the production process of the present invention, the laser welding process is reduced by two times and the post-welding processing process is reduced by one time. Therefore, the production efficiency is high, the cost is low, and the quality is stable.

Brief Description of the Drawings

[0020] [Figure 1] It is a front view of an embodiment of the present invention. [Figure 2] It is a bottom view of an embodiment of the present invention. [Figure 3] It is a cross-sectional view taken along the A-A direction of FIG. 1. [Figure 4] It is a schematic cross-sectional structure diagram of a valve body assembly in an embodiment of the present invention. [Figure 5] It is a schematic structural diagram of a stop iron assembly in an embodiment of the present invention. [Figure 6] It is a schematic configuration diagram of a three-stage spool in an embodiment of the present invention. [Figure 7] It is a schematic cross-sectional structure diagram of an armature in an embodiment of the present invention. [Figure 8] It is a schematic cross-sectional structure diagram of a stop iron in an embodiment of the present invention. [Figure 9] It is a schematic cross-sectional structure diagram of a yoke in an embodiment of the present invention. [Figure 10] It is a schematic cross-sectional structure diagram of a coil body in an embodiment of the present invention. [Figure 11] It is a schematic configuration diagram of a coil skeleton in an embodiment of the present invention. [Figure 12] It is a schematic configuration diagram of an enameled wire in an embodiment of the present invention. [Figure 13] It is a schematic configuration diagram of a magnetic path plate in an embodiment of the present invention. [Figure 14]This is a schematic diagram of the structure of a plastic-coated coil in an embodiment of the present invention. [Figure 15] This is a schematic diagram 1 showing the operating principles of the first pilot cavity, the second pilot cavity, and the third pilot cavity in an embodiment of the present invention. [Figure 16] This is a schematic diagram 2 showing the operating principles of the first pilot cavity, the second pilot cavity, and the third pilot cavity in an embodiment of the present invention. [Modes for carrying out the invention]

[0021] The present invention will be further described below with reference to the drawings and embodiments.

[0022] Referring to Figures 1 to 14, the three-stage pilot-controlled inverse proportional pressure reducing solenoid valve comprises a yoke 1, a valve body assembly 2, a stop iron assembly 3, a coil assembly 4, and a circlip 5.

[0023] Referring to Figures 1 to 3, the yoke 1 is annular, a valve body assembly 2 is provided at one end of the yoke 1, and the coil assembly 4 is provided at the other end, a first cavity is formed between the valve body assembly 2, the yoke 1, and the coil assembly 4, and a stop iron assembly 3 is provided inside the first cavity.

[0024] Referring to Figure 4, the valve assembly 2 comprises an annular valve body 21, a valve seat 23 arranged axially from the outside to the inside within the valve body 21, a single-stage spool 24, a main spring 22, and a leaf spring 25. The valve seat 23, the single-stage spool 24, and the leaf spring 25 constitute a single-stage spool assembly. The valve body 21 is provided with a plurality of first radial through holes 211 uniformly arranged radially around the circumference. The valve seat 23 and the single-stage spool 24 are provided with a valve seat through hole (231) and a second damping hole (241) that communicate sequentially with each other.

[0025] Preferably, the leaf spring 25 and the main spring 22 are integrated, and a variable stiffness spring is used to achieve the same function, thereby reducing the number of parts and lowering costs.

[0026] Referring to Figure 5, the stop iron assembly 3 includes a stop iron 31, a two-stage spool 32, a three-stage spool 33, an armature 34, a small spring 35, a pole shoe 36, a bearing 37, and a composite coating 38.

[0027] The stop iron 31 is located within the first cavity, and a flow path gap is provided between the outer wall of one end of the stop iron 31 closest to the valve body 21 and the inner wall of the first cavity. The stop iron 31 is provided with a first axial blind hole that opens axially toward the valve body 21, and the two-stage spool 32, the three-stage spool 33, and the armature 34 are arranged sequentially in the axial direction within the first axial blind hole.

[0028] Referring to Figure 5, the two-stage spool 32 comprises an annular guide cylinder 321, a first radially outward convex ring 322 provided on the outer wall of the guide cylinder 321, and a radially inward convex ring 323 provided on the inner wall of one end of the guide cylinder 321 closest to the valve body assembly 2, with the inner bore of the radially inward convex ring 323 constituting the first damping hole 324.

[0029] The radial cross-sectional area of ​​the first damping hole 324 is larger than the radial cross-sectional area of ​​the second damping hole 241.

