JP2002081356A - Electromagnetic fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily provide the coaxial arrangement of first and second guide parts for guiding the axial sliding of a movable core and a valve element with a high accuracy in an electromagnetic fuel injection valve. SOLUTION: First and second fitting tubular parts 3a and 2a fitted to each other are formed in a valve seat member 3 and a valve housing 2, and a first guide part 9 slidably supporting the valve element 16 in the axial direction is formed in the valve seat member 3a on the same axis with the first fitting tube part 3a. Also, a second guide part 13 for guiding the axial sliding of the movable core 12 is forded in the valve housing 2 on the same axis with the second fitting tubular part 2a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve mainly used for a fuel supply system of an internal combustion engine, and more particularly to a valve seat having a fuel outlet hole and a valve seat connected to the inner end of the fuel outlet hole. A member, an injector plate having a plurality of fuel injection holes communicating with an outer end of the fuel outlet hole and joined to one end surface of the valve seat member, and one end connected to the other end of the valve seat member A valve housing accommodated in the valve housing and cooperating with the valve seat; a fixed core coupled to the other end of the valve housing via a non-magnetic annular spacer; A movable core integrally connected to the valve body, and a coil wound around the outer periphery of the fixed core. When the coil is energized, the fixed core moves the movable core in the axial direction. To open the valve by suction The thing ゝ relates to an improvement.

[0002]

2. Description of the Related Art Conventionally, such an electromagnetic fuel injection valve is already known as disclosed in, for example, Japanese Patent Application Laid-Open No. H11-166461.

[0003]

SUMMARY OF THE INVENTION In the above conventional device,
In order to stabilize the opening / closing operation along the axial direction of the movable core and the valve element integrally connected, a first guide portion for guiding the movable core in the axial direction is formed on the non-magnetic annular spacer.
In addition, a second guide portion that guides the sliding of the valve body in the axial direction is formed on the valve seat member.

[0004] However, it is extremely difficult to arrange the first and second guide portions coaxially with high precision on the annular spacer and the valve seat member provided with the valve housing interposed therebetween.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and easily and accurately obtains a coaxial arrangement of first and second guides for guiding the movable core and the valve body in the axial direction. It is an object of the present invention to provide the above-mentioned electromagnetic fuel injection valve.

[0006]

To achieve the above object, the present invention provides a valve seat member having a fuel outlet hole and a valve seat connected to the inner end of the fuel outlet hole, and an outer end of the fuel outlet hole. An injector plate having a plurality of fuel injection holes communicating with the valve seat and joined to one end surface of the valve seat member; a valve housing having one end connected to the other end of the valve seat member; A valve body cooperating with the valve seat, a fixed core connected to the other end of the valve housing via a non-magnetic annular spacer, and integrated with the valve body so as to face the fixed core. A movable core and a coil wound around the outer periphery of the fixed core. When the coil is energized, the fixed core attracts the movable core in the axial direction to open the valve body. An electromagnetic fuel injection valve, First and second fitting cylinder portions are formed on the member and the valve housing, respectively, and a first guide portion for supporting the valve body slidably in the axial direction is formed on the valve seat member. A first guide portion is formed coaxially with the fitting tube portion, and a second guide portion for guiding the movable core in the axial direction is formed coaxially with the second fitting tube portion on the valve housing. Features.

The first and second guides correspond to a guide hole and an annular guide in an embodiment of the present invention, which will be described later.

According to the first feature, the valve seat member is subjected to the coaxial machining of the first fitting cylinder and the first guide so that the first fitting cylinder and the guide hole can be coaxially formed with high precision. And the valve housing is subjected to coaxial processing of the second fitting cylinder and the second guide, so that the second fitting cylinder and the second guide have high-precision coaxiality. Therefore, when the first and second fitting cylinder portions are fitted to each other, the coaxiality of the first guide portion and the second guide portion can also be improved. The opening and closing operations of the valve element and the movable core are properly regulated without tilting by the first and second guide portions, so that the valve opening gap of the valve element is stabilized, and furthermore, the fuel injection characteristics are stabilized. Can contribute.

In addition, the present invention is characterized in that, in addition to the first feature, a hardened layer is formed on at least one of the sliding surfaces of the first guide portion and the movable core facing each other.

According to the second feature, the abrasion resistance of the sliding surfaces of the first guide portion and the movable core can be improved.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on embodiments of the present invention shown in the accompanying drawings.

FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. FIG. 4 is a view 4-4 of FIG.
5 is a sectional view taken along line 5-5 of FIG. 2, FIG. 6 is a sectional view taken along line 6-6 of FIG. 2, and FIG. 7 is a sectional view corresponding to FIG. 2, showing a second embodiment of the present invention. It is.

First, a description will be given of a first embodiment of the present invention shown in FIGS.

1 and 2, a casing 1 of an electromagnetic fuel injection valve I for an internal combustion engine is fluid-tightly connected to a cylindrical valve housing 2 (magnetic material) and a front end of the valve housing 2. A cylindrical valve seat member 3 having a bottom and a valve housing 2
And a cylindrical fixed core 5 which is liquid-tightly connected to the rear end with an annular spacer 4 interposed therebetween.

The spacer 4 is made of a non-magnetic metal, for example, stainless steel. The valve housing 2 and the fixed core 5 are abutted against both end surfaces thereof and are welded all around in a liquid-tight manner.

A first fitting cylindrical portion 3a and a second fitting cylindrical portion 2a are formed at opposed ends of the valve seat member 3 and the valve housing 2, respectively. Then, the first fitting cylinder 3a is fitted into the second fitting cylinder 2a together with the stopper plate 6, and the stopper plate 6 is sandwiched between the valve housing 2 and the valve seat member 3. Thereafter, laser welding or beam welding is performed over the entire periphery of a corner portion sandwiched between the outer peripheral surface of the first fitting tubular portion 3a and the end face of the second fitting tubular portion 2a, so that the valve housing 2 and the valve seat member 3 are formed. Are connected to each other in a liquid-tight manner.

The valve seat member 3 has a fuel outlet hole 7 opened at the front end surface thereof, a conical valve seat 8 connected to the inner end of the fuel outlet hole 7, and a cylindrical member connected to a large diameter portion of the valve seat 8. And a guide hole 9 which is formed coaxially with the second fitting cylindrical portion 2a.

An injector plate 10 (see FIG. 3) made of a steel plate and having a plurality of fuel injection holes 11 communicating with the fuel outlet holes 7 is liquid-tightly welded to the front end surface of the valve seat member 3 over the entire circumference.

A movable core 12 facing the front end face of the fixed core 5 is accommodated in the valve housing 2 and the annular spacer 4, and an annular guide portion 13 for supporting the movable core 12 slidably in the axial direction is provided in the valve housing 2. 2 protrudes from the inner peripheral surface of the rear end. A plurality of axial grooves 14 (see FIG. 5) that allow fuel to flow are provided at equal intervals in the circumferential direction on the inner peripheral surface of the annular guide portion 13. A hardened layer 15 by shot peening or chrome plating is formed on at least one of the sliding surfaces of the annular guide portion 13 and the movable core 12 facing each other, in the illustrated example, the annular guide portion 13. The hardened layer 15 can improve the wear resistance of the sliding surface.

The movable core 12 is integrally provided with a small-diameter rod portion 12a extending from one end surface thereof to the valve seat 8 side, and a spherical valve which can be seated on the valve seat 8 at the tip of the rod portion 12a. The body 16 is fixed by welding. The valve body 16 is axially slidably supported in the guide hole 9 and has a plurality of chamfered portions 17 (FIG. 4) on its outer peripheral surface to allow fuel to flow through the guide hole 9. Are formed at regular intervals.

The stopper plate 6 has a rod 12a.
There is provided a U-shaped notch 18 (see FIG. 6) through which the stopper plate 6 faces the end surface of the stopper plate 6 on the valve seat 8 side. . When the valve body 16 is closed, that is, when the valve body 16 is seated on the valve seat 8, a gap g corresponding to the valve opening stroke of the valve body 16 is provided between the stopper plate 6 and the stopper flange 19.
Is provided. On the other hand, a gap is provided between the fixed core 5 and the movable core 12 so as to avoid contact between the cores 5 and 12 even when the valve body 16 is closed, that is, when the valve body 16 is seated on the valve seat 8. Can be

The fixed core 5 has a hollow portion 21 communicating with the inside of the valve housing 10 through the through hole 20 of the movable core 12, and the movable core 12 is inserted into the hollow portion 21 in the closing direction of the valve body 16. That is, a coil-shaped valve spring 22 that urges the valve seat 8 in the seating direction and a pipe-shaped retainer 23 that supports the rear end of the valve spring 22 are housed.

