JPH11303711A - Fuel injection nozzle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nozzle of an arbitrary nozzle shape having good measuring accuracy in a short time, suited for improving performance of an internal combustion engine. SOLUTION: This fuel injection nozzle is provided with a valve seat 1 having a valve hole 10 slidably provided with a valve 3 and a seat part 11 seated with the valve 3 and a nozzle tip 2 connected to the valve seat 1 and having a nozzle 20 jetting fuel flowing in the valve hole 10. Here, the nozzle 20 of the nozzle tip 2 is formed by laser work directly while properly feeding assist gas from the upstream of a hole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection nozzle in a fuel injection valve used for supplying fuel for an internal combustion engine.

[0002]

2. Description of the Related Art As shown in a partial sectional view of FIG. A fuel injection nozzle (reference numeral,
100 is attached. (See, for example, JP-A-9-6638)
No. 1). The injection hole 120 is formed by laser processing from the downstream side of the hole or the upstream side of the hole. In FIG. 20, the upper half of the fuel injection nozzle 100 is omitted. The fuel injection nozzle 100 is attached to a body of a fuel injection valve (not shown).

[0003]

In the conventional fuel injection nozzle 100, when the injection hole 120 is formed by laser processing from the downstream side of the hole, dross (dross means molten metal melts) inside the nozzle during laser processing. This may accumulate in the form of burrs.), Which may lead to a decrease in the accuracy of measuring the injected fuel. Further, since it is difficult to remove dross accumulated inside the nozzle, it is desirable to form the injection hole 120 by laser processing from the upstream side of the hole.

However, when laser processing the injection hole 120 from the upstream side of the hole, it is conventionally difficult to directly perform the laser processing on the injection hole 120 because it must be performed through the valve hole 110. For this reason, an optical fiber must be connected to the end of the laser light emitting means, and the optical fiber must be inserted into the valve hole 110 to perform indirect laser processing. By the way, since the emitted laser beam diverges in the optical fiber, it must be focused by a special focusing optical device. In addition, the valve hole 110 generally has a small inner diameter of about 6 mm, and there is a limit to a hole shape that can be formed due to space restrictions, and it is difficult to form a hole with good measurement accuracy. Further, since the optical fiber and the condensing optical device are in the way and the assist gas cannot be supplied to a desired portion, there remains a problem that it is difficult to form a hole with high measurement accuracy.

[0005] In order to form the injection hole with high accuracy in the measurement, electric discharge machining is sometimes used. However, electric discharge machining is not preferable because it requires much longer machining time than laser machining.

An object of the present invention is to provide a fuel injection nozzle capable of obtaining an injection hole having an arbitrary injection hole shape suitable for improving the performance of an internal combustion engine with good measurement accuracy in a short time. .

[0007]

According to a first aspect of the present invention, there is provided a valve seat having a valve hole in which a valve is slidably provided and a seat portion in which the valve is seated, and the valve seat is joined to the valve seat. And a nozzle tip having an injection hole for ejecting fuel flowing through the valve hole, wherein the injection hole of the nozzle tip is formed by laser processing from an upstream side of the hole. With this configuration, the injection hole of the nozzle tip can be formed by laser processing directly from the upstream side of the hole and while accurately supplying the assist gas. An injection hole having an arbitrary injection hole shape suitable for improving the performance of the engine can be obtained.

According to a second aspect of the present invention, there is provided the fuel injection nozzle according to the first aspect, wherein the injection hole of the nozzle tip is laser-processed from the downstream side of the hole. With this configuration, the dimensional accuracy on the downstream side of the injection hole can be improved.

According to a third aspect of the present invention, there is provided the fuel injection nozzle according to the first or second aspect, wherein an engaging means comprising a mutually engageable convex portion and a concave portion is provided between the joining surfaces of the valve seat and the nozzle tip. It is. With this configuration, the coaxiality at the time of joining the valve seat and the nozzle tip can be easily ensured by the engagement between the projection and the recess of the engagement means.

