JPH07233883A - Solenoid valve - Google Patents

Abstract

PURPOSE:To smoothly lead the fluid introduced from an inflow port to an effluence port side, even in the case where the differential pressure between the pressure on the inflow port side and the pressure on an effluence port side is small. CONSTITUTION:A Laval-nozzle shaped part 26 is formed at an effluence port 24 formed on a valve case 22. Accordingly, the fluid which is introduced into the valve case 22 through an inflow 'port 23 passes through the Laval-nozzle- shaped part 26 of the effluence port 24, and led outside the effluence port 24, in the state where the flow speed is accelerated and the negative pressure generated on the effluence port 24 side increases, and the fluid which is led into the valve case 22 from the inflow port 23 can be smoothly led to the effluence port 24 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve which is interposed in a fluid passage or the like and operates so as to connect or disconnect the fluid passage.

[0002]

2. Description of the Related Art Generally, a solenoid valve interposed in a fluid passage or the like opens and closes a fluid passage forming a hydraulic or pneumatic circuit by operating a solenoid actuator to move a valve body to and from a valve seat. It is used for hydraulic circuits, for example, as solenoid valves for opening / closing control of fuel injection valves, fuel hoses, etc., and for pneumatic circuits, for example, as solenoid valves for pilots. And so on.

In an internal combustion engine for automobiles, etc., the evaporated fuel gas (evaporative gas) generated in the fuel tank is temporarily stored in the canister, and the evaporated gas is introduced into the intake passage when the engine is operating. A system that burns inside the body to prevent evaporative emission from being released into the atmosphere (hereinafter referred to as the evaporative purge system)
Has been adopted.

This type of prior art evaporative purge system includes an engine body, a fuel tank, a canister for storing evaporative gas generated in the fuel tank, a conduit for connecting the canister and the fuel tank, and the engine body. The intake manifold and the evaporative purge passage that communicates with the canister are generally configured, and in the middle of the evaporative purge passage, the evaporative purge passage is provided to control the introduction of evaporative gas into the intake manifold according to the operating state of the engine. An electromagnetic valve (evaporative purge control valve) that connects and disconnects is provided.

Such an evaporative purge control valve enters the intake manifold by shutting off the evaporative purge passage midway when the engine throttle valve is fully open (at full throttle) or fully closed (at idle), for example. When the throttle valve is not fully opened or fully closed (the valve opening is an intermediate opening), the evaporation purge passage is connected before and after the evaporation purge control valve.

In this way, when the canister and the intake manifold communicate with each other via the evaporation purge passage and the evaporation purge control valve, the evaporation gas stored in the canister causes the evaporation gas stored in the intake manifold and the inside of the canister to have a negative pressure. Due to the pressure difference from the pressure (atmospheric pressure), it is introduced into the intake manifold through the evaporation purge passage and is supplied to the engine body as a part of fuel.

[0007]

By the way, in the above-mentioned prior art, the vehicle equipped with the evaporative purge system is
For example, when traveling in an area where the altitude above sea level is 2000 m or less (hereinafter referred to as lowland), the differential pressure between the pressure inside the canister and the negative pressure (boost pressure) inside the intake manifold becomes large, and the evaporation purge control valve is turned on. The relationship between the flow rate Q of the evaporative gas introduced into the intake manifold via the negative pressure P in the intake manifold is as shown by the characteristic line a shown by the solid line in FIG. When it reaches, the flow rate Q starts to increase, and when the negative pressure P increases to the pressure value P3 (for example, -550 mmHg), the flow rate Q increases to the maximum flow rate Q2.

On the other hand, for example, the vehicle has an altitude above sea level of 30.
When traveling in an area of 00m or more (hereinafter referred to as highland), the differential pressure between the pressure inside the canister and the negative pressure (boost pressure) inside the intake manifold becomes small, and the characteristic shown by the alternate long and short dash line in FIG. As shown by line b, negative pressure P is pressure value P2
Until it reaches (for example, -380 mmHg), the flow rate Q of the evaporative gas becomes (Q = 0), and even if the negative pressure P increases to the pressure value P3, the flow rate Q increases only to the flow rate Q1 (Q1 <Q2).

Therefore, in the prior art, when the vehicle equipped with the evaporative purge system travels in high altitudes, the atmospheric pressure is low and the differential pressure between the pressure in the canister and the negative pressure in the intake manifold becomes small, There is a problem that the flow rate of the evaporative gas introduced into the intake manifold is reduced, and the evaporative gas cannot always be effectively burned.

