JPH11280592A - Fuel injector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately fix an injection nozzle to an injector main body, suppress fluctuation of lift amount of a valve element and stabilize fuel injection amount. SOLUTION: In a state that a valve element 3 and a stopper plate 6 are incorporated, an injection nozzle 22 is fitted into a nozzle fitting part 21B of an injector main body 21, a locking step part 23B of a cap 23 is locked on an annular step part 22E of the injection nozzle 22 and a welding part 23C of the cap 23 is welded on the injector main body 21. By this cap 23, the injection nozzle 22 is indirectly fixed to the injector main body 21. As a result, gaps between the annular step part 22E and the stopper plate 6 and between an abutting step part 21D and the stopper plate 6 are eliminated, fluctuation of lift amount ΔL of the valve element 3 is suppressed and fuel injection amount can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injector suitable for use in a fuel injection device of, for example, an automobile engine.

[0002]

2. Description of the Related Art Generally, a fuel injection device for an automobile engine or the like is configured to inject fuel in a fuel tank from a plurality of fuel injectors to each cylinder of the engine. As a conventional fuel injector of this type, a top-feed type fuel injector that supplies fuel into the injector body from the longitudinal end side of the fuel injector and a radially intermediate portion of the injector body in the longitudinal direction are provided. 2. Description of the Related Art A side-feed type fuel injector that supplies fuel from the outside in a direction is known.

Therefore, a fuel injector of the prior art will be described with reference to FIGS. 3 and 4, taking a top feed type fuel injector as an example.

[0004] Reference numeral 1 denotes an injector main body formed in a stepped cylindrical shape from a magnetic material such as electromagnetic stainless steel. The injector main body 1 is integrally formed with a large-diameter cylindrical portion 1A and a distal end of the large-diameter cylindrical portion 1A. Nozzle fitting portion 1B of small diameter formed in
And a contact step 1C formed on the bottom side of the nozzle fitting portion 1B and contacted by a stopper plate 6 described later, and the tip end of the nozzle fitting portion 1B has an annular shape of an injection nozzle 2 described later. A caulked portion 1D that engages with the step portion 2E is formed.

A stepped cylindrical injection nozzle 2 is caulked and fixed to the inner peripheral side of the nozzle fitting portion 1B by a caulking portion 1D of the injector body 1. The injection nozzle 2 is made of a hard metal material such as stainless steel. Is formed. Also,
The injection nozzle 2 has an insertion hole 2A for the valve body 3 described later,
A substantially conical valve seat 2B on which the valve portion 3B of the valve body 3 is detached and seated;
An injection nozzle 2 </ b> C opened at the tip end surface of the injection nozzle 2. In addition, the base end surface of the injection nozzle 2 becomes an annular convex portion 2D with which the stopper plate 6 abuts, and a caulked portion 1D of the injector body 1 is provided on the outer periphery of the axially intermediate portion.
Is formed to form an annular stepped portion 2E.

Reference numeral 3 denotes a valve element for opening and closing the injection port 2C of the injection nozzle 2. The valve element 3 includes a valve shaft 3A slidably inserted into an insertion hole 2A of the injection nozzle 2. The valve shaft 3A includes a substantially conical valve portion 3B formed on the distal end side of the valve shaft 3A, and a flange-shaped stopper portion 3C provided at an axially intermediate portion of the valve shaft 3A. Further, a fuel passage 4 extending in the axial direction is formed in the insertion hole 2A on the outer peripheral side of the valve shaft 3A.

The valve body 3 is opened by supplying power to an electromagnetic actuator 7, which will be described later.
As shown in the figure, a predetermined lift amount ΔL from the valve closing position to the valve opening position where the stopper portion 3 </ b> C contacts the stopper plate 6.
It is slid and displaced by the minute.

[0008] Reference numeral 5 denotes an anchor formed of a magnetic material such as electromagnetic stainless steel into a closed cylindrical shape. The anchor 5 is fitted to the base end side of the valve body 3 and a core member 8 of the electromagnetic actuator 7.
And a predetermined size gap therebetween. A fuel passage (not shown) is provided on the outer peripheral side of the anchor 5 in the axial direction.