A fourth aspect of the present invention is the fuel injection nozzle according to any one of the first to third aspects, wherein both the valve seat and the nozzle tip are made of metal. With this configuration, the valve seat and the nozzle tip can be easily joined by welding, as compared with the case where the valve seat and the nozzle tip are made of different materials, so that the cost for the joining can be reduced.

[0011]

Embodiment 1 Embodiment 1 will be described with reference to the drawings. FIG. 1 shows a partial front sectional view of the fuel injection nozzle. In FIG. 1, the fuel injection nozzle comprises a substantially cylindrical valve seat 1 and a substantially flat nozzle tip 2 joined to the lower end surface thereof.

The valve seat 1 has a valve hole 10 in which a substantially needle-shaped valve 3 is slidable in the axial direction (vertical direction in the figure) and a seat portion 11 in which the valve 3 is seated. . The valve seat 1 is
It is made of metal formed by forging (for example, cold forging) or cutting. As a metal material of the valve seat 1, for example, a rod material of SUS440C is used.
Further, the valve seat 1 is quenched to improve the wear resistance of the seat portion 11. FIG. 2 is a partial sectional front view of the valve seat 1.

In FIG. 1, the nozzle tip 2 has an injection hole 20 for jetting fuel flowing through the valve hole 10. The injection hole 20 is opened like a slit in the wall of the sack 21 having a substantially hemispherical concave surface 21a. The nozzle tip 2 is formed of a metal plate. FIG. 3 is a front sectional view of the nozzle tip 2 and FIG.
FIG. 5 is a sectional view taken along line VV of FIG.

The manufacturing process of the nozzle tip 2 will be described. 6 shows a plan view of the material W of the nozzle tip 2, and FIG. 7 shows a sectional view taken along line VII-VII of FIG. As shown in FIGS. 6 and 7, the material W of the nozzle tip 2 is a metal plate-like material formed in a substantially rectangular shape by forging (for example, cold forging). As the metal material W of the nozzle tip 2, for example, SUS316 is used. The left and right ends of the material W are provided with positioning holes W1.
Are formed.

Next, FIG. 8 is a plan view, and FIG.
As shown in the cross-sectional view taken along the line IX, a sack 21 having a substantially hemispherical concave surface 21a at the center of the material W is formed by forging (for example, cold forging).

Next, as shown in a plan view of FIG. 10 and a sectional view taken along the line XI-XI of FIG. 10, an injection hole 20 is formed in the sac portion 21 of the material W by laser processing.

Next, a circular portion (two-dot chain line 200 in FIG. 10) including the sack portion 21 is punched out from the material W shown in FIGS. The nozzle tip 2 shown is completed.

By the way, the laser processing of the nozzle hole 20 is as follows.
It is not limited to the above-described process performed before the punching process, but may be performed after the punching process. Further, as shown in a sectional view of FIG. 12 and a sectional view taken along line XIII-XIII of FIG. 12, the nozzle chip 2 (or the material W) is fixed by a jig (not shown) or the like from the laser light source. The optical axis B1 of the emitted laser beam is shifted from
The light is emitted toward a, and is rotated about the vicinity of the radial center C of the concave surface 21a (see the arrow A1 in FIG. 13), thereby forming a slit-shaped injection hole 20 having a substantially fan-shaped cross section.

Nozzle tip 2 formed as described above
As shown in FIG. 1, the valve seat 1 is butted against the front end face (lower end face in the figure) of the valve seat 1 in a surface contact manner, and the peripheral portion of the butted face is welded (reference numeral 4 is attached to the drawing), for example, a laser. It is joined to the valve seat 1 by welding. After joining the valve seat 1 and the nozzle tip 2, the seat portion 11 is polished to complete the fuel injection nozzle. In FIG. 1, the upper half of the valve seat 1 is omitted. The fuel injection nozzle is mounted on the body of the fuel injection valve, as is well known.

