An electromagnetic valve

Abstract

The present application provides an electromagnetic valve, comprising an electromagnetic drive assembly, an overflow valve assembly and a spherical seal, the end of the push rod device is fixed with the spherical seal through a retaining structure. The spherical seal has a spherical outer surface, which forms a line contact seal with the center hole of the valve plate assembly and the end hole rim of the pilot valve cavity. The self-centering ability of the ball automatically compensates for assembly deviations and eliminates local gap leakage. The high sealing specific pressure and uniform stress characteristics of the spherical seal improve the high-pressure deformation resistance. Through the comprehensive improvement of the leakage of the spherical seal at three key sealing points, the low-pressure performance of the electromagnetic valve remains stable, the high-pressure leakage is effectively suppressed, the upper limit of the pressure is greatly improved, the pressure regulation range is significantly widened, and the sealing reliability and durability are enhanced.

Description

Technical Field

[0001] This invention relates to the field of vibration damping devices, and more particularly to a solenoid valve. Background Technology

[0002] As a core actuator in fluid control systems, the solenoid valve directly affects the system's control accuracy and operational reliability by controlling flow path opening and closing and regulating pressure. In pilot-operated solenoid valves, the sealing performance between the push rod and the valve seat mating surface is a key factor determining the valve's internal leakage level and pressure regulation capability. Existing sealing structures, during operation, are susceptible to damage from machining errors and assembly deviations, making it difficult to achieve a uniform and reliable seal. This can easily lead to localized gaps and minute leaks in high-pressure media. As system pressure increases, the uneven stress on the sealing surface intensifies, further increasing leakage and significantly limiting the valve's pressure ceiling, making it difficult to maintain stable sealing and control performance over a wide pressure range. Summary of the Invention

[0003] This invention provides a solenoid valve to solve the technical problems of sealing leakage and limited pressure range caused by assembly deviation and high-pressure deformation of solenoid valve seals.

[0004] The solenoid valve provided by this invention includes: An electromagnetic drive assembly, the electromagnetic drive assembly including a push rod device movable in an axial direction; An overflow valve assembly is connected to one end of the electromagnetic drive assembly. The overflow valve assembly includes a main valve assembly, a pilot valve assembly, and a valve plate assembly, and forms a main valve chamber, a pilot valve chamber, and a pressure relief chamber. The main valve chamber is connected to the pilot valve chamber, and the pilot valve chamber is separated from the pressure relief chamber by the valve plate assembly. The valve plate assembly has a central hole, and the push rod device passes through the central hole and extends to one side of the pilot valve chamber. A spherical seal is disposed at the end of the push rod device. The push rod device fixes the spherical seal by a retaining structure formed at its end, or the spherical seal is welded to the end of the push rod device. The spherical seal is configured to move between a first position and a second position under the action of the push rod device. When the spherical seal is in the first position, it seals the central hole to cut off the communication between the pilot valve chamber and the pressure relief chamber. When the spherical seal is in the second position, it seals one end of the pilot valve chamber to cut off the communication between the pilot valve chamber and the pressure relief chamber.

[0005] In one embodiment of the present invention, the main valve assembly includes: The valve body has one end connected to the electromagnetic drive assembly and the other end provided with a liquid inlet. The valve body has a valve hole on its side. A valve core is axially movable within the valve body to connect or disconnect the first pressure relief channel formed when the inlet is connected to the valve hole. The main valve chamber is formed within the valve core and is connected to the inlet.

[0006] In one embodiment of the present invention, the pilot valve assembly is disposed in the main valve chamber, and the pilot valve chamber is formed by the hollow interior of the pilot valve assembly. The pilot valve chamber and the main valve chamber are kept in communication through a throttling orifice. The spherical seal is configured to be axially displaced under the action of the push rod device to connect or disconnect the second pressure relief channel formed when the pilot valve chamber is connected to the pressure relief chamber, or to continuously adjust the flow area of ​​the second pressure relief channel.

[0007] In one embodiment of the present invention, the valve plate assembly includes: A valve plate body is disposed between the pilot valve assembly and the electromagnetic drive assembly. The side of the valve plate body opposite to the pilot valve assembly forms the pressure relief chamber. The valve plate body is provided with a flow hole that extends axially and is used to connect the pilot valve chamber and the pressure relief chamber. An elastic element is disposed on the side of the valve plate away from the spherical seal. The elastic element covers the flow hole by applying a pre-tightening force to the valve plate, and is used to connect or disconnect the pilot valve cavity and the third pressure relief channel formed when the flow hole and the pressure relief cavity are connected.

[0008] In one embodiment of the present invention, the spherical seal has a spherical outer surface, and the spherical outer surface forms a line contact seal with the central hole and the edge of the pilot valve cavity.

[0009] In one embodiment of the present invention, the retaining structure includes a flanged structure that wraps around a portion of the spherical seal.

[0010] In one embodiment of the present invention, the diameter of the spherical seal is larger than the diameter of the central hole, and the ratio of the diameter of the spherical seal to the diameter of the central hole is configured to a preset value.

[0011] In one embodiment of the present invention, the electromagnetic drive assembly further includes a housing and a coil, and the push rod device includes: An armature is disposed within the housing; A shaft is connected to the housing via the armature. An armature spring is provided axially between the armature and the housing. The armature spring applies a preload force to the shaft, which tends to press the spherical seal against the central hole. When the coil is energized, it drives the shaft to move the spherical seal between the first position and the second position. When the power is off, the shaft and the spherical seal at its end move to the first position under the action of the armature spring and seal the center hole.

[0012] In one embodiment of the present invention, the end of the shaft is provided with a shoulder step, and the spherical seal is axially pressed against the end face of the shoulder step under the buckling pressure of the flange structure, or the spherical seal is axially fixed to the end face of the shoulder step by welding.

[0013] In one embodiment of the present invention, the pilot valve cavity and / or the end of the central hole that mates with the spherical seal is provided with an annular groove or a chamfer.