Therefore, as a result of studying the cause of the decrease in the evaporative gas flow rate at the time of traveling at high altitudes, the present inventors found that it was due to the decrease in the differential pressure between the negative pressure in the intake manifold and the pressure in the canister. In addition, it was also found that the flow rate of the evaporative emission gas decreases due to a relatively large pressure loss between the inflow port and the outflow port of the evaporation purge control valve provided in the evaporation purge passage.

The present invention has been made in view of the above-described problems of the prior art. Even when the pressure difference between the inlet side and the outlet side is small, the fluid is circulated smoothly from the inlet side to the outlet side. It is an object of the present invention to provide a solenoid valve that can be operated and can effectively increase the flow rate when the valve is opened.

[0012]

In order to solve the above-mentioned problems, a solenoid valve according to claim 1 has an inlet and an outlet, and a valve seat is formed between the inlet and the outlet. Valve case, a valve element that is disposed in the valve case and that is seated on and off the valve seat to communicate and block the inflow port and the outflow port, and the valve that seats the valve body on and off. An electromagnetic actuator provided in the case, wherein the outlet is
It is characterized in that it is formed in a Laval tube shape in which the diameter is tapered from the base end side near the valve seat toward the tip end side.

And, like the solenoid valve according to claim 2,
By integrally molding the valve case with a resin material, a valve seat is formed between the inlet and the outlet on one side in the axial direction, and the electromagnetic coil of the electromagnetic actuator is wound on the other side in the axial direction. It is desirable to form the bobbin part.

Further, as in the solenoid valve according to the third aspect, the electromagnetic actuator is formed of a magnetic material, and has a housing having an outer cylinder portion and a core extending in the axial direction, and is wound around the outer peripheral side of the core. And a magnetic plate embedded in the valve case made of a resin material and having a closed magnetic path formed between the housing and the valve body.

Further, as in the solenoid valve according to claim 4,
It is desirable to use the valve case as an evaporation purge control valve by connecting the inlet of the valve case with a canister for storing the evaporation gas from the fuel tank and connecting the outlet with the intake passage of the engine.

[0016]

With the above structure, when the fluid introduced into the valve case through the inflow port passes through the Laval tube-shaped outflow port, the flow velocity increases at the base end side having a smaller diameter, and It is led out to the tip side where the diameter becomes large. Therefore, the pressure of the fluid is decreased (the negative pressure is increased) on the tip side of the outflow port and the differential pressure with the inflow port side is increased, and the flow rate of the fluid flowing from the inflow port to the outflow port can be increased.

Further, by integrally molding the valve case including the bobbin portion with a resin material, the valve case and a part of the electromagnetic actuator can be integrated.

Further, the outer cylinder portion and the core of the housing are integrally formed of a magnetic material, and the magnetic plate is embedded in the valve case. It can be configured with a circuit, and furthermore, by connecting the inlet of the valve case to the canister and connecting the outlet to the intake passage of the engine and using it as an evaporation purge control valve, the pressure inside the canister and the negative pressure inside the intake passage can be reduced. Even if the differential pressure between and is small, the evaporation gas can be smoothly introduced into the intake passage.

[0019]

Embodiments of the present invention will be described below with reference to FIGS.

FIG. 1 shows an evaporation purge system in which the solenoid valve according to this embodiment is used as an evaporation purge control valve.

In FIG. 1, reference numeral 1 denotes an engine body mounted on a vehicle. The engine body 1 includes a multi-cylinder cylinder 2 (only one cylinder is shown), and a piston 3 that reciprocates in the cylinder 2. The cylinder head 4 is mounted on the cylinder 2. Reference numeral 5 denotes an intake passage connected to the intake side of the cylinder head 4.
An air cleaner 6 is provided on the tip side of the air cleaner 6, and a throttle valve 7 that is opened and closed to adjust the intake air amount is provided on the downstream side of the air cleaner 6.

In the intake passage 5, the downstream side of the throttle valve 7 serves as a collector 5A as an intake pool, and the downstream side of the collector 5A communicates with each cylinder 2 through an intake manifold 5B (only one is shown).
And, on the tip side of each intake manifold 5B,
A fuel injection valve 8 for injecting fuel is provided in each cylinder 2.

