JPH11294293A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the inside diameter change of a ring body connected to the connecting end part of a body by press-in and welding, and dispense with the post-machining or post-treatment of the ring body which was required in the past. SOLUTION: This fuel injection valve is provided with a substantially cylindrical body 1 and a substantially cylindrical ring body 2 having a press-in end 2a to be pressed into the connecting end 1a of the body 1 and fixed by welding 27. When the strength of the connecting end 1a of the body 1 is Bs, and the strength of the press-in end 2a of the ring body 2 is Rs, the both have a relation of Bs<Rs. In the press-in and welding of the press-in end 2a of the ring body 2 to the connecting end 1a of the body l, the connecting end 1a of the body 1 is deformed so as to extend the diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a fuel injection valve.

[0002]

2. Description of the Related Art In a conventional fuel injection valve, as shown in a sectional view of a main part in FIG. 11, a substantially cylindrical body 101 forming a magnetic path and a connection end 101a of the body 101 are press-fitted. A non-magnetic short cylindrical ring member 102 having a press-fit end portion 102a fixed by laser welding (weld portions are denoted by reference numerals 127) and the like;
And an armature 122 that is slidably inserted into the armature 2 to form a magnetic path (for example, see
-96264). The conventional ring body 102 has a simple cylindrical shape, and has a connection end 10 of the body 101.
The thickness ta was about half that of the thickness Ta of 1a. The strength of the connection end 101a of the body 101 is Bs, and the strength of the press-fit end 102a of the ring body 102 is Rs.
In this case, Bs> Rs. The armature 122 is attracted to the core 103 forming a magnetic path by energizing a solenoid coil (not shown).

[0003]

According to the conventional fuel injection valve, when the press-fit end 102a of the ring 102 is press-fitted and welded to the connection end 101a of the body 101, the press-fit end 102a of the ring 102 is reduced in diameter. The deformation causes a change in the inner diameter of the press-fit end portion 102a. Further, since the inner peripheral surface of the ring body 102 functions as a guide surface of the armature 122, it is necessary to ensure accuracy. Therefore, post-processing such as cutting the inner peripheral surface of the ring body 102 is required, and post-processing for removing burrs generated by the cutting is also required.

SUMMARY OF THE INVENTION An object of the present invention is to prevent a change in the inner diameter of a ring body connected to a connection end of a body by press-fitting and welding, thereby eliminating the need for post-processing or post-processing of a conventionally required ring body. Is to provide.

[0005]

According to a first aspect of the present invention, there is provided a vehicle having a substantially cylindrical body and a substantially press-fit end which is press-fitted to a connection end of the body and fixed by welding. A ring having a cylindrical shape, wherein the strength of the connection end of the body is Bs, and the strength of the press-fit end of the ring is Rs, and the relationship of Bs <Rs is set. With this configuration, at the time of press-fitting and welding the press-fit end of the ring body to the connection end of the body,
By expanding the diameter of the connection end of the body, it is possible to prevent a change in the inner diameter of the ring body, thereby making it unnecessary to perform post-processing or post-processing of the ring body, which is conventionally required.

According to a second aspect of the present invention, there is provided the fuel injection valve according to the first aspect, wherein a press-fitting flange is formed at a press-fit end of the ring body so as to protrude radially outward. With this configuration, it is possible to increase the strength of the press-fit end without increasing the outer diameter of the main body except the press-fit end of the ring body.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. First, the outline of the fuel injection valve will be described, and then the main part will be described in detail. FIG. 1 is a sectional view of a fuel injection valve used in a vehicle engine. For convenience, the left side in FIG. 1 is referred to as the front of the fuel injection valve, and the right side is similarly referred to as the rear.

In FIG. 1, the body 1 of the fuel injection valve is
It is formed in a substantially cylindrical shape by a ferromagnetic material. Body 1
In the rear end portion, a front half portion (corresponding to a press-fit end portion described later) of a substantially short cylindrical ring body 2 made of a nonmagnetic material is welded after press-fitting. A front end of a hollow shaft-shaped core 3 made of a ferromagnetic material is welded into the rear half of the ring body 2 after press-fitting. At a substantially central portion in the axial direction of the core 3, a flange 3a protruding radially outward is formed. Core 3
Is formed with a bulging portion 3b located on the rear side of the flange 3a. The bulging portion 3b is formed with an outer diameter slightly larger than the outer diameter of a portion behind it.

