solenoid valve

Abstract

The utility model belongs to solenoid valve technical field, specifically provides a solenoid valve. The utility model aims at solving the problem that the solenoid current is larger when the existing solenoid valve maintains the gas path open for a long time. For this purpose, the solenoid valve of the utility model includes valve body assembly, valve core subassembly, reset spring and solenoid. The valve body assembly is defined with air inlet, air outlet and accommodating cavity, and the valve body assembly includes static iron core and permanent magnet, and the static iron core is located at the side of the accommodating cavity away from the air inlet. The valve core subassembly is movably arranged in the accommodating cavity. The reset spring is arranged between the valve body assembly and the valve core subassembly to drive the valve core subassembly to block the gas path between the air inlet and the air outlet. The solenoid is fixedly connected with the valve body assembly and drives the valve core subassembly to open the gas path between the air inlet and the air outlet, and thus the permanent magnet attracts the valve core subassembly to reduce the current of the solenoid to keep the valve core subassembly open. The utility model overcomes the above technical problems.

Description

Technical Field

[0001] This utility model belongs to the field of electromagnetic valve technology, and specifically provides an electromagnetic valve. Background Technology

[0002] This utility model belongs to the field of solenoid valve technology, specifically providing a solenoid valve. Solenoid valves, as actuators for controlling the opening and closing of air passages, are widely used in industrial control, rail transportation, automobiles, and other fields. A solenoid valve typically includes a valve body assembly, a valve core assembly, a solenoid coil, and a return spring. The electromagnetic force generated by energizing the solenoid coil drives the valve core assembly to move, thereby opening or blocking the air passage. After de-energization, the return spring drives the valve core assembly to reset.

[0003] In practical applications, some scenarios require solenoid valves to maintain the air circuit open for extended periods. To achieve this holding function, traditional solenoid valves require a continuous supply of a large current to the solenoid coil to generate sufficient electromagnetic force to balance the spring force of the return spring. This results in high energy consumption for the solenoid valve, and prolonged energization can lead to high coil power consumption, severe heat generation, premature aging, and shortened service life. It also increases the burden on the power supply system. Utility Model Content

[0004] One objective of this invention is to solve the problem of excessive electromagnetic coil current in existing solenoid valves when maintaining the air circuit open for extended periods.

[0005] To achieve the above objectives, this utility model provides a solenoid valve, comprising: A valve body assembly defines an air inlet, an air outlet, and a receiving cavity. The valve body assembly includes a stationary iron core and a permanent magnet fixed on the stationary iron core. The stationary iron core is located on the side of the receiving cavity away from the air inlet. The valve core assembly is movably disposed within the receiving cavity; A return spring is disposed between the valve body assembly and the valve core assembly to drive the valve core assembly to block the air passage between the air inlet and the air outlet; An electromagnetic coil, fixedly connected to the valve body assembly, generates a magnetic field acting on the stationary iron core and the valve core assembly to overcome the resistance of the return spring, drive the valve core assembly to open the air passage between the air inlet and the air outlet, and thus cause the permanent magnet to attract the valve core assembly, thereby reducing the current required by the electromagnetic coil to keep the valve core assembly open.

[0006] Optionally, the stationary iron core is provided with an insert groove, and the permanent magnet is embedded in the insert groove.

[0007] Optionally, both the mounting slot and the permanent magnet are configured as annular.

[0008] Optionally, the stationary iron core is further provided with a spring positioning hole to accommodate a portion of the reset spring; the spring positioning hole is located within the mounting groove.

[0009] Optionally, the ratio of the outer diameter of the permanent magnet to the outer diameter of the stationary iron core is selected from any value from 0.2 to 1; and / or, the ratio of the outer diameter of the permanent magnet to the thickness of the permanent magnet is selected from any value from 0.5 to 2.

[0010] Optionally, the saturation magnetic induction intensity of the permanent magnet is selected from any value from 0.8T to 1.5T.