Reference numeral 9 denotes a fuel tank, and a fuel pump 10 is provided in the fuel tank 9. Then, by operating the fuel pump 10, the fuel in the fuel tank 9 is supplied to the fuel injection valve 8 through the fuel pipe 11.

A canister 12 communicates with the fuel tank 9 through a conduit 13, and the canister 12 contains an adsorbent 12A such as activated carbon. And the fuel tank 9
The evaporative gas generated inside is adsorbed by the adsorbent 12A to be temporarily stored in the canister 12. Reference numeral 14 denotes a check valve provided in the middle of the conduit 13, and the check valve 14 prevents the evaporative gas in the canister 12 from flowing back into the fuel tank 9.

Reference numeral 15 denotes an atmosphere introducing pipe having one end open to the canister 12 and the other end opening to the atmosphere.
A check valve 16 for preventing the evaporative gas in the canister 12 from being discharged into the atmosphere is provided in the middle of. Reference numeral 17 is an atmosphere opening port of the atmosphere introduction pipe 15 and a check valve 1
6 shows a drain cut valve interposed between the drain cut valve 17 and the air introduction pipe 15. The drain cut valve 17 connects the atmosphere introduction pipe 15 to the outside air when the engine is operating, and connects the atmosphere introduction pipe 15 when the engine is stopped. Shut off against outside air. Therefore,
When the engine is operating, the inside of the canister 12 is kept at a pressure equal to the atmospheric pressure.

Reference numeral 18 denotes an evaporation purge passage which connects the canister 12 and the intake manifold 5B, and two branch passages 19, 19 are provided in the middle of the evaporation purge passage 18.
19 are provided. Reference numeral 20 denotes a purge cut valve disposed upstream of each branch passage 19 of the evaporation purge passage 18, and the purge cut valve 20 opens the evaporation purge passage 18 when the throttle valve 7 is fully closed (idle time), for example. Before that, shut off the intake manifold 5
The introduction of evaporative gas into B is blocked, and the throttle valve 7
When is not fully closed (at the time of off idle), the evaporation purge passage 18 is communicated with the front and the rear.

Reference numerals 21 and 21 denote evaporative purge control valves as electromagnetic valves according to the present embodiment, which are respectively disposed in the middle of the respective branch passages 19. The respective evaporative purge control valves 21 include, for example, the throttle valve 7 fully opened. Alternatively, when fully closed, the branch passages 19 are shut off before and after each branch passage 19 from the evaporation purge passage 18 to the intake manifold 5B.
Prevent the introduction of evaporative gas into the. Further, when the throttle valve 7 is fully opened or an intermediate opening (partial range) other than fully closed, each evaporation purge control valve 21
To open the evaporation purge passage 18 and the respective branch passages 19 so that the evaporation gas is introduced into the intake manifold 5B.

Next, the evaporation purge control valve 21 will be described in detail with reference to FIGS.

In FIGS. 2 and 3, reference numeral 22 denotes a valve case formed of a resin material. On one axial side of the valve case 22, an inflow port 23 extending in the radial direction and an outflow port extending in the axial direction are provided. 24 and a valve seat 25 located between the inflow port 23 and the outflow port 24 and located on the proximal end side of the outflow port 24. The inflow port 23 and the outflow port 24 are shown in FIG.
As shown in FIG.
Via canister 12 and intake manifold 5B
Is connected between and.

Here, at the outlet 24, as shown in FIG. 4, a base end side opening 26A opening to the valve seat 25 side and a throat smoothly reduced in diameter with a predetermined curvature from the base end side opening 26A. Portion 26B, tip side opening portion 26C opening to the outside of the valve case 22, and throat portion 26B to tip side opening portion 2
Diffuser part 2 whose diameter gradually increases toward 6C
A Laval tube-shaped portion 26 composed of 6D is formed. In this example, when the diameter dimension of the most reduced diameter portion of the throat portion 26B is D, the axial dimension L1 from the opening end of the base end side opening portion 26A to the most reduced diameter portion of the throat portion 26B is (L1 = D), and the throat section 26B
The axial dimension L2 from the most reduced diameter portion to the opening end of the tip side opening 26C is set to (L2 = 6.5D). The angle θ of the diffuser portion 26D is set to 6 to 12 degrees.