A bobbin 4 made of an electrically insulating material such as a synthetic resin is molded around the connection between the ring 2 and the core 3. The bobbin 4 is wound with a solenoid coil 6. At the rear end of the bobbin 4, a terminal mounting portion 4a is provided. The connection end portion 5a of the terminal 5 is attached to the terminal attachment portion 4a by press fitting. Connection end 5a of the terminal 5
Are electrically connected to the solenoid coil 6.

An outer peripheral portion of the solenoid coil 6 is provided with an extension piece 7a of an outer magnetic path forming member 7 made of a ferromagnetic material described below.
Is partially surrounded by FIG. 3 is a rear view of the outer magnetic path forming member 7, FIG. 4 is a bottom view thereof, and FIG. 5 is a sectional view taken along line VV of FIG. FIG. 3-
As shown in FIG. 5, the outer magnetic path forming member 7 has an end plate portion 7b having a substantially oval shape and having a circular mounting hole 8 at the center, and front end portions from the upper and lower ends of the end plate portion 7b. And a pair of two extension pieces 7a each having an arc-shaped cross section and extending toward. The mounting hole 8 has a diameter slightly smaller than the outer diameter of the bulging portion 3b of the core 3. The outer magnetic path forming member 7 is an integrally molded product formed by deep drawing one sheet of a ferromagnetic metal material. The mounting hole 8 of the end plate portion 7b is formed by punching.

As shown in FIG. 1, the outer magnetic path forming member 7 fits the mounting hole 8 into the rear end of the core 3 and press-fits it into the bulging portion 3b of the core 3, and also has an end plate portion. 7
b is abutted against the flange 3a of the core 3 from the axial direction, so that the core 3 is attached to the core 3 while being positioned. At the same time as this attaching work, the outer magnetic path forming member 7
The rear end of the body 1 is joined to the front end of the extension piece 7a by welding.

In FIG. 1, resin molding is applied to the periphery from the rear half of the body 1 to the rear end of the core 3 so as to surround that part. By this resin molding, a connector 9 surrounding the terminal 5 is formed. The connector 9 is connected to a power supply connector of an electronic control unit (not shown), and energizes and releases the solenoid coil 6 by receiving an input from the electronic control unit.

A rear end of a movable body 20 described below is slidably fitted into a connection portion between the body 1 and the ring body 2. 6 is a side view of the movable body 20, FIG. 7 is a sectional view taken along line VII-VII of FIG. 6, and FIG.
FIG. 8 is a cross-sectional view taken along the line I-VIII.
As shown in FIGS. 6 to 8, the movable body 20 is composed of an armature 22 made of a ferromagnetic material having a hollow shaft shape, and a ball valve 23 attached so as to close the opening at the tip of the armature 22. Have been. The armature 22 has a pair of lateral holes 22a formed in the side wall of the distal end. The armature 22 has a hollow portion and a lateral hole 22a.
The fuel passage 24 (see FIG. 8) is formed by the holes.

The rear end of the armature 22 has a large-diameter cylindrical portion 22A having an outer diameter larger than the outer diameter of the front portion.
Are integrally formed. As shown in FIG. 8, a stepped surface 25 is formed on an inner peripheral surface of a connection portion between the large-diameter cylindrical portion 22 </ b> A of the armature 22 and a small-diameter cylindrical portion (reference numeral omitted) ahead of the large-diameter cylindrical portion.

The armature 22 is integrally formed by metal injection molding. As is well known, the molding process of metal injection molding includes a kneading process of kneading a fine powder of a metal material and a binder, a molding process of molding the kneaded material with an injection molding machine, and a molding process using a solvent in a degreasing furnace. It comprises a liquid degreasing step of removing the binder from the body and a sintering step of sintering the degreased compact in a sintering furnace. As the metal material in this case, a ferromagnetic material, for example, electromagnetic SUS, Permalloy, or the like is used.

The movable body 20 is arranged in the body 1 as follows. That is, as shown in FIG. 1, the large-diameter cylindrical portion 22 </ b> A of the armature 22 is slidably fitted in a connection portion between the body 1 and the ring body 2. The armature 22 is connected to the solenoid coil 6
Is attracted to the core 3 by being subjected to a suction action when the power is supplied. Further, an injection port 13 is provided at the tip of the body 1.
a bottomed cylindrical valve seat 13 having a at its front end face
Is inserted. The injection nozzle section including the valve seat 13 is shown in a partial cross-sectional view in FIG.