[0011] Optionally, the valve core assembly includes a moving iron core and a valve plug fixedly connected to the moving iron core, so that the valve core assembly blocks the air passage between the air inlet and the air outlet through the valve plug; the moving iron core divides the receiving cavity into an inlet / outlet communication area and an isolation area, the inlet / outlet communication area being connected to the air inlet and the air outlet respectively; the moving iron core is provided with a damping channel to impede the movement of the valve core assembly, thereby reducing the impact of the valve core assembly on the valve body assembly.

[0012] Optionally, the ratio of the flow area of ​​the damping channel to the cross-sectional area of ​​the isolation zone is selected from any value between 1‰ and 10‰, so that the isolation zone can achieve air pressure balance with the inlet and outlet communication area while being able to travel the positive pressure air spring and the negative pressure air spring, thereby preventing the valve core assembly from jumping.

[0013] Optionally, a blind hole is provided on the side of the moving iron core away from the valve plug, and the blind hole accommodates a portion of the return spring.

[0014] Optionally, the solenoid valve is suitable for adjusting the stiffness of the air spring.

[0015] Based on the foregoing description, those skilled in the art will understand that in the aforementioned technical solution of this utility model, by fixing a permanent magnet on the stationary iron core, when the electromagnetic coil is energized to open the valve core assembly, the permanent magnet attracts the valve core assembly, thereby reducing the current required by the electromagnetic coil to keep the valve core assembly open.

[0016] Other beneficial effects of this utility model will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can more clearly understand the improvement purpose, features and advantages of this utility model. Attached Figure Description

[0017] To more clearly illustrate the technical solution of this utility model, some embodiments of this utility model will be described below with reference to the accompanying drawings. Those skilled in the art should understand that the same reference numerals may indicate the same or similar components or parts in different drawings; the drawings of this utility model are not necessarily drawn to scale. In the drawings: Figure 1 This is an exploded view (first isometric view) of the solenoid valve in some embodiments of this utility model. Figure 2 This is an exploded view (second isometric view) of the solenoid valve in some embodiments of this utility model. Figure 3 This is a perspective view of the solenoid valve in some embodiments of this utility model; Figure 4 This is a radial view of the solenoid valve in some embodiments of this utility model; Figure 5 yes Figure 4 A cross-sectional view along the AA direction when the solenoid valve is de-energized; Figure 6 yes Figure 4 A cross-sectional view along the AA direction when the solenoid valve is energized (the coil assembly is hidden). Figure 7 yes Figure 4 A cross-sectional view of the solenoid valve along the AA direction as the valve core assembly moves; Figure 8 This is a perspective view of the valve core assembly in some other embodiments of this utility model; Figure 9 This is a cross-sectional view of the valve core assembly in some embodiments of the present invention.

[0018] Explanation of reference numerals in the attached figures: 001. Solenoid valve; 100. Valve body assembly; 101. Air inlet; 102. Air outlet; 103. Receiving cavity; 1031. Inlet / outlet connection area; 1032. Isolation area; 110. Valve nozzle; 120. Connecting pipe; 130. Magnetic guide ring tube; 140. Magnetic shielding tube; 150. Static iron core; 151. Embedding groove; 152. Spring positioning hole; 160. Permanent magnet; 200. Valve core assembly; 201. Damping channel; 210. Moving iron core; 211. Blind hole; 212. Angled hole; 213. Groove; 214. Straight hole; 220. Valve plug; 300. Return spring; 400. Coil assembly; 410. Electromagnetic coil; 420. Coil bracket; 430. Coil housing; o, Axial direction. Detailed Implementation

[0019] Those skilled in the art should understand that the embodiments described below are merely some embodiments of the present invention, and not all embodiments of the present invention. These embodiments are intended to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by those skilled in the art without creative effort should still fall within the scope of protection of the present invention.

