JPH11200980A - Fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the wear due to repetitive contact between a movable body and a contact member and improve the durability and reliability of a fuel injection valve. SOLUTION: This fuel injection valve is provided with a movable body 20 which receives the attractive action due to current carrying to a solenoid coil and slides in the axial direction and a core 3 regulating a slide position of the movable body 20 at the time of slide due to the current carrying to the solenoid coil by mutual contact of opposing faces 3c, 22b opposing on the same axial line. On a rear end face 22b of an armature 22 of the movable body 20, a contact part 22b3 which is positioned on a circumferential line having a smaller diameter D than an outside diameter of the opposing range H in the radial direction in opposition to a front end face 3c of the core 3 and comes into point-contact with the front end face 3c of the core 3 due to the inclination of the movable body 20 is provided.

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 general fuel injection valve has a movable body which slides in an axial direction by being attracted by energization of a solenoid coil, and a sliding position of the movable body which slides when energized by the solenoid coil. And a contact member that is regulated by contact between the opposing surfaces. For example, in the fuel injection valve disclosed in Japanese Patent Application Laid-Open No. 7-153624, a movable element having a valve closing body corresponds to a movable element, and a rear end surface of the movable element corresponds to a surface facing a contact member. The inner pole corresponds to the contact member, and the front end face of the inner pole corresponds to the face facing the mover.

[0003] Each of the facing surfaces of the conventional movable member and abutment member in the fuel injection valve, as shown in the cross sectional view in FIG. 13, both the axis L, the plane 103c that is orthogonal to L _1, 122b Was formed. In addition, a clearance C of, for example, about 50 μm is set between the outer peripheral surface of the movable body 120 and the concentric inner peripheral wall 102 a for guiding the movable body 120 so as to allow the movable body 120 to slide smoothly. Is done. The movable body 120 is
Usually, the elasticity of a spring (not shown) urges the solenoid coil (not shown) in the direction opposite to the sliding direction due to energization.

[0004] Due to the setting of the clearance C and the urging by a spring, as shown in a sectional view of the main part in FIG. And always slide at an inclination angle θ ₁ . Therefore, the movable member 120 and the contact member 1 at the time of sliding by energization of the solenoid coil are connected.
_No. 03 does not make surface contact between the opposing surfaces 112b and 103c but makes point contact at a point P1. Note that FIG similar to FIGS. 13 and 14 as well as FIG. (9, 11, 12), the clearance C, the inclination angle theta _1, etc. are represented with exaggeration.

[0005]

According to the conventional fuel injection valve, the point P1 at which the movable body 120 and the contact member 103 come into point contact with _{each other} is on the outer peripheral edge of the rear end face 122b of the movable body 120, It is in a position far from the axis of the body 120 where the moment acts greatly. Therefore, both 120, 10
At the time of contact (also referred to as contact) of _{No. 3} , a large stress is locally applied to the point P1, and the movable body 120 and the contact member 103 are likely to be worn. When this wear occurs, the movable body 120
The increase in the slide stroke causes a change in the injection flow rate. Further, the movable body 120 and the contact member 1
03 is increased, so that both 120,
The contact force of the contact member 103 at the time of contact increases, and the return timing when the movable body 120 separates from the contact member 103 and returns to the original state is delayed. For this reason, the movable body 12
Abrasion caused by repeated contact between the contact member 103 and the contact member 103 contributes to a decrease in durability and reliability.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel injection valve capable of preventing abrasion due to repeated contact between a movable body and a contact member and improving durability and reliability.

[0007]

According to a first aspect of the present invention, there is provided a movable body which slides in an axial direction by an attraction action by energizing a solenoid coil, and a movable body which slides by energizing the solenoid coil. A contact member that regulates the sliding position of the body by contact between opposing surfaces opposing each other on the same axis, wherein the movable member and the contact member have one of the opposing surfaces. A contact portion that is located on a circumferential line having a diameter smaller than the outer diameter of a radially opposed area facing the other opposed surface and that makes point contact with the other opposed surface due to the inclination of the movable body. . With this configuration, the movable body and the contact member at the time of sliding by energization of the solenoid coil come into contact with each other when the contact portion provided on one of the opposing surfaces makes point contact with the other opposing surface. At this time, since the contact portion is located on a circumferential line having a diameter smaller than the outer diameter of the radially opposed range facing the other facing surface, the contact between the movable body and the contact member is a conventional contact. The position is closer to the axial center than in the case where it is on the outer peripheral edge of the movable body, and the moment is smaller. Therefore, the stress locally applied at the time of contact between the movable body and the contact member is reduced as compared with the related art, so that wear due to repeated contact between the movable body and the contact member can be prevented. Durability and reliability can be improved.