[0030] Referring to Figures 5 and 6, the three-stage spool 33 comprises an annular ejector rod 331, a second radially outward convex ring 332 provided on the side wall of one end of the ejector rod 331 near the two-stage spool 32, and a plurality of second radially through holes 333 provided on the side wall of the ejector rod 331. One end of the ejector rod 331 is inserted into the opening at one end of the guide cylinder 321 and is restricted by the radially inward convex ring 323 of the guide cylinder 321. The outer diameter of the ejector rod 331 fits into the inner diameter of the guide cylinder 321, allowing for relative sliding and the ability to close the plurality of second radially through holes 333. A bearing 37 and a pole shoe 36 are fitted to the other end of the ejector rod 331 in the radial direction from the inside to the outside, and the end is provided to abut against the armature 34. The second radially outward convex ring 332 is provided on the outer wall of the ejector pin 331. An axially concave ring 334 is provided at one end of the second radially outward convex ring 332 that is close to the two-stage spool 32, and a plurality of first axially through holes 335 are provided on the bottom surface of the axially concave ring 334, which are uniformly arranged around the circumference in the axial direction.

[0031] Referring to Figure 5, a composite coating 38 is provided on the inner wall of the first axial blind hole at a position corresponding to the armature 34. Referring to Figure 7, the armature 34 is provided with two second axial through holes 341 arranged symmetrically in the axial direction.

[0032] Referring to Figure 8, the inner wall of the first axial blind hole is provided with a first annular groove 311 and a second annular groove 312 that fit onto the outer circumferences of the first radially outward convex ring 322 and the second radially outward convex ring 332, respectively. The first annular groove 311 is for restricting the first radially outward convex ring 322 in the axial direction, and the side wall of the second annular groove 312 is provided with a plurality of third radial through holes 3121 uniformly arranged around the circumference in the radial direction, and the radial cross-sectional area of ​​the first damping hole 324 is smaller than the sum of the radial cross-sectional areas of the plurality of third radial through holes 3121.

[0033] Referring to Figure 9, the inner wall of the yoke 1 is provided with a third annular groove 11, and three annular grooves 12 and one annular boss 13 arranged sequentially in the axial direction and in the direction closer to the valve body assembly 2. An annular cavity is formed between the inner wall of the third annular groove 11 and the outer wall of the stop iron 31. The diameters of the three annular grooves 12 gradually increase in the axial direction and in the direction closer to the valve body assembly 2, corresponding to the position of the second annular groove 312. The inner circumference of the annular boss 13 is provided with two notches 14 uniformly arranged around the circumference.

[0034] Referring to Figures 3 and 10-14, the coil assembly 4 comprises a coil mold plug 41 located at the other end of the yoke 1 and a coil body 42 located in an annular cavity. The coil body 42 comprises a coil skeleton 421, enameled wire 422, a plastic-coated coil 423, and a magnetic path plate 424.

[0035] Referring to Figures 3, 5, 8, 15, and 16, a first pilot cavity 10 is formed between the inner wall of the valve body 21 and the first-stage spool 24 and the second-stage spool 32, and the main spring 22 is located inside the first pilot cavity 10. A second pilot cavity 20 is formed in the cavity between the inner wall of the guide cylinder 321, the inner wall of the ejector rod 331, the armature 34, the outer wall of the ejector rod 331, the pole shoe 36, the bearing 37, and the inner wall of the first axial blind hole. An annular third pilot cavity 30 is formed between the second-stage spool 32, the triple-stage spool 33, and the inner wall of the first axial blind hole, and the small spring 35 is located inside the third pilot cavity 30. The first pilot cavity 10 communicates with the outside via the second damping hole 241 and the valve seat through hole 231 in that order. The first pilot cavity 10 and the second pilot cavity 20 communicate via the first damping hole 324, and the second pilot cavity 20 and the third pilot cavity 30 communicate via the second radial through hole 333. The third pilot cavity 30 communicates with the outside via a plurality of first axial through holes 335, a second annular groove 312, a plurality of third radial through holes 3121, and a flow path gap in that order. Alternatively, it communicates with the outside via the gap between the second radial outward convex ring 332 and the inner wall of the first axial blind hole, the second annular groove 312, a plurality of third radial through holes 3121, and a flow path gap in that order.

[0036] Referring to Figures 3 and 9, the circlip 5 is positioned between the plastic-coated coil 423 and the inner wall of the third annular groove 11.

