CN219140002U - Normally closed electromagnetic valve - Google Patents

Abstract

The utility model provides a normally closed electromagnetic valve, which comprises a shell, a static iron core and a movable iron core component. The shell is provided with a containing cavity and a first channel and a second channel, wherein the first channel is communicated with the containing cavity. The static iron core is at least partially positioned in the accommodating cavity and fixedly connected with the shell. The movable iron core component is arranged in the accommodating cavity and comprises a movable iron core, a valve needle and an elastic piece, wherein the movable iron core is positioned on one side of the static iron core and is provided with a cavity, and a reset spring is arranged between the movable iron core and the static iron core. The valve needle includes a first valve needle portion and a second valve needle portion, the first valve needle portion being located within the cavity and the second valve needle portion being located at least partially outside the cavity. The elastic piece is located the cavity, and the both ends of elastic piece butt first needle portion respectively move the iron core, and the elastic piece pushes away first needle portion towards the direction of keeping away from quiet iron core, moves the iron core subassembly and can be driven thereby by drive assembly and remove between the closed position that makes second needle portion seal the second passageway and the open position that makes second needle portion open the second passageway and communicate with holding the chamber.

Description

Normally closed electromagnetic valve

Technical Field

The present utility model relates generally to the technical field of solenoid valves, and more particularly to a normally closed solenoid valve.

Background

The working condition pressure of the hydraulic system is large, the pressure difference between valve cavity channels of the electromagnetic valve is large, and the valve core ball body and the valve seat collide and rub to generate working condition noise. Solenoid valves for vehicles are required to meet the requirements of compact structure, stable performance and low noise.

Accordingly, it is desirable to provide a normally closed solenoid valve that at least partially addresses the above-described problems.

Disclosure of Invention

In the summary, a series of concepts in a simplified form are introduced, which will be further described in detail in the detailed description. The summary of the utility model is not intended to define the key features and essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

To at least partially solve the above problems, the present utility model provides a normally closed solenoid valve including:

the shell is provided with a containing cavity and a first channel and a second channel, and the first channel is communicated with the containing cavity;

the static iron core is at least partially positioned in the accommodating cavity and fixedly connected with the shell; and

the movable iron core assembly, the movable iron core assembly sets up hold the intracavity, the movable iron core assembly includes:

the movable iron core is positioned at one side of the static iron core and is provided with a cavity, a reset spring is arranged between the movable iron core and the static iron core, and the reset spring pushes the movable iron core towards a direction away from the static iron core;

a valve needle comprising a first valve needle portion and a second valve needle portion, the first valve needle portion being located within the cavity and the second valve needle portion being located at least partially outside the cavity; and

the elastic piece is arranged in the cavity, two ends of the elastic piece are respectively abutted against the first valve needle part and the movable iron core, and the elastic piece pushes the first valve needle part towards a direction away from the static iron core;

wherein the plunger assembly is configured to be driven by a drive assembly between a closed position in which the second needle portion closes the second passage and an open position in which the second needle portion opens the second passage and the second passage communicates with the cavity.

Optionally, a first noise reduction pad is arranged between the static iron core and the movable iron core; the first noise reduction pad is compressed when the plunger assembly is in the open position.

Optionally, the movable iron core is provided with a noise reduction pad hole, and the first noise reduction pad is located in the noise reduction pad hole and at least partially protrudes out of the surface of the movable iron core.

Optionally, the height of the first noise reduction pad protruding out of the surface of the movable iron core is 0.05 mm-0.1 mm.

Optionally, the elastic component is buffer spring, first needle portion is equipped with the reference column, buffer spring cover establish to the reference column, buffer spring's one end butt to move the iron core back towards quiet iron core's intracavity surface, buffer spring's the other end butt to first needle portion.

Optionally, the first valve needle portion is provided with a radially protruding stop collar, the size of the cavity matches the size of the stop collar, and the other end of the buffer spring abuts against the stop collar.

Optionally, the movable iron core is further formed with an avoidance groove, and the position of the avoidance groove corresponds to the position of the positioning column in the moving direction of the movable iron core assembly.