Reference numeral 27 denotes a bobbin portion integrally formed with the valve case 22 and having a core insertion hole 28 on the inner peripheral side. The bobbin portion 27 has a pair of collar portions 27A, 27 spaced apart in the axial direction.
B is provided, and an electromagnetic coil 31 described later is wound between the collar portions 27A and 27B. Reference numeral 29 denotes a hollow portion provided in the valve case 22, the hollow portion 29 is located between the outlet 24 and the core insertion hole 28 and formed coaxially therewith,
An inflow port 23 is opened at the lower end side.

Reference numeral 30 denotes a magnetic plate embedded in the valve case 22 and made of a magnetic material. The magnetic plate 30 has an embedded portion 30A which is integrally embedded in the valve case 22 when the valve case 22 is molded. As shown in FIG.
It has a pair of flange portions 30B and 30B that project in the radial direction from A and have bolt holes (not shown) formed in the projecting end side. Further, in the buried portion 30A, for example, 9
4 with an angular interval of 0 degrees (only 2 shown in Figure 3)
Connection holes 30C, 30C, ... Of
The strength of the valve case 22 is secured by connecting the upper and lower parts of the magnetic plate 30 through the connecting holes 30C when the resin is molded.

Reference numeral 31 denotes an electromagnetic coil wound around the bobbin portion 27 of the valve case 22, and the electromagnetic coil 31 is connected to connectors 32, 32 protruding outside the valve case 22. Then, the electromagnetic coil 31 is excited by supplying a control current from a controller (not shown) through each connector 32.

Reference numeral 33 denotes a housing which covers the bobbin portion 27 of the valve case 22 together with the electromagnetic coil 31, and the housing 33 is made of a magnetic material from the outer tubular portion 34 and the lower portion of the outer tubular portion 34 as shown in FIG. Formed integrally from a pair of flange portions 35, 35 protruding outward in the radial direction and having bolt holes (not shown) on the protruding end side, and a hollow core 36 extending in the outer cylinder portion 34 in the axial direction. Has been done. Further, the inner peripheral surface of the core 36 serves as a guide hole 36A for guiding an adjusting rod 44 described later in the axial direction, and a female screw portion 36B is formed on the upper end side of the guide hole 36A. And housing 3
3 is the bobbin portion 2 of the valve case 22 on the inner peripheral side of the outer tubular portion 34.
7, the core 36 is inserted into the core insertion hole 28 and assembled to the valve case 22, and each flange portion 35 and each flange portion 30B of the magnetic plate 30 embedded in the valve case 22 are attached. , Bolts 37, 37 and nuts 38,
It is fixed by 38.

In this way, by only assembling the valve case 22 and the housing 33, which are integrally formed, the outer cylinder portion 34 and the core 36 of the housing 33, and the magnetic plate 30 embedded in the valve case 22. A closed magnetic circuit of the magnetic circuit is formed, and these constitute an electromagnetic actuator 39 together with the electromagnetic coil 31.

40 is a collar portion 27A, 27B of the bobbin portion 27.
The protective cylinder 40 is interposed between the outer cylindrical portion 34 of the housing 33 and the outer cylindrical portion 34 of the housing 33. The protective cylinder 40 is formed of a resin material in a cylindrical shape and covers the electromagnetic coil 31 wound around the bobbin portion 27 of the valve case 22. ing. The protection cylinder 40 protects the electromagnetic coil 31 from the outside and also insulates the electromagnetic coil 31 from the housing 33 and the like. Reference numeral 41 is an O-ring which is arranged between the collar portion 27A of the bobbin portion 27 and the base end side of the core 36 and seals between the valve case 22 and the housing 33.

Reference numeral 42 designates a valve element located in the hollow portion 29 of the valve case 22 and disposed between the valve seat 25 and the lower end side of the core 36. The valve element 42 is made of a magnetic material in a tubular shape. The valve main body 42A is formed, and the valve portion 42B made of an elastic body is baked and integrated with the valve main body 42A. Then, the valve body 42 shuts off between the inflow port 23 and the outflow port 24 of the valve case 22 by seating the valve portion 42B on the valve seat 25 when the electromagnetic coil 31 is demagnetized.
When the electromagnetic coil 31 is excited, the valve seat 25 moves to the valve portion 4
By separating 2B, the inlet 23 of the valve case 22
Communicate with the outlet 24.

Reference numeral 43 denotes a valve element 42 and an adjusting rod 44 described later.
The valve spring 43 is formed of a coil spring, and constantly urges the valve element 42 toward the valve seat 25. Reference numeral 44 denotes an adjusting rod inserted into the guide hole 36A of the core 36. The adjusting rod 44 has a male screw portion 44A formed on the upper end side thereof and an engaging projection 44 on the lower end side thereof.
B is formed. Then, the adjusting rod 44 engages one end portion of the valve spring 43 with the engaging protrusion 44B to cause the core 36 to move.
Of the valve body 42 by inserting the male screw portion 44A into the female screw portion 36B of the core 36 by inserting the male screw portion 44A into the guide hole 36A.
The biasing force of the valve spring 43 with respect to is adjusted. 45 is disposed in the axially intermediate portion of the adjusting rod 44,
O for sealing between the housing 33 and the adjusting rod 44
It's a ring.

The evaporative purge control valve 21 according to the present embodiment has the above-mentioned structure. When the electromagnetic coil 31 of the electromagnetic actuator 39 is demagnetized, the valve portion 42B of the valve body 42 is urged by the valve spring 43. It sits on the valve seat 25, and shuts off between the inflow port 23 and the outflow port 24. When the electromagnetic coil 31 is excited, the outer tube portion 34 of the housing 33, the core 36, the magnetic plate 30,
A closed magnetic circuit including the valve body 42A is formed, the valve portion 42B of the valve body 42 is separated from the valve seat 25 against the biasing force of the valve spring 43, and the inflow port 23 and the outflow port 24 communicate with each other.

When the inflow port 23 and the outflow port 24 communicate with each other, the evaporative gas introduced into the valve case 22 through the inflow port 23 becomes a small diameter of the Laval tube shaped portion 26 formed in the outflow port 24. By passing through the throat portion 26B, the valve case 22 is passed through the diffuser portion 26D and the front end side opening portion 26C in a state where the flow velocity is accelerated.
Derived out of.

As a result, the negative pressure generated on the downstream side of the throat portion 26B increases and the differential pressure from the pressure on the inflow port 23 side increases, so that the evaporation gas stored in the canister 12 is discharged from the evaporation purge passage 18 and each of the evaporation purge passages 18. Inlet 23 of each branch passage 19 and each evaporation purge control valve 21
And intake manifold 5B smoothly through the outlet 24
Flow rate of the evaporative gas introduced into the intake manifold 5B increases.

Here, the relationship between the flow rate Q of the evaporative gas introduced into the intake manifold 5B and the negative pressure P in the intake manifold 5B at the time of traveling at high altitude is shown by a solid line in FIG. The characteristic line c when the valve 21 is used is compared with the characteristic line b when the prior art evaporation purge control valve shown by the alternate long and short dash line is used.

First, in the characteristic line b, the flow rate Q of the evaporative gas is (Q = 0) until the negative pressure P reaches the pressure value P2.
Therefore, even if the negative pressure P increases to the pressure value P3, the flow rate Q increases only to the flow rate value Q1.

On the other hand, in the characteristic line c, when the negative pressure exceeds the pressure value P1, the flow rate Q starts to increase, and when the negative pressure P increases to the pressure value P1 '(before and after -200 mmHg), the flow rate Q increases. Increases to a flow rate value Q1 '(Q1 <Q1'). A characteristic line a indicated by a chain double-dashed line in FIG. 5 shows the relationship between the evaporative gas flow rate Q and the negative pressure P during the lowland traveling described above with reference to FIG. Such characteristics can be obtained.

That is, by using the evaporation purge control valve 21 according to the present embodiment as the evaporation purge control valve, the intake manifold 5B can be compared with the case where the evaporation purge control valve according to the prior art is used.
The flow rate of the evaporative gas introduced into the inside can be increased, and the evaporative gas can be effectively burned even when traveling at high altitudes.

In the above embodiment, when the shape of the Laval tube shaped portion 26 provided at the outlet 24 of the valve case 22 shown in FIG. 4 is D, the diameter of the most reduced diameter portion of the throat portion 26B is D. , From the opening end of the base end side opening 26A to the throat portion 2
The axial dimension L1 to the most reduced diameter portion of 6B is (L1 = D), and the most reduced diameter portion of the throat portion 26B to the tip side opening 26
Axial dimension L2 to the open end of C (L2 = 6.5D)
The angle θ of the diffuser portion 26D is set to 6 to 12 degrees, but these dimensions D, L1, L2 and θ are the specifications of the environment in which the vehicle equipped with the evaporative purge system is placed and the control of the evaporative gas. You may change suitably according to the etc.

Further, in the above-mentioned embodiment, an example in which the solenoid valve according to the present invention is applied to the evaporation purge control valve provided in the evaporation purge passage has been described, but the present invention is for opening and closing the gas passage which constitutes such a pneumatic circuit. Not only the solenoid valve but also the solenoid valve for opening and closing the liquid passage forming a hydraulic circuit such as a fuel injection valve may be used.

[0048]

As described in detail above, according to the invention of claim 1, the fluid introduced into the valve case through the inflow port has its flow velocity when passing through the outflow port formed in the Laval tube shape. Is discharged to the outside of the outlet while being accelerated,
The negative pressure generated on the outlet side will increase. Therefore,
Even if the differential pressure between the pressure on the inlet side and the pressure on the outlet side is small, the negative pressure generated on the outlet side increases, so that the flow rate of the fluid flowing from the inlet side to the outlet side can be increased. .

According to the second aspect of the present invention, the valve case, including the bobbin portion, can be integrally molded with the resin material. Therefore, the valve case and the electromagnetic actuator are partly integrated to form a component. The number of points can be reduced.

According to the third aspect of the present invention, the valve case is constituted by the housing having the outer cylinder portion and the core, the magnetic plate embedded in the valve case, and the electromagnetic coil wound around the bobbin portion of the valve case. Just assemble the housing to
Since the electromagnetic actuator can be configured by the closed magnetic circuit of the magnetic circuit, the assembling property can be remarkably improved.

Further, according to the invention of claim 4, the inlet of the valve case is connected to the canister, and the outlet is connected to the intake passage of the engine to be used as an evaporation purge control valve. Even when the pressure difference between the pressure in the canister and the negative pressure in the intake passage is small, the evaporated gas stored in the canister can be smoothly introduced into the intake passage, and the evaporated gas is effectively burned. be able to.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an evaporation purge system to which an evaporation purge control valve according to an embodiment of the present invention is applied.

FIG. 2 is an external view showing an evaporation purge control valve according to an embodiment of the present invention.

3 is a vertical cross-sectional view as seen from the direction of arrows III-III in FIG.

FIG. 4 is a vertical cross-sectional view showing an enlarged outlet and the like in FIG.

FIG. 5 is a characteristic diagram showing the relationship between the negative pressure in the intake manifold and the flow rate of evaporative gas.

FIG. 6 is a characteristic diagram showing a relationship between a negative pressure in an intake manifold and a flow rate of evaporation gas according to a conventional technique.

[Explanation of symbols]

 5 intake passage 5B intake manifold 12 canister 18 evaporation purge passage 19 branch passage 21 evaporation purge control valve 22 valve case 23 inflow inlet 24 outflow outlet 25 valve seat 26 Laval tube shape portion 27 bobbin portion 30 magnetic plate 31 electromagnetic coil 33 housing 34 outer cylinder Part 36 core 42 valve body

Claims (4)

[Claims] 1. A valve case having an inflow port and an outflow port, wherein a valve seat is formed between the inflow port and the outflow port, and the inflow port and the outflow port disposed in the valve case. In an electromagnetic valve including a valve body that is seated on and off from the valve seat to communicate with and shut off, and an electromagnetic actuator provided on the valve case to seat the seat, the outflow port is An electromagnetic valve characterized by being formed in a Laval tube shape in which a diameter is tapered to expand from a base end side close to a valve seat toward a tip end side. 2. The valve case is integrally formed of a resin material to form a valve seat between the inlet and the outlet on one side in the axial direction, and the electromagnetic actuator of the electromagnetic actuator on the other side in the axial direction. The solenoid valve according to claim 1, wherein the solenoid valve forms a bobbin around which the coil is wound. 3. The electromagnetic actuator is made of a magnetic material, and has a housing having an outer cylinder portion and a core extending in the axial direction, an electromagnetic coil wound around the outer periphery of the core of the housing, and a resin material. The solenoid valve according to claim 1, wherein the solenoid valve is composed of a magnetic plate embedded in the valve case and having a closed magnetic path formed between the housing and the valve body. 4. The evaporation purge control valve according to claim 1, wherein an inlet of the valve case is connected to a canister for storing evaporation gas from a fuel tank, and the outlet is connected to an intake passage of an engine. The solenoid valve described.