[0037] The operating principle of this invention is as follows:

[0038] 1. When the present invention is not energized. The single-stage spool 24 is subjected to the hydraulic biasing force of the P port, the elastic force of the main spring 22, and the elastic force of the leaf spring 25. When the pressure in the P port is small, the main spring 22 is compressed slightly, and the elastic force of the leaf spring 25 acts mainly, pressing the end face of the single-stage spool 24 against the valve seat 23, so there is no gap between the single-stage spool 24 and the valve seat 23, and the liquid cannot flow directly from the P port to the A port. Because the radial cross-sectional area of ​​the first damping hole 324 is larger than the radial cross-sectional area of ​​the second damping hole 241, the pressure in the second pilot cavity 20 is smaller than the pressure in the first pilot cavity 10. Because the radial cross-sectional area of ​​the first damping hole 324 is smaller than the sum of the radial cross-sectional areas of the multiple third radial through holes 3121, the pressure in the third pilot cavity 30 is smaller than the pressure in the second pilot cavity 20. At this time, the liquid flows into the first pilot cavity 10 from the outside through the valve seat through-hole 231 (P-hole) and the second damping hole 241 in sequence, then flows into the second pilot cavity 20 through the first damping hole 324, and then flows into the third pilot cavity 30 through a plurality of second radial through-holes 333. Finally, it flows out through the gap between the second radially outward convex ring 332 and the inner wall of the first axial blind hole, the second annular groove 312, a plurality of third radial through-holes 3121, three annular grooves 12, and two notches 14 (T-holes) (arrows in Figure 15). As the pressure in port P continues to increase, the pressure in port P becomes greater than the resultant force of the elastic forces between the leaf spring 25 and the main spring 22, causing the first-stage spool 24 to separate from the valve seat 23 by hydraulic pressure, forming a flow path between the first-stage spool 24 and the valve seat 23, and allowing the liquid to flow directly from port P to port A.

[0039] 2. When the present invention is energized. The armature 34 receives an electromagnetic force acting on the three-stage spool 33, which is acted upon by the pressure of the third pilot cavity 30 and the pressure of the second pilot cavity 20. When the electromagnetic force becomes greater than the combined force of the pressures of the third pilot cavity 30 and the second pilot cavity 20, the three-stage spool 33 moves toward the single-stage spool 24, and the liquid flows through the inner bore of the ejectoron 331, the second radial through-hole 333, into the second annular groove 312 of the stop iron 31, rapidly increasing the flow area, the pressure of the third pilot cavity 30 rapidly decreases, then the pressure of the second pilot cavity 20 and the pressure of the first pilot cavity 10 rapidly decreases, the single-stage spool 24 is acted upon by the pressure of the P port and rapidly opens to a large degree, and the pressure of the A port rapidly increases. As the current passing through the present invention increases and the electromagnetic force continues to increase, the three-stage spool 33 moves in the direction of the two-stage spool 32, and the flow path formed by the second radial through hole 333 of the three-stage spool 33 and the inner hole of the guide cylinder 321 continues to shrink. As a result, the pressure in the second pilot cavity 20 increases, followed by an increase in the pressure in the first pilot cavity 10. The three-stage spool 33 moves in the direction of the valve seat 23 due to the pressure in the first pilot cavity 10, the spring force of the main spring 22 and the leaf spring 25, and the pressure at the P port. As a result, the opening between the single-stage spool 24 and the valve seat 23 decreases, and the pressure at the A port continues to decrease. As the electromagnetic force continues to increase, the guide cylinder 321 closes the multiple second radial through holes 333, blocking the flow path formed by the multiple second radial through holes 333 of the three-stage spool 33 and the inner hole of the guide cylinder 321. The three-stage spool 33 moves towards the single-stage spool 24 until the pressure in the second pilot cavity 20 reaches its maximum. Then the pressure in the first pilot cavity 10 reaches its maximum, and the single-stage spool 24 is pressed against the valve seat 23 by the pressure in the first pilot cavity 10, the spring force, and the pressure in the P port, and the A port pressure reaches its minimum. At this time, referring to the arrows in Figure 16, the first axial through hole 335, the second annular groove 312, the multiple third radial through holes 3121, the three annular grooves 12, and the two notches 14 (T-shaped openings) communicate in sequence, and liquid flows out from the third pilot cavity 30 to the outside. [Explanation of Symbols]

