JP2003083198A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection valve capable of air-tightly fixing a valve part and an electromagnetic driving part by a resin covering member for coating the electromagnetic driving part mounted on the valve part. SOLUTION: This fuel injection valve comprises a metallic inner cylindrical member 14 in which a movable element 25 and a valve member 26 fixed to the movable element 25 are axially reciprocatively accommodated to form a part of a magnetic circuit for driving the movable element 25, a metallic outer frame member 23 mounted on an outer periphery of the metallic inner cylindrical member 14 through a driving coil C and abutting on the metallic inner cylindrical member 14 at its tip part to form another part of the magnetic circuit, and a resin coating member 13 coating an outer peripheral face of the metallic outer frame member 23 over the whole face, and attached to the metallic inner cylindrical member 14. A coating tip part of the resin coating member 13 is attached to a sidewall of an annular step part 14h of the metallic inner cylindrical member 14, and a recessed part 14j filled with an adhesive for adhering the resin coating member 13 and the metallic inner cylindrical member 14, is formed near the side wall.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel injection valve.

[0002]

2. Description of the Related Art As a fuel injection valve used in, for example, an internal combustion engine for automobiles, in order to accurately adjust the fuel injection amount, the valve portion is opened and closed by an electromagnetic drive portion and opened. It is known that the valve period is variably adjusted.

This type of fuel injection valve covers the electromagnetic drive part mounted on the valve part with a resin molding member such as a resin mold as a means for fixing the electromagnetic drive part to the valve part,
The valve portion and the electromagnetic drive portion are adhered and fixed.

[0004]

In the conventional structure, the heat generated by the operation of the fuel injection valve or the like causes a difference in thermal contraction and expansion between the resin molding member and the valve portion which is a metal member. There may be a gap between the members. In some cases, water or the like may enter through this gap, causing a functional deterioration due to internal corrosion of the electromagnetic drive unit.

The present invention has been made in consideration of the above circumstances, and an object thereof is to hermetically seal the valve portion and the electromagnetic drive portion by a resin jacket member covering the electromagnetic drive portion mounted on the valve portion. The object of the present invention is to provide a fuel injection valve that can be attached and fixed to a vehicle.

[0006]

According to a first aspect of the present invention, a movable body and a valve member engaged with the movable body are accommodated so as to be reciprocally movable in the axial direction, and the movable body is driven. A metal inner tubular member that constitutes a part of the magnetic circuit, a drive coil that operates the magnetic circuit, and a drive coil that is disposed on the outer periphery of the metal inner tubular member with the drive coil sandwiched between the metal inner tubular member and another part of the magnetic circuit. A metal outer frame member, the tip of which abuts against the inner metal tube member, and a resin outer cover member that covers the outer peripheral surface of the outer metal frame member over the entire circumference and is attached to the inner metal tube member. The tip of the mantle is adhered to the side wall of the annular stepped portion formed on the outer peripheral side of the metal inner cylinder member, and the resin mantle member and the metal inner cylinder member are bonded near the side wall of the metal inner cylinder member. There is a recess filled with the adhesive.

Generally, in a case where different members such as a resin material and a metal material are integrally fixed by insert molding or the like, due to thermal strain caused by the difference in thermal expansion and contraction between the resin material and the metal material, these different members are A gap is likely to occur at the butted portion. That is, a metal inner cylinder member that accommodates the movable body and the valve member in a reciprocating manner, and a metal outer frame member that sandwiches the drive coil on the outer circumference of the metal inner cylinder member, In a magnetic circuit operated by a drive coil by covering the entire circumference and adhering to the metal inner cylinder member, in a resin outer member and a metal inner cylinder adhered to the metal inner cylinder member due to thermal strain. There is a possibility that a gap will be formed between the member and the water, and the like, which penetrates into the gap, may cause a functional deterioration due to corrosion of the drive coil and the like inside.