[0014] The beneficial effects of this invention are as follows: The solenoid valve proposed in this invention achieves an adaptive line contact seal between the spherical surface and the bore edge by using a seal with a spherical outer surface and fixing the structure at the end of the push rod device. This effectively eliminates local gaps caused by assembly deviations. At the same time, the line contact seal pressure is significantly improved, and the spherical surface rotates symmetrically with uniform force, resulting in strong resistance to deformation under high pressure and extending the life of the sealing components. By switching between dual-position sealing between the spherical seal and the end of the pilot valve cavity, the leakage between the seal and the valve plate and between the seal and the pilot valve seat is reduced, ensuring that the failure protection pressure does not decrease when not energized and the valve opening pressure is not lost when energized. The spherical seal is pressed and fixed by the shaft end flange structure, eliminating the leakage path between the seal and the shaft and avoiding a decrease in back pressure at the pilot valve. Through comprehensive improvement of the above three leakage points, the performance in the low-pressure section remains stable, leakage in the high-pressure section is effectively suppressed, the upper pressure limit is increased by about 100%, and the pressure range is significantly widened. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0016] In the attached diagram: Figure 1 This is a schematic diagram of the structure of a solenoid valve provided in an embodiment of the present invention; Figure 2 This is a partial structural schematic diagram of a solenoid valve provided in one embodiment of the present invention; Figure 3 This is a diagram showing the valve opening characteristics of a solenoid valve under a 0.3A current with an annular sealing structure provided in one embodiment of the present invention. Figure 4This is a diagram showing the valve opening characteristics of a solenoid valve under a current of 1.6A with an annular sealing structure provided in one embodiment of the present invention. Figure 5 This is a diagram showing the valve opening characteristics of a solenoid valve under a 0.3A current with a spherical sealing structure provided in one embodiment of the present invention. Figure 6 This is a curve showing the valve opening characteristics of a solenoid valve under a 1.6A current with a spherical sealing structure provided in one embodiment of the present invention.

[0017] The attached figures are labeled as follows: 100. Electromagnetic drive assembly; 200. Relief valve assembly; 300. Spherical seal; 110. Push rod device; 120. Housing; 130. Coil; 111. Armature; 112. Shaft; 113. Armature spring; 114. Stationary iron core; 210. Main valve assembly; 220. Pilot valve assembly; 230. Valve plate assembly; 240. Main valve chamber; 250. Pilot valve chamber; 260. Pressure relief chamber; 211. Valve body; 212. Valve core; 213. Liquid inlet; 231. Center hole; 232. Valve plate body; 233. Leaf spring; 234. Preload spring. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0019] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0020] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the invention. However, it will be apparent to those skilled in the art that embodiments of the invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the invention.

[0021] As a core actuator in fluid control systems, the solenoid valve directly affects the system's response speed, control accuracy, and operational reliability, enabling flow path on / off, pressure regulation, and directional control. In traditional pilot-operated relief solenoid valves, the connection and sealing structure between the electromagnetic drive section and the pilot valve section typically employs an annular planar sealing structure. This rigid surface contact results in extremely low tolerance for misalignment, requiring very high precision in the coaxiality machining of the push rod and valve seat bore. In actual production and assembly, errors in flatness, parallelism, and coaxiality are unavoidable in the valve core and valve seat. After assembly, the sealing surface is prone to localized misalignment and gaps. Under high pressure, the medium leaks through these micro-gaps, leading to increased internal leakage, decreased pressure control accuracy, and even valve failure. Furthermore, during frequent opening and closing, uneven stress distribution on the sealing surface causes warping and extrusion deformation at the edges, resulting in permanent plastic deformation and further exacerbating the leakage risk. Furthermore, planar seals rely entirely on assembly precision and cannot automatically compensate for coaxial deviations between the valve core and valve seat. This results in high manufacturing costs, poor consistency, and while the seal can be maintained at low pressures, leakage increases sharply as system pressure rises, failing to meet the requirements for stable operation across a wide pressure range.

[0022] Please see Figures 1 to 2This invention proposes a solenoid valve, comprising an electromagnetic drive assembly 100, a relief valve assembly 200, and a spherical seal 300. Through the coordinated operation of the electromagnetic drive assembly 100 and the relief valve assembly 200, and by using the spherical seal 300 as the core sealing element of the pilot control end, the inconsistency in sealing caused by part machining errors and assembly errors is fundamentally improved, achieving a comprehensive improvement in sealing reliability and pressure regulation range. The electromagnetic drive assembly 100 includes an axially movable push rod device 110. Driven by electromagnetic force, the push rod device 110 can perform precise displacement along its axial direction, thereby outputting mechanical thrust to control the valve state. The relief valve assembly 200 is connected to one end of the electromagnetic drive assembly 100. The relief valve assembly 200 internally integrates a main valve assembly 210, a pilot valve assembly 220, and a valve plate assembly 230, and forms chambers such as a main valve chamber 240, a pilot valve chamber 250, and a pressure relief chamber 260. The main valve chamber 240 and the pilot valve chamber 250 are in communication, allowing the medium pressure in the main valve chamber 240 to be transmitted to the pilot valve chamber 250. The pilot valve chamber 250 and the pressure relief chamber 260 are separated by a valve plate assembly 230, which has a central hole 231 that serves as a controlled flow channel connecting the pilot valve chamber 250 and the pressure relief chamber 260. The push rod device 110 passes through the central hole 231 and extends towards the pilot valve chamber 250, with its end extending into the region of the pilot valve chamber 250. A spherical seal 300 is disposed at the end of the push rod device 110, and the push rod device 110 securely fixes the spherical seal 300 thereto by a retaining structure formed at its end, or the spherical seal 300 is fixed to the end of the push rod device 110 by welding. The spherical seal 300 is configured to move between a first position and a second position under the action of the push rod device 110: when the spherical seal 300 is in the first position, it forms a sealing fit with the central hole 231 of the valve plate assembly 230, closing the central hole 231 and thereby cutting off the communication between the pilot valve chamber 250 and the pressure relief chamber 260; when the spherical seal 300 is between the first position and the second position, the central hole 231 is opened, and the main valve chamber 240, the pilot valve chamber 250 and the pressure relief chamber 260 are connected; when the spherical seal 300 is in the second position, it leaves the central hole 231 and moves further to form a sealing fit with one end of the pilot valve chamber 250, disconnecting the communication between the main valve chamber 240 and the pressure relief chamber 260.