Reference numeral 6 denotes a stopper plate formed, for example, in a substantially C shape. The stopper plate 6 is located in the nozzle fitting portion 1B of the injector body 1 and is in contact with the contact step 1C of the injector body 1 and the injection nozzle. 2 between the annular protrusion 2D and regulates the lift amount ΔL of the valve body 3.

Reference numeral 7 denotes an electromagnetic actuator provided in the injector body 1. The electromagnetic actuator 7 includes a core member 8 formed of a magnetic material such as electromagnetic stainless steel in a stepped cylindrical shape, and an injector together with the core member 8. An annular electromagnetic coil 9 is fixed by caulking to the large-diameter cylindrical portion 1A of the main body 1. The electromagnetic actuator 7 magnetically attracts the anchor 5 using the core member 8 when the electromagnetic coil 9 is externally supplied with power using the connector 10, thereby opening the valve body 3. is there.

Reference numeral 11 denotes a valve spring which constantly urges the valve body 3 in the valve closing direction. The valve spring 11 is disposed between the tubular body 12 fitted in the core member 8 and the anchor 5, When the valve body 3 is closed, the valve portion 3B is held in a state of being seated on the valve seat 2B of the injection nozzle 2.

Reference numeral 13 denotes a fuel hose connected to the base end of the core member 8. The fuel hose 13 supplies fuel discharged from a fuel pump (not shown) provided in a vehicle such as an automobile to the injector body 1. It is supplied inside.

The fuel injector according to the prior art has the above-described configuration, and the fuel discharged from the fuel pump is supplied to the fuel passage 4 in the injection nozzle 2 through the fuel hose 13, the cylinder 12, and the like.

When the power supply to the electromagnetic actuator 7 is stopped, the valve portion 3B of the valve body 3
Is seated on the valve seat 2B of the injection nozzle 2 by the urging force, and the valve body 3 holds the valve closed state.

The electromagnetic actuator 7 has a connector 1
When power is supplied from zero, the electromagnetic coil 9 magnetically attracts the anchor 5 using the core member 8, and the valve body 3 opens together with the anchor 5 against the valve spring 11. Thereby, the valve element 3
3B is lifted from the valve seat 2B of the injection nozzle 2 by a lift amount ΔL.
The fuel in the fuel passage 4 is injected to the outside from the injection port 2C of the injection nozzle 2 by a distance.

[0016]

In the prior art described above, the injection nozzle 2 and the stopper plate 6 are caulked and fixed to the inner peripheral side of the nozzle fitting portion 1B of the injector body 1, so that the injector body 1 is fixed. In the injection nozzle 2 and the like, distortion, deformation, and the like due to the pressing force when forming the caulked portion 1D are likely to occur. In addition, caulking part 1
D may also be deformed by springback of the metal after caulking.

Therefore, between the annular convex portion 2D of the injection nozzle 2 and the stopper plate 6, or between the injector main body 1
A slight gap may be formed between the contact step portion 1C and the stopper plate 6, and the actual lift amount ΔL regulated by the stopper plate 6 is likely to fluctuate.
There is a problem that the fuel injection amount becomes unstable.

On the other hand, a welding portion is formed between the nozzle fitting portion 1B of the injector body 1 and the injection nozzle 2 by using welding means such as laser welding, electron beam welding, or the like.
A method of directly fixing the injection nozzle 2 to the injector body 1 is also conceivable.

However, in this case, the injector body 1 and the injection nozzle 2 are likely to be thermally deformed or distorted due to heat at the time of welding. Therefore, the nozzle fitting portion 1B is formed to be thin and the heating time during welding is increased. It is difficult to accurately fix the injection nozzle 2 to the injector body 1 unless the strength and reliability of the nozzle fitting portion 1B are reduced.

The present invention has been made in view of the above-described problems of the prior art. The present invention provides a fuel injector in which an injection nozzle can be accurately fixed to an injector body and a lift amount of a valve body can be stabilized. It is intended to provide.

[0021]

Means for Solving the Problems To solve the above-mentioned problems, a fuel injector according to the present invention has an electromagnetic actuator provided therein, and a cylindrical nozzle fitting portion formed at an axially distal end side. An injector body, an injection nozzle having a base end side fitted to an inner peripheral side of a nozzle fitting portion of the injector body, and an injection port formed at a distal end side; and the electromagnetic actuator provided slidably in the injection nozzle. Is provided between the valve body that opens and closes the injection port of the injection nozzle by being driven by the nozzle, and the nozzle fitting portion of the injector body and the base end side of the injection nozzle, and when the valve element opens. And a stopper plate for determining the lift amount of the motor.