Optionally, the size of the positioning column is matched with the size of the avoidance groove, and the end part of the positioning column is positioned in the avoidance groove and is configured to move along the inner wall of the avoidance groove.

Optionally, a second noise reduction pad is arranged in the avoidance groove, and the second noise reduction pad is at least connected to the bottom of the avoidance groove.

Optionally, the buffer spring and the return spring satisfy:

F ₁ /m ₁ <F ₂ /m ₂ ；

wherein F is ₁ For the elastic force of the return spring when the movable iron core component is positioned at the opening position, m ₁ The mass of the movable iron core component; f (F) ₂ To buffer the elasticity of the spring, m ₂ Is the mass of the valve needle.

Optionally, the movable iron core is formed with a limiting groove, and the one end of the buffer spring is located in the limiting groove.

Optionally, the buffer spring is coaxially disposed with the return spring.

Optionally, a mounting groove for accommodating the return spring is formed in the static iron core, one end of the return spring is abutted to the groove bottom of the mounting groove, and the other end of the return spring at least partially extends out of the notch of the mounting groove and is abutted to the movable iron core.

Optionally, the driving assembly includes a coil, and the coil is sleeved outside the housing.

Optionally, the movable iron core includes:

the first movable iron core is arranged close to the static iron core, the reset spring is positioned between the first movable iron core and the static iron core, and the elastic piece is positioned between the first valve needle part and the first movable iron core; and

the second movable iron core is detachably connected to the first movable iron core and is provided with the cavity, and a through hole allowing the second valve needle part to pass through is formed in one side of the second movable iron core away from the first movable iron core.

The utility model provides a normally closed electromagnetic valve, after being electrified, a movable iron core component moves towards a static iron core along the inner wall of a sleeve by overcoming the elastic force of a reset spring under the drive of a driving component and is attached together, and at the moment, the reset spring can play a role in buffering and noise reduction. After the outage, move the iron core subassembly and resume the normal position under reset spring's elastic force effect, move the valve needle of iron core subassembly and remove to the direction of keeping away from quiet iron core, until second needle portion shutoff second passageway, at this moment, connect the elastic component between first iron core and first needle portion and can play the effect of buffering and making an uproar falls, the collision between buffering valve needle and the casing. According to the normally closed electromagnetic valve, collision noise in the opening position and the closing position is effectively reduced through the return spring and the elastic piece.

Drawings

The following drawings of embodiments of the present utility model are included as part of the utility model. Embodiments of the present utility model and their description are shown in the drawings to explain the principles of the utility model. In the drawings of which there are shown,

fig. 1 is a schematic structural view of a normally closed solenoid valve according to a preferred embodiment of the present utility model;

FIG. 2 is a schematic cross-sectional view taken along line A-A of FIG. 1, wherein the valve needle closes the second passageway;

FIG. 3 is an exploded view of the normally closed solenoid valve of FIG. 1;

fig. 4 is a schematic cross-sectional structure of a moving core assembly according to a preferred embodiment of the present utility model;

FIG. 5 is a schematic perspective exploded view of the plunger assembly of FIG. 4;

fig. 6 and 7 are schematic cross-sectional views of two other moving core assemblies, respectively;

fig. 8 is a schematic perspective view of the normally closed solenoid valve according to fig. 1, in which only a stationary core, a sleeve, and a return spring are shown;

FIG. 9 is a schematic cross-sectional view of a first plunger of the normally closed solenoid valve of FIG. 1;

FIG. 10 is a schematic cross-sectional view of the normally closed solenoid valve of FIG. 1 in a closed position, showing the coil; and

fig. 11 is a schematic sectional view of the normally closed solenoid valve in fig. 1 in an open position.

