JPH11210603A - Fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the thinning of an orifice plate while preventing the displacement of a valve seat by fuel pressure and avoiding the lowering of reliability and durability. SOLUTION: A fuel injection valve is provided with a body 1, a valve slat 13 which has a fuel injection nozzle 13a and is inserted into the body 1, an orifice plate 14 which has an injection hole 14a attached on the valve seat 13 and linked with the fuel injection nozzle 13a, and a holder member 30 installed between the body 1 and the valve seat 13 and installs a plastic deformation unit 30a between installation units 12 and 15. This structure enables to use an orifice plate 14 of thin thickness t1 different from the holder member 30 while maintaining the rigidity of the plastic deformation unit 30a of the holder member 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A conventional fuel injection valve includes a body 101 having a substantially cylindrical shape, as shown in a main part sectional view of FIG.
A valve seat 113 having an injection port 113a and inserted into the body 101; and an injection port attached to the valve sheet 113 by laser welding (see reference numeral 112 in FIG. 10) and communicating with the injection port 113a. Stainless steel orifice plate 11 having hole 114a
There is one provided with 4. In addition, the fuel injection valve provided with the orifice plate includes, for example, Japanese Patent Application Laid-Open No. 8-21897.
There is one disclosed in Japanese Patent Application Laid-Open No. 3 (Kokai) No.

Further, on the outer peripheral portion of the orifice plate 114, an annular mounting piece portion 114b bent forward is formed through a bent portion 114c having an L-shaped cross section. The fitting piece 114b is attached to the inner peripheral surface of the body 101 by laser welding (see reference numeral 115 in FIG. 10) after the valve seat 113 is inserted into the body 101. As a result, the orifice plate 114 moves the body 101 and the valve seat 11
3 and a bent portion 114c of the orifice plate 114 located between the bridge portions is set as a plastic deformation portion 114b (same as the bent portion). Injection port 1 of the valve seat 113
13 a is opened and closed by a ball valve 123 of the movable body 120.

[0004] The plastic deformation of the bent portion 114c of the orifice plate 114 is utilized to make the body 10
The position of the valve seat 113 with respect to the position 1 is adjusted.
For example, when the valve seat 113 is pushed rearward, the bent portion 114c of the orifice plate 114 is plastically deformed so as to expand the bending angle, and the valve seat 113 is held at a predetermined position by stopping the pushing. Is done.

[0005]

According to the above-described fuel injection valve, when the bent portion 114c of the orifice plate 114 returns and deforms due to the fuel pressure (also referred to as fuel pressure) applied to the valve seat 113, the valve seat 113 is closed.
, The opening / closing stroke of the movable body greatly changes, which may lead to a decrease in durability reliability. Therefore, conventionally, the orifice plate 1
The orifice plate 114 has a thickness T of, for example, 0.18 to
The required rigidity had to be secured by increasing the thickness to 0.2 mm, and it was difficult to make the orifice plate 114 thinner.

In view of the fact that the injection holes 114a of the orifice plate 114 are pressed or punched out, the thinner the thickness T of the orifice plate 114 is,
This is advantageous because the injection hole 114a can be punched with high accuracy, the wear of the cutting edge of the punch is reduced, and the number of press shots is increased. On the other hand, if the thickness T of the orifice plate 114 is too small, the injection holes 11 necessary for giving directivity to the injected fuel are not required.
Since the length 4a cannot be obtained, at least a minimum necessary thickness (for example, about 0.07 to 0.13 mm) is required.

An object of the present invention is to provide a fuel injection valve capable of realizing a thin orifice plate while preventing a displacement of a valve seat due to a fuel pressure and avoiding a decrease in durability reliability. is there.

[0008]

According to a first aspect of the present invention, there is provided a body, a valve seat having a fuel injection port and inserted into the body, a valve seat attached to the valve seat, The fuel injection valve includes an orifice plate having an injection hole communicating with the injection port, and a holder member provided between the body and the valve seat and having a plastic deformation portion between the provided portions. With this configuration, it is possible to prevent the displacement of the valve seat due to the fuel pressure by securing the rigidity of the plastic deformation portion of the holder member. Further, it is possible to use an orifice plate having a different thickness from the holder member. Therefore, it is possible to reduce the thickness of the orifice plate while preventing the displacement of the valve seat due to the fuel pressure and avoiding a decrease in durability reliability.

According to a second aspect of the present invention, there is provided the fuel injection valve according to the first aspect, wherein an orifice plate is sandwiched between the holder member and the valve seat. With this configuration, it is not necessary to attach the orifice plate to the valve seat alone, so that the number of steps for attaching the orifice plate can be reduced.

[0010]

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
The front half of a substantially short cylindrical ring 2 made of a non-magnetic material is press-fitted and welded in the rear end. 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. The core 3 has a bulged portion 3b formed 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 body 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. The connection end 5a of the terminal 5
It is 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.