The feature of the means adopted in the first aspect of the invention is that the injection nozzle is fixed to the nozzle fitting portion of the injector body in a state where the valve body and the stopper plate are assembled. And a cylindrical cap whose base end is welded to the injector body by welding means.

With this configuration, the injection nozzle can be indirectly fixed to the injector main body by the cap welded to the injector main body. This eliminates caulking of the tip of the nozzle fitting portion, which has conventionally been performed to fix the injection nozzle to the injector body, and can maintain a constant lift amount when the valve body is opened by the electromagnetic actuator.

Further, since the injection nozzle is not directly welded to the injector body but is indirectly fixed to the injector body using a cap, the injection nozzle is prevented from being thermally deformed or distorted due to heat during welding. can do.

According to the second aspect of the present invention, an annular step is formed on the outer periphery of the injection nozzle, and the cap is provided on the cylindrical portion fitted on the outer periphery of the injection nozzle and on the inner circumference on the tip end side of the cylindrical portion. A locking step locked to the annular step of the injection nozzle; and a welding means for welding to the outer periphery of the injector body by being fitted to the outer periphery of the injector body provided on the base end side of the cylindrical portion. And a welded part.

With this configuration, the annular step portion of the injection nozzle is locked to the locking step formed at the distal end side of the cylindrical portion of the cap, and the welded portion formed at the base end side of the cylindrical portion is formed. The outer periphery of the injector body and the welded portion are welded in a state of being fitted to the outer periphery of the injector body. Then, the cap fixes the injection nozzle to the injector body, and can accurately position the injection nozzle in the axial direction.

According to a third aspect of the present invention, the injector body and the base end side of the cap are welded by welding means while the cap is pressed against the injector body side.

With this configuration, the gap between the injection nozzle and the stopper plate can be eliminated by welding the cap to the injector body while the cap is pressed against the injector body, and the valve lift can be reduced. Can always be set constant.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a fuel injector according to the present invention will be described in detail with reference to FIGS. In the present embodiment, the same components as those of the above-described related art are denoted by the same reference numerals, and description thereof will be omitted.

Reference numeral 21 denotes a conventional injector body 1.
Instead of the injector body 21 used in the present embodiment, the injector body 21 differs from the injector body 1 according to the prior art in that the large-diameter cylindrical portion 21A and the large-diameter cylindrical portion 21A
A small-diameter cylindrical nozzle fitting portion 21B integrally formed on the tip side of the nozzle, an outer step portion 21C formed on an outer peripheral surface between the nozzle fitting portion 21B and the large-diameter cylindrical portion 21A, It is constituted by a contact step portion 21D formed on the bottom side of the nozzle fitting portion 21B and in contact with the stopper plate 6. The core member 8 and the electromagnetic coil 9 are provided in the large-diameter cylindrical portion 21A.
Are accommodated.

Reference numeral 22 denotes a stepped cylindrical injection nozzle housed in a nozzle fitting portion 21B of the injector body 21. The injection nozzle 22 is formed of a hard metal material such as stainless steel and extends in the axial direction. Insertion hole 22A for valve body 3
And a substantially conical valve seat 22B on which the valve portion 3B of the valve shaft is seated
And an injection port 22 </ b> C opened at the tip end surface of the injection nozzle 22. The base end surface of the injection nozzle 22 is an annular convex portion 22D with which the stopper plate 6 contacts, and an annular step portion 22E is formed on the outer periphery of the axially intermediate portion to which the locking step portion 23A of the cap 23 is locked. Have been. Further, a fuel passage 4 extending in the axial direction is formed between the insertion hole 22A and the valve shaft 3A of the valve body 3.

Reference numeral 23 denotes a cylindrical cap.
Is a cylindrical portion 23A fitted to the outer periphery of the injection nozzle 22,
A locking step 23B provided on the inner circumference of the distal end side of the cylindrical section 23A and locked to the annular step 22E of the injection nozzle 22 is fitted to the outer circumference of the injector body 21 provided on the base end side of the cylindrical section 22A. In this state, the outer peripheral portion of the injector body 21 is welded to the welded portion 23C by welding means. The cap 23 has the valve body 3 inserted into the insertion hole 22A of the injection nozzle 22, and the injection nozzle 22 and the stopper plate 6 are fitted on the inner peripheral side of the nozzle fitting portion 21B of the injector body 21. And is welded to the injector body 21.