[0020] It should be noted that in the description of this utility model, terms such as "center," "upper," "lower," "top," "bottom," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the corresponding device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0021] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances. For example, unless otherwise specified, the terms "installation," "connection," "joining," and "fixing" can specifically refer to any feasible connection form such as bolt connection, screw connection, welding, insertion, riveting, fusion welding, or snap-fit.

[0022] like Figures 1 to 5 As shown, in some embodiments of this utility model, the solenoid valve 001 includes a valve body assembly 100, a valve core assembly 200, a return spring 300, and a coil assembly 400.

[0023] like Figures 1 to 5 As shown, in some embodiments of the present invention, the valve body assembly 100 defines an air inlet 101, an air outlet 102, and a receiving cavity 103. The valve body assembly 100 includes a stationary iron core 150 and a permanent magnet 160 fixed on the stationary iron core 150, the stationary iron core 150 being located on the side of the receiving cavity 103 away from the air inlet 101.

[0024] like Figure 5As shown, in some embodiments of this utility model, the valve core assembly 200 is movably disposed in the receiving cavity 103, dividing the receiving cavity 103 into an inlet / outlet communication area 1031 and an isolation area 1032. The inlet / outlet communication area 1031 is connected to the air inlet 101 and the air outlet 102, respectively. The valve core assembly 200 is used to block the air passage between the air inlet 101 and the air outlet 102 (i.e., to disconnect the air inlet 101 from the air outlet 102). The valve core assembly 200 is provided with a damping channel 201 connecting the inlet / outlet communication area 1031 and the isolation area 1032 to provide damping force to the gas flowing into and out of the isolation area 1032, thereby hindering the movement of the valve core assembly 200 and reducing the impact of the valve core assembly 200 on the valve body assembly 100.

[0025] like Figure 5 As shown, the reset spring 300 is disposed between the valve body assembly 100 and the valve core assembly 200 to drive the valve core assembly 200 to block the air passage between the air inlet 101 and the air outlet 102.

[0026] like Figures 3 to 5 As shown, the coil assembly 400 is disposed outside the valve body assembly 100 and includes an electromagnetic coil 410. The electromagnetic coil 410 is capable of generating a magnetic field acting on the stationary iron core 150 and the valve core assembly 200 to overcome the resistance of the return spring 300, drive the valve core assembly 200 to open the air passage between the air inlet 101 and the air outlet 102 (i.e., connect the air inlet 101 and the air outlet 102), and thus cause the permanent magnet 160 to attract the valve core assembly 200, thereby reducing the current required by the electromagnetic coil 410 to keep the valve core assembly 200 open.

[0027] Those skilled in the art will understand that by fixing a permanent magnet 160 on the stationary iron core 150, when the electromagnetic coil 410 is energized to open the valve core assembly 200, the permanent magnet 160 can attract the valve core assembly 200, thereby reducing the current required by the electromagnetic coil 410 to keep the valve core assembly 200 open.

[0028] like Figure 1 , Figure 2 and Figure 5 As shown, in some embodiments of this utility model, the valve body assembly 100 includes a valve nozzle 110, a connecting pipe 120, a magnetic ring pipe 130, a magnetic shielding pipe 140, and a stationary iron core 150 arranged sequentially. Any two adjacent valve nozzles 110, connecting pipes 120, magnetic ring pipes 130, magnetic shielding pipes 140, and stationary iron core 150 are fixedly connected or integrally formed.

[0029] Among them, the fixed connection can be any feasible connection method such as welding, interference fit, threaded connection, etc.

[0030] from Figure 1 , Figure 2 and Figure 5As can be seen, the air inlet 101 is formed on the valve nozzle 110, and the air outlet 102 is formed on the connecting pipe 120. The valve nozzle 110, the connecting pipe 120, the magnetic ring pipe 130, the magnetic shielding pipe 140, and the stationary iron core 150 together define the receiving cavity 103.