In FIG. 2, an orifice plate 14 is welded to the front end surface of the valve seat 13 by laser welding or the like (the reference numeral 12 is given in FIG. 2). The orifice plate 14 is made of a circular plate having a plurality of injection holes 14a at the center. In addition, an annular mounting piece 14 b bent forward is formed on the outer peripheral portion of the orifice plate 14. After the position of the valve seat 13 is adjusted after the valve seat 13 is inserted into the body 1, the mounting piece 14b of the orifice plate 14 is welded to the inner peripheral surface of the body 1 by laser welding or the like (reference numerals in FIG. 2). 15). Thereby, the valve seat 13 is fixed to the body 1 at a predetermined position. As shown in FIG. 1, the valve seat 13 and the core 3
The movable body 20 slides in the axial direction between the movable body 20 and the ejection port 13 a of the valve seat 13 is opened and closed by the ball valve 23 of the movable body 20.

In FIG. 1, a valve spring 16 made of a coil spring is inserted into the core 3, and then a spring pin 17 having a C-shaped cross section is press-fitted. The front end portion of the valve spring 16 is inserted into the large-diameter cylindrical portion 22A of the armature 22 of the movable body 20, and the front end surface of the valve spring 16 has a stepped surface 25 of the armature 22.
(See FIG. 8). The valve spring 16 always biases the movable body 20 in the valve closing direction.

A series of fuel passages 18 are formed by the internal space between the rear end opening of the core 3 and the injection port 13a of the valve seat 13. The fuel passage 18 also includes a fuel passage 24 of the movable body 20. A strainer 19 is attached to the rear end of the core 3 by press fitting. Further, at the time of resin molding of the connector 9, an annular groove (reference numeral 10 in FIG. 1) is formed on the outer peripheral surface of the rear end of the core 3. An O-ring 11 is fitted in the annular groove 10. The O-ring 11 acts as a seal between the core 3 and a delivery pipe (not shown) connected to and connected to the core 3.

It should be noted that an example of a specific material of the main components of the fuel injection valve is described below.
S, ring body 2 is SUS304, core 3 is electromagnetic SUS,
The outer magnetic path forming member 7 is electromagnetic SUS, the armature 22 is electromagnetic SUS or permalloy, and the valve seat 13 is S
US440C, orifice plate 14 is SUS304
It is.

The operation of the fuel injection valve constructed as described above will be described. The fuel supplied under a predetermined pressure from a fuel tank (not shown) is filtered by a strainer 19 and then filtered through a fuel passage 18. Through the valve seat 13. However, movable body 2
Since the zero ball valve 23 keeps the injection port 13a of the valve seat 13 closed by the elasticity of the valve spring 16, fuel injection does not occur from this injection port 13a.

Here, when the solenoid coil 6 is turned on by the input of an electric signal from the electronic control unit, a magnetic path passing through the core 3, the armature 22 of the movable body 20, the body 1, and the outer magnetic path forming member 7 is formed. As a result, the movable body 20 slides or retracts in the axial direction by the suction action of the core 3 due to this. As a result, the ball valve 2 of the movable body 20
3 opens the injection port 13a of the valve seat 13, from which fuel is injected. The injected fuel is further injected through an injection hole 14a of the orifice plate 14 (see FIG. 2). Then, the electric signal to the solenoid coil 6 is turned off, and the core 3 acting on the armature 22 is turned off.
Is released, the movable body 20 is advanced by the elasticity of the valve spring 16, whereby the ball valve 23 of the movable body 20 is kept in the state where the injection port 13a is closed again. Fuel injection stops.

Next, the configuration of the main part will be described in detail. In the fuel injection valve, the structure for attaching the ring body 2 to the body 1 is configured as follows. In the cross-sectional view of the main part and the exploded perspective view of FIG. 9 in which the main part is partially broken, the connection end part (reference numeral 1a) of the body 1 is provided with the press-fit end part (reference numeral 2a) of the ring body 2. ) Is press-fitted and fixed by laser welding (labeled 27 in FIG. 9). Inner peripheral stepped surface 1b of connection end 1a of body 1
, The end face of the ring body 2 abuts. In addition, the ring body 2
The front end of the core 3 is press-fitted and fixed by laser welding (reference numeral 28 in FIG. 9).

