JPH06235359A - Electromagnetic type fuel injection valve - Google Patents

Abstract

PURPOSE:To prevent the intrusion of fuel to a coil part even if the fuel containing a variety of additives is used and prevent the breakage of the coil, by covering the inner and outer peripheries of a bobbin consisting of the winding of coils with the oil-resistive and chemical-resistive resin and applying an outer decoration molding on the outer periphery. CONSTITUTION:The whole of the inner and outer peripheries of a bobbin 11 and a coil 2 are covered by the oil-resistive and chemical-resistive resin 50. Because of the dipping method utilizing the dipping into the molten resin 50, the joint part exists only at a connector part, and this part is positioned outside an outer decoration molding. Accordingly, the coil 2 and the joint part between the coil 2 and the connector 22 are enclosed inside the resin 50. Further, the bobbin coil assembly body is covered by an outer decoration mold 10. The outer decoration mold 10 is formed through the injection molding method, and a part of the resin 50 is received by a mold and fixed, and the injection molding is carried out. Accordingly, even if the fuel containing a variety of additives is used, the intrusion of fuel to the coil part is prevented, and the breakage of the coil 2 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fuel injection valve,
In particular, the present invention relates to an electromagnetic fuel injection valve bobbin suitable for an internal combustion engine fuel injection valve.

[0002]

2. Description of the Related Art In a conventional fuel injection valve, an outer mold is applied to the outer circumference of a coil-wound bobbin, but the boundary between the bobbin and the outer mold is not completely fused and exposed to the fuel. When the cold heat is repeated, the fuel enters the coil from the boundary. In recent years, fuels have been legally approved by the market to add alcohol and other additives, and FFV
As an alternative fuel, methyl alcohol is being added in an amount of 0 to 85%. When such a fuel enters the coil, the coil disconnection or the coil joint corrosion occurs and the injection valve There is a risk of malfunctions that will not operate.

There is an example in which the coil portion is entirely covered with an outer mold as shown in Japanese Patent Laid-Open No. 4-136474, but when molding, a part of the bobbin is received and fixed by the outer mold die. It must be done, and the bobbin-outer joint boundary always appears at that part. If you do, fuel will penetrate from that part. Furthermore, if the exterior is molded without receiving the bobbin, the position of the bobbin may become unstable during molding, and a part of the bobbin may appear on the outside of the exterior. It was not perfect because it could cause Further, when the exterior is molded without receiving the bobbin, the position of the bobbin is displaced and the connector integrally attached to the bobbin is bent, which may cause stress corrosion cracking of the connector.

[0004]

In recent years, in the injection valve, the temperature applied to the injection valve becomes higher due to the higher output of the engine and the downsizing of the engine room, so that the outer circumference of the coil is cooled with fuel for cooling. A side-feed type injection valve is required. Therefore, since the fuel flows to the outer circumference of the coil, an outer mold is applied to the coil so that the coil does not come into direct contact with the fuel, but since the joint boundary surface between the bobbin and the outer mold does not completely fuse, If it is soaked and cold heat is repeated in the specified state, a gap may be created at the joint and fuel may enter the coil. In recent years, it has been legally permitted to include a few percent of alcohol and other additives in fuels. Furthermore, as in FFV, 0 to 85% of methyl alcohol is mixed as an alternative fuel. Consideration to use it has begun. When such fuel enters the coil portion, there is a possibility that a portion where the coil coating is flawed or a joint portion between the coil and the connector is corroded, leading to disconnection and the injection valve does not operate.

An object of the present invention is to provide a highly reliable injection valve in which the fuel does not enter the coil portion and the coil is not broken even if the fuel containing various additives is used.

[0006]

In order to achieve the above object, the present invention is to cover the entire outer and inner circumferences of a coil-wound bobbin with resin and to apply an outer mold to the outer circumference. Moreover, the dipping method is one in which the resin on the inner and outer circumferences of the bobbin around which the coil is wound is entirely covered without applying pressure, for example, the resin is dipped in a melted resin and covered.

[0007]