[0023] Please see Figures 1 to 2This invention employs a combined structure of a spherical seal 300 and a push rod device 110, along with a dual-position sealing design at the center hole 231 of the valve plate assembly 230 and the end of the pilot valve cavity 250. The spherical seal 300 utilizes the line contact sealing formed between its spherical outer surface and the edge of the center hole 231 and the end edge of the pilot valve cavity 250. The spherical seal has a natural self-aligning capability, and the spherical surface has a degree of freedom of spatial rotation. Regardless of assembly deviations or slight misalignment or eccentricity of the push rod device 110's shaft 112 during movement, the spherical surface can automatically align itself, always forming a continuous closed annular sealing line with the hole edge, fundamentally eliminating local gap leakage caused by part machining errors and assembly deviations. At the same time, the sealing pressure of line contact is significantly improved compared to planar contact, resulting in stronger resistance to deformation under high pressure. The spherical surface has a rotationally symmetrical structure, ensuring uniform stress distribution under high-pressure oil, and preventing edge warping and stress concentration phenomena that occur with planar seals. It is less prone to plastic deformation and fatigue cracking, which can extend the life of core components and thus improve the durability of the solenoid valve. During the opening and closing process, the contact position of the spherical seal changes due to rolling or slight sliding, avoiding concentrated wear of the traditional sealing surface in a fixed area, and further extending the seal life. The retaining structure formed at the end of the push rod device 110 reliably fixes the spherical seal 300, preventing the ball from falling off under fluid impact or high-frequency action. At the same time, the retaining structure's wrapping or clamping effect on the ball further enhances the overall rigidity of the structure and the accuracy of motion transmission. By switching the spherical seal 300 between the first and second positions, the valve can realize the on / off control of the flow path between the main valve chamber 240, the pilot valve chamber 250 and the pressure relief chamber 260, providing a structural basis for the valve to realize complex pressure regulation logic, especially suitable for applications requiring pilot control or multi-stage pressure relief.

[0024] Please see Figures 1 to 2In an optional embodiment of the present invention, the overflow valve assembly 200 serves as the actuator for regulating medium pressure. It is assembled from the main valve assembly 210, the pilot valve assembly 220, and the valve plate assembly 230, defining multiple functional chambers such as the main valve chamber 240, the pilot valve chamber 250, and the pressure relief chamber 260. The system pressure is controlled and released through the switching of internal multi-stage pressure relief channels. Specifically, the main valve chamber 240 receives the high-pressure medium from the inlet 213; the pilot valve chamber 250 is located within the main valve chamber 240 and maintains pressure communication with it through a throttling orifice or connecting groove on one side, allowing the pressure of the main valve chamber 240 to be transmitted to the pilot valve chamber 250. Simultaneously, the damping effect of the throttling orifice prevents instantaneous impacts of pressure fluctuations on the pilot valve; the pressure relief chamber 260 is located on the side of the valve plate assembly 230 away from the pilot valve chamber 250 and is connected to the low-pressure side of the system or the oil tank through an oil drain port on the housing 120. The valve plate assembly 230 is installed between the pilot valve assembly 220 and the electromagnetic drive assembly 100, and its central hole 231 forms a controlled channel between the pilot valve chamber 250 and the pressure relief chamber 260. Driven by the push rod device 110, the spherical seal 300 can selectively seal the central hole 231 or one end of the pilot valve chamber 250. When the spherical seal 300 seals the central hole 231, the pilot valve chamber 250 and the pressure relief chamber 260 are isolated, and the pressure in the pilot valve chamber 250 remains balanced with the pressure in the main valve chamber 240. When the spherical seal 300 leaves the central hole 231, the medium in the pilot valve chamber 250 is released through the central hole 231 into the pressure relief chamber 260, and the pressure in the pilot valve chamber 250 drops rapidly, driving the opening action of the main valve assembly 210 through this pressure change. When the spherical seal 300 moves further to one end of the pilot valve chamber 250 and seals therewith, the direct communication path between the pressure relief chamber 260 and the main valve chamber 240 is blocked. The multi-chamber structure of the relief valve assembly 200 provides a carrier for the dual-position sealing function of the spherical seal 300, and the precise displacement control of the spherical seal 300 provides a reliable pilot control means for the pressure regulation of the relief valve assembly 200.

[0025] It should be noted that the use of the spherical seal 300 reduces leakage at three key sealing points, thereby fundamentally improving the leakage characteristics of the solenoid valve. Firstly, the spherical seal 300 reduces leakage between the seal and the pilot valve assembly 220, ensuring that the opening pressure of the pilot valve assembly 220 does not decrease due to leakage. Secondly, the spherical seal 300 reduces leakage between the seal and the valve plate assembly 230, preventing a drop in the failure protection pressure of the solenoid valve when it is not energized due to leakage at this point. Furthermore, this invention uses a retaining structure to press the spherical seal 300 onto the shaft 112, preventing a decrease in back pressure at the solenoid valve pilot valve due to leakage between the seal and the shaft 112, thus avoiding an overall pressure drop. Experiments have shown that leakage has a relatively small impact on low-pressure conditions, but a significant impact on high-pressure conditions. After using the spherical seal 300, the low-pressure range remains almost unchanged, while in the high-pressure range, after leakage is effectively suppressed, the upper pressure limit is significantly increased, thereby significantly widening the operating pressure range of the solenoid valve.

[0026] Please see Figures 1 to 2 In an optional embodiment of the present invention, the main valve assembly 210 includes a valve body 211 and a valve core 212. The valve body 211 is generally cylindrical, with one end fixedly connected to the housing 120 of the electromagnetic drive assembly 100 by means of threads or snap rings, and the other end provided with a liquid inlet 213 for connection to the high-pressure side pipeline of the system. At least one valve hole is provided on the side of the valve body 211, which serves as a pressure relief outlet and communicates with the low-pressure side of the system or the oil tank. The valve core 212 is axially movable inside the valve body 211, and the hollow interior of the valve core 212 forms a main valve chamber 240. The main valve chamber 240 communicates with the liquid inlet 213 through a central flow hole at the end of the valve core 212, allowing the high-pressure medium at the liquid inlet 213 to enter the interior of the main valve chamber 240. A precision sliding fit surface is provided between the outer circular surface of the valve core 212 and the inner hole of the valve body 211. The valve core 212 can move axially within the valve body 211 to connect or disconnect the first pressure relief channel, i.e., the main valve channel, formed when the inlet port 213 is connected to the valve hole. Specifically, the valve body 211 includes a valve shell and a valve seat fixed to the end of the valve shell. The mating end faces of the valve core 212 and the valve seat are respectively provided with a first groove structure and a second groove structure. The first groove structure and the second groove structure form a sealing fit surface for connecting or disconnecting the flow path between the inlet port 213 and the valve hole. When the valve core 212 is in the closed position, its end face is pressed against the valve seat, blocking the path of the medium from the inlet port 213 through the periphery of the valve core 212 to the valve hole, i.e., the first pressure relief channel. When the valve core 212 moves in the opening direction due to the pressure difference between the two ends, the first pressure relief channel is opened, and the medium can be discharged from the inlet port 213 through the periphery of the main valve cavity 240 and the valve hole to the low-pressure side, realizing the release of the main medium flow.

