CN215738922U

CN215738922U - Electromagnetic valve and sphygmomanometer comprising same

Info

Publication number: CN215738922U
Application number: CN202121122354.5U
Authority: CN
Inventors: 江沛杰; 李辉; 赵仲康
Original assignee: Shenzhen Sangtaida Technology Co ltd
Current assignee: Shenzhen Sangtaida Technology Co ltd
Priority date: 2021-05-22
Filing date: 2021-05-22
Publication date: 2022-02-08
Anticipated expiration: 2031-05-22

Abstract

The application relates to the field of fluid conveying control, in particular to an electromagnetic valve and a sphygmomanometer comprising the same, wherein the electromagnetic valve comprises a shell and a framework, and the framework is arranged in the shell; run through on the skeleton and be provided with the hole of sliding, it crosses gas spare and opens and close the inner core to be provided with in the hole of sliding, open and close the cooperation of sliding of inner core and hole of sliding, it helps the piece to be provided with elasticity between the pore wall of opening and close inner core and hole of sliding, elasticity is right the piece and is had the portion that resets of ventilating steady portion and elasticity, the portion that resets of elasticity has the elastic force that will open and close the one side promotion that the inner core orientation was kept away from gas spare place, the skeleton that has the magnetic induction coil around has the drive and opens and close the magnetic force that the inner core orientation was close to the one side motion that gas spare was located, magnetic force is greater than the elastic force. The hole wall that the steady portion of ventilating and open and close inner core and slip hole all butts to make the inner wall of opening and close inner core and slip hole can not lead to collision each other because the air current velocity of flow is too fast, thereby improved the noise problem after the solenoid valve is opened.

Description

Electromagnetic valve and sphygmomanometer comprising same

Technical Field

The present application relates to the field of fluid delivery control, and in particular, to a solenoid valve and a sphygmomanometer comprising the same.

Background

The electromagnetic valve is an automatic basic element for realizing control by utilizing an electromagnetic induction principle, can be matched with different circuits to realize expected control, and has the advantages of high control precision, flexible use scene and the like. Solenoid valves can be broadly divided into three broad categories according to their control principle: direct-acting solenoid valves, step-by-step direct-acting solenoid valves, and pilot solenoid valves. Due to the simple structure, the direct-acting electromagnetic valve is often used in a plurality of application scenes with compact structure. The general principle of the direct-acting solenoid valve can be explained as that when an electromagnetic coil inside the direct-acting solenoid valve is electrified, the electromagnetic coil generates a magnetic field due to the electromagnetic induction principle, and the magnetic field controls an opening and closing inner core to correspondingly move, so that a valve inside the solenoid valve is correspondingly opened or closed.

In the related art, a sphygmomanometer is provided which uses a direct-acting solenoid valve as a control switch for controlling gas discharge in the sphygmomanometer. As shown in the attached figure 1, the electromagnetic valve comprises a valve body shell 1 ', a framework 2' and an end cover 3 ', wherein the framework 2' is arranged in the valve body shell 1 ', and the end cover 3' is positioned in the valve body shell 1 'and is fixedly connected with the valve body shell 1' and limits and fixes the framework 2 'in the valve body shell 1'; the framework 2 ' comprises a wound magnetic induction coil 21 ', a sliding hole 22 ' is formed in the framework 2 ', an opening and closing inner core 23 ', an air passing piece 24 ' and an elastic piece 25 ' are arranged in the sliding hole 22 ', the opening and closing inner core 23 ' is in sliding fit with the sliding hole 22 ', the air passing piece 24 ' is located at the bottom of the framework 2 ' and is fixedly connected with the valve body shell 1 ', the elastic piece 25 ' is arranged between the air passing piece 24 ' and the opening and closing inner core 23 ', and the elastic piece 25 ' has elastic force for pushing the opening and closing inner core 23 ' towards one side far away from the position where the air passing piece 24 ' is located.