Operation: By covering the entire inner and outer circumferences of the bobbin around which the coil is wound with resin before exterior molding, and by covering with a resin such as a dipping method, the joint surface between the resin and the bobbin or the connector can be covered. Since it is located outside the exterior mold, even if fuel enters between the exterior mold and this resin, the fuel does not enter the coil part or the joint part of the coil. Problems such as disconnection due to corrosion do not occur.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The magnetic circuit is composed of a fixed iron core (core) 3, a case 4, and a plunger 5. Inside the core 3, a spring 9 for pressing a valve body composed of the plunger 5 and a ball valve 6 against the seat surface 8 of the nozzle 7 is provided. It is provided. Further, between the core 3 and the case 4, the coil 2 wound around the bobbin 11 that excites the magnetic circuit, the outer mold 10 that encloses the coil 2, the coil and the bobbin, and the entire coil and bobbin are covered. Thus, the resin layer 50 is provided. An O-ring 12 and an O-ring 51 are provided between the case 4 and the outer mold 10 and between the core 3 and the outer mold 10 to seal fuel leaking to the outside through the gaps. A connector 2 that sends a signal to the coil 2 is provided above the core.
An O-ring 23 and a plug 24 for preventing the yoke mold from entering are provided between the two. 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 7 having a swirler 17 for guiding the ball valve 6 therein. Further, a terminal 18 for transmitting a signal to the coil 2 and a yoke mold 1 which surrounds the terminal and forms a connector and which covers the entire core and the upper portion of the yoke are provided on the upper portion of the case 4. The valve body is
The plunger 5, the ball valve 6, and the guide ring 19 are integrally connected, and the guide ring 19 is guided by the inner diameter 20 of the tip of the core 3. The nozzle 7 is provided with a swirler 17 for guiding the ball valve 6 and giving a swirling force to the fuel, and an O-ring 21 on the outer circumference of the nozzle. Bobbin 11 and coil 2
As shown in FIG. 2, the entire inner and outer peripheries are covered with oil- and chemical-resistant resin 50. This resin 50 is connected by a dipping method in which it is dipped in melted resin.
Is only the upper part of the connector, and this part is located outside the outer mold. Therefore, the coil and the joint portion 53 of the coil and the connector are enclosed in the resin 50. The bobbin coil assembly is then covered by the outer mold 10. The exterior mold 10 is molded by the same injection molding method as that of the conventional exterior mold, and the O-ring housing portion and the like where dimensional accuracy is required are also molded. During the molding, a part of the resin 50 is received by a mold and fixed, and injection molding is performed.
The externally molded assembly is O inside the core 3 and case 4.
Assembled through the rings 12, 51, 23, the O-ring 23 is attached to the connector 22 outside the outer mold.

Based on the above structure, the operation of the injection valve will be described. When an electric signal is applied to the coil 2, a magnetic circuit is constituted by the core 3, the case 4 and the plunger 5, and the plunger 5 is guided by the core 3 and the swirler 17 around the guide ring 19 and the ball valve 6 to the core 3 side. Sucked. The plunger 5 is integrally connected to the ball valve 6, and when the plunger 5 moves, the ball valve 6 also moves and separates from the seat surface 8 of the nozzle 7 to open the valve. The fuel is pressurized and adjusted by a fuel pump and a fuel pressure regulator, flows through the fuel passage 14 of the case 4 inside the injection valve, between the case 4 and the outer mold 10, and between the plunger 5 and the case 4, and the seat It is supplied to the upper part of the section 8. The swirler 17 gives a swirling force to the fuel supplied to the upper portion of the seat portion 8, and the fuel is injected to the outside of the injection valve through the orifice 25.

Next, the coil portion will be described. The coil portion is immersed in the fuel, and the resin 10 and the outer mold 1
At the boundary surfaces 54 and 55 of 0, the resins are not completely fused with each other. Therefore, in actual use, when pressure or cold heat is applied, the fuel may intrude into the inside from that portion.
Since the joint portion 53 of the coil 2 and the connector is covered with the resin 50, it is not exposed to the fuel. Further, the fuel that has entered between the resin 50 and the outer mold 10 does not go out of the injection valve by the O-ring 23 provided outside the outer mold. Here, the resin 50 is, for example, an epoxy resin having oil resistance and chemical resistance.

Under the above-mentioned structure, even if the fuel is immersed in the fuel containing alcohol and other additives, and the pressure or cold heat is applied, the fuel may enter the coil or the connecting portion of the coil and the connector. No problem due to disconnection.

Similar effects can be obtained by using a resin capable of dipping, a resin capable of being coated by dipping or another coating method, or an adhesive as the resin 50.

[0013]

According to the present invention, it is possible to provide a highly reliable injection valve in which the fuel does not enter the coil portion and the coil is not broken even if the fuel containing various additives is used. it can.

[Brief description of drawings]

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Yoke mold, 2 ... Coil, 3 ... Core, 4 ... Case, 9 ... Spring, 19 ... Guide ring, 11 ... Bobbin, 10 ... Exterior mold, 22 ... Connector, 50 ... Resin, 52 ... Joint part, 53 ... Coil, connector joint,
54, 55 ... Resin, exterior molding joint.

Claims (2)

[Claims] 1. An exciting coil fixed inside an injection valve main body, a bobbin holding the coil, an exterior mold enclosing the coil portion, a fixed iron core, and a coil assembly including a case, and the fixed iron core (hereinafter A movable iron core (hereinafter referred to as the plunger) that moves in opposition to the core) is attracted to the core side by exciting the coil assembly, and a valve provided on the opposite side of the plunger core from the valve seat. In an electromagnetic fuel injection valve for an internal combustion engine having a structure for injecting fuel by separating it, the coil bobbin is covered with oil and chemical resistant resin on its inner and outer circumferences, and its outer circumference is externally molded. An electromagnetic fuel injection valve characterized in that 2. The electromagnetic fuel injection valve according to claim 1, wherein the resin is an epoxy resin.