At this time, a positioning recess 24 for receiving the front end of the valve spring 22 is formed on the rear end surface of the movable core 12. The set load of the valve spring 22 is adjusted by the press-fit depth of the retainer 23 into the hollow portion 21.

At the rear end of the fixed core 5, an inlet tube 26 having a fuel inlet 25 communicating with the hollow portion 21 of the fixed core 5 via a pipe-shaped retainer 23 is integrally connected, and is connected to the fuel inlet 25. The fuel filter 35 is mounted.

A coil assembly 28 is fitted around the outer periphery of the annular spacer 4 and the fixed core 5. The coil assembly 28 includes a bobbin 29 fitted on the outer peripheral surface of the annular spacer 4 and the fixed core 5 and a coil 30 wound therearound. A coil housing 31 surrounding the coil assembly 28 Is welded to the outer peripheral surface of the valve housing 2 by welding.

Coil housing 31, coil assembly 28
The fixed core 5 is embedded in a cover 32 made of synthetic resin, and a coupler 34 for accommodating a connection terminal 33 connected to the coil 30 is integrally provided at an intermediate portion of the cover 32. .

An annular groove 36 is defined between the front end surface of the cover 32 and a synthetic resin cap 35 fitted to the front end of the valve seat member 3. An O-ring 37 closely attached to the outer peripheral surface of the fuel injection valve 2 is attached to an inner peripheral surface of the mounting hole when the electromagnetic fuel injection valve I is mounted in a fuel injection valve mounting hole of an intake manifold (not shown). It comes to be close to. Next, the operation of the first embodiment will be described.

As shown in FIG. 2, when the coil 30 is demagnetized, the movable core 12 and the valve element 18 are pressed forward by the urging force of the valve spring 22, and the valve element 18 is seated on the valve seat 8. . Therefore, the high-pressure fuel supplied into the valve housing 1 through the fuel filter 35 and the inlet tube 26 is retained in the valve housing 1.

When the coil 30 is excited by energization, the magnetic flux generated by the excitation is fixed core 5, coil housing 3
1, the valve housing 10 and the movable core 12 run sequentially, and the magnetic force attracts the movable core 12 with the valve element 18 to the fixed core 5 and opens the valve seat 8, so that the high-pressure fuel in the valve housing 10 is removed. After exiting the fuel outlet 13, the fuel injection hole 11
Is injected toward the intake valve of the engine.

At this time, the valve opening limit of the valve element 18 is defined by the stopper flange 19 connected to the movable core 12 abutting on the stopper plate 6, and there is a minute gap between the opposed surfaces of the fixed core 5 and the movable core 12. Gaps remain.

Therefore, when the coil 30 is degaussed again, the residual magnetism between the fixed and movable cores 5 and 12 becomes extremely small, and the movable core 12 is immediately advanced by the urging force of the valve spring 22 and the valve body is moved. 18 can be returned to the initial valve closing state, which can contribute to an improvement in valve closing response.

Incidentally, the movable core 12 connected integrally
The valve body 16 is slidably supported at both ends thereof by an annular guide portion 13 protruding from the inner peripheral surface of the valve housing 2 and a guide hole 9 of the valve seat member 3. The body 16 can be accurately opened and closed in the axial direction without tilting. As a result, when the valve is opened, the stopper flange 1 is opened.
9 accurately contacts the stopper plate 6, so that the valve opening gap of the valve body 16 with respect to the valve seat 8 can be always kept constant.

In particular, the valve seat member 3 and the valve housing 2
A first fitting cylinder portion 3a and a second fitting cylinder portion 2a fitted to each other;
Respectively, so that the first fitting cylindrical portion 3
a and the guide hole 9 can be coaxially processed to easily obtain high-precision coaxiality between the first fitting cylindrical portion 3a and the guide hole 9; 2a
The coaxial processing of the annular guide portion 13 and
High-precision coaxiality of the fitting tube portion 2a and the annular guide portion 13 can be easily obtained. Therefore, when the first and second fitting tube portions 3a, 2a are fitted to each other, the guide holes 9 and The coaxiality of the annular guide portion 13 also becomes highly accurate, which can stabilize the valve opening gap of the valve body 16, that is, stabilize the fuel injection characteristics.

Next, a second embodiment of the present invention shown in FIG. 7 will be described.