After the electromagnetic valve is powered on and started, the induction coil on the framework 2 ' overcomes the elastic force of the elastic piece 25 ' through the electromagnetic induction principle, and pushes the opening and closing inner core 23 ' towards one side where the air passing piece 24 ' is located, so that the opening and closing inner core 23 ' completely covers and seals the air inlet 241 ' on the air passing piece 24 ', and the closing function of the electromagnetic valve is realized; when the electromagnetic valve is switched off, the magnetic driving force of the electromagnetic coil disappears, the elastic element 25 'pushes the opening and closing inner core 23' towards the side away from the air passing element 24 ', so that the air inlet hole 241' is communicated with the sliding hole 22 ', and the air in the sphygmomanometer is discharged from the upper end of the sliding hole 22' through the air inlet hole 241 'of the air passing element 24'.

Aiming at the related technology, in order to enable the sealing element for opening and closing the inner core to be stably pressed on the air passing element without shaking, the gap between the opening and closing inner core and the sliding hole needs to be set to be very small, and the common single-side gap is about 0.1 mm. When the electromagnetic valve is opened, the gas flowing into the sliding hole from the gas inlet of the gas passing part moves along the gap between the opening and closing inner core and the sliding hole, and is finally discharged from the upper end of the sliding hole. The flow of the exhaust gas in the sphygmomanometer is generally larger, and the gas with larger flow is concentrated in a smaller gap between the opening and closing inner core and the sliding hole, so that the flow velocity of the gas in the gap is easily increased suddenly, the air is rubbed with each other and generates vibration, the hole walls of the opening and closing inner core and the sliding hole are collided with each other due to the vibration of the air, and the noise is greatly generated.

SUMMERY OF THE UTILITY MODEL

In order to improve the noise problem of solenoid valve exhaust process among the sphygmomanometer, this application provides a solenoid valve and contains sphygmomanometer of this solenoid valve.

The application provides a solenoid valve and contain sphygmomanometer of this solenoid valve adopts following technical scheme:

in a first aspect, the present application provides an electromagnetic valve, which adopts the following technical scheme:

a solenoid valve comprises a shell and a framework, wherein the shell is provided with a valve cavity, a magnetic induction coil is wound on the framework, and the framework is arranged in the valve cavity;

the framework is provided with a sliding hole, an air passing part and an opening and closing inner core are arranged in the sliding hole, the air passing part is fixed on the shell, one end of the air passing part penetrates out of the sliding hole, the opening and closing inner core is in sliding fit with the sliding hole, an elastic righting part is arranged between the opening and closing inner core and the hole wall of the sliding hole, the elastic righting part is provided with an air-permeable stabilizing part and an elastic resetting part, the air-permeable stabilizing part is abutted to the outer wall of the opening and closing inner core, and the air-permeable stabilizing part is abutted to the hole wall of the sliding hole;

the elastic reset part has elastic force for pushing the opening and closing inner core away from the air passing piece, the framework has magnetic force for driving the opening and closing inner core to move towards one side close to the air passing piece, and the magnetic force is greater than the elastic force;

an air inlet hole for air to pass through is arranged in the air passing piece in a penetrating mode, and when the opening and closing inner core is abutted against the air passing piece, the opening and closing inner core closes the air inlet hole and is close to the opening end face of one side, where the opening and closing inner core is located, of the opening end face.

By adopting the technical scheme, when the electromagnetic valve is not electrified, the elastic resetting part of the elastic righting piece pushes the opening and closing inner core towards one side away from the air passing piece, so that the air inlet hole in the air passing piece is in an open state; when the electromagnetic valve is powered on and started, the magnetic induction coil wound on the framework generates a magnetic field through the electromagnetic induction principle, so that the opening and closing inner core generates a magnetic force moving towards one side where the air passing piece is located, and the magnetic force is greater than the elastic force generated by the elastic reset part on the opening and closing inner core, so that the opening and closing inner core moves towards the air passing piece and seals the air inlet of the air passing piece, and the air inlet is in a closed state. When needs are discharged gas from the piece of crossing gas, cut off the power supply with this solenoid valve, the inlet port changes the open mode from the closed condition, it is gaseous along the inlet port of crossing gas in entering into the slide opening, owing to be provided with the stabilizer of ventilating between the pore wall of opening and close inner core and slide opening, the stabilizer of ventilating can be with the gaseous derivation slide opening in the slide opening in, the stabilizer of ventilating with open and close the equal butt of pore wall of inner core and slide opening, so that the inner wall of opening and close inner core and slide opening can not lead to collision each other because the air current velocity of flow is too fast, thereby the noise problem after the solenoid valve is opened has been improved.