On the other hand, in the fuel injection valve of the present invention,
Since the recess filled with the adhesive that bonds the resin outer jacket member and the metal inner cylinder member is provided in the vicinity of the side wall of the annular stepped portion to which the outer shell tip of the resin outer jacket member is adhered, the metal inner cylinder member is covered. The outer tip of the outer jacket and the outer periphery of the inner metal tube member are airtightly formed by an adhesive, and thus the joining force can be improved to make the outer tip of the outer jacket and the outer periphery of the inner metal tube member airtight.

Therefore, even if a gap occurs between the outer jacket tip portion of the resin jacket member and the side wall of the metal inner cylinder member due to thermal strain, the resin jacket member and the metal inner cylinder member provided in the vicinity of the side wall can be separated from each other. The adhering adhesive can prevent the infiltration of water and the like.

As described in claim 2 of the present invention, the concave portion is provided with irregularities for increasing the contact surface area with the adhesive.

As a result, the adhesiveness of the adhesive for adhering the resin jacket member and the metal inner cylinder member can be improved due to the increase in the contact surface area due to the unevenness.

According to claim 3 of the present invention, the adhesive includes
The resin material used for the resin mantle member is kneaded.

Thus, before the metal outer frame member is covered with the resin outer cover member formed over the entire outer peripheral surface of the metal outer frame member and attached to the metal inner tubular member,
It is possible to reduce the amount of wasteful use of the adhesive applied to the recess formed in the metal inner cylinder.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the fuel injection valve of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing a schematic configuration of a fuel injection valve according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a main part according to the present embodiment in FIG. 1, in which the resin jacket member covers the entire circumference of the metal outer frame member and is attached to the metal inner cylinder member. FIG. 3 is a schematic cross-sectional view showing a state in which the metal outer frame member and the metal inner cylinder member are joined together.

As shown in FIG. 1, the fuel injection valve 1 of the present embodiment is used for an internal combustion engine, particularly a gasoline engine,
Fuel is injected into an internal combustion engine. This fuel injection valve 1
Is a substantially cylindrical shape, and has a valve body 29 as a valve portion B,
And a valve member (hereinafter referred to as a nozzle needle) 26,
A coil 31 wound around a spool 30 as an electromagnetic drive unit S, a metal inner cylinder member 14 forming a magnetic circuit in which a magnetic flux due to an electromagnetic force generated by energizing the coil 31 flows, a metal outer frame member 23, and suction by this magnetic flux. A movable body (hereinafter referred to as an armature) 25 that is movable in the axial direction on the nozzle needle 26 side by force, and the armature so that the nozzle needle 26 abuts the valve body 29 and closes when the coil 31 is not energized. And a compression spring 24 for urging 25 toward the valve body.

First, the valve body 29 as the valve portion B, the nozzle needle 26 and the like will be described below.

The valve body 29 is fixed to the inner wall of the metal inner cylinder member 14 by laser welding. Specifically, as shown in FIG. 1, the valve body 29 can be press-fitted or inserted into the magnetic cylindrical portion 14c of the metal inner cylindrical member 14. The valve body 29 inserted in the inner wall of the magnetic cylinder member 14c is
As shown in FIG. 1, the valve body 29 and the cylindrical member 1 are welded from the outer peripheral side of the magnetic cylindrical portion 14c by welding along the entire outer periphery.
The heat welded portion 100 for welding 4 is formed in an annular shape. The nozzle needle 2 is provided on the inner peripheral side of the valve body 29.
A valve seat 29a is formed on which 6 abuts and separates.

That is, the valve body 29 has a bottom wall portion 29 having a valve seat 29a with which the nozzle needle 26 abuts and separates.
b and the metal inner tubular member 1 that is erected from the peripheral edge of the bottom wall portion 29b.
4 and the side wall portion 29h forming the heat-welded portion 100 between them.