According to a second aspect of the present invention, there is provided the fuel injection valve according to the first aspect, wherein the constituent members forming the opposing surfaces of the movable body and the contact member are members forming magnetic paths, respectively. The surface is formed by a plane perpendicular to the axis and a tapered surface inclined with a taper angle larger than the inclination angle of the movable body with respect to the plane, and the other opposing surface is formed by a plane perpendicular to the axis. With this configuration, the ridge line formed by the flat surface of one of the opposed surfaces and the tapered surface can be easily formed as the contact portion, and the ridge line having a diameter smaller than the outer diameter of the other opposed surface even when the movable body is inclined. Will come into contact with each other. Further, by securing the opposing portions of the opposing surfaces, the reduction of the magnetic path area can be prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment 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, a body 1 of a fuel injection valve is
It is formed in a cylindrical shape by a ferromagnetic material. In the rear end of the body 1, the first half of the ring 2 made of a non-magnetic 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 resin-molded around a connection portion 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. 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 the 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 portion 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. As a result, the rear end surface of the armature 22 of the movable body 20 and the front end surface of the core 3 are opposed on substantially the same axis. 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. At this time, the sliding position of the movable body 20 is regulated by the rear end surface of the armature 22 abutting on the front end surface of the core 3.

At the front end of the body 1, a cylindrical valve seat 13 with a bottom having an injection port 13a at the front end face is provided.
Is inserted. The injection nozzle portion including the valve seat 13 is shown in FIG. In FIG.
The front end face of the valve seat 13 has an orifice plate 1
Reference numeral 4 is welded 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 movable body 20 slides in the axial direction between the valve seat 13 and the core 3, whereby the injection 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 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 configured 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 supplied to 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 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 facing surface between the armature 22 of the movable body 20 and the core 3 is formed as follows. In the cross-sectional view of the main part in FIG. 9, the armature 22 is a constituent member of the movable body 20 that forms a surface (also referred to as a rear end surface, denoted by reference numeral 22 b) facing a front end surface (denoted by reference numeral 3 c) of the core 3. Is equivalent to The core 3 has a surface (front end surface 3c) facing the rear end surface 22b of the armature 22 of the movable body 20.
Is equivalent. ) Is equivalent to the contact member.

The front end face 3c of the core 3 is formed by a plane 3c (same reference numeral) perpendicular to the axis L. The rear end face 22b of the armature 22, the movable member 2 with respect to a plane 22b ₁ and the plane 22b ₁ perpendicular to the axis L ₁
A taper angle θ ₂ larger than a tilt angle θ _{1 of} 0 (see FIG. 11)
It is formed with a tapered surface 22b ₂ which is inclined with a. The flat surface 22b is provided on the rear end surface 22b of the armature 22.
₁ and the tapered surface 22b ₂ to form the core 3
Abutment 22b ₃ consisting ridge positioned on the circumference line of the smaller diameter D than the outer diameter of the counter range H of the front surface 3c opposite to the radial direction of the is provided. The rear end face 22b of the armature 22 is shown in FIG.

In FIG. 9, between the outer peripheral surface of the large-diameter cylindrical portion 22A of the armature 22 and the inner peripheral wall 2a of the concentric ring body 2 that guides the large-diameter cylindrical portion 22A, a movable body 20 is provided. A clearance C for enabling a smooth sliding operation is set. Due to the setting of the clearance C and the urging of the movable body 20 by the valve spring 16 (see FIG. 1), the armature 22 tilts with respect to the axis L of the core 3 as shown in a sectional view of a main part in FIG. with the angle θ ₁ to slide always inclined state.
For this reason, the armature 22 and the core 3 at the time of sliding by energization of the solenoid coil 6 are opposed to the opposing surfaces 3c, 22b.
Instead of making surface contact with each other, the contact portion 22b ₃ of the armature 22 and the front end surface (plane) 3c of the core 3 make point contact at point P.

According to the above fuel injection valve, the armature 22 and the core 3 of the movable body 20 at the time of sliding by energization of the solenoid coil 6 are connected to the rear end face 22 of the armature 22.
b, the abutment portion 22b ₃ is located between the front end face 3c of the core 3 and point P
Contact by point contact at. At this time,
The diameter D is smaller than the outer diameter of a radially opposed range H in which the contact portion 22b ₃ faces the front end face 3c of the core 3 (see FIG. 9).
, The point P at which the movable body 20 contacts the core 3 at the point P is a point P on the outer peripheral edge of the conventional movable body 20.
₁ (see FIG. 14), the position is closer to the axial center, and the moment is smaller. Therefore, the movable body 2
By reducing the stress locally applied at the time of contact between the core 0 and the core 3, the wear caused by the repeated contact between the movable body 20 and the core 3 can be prevented. Performance can be improved.