Optionally, the elastic centering member is a spring, and the ventilation stabilizing portion is arranged on the outer peripheral surface of the opening and closing inner core.

Through adopting above-mentioned technical scheme, the spring has simple structure, the production precision is high, simple to operate's advantage, the stabilizer of ventilating with open and close the equal butt of pore wall in inner core and slip hole, the stabilizer of ventilating can form a spiral air flue between the pore wall of opening and close inner core and slip hole, can improve the turbulent phenomenon of air in carminative simultaneously to alleviate the looks mutual friction between the air, further improve the noise problem after the solenoid valve is opened.

Optionally, an installation ring groove is formed in the outer peripheral surface of one end, close to the opening and closing inner core, of the air passing piece, and the elastic reset part is arranged in the installation ring groove of the air passing piece; open and close the inner core and keep away from one side at air passing piece place and be provided with spacing boss, the one end at air passing piece place and spacing boss butt are kept away from to the steady part of ventilating, and the elasticity resets one side at air passing piece place and the steady part butt of ventilating are kept away from.

Through adopting above-mentioned technical scheme, with elasticity reset portion with open and close the in-process that the inner core installed the hole that slides, because elasticity reset portion sets up in the installation annular of crossing gas piece outer peripheral face, and elasticity reset portion is close to one end and the shell butt of crossing gas piece. Compare in crossing the gas piece with elasticity reset portion and opening and close between the inner core, at the installation, at first need will open and close the inner core and install to slide downtheholely, again with elasticity reset portion install open and close on the inner core, install skeleton and shell again so that cross the gas piece and support elasticity reset portion, elasticity reset portion appears crooked dislocation easily and leads to the emergence of abnormal sound between crossing the gas piece and opening and close the inner core. And in this technical scheme, can install earlier the stabilization part of ventilating on opening and close the inner core and with spacing boss butt, install the two together the sliding hole of skeleton again, then install elasticity portion of resetting on the installation annular of crossing gas spare, install skeleton and shell again so that elasticity portion of resetting supports the stabilization part of ventilating, because elasticity portion of resetting is installed earlier in the installation annular of crossing gas spare, thereby improved elasticity portion of resetting and appeared the problem of crooked dislocation between gas spare and opening and close the inner core easily.

Optionally, the pitch diameter of the elastic restoring portion is equal to the pitch diameter of the ventilation stabilizing portion.

Through adopting above-mentioned technical scheme, because the pitch diameter of elasticity portion of resetting equals the pitch diameter of the stabilizer of ventilating, so the position distribution that elasticity portion of resetting and the stabilizer of ventilating butt each other is more even, and elasticity portion of resetting can be more stable with the in-process of the stabilizer of ventilating butt each other.

Optionally, the elastic reset portion and the ventilation stabilizing portion have an abutting position, and the abutting position is located on the outer peripheral side of the opening and closing inner core.

Through adopting above-mentioned technical scheme, the butt position is located the periphery side of opening and close the inner core, and the elasticity portion of resetting is with the in-process of ventilating the mutual butt of stabilizing part, and the outer peripheral face of opening and close the inner core and the pore wall in hole of sliding can play spacing effect to elasticity portion of resetting and the stabilizing part of ventilating, has improved elasticity portion of resetting and the problem that the stabilizing part of ventilating takes place the butt dislocation easily because pressure is too big.

Optionally, an exhaust groove for exhausting air in the sliding hole is formed in the limiting boss.

Through adopting above-mentioned technical scheme, the air discharge duct can provide a more stable air outlet for gas flows out from the hole that slides, improves the problem that the air current gathers between spacing boss and the hole that slides and leads to atmospheric pressure to increase.

Optionally, the exhaust grooves are provided with a plurality of exhaust grooves, and the plurality of exhaust grooves are distributed on the outer peripheral surface of the limiting boss at equal intervals.