Here, when manufacturing the fuel injector, the electromagnetic actuator 7, the cylindrical body 12 and the like are mounted in the large-diameter cylindrical portion 21A of the injector body 21, and the valve body 3 is inserted into the insertion hole 22A of the injection nozzle 22. After the fitting, the injection nozzle 22 and the stopper plate 6 are fitted on the inner peripheral side of the nozzle fitting portion 21B of the injector body 21.

Then, the cylindrical portion 23A of the cap 23 is inserted from the distal end side of the injection nozzle 22, and the proximal end side of the cap 23 is brought closer to the outer step portion 21C of the injector body 21,
The welded portion 23C is connected to the large-diameter cylindrical portion 21A of the injector body 21.
To the outer periphery of the end. At this time, the locking step 23B of the cap 23 is locked to the annular step 22E of the injection nozzle 22, and the injection nozzle 22 is pressed against the injector body 21 as the cap 23 moves.

Further, with the cap 23 pressed against the injector body 21 from below with a predetermined load P, the welded portion 23C of the cap 23 and the end of the large-diameter cylindrical portion 21A of the injector body 21 are connected. , Welding by full circumference welding such as laser welding and electron beam welding.

Thus, the injection nozzle 22 is fixed with the cap 23 positioned in the axial direction with respect to the injector main body 21, between the annular convex portion 22 D and the stopper plate 6, or the contact step portion. The gap between 21D and the stopper plate 6 can be eliminated. Then, the lift amount from the valve closing position to the valve opening position where the stopper portion 3C of the valve body 3 abuts against the stopper plate 6 can be set to a predetermined lift amount ΔL.

The cap 23 is connected to the injector body 2
When the stopper plate 6 is pressed by the contact step 21D of the injector body 21 when the stopper plate 6 is pressed by the contact step 21D, the contact step 21D is deformed. The value is set to a value close to the limit value, which is set according to the material of the injector body 21.

For example, when electromagnetic stainless steel (KM35FL or the like) is used for the material of the injector body 21, this magnetic material is 60 kgf / 0.35 cm ² (that is, 171%).
The deformation of the contact step 21D starts from about kgf / m ² ). Therefore, the load P for pressing the cap 23 against the injector body 21 is specifically set to 150 kgf / m ² or less.

The fuel injector according to the present embodiment has the above-described configuration. Like the conventional fuel injector, when power is supplied to the electromagnetic actuator 7, the valve portion 3B of the valve body 3
From the valve seat 22B by the lift amount ΔL, and the fuel in the fuel passage 4 can be injected from the injection port 2C to the outside.

As described above, in the fuel injector according to the present embodiment, the injection nozzle 22 is indirectly fixed to the injector body 21 by the cap 23, so that the injection nozzle 22 is conventionally fixed to the injector body 21. The caulking part used in technology can be eliminated. Thereby, distortion, deformation, and the like of the injector body 21, the injection nozzle 22, and the like due to the pressure applied when forming the caulked portion can be eliminated.

The annular projection 22D of the injection nozzle 22
The gap between the stopper plate 6 and the contact step 21D of the injector body 21 and the stopper plate 6 can be eliminated, the fluctuation of the lift amount ΔL can be suppressed, and the fuel injection amount can be stabilized. it can.

Further, to fix the cap 23, the welded portion 23C is welded to the outer periphery of the large-diameter cylindrical portion 21A of the injector main body 21 in a state where the cap 23 is pressed against the injector main body 21 with a predetermined load P. From the injection nozzle 2
2 can be prevented from being thermally deformed or distorted due to heat at the time of welding in the injection nozzle 22 without directly welding the injector 2 to the injector body 21.

As a result, the injector body 21 and the injection nozzle 22 are securely welded by the cap 23, the lift amount ΔL of the valve body 3 can be further stabilized, and the yield at the time of manufacturing the fuel injector can be increased. Quality can be improved.

In the embodiment, the welded portion 23C of the cap 23 and the end of the large-diameter cylindrical portion 21A of the injector body 21 are welded by full circumference welding. However, the present invention is not limited to this. The cap 23 may be welded to the injector body 21.