[0027] Please see Figures 1 to 2In an optional embodiment of the present invention, a pilot valve assembly 220 is disposed within a main valve chamber 240, and a pilot valve chamber 250 communicating with the main valve chamber 240 is formed therein. One side of the pilot valve chamber 250 is kept in communication with the main valve chamber 240 through a throttling orifice, and a transition chamber is formed between the other side of the pilot valve chamber 250 and the valve plate assembly 230. The pilot valve chamber 250 can communicate with the central hole 231 and the pressure relief chamber 260 on the valve plate assembly 230 through this chamber. When the pilot valve chamber 250 is in communication with the pressure relief chamber 260, a second pressure relief channel is formed, namely a pilot adjustment channel. The central hole 231 cooperates with the spherical seal 300 to form the controlled port of the second pressure relief channel. The spherical seal 300 is configured to be axially displaced under the action of the push rod device 110 to connect or disconnect the second pressure relief channel formed when the pilot valve chamber 250 is in communication with the pressure relief chamber 260, or to continuously adjust the flow area of ​​the second pressure relief channel. During valve operation, the opening and closing state of the second pressure relief channel is determined by the position of the spherical seal 300: when the spherical seal 300 is in the first position sealing the central hole 231, the second pressure relief channel is cut off; when the electromagnetic drive assembly 100 is energized, the spherical seal 300 leaves the central hole 231, the second pressure relief channel is opened, and the high-pressure medium in the pilot valve chamber 250 quickly flows into the pressure relief chamber 260 through the central hole 231 and is discharged to the low-pressure side. Due to the flow restriction effect of the throttling orifice, the pressure in the pilot valve chamber 250 drops rapidly, and the pressure in the main valve chamber 240 is significantly higher than the pressure in the pilot valve chamber 250. When the pressure difference on both sides of the valve core 212 overcomes the force of the reset spring, it moves in the opening direction, opening the first pressure relief channel and realizing the main pressure relief function.

[0028] Please see Figures 1 to 2In an optional embodiment of the present invention, the spherical seal 300 has a spherical outer surface, which forms a line contact seal with the central hole 231 and the edge of the pilot valve cavity 250, playing a key role in the pilot control stage. Due to the adaptive capability of the spherical seal 300 to a coaxial 112-degree deviation, even if the push rod device 110 experiences a slight deflection due to changes in the guide clearance during long-term operation, the spherical surface can still maintain a uniform annular line contact with the edge of the central hole 231, ensuring reliable sealing of the second pressure relief channel in the closed state and preventing pressure runaway caused by pilot leakage. At the same time, during the opening process, as the push rod device 110 moves, the annular gap between the spherical surface and the edge of the central hole 231 gradually increases, and the change in flow area has a good linear relationship with the push rod displacement. This characteristic makes the flow regulation of the second pressure relief channel highly controllable, providing ideal pilot regulation characteristics for achieving proportional pressure control. Furthermore, when the spherical seal 300 moves further to the second position and forms a seal with one end of the pilot valve chamber 250, the communication between the pressure relief chamber 260 and the main valve chamber 240 is blocked, the second pressure relief channel is closed, and a large flow of pressure is released through the main valve channel. The pressure of the pilot valve chamber 250 is connected to the main valve chamber 240 through the throttle orifice. The pressure state of the pilot valve chamber 250 remains stable, and the main valve core 212 opens smoothly.

[0029] Please see Figures 1 to 2 In an optional embodiment of the present invention, the valve plate assembly 230 is disposed at the end of the valve body 211 away from the liquid inlet 213, located between the electromagnetic drive assembly 100 and the pilot valve assembly 220, and the pressure relief chamber 260 is located on the side of the valve plate assembly 230 away from the pilot valve assembly 220. The valve plate assembly 230 includes a valve plate body 232 disposed between the pilot valve assembly 220 and the electromagnetic drive assembly 100 and an elastic element disposed on the side of the valve plate body 232 away from the spherical seal 300. A flow hole is provided circumferentially on the valve plate body 232 and extending axially to connect the pilot valve chamber 250 and the pressure relief chamber 260. The elastic element covers the flow hole by applying a pre-tightening force to the valve plate body 232, which is used to connect or cut off the third pressure relief channel formed when the pilot valve chamber 250, the flow hole and the pressure relief chamber 260 are connected, i.e., the failure protection channel. When the spherical seal 300 is in the first position or between the first and second positions, the flow hole communicates with the main valve chamber 240 through the pilot valve chamber 250. When the spherical seal 300 is in the second position and seals the end of the pilot valve chamber 250, the communication between the flow hole and the main valve chamber 240 is disconnected.

[0030] Please see Figures 1 to 2In an optional embodiment of the present invention, the elastic element includes a leaf spring 233 and a preload spring 234. The preload spring 234 is, for example, a wave spring, used to provide preload force to the leaf spring 233. The leaf spring 233 adopts a cantilever beam structure. A flow groove communicating with the flow hole is provided on the valve plate 232. Under the preload force of the preload spring 234, the leaf spring 233 is pressed against the end face of the flow groove of the valve plate, forming a valve port that can be opened by pressure, which can serve as a damping source in the fail-safe state. When the electromagnetic drive assembly 100 is not energized, the spherical seal 300 tightly closes the center hole 231 of the valve plate 232. The cooperation between the leaf spring 233 and the flow hole can dampen the flow of the medium, forming a fail-safe function. The third pressure relief channel opens when the pressure reaches the threshold, providing a stable, non-electrically controlled fixed damping channel to ensure the most basic safe operation damping of the system, greatly reducing energy consumption and accident risk.