As shown in FIG. 1, a fuel passage for fuel to be injected into the internal combustion engine is formed on the inner peripheral side of the valve body 29, and from the downstream side of the internal combustion engine side toward the upstream side of the fuel,
A conical inclined surface 29a serving as a valve seat, a cylindrical wall surface 29d slidably supporting the nozzle needle 26, and a conical inclined surface 29e are sequentially formed. This conical inclined surface or valve seat 29
a is contracted in the fuel injection direction, and an abutting portion 26c of a nozzle needle 26, which will be described later, abuts and separates from the abutting portion 26a.
c and the valve seat are arranged so that they can be seated. This allows
So-called valve opening and closing as the valve section B for communicating and shutting off the fuel to be injected can be performed. Also, the cylindrical wall surface 29
Reference numeral d denotes a needle support hole for slidably supporting the nozzle needle 26, and a fuel passage between the nozzle support 26 and an outer peripheral cutout 26f of a cylindrical protrusion 26a of the nozzle needle 26, which will be described later. . The conical slope surface 29e has a diameter that increases toward the upstream side of the fuel.

The nozzle needle 26 as a valve member is formed so as to slidably be supported by a valve body 29 (specifically, a cylindrical wall surface 29d) and a fuel downstream side of the cylindrical protrusion 26a. It is configured to include a bottomed tubular body 26b and a shaft portion 26d that is formed on the fuel upstream side of the cylindrical protruding portion 26a and that engages with the armature 25. The cylindrical protruding portion 26a has a substantially annular shape, and the outer periphery thereof slides on the cylindrical wall surface 29d. On the outer peripheral side of the cylindrical protruding portion 26a, a substantially annular cylindrical protruding portion 2 is provided so that the upstream fuel of the cylindrical protruding portion 26a flows to the valve seat 29a arranged on the downstream side.
An outer peripheral side notch 26f is formed to remove 6a in an arc shape. Further, a valve seat 29 is provided at the tip of the bottomed tubular body 26b.
An abutting portion 26c capable of abutting and separating from a is formed.

The injection hole plate 28 is formed in a thin plate shape on the tip side of the fuel injection valve 1, and a plurality of injection holes 28a are formed in the central portion. This injection hole 28a determines the injection direction based on the injection hole axis line and the injection hole arrangement, etc., and the fuel injection amount injected from the injection hole depending on the opening area of the injection hole and the valve opening period of the valve portion B by the electromagnetic drive unit S described later. Can be measured.

Next, the coil 31 as the electromagnetic drive section S,
Metal inner cylinder member 14, metal outer frame member 23, armature 2
5, the compression spring 24 and the like will be described below. It should be noted that the electromagnetic drive unit S may be one that opens and closes the valve unit B of the fuel injection valve 1 by energizing.

As shown in FIG. 1, the coil 31 is wound around the outer circumference of a spool 30 made of resin.
A terminal 12 that is electrically connected is provided at one end of the terminal 1. The spool 30 is mounted on the outer periphery of the metal inner tubular member 14 described below, and also protrudes from the outer wall of the resin mold 13 as the resin outer jacket member formed on the outer periphery of the metal inner tubular member 14. A connector portion 16 is provided, and the terminal 12 is embedded in the connector portion 16. The coil 31 and the spool 30 are
A drive coil C that generates an electromagnetic force when energized is configured.

The inner metal tubular member 14 is a pipe material having a magnetic portion and a non-magnetic portion, and is made of, for example, a composite magnetic material. By heating a part of the inner metal tubular member 14 to make it non-magnetic, the inner metal tubular member 14 shown in FIG. 1 is moved toward the upstream from the lower fuel injection side to the magnetic tubular portion 14c and the non-magnetic tubular portion. 14b and the magnetic cylindrical portion 14a are formed in this order. The inner cylindrical metal member 14 is joined to the magnetic cylindrical portion 14c, the non-magnetic cylindrical portion 14b, and the magnetic cylindrical portion 14a by welding or the like.
May be formed.

An armature accommodating hole 14e is provided on the inner circumference of the metal inner cylinder member 14, and the nonmagnetic cylinder portion 14 is formed.
An armature 25, which will be described later, is housed in the vicinity of the boundary between b and the magnetic cylindrical portion 14c.

Further, the metal inner cylinder member 1 forming a magnetic circuit in which a magnetic flux due to an electromagnetic force generated by energizing the coil 31 flows.
A metal outer frame member 2 is provided on the outer periphery of the metal outer frame 4 with the drive coil C interposed therebetween.
3, a resin mold 13 is provided.