In the embodiment, the injector main body 21 is formed by using welding means such as laser welding, electron beam welding or the like.
Although the case where the cap 23 is welded is described as an example,
The present invention is not limited to this, and other welding means such as arc welding may be used.

Further, in the embodiment, a top feed type fuel injector for supplying fuel into the injector body 1 through the fuel hose 13 or the like from the end side of the fuel injector has been described as an example of the prior art. The present invention is not limited to this, and may be applied to, for example, a side-feed type fuel injector that supplies fuel directly to the inside thereof through a fuel port or the like provided at an intermediate portion in the length direction of the injector body.

[0047]

As described above in detail, according to the first aspect of the present invention, the injection nozzle is fitted to the nozzle fitting portion of the injector body in a state where the valve body and the stopper plate are assembled, and the tip side is injected. Since the injection nozzle is indirectly fixed to the injector body using a cap that is locked to the outer peripheral side of the nozzle and the base end side is welded to the injector body by welding means, the conventional injection nozzle is fixed to the injector body. It eliminates caulking at the tip of the nozzle fitting part, which has been performed to fix the valve, suppresses fluctuations in the lift amount when the valve element is opened by the electromagnetic actuator, and keeps the fuel injected at the time of valve opening constant. it can.

Further, since the injection nozzle is indirectly fixed to the injector body by using a cap, it is possible to prevent the injection nozzle from being thermally deformed or distorted due to heat at the time of welding. Can be more stable,
The yield at the time of manufacturing the fuel injector can be increased and the quality can be improved.

According to the second aspect of the present invention, the annular step of the injection nozzle is locked to the locking step formed on the distal end side of the cylindrical portion of the cap, and the welded portion formed on the base end side of the cylindrical portion is connected to the injector. Since the welding portion is welded by welding means in a state of being fitted to the outer periphery of the main body, the injection nozzle is securely fixed to the injector main body by the cap, and the fluctuation of the lift amount of the valve body is suppressed. It is possible to stabilize the fuel injection amount during valve operation.

According to the third aspect of the present invention, the injector body and the base end side of the cap are welded by welding means in a state where the cap is pressed against the injector body side. By eliminating the gap with the plate, the lift amount of the valve body can be kept constant, and the fuel injection amount can be stabilized.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a fuel injector according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing an injection nozzle and the like in FIG. 1;

FIG. 3 is a longitudinal sectional view showing a conventional fuel injector.

FIG. 4 is an enlarged longitudinal sectional view showing an injection nozzle and the like in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Valve body 6 Stopper plate 7 Electromagnetic actuator 21 Injector main body 21B Nozzle fitting part 22 Injection nozzle 22C Injection port 22E Annular step part 23 Cap 23A Tube part 23B Locking step part 23C Welding part

Claims (3)

[Claims] 1. An electromagnetic actuator is provided inside,
An injector body having a cylindrical nozzle fitting portion formed on the distal end side in the axial direction, and an injection nozzle having a base end fitted on the inner peripheral side of the nozzle fitting portion of the injector body and having an injection port formed on the distal end side And slidably provided in the injection nozzle,
A valve body, which is driven by the electromagnetic actuator to open and close the injection port of the injection nozzle, is provided between a nozzle fitting portion of the injector body and a base end side of the injection nozzle. In a fuel injector including a stopper plate that determines a lift amount when valved, in order to fix an injection nozzle to a nozzle fitting portion of an injector body with the valve body and the stopper plate incorporated,
A fuel injector characterized in that a distal end side is locked to an outer peripheral side of the injection nozzle, and a base end side is provided with a cylindrical cap welded to an injector body by welding means. 2. An annular step portion is formed on the outer periphery of the injection nozzle, and the cap is provided on a cylindrical portion fitted on the outer periphery of the injection nozzle, and provided on an inner periphery on a distal end side of the cylindrical portion. A locking step locked to the annular step of the nozzle, and welding welded to the outer periphery of the injector body by welding means provided on the base end side of the cylinder and fitted to the outer circumference of the injector body. 2. The fuel injector according to claim 1, wherein the fuel injector comprises: 3. The fuel injector according to claim 1, wherein the cap is configured to weld the injector body and a base end side of the cap by welding means in a state where the cap is pressed against the injector body side.