[0031] In addition, in other embodiments of this utility model, those skilled in the art may, as needed, form the air inlet 101 on the connecting pipe 120 and the air outlet 102 on the valve nozzle 110.

[0032] like Figure 1 , Figure 2 and Figure 5 As shown, in some embodiments of the present invention, the valve body assembly 100 further includes a permanent magnet 160 fixed on a stationary iron core 150, which is located on the side of the receiving cavity 103 away from the air inlet 101, so that the permanent magnet 160 can attract the valve core assembly 200, specifically attracting the moving iron core 210.

[0033] like Figure 6 As shown, when the coil assembly 400 is energized to drive the valve core assembly 200 to open the air passage between the air inlet 101 and the air outlet 102, the permanent magnet 160 attracts the valve core assembly 200, reducing the current required by the coil assembly 400 to keep the valve core assembly 200 open. This reduces the heat generated by the coil assembly 400.

[0034] In some embodiments of this utility model, the permanent magnet 160 can be a ferrite magnet, a samarium cobalt magnet, a neodymium iron boron magnet, an alnico magnet, etc.

[0035] like Figure 1 and Figure 5 As shown, in some embodiments of this utility model, the stationary iron core 150 is provided with an insert groove 151, and the permanent magnet 160 is inserted into the insert groove 151 to facilitate the fixation of the permanent magnet 160.

[0036] from Figure 1 As can be seen, both the mounting slot 151 and the permanent magnet 160 are set as annular.

[0037] like Figure 1 and Figure 5 As shown, in some embodiments of this utility model, the stationary iron core 150 abuts against the return spring 300. Specifically, the stationary iron core 150 is also provided with a spring positioning hole 152 to accommodate a portion of the return spring 300. The spring positioning hole 152 is located within the mounting groove 151 to improve the space utilization of the stationary iron core 150.

[0038] like Figure 7As shown, in some embodiments of this utility model, the ratio of the outer diameter d of the permanent magnet 160 to the outer diameter D of the stationary iron core 150 is selected from any value from 0.2 to 1, specifically any feasible value such as 0.2, 0.3, 0.35, 0.4, 0.5, 0.56, 0.6, 0.7, 0.8, 0.9, 1, etc.

[0039] Continue reading Figure 7 In some embodiments of this utility model, the ratio of the outer diameter of the permanent magnet 160 to the thickness of the permanent magnet 160 is selected from any value from 0.5 to 2, specifically any feasible value such as 0.5, 0.56, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.3, 1.6, 1.8, 2, etc.

[0040] Furthermore, the saturation magnetic induction intensity of the permanent magnet 160 is selected from any value between 0.8T and 1.5T, so that when the coil assembly 400 is energized, the permanent magnet 160 provides sufficient magnetic attraction to the moving iron core 210. At the same time, it also avoids the permanent magnet 160 having excessive attraction, which would prevent the return spring 300 from driving the valve core assembly 200 to reset.

[0041] like Figure 1 , Figure 2 and Figure 5 As shown, in some embodiments of this utility model, the valve core assembly 200 includes a moving iron core 210 and a valve plug 220 fixedly connected to the moving iron core 210, so that the valve core assembly 200 blocks the air passage between the air inlet 101 and the air outlet 102 through the valve plug 220.

[0042] from Figure 5 As can be seen, the moving iron core 210 is provided with an annular groove (not marked in the figure), and the valve plug 220 is sleeved on the moving iron core 210 and is provided with an inner annular protrusion (not marked in the figure), which is embedded in the annular groove.

[0043] from Figure 5 It can also be seen that the damping channel 201 is set on the moving iron core 210.

[0044] Furthermore, the ratio of the flow area of ​​the damping channel 201 to the cross-sectional area of ​​the isolation zone 1032 is selected from any value between 1‰ and 10‰ to ensure the damping effect of the damping channel 201 on the movement of the valve core assembly 200.