[0040] 1... York, 11…Third annular groove, 12… Ring groove, 13... Loop Boss, 14... Notch, 2… Valve body assembly, 21... Valve body, 211...First radial through hole, 22... Main spring, 23...valve seat, 231... Valve seat through hole, 24... Single spool, 241...Second damping hole, 25... Leaf spring, 3… Stop iron assembly, 31…Stop iron assembly, 311...First ring groove, 312...Second ring groove, 3121...Third radial through hole, 32...Two-stage spool, 321... Guide tube, 322...First radially outward convex ring, 323... Radial inward convex ring, 324...First damping hole, 33... Three-stage spool, 331... Ejector rod, 332...Second radially outward convex ring, 333...Second radial through hole, 334...Axial concave ring, 335...First radial through hole, 34...Armacha, 341...Second axial through hole, 35... small spring, 36... Paul Shoe, 37... Bearings, 38…Composite coating, 4…Coil assembly, 41... Coil molded plug, 42... Coil body, 421... Coil skeleton, 422... Enamel wire, 423...Plastic coated coil, 424...magnetic path board, 5... Circlip, 10…First pilot cavity, 20…Second pilot cavity, 30…Third pilot cavity

Claims

1. A three-stage pilot-operated inverse proportional pressure reducing solenoid valve comprising a yoke (1) and a stop iron assembly (3), The yoke (1) is annular, and a valve body assembly (2) and a coil assembly (4) are provided at both ends of the yoke (1), and a first cavity is formed between the valve body assembly (2), the yoke (1), and the coil assembly (4). The valve body assembly (2) comprises an annular valve body (21), a single-stage spool assembly, and a main spring (22), and the valve body (21) is provided with a plurality of first radial through holes (211) uniformly arranged circumferentially in the radial direction. The stop iron assembly (3) comprises a stop iron (31) and a small spring (35). The stop iron (31) is located within the first cavity, and a flow path gap is provided between the outer wall of one end of the stop iron (31) near the valve body (21) and the inner wall of the first cavity, and the stop iron (31) is provided with a first axial blind hole that opens axially toward the valve body (21), and a two-stage spool (32), a three-stage spool (33), and an armature (34) are arranged in order from the outside to the inside in the axial direction within the first axial blind hole. The two-stage spool (32) comprises the annular guide cylinder (321), a first radially outward convex ring (322) provided on the outer wall of the guide cylinder (321), and a radially inward convex ring (323) provided on the inner wall of one end of the guide cylinder (321) near the valve body assembly (2), wherein the inner bore of the radially inward convex ring (323) constitutes a first damping hole (324). The three-stage spool (33) comprises an annular ejector rod (331), a second radially outward convex ring (332) provided on the outer wall of the ejector rod (331), and a plurality of second radially through holes (333) provided on the side wall of one end of the ejector rod (331) near the two-stage spool (32), with one end of the ejector rod (331) inserted into the guide cylinder (321), and the guide cylinder (321) The outer diameter of the ejector rod (331) is limited by a radially inward convex ring (323), and the outer diameter of the ejector rod (331) fits into the inner diameter of the guide cylinder (321), and the plurality of second radial through holes (333) can be slidably closed relative to each other. A bearing (37) and a pole shoe (36) are fitted to the other end of the ejector rod (331) in the radial direction from the inside to the outside, and the end is provided to abut against the armature (34). The second radially outward convex ring (332) is provided with a plurality of first axial through holes (335) uniformly arranged around the circumference in the axial direction. The inner wall of the first axial blind hole is provided with a first annular groove (311) and a second annular groove (312) that fit onto the outer circumference of the first radially outward convex ring (322) and the second radially outward convex ring (332), respectively. The side wall of the second annular groove (312) is provided with a plurality of third radial through holes (3121) uniformly arranged circumferentially in the radial direction. A first pilot cavity (10) is formed between the inner wall of the valve body (21), the first-stage spool assembly, and the second-stage spool (32), and the main spring (22) is disposed within the first pilot cavity (10). A second pilot cavity (20) is formed in the cavity between the inner wall of the guide cylinder (321) and the inner wall of the ejector rod (331), and between the armature (34), the outer wall of the ejector rod (331), the pole shoe (36), the bearing (37), and the inner wall of the first axial blind hole. An annular third pilot cavity (30) is formed between the two-stage spool (32), the three-stage spool (33), and the inner wall of the first axial blind hole, and the small spring (35) is placed inside the third pilot cavity (30). The first pilot cavity (10) communicates with the outside through the flow path of the single-stage spool assembly, the first pilot cavity (10) communicates with the second pilot cavity (20) and the first damping hole (324), the second pilot cavity (20) and the third pilot cavity (30) communicate with each other through the second radial through hole (333), the third pilot cavity (30) communicates with the outside in order through the plurality of first axial through holes (335), the second annular groove (312), the plurality of third radial through holes (3121), and the flow path gap, or communicates with the outside in order through the gap between the second radial outward convex ring (332) and the inner wall of the first axial blind hole, the second annular groove (312), the plurality of third radial through holes (3121), and the flow path gap. The minimum value of the radial cross-sectional area of ​​the flow path of the single-stage spool assembly is smaller than the radial cross-sectional area of ​​the first damping hole (324), and the radial cross-sectional area of ​​the first damping hole (324) is smaller than the sum of the radial cross-sectional areas of the multiple third radial through holes (3121). A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve characterized by the above.