A valve seat assembly Vs is fitted to the end of the body 1. Valve seat assembly Vs
2 is shown in a partial sectional view in FIG.
2, the valve seat assembly Vs includes a valve seat 13, an orifice plate 14, and a plate holder 3.
It consists of 0. The valve seat 13 has a substantially cylindrical shape with a bottom, and has an injection port 13a on a front end surface thereof.
The orifice plate 14 is provided with the valve seat 1.
3, which is made of a stainless steel circular plate and has a valve seat 13 at its center.
Has a plurality of injection holes 14a communicating with the injection holes 13a. On the outer peripheral portion of the orifice plate 14, an annular fitting piece 14b is bent rearward, and the fitting piece 14b is bent.
b is fitted to the front end of the valve seat 13.
FIG. 9 is a perspective view of the valve seat assembly Vs before assembly.

As shown in FIG. 2, the plate holder 30 is provided on the outer peripheral portion of the front end face of the orifice plate 14, and is formed of a stainless steel annular plate material and has an L-shaped cross section on its outer peripheral portion. An annular attachment piece 30b is formed to be bent forward through the bent portion 30a. The inner peripheral end of the plate holder 30 on the valve seat side is laser-welded to the valve seat 13 with the orifice plate 14 therebetween (see reference numerals 12 in FIG. 2).
It is attached by.

After the valve seat assembly Vs is fitted into the front end of the body 1, the mounting piece 30b of the plate holder 30 is laser welded to the inner peripheral surface of the body 1 (FIG. 2).
See code inside, 15. ). The valve seat 1 with respect to the body 1 is utilized by utilizing the plastic deformation of the bent portion 30a of the plate holder 30.
Position adjustment 3 is performed. Thus, the plate holder 30 is bridged between the body 1 and the valve seat 13, and the bent portion 30a of the plate holder 30 located between the bridged portions (corresponding to the welds 12, 15). Are set as the plastically deformed portions 30a (the same reference numerals are assigned to the bent portions). The injection port 13 a of the valve seat 13 is opened and closed by a ball valve 23 of the movable body 20.

The position of the valve seat 13 with respect to the body 1 is adjusted by utilizing the plastic deformation of the bent portion 30a of the plate holder 30. For example, when the valve seat 13 is pushed backward, the bent portion 30a of the plate holder 30 is plastically deformed so as to expand the bending angle, and the valve seat 13 is held at a predetermined position by stopping the pushing. Is done.

The plate holder 30 has a thickness t ₂ that can secure rigidity such that the bent portion 30 a does not return and deform due to the fuel pressure applied to the valve seat 13. The plate holder 30 corresponds to a holder member in the present invention. In addition, the orifice plate 1
4 is an injection hole 14 necessary for giving directivity to the injected fuel.
and it has a wall thickness t ₁ minimum required to be able to earn the length of a. For example, the wall thickness t ₂ is 0.18~0.2 mm,
The thickness t ₁ is 0.07~0.13 mm. The thickness t ₂ is the thickness T of the conventional orifice plate 114.
(See FIG. 10).

In FIG. 1, a valve spring 16 made of a coil spring is inserted into the core 3, and 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 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 and plate holder 30 are SUS304.

The operation of the fuel injection valve constructed as described above will be described. The fuel supplied from a fuel tank (not shown) under a predetermined pressure 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 energized 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.

According to the above-described fuel injection valve, the displacement of the valve seat 13 due to the fuel pressure can be prevented by securing the rigidity of the plastic deformation portion 30a (see FIG. 2) of the plate holder 30. Further, it is possible to use the orifice plate 14 having a thin thickness t ₁ different from that of the plate holder 30. Therefore, the orifice plate 14 can be made thinner while preventing displacement of the valve seat 13 due to fuel pressure and avoiding a decrease in durability reliability.

Further, since the orifice plate 14 is sandwiched between the plate holder 30 and the valve seat 13, it is not necessary to attach the orifice plate 14 to the valve seat 13 alone, thereby reducing the man-hour for attaching the orifice plate 14. Can be achieved.

The present invention is not limited to the above embodiment, but can be modified without departing from the spirit of the present invention. For example, the plate holder 30 is directly attached to the valve seat 13 without sandwiching the orifice plate 14 between the plate holder 30 and the valve seat 13, and an orifice having an outer diameter smaller than the inner diameter of the plate holder 30 is provided. The plate 14 can be independently attached to the front end portion of the valve seat 13 exposed in the plate holder 30. Further, the orifice plate 14 and the plate holder 30 can be formed of different materials.

[0033]

According to the fuel injection valve of the present invention, the thickness of the orifice plate can be reduced while preventing the positional displacement of the valve seat due to the fuel pressure and avoiding the reduction of the durability reliability.

[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 sectional view of a main part 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 perspective view of a valve seat assembly.

FIG. 10 is a sectional view of a main part showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body 13 Valve seat 13a Injection port 14 Orifice plate 14a Injection hole 30 Plate holder (holder member) 30a Bent part (plastic deformation part)

Claims (2)

[Claims] 1. An orifice plate having a body, a valve seat having a fuel injection port and fitted into the body, an orifice plate having an injection hole attached to the valve seat and communicating with the injection port, and And a holder member having a plastically deformed portion provided between the mounting portion and the valve seat. 2. The fuel injection valve according to claim 1, wherein an orifice plate is sandwiched between the holder member and the valve seat.