[0045] In some embodiments of this utility model, the ratio of the flow area of ​​the damping channel 201 to the cross-sectional area of ​​the isolation zone 1032 can be any feasible value such as 1‰, 1.5‰, 2‰, 2.3‰, 3‰, 4‰, 5‰, 6.5‰, 7‰, 8‰, 10‰, etc.

[0046] Those skilled in the art will understand that by selecting a ratio of the flow area of ​​the damping channel 201 to the cross-sectional area of ​​the isolation zone 1032 from any value between 1‰ and 10‰, the damping effect of the damping channel 201 on the movement of the valve core assembly 200 is ensured. This is because, during the movement of the valve core, the volume of the isolation zone 1032 rapidly decreases or increases, requiring the isolation zone 1032 to release or absorb a large amount of gas. However, due to the small flow area of ​​the damping channel 201, the flow rate of gas flowing into or out of the isolation zone 1032 is small, insufficient to meet the needs of the isolation zone 1032. Consequently, at the moment the valve core assembly 200 opens or closes, the isolation zone 1032 forms a positive pressure air spring due to a rapid increase in gas and a negative pressure air spring due to a rapid decrease in gas, thereby hindering the movement of the valve core assembly 200. As the gas flows through the damping channel 201, the gas pressure in the isolation zone 1032 will be balanced with the gas pressure in the inlet and outlet connection zone 1031 after the valve core assembly 200 is opened or closed, thereby ensuring the performance of the solenoid valve 001 when it is open and its blocking performance when it is closed.

[0047] Those skilled in the art will also understand that if the ratio of the flow area of ​​the damping channel 201 to the cross-sectional area of ​​the isolation zone 1032 is too small, the high-pressure gas in the isolation zone 1032 will not be able to be discharged in time. Since air has good deformation elasticity, it is easy for the valve core assembly 200 to bounce back and forth under the action of the electromagnetic coil 410 and the high-pressure gas (positive pressure air spring). Similarly, it will also cause the negative pressure in the isolation zone 1032 to not be replenished by air in time, causing the valve core assembly 200 to bounce back and forth under the action of the return spring 300 and the negative pressure (negative pressure air spring) in the isolation zone 1032.

[0048] Furthermore, the ratio of the flow area of ​​the damping channel 201 to the cross-sectional area of ​​the isolation zone 1032 is selected from any value between 2‰ and 5‰, and the maximum stroke of the valve core assembly 200 is less than or equal to 3 mm to ensure the response speed when the valve core assembly 200 moves.

[0049] Among them, the maximum stroke of the valve core assembly 200 is the valve core assembly 200 from Figure 5 Move to the position shown Figure 6 The distance moved to the position shown.

[0050] like Figure 2 and Figure 5 As shown, in some embodiments of this utility model, a blind hole 211 is provided on the side of the moving iron core 210 away from the valve plug 220, and the blind hole 211 accommodates a portion of the return spring 300. The damping channel 201 includes at least one oblique hole 212 communicating with the blind hole 211, and the end of the oblique hole 212 away from the blind hole 211 is connected to the inlet and outlet communication area 1031.

[0051] Those skilled in the art will understand that by setting the damping channel 201 as an oblique hole 212 communicating with the blind hole 211, the length of the damping channel 201 is shortened, making the processing of the damping channel 201 simpler.

[0052] Furthermore, in other embodiments of this utility model, those skilled in the art can also configure the damping channel 201 in any other arbitrary form as needed. See below for reference. Figure 8 and Figure 9 Let me give an example.

[0053] like Figure 8 As shown, in some other embodiments of this utility model, those skilled in the art can also make the damping channel 201 include at least one groove 213 formed on the outer peripheral surface of the moving iron core 210 as needed, so as to facilitate the processing of the damping channel 201.

[0054] Furthermore, the groove 213 is not limited to Figure 8 The straight line shape shown can also be a spiral, wavy, or other form of groove structure.