[0031] Please see Figures 1 to 2 In an optional embodiment of the present invention, the overflow valve assembly 200, through the cooperation of the main valve assembly 210, the pilot valve assembly 220, the valve plate assembly 230, and a series of chambers, constructs multiple pressure relief channels with different opening pressure thresholds, realizing graded management of fluid pressure. The first pressure relief channel (i.e., the main valve channel) bears large-flow pressure relief and is directly controlled by the displacement of the valve core 212. The second pressure relief channel (i.e., the pilot adjustment channel) serves as a precision adjustment channel and is actively controlled by the electromagnetic drive assembly 100. The third pressure relief channel (i.e., the failure protection channel) serves as a medium-pressure relief and power failure protection channel and is controlled by the force balance between fluid pressure and elastic elements. The three work together to enable the solenoid valve to cope with various working conditions. The electromagnetic drive assembly 100 serves as the actuation power source, converting the input electrical energy into the axial mechanical displacement of the push rod device 110, controlling the opening and closing of the second pressure relief channel and the flow area. The spherical seal 300 serves as a key sealing and transmission element connecting the two, realizing highly reliable flow channel sealing and opening.

[0032] Please see Figures 1 to 2In an optional embodiment of the present invention, the electromagnetic drive assembly 100 includes a housing 120, a coil 130, and a push rod device 110 movable along the axial direction. The housing 120 is made of a magnetically conductive material and has an internal cavity for accommodating the coil 130 and the push rod device 110. One end of the housing 120 is fixedly connected to the valve body 211 of the overflow valve assembly 200. The coil 130 is wound on an insulating frame and fitted inside the housing 120. When current is applied to the coil 130, an axially distributed electromagnetic field is generated. The push rod device 110 mainly includes an armature 111 and a shaft 112. The armature 111 is also made of a soft magnetic material, located inside the housing 120, and is slidable along the axial direction. An armature spring 113 is axially arranged between the armature 111 and the housing 120. The armature spring 113 applies a preload force to the armature 111 and the shaft 112 connected thereto, tending to press the spherical seal 300 against the center hole 231 of the valve plate assembly 230. One end of the shaft 112 is connected to the armature 111 by a ring riveting process, and the other end extends axially through the center hole 231 of the valve plate assembly 230 of the overflow valve assembly 200. The shaft 112 is supported and connected to the housing 120 by sliding shaft bearings at both ends. The shaft bearings are pressed into the connecting holes on the housing 120 and the stationary iron core 114 with an interference fit. This double-point support ensures the axial straightness of the shaft 112 during reciprocating motion, preventing uneven wear and jamming. The end of the shaft 112 is fixed with a spherical seal 300 by a retaining structure.

[0033] Please see Figures 1 to 2 In an optional embodiment of the present invention, when the electromagnetic drive assembly 100 is not energized, the coil 130 does not generate electromagnetic force. Under the preload of the armature spring 113, the armature 111 and shaft 112 move toward the overflow valve assembly 200, pressing the spherical seal 300 against the central hole 231, and the valve is in a closed state. When the coil 130 is energized, the generated electromagnetic force overcomes the preload of the armature spring 113 and the pressure of the fluid acting on the spherical seal 300, attracting the armature 111 to drive the shaft 112 and the spherical seal 300 to move away from the central hole 231. The magnitude of the electromagnetic force is positively correlated with the current of the coil 130. By adjusting the magnitude of the current of the coil 130, the axial displacement of the armature 111 and shaft 112 can be precisely controlled, thereby precisely controlling the opening between the spherical seal 300 and the central hole 231. Proportional displacement control can be achieved by controlling the current of coil 130. The flow area between spherical seal 300 and center hole 231 changes with the current, thereby continuously adjusting the flow rate of the second pressure relief channel and realizing proportional adjustment of the pressure of main valve chamber 240, which can achieve precise pressure control.

[0034] Understandably, when the electromagnetic drive assembly 100 provides precise displacement output, the self-adaptive capability of the spherical seal 300's spherical surface to the orifice edge ensures reliable sealing in the closed position, while the linear change characteristic of the gap during opening guarantees precise and controllable flow regulation. The spherical geometry of the spherical seal 300 ensures that, when subjected to fluid pressure, the resultant pressure force points through the center of the sphere towards the axis 112 of the push rod device 110, preventing the generation of lateral torque that could cause the push rod device 110 to deflect. This reduces the risk of uneven wear and jamming during the push rod device 110's movement, further ensuring the accuracy and stability of displacement transmission by the electromagnetic drive assembly 100. This ensures the sealing reliability, adjustment accuracy, and excellent dynamic response of the entire pilot control system.

[0035] Please see Figures 1 to 2 In an optional embodiment of the present invention, the spherical seal 300 is made of a wear-resistant and corrosion-resistant material, and has a high-precision spherical outer surface and low surface roughness to ensure sealing performance when in contact with the bore edge. The spherical seal 300 is disposed at the end of the shaft 112 of the push rod device 110. Specifically, a retaining structure is provided at the end of the shaft 112 to fix the spherical seal 300. The retaining structure can be, for example, a flanged structure, that is, after the spherical seal 300 is installed at the end of the shaft 112, a flanged lip is formed at the end by spinning, stamping or rolling processes to wrap around part of the spherical surface of the spherical seal 300. This flanged structure can wrap around the spherical seal 300 circumferentially, firmly restricting the sphere to the end of the shaft 112 and preventing it from loosening or falling off in the axial and radial directions. The inner surface of the flanged structure fits well with the spherical surface of the spherical seal 300, ensuring reliable fixation without interfering with the line contact sealing function between the spherical seal 300 and the edge of the central hole 231. It is understood that the installation method of the spherical seal 300 is unrestricted, as long as stability and sealing effect under high pressure are ensured. In other embodiments, the retaining structure can also employ a snap ring or other forms, such as an annular groove machined at the shaft end, which presses the spherical seal 300 into the groove at the shaft end by inserting an open retaining ring to ensure a seal.

[0036] Please see Figures 1 to 2In an optional embodiment of the present invention, the diameter of the spherical seal 300 is larger than the diameter of the central hole 231, so that the sphere will not sink into the central hole 231 when in the closed position, thereby ensuring that the release force required when opening is small and the response speed is fast. The ratio of the diameter of the spherical seal 300 to the diameter of the central hole 231 is configured to a preset value, for example, between 1.1 and 1.8. This ratio range can be selected by comprehensively considering factors such as sealing specific pressure, opening force, and medium flow area. If the ratio is too small, the depth to which the sphere sinks into the central hole 231 when closed may increase the fluid viscous resistance to be overcome when opening, affecting the response speed; if the ratio is too large, the contact arc length of the sphere at the orifice is short, and the contact stress near the sealing line is high, which may aggravate contact fatigue. By reasonably setting this ratio, the requirements for sealing reliability and action sensitivity can be balanced. It should be noted that the specific ratio can be optimized and adjusted according to actual working conditions such as working pressure, medium viscosity, and hardness of sealing material.