Through adopting above-mentioned technical scheme, many air discharge ducts can further increase the effective cross-sectional area of gaseous flow from between spacing boss and the hole that slides, and when gas flow increases, many air discharge ducts can be discharged gas fast to make the exhaust efficiency of this solenoid valve show the promotion.

Optionally, the sealing element is detachably arranged on one side, where the air passing element is located, of the opening and closing inner core, and the opening end face of the air inlet hole can be sealed through the sealing element.

Through adopting above-mentioned technical scheme, use the sealing member to seal the inlet port, after long-time the use, the sealing member can be dismantled and change to make this solenoid valve's sealed maintenance more convenient.

Optionally, the length of the installation part of the ventilation stabilizing part (241) and the opening and closing inner core (23) accounts for 60-80% of the whole length of the opening and closing inner core (23).

By adopting the technical scheme, the length of the ventilating stabilizing part and the mounting part of the opening and closing inner core accounts for 60-80% of the whole length of the opening and closing inner core, so that the mounting of the ventilating stabilizing part and the opening and closing inner core is more stable.

In a second aspect, the present application provides a sphygmomanometer, which adopts the following technical solutions:

a sphygmomanometer comprises the electromagnetic valve.

Through adopting above-mentioned technical scheme, install the sphygmomanometer of this solenoid valve in the use, the whole noise of sphygmomanometer when the gassing process can effectively reduce to exhaust.

In summary, the present application includes at least one of the following beneficial technical effects:

1. when gas in the electromagnetic valve enters the sliding hole from the gas passing piece, the ventilation stabilizing part is arranged between the opening and closing inner core and the hole wall of the sliding hole, so that the gas in the sliding hole can be led out of the sliding hole, and meanwhile, the ventilation stabilizing part is abutted against the opening and closing inner core and the hole wall of the sliding hole, so that the inner walls of the opening and closing inner core and the sliding hole cannot collide with each other due to too high gas flow velocity, and the noise problem after the electromagnetic valve is opened is solved;

2. the ventilation stabilizing part is simple in structure, high in production precision and convenient to install, the ventilation stabilizing part can form a spiral air passage between the opening and closing inner core and the hole wall of the sliding hole when being abutted against the opening and closing inner core and the hole wall of the sliding hole, and air exhausted through the spiral air passage can improve the phenomenon of air turbulence, so that mutual friction between the air is reduced, and the noise problem after the electromagnetic valve is opened is further improved;

3. when the sphygmomanometer provided with the electromagnetic valve is used, the whole noise of the sphygmomanometer during air exhaust can be effectively reduced in the air exhaust process.

Drawings

FIG. 1 is a schematic sectional view of a solenoid valve according to the prior art;

FIG. 2 is a schematic view of the overall structure of a solenoid valve in the embodiment of the present application;

FIG. 3 is an exploded view of a solenoid valve according to an embodiment of the present application;

FIG. 4 is a schematic sectional view of a solenoid valve according to an embodiment of the present application;

FIG. 5 is a top view of the frame of an embodiment of the present application, showing the configuration of the air guide slots and air exit holes.

Description of reference numerals: 1', a valve body shell; 2', a framework; 3', an end cover; 21', a magnetic induction coil; 22', a sliding hole; 23', opening and closing the inner core; 24', a gas passing piece; 25', an elastic reset part; 241', an air inlet hole;

1. a housing; 11. a valve cavity; 2. a framework; 20. a baffle plate; 201. a gas guide groove; 202. an air outlet; 21. a sliding hole; 23. opening and closing the inner core; 231. a limiting boss; 2311. an exhaust groove; 232. a seal member; 24. an elastic righting member; 241. a ventilation stabilizing section; 242. an elastic reset portion; 26. a pin; 3. a gas passing piece; 31. a connecting section; 32. an air intake section; 321. an air inlet; 322. mounting a ring groove; 4. and (4) end covers.

Detailed Description

The present application is described in further detail below with reference to figures 2-5.

The embodiment of the application discloses a solenoid valve. Referring to fig. 2 and 3, the solenoid valve includes a housing 1, a frame 2, a gas passing member 3, and an end cap 4.