According to the fuel injection nozzle configured as described above, the injection hole 20 is provided in the nozzle tip 2 unlike the conventional one.
Since the laser beam can be formed directly from the upstream side of the hole without passing through the valve hole 10 and while accurately supplying the assist gas, it can be formed by laser processing. Therefore, it is not necessary to use a special condensing optical device. It is possible to obtain an injection hole having an arbitrary injection hole shape (for example, a cylindrical shape, a fan-shaped slit, or the like) suitable for improving the performance of an internal combustion engine in a short time with good measurement accuracy.

Further, since both the valve seat 1 and the nozzle tip 2 are made of metal, the valve seat 1 and the nozzle tip 2 can be compared with the case where the valve seat 1 and the nozzle tip 2 are made of different materials. Can be easily joined by welding 4, so that the cost for the joining can be reduced.

In the laser processing of the injection hole 20, as shown in a sectional view of FIG. 14 and a sectional view taken along the line XV-XV of FIG. In addition, the optical axis B2 of the laser light emitted from the lower laser light source is emitted toward the outer surface of the sack portion 21 from the downstream side of the hole, and is rotated about the center of radius C of the concave surface 21a as a center (FIG. 15, see arrow A2).
The injection hole 20 is drilled in the hole vertical direction, that is, in both directions. By doing so, the dimensional accuracy on the downstream side of the injection hole 20 can be improved. Further, if the processing order is such that the injection hole 20 is opened from the upstream side of the injection hole and then the injection hole 20 is opened from the downstream side of the injection hole, the spatter and dross inside the nozzle chip 2 are reduced and the upstream and downstream sides of the injection hole 20 are reduced. In both cases, dimensional accuracy is improved.

In the case where the injection hole 20 is laser-processed from both directions, as shown in the sectional view of FIG. 16 and the sectional view taken along line XVII-XVII of FIG. The laser beam can be emitted from the upstream side of the hole toward the hemispherical concave surface 21a and moved parallel to the slit direction (see arrow A3 in FIG. 17).

Second Embodiment A second embodiment will be described with reference to FIG. The second embodiment and the following third embodiment are modified from the joint surface between the valve seat 1 and the nozzle tip 2 of the first embodiment. Omitted. In the fuel injection nozzle shown in a partial front sectional view in FIG.
The outer diameter of the nozzle tip 2 is smaller than that of the first embodiment.

A substantially cylindrical ridge 12 is formed on the outer periphery of the lower end of the valve seat 1, so that a stepped surface 13 is formed on the inner periphery. The inner peripheral surface of the ridge 12 is formed as a cylindrical surface that is in sliding contact with the outer peripheral surface of the nozzle tip 2. By the stepped surface 13, a recessed portion (with the same reference numeral as the stepped surface) 13 that can be engaged with the nozzle tip 2 is formed in the valve seat 1. In addition,
The outer peripheral portion of the nozzle tip 2 which engages with the concave portion 13 of the valve seat 1 corresponds to the convex portion (reference numeral 2a) in the present invention.

The convex portion 2a of the nozzle tip 2 is engaged with the concave portion 13 of the valve seat 1, and the inner peripheral portion of the end face of the convex ridge portion 12 of the valve seat 1 and the corresponding nozzle tip 2
Are joined to each other by laser welding 4 or the like.

According to the fuel injection nozzle, the engagement between the concave portion 13 of the valve seat 1 and the convex portion 2a of the nozzle tip 2 makes it easy to ensure coaxiality when the valve seat 1 and the nozzle tip 2 are joined. Can be. In the second embodiment, the engaging means according to the present invention is constituted by the concave portion 13 of the valve seat 1 and the convex portion 2a of the nozzle tip 2.

Third Embodiment A third embodiment will be described with reference to FIG. In the fuel injection nozzle shown in the partial front sectional view of FIG. 19, the outer peripheral surface of the lower end portion of the valve seat 1 is formed by a tapered surface 15, and the distal end portion is formed as a convex portion (reference numeral 1 a is attached). I have.