Reference numerals illustrate:

100: normally closed solenoid valve 110: shell body

111: valve body 111A: a first channel

112: valve seat 112A: second channel

113: sleeve 120: static iron core

121: mounting groove 130: movable iron core

131: first movable iron core 132: second movable iron core

133: cavity 134: noise reduction pad hole

135: dodge groove 136: limiting groove

140: valve needle 141: first valve needle part

141A: positioning column 141B: limiting ring

142: second needle portion 142A: steel ball

151: return spring 152: elastic piece

153: first noise reduction pad 160: coil

Detailed Description

In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present utility model. It will be apparent, however, to one skilled in the art that embodiments of the utility model may be practiced without one or more of these details. In other instances, well-known features have not been described in detail in order to avoid obscuring the embodiments of the utility model.

In the following description, a detailed structure will be presented for a thorough understanding of embodiments of the present utility model. It will be apparent that embodiments of the utility model may be practiced without limitation to the specific details that are set forth by those skilled in the art. The preferred embodiments of the present utility model are described in detail below, however, the present utility model may have other embodiments in addition to the detailed description, and should not be construed as limited to the embodiments set forth herein.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model, as the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," and/or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The terms "upper", "lower", "front", "rear", "left", "right" and the like are used herein for illustrative purposes only and are not limiting.

Ordinal numbers such as "first" and "second" cited in the present utility model are merely identifiers and do not have any other meaning, such as a particular order or the like. Also, for example, the term "first component" does not itself connote the presence of "second component" and the term "second component" does not itself connote the presence of "first component".

Hereinafter, specific embodiments of the present utility model will be described in more detail with reference to the accompanying drawings, which illustrate representative embodiments of the present utility model and not limit the present utility model.

As described in fig. 1 to 5, for a normally closed solenoid valve 100 of the present utility model, the normally closed solenoid valve 100 includes a housing 110, a stationary core 120, and a movable core assembly.

The housing 110 is formed with a cavity. The housing 110 also has a first passage 111A and a second passage 112A, the first passage 111A communicating with the chamber. The stationary core 120 is at least partially located within the cavity and is fixedly connected to the housing 110.

The movable iron core component is arranged in the accommodating cavity. The plunger assembly includes a plunger 130, a valve needle 140, and an elastic member 152. The movable iron core 130 is located at one side of the stationary iron core 120 and is formed with a cavity 133, a return spring 151 is provided between the movable iron core 130 and the stationary iron core 120, and the return spring 151 pushes against the movable iron core 130 in a direction away from the stationary iron core 120.

The valve needle 140 includes a first valve needle portion 141 and a second valve needle portion 142, the first valve needle portion 141 being located within the cavity 133 and the second valve needle portion 142 being located at least partially outside the cavity 133. The elastic member 152 is disposed in the cavity 133, and both ends of the elastic member 152 are respectively abutted against the first needle portion 141 and the movable core 130, and the elastic member 152 is pushed against the first needle portion 141 in a direction away from the stationary core 120.

The plunger assembly is configured to be movable between a closed position and an open position under the drive of the drive assembly. In the closed position, the second valve needle portion 142 closes the second passage 112A, and in the open position, the second valve needle portion 142 opens the second passage 112A, at which time the second passage 112A communicates with the chamber.

In the present embodiment, the housing 110 includes a valve body 111, a valve seat 112, and a sleeve 113. Specifically, referring to fig. 1 to 5, the valve body 111 is constructed in a hollow structure. Specifically, a sleeve 113 is provided above the valve body 111, and the sleeve 113 is connected to the valve body 111 and configured with a cavity. The other side of the sleeve 113 is connected with a stationary core 120. The plunger assembly is positioned within the cavity and above the valve seat 112.

The valve body 111 is formed with a first passage 111A communicating the inside and outside of the valve body 111 (the first passage 111A communicates with the chamber). A valve seat 112 is provided into the valve body 111, the valve seat 112 being formed with a second passage 112A. Specifically, the second passage 112A has a valve port that can communicate with the chamber.