Referring to fig. 3 and 4, the housing 1 has a valve cavity 11, the framework 2 is installed in the valve cavity 11, and the end cover 4 is detachably installed in the valve body housing 1 by means of bolt fixing and limits and fixes the framework 2 in the valve body housing 1. Two pins 26 are fixedly mounted on the upper end surface of the framework 2, a magnetic induction coil (not shown in the figure) is wound on the framework 2, and two lead ends of the magnetic induction coil are respectively led out from the upper end of the framework 2 and connected to the corresponding pins 26 to be electrically connected with other control units.

Referring to fig. 3 and 4, an air passing member 3 is installed in the valve cavity 11 of the housing 1, and an air inlet hole 321 which is vertically through is formed in the air passing member 3. The air passing part 3 is roughly arranged in a stepped cylinder shape, the air passing part 3 penetrates out from the bottom of the shell 1, and the air passing part 3 is in interference fit with the shell 1 through the outer peripheral surface so as to be clamped on the shell 1. The air passing part 3 is provided with a connecting section 31 and an air inlet section 32, the connecting section 31 of the air passing part 3 penetrates out of the shell 1 and is used for connecting other exhaust pipelines except the electromagnetic valve, the air inlet section 32 of the air passing part 3 is positioned in the valve cavity 11, and the end face of the air inlet section 32 far away from the connecting section 31 is provided with an installation ring groove 322.

Referring to fig. 4 and 5, a slide hole 21 is provided in the frame 2, and the downward end of the slide hole 21 is open. The upper end of the framework 2 is provided with a baffle plate 20, the baffle plate 20 is provided with an air outlet 202 which penetrates through the baffle plate from top to bottom, one side of the baffle plate 20, which is close to the sliding hole 21, is provided with an air guide groove 201, the air guide groove 201 is arranged in a cross shape, and the air guide groove 201 is communicated with the air outlet 202. It is noted that after the framework 2 is installed in the valve cavity 11 of the housing 1, the air inlet section 32 of the air passing member 3 extends into the sliding hole 21 and is located at the lower part of the sliding hole 21.

Referring to fig. 3 and 4, an opening and closing inner core 23 is arranged in the sliding hole 21, the opening and closing inner core 23 is substantially cylindrical, and the opening and closing inner core 23 is in sliding fit with the sliding hole 21. The opening and closing inner core 23 may be made of a metal material capable of being attracted by the magnet, and in this embodiment, the opening and closing inner core 23 is made of carbon steel. The upper end of the opening and closing inner core 23 is provided with a limit boss 231, and the limit boss 231 is arranged in a cylindrical shape. The outer circumferential surface of the limiting boss 231 is provided with a plurality of exhaust grooves 2311 at equal intervals, and all the exhaust grooves 2311 are vertically arranged downwards. Open and close inner core 23 and cross one side demountable installation at air fitting 3 place and have sealing member 232, and sealing member 232 is the flexible glue material, and sealing member 232 can cover the terminal surface that the inner core 23 place was opened and close to the inlet port 321 orientation totally and seal, uses the back for a long time, and sealing member 232 can be dismantled and change to make this solenoid valve's sealed maintenance more convenient.

Referring to fig. 3 and 4, the outer peripheral surface of the opening and closing inner core 23 is provided with an elastic centering member 24, the elastic centering member 24 has a ventilation stabilizing portion 241 and an elastic resetting portion 242, the ventilation stabilizing portion 241 abuts against the outer wall of the opening and closing inner core 23, and the ventilation stabilizing portion 241 abuts against the hole wall of the sliding hole 21, so that the opening and closing inner core 23 can stably slide in the sliding hole 21 and gas can pass through the opening and closing inner core 23 and the sliding hole 21. The length of the installation part of the ventilation stabilizing part 241 and the opening and closing inner core 23 accounts for 60-80% of the whole length of the opening and closing inner core 23, so that the installation of the ventilation stabilizing part and the opening and closing inner core is more stable.

In this embodiment, the resilient centralizer 24 is provided as a spring.

Referring to fig. 3 and 4, in order to make the solenoid valve in an open state without being powered on, the elastic reset portion 242 is mounted on the mounting ring groove 322 of the air passing piece 3, and the elastic reset portion 242 has an elastic force that pushes the opening and closing inner core 23 toward a side away from the air passing piece 3, so that the sealing member 232 on the opening and closing inner core 23 does not cover and seal the air inlet hole 321, thereby keeping the air inlet hole 321 in a normally open state.