[0037] Please see Figures 1 to 2 In an optional embodiment of the present invention, the end of the shaft 112 is provided with a shoulder step, and the spherical seal 300 is fitted onto the shaft 112 with its inner hole. The inner hole of the spherical seal 300 and the outer circle of the shaft 112 are fitted with a clearance fit to facilitate assembly. After the spherical seal 300 is assembled, the end of the shaft 112 is formed with a flanged structure through a flanged process, forming a lip that wraps around the spherical surface of the rear end portion of the spherical seal 300. This lip applies axial clamping pressure to provide auxiliary fixation and axially presses the rear end face of the spherical seal 300 against the end face of the shoulder step of the shaft 112, forming a tightly fitting annular end face seal. This ensures reliable connection and sealing, and blocks the leakage path of oil along the joint surface between the shaft and the spherical body. This effectively prevents leakage between the seal and the shaft 112 from causing a decrease in back pressure at the pilot valve of the solenoid valve, thereby reducing the overall pressure. Because the spherical body is rigidly constrained by the axial preload, it will not generate high-frequency self-excited vibration under high-pressure fluid pulses. Furthermore, to enhance the sealing effect between the spherical seal 300 and the shoulder step end face, one or more pre-tightening gaskets can be added between them. These pre-tightening gaskets can be made of a metal, spring steel, or engineering plastic with a hardness higher than that of the spherical seal 300. When the flange structure applies clamping pressure, the pre-tightening gaskets will undergo elastic compression deformation, applying a continuous and uniform axial pre-tightening force to the spherical seal 300. This further ensures the reliability of the end face seal, improves transmission accuracy and consistency of action response, and ensures that the orientation accuracy of the working spherical surface of the seal is not affected by the microscopic unevenness of the shoulder end face.

[0038] Please see Figures 1 to 2In an optional embodiment of the present invention, an annular groove or chamfer structure is provided at the end opening of the pilot valve cavity 250 and / or at the edge of the central hole 231 on the valve plate assembly 230, where the sealing seat surface that mates with the spherical seal 300 mates with the sealing seat surface. This annular groove or chamfer optimizes the contact form between the spherical seal 300 and the sealing seat surface, providing stable positioning guidance for the spherical seal 300. When the spherical seal 300 approaches the sealing position during movement, its spherical surface first contacts the edge of the annular groove or chamfer, and automatically slides into the optimal sealing position under the guidance of this edge, further enhancing its self-alignment and self-adaptation capabilities. This effectively solves the problem of misalignment of the sealing pair caused by machining and assembly errors. Through this sealing mating structure, the local sealing specific pressure is significantly improved under the same push rod force, enabling the formation of an effective initial seal under low pressure or a small spring force.

[0039] Please see Figures 1 to 2 In another optional embodiment of the present invention, the spherical seal 300 can also be fixed to the end of the shaft 112 of the push rod device 110 by welding. Specifically, the end of the shaft 112 is provided with a shoulder step, and the spherical seal 300 is fitted onto the shaft with its inner hole. The inner hole of the spherical seal 300 and the outer circle of the shaft 112 are clearance-fitted to facilitate assembly. After assembly, the rear end face of the spherical seal 300 fits against the end face of the shoulder step. Using laser welding technology, continuous or spot welding is performed along the annular area where the rear end face of the spherical seal 300 intersects with the end face of the shoulder step, causing micro-area melting of the metal material at the end face of the shoulder step, forming a metallurgical bond with the rear end face of the spherical seal 300, and firmly fixing the spherical seal 300 to the end face of the shoulder step. After welding, a non-removable annular sealing interface is formed between the spherical seal 300 and the shoulder step end face, effectively preventing leakage. Simultaneously, the welding fixing method provides reliable axial constraint for the spherical seal 300, preventing loosening, detachment, or self-excited vibration under high-pressure fluid impact or high-frequency operation. The working spherical surface of the spherical seal 300 maintains its complete geometric shape, enabling it to form a continuous closed annular line contact seal with the edge of the central hole 231 and the end of the pilot valve cavity 250 under assembly deviations or motion misalignment conditions.

[0040] Please see Figures 1 to 2In an optional embodiment of the present invention, when the electromagnetic drive assembly 100 is de-energized, the preload of the armature spring 113 causes the shaft 112 to drive the spherical seal 300 to press against the valve plate assembly 230. The spherical outer surface of the spherical seal 300 contacts the edge of the central hole 231 facing the pilot valve cavity 250, forming an annular line contact seal. At this time, the central hole 231 is closed by the spherical seal 300, cutting off the second pressure relief channel between the pilot valve cavity 250 and the pressure relief cavity 260 via the central hole 231. When the second pressure relief channel is closed, the third pressure relief channel automatically intervenes, ensuring the continuity of the pressure relief function and significantly improving the operational reliability of the valve.

[0041] Please see Figures 1 to 2 In an optional embodiment of the present invention, when the electromagnetic drive assembly 100 is energized, the electromagnetic force overcomes the force of the armature spring 113, attracting the armature 111 to drive the shaft 112 and the spherical seal 300 to move away from the central hole 231. The spherical seal 300 first leaves the central hole 231, the second pressure relief channel is opened, and the high-pressure medium in the pilot valve chamber 250 quickly flows into the pressure relief chamber 260 through the central hole 231 and is discharged to the low-pressure side. Since there is a throttling orifice between the pilot valve chamber 250 and the main valve chamber 240, the pressure in the pilot valve chamber 250 drops rapidly, causing the pressure in the main valve chamber 240 to be higher than the pressure in the pilot valve chamber 250. Under the action of the pressure difference, the valve core 212 overcomes the spring force and moves in the opening direction, opening the first pressure relief channel. The medium in the main valve chamber 240 is discharged through the valve hole, realizing the main pressure relief function. As the push rod device 110 continues to move, the spherical seal 300 moves further away from the central hole 231 and finally abuts against the edge of the pilot valve chamber 250 at the end away from the valve plate assembly 230, i.e., in the second position. Its spherical outer surface abuts against the edge of the pilot valve chamber 250 at the end away from the valve plate assembly 230, forming a seal and closing the orifice on this side. This blocks the direct communication between the pressure relief chamber 260 and the main valve chamber 240 through this end. The pilot valve chamber 250 can only maintain pressure contact with the main valve chamber 240 through the throttling orifice. Through the stable opening and pressure regulation of the main valve channel, full-flow pressure relief is achieved.