Further, the opposing surfaces of the movable body 20 and the core 3 are
Components to be Formed: Armature 22 and Core
Numerals 3 denote members forming magnetic paths, respectively.
22 has an axis L₁Plane 22b orthogonal to₁
And its plane 22b₁Of the movable body 20 with respect to₁Than
Large taper angle θ_TwoTapered surface 22b inclined with _Two
And the front end face 3c of the core 3 is orthogonal to the axis L.
It is formed in a plane. For this reason, armature 22
Plane 22b of rear end face 22b₁And tapered surface 22b _TwoAnd by
Abutting part 22b_ThreeCan be easily formed as
When the movable body 20 is tilted, the rear end face of the armature 22
The ridge line formed at 22b is always the front end face 3c of the core 3.
Can abut. In addition, the opposing surfaces (3c, 22
b) mutual planes (3c, 22b)₁) Confirm the opposing part of the comrades
This prevents the magnetic path area from decreasing.
Wear.

Embodiment 2 Embodiment 2 will be described with reference to a partial cross section of FIG. Embodiment 2
Since the first embodiment has been modified, the changed parts will be described in detail, and redundant description will be omitted. 12, in the present embodiment, the rear end face 22b of the armature 22
It is formed by a plane 22b perpendicular to the axis L ₁ (the same reference numerals.). Also, the front end face 3c of the core 3
Is formed with respect to a plane 3c ₁ and the plane 3c ₁ perpendicular to the axis L by the tapered surface 3c ₂ to inclined at an inclination angle theta ₁ (see FIG. 11) is greater than the taper angle theta ₂ of the movable member 20. By forming the planar 3c ₁ and the tapered surface 3c ₂ to the front end face 3c of the core 3 is positioned on the circumference line of the smaller diameter D than the outer diameter of the radial facing range H that faces the rear end surface 22b of the armature 22 abutment 3c ₃ is provided comprising a ridgeline. According to the present embodiment, substantially the same operation and effect as those of the first embodiment can be obtained.

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 member that regulates the sliding position of the movable body 20 is not limited to the core 3 and the armature 22 that form a magnetic path, and may be a member that does not form a magnetic path.
Further, instead of the tapered surfaces 22b ₂ and 3c ₂ , a convex curved surface or a concave curved surface may be formed. It is also conceivable that the rear end face 22b of the armature or the front end face 3c of the core 3 is formed as a convex curved surface, and one point on the convex curved surface is set as a contact portion.

[0032]

According to the fuel injection valve of the present invention, it is possible to prevent wear due to repeated contact between the movable body and the contact member, thereby improving durability and reliability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection valve according to a first 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 of an armature and a core.

FIG. 10 is an end view of the armature.

FIG. 11 is a cross-sectional view of a main part showing a contact state between an armature and a core.

FIG. 12 is a cross-sectional view of a main part of an armature and a core according to a second embodiment.

FIG. 13 is a sectional view of a main part of a conventional movable body and a contact member.

FIG. 14 is a cross-sectional view of a main part showing a contact state between a movable body and a contact member.

[Explanation of symbols]

Reference Signs List 3 core (contact member) 3c front end face 3c ₁ plane 3c ₂ tapered surface 3c ₃ contact part 6 solenoid coil 20 movable body 22 armature (a component forming a facing surface of movable body) 22b rear end face 22b ₁ plane 22b ₂ inclination angle theta ₂ taper angle of the tapered surface 22b ₃ abutting portion theta ₁ movable body

Claims (2)

[Claims] 1. A movable body that slides in an axial direction by being attracted by energization of a solenoid coil and a sliding position of the movable body that slides when energized by the solenoid coil when the opposing surfaces oppose each other on the same axis. A contact member that is regulated by contact with the movable member and the contact member, wherein one of the opposed surfaces of the movable member and the contact member has an outer diameter in a radially opposed range opposed to the other opposed surface. A fuel injection valve provided with a contact portion located on a circumferential line having a smaller diameter and making point contact with the other facing surface due to the inclination of the movable body. 2. The fuel injection valve according to claim 1, wherein constituent members forming the opposing surfaces of the movable body and the contact member are members forming magnetic paths, respectively, and one of the opposing surfaces is orthogonal to the axis. A fuel injection valve formed of a flat surface and a tapered surface inclined with a taper angle larger than the tilt angle of the movable body with respect to the flat surface, and the other opposing surface is formed of a plane orthogonal to the axis.