In the second embodiment, instead of the stopper plate 6 and the stopper flange 19 in the previous embodiment, a stopper surface 38 projecting radially inward from the inner peripheral surface of the annular guide portion 13 is provided on the annular spacer 4. An annular shoulder 39 is formed on the outer periphery of the movable core 12 and formed on the outer surface of the movable core 12 so as to abut on the stopper surface 38 and define the valve opening limit of the valve body 16. The other structure is the same as that of the previous embodiment. So
7, parts corresponding to those of the previous embodiment are denoted by the same reference numerals, and description thereof is omitted.

The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention.

[0037]

As described above, according to the first aspect of the present invention, there is provided a valve seat member having a fuel outlet hole and a valve seat connected to an inner end of the fuel outlet hole, and a valve seat member having an outer end of the fuel outlet hole. An injector plate having a plurality of communicating fuel injection holes and joined to one end surface of the valve seat member; a valve housing having one end connected to the other end of the valve seat member; and a valve housing accommodated in the valve housing. A valve body cooperating with the valve seat, a fixed core coupled to the other end of the valve housing via a non-magnetic annular spacer, and opposed to the fixed core to be integral with the valve body. And a coil wound around the outer periphery of the fixed core. When the coil is energized, the fixed core attracts the movable core in the axial direction to open the valve body. In the electromagnetic fuel injection valve,
A first fitting which is fitted to the valve seat member and the valve housing.
And a second fitting cylinder portion, and a first guide portion for supporting the valve body slidably in the axial direction is formed on the valve seat member coaxially with the first fitting cylinder portion. In the valve housing, the second guide portion for guiding the sliding of the movable core in the axial direction is formed coaxially with the second fitting tube portion, so that the first and second fitting tube portions are fitted to each other. Inevitably, the coaxiality of the first guide portion and the second guide portion can be inevitably high, and therefore, the opening and closing operations of the valve element and the movable core are properly regulated by these, and the opening of the valve element is performed. Stabilization of valve gap,
As a result, the fuel injection characteristics can be stabilized.

According to the second feature of the present invention, a hardened layer is formed on at least one of the sliding surfaces of the first guide portion and the movable core facing each other. The wear resistance of the sliding surface can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electromagnetic fuel injection valve for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 2;

FIG. 6 is a sectional view taken along line 6-6 of FIG. 2;

FIG. 7 is a sectional view corresponding to FIG. 2, showing a second embodiment of the present invention.

[Explanation of symbols]

 ... Electromagnetic fuel injection valve 2... Valve housing 2a... Second fitting cylinder 3... Valve seat member 3a. 4 ... spacer 5 ... fixed core 7 ... fuel outlet hole 8 ... valve seat 6 ... 1st guide part (guide hole) 10 ... · Injector plate 11 ··· Fuel injection hole 12 ··· Movable core 13 ··· Second guide portion (annular guide portion) 15 ··· Hardened layer 16 ··· Valve element 30 ··· ·coil

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02M 61/12 F02M 61/12 61/16 61/16 M 61/18 360 61/18 360A

Claims (2)

[Claims] 1. A valve seat member (3) having a fuel outlet hole (7) and a valve seat (8) connected to an inner end of the fuel outlet hole (7), and a valve seat member (3) at an outer end of the fuel outlet hole (7). An injector plate (10) having a plurality of communicating fuel injection holes (11) and joined to one end surface of the valve seat member (3); and one end portion at the other end of the valve seat member (3). A valve housing (2) to be connected, a valve body (16) housed in the valve housing (2) and cooperating with the valve seat (8), and a nonmagnetic annular member at the other end of the valve housing (2). A fixed core (5) connected via a spacer (4) and a movable core (12) integrally connected to the valve body (16) so as to face the fixed core (5); , A coil (30) wound around the outer periphery of the fixed core (5).
0), the fixed core (5) is moved to the movable core (12).
The valve body (16) is opened by sucking the oil in the axial direction. In the electromagnetic fuel injection valve, the first valve fitting member (3) and the valve housing (2) are fitted to each other.
And a second fitting cylinder portion (3a, 2a), and a first guide portion (9) for supporting the valve body (16) slidably in the axial direction is provided on the valve seat member (3). A second coaxial member is formed coaxially with the first fitting cylindrical portion (3a) and guides the movable core (12) in the axial direction to the valve housing (2).
An electromagnetic fuel injection valve, wherein the guide portion (13) is formed coaxially with the second fitting cylinder portion (2a). 2. The electromagnetic fuel injection valve according to claim 1, wherein a hardened layer (15) is formed on at least one of the sliding surfaces of said first guide portion (9) and said movable core (12) facing each other. An electromagnetic fuel injection valve, characterized in that: