JPH06299929A - Electromagnetic fuel injection valve - Google Patents

Abstract

PURPOSE:To provide a side feed type electromagnetic fuel injection valve, which escapes from erosion in a coil part, even when a fuel including various additives such as alcohol is used and is provided with high reliability. CONSTITUTION:The whole of a bobbin 11, on which a coil 2 is wound, and a part of a terminal lead member 22 are covered by a resin layer 50, whose outer circumference is provided with an exterior mold 10. In this way, sealing performance, which is not sufficiently achieved only by the exterior mold 10, is surely made up by the resin layer 50, and penetration of a fuel to a connection part between the coil 2 and the terminal lead member 22 is suppressed, so that breakage in the coil is eliminated even when an erosive fuel including various additives such as alcohol is used, and consequently, a fuel injection valve provided with high reliability can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side-feed type electromagnetic fuel injection valve, and more particularly to a fuel injection valve suitable for an internal combustion engine such as a gasoline engine for automobiles.

[0002]

2. Description of the Related Art In recent years, in gasoline engines for automobiles and the like, the temperature rise in the room has been remarkably increased due to higher output and downsizing of the engine room, and the fuel injection valve is exposed to a high temperature atmosphere. Therefore, in the electromagnetic fuel injection valve, a so-called side feed type fuel injection valve has been used in which fuel is introduced through the outer circumference of the coil to cool the coil. ing.

Therefore, in the electromagnetic fuel injection valve according to the prior art, as shown in, for example, Japanese Patent Laid-Open No. 4-136474, an outer mold is applied to the outer circumference of the bobbin around which the coil is wound, or the coil is wound. The entire surface of the bobbin around which the coil was wound was covered with an outer mold to prevent the coil from directly contacting the fuel.

[0004]

In the above-mentioned prior art, it cannot be said that the coil sealing is sufficiently taken into consideration. Corrosion is induced at the joint between the coil and the terminal lead member to cause a disconnection failure. There was a problem. That is, of the above-mentioned conventional techniques, first, in the fuel injection valve in which the outer mold is applied to the outer circumference of the bobbin around which the coil is wound,
Even if the outer mold is applied, the boundary between the bobbin and the outer mold is not completely fused, and when exposed to the fuel and repeated cold heat, the fuel flows from the boundary to the coil part. There is a possibility that it will invade.

Further, in the fuel injection valve in which the entire surface of the bobbin around which the coil is wound is covered with the outer mold, a part of the bobbin is received by the outer mold during the molding process in the manufacturing process. It must be fixed, and a joint boundary between the bobbin and the exterior is always formed at that portion, and the fuel permeates from this portion.

Further, in this prior art, when the exterior molding is performed without receiving the bobbin with the mold, the position of the bobbin becomes unstable during the molding.
There is a risk that part of the bobbin will be exposed to the outside of the exterior, and as a result, the fuel will penetrate from there and cause problems such as disconnection, so it cannot be said to be perfect. It was

Further, according to this conventional technique, when the exterior is molded without receiving the bobbin with the mold, the position of the bobbin is displaced and the terminal lead member integrally attached to the bobbin is bent. Then, there is a possibility that this may cause stress corrosion cracking of the lead member.

In particular, in recent years, depending on the market, it has been approved by law to add alcohol and other additives to fuels, and further, in alternative fuels used in FFV (flexible fuel vehicle), etc., Methyl alcohol has been added up to 85%, and when such fuel enters the coil part, corrosion may occur not only in the coil joint but also in the coil itself. In this case, in the conventional technique, the possibility of the disconnection failure is further increased.

The object of the present invention is to reliably prevent the fuel from entering the coil portion even if the fuel containing various additives is used, and to prevent the coil from being broken or the like. It is to provide an electromagnetic fuel injection valve having high performance.

[0010]

The above object is achieved by first covering the entire outer and inner circumferences of a bobbin around which a coil is wound with a resin, and then applying an outer mold to the outer circumference. Further, at this time, the above-mentioned object is further sufficient by using a method of covering the entire inner circumference of a coil wound bobbin with a resin without applying a mold to the resin during the coating treatment with resin. This is achieved in a form that is guaranteed by, for example, a dipping method (dip coating) in which a bobbin wound with a coil around a molten resin is covered by dripping, or a spray method in which the molten resin is sprayed and sprayed. Etc. may be used.

[0011]

Function: By covering the entire inner and outer circumferences of the bobbin wound with the coil with the resin before the outer molding, and at this time, by covering with the resin by the dipping method or the spray method, Since the joint surface between the outer mold and the bobbin or the terminal lead member is located outside the outer mold, even if fuel enters between the outer mold and this resin, the fuel enters the coil part or the joint part of the coil. Therefore, it is possible to reliably suppress the occurrence of disconnection of the coil and disconnection due to corrosion of the joint portion of the coil.

[0012]

The electromagnetic fuel injection valve according to the present invention will be described in detail below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention, in which a yoke mold 1, a coil 2, a core (fixed iron core) 3, a case 4, and a plunger 5 are shown.
Etc. are the main elements, and the magnetic circuit by the coil 2 is formed by the core 3, the case 4, and the plunger 5. A plunger 5 is provided inside the core 3, and a ball valve 6 and a spring 9 for pressing the ball valve 6 against the seat surface 8 of the nozzle 7 are further provided.

The coil 2 is wound around the bobbin 11,
Although housed between the core 3 and the case 4, the coil 2 has an exterior mold 10 that wraps the outside thereof, and between the coil 2 and the bobbin 11 and the exterior mold 10.
Further, a resin layer 50 is provided so as to cover the entire coil 2 and bobbin 11.

An O-ring 12 is provided between the case 4 and the outer mold 10 and between the core 3 and the outer mold 10 to seal the fuel which is about to leak to the outside through the gap.
And an O-ring 51. A hole through which the terminal lead member 22 that serves as a terminal of the coil 2 passes is provided in the upper portion of the core 3, and the O-ring 2 is provided between the hole and the terminal lead member 22.
3 and a plug 24 for preventing the yoke mold 1 from entering the hole.

The case 4 is provided with an O-ring 13, a fuel passage 14, a filter 15 on the outer periphery thereof, a stopper 16, and a nozzle member 7 having a swirler 17 inside. Furthermore, on the upper part of the case 4, the connector terminal 1 connected to the terminal lead member 22 of the coil 2 is provided.
8 and the terminal 18 are surrounded to form a connector,
The yoke mold 1 is provided so as to cover the entire upper portions of the core 3 and the case 4.

A ball valve 6 and a guide ring 19 are integrally connected to the plunger 5, and the guide ring 19 is connected to the core 3
It is inserted in the inner diameter portion 20 at the tip of the cylindrical portion of and is guided by this inner diameter portion 20. In the nozzle member 7,
A swirler 17 that guides the ball valve 6 and gives a swirling force to the injected fuel is provided, and an O-ring 21 is provided on the outer periphery thereof.

FIG. 2 shows the bobbin 11 and the coil 2 taken out to the outside. As is clear from this figure, the entire inner and outer circumferences of the bobbin 11 and the coil 2 are oil-resistant and chemical-resistant. Is covered with the resin layer 50. This resin 5
0 is formed by a dipping method (dip coating) in which the bobbin 11 and the coil 2 are dipped in a molten resin without using a mold, or a spray method in which the molten resin is sprayed and sprayed. Therefore, the connecting portion 52 is only the upper portion of the joint portion 53 of the terminal lead member 22, and this portion is located outside the exterior mold 10. Therefore, the coil 2 and the joint portion 53 between the coil 2 and the terminal lead member 22 are in a form of being enclosed in the resin layer 50.

Next, the assembly consisting of the bobbin 11 and the coil 2 and provided with the resin layer 50 is covered with the exterior mold 10 as shown in FIG. The exterior mold 10 is molded by the injection molding method like the exterior mold in the conventional example, and is also formed including a portion where dimensional accuracy is required, such as a storage portion for the O-rings 12 and 51. At the time of this molding, injection molding is performed with a part of the resin layer 50 received and fixed by a mold.

The assembly of the bobbin 11 and the coil 2 thus provided with the exterior mold 10 is assembled in the case 4 via the O-rings 12, 51 and 23. At this time,
The O-ring 23 is adapted to be attached outside the exterior mold 10 to a portion of the terminal lead member 22 where the resin layer 50 is provided.

Next, the operation of the electromagnetic fuel injection valve according to the embodiment of the present invention thus assembled will be described. When an electric signal is applied to the coil 2, a magnetic circuit composed of the core 3, the case 4, and the plunger 5 is formed, and the plunger 5 is guided by the core 3 and the swirler 17 on the outer circumference of the guide ring 19 and the ball valve 6. Core 3 in the state
Is sucked into. The plunger 5 is integrally connected to the ball valve 6, and therefore, when the plunger 5 moves to the core 3 side, the ball valve 6 is moved to the seat surface 8 of the nozzle member 7.
And the valve is opened.

On the other hand, the fuel is pressurized and adjusted by a fuel pump and a fuel pressure regulator (not shown), passes through the fuel passage 14 of the case 4, passes between the case 4 and the outer mold 10, and passes between the plunger 5 and the case 4. Flow, sheet surface 8
Is supplied at the top of. Then, the fuel supplied to the upper portion of the seat surface 8 is given a turning force by the swirler 17 when the valve is opened, and is injected outside the injection valve through the orifice 25. At this time, the swirler 17 gives a turning force, so that atomization of the fuel is promoted.

Next, the coil portion, which is a feature of this embodiment, will be described. The entire coil portion including the bobbin 11 and the coil 2 is soaked in the fuel, and at this time, at the boundary surfaces 54 and 55 between the resin layer 50 and the exterior mold 10, the resins do not completely fuse with each other. When the fuel is actually used and the fuel is repeatedly subjected to cold pressure and heat, there is a possibility that the fuel may intrude into the inside from the boundary surface portion. In this embodiment, the coil 2 or the coil 2 and the terminal lead member is used. Since the joint portion 53 of 22 is covered with the resin layer 50, it is not exposed to the fuel.

Even if the fuel enters between the resin layer 50 and the outer mold 10, since the O-ring 23 is provided in this embodiment, it does not leak to the outside of the injection valve. Therefore, according to this embodiment, the fuel containing alcohol and other additives is used, and even if pressure or cold heat is applied, the fuel is not applied to the coil 2 or the connecting portion 53 between the coil 2 and the terminal lead member 22. Does not occur at all, so disconnection failure does not occur and sufficiently high reliability can be easily ensured.

By the way, the resin layer 50 in this embodiment
As the material of, for example, a resin suitable for spraying and a dipping method that has oil resistance and chemical resistance and that can easily cover the entire inner and outer circumferences of the coil portion is required. As the resin, an epoxy-based synthetic resin and a phenol-based synthetic resin are known. Therefore, in this embodiment as well, the resin layer 50 is formed by using the epoxy-based synthetic resin or the phenol-based synthetic resin, but in addition to this, any resin material may be used as long as the above-mentioned conditions are satisfied. Needless to say, it may be formed.

The epoxy-based synthetic resin and the phenol-based synthetic resin are not limited to substantially pure simple substances, but include other solvents and are supplied as paints or adhesives. 50 may be formed, and the same effect can be obtained.

[0026]

According to the present invention, even if the fuel containing various additives is used, it is possible to surely prevent the fuel from entering the coil portion, so that the coil may be broken. Therefore, it is possible to easily provide a highly reliable electromagnetic injection valve.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an electromagnetic fuel injection valve according to the present invention.

FIG. 2 is a front view showing a bobbin-coil assembly according to an embodiment of the present invention.

[Explanation of symbols]

 1 yoke mold 2 coil 3 core 4 case 9 spring 10 exterior mold 11 bobbin 19 guide ring 22 terminal lead member 50 resin layer 52 joint portion 53 coupling portion between coil and terminal lead member 54, 55 joint portion between resin layer and exterior mold

Claims (2)

[Claims] 1. A side-feed type electromagnetic fuel injection valve in which a bobbin around which a coil is wound is externally molded to form an electromagnetic coil for driving a valve element, and a bobbin around which the coil is wound An electromagnetic fuel injection valve, comprising a resin layer on the entire surface, and the exterior mold provided on the outer periphery thereof. 2. The invention according to claim 1, wherein the resin layer is composed of at least one of an epoxy resin and a phenol resin formed by at least one of a dipping method and a spray method. Electromagnetic fuel injection valve.