Referring to fig. 2, the movable core assembly is located between the stationary core 120, the sleeve 113 and the valve seat 112, and is integrally movable along the inner wall of the sleeve 113 by the driving of the driving assembly. The driving component may be a coil 160, where the coil 160 is wound outside the housing 110, and the magnetic force generated by the static iron core 120 will attract the moving iron core component after the static iron core 120 is electrified. In other words, the movable core assembly can move toward the stationary core 120 along the inner wall of the sleeve 113 by the magnetic force.

Referring to fig. 3 to 5, in the present embodiment, the plunger assembly specifically includes a first plunger 131, a second plunger 132, a needle 140, and an elastic member 152.

Wherein the first movable core 131 and the second movable core 132 are detachably connected and formed with a cavity 133, and the elastic member 152 and the needle 140 are located in the cavity 133. The first movable core 131 is located on a side close to the stationary core 120, and the second movable core 132 is provided with a through hole allowing the second needle portion 142 to pass through on a side away from the first movable core 131. Both ends of the elastic member 152 abut against the first needle portion 141 and the first plunger 131, respectively. It will be appreciated that designing the plunger 130 as a split structure facilitates production and assembly.

The return spring 151 is disposed between the first movable core 131 and the stationary core 120. When the normally closed electromagnetic valve 100 of the present utility model is energized, the movable iron core assembly moves toward the stationary iron core 120 under the action of electromagnetic force until the first movable iron core 131 contacts the stationary iron core 120 (at this time, the second valve needle portion 142 of the valve needle 140 is away from the valve seat 112, and the second passage 112A is opened and is in communication with the first passage 111A and the cavity). In this process, the movable iron core assembly presses the return spring 151 to compressively deform the return spring 151, in other words, the movable iron core assembly moves along the inner wall of the sleeve 113 against the elastic force of the return spring 151 under the action of electromagnetic force until abutting against the stationary iron core 120 (see fig. 11). The return spring 151 can well cushion the collision between the moving core assembly (first moving core 131) and the stationary core 120 after the energization, thereby reducing the collision noise when the normally closed electromagnetic valve 100 is opened.

When the normally closed solenoid valve 100 of the present utility model is powered off, the movable core assembly moves away from the stationary core 120 by the elastic force of the return spring 151 until the second needle portion 142 of the needle 140 abuts the valve seat 112 and closes the second passage 112A (see fig. 10). When the plunger assembly moves along the inner wall of the sleeve 113 under the action of the elastic force of the return spring 151, since the elastic member 152 (not rigidly connected) is disposed between the valve needle 140 and the first plunger 131, the elastic member 152 can well buffer the contact collision between the second valve needle 142 and the valve seat 112, and reduce the collision noise when the normally closed electromagnetic valve 100 is closed. Specifically, the elastic member 152 can absorb the kinetic energy of the moving core assembly when the valve needle 140 is driven to descend, so as to effectively reduce and reduce the noise of the second valve needle 142 striking the valve seat 112.

Referring to fig. 1, 2 and 8, in the present embodiment, a mounting groove 121 accommodating a return spring 151 is provided in a stationary core 120, one end of the return spring 151 abuts against a groove bottom of the mounting groove 121, and the other end of the return spring 151 at least partially protrudes from a notch of the mounting groove 121.

Preferably, in order to further improve the noise reduction performance of the normally closed solenoid valve 100 of the present utility model and reduce the collision noise between the first movable core 131 and the stationary core 120, a first noise reduction pad 153 is provided between the stationary core 120 and the first movable core 131. The first noise reduction pad 153 is compressed when the plunger assembly is in the open position. The first noise reduction pad 153 reduces noise of the moving iron assembly striking the stationary core 120, and can reduce noise conduction to thereby reduce noise.

Referring to fig. 2 to 5 and 11, when the normally closed solenoid valve 100 is energized to be opened, the movable iron core assembly moves from the closed position to the open position, and the first movable iron core 131 is pressed against the first noise reduction pad 153 between the stationary iron core 120 and the first movable iron core 131 during the movement of the first movable iron core 131 to abut against the stationary iron core 120. The first noise reduction pad 153 and the return spring 151 cooperate to reduce collision noise of the stationary core 120 and the first movable core 131.