More specifically, the metal outer frame member 2 made of a magnetic material.
3 covers the outer circumference of the coil 13 as the drive coil C, and the metal outer frame member 23 is in contact with the outer circumference of the metal inner cylinder member 14, and together with the metal inner cylinder member 14, the coil 3
1 forms another part of the magnetic circuit in which a magnetic flux due to an electromagnetic force generated by energizing 1 flows.

More specifically, as shown in FIG. 1, the metal outer frame member 23 is composed of, for example, two metal plates 23a and 23b, and one end of each of the metal plates 23a and 23b is a magnetic member of the metal inner tubular member 14. It is provided so as to be in contact with the outer circumference of the tubular portion 14a and the other end on the lower side to be in contact with the outer circumference of the magnetic tubular portion 14c.

Resin mold 13 as a resin jacket member
As shown in FIG. 1, so as to cover the entire circumference of the metal outer frame member 23 and adhere to the metal inner tubular member 14,
It is connected to the outer metal frame member 23 and the inner metal tube member 14.

As a result, the magnetic flux generated by the electromagnetic force generated by energizing the coil 31 causes the magnetic cylinder portion 14a, the suction portion 22 of the magnetic cylinder portion 14a, which will be described later, the armature 25, magnetic cylinder portion 14c, and the metal outer frame member, which will be described later. A magnetic circuit that flows in the order of 23 is configured.

As shown in FIG. 1, the inner metal cylinder member 14 is provided with a suction portion 22 capable of regulating the maximum axial movement of the armature 25. The suction portion 22 is magnetized by energization. Armature 25 by the magnetic flux of the circuit
A suction force is generated to move the shaft in the axial direction.

The armature 25 is a cylindrical body made of a ferromagnetic material such as magnetic stainless steel, and has a nozzle needle 2
It is fixed at 6. As a result, when the coil 31 is energized, the magnetic flux generated by the electromagnetic force generated in the coil 31 acts on the armature 25 via the suction portion 22, so that the nozzle needle 26 and the suction portion 2 together with the armature 25.
It is movable in the axial direction on the second side, that is, in the direction away from the valve seat 29a. The internal space 25 of the armature 25
e is configured to communicate with the internal fuel passage formed in the armature housing hole 14e of the metal inner tubular member 14.

The compression spring 24 is sandwiched between the end face of the adjusting pipe 21 arranged on the inner circumference of the suction portion 22 and the spring seat 25c which is a step portion forming the internal space 25e of the armature 25. , When the coil 31 is not energized, the nozzle needle 26 fixed to the armature 25 is brought into contact with the valve body 29 (specifically, the contact portion 26c is brought into contact with the valve seat 29a) to close the armature. 25 is urged to the valve body 29 side with a predetermined urging force. The adjusting pipe 21 is press-fitted and fixed to the inner circumference of the suction member 22, and the biasing force of the compression spring 24 can be adjusted to a predetermined biasing force by the amount of press-fitting of the adjusting pipe 21.

As shown in FIG. 1, the spacer 27 is sandwiched in the axial direction between the side wall portion 29h of the body 29 and the inner metal tubular member 14, and the axial thickness of the spacer 27 is equal to that of the metal. The maximum axial movement amount of the armature 25 with respect to the suction portion 22 of the inner cylinder member 14 can be adjusted to be a predetermined amount (in other words, the air gap between the suction portion 22 and the armature 25 can be adjusted to a predetermined amount. ).

A valve body 29 is housed on the fuel injection side of the metal inner cylinder member 14. On the other hand, a filter 11 as shown in FIG. 1 is attached above the inner metal tubular member 14, and this filter 11 removes foreign matters contained in the fuel flowing from the fuel upstream of the fuel injection valve 1. It is possible.

Here, the fuel injection valve 1 having the above-mentioned structure
The operation of will be described below. Electromagnetic drive coil 31
When electricity is applied to the coil 31, an electromagnetic force is generated in the coil 31. At this time, in the metal outer frame member 23, the metal inner cylinder member 14 (specifically, the suction portion 22) and the armature 25 that form the magnetic circuit, a suction force for sucking the armature 25 is generated in the suction portion 22. As a result, the nozzle needle 26 fixed to the armature 25 moves into the valve seat 29 of the valve body 29.
Separate from a. Therefore, the valve body 29 and the nozzle needle 26 are opened, and the fuel flowing from the upstream side of the fuel injection valve 9 is injected into the internal combustion engine through the injection hole 28a.