[0042] Please see Figures 1 to 2In an optional embodiment of the present invention, during operation, the line contact seal between the spherical seal 300 and the central hole 231 has self-centering and self-compensating characteristics. Even if there is a slight coaxiality deviation in the machining or assembly of the shaft 112, or if the shaft 112 experiences slight wobbling due to guide clearance during long-term movement, the spherical seal 300 can automatically adjust its contact posture under the action of spring force or fluid pressure to ensure that a uniform annular sealing line is formed between the spherical surface and the edge of the hole, ensuring zero leakage in the second pressure relief channel in the closed state and ensuring reliable pressure holding of the valve in the power-off state. During the opening process, the good linear relationship between the displacement of the spherical seal 300 and the flow area makes the adjustment of the pilot pressure relief flow rate precise and controllable, thereby realizing the proportional adjustment of the opening degree of the main valve core 212 and the system pressure. Thanks to the adaptive capability of the spherical seal 300 to a coaxial deviation of 112 degrees, and the comprehensive improvement effect of the spherical seal on the three leakage points, the sealing reliability of the valve is effectively maintained during long-term operation, the system leakage is greatly reduced, the performance in the low-pressure section remains stable, the pressure upper limit in the high-pressure section is significantly improved, and the pressure regulation range is significantly widened.

[0043] Please see Figures 1 to 2 It is understandable that the significant increase in the pressure range of the solenoid valve after adopting the 300mm spherical seal has important value in practical engineering applications. Taking vehicle shock absorbers as an example, the widening of the pressure range directly means a significant expansion of the damping force adjustment range: in the low pressure range, smaller damping forces can be achieved, allowing the suspension system to more fully absorb minor road vibrations during high-speed cruising and urban road conditions, improving ride comfort; in the high pressure range, larger damping forces can be output, effectively suppressing body roll, pitch, and bounce, significantly enhancing the vehicle's handling stability and body posture control capabilities during high-speed cornering, rapid acceleration, emergency braking, and off-road conditions. At the same time, the support of high pressure capacity allows the shock absorber to maintain stable damping output under extreme conditions such as heavy loads and strong impacts, protecting the suspension and body structure from severe impact damage.

[0044] Please see Figures 1 to 6 In an optional embodiment of the present invention, the use of a spherical seal 300 significantly expands the pressure range of the solenoid valve. For example... Figure 3 and Figure 4 The figures show the PQ diagrams for using annular seals at drive currents of 0.3A and 1.6A, respectively. It can be seen that the maximum pressure of the annular seal at 0.3A current is approximately 5 bar (50 LPM), and the maximum pressure of the annular seal at 1.6A current is approximately 80 bar (50 LPM). Figure 5 and Figure 6The test results are shown below, with the spherical seal 300 used under the same driving current conditions. The maximum pressure of the spherical seal 300 at 0.3A is still approximately 5 bar (50 LPM), while at 1.6A, the maximum pressure reaches approximately 155 bar (50 LPM). Comparing the test data clearly shows that under low current (0.3A) and low pressure conditions, the pressure values ​​of the two sealing methods are basically the same, both around 5 bar. This is because the leakage is small at low pressure, and the difference in sealing methods has no significant impact on the overall pressure. However, under high current (1.6A) and high pressure conditions, the pressure of the annular seal only reaches about 80 bar, while the pressure of the spherical seal 300 increases significantly to about 155 bar, nearly doubling. This is because, under high-pressure conditions, traditional annular planar seals suffer from low tolerance for misfitting due to rigid surface contact, uneven stress distribution under high pressure leading to local warping and deformation of the sealing surface, resulting in a sharp increase in leakage and severely limiting the upper pressure limit. In contrast, spherical seals, with their high sealing specific pressure generated by line contact, uniform stress and strong resistance to deformation under high pressure due to their spherical rotational symmetry structure, and natural self-aligning ability to automatically compensate for assembly deviations, effectively suppress leakage under high pressure, allowing the upper pressure limit to be significantly exceeded, thereby effectively expanding the working pressure range of the solenoid valve.

[0045] In summary, the solenoid valve of this invention, through the cooperation of the electromagnetic drive assembly 100, the overflow valve assembly 200, and the spherical seal 300, constructs a fluid pressure control and pressure relief system that is reliable in sealing, precise in regulation, and highly resistant to contamination. The dual-position line contact sealing structure formed by the spherical seal 300, the central hole 231 of the valve plate assembly 230, and the end of the pilot valve chamber 250, with its excellent coaxial 112-degree deviation self-adaptation capability and wear uniformity characteristics, fundamentally solves the leakage problem caused by machining and assembly deviations or long-term wear in traditional seals, significantly improving the valve's sealing reliability and service life, while greatly expanding the pressure regulation range. The multi-pressure relief channel design provides multiple pressure relief guarantees for the valve, further improving its operational reliability under complex working conditions. The proportional displacement control of the electromagnetic drive assembly 100 and the linear flow regulation characteristics of the spherical seal 300 work together to achieve precise proportional control of the system pressure. Through the above structural design, the solenoid valve of this invention has achieved significant progress in sealing reliability, dynamic response characteristics, and pressure control accuracy.

[0046] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

[0047] Throughout this description, numerous specific details, such as examples of components and / or methods, are provided to provide a complete understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention may be practiced without one or more of these specific details or by other devices, systems, components, methods, parts, materials, components, etc. In other instances, well-known structures, materials, or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0048] Throughout this specification, the terms "an embodiment," "embodiment," or "specific embodiment" refer to a particular feature, structure, or characteristic described in connection with an embodiment that is included in at least one embodiment of the invention, but not necessarily in all embodiments. Therefore, the various representations of the phrases "in one embodiment," "in an embodiment," or "in a specific embodiment" in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic of any specific embodiment of the invention can be combined with one or more other embodiments in any suitable manner. It should be understood that other variations and modifications of the embodiments of the invention described and illustrated herein may be based on the teachings herein and will be considered part of the spirit and scope of the invention.