[0055] like Figure 8 As shown, in some other embodiments of this utility model, there are at least two grooves 213, and they are symmetrical about the axis of the moving iron core 210, so as to maintain the concentricity of the valve core assembly 200 and the valve body assembly 100 by the high-pressure gas in the at least two grooves 213.

[0056] Those skilled in the art will understand that during the movement of the valve core assembly 200, the high-pressure gas flowing through the groove 213 will form an air layer between the valve core assembly 200 and the valve body assembly 100, and support the valve core assembly 200 to prevent the valve core assembly 200 from being eccentric.

[0057] like Figure 9 As shown, in some embodiments of the present invention, the damping channel 201 includes at least one straight hole 214 that penetrates the moving iron core 210 along the axial direction.

[0058] like Figure 5 As shown, in some embodiments of this utility model, the coil assembly 400 includes an electromagnetic coil 410, a coil support 420, and a coil housing 430. The electromagnetic coil 410 is mounted on the coil support 420, and the coil housing 430 is sleeved on the outside of the electromagnetic coil 410 and the coil support 420. The electromagnetic coil 410 is mounted on the valve body assembly 100 via the coil support 420.

[0059] The following reference Figures 5 to 7 The working principle of the solenoid valve 001 in some embodiments of this utility model will be briefly explained below.

[0060] like Figure 5 As shown, when the solenoid valve 001 is de-energized, the solenoid coil 410 does not generate a magnetic field. The valve core assembly 200 abuts against the valve nozzle 110 under the action of the return spring 300, thereby blocking the air passage between the air inlet 101 and the air outlet 102.

[0061] When solenoid valve 001 is energized, solenoid coil 410 generates a magnetic field, causing the stationary iron core 150 and moving iron core 210 to attract each other. This force overcomes the spring force of return spring 300, driving valve core assembly 200 via... Figure 5 and Figure 7 Move the position to Figure 6 The position is shown. During this process, the gas in the isolation zone 1032 is rapidly compressed, forming high pressure, which can hinder the movement of the valve core assembly 200 and weaken the impact of the valve core assembly 200 on the valve body assembly 100. At the same time, due to the presence of the damping channel 201, the high-pressure gas in the isolation zone 1032 will slowly flow to the inlet and outlet connecting area 1031 until the gas pressure between the isolation zone 1032 and the inlet and outlet connecting area 1031 is equal.

[0062] like Figure 6 As shown, when the solenoid valve 001 is energized, the solenoid coil 410 generates a magnetic field, causing the stationary iron core 150 and the moving iron core 210 to attract each other and move closer together, thus moving the valve core assembly 200 away from the valve nozzle 110 to open the air passage between the air inlet 101 and the air outlet 102. Simultaneously, the permanent magnet 160 also attracts the stationary iron core 150, thereby offsetting part of the spring force of the return spring 300 to replace part of the electromagnetic force generated by the solenoid coil 410, reducing the current in the solenoid coil 410.

[0063] When solenoid valve 001 is de-energized, valve core assembly 200, under the action of return spring 300, via... Figure 6 and Figure 7 Move the position to Figure 5 The position is shown. During this process, the volume of the isolation zone 1032 rapidly increases, creating a negative pressure that hinders the movement of the valve core assembly 200 and weakens the impact of the valve core assembly 200 on the valve body assembly 100. Simultaneously, due to the presence of the damping channel 201, the gas in the inlet / outlet communication zone 1031 slowly flows towards the isolation zone 1032 until the gas pressure between the isolation zone 1032 and the inlet / outlet communication zone 1031 is equal.

[0064] Based on the foregoing description, those skilled in the art will understand that the solenoid valve 001 of this utility model can not only reduce the impact of the valve core assembly 200 on the valve body assembly 100 and reduce the working noise of the solenoid valve 001, but also reduce the holding current of the solenoid coil 410 and reduce the heat generation of the solenoid valve 001.