The first noise reduction pad 153 may be disposed at the lower end of the stationary core 120 or may be disposed at the top end of the first movable core 131. In the present embodiment, the first noise reduction pad 153 is embedded in the first movable core 131. Referring to fig. 5 and 9, the top of the first movable core 131 is provided with a noise reduction pad hole 134, the first noise reduction pad 153 is positioned in the noise reduction pad hole 134, and the first noise reduction pad 153 is at least partially protruded from the top surface of the first movable core 131 to play a role in noise reduction.

Preferably, the height of the first noise reduction pad 153 protruding from the top surface of the first movable core 131 is 0.05mm to 0.1mm. Thus, electromagnetic force between the static iron core 120 and the first movable iron core 131 is not affected, a certain gap between the static iron core 120 and the first movable iron core 131 can be ensured, and direct collision between the static iron core 120 and the first movable iron core 131 is avoided. The material of the first noise reduction pad 153 may be rubber, plastic, or sound absorbing cotton.

Preferably, in the present embodiment, the elastic member 152 is a buffer spring 152. One end of the buffer spring 152 abuts against the cavity inner surface of the first movable core 131 facing away from the stationary core 120, and the other end of the buffer spring 152 abuts against the first needle portion 141. Specifically, the first needle portion 141 is provided with a positioning column 141A, and the buffer spring 152 is sleeved to the positioning column 141A. It will be appreciated that the buffer spring 152 in the cavity 133 is in a pre-compressed state, and the elastic force of the buffer spring 152 can keep the valve needle 140 tightly against the second plunger 132. Referring to fig. 2, 10 and 11, in the present embodiment, the buffer spring 152 is sleeved outside the positioning column 141A and is disposed coaxially with the return spring 151.

In other embodiments not shown in the present utility model, the elastic member 152 may be a rubber member, for example, the elastic member 152 may be a rubber tube sleeved outside the positioning post 141A. The elastic member 152 may be a rubber column abutting between the first plunger 131 and the first needle portion 141.

Referring to fig. 2 and 5, the first needle portion 141 is provided with a radially protruding stopper ring 141B, and the other end of the buffer spring 152 abuts against the stopper ring 141B. Preferably, the dimensions of the cavity 133 and the stop collar 141B match. By "size matching" is specifically meant that the inner diameter of the cavity 133 is slightly larger than the outer diameter of the stop collar 141B, e.g., the inner diameter of the cavity 133 may be 103% -110% of the outer diameter of the stop collar 141B. The size of the limit ring 141B is matched with the size of the cavity 133, so that the shaking degree of the valve needle 140 relative to the cavity 133 in the moving process can be reduced, and the valve needle 140 can move stably in the cavity 133. The retainer ring 141B also retains the first needle portion 141 within the cavity 133 without being dislodged from the second plunger 132.

Preferably, in the present embodiment, the buffer spring 152 and the return spring 151 satisfy:

F ₁ /m ₁ <F ₂ /m ₂ ；

wherein F is ₁ To the elasticity of the return spring 151 at the time of power failure, m ₁ The mass of the movable iron core component; f (F) ₂ To buffer the spring force of the spring 152 when power is off, m ₂ Is the mass of the valve needle 140.

In other words, the acceleration of the movable core assembly is smaller than the acceleration of the valve needle 140, so as to avoid the valve needle 140 moving along the cavity 133 toward the stationary core 120 relative to the movable core 130 when the movable core assembly moves away from the stationary core 120, so as to ensure that the valve needle 140 can move away from the stationary core 120 when power is off, and ensure that the second valve needle portion 142 can block the second channel 112A (with good sealing performance).

Referring to fig. 2-5, in one embodiment of the present utility model, the second needle portion 142 of the needle 140 further includes a terminal steel ball 142A, the steel ball 142A having a size greater than the size of the second passage 112A. The coil 160 is disposed outside the sleeve 113 (see fig. 10 and 11), and after the coil 160 is energized, the stationary core 120 attracts the movable core assembly to move upward, the steel ball 142A moves upward with it, and the second passage 112A is opened; after the coil 160 is powered off, the second valve needle portion 142 moves away from the static iron core 120 under the action of the elastic member 152, and the steel ball 142A is connected to the second channel 112A in a sealing manner.