[0049] It should also be understood that one or more of the elements shown in the figures may be implemented in a more separate or more integrated manner, or may even be removed because they are inoperable in certain circumstances or provided because they may be useful for a particular application.

[0050] Furthermore, unless otherwise expressly stated, any arrows in the accompanying drawings should be considered illustrative only and not limiting. Additionally, unless otherwise stated, the term "or" as used herein is generally intended to mean "and / or". Where a term is anticipated to provide a separation or combination capability that is unclear, a combination of components or steps will also be considered as indicated.

[0051] As used herein and throughout the claims below, unless otherwise specified, “a” and “the” include the plural references. Similarly, as used herein and throughout the claims below, unless otherwise specified, “in” means “in” and “on”.

[0052] The above description of the embodiments shown in this invention (including the content set forth in the abstract of the specification) is not intended to be an exhaustive enumeration or to limit the invention to the precise forms disclosed herein. Although specific embodiments and examples of the invention have been described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the invention, as will be recognized and understood by those skilled in the art. As indicated, these modifications can be made to the invention in accordance with the above description of the embodiments described herein, and such modifications will be within the spirit and scope of the invention.

[0053] This document has generally described the systems and methods in detail to aid in understanding the invention. Furthermore, various specific details have been set forth to provide a general understanding of embodiments of the invention. However, those skilled in the art will recognize that embodiments of the invention can be practiced without one or more specific details, or using other means, systems, accessories, methods, components, materials, parts, etc. In other instances, well-known structures, materials, and / or operations have not been specifically shown or described in detail to avoid obscuring aspects of embodiments of the invention.

[0054] Therefore, although the invention has been described herein with reference to specific embodiments thereof, freedom of modification, various changes and substitutions are also within the scope of the foregoing disclosure, and it should be understood that in some cases, certain features of the invention may be adopted without departing from the scope and spirit of the invention and without corresponding use of other features. Thus, many modifications can be made to adapt a particular environment or material to the essential scope and spirit of the invention. The invention is not intended to be limited to the specific terminology used in the following claims and / or the specific embodiments disclosed as the best mode for carrying out the invention, but the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Therefore, the scope of the invention will be defined only by the appended claims.

Claims

1. A solenoid valve, characterized in that, include: An electromagnetic drive assembly, the electromagnetic drive assembly including a push rod device movable in an axial direction; An overflow valve assembly is connected to one end of the electromagnetic drive assembly. The overflow valve assembly includes a main valve assembly, a pilot valve assembly, and a valve plate assembly, and forms a main valve chamber, a pilot valve chamber, and a pressure relief chamber. The main valve chamber is connected to the pilot valve chamber, and the pilot valve chamber is separated from the pressure relief chamber by the valve plate assembly. The valve plate assembly has a central hole, and the push rod device passes through the central hole and extends to one side of the pilot valve chamber. A spherical seal is disposed at the end of the push rod device. The push rod device fixes the spherical seal by a retaining structure formed at its end, or the spherical seal is welded to the end of the push rod device. The spherical seal is configured to move between a first position and a second position under the action of the push rod device. When the spherical seal is in the first position, it seals the central hole to cut off the communication between the pilot valve chamber and the pressure relief chamber. When the spherical seal is in the second position, it seals one end of the pilot valve chamber to cut off the communication between the pilot valve chamber and the pressure relief chamber.

2. The solenoid valve according to claim 1, characterized in that, The main valve assembly includes: The valve body has one end connected to the electromagnetic drive assembly and the other end provided with a liquid inlet. The valve body has a valve hole on its side. A valve core is axially movable within the valve body to connect or disconnect the first pressure relief channel formed when the inlet is connected to the valve hole. The main valve chamber is formed within the valve core and is connected to the inlet.

3. The solenoid valve according to claim 1, characterized in that, The pilot valve assembly is disposed in the main valve chamber, and its interior is hollow to form the pilot valve chamber. The pilot valve chamber and the main valve chamber are kept in communication through a throttling orifice. The spherical seal is configured to be axially displaced under the action of the push rod device to connect or disconnect the second pressure relief channel formed when the pilot valve chamber is connected to the pressure relief chamber, or to continuously adjust the flow area of ​​the second pressure relief channel.

4. The solenoid valve according to claim 1, characterized in that, The valve plate assembly includes: A valve plate body is disposed between the pilot valve assembly and the electromagnetic drive assembly. The side of the valve plate body opposite to the pilot valve assembly forms the pressure relief chamber. The valve plate body is provided with a flow hole that extends axially and is used to connect the pilot valve chamber and the pressure relief chamber. An elastic element is disposed on the side of the valve plate away from the spherical seal. The elastic element covers the flow hole by applying a pre-tightening force to the valve plate, and is used to connect or disconnect the pilot valve cavity and the third pressure relief channel formed when the flow hole and the pressure relief cavity are connected.

5. The solenoid valve according to claim 1, characterized in that, The spherical seal has a spherical outer surface, which forms a line contact seal with the central hole and the edge of the pilot valve cavity.

6. The solenoid valve according to claim 1, characterized in that, The retaining structure includes a flange structure that wraps around a portion of the spherical seal.

7. The solenoid valve according to claim 1, characterized in that, The diameter of the spherical seal is larger than the diameter of the central hole, and the ratio of the diameter of the spherical seal to the diameter of the central hole is configured to a preset value.

8. The solenoid valve according to claim 6, characterized in that, The electromagnetic drive assembly further includes a housing and a coil, and the push rod device includes: An armature is disposed within the housing; A shaft is connected to the housing via the armature. An armature spring is provided axially between the armature and the housing. The armature spring applies a preload force to the shaft, which tends to press the spherical seal against the central hole. When the coil is energized, it drives the shaft to move the spherical seal between the first position and the second position. When the power is off, the shaft and the spherical seal at its end move to the first position under the action of the armature spring and seal the center hole.

9. The solenoid valve according to claim 8, characterized in that, The shaft has a shoulder step at its end. The spherical seal is axially pressed against the end face of the shoulder step under the buckling pressure of the flange structure, or the spherical seal is axially fixed to the end face of the shoulder step by welding.

10. The solenoid valve according to claim 1, characterized in that, The pilot valve cavity and / or the end of the central hole that mates with the spherical seal is provided with an annular groove or a chamfer.

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