On the outer periphery of the upper end of the nozzle tip 2,
The stepped surface 24 is formed on the inner peripheral surface by forming the substantially inverted conical cylindrical ridge 23. Ridge 2
The inner peripheral surface of the valve seat 3 is formed as a tapered surface (symbol omitted) in surface contact with the tapered surface 15 of the valve seat 1. The stepped surface 24 forms a concave portion (same as the stepped surface with the same reference numeral) 24 that can be engaged with the convex portion 1 a of the valve seat 1 in the nozzle tip 2.

The concave portion 24 of the nozzle tip 2 and the convex portion 1a of the valve seat 1 are engaged with each other, and the leading edge of the convex ridge portion 23 of the nozzle tip 2 and the corresponding peripheral edge of the tapered surface 15 of the valve seat 1. The parts are joined by laser welding 4 or the like.

According to the fuel injection nozzle, the coaxiality at the time of joining the valve seat 1 and the nozzle tip 2 can be easily ensured by the engagement between the projection 1a of the valve seat 1 and the recess 24 of the nozzle tip 2. Can be. In the third embodiment, the protrusion 1a of the valve seat 1 and the recess 24 of the nozzle tip 2 constitute the engagement means according to the present invention.

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 shape of the injection hole 20 is not limited to the slit shape, and may be a circle, an oval, a polygon, or the like. Further, the number and the formation position of the injection holes 20 are appropriately selected, and are not limited to the above. In addition, the shapes, numbers, formation positions, and the like of the protrusions and recesses of the engagement means are appropriately selected, and are not limited to those described above. Further, the present invention relates to a fuel injection nozzle in a fuel injection valve used for fuel supply of an internal combustion engine, but can be diverted to supply a fluid instead of fuel.

[0033]

According to the fuel injection nozzle of the present invention, it is possible to obtain an injection hole having an arbitrary injection hole shape suitable for improving the performance of an internal combustion engine in a short time with good measurement accuracy.

[Brief description of the drawings]

FIG. 1 is a partial front sectional view of a fuel injection nozzle according to a first embodiment.

FIG. 2 is a partial front sectional view of a valve seat.

FIG. 3 is a front sectional view of a nozzle tip.

FIG. 4 is a plan view of a nozzle tip.

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

FIG. 6 is a plan view showing a material of a nozzle tip.

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

FIG. 8 is a plan view showing a material of a nozzle tip after a sack portion is formed.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 8;

FIG. 10 is a plan view showing a material of a nozzle tip after forming a nozzle hole.

11 is a sectional view taken along line XI-XI in FIG.

FIG. 12 is a cross-sectional view showing a processing direction of laser processing.

FIG. 13 is a sectional view taken along line XIII-XIII of FIG. 12;

FIG. 14 is a cross-sectional view showing another example of a processing direction of laser processing.

FIG. 15 is a sectional view taken along line XV-XV in FIG. 14;

FIG. 16 is a cross-sectional view showing another example of a processing direction of laser processing.

FIG. 17 is a sectional view taken along line XVII-XVII in FIG. 16;

FIG. 18 is a partial front sectional view of a fuel injection nozzle according to a second embodiment.

FIG. 19 is a partial front sectional view of a fuel injection nozzle according to a third embodiment.

FIG. 20 is a partial front sectional view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Valve seat 10 Valve hole 11 Seat part 2 Nozzle tip 20 Injection hole 3 Valve

Claims (4)

[Claims] 1. A valve seat having a valve hole in which a valve is slidably provided and a seat portion on which the valve is seated, and a nozzle having an injection hole which is joined to the valve seat and ejects fuel flowing through the valve hole. A fuel injection nozzle comprising: a tip; and an injection hole of the nozzle tip formed by laser processing from a hole upstream side. 2. The fuel injection nozzle according to claim 1, wherein the injection hole of the nozzle tip is laser-processed from the downstream side of the hole. 3. The fuel injection nozzle according to claim 1, wherein an engagement means comprising a mutually engageable convex portion and a concave portion is provided between the joining surfaces of the valve seat and the nozzle tip. 4. The fuel injection nozzle according to claim 1, wherein both the valve seat and the nozzle tip are made of metal.