Referring to fig. 4, the first plunger 131 is formed with a limiting groove 136, and one end of the buffer spring 152 is located in the limiting groove 136. The stopper groove 136 can restrict the movement of the buffer spring 152.

Preferably, the movable core 130 is further formed with a dodging groove 135, and the position of the dodging groove 135 corresponds to the position of the positioning post 141A in the moving direction of the movable core assembly. Referring to fig. 6 and 7, in other embodiments of the utility model, the second valve needle portion 142 is contoured to match the dimensions of the second passage 112A, and the second passage 112A may be directly sealed by the cooperation of the second valve needle portion 142 with the second passage 112A.

Referring to the embodiment shown in fig. 6, the first movable core 131 is formed with a relief groove 135 at the bottom thereof, and the positioning post 141A has a size matching that of the relief groove 135. The end of the positioning post 141A is positioned within the escape groove 135 and is configured to move along the inner wall of the escape groove 135. The valve needle 140 can move stably with respect to the second plunger 132 when the power is off.

Referring to the embodiment shown in fig. 7, the positioning post 141A may not be located in the avoidance groove 135, so that the overall volume of the normally closed electromagnetic valve 100 may be reduced to some extent.

Preferably, the bottom of the avoiding groove 135 can be provided with a noise-reducing cotton, a rubber pad and the like to better realize buffering and noise reduction.

Preferably, a second noise reduction pad may be provided at the bottom of the avoidance groove 135. The collision between the positioning column 141A and the first movable iron core 131 is buffered.

Referring to fig. 10 and 11, the normally closed solenoid valve 100 of the present utility model operates as follows:

when the coil 160 is not energized, a gap is formed between the movable core assembly and the stationary core 120, the buffer spring 152 pushes the first needle portion 141 in a direction away from the stationary core 120, and the second needle portion 142 closes the second passage 112A, and at this time, the second passage 112A is not communicated with the first passage 111A, and the solenoid valve is closed.

After the coil 160 is energized, the movable core assembly moves toward the stationary core 120 under the action of magnetic force until the first movable core 131 contacts the stationary core 120 (without a gap) and compresses the return spring 151, the second valve needle portion 142 moves toward the stationary core 120 to open the second passage 112A, a gap is provided between the second valve needle portion 142 and the second passage 112A, the second passage 112A communicates with the first passage 111A, and the solenoid valve is in an open state.

When the coil 160 is switched from energized to de-energized, the magnetic force that attracts the movable core assembly disappears, the movable core assembly moves away from the stationary core 120 under the action of the elastic member 152 of the return spring 151, the second needle portion 142 closes the second passage 112A, the communication state between the first passage 111A and the second passage 112A is cut off, and the solenoid valve is in a closed state.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model pertains. The terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting of the utility model. Terms such as "disposed" or the like as used herein may refer to either one element being directly attached to another element or one element being attached to another element through an intermediate member. Features described herein in one embodiment may be applied to another embodiment alone or in combination with other features unless the features are not applicable or otherwise indicated in the other embodiment.

The present utility model has been described in terms of the above embodiments, but it should be understood that the above embodiments are for purposes of illustration and description only and are not intended to limit the utility model to the embodiments described. Those skilled in the art will appreciate that many variations and modifications are possible in light of the teachings of the utility model, which variations and modifications are within the scope of the utility model as claimed.