[0024] Conventionally connecting end portion 1a of the body 1 are also to large diameter outer diameter as compared to (see FIG. 11), thereby meat main portion thickness T ₁ is the body 1 of the connecting end portion 1a Thickness T ₂
The thickness is reduced to about 1/5 as compared with the above. Also, body 1
Thickness T ₁ of the connecting end portion 1a of the conventional wall thickness Ta (FIG. 11
) Is about 1/3 of that of the above.

Further, the press-fit end portion 2a of the ring body 2 is press-fitted flange 2a ₁ projecting radially outward is formed. The formation of the press-fitting flange 2a _1, are similarly to the large outer diameter and the diameter than the press-fitting ends 2a of the ring body 2 is conventional (see FIG. 11), thereby the thickness t of the press-fit end portion 2a ₁ is thickened to approximately 2.5-3 times that of the wall thickness t ₂ of the main body portion of the ring member 2 (code, denoted by 2b.). The thickness t1 of the press-fit end 2a of the ring body 2
Has a thickness of about 2.5 to 2.5 in comparison with the conventional thickness ta (see FIG. 11).
It is three times thicker. FIG. 10 is an exploded perspective view of a main part of the body 1 and the ring body 2 which is partially broken away.

The strength of the connection end 1a of the body 1 is represented by B
s, when the strength of the press-fit end 2a of the ring body 2 is Rs, the thickness of the connection end 1a of the body 1 and the increase in the thickness of the press-fit end 2a of the ring body 2 allow Bs <Rs. Set in a relationship.

According to the above-described fuel injection valve, the strength Bs of the connection end 1a of the body 1 and the strength Rs of the press-fit end 2a of the ring body 2 are set to satisfy the relationship of Bs <Rs. Therefore, when the press-fit end 2a of the ring body 2 is press-fitted and welded to the connection end 1a of the body 1, the inner diameter of the ring body 2 can be prevented from being changed by expanding and deforming the connection end 1a of the body 1. This makes it possible to eliminate the need for post-processing and post-processing of the ring body 2 which is conventionally required.

Further, since it is obtained by forming a press-fitting flange 2a ₁ projecting radially outwardly pressed edge portions 2a of the ring body 2, without the large outer diameter of the main portion 2b of the ring body 2, The strength of the press-fit end 2a can be increased. This is useful for avoiding a reduction in the space for housing the solenoid coil 6 disposed around the main body 2b.

The present invention is not limited to the above embodiment, but can be modified without departing from the scope of the present invention. For example, the relationship of Bs <Rs can be set by selecting the materials of the body 1 and the ring 2. In addition, by reducing the outer diameter of the connection end 1a of the body 1 and / or reducing the diameter (inner diameter) of the press-fit end 2a of the ring body 2, the Bs <
The relationship of Rs can be set.

[0030]

According to the fuel injection valve of the present invention, the inner diameter of the ring body connected to the connection end of the body by press-fitting and welding is prevented from changing, and the post-processing and post-processing required for the conventionally required ring body are prevented. It can be unnecessary.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a fuel injection valve according to one embodiment.

FIG. 2 is a partial cross-sectional view of an injection nozzle portion of a fuel injection valve.

FIG. 3 is a rear view of the outer magnetic path forming member.

FIG. 4 is a bottom view of the outer magnetic path forming member.

FIG. 5 is a sectional view taken along line VV of FIG. 3;

FIG. 6 is a side view of the movable body.

FIG. 7 is a sectional view taken along line VII-VII of FIG. 6;

FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7;

FIG. 9 is a sectional view of a main part.

FIG. 10 is an exploded perspective view showing a main part partially broken away.

FIG. 11 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Body 1a Connection end 2 Ring body 2a Press-fit end 2a ₁ Press-fit end

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 61/18 360 F02M 61/18 360B

Claims (2)

[Claims] 1. A substantially cylindrical body having a substantially cylindrical body, and a substantially cylindrical ring body having a press-fit end fixed to the connection end of the body by press-fitting, the connection end of the body being provided. Where Bs is the strength of Bs and Rs is the strength of the press-fit end of the ring body, wherein Bs <Rs. 2. The fuel injection valve according to claim 1, wherein a press-fitting flange protruding outward in the radial direction is formed at a press-fit end of the ring body.