[0065] Furthermore, the solenoid valve 001 described in any of the preceding embodiments of this utility model can be used to adjust the stiffness of the air spring and can be installed in a car.

[0066] The technical solution of this utility model has been described in conjunction with several embodiments above. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is not limited to these specific embodiments. Without departing from the technical principles of this utility model, those skilled in the art can disassemble and combine the technical solutions in the above embodiments, and can also make equivalent changes or substitutions to the relevant technical features. Any changes, equivalent substitutions, improvements, etc., made within the technical concept and / or technical principles of this utility model will fall within the protection scope of this utility model.

[0067] Finally, it should be noted that in this invention, the term "connection" refers to fluid communication, allowing fluids (e.g., air, liquid) to flow between two interconnected entities. Furthermore, this "connection" can be either a leak-free flow of fluid between two interconnected entities, or a flow with slight leakage of fluid between two interconnected entities.

Claims

1. A solenoid valve, characterized in that, include: A valve body assembly defines an air inlet, an air outlet, and a receiving cavity. The valve body assembly includes a stationary iron core and a permanent magnet fixed on the stationary iron core. The stationary iron core is located on the side of the receiving cavity away from the air inlet. The valve core assembly is movably disposed within the receiving cavity; A return spring is disposed between the valve body assembly and the valve core assembly to drive the valve core assembly to block the air passage between the air inlet and the air outlet; An electromagnetic coil, fixedly connected to the valve body assembly, generates a magnetic field acting on the stationary iron core and the valve core assembly to overcome the resistance of the return spring, drive the valve core assembly to open the air passage between the air inlet and the air outlet, and thus cause the permanent magnet to attract the valve core assembly, thereby reducing the current required by the electromagnetic coil to keep the valve core assembly open.

2. The solenoid valve according to claim 1, characterized in that, The stationary iron core is provided with an insert groove. The permanent magnet is embedded in the mounting slot.

3. The solenoid valve according to claim 2, characterized in that, Both the mounting slot and the permanent magnet are configured as rings.

4. The solenoid valve according to claim 3, characterized in that, The stationary iron core is also provided with a spring positioning hole to accommodate a part of the return spring; The spring positioning hole is located within the mounting slot.

5. The solenoid valve according to any one of claims 1 to 4, characterized in that, The ratio of the outer diameter of the permanent magnet to the outer diameter of the stationary iron core is selected from any value between 0.2 and 1; and / or, The ratio of the outer diameter of the permanent magnet to the thickness of the permanent magnet is selected from any value between 0.5 and 2.

6. The solenoid valve according to any one of claims 1 to 4, characterized in that, The saturation magnetic induction intensity of the permanent magnet is selected from any value between 0.8T and 1.5T.

7. The solenoid valve according to any one of claims 1 to 4, characterized in that, The valve core assembly includes a moving iron core and a valve plug fixedly connected to the moving iron core, so that the valve core assembly blocks the air passage between the air inlet and the air outlet through the valve plug; The moving iron core divides the accommodating cavity into an inlet / outlet communication area and an isolation area, and the inlet / outlet communication area is connected to the air inlet and the air outlet respectively; The moving iron core is provided with a damping channel to impede the movement of the valve core assembly, thereby reducing the impact of the valve core assembly on the valve body assembly.

8. The solenoid valve according to claim 7, characterized in that, The ratio of the flow area of ​​the damping channel to the cross-sectional area of ​​the isolation zone is selected from any value between 1‰ and 10‰, so that the isolation zone can achieve air pressure balance with the inlet and outlet communication area while being able to travel positive and negative pressure air springs, thus preventing the valve core assembly from jumping.

9. The solenoid valve according to claim 7, characterized in that, A blind hole is provided on the side of the moving iron core away from the valve plug, and the blind hole accommodates a portion of the return spring.

10. The solenoid valve according to any one of claims 1 to 4, characterized in that, The solenoid valve is used to adjust the stiffness of the air spring.

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