Claims (15)

1. A normally closed solenoid valve, characterized in that the normally closed solenoid valve comprises:

the shell is provided with a containing cavity and a first channel and a second channel, and the first channel is communicated with the containing cavity;

the static iron core is at least partially positioned in the accommodating cavity and fixedly connected with the shell; and

the movable iron core assembly, the movable iron core assembly sets up hold the intracavity, the movable iron core assembly includes:

the movable iron core is positioned at one side of the static iron core and is provided with a cavity, a reset spring is arranged between the movable iron core and the static iron core, and the reset spring pushes the movable iron core towards a direction away from the static iron core;

a valve needle comprising a first valve needle portion and a second valve needle portion, the first valve needle portion being located within the cavity and the second valve needle portion being located at least partially outside the cavity; and

the elastic piece is arranged in the cavity, two ends of the elastic piece are respectively abutted against the first valve needle part and the movable iron core, and the elastic piece pushes the first valve needle part towards a direction away from the static iron core;

wherein the plunger assembly is configured to be driven by a drive assembly between a closed position in which the second needle portion closes the second passage and an open position in which the second needle portion opens the second passage and the second passage communicates with the cavity.

2. The normally closed solenoid valve according to claim 1, wherein a first noise reduction pad is provided between the stationary core and the movable core; the first noise reduction pad is compressed when the plunger assembly is in the open position.

3. The normally closed solenoid valve according to claim 2, wherein the plunger is provided with a noise reduction pad hole, and the first noise reduction pad is located in the noise reduction pad hole and protrudes at least partially from a surface of the plunger.

4. The normally closed electromagnetic valve according to claim 3, wherein the height of the first noise reduction pad protruding from the surface of the movable iron core is 0.05mm to 0.1mm.

5. The normally closed electromagnetic valve according to any one of claims 1 to 4, wherein the elastic member is a buffer spring, the first valve needle portion is provided with a positioning post, the buffer spring is sleeved to the positioning post, one end of the buffer spring is abutted to the cavity inner surface of the movable iron core, which is opposite to the static iron core, and the other end of the buffer spring is abutted to the first valve needle portion.

6. The normally closed solenoid valve according to claim 5, wherein the first needle portion is provided with a radially projecting check ring, the size of the cavity and the size of the check ring match, and the other end of the buffer spring abuts against the check ring.

7. The normally closed solenoid valve according to claim 5, wherein the plunger is further formed with a relief groove whose position corresponds to the position of the positioning post in the moving direction of the plunger assembly.

8. The normally closed solenoid valve of claim 7, wherein the positioning post is sized to match the size of the bypass slot, and wherein an end of the positioning post is positioned within the bypass slot and is configured to move along an inner wall of the bypass slot.

9. The normally closed solenoid valve according to claim 7, wherein a second noise reduction pad is provided in the escape groove, and the second noise reduction pad is connected to at least a groove bottom of the escape groove.

10. The normally closed solenoid valve according to claim 5, wherein the cushion spring and the return spring satisfy:

F ₁ /m ₁ <F ₂ /m ₂ ；

wherein F is ₁ For the elastic force of the return spring when the movable iron core component is positioned at the opening position, m ₁ The mass of the movable iron core component; f (F) ₂ To buffer the elasticity of the spring, m ₂ Is the mass of the valve needle.

11. The normally closed solenoid valve according to claim 5, wherein the plunger is formed with a limit groove, and the one end of the buffer spring is located in the limit groove.

12. The normally closed solenoid valve according to claim 5, wherein the buffer spring is provided coaxially with the return spring.

13. The normally closed electromagnetic valve according to any one of claims 1 to 4, characterized in that a mounting groove that accommodates the return spring is provided in the stationary core, one end of the return spring is abutted to a groove bottom of the mounting groove, and the other end of the return spring is at least partially projected from a notch of the mounting groove and is abutted to the movable core.

14. The normally closed solenoid valve according to any one of claims 1 to 4, wherein the drive assembly includes a coil that is sleeved outside the housing.

15. The normally closed electromagnetic valve according to any one of claims 1 to 4, characterized in that the plunger includes:

the first movable iron core is arranged close to the static iron core, the reset spring is positioned between the first movable iron core and the static iron core, and the elastic piece is positioned between the first valve needle part and the first movable iron core; and

the second movable iron core is detachably connected to the first movable iron core and is provided with the cavity, and a through hole allowing the second valve needle part to pass through is formed in one side of the second movable iron core away from the first movable iron core.

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