However, the structure of the fuel injection valve 1 described above is generally one in which different members such as a resin material and a metal material are integrally fixed by insert molding or the like, and thermal expansion of the resin material and the metal material is performed. There is a possibility that a gap is likely to be formed in the abutting portion of the different members due to the thermal strain caused by the difference of.

That is, the metal inner cylinder member 14 for accommodating the armature 25 and the nozzle needle 26 so as to be reciprocally movable.
And a metal outer frame member 23 sandwiching the drive coil C (specifically, the coil 31 and the spool 30) on the outer periphery of the metal inner tubular member 14 on the outer peripheral surface of the metal outer frame member 23 by the resin mold 13 of the resin outer cover member. By covering the entire circumference and covering the inner metal tube member 14, the driving coil C
In the magnetic circuit operated by the above, there is a possibility that a gap may be formed between the resin outer jacket member 13 adhered to the metal inner cylinder member 14 and the metal inner cylinder member 14 due to thermal strain. If water or the like enters this gap, the internal members such as the drive coil C may be corroded, and in some cases, the function of the drive coil C or the like may be degraded.

(Main parts of the present embodiment and detailed description thereof)
Therefore, in the embodiment of the present invention, by providing the following features, it is possible to suppress the generation of a gap caused by thermal strain due to the difference in thermal expansion between the resin material and the metal material, and to generate a gap. Provided is a fuel injection valve 1 capable of preventing the intrusion of water or the like that causes the functional deterioration of the drive coil C or the like even if it has happened.
That is, in the fuel injection valve 1 including the valve body 29 as a valve portion and the electromagnetic drive portion S mounted and fixed to the outer periphery of the metal inner tubular member 14 fixed to the valve body 29, the drive as the electromagnetic drive portion S is performed. A fuel injection valve in which the valve portion B and the electromagnetic drive portion S can be adhered and fixed airtightly by the metal outer frame member 23 forming a part of the magnetic circuit operated by the coil C and the resin outer jacket member 13 covering the metal inner tubular member 14. I will provide a.

First, as shown in FIGS. 1 and 2, the tip of the resin outer jacket member 13 of resin material (hereinafter referred to as the outer jacket tip) is formed in an annular shape on the outer circumference of the metal inner tubular member 14. It is attached to the annular step portion 14h.

As a result, the metal inner cylinder member 14 and the resin outer jacket member 13 can be hermetically adhered to each other.

Moreover, by covering the entire circumference of the side wall of the annular step portion 14h formed in the annular shape with the resin outer jacket member 13, the resin outer jacket member 13 can cover the entire outer circumference of the metal outer member 23. Therefore, for example, even if a gap is formed between the metal outer frame member 23 and the resin outer jacket member 13, the airtight leak is formed at one place where the tip portion of the resin outer jacket member 13 and the side wall of the annular stepped portion 14h come into contact with each other. Possible sites can be limited.

Next, as shown in FIGS. 1 and 2, an adhesive 50 for bonding the inner metal tube member 14 and the resin outer jacket member 13 together.
A concave portion 14j filled with is provided near the side wall of the annular step portion 14h.

As a result, the resin outer jacket member (specifically, the tip of the outer shell) adhered to the inner metal tube member 14 and the outer periphery of the inner metal tube member 14 (specifically, the recess 14j) are hermetically adhered by the adhesive 50. can do. Therefore, it is possible to improve the joining force for making the outer tip portion and the outer circumference of the metal inner tubular member airtight.

Therefore, even if a gap is generated between the tip of the outer jacket of the resin outer jacket member 13 and the side wall of the annular stepped portion 14h of the inner metal tubular member 14 due to thermal strain, the bonding provided near the side wall. The agent 50 can reliably prevent the intrusion of water and the like.