Referring to fig. 4, when the electromagnetic valve is not energized, one end of the ventilation stabilizer 241 abuts against the limiting boss 231 of the opening and closing inner core 23, the other end of the ventilation stabilizer 241 abuts against the mounting ring groove 322 on the air passing piece 3, and the ventilation stabilizer 241 pushes the opening and closing inner core 23 towards the side away from the air passing piece 3, so that the air inlet hole 321 in the air passing piece 3 is in an open state.

Referring to fig. 4, when the solenoid valve is powered on and started, the magnetic induction coil wound on the framework 2 generates a magnetic field according to the electromagnetic induction principle, so as to generate a magnetic attraction force for moving the opening and closing inner core 23 toward the side close to the air passing part 3, and since the magnetic force is greater than the elastic force generated by the elastic reset part 242 for opening and closing the inner core 23, the opening and closing inner core 23 is acted by the magnetic attraction force, moves toward the air passing part 3, seals the air inlet 321 of the air passing part 3, and thus the air inlet 321 is in a closed state.

Referring to fig. 4, when gas needs to be exhausted from the gas passing member 3, the electromagnetic valve is powered off, the magnetic attraction of the magnetic induction coil to the opening and closing inner core 23 disappears, the ventilation stabilizing portion 241 pushes the opening and closing inner core 23 towards the side away from the gas passing member 3, so that the opening and closing inner core 23 is abutted to the bottom surface of the baffle plate 20 of the framework 2, the air inlet 321 is changed from the closed state to the open state, the gas enters the sliding hole 21 along the air inlet 321 of the gas passing member 3, because the ventilation stabilizing portion 241 is arranged between the opening and closing inner core 23 and the hole wall of the sliding hole 21, the ventilation stabilizing portion 241 can form a spiral air passage between the opening and closing inner core 23 and the hole wall of the sliding hole 21 while abutting against the opening and closing inner core 23 and the hole wall of the sliding hole 21, the phenomenon of air turbulence can be improved while exhausting, and the mutual friction between the air can be reduced, thereby improving the noise problem after the electromagnetic valve is opened.

Referring to fig. 3 and 5, the gas in the sliding hole 21 enters the plurality of exhaust grooves 2311 of the limiting boss 231 through the spiral gas passages formed between the opening and closing inner core 23 and the hole wall of the sliding hole 21 by the ventilation stabilizing portion 241, the plurality of exhaust grooves 2311 can increase the effective cross-sectional area of the gas flowing out from between the limiting boss 231 and the sliding hole 21, and when the gas flow is increased, the plurality of exhaust grooves 2311 can rapidly discharge the gas into the gas guide groove 201 of the baffle plate 20 and discharge the gas out of the valve body from the gas outlet 202 through the gas guide groove 201, so that the exhaust efficiency of the solenoid valve is remarkably improved.

The implementation principle of the electromagnetic valve in the embodiment of the application is as follows: the solenoid valve circular telegram starts, and the magnetic induction coil of coiling produces the magnetic field through the electromagnetic induction principle on the skeleton 2, opens and close inner core 23 and receive the effect of magnetic attraction and move towards air passing piece 3 and seal air inlet 321 of air passing piece 3, and air inlet 321 is in the closed condition. The electromagnetic valve is powered off, the magnetic attraction of the magnetic induction coil to the opening and closing inner core 23 disappears, the elastic reset part 242 pushes the opening and closing inner core 23 towards one side far away from the air passing part 3, the air inlet hole 321 is in an open state, air enters the sliding hole 21 along the air inlet hole 321 of the air passing part 3, the air enters the spiral air passage formed by the ventilation stabilizing part 241 between the opening and closing inner core 23 and the hole wall of the sliding hole 21 from the sliding hole 21, the air in the sliding hole 21 enters the plurality of air exhaust grooves 2311 of the limiting boss 231 through the spiral air passage, and is exhausted out of the valve body from the air outlet hole 202 through the air guide groove 201.