2. The aforementioned single-stage spool assembly comprises a valve seat (23) arranged in order from the outside to the inside along the axial direction within the valve body (21), a single-stage spool (24), and a leaf spring (25). The main spring (22) is positioned between the leaf spring (25) and the single-stage spool (24). The valve seat (23) and the single-stage spool (24) are provided with a valve seat through-hole (231) and a second damping hole (241) that communicate with each other in sequence. The radial cross-sectional area of ​​the valve seat through-hole (231) is larger than the radial cross-sectional area of ​​the second damping hole (241), and the radial cross-sectional area of ​​the second damping hole (241) is smaller than the radial cross-sectional area of ​​the first damping hole (324). The first pilot cavity (10) communicates with the outside in order through the second damping hole (241) and the valve seat through hole (231). A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve according to claim 1, characterized in that it is a three-stage pilot-operated inverse-proportional pressure reducing solenoid valve.

3. The leaf spring (25) and the main spring (22) are integrally structured. A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve according to claim 2, characterized in that it is a three-stage pilot-operated inverse-proportional pressure reducing solenoid valve.

4. An axially concave ring (334) is provided at one end of the second radially outward convex ring (332) closest to the two-stage spool (32), and the bottom surface of the axially concave ring (334) is provided with the plurality of first axial through holes (335). A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve according to claim 1, characterized in that it is a three-stage pilot-operated inverse-proportional pressure reducing solenoid valve.

5. At one end of the inner wall of the yoke (1) closest to the valve assembly (2), at least one annular groove (12) and one annular boss (13) are provided in order in the axial direction. The position of the annular groove (12) corresponds to the position of the second annular groove (312), and at least one notch (14) is provided on the inner circumference of the annular boss (13), and all of the annular grooves (12) and all of the notches (14) constitute the flow channel gap. A three-stage pilot-operated inverse-proportional pressure reducing solenoid valve according to claim 1, characterized in that it is a three-stage pilot-operated inverse-proportional pressure reducing solenoid valve.

6. The annular grooves (12) are numerous, and the diameter of the multiple annular grooves (12) gradually increases in the axial direction and in the direction approaching the valve body assembly (2). A three-stage pilot inverse proportional pressure reducing solenoid valve according to claim 5, characterized in that

7. The coil assembly (4) further includes a circlip (5), and comprises a coil mold plug (41) positioned at the other end of the yoke (1), and a coil body (42) positioned between the inner wall of the yoke (1) and the outer wall of the stop iron (31), The circlip (5) is positioned between the coil body (42) and the inner wall of the yoke (1). A three-stage pilot inverse proportional pressure reducing solenoid valve according to any one of claims 1 to 6, characterized in that

8. A third annular groove (11) is provided in the inner wall of the yoke (1), and an annular cavity is formed between the inner wall of the third annular groove (11) and the outer wall of the stop iron (31). The coil body (42) is disposed within the annular cavity, and the coil body (42) comprises a coil skeleton (421), enameled wire (422), plastic-coated coil (423), and magnetic path plate (424). A circlip (5) is positioned between the plastic-coated coil (423) and the inner wall of the third annular groove (11). A three-stage pilot inverse proportional pressure reducing solenoid valve according to claim 7, characterized in that

9. A composite coating (38) is provided at a position corresponding to the armature (34) on the inner wall of the first axial blind hole. A three-stage pilot inverse proportional pressure reducing solenoid valve according to claim 8, characterized in that

10. The armature (34) is provided with at least one second axial through hole (341) in the axial direction, or a gap is provided between the armature (34) and the inner wall of the first axial blind hole. A three-stage pilot inverse proportional pressure reducing solenoid valve according to claim 9, characterized in that

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