(Modification) As a first modification, as shown in FIG. 3, the adhesive 5 is applied to the recess 14j filled with the adhesive 50 for bonding the metal inner tubular member 14 and the resin jacket member 13.
The unevenness 14 jp that increases the contact area with 0 is provided.

FIG. 3 is a sectional view showing the main part of the modified example, in which the resin jacket member covers the entire circumference of the metal outer frame member and is attached to the metal inner cylinder member. It is a typical sectional view showing the state where it is connected to the metallic outer frame member and the metallic inner cylinder member.

As a result, the adhesiveness of the adhesive 50 for adhering the resin outer jacket member 13 and the metal inner tubular member 14 to the unevenness 1
It can be improved by increasing the contact surface area by 4 jp.
Therefore, the holding force of the adhesive 50 that hermetically seals the resin outer jacket member 13 and the inner metal tube member 14 can be improved.

As a second modification, the adhesive 50 contains:
The resin material used for the resin mold 13 of the resin mantle member is kneaded.

As a result, the resin inner jacket member 13 formed by resin molding or the like covers the entire outer peripheral surface of the metal outer frame member 23 and before the metal inner tube member 14 is covered with the metal inner tube member 14. It is possible to reduce the amount of wasteful use of the adhesive 50 applied to the concave portion 14j formed in 14.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a fuel injection valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a main part according to the present embodiment in FIG. 1, in which a resin jacket member covers the entire circumference of a metal outer frame member and is attached to a metal inner cylinder member. FIG. 3 is a schematic cross-sectional view showing a state in which the metal outer frame member and the metal inner cylinder member are joined together.

FIG. 3 is a cross-sectional view showing a main part of a modified example, in which the resin outer jacket member covers the entire circumference of the metal outer frame member and is attached to the inner metal tube member, It is a typical sectional view showing the state where it has joined with a metal inner cylinder member.

[Explanation of symbols]

1 Fuel Injection Valve 11 Filter 14 Metal Inner Cylinder Member 14a, 14b, 14c Magnetic Cylinder, Non-Magnetic Cylinder, Magnetic Cylinder 14h Circular Step 14j Recess 14jp Filling Resin Material 50 Concavo-convex provided in Recess 22 Metal Suction part 23 of the cylindrical member 14 Metal outer frame member 24 Compression spring 25 Armature (movable body) 26 Nozzle needle (valve member) 26c Abutting part 27 Spacer 28 Injection hole plate 28a Injection hole 29 Valve body 29a Valve seat 29d Cylindrical wall surface ( Needle support hole) 29b Bottom wall portion 29h Side wall portion 31 Coil 30 Spool 100 Welded portion B Valve portion S Electromagnetic drive portion C Drive coil composed of coil 31 and spool 30

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toyoji Nishiwaki             1-1, Showa-cho, Kariya city, Aichi stock market             Inside the company DENSO F term (reference) 3G066 AA01 AD07 BA36 BA50 BA54                       CC01 CD10 CD17 CE22

Claims (3)

[Claims] 1. A metal inner cylinder which houses a movable body and a valve member engaged with the movable body so as to be capable of reciprocating in the axial direction and constitutes a part of a magnetic circuit for driving the movable body. A member, a drive coil for operating the magnetic circuit, and a metal inner cylinder disposed on the outer periphery of the metal inner cylinder member with the drive coil interposed therebetween, and the tip end portion of the metal inner cylinder forming another part of the magnetic circuit. A metal outer frame member that is in contact with the member; and a resin outer jacket member that covers the outer peripheral surface of the metal outer frame member over the entire circumference and is adhered to the metal inner tubular member, the outer jacket tip portion of the resin outer jacket member Is attached to a side wall of an annular stepped portion formed on the outer peripheral side of the metal inner tubular member, and the resin outer cover member and the metal inner tubular member are provided in the vicinity of the side wall of the metal inner tubular member. Is provided with a recess filled with an adhesive for bonding Fuel injection valve. 2. The fuel injection valve according to claim 1, wherein the concave portion is provided with irregularities that increase a contact surface area with the adhesive. 3. The fuel injection valve according to claim 1, wherein the adhesive is kneaded with a resin material used for the resin jacket member.