The embodiment of the application also discloses a sphygmomanometer, which comprises the electromagnetic valve, and the whole noise of the sphygmomanometer during air exhaust can be effectively reduced in the air exhaust process in the using process of the sphygmomanometer provided with the electromagnetic valve.

The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited thereby. Wherein like parts are designated by like reference numerals. It should be noted that the terms "front," "back," "left," "right," "upper" and "lower" used in the following description refer to directions in the drawings, and the terms "inner" and "outer" refer to directions toward and away from, respectively, the geometric center of a particular component. Therefore, the method comprises the following steps: all equivalent changes made according to the structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The electromagnetic valve is characterized by comprising a shell (1) and a framework (2), wherein the shell (1) is provided with a valve cavity (11), the framework (2) is wound with a magnetic induction coil, and the framework (2) is arranged in the valve cavity (11);

the air-permeable shell structure is characterized in that a sliding hole (21) is formed in the framework (2), an air passing piece (3) and an opening and closing inner core (23) are arranged in the sliding hole (21), the air passing piece (3) is fixed on the shell (1), one end of the air passing piece (3) penetrates out of the sliding hole (21), the opening and closing inner core (23) is in sliding fit with the sliding hole (21), an elastic centering piece (24) is arranged between the opening and closing inner core (23) and the hole wall of the sliding hole (21), the elastic centering piece (24) is provided with an air-permeable stabilizing part (241) and an elastic resetting part (242), the air-permeable stabilizing part (241) is abutted to the outer wall of the opening and closing inner core (23), and the air-permeable stabilizing part (241) is abutted to the hole wall of the sliding hole (21);

the elastic reset part (242) has an elastic force for pushing the opening and closing inner core (23) away from the air passing piece (3), the framework (2) has a magnetic force for driving the opening and closing inner core (23) to move towards one side close to the air passing piece (3), and the magnetic force is greater than the elastic force;

an air inlet hole (321) for air to pass through is arranged in the air passing piece (3) in a penetrating mode, when the opening and closing inner core (23) is abutted against the air passing piece (3), the opening and closing inner core (23) seals the opening end face, close to one side where the opening and closing inner core (23) is located, of the air inlet hole (321).

2. A solenoid valve according to claim 1, characterised in that said elastic centering element (24) is a spring and said vent stabilizer (241) is arranged on the outer peripheral surface of said opening and closing core (23).

3. The electromagnetic valve according to claim 2, characterized in that the outer peripheral surface of the end of the air passing member (3) close to the opening and closing inner core (23) is provided with a mounting ring groove (322), and the elastic reset part (242) is arranged in the mounting ring groove (322) of the air passing member (3); open and close inner core (23) and keep away from cross one side at gas piece (3) place is provided with spacing boss (231), the steady portion of ventilating (241) keep away from cross one end at gas piece (3) place with spacing boss (231) butt, elasticity resets one side (242) keep away from cross gas piece (3) place with the steady portion of ventilating (241) butt.

4. A solenoid valve according to claim 3, characterised in that the pitch diameter of the elastic return portion (242) is equal to the pitch diameter of the venting stabiliser (241).

5. A solenoid valve according to claim 4, characterized in that said elastic return portion (242) and said ventilation stabilizer portion (241) have abutment positions located on the outer peripheral side of said opening and closing core (23).

6. The electromagnetic valve according to claim 4, characterized in that the limit boss (231) is provided with an exhaust groove (2311) for exhausting air in the sliding hole (21).

7. The electromagnetic valve according to claim 6, wherein the exhaust grooves (2311) are provided in plural numbers, and the plural exhaust grooves (2311) are equally spaced on the outer peripheral surface of the stopper projection (231).

8. The electromagnetic valve according to claim 1, characterized in that a sealing element (232) is detachably disposed on a side of the opening and closing inner core (23) facing the air passing element (3), and the sealing element (232) can seal an opening end face of the air inlet hole (321).

9. The electromagnetic valve according to claim 1, characterized in that the length of the vent stabilizer (241) and the mounting portion of the opening and closing inner core (23) is 60-80% of the total length of the opening and closing inner core (23).

10. A sphygmomanometer comprising the electromagnetic valve according to any one of claims 1 to 9.