JPH0450464A - fuel injector - Google Patents

Abstract

PURPOSE:To fix a nozzle plate and a jet nozzle to each other uniformly and strongly by engaging the nozzle plate in a circular recess formed in a forward end surface of time jet nozzle, and welding an outer edge part to the circumferential wall of the circular recess. CONSTITUTION:A circular recess 22 opening outward is formed in a forward end surface 21D of a jet nozzle 21. A nozzle plate 23 is engaged in the circular recess 22, and an outer edge part 23B of the nozzle plate 23 is welded with the circumferential wall of the circular recess 2?. The nozzle plate 23 can thus be fixed to the jet nozzle 21 uniformly along the whole circumference. The fixture strength of the nozzle relate 23 to the jet nozzle 21 can therefore be increased largely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fuel injector suitable for use in an electronically controlled fuel injection device for, for example, an automobile engine.

[Prior Art] FIGS. 4 to 6 show fuel injectors according to the prior art.

In the figure, 1 is an injector main body formed in a stepped cylindrical shape, 2 is a casing constituting the injector main body 1, and the casing 2 is a hollow outer cylinder part 2A in which a fuel flow port 3 is formed in the radial direction. It consists of a lid part 2B formed on the upper end side in the axial direction of the outer cylinder part 2A, and a hollow cylindrical core part 2c formed to protrude and penetrate through the center of the lid part 2B. Reference numeral 4 designates a stepped cylindrical holder that constitutes the injector body 1 together with the casing 2. The upper end of the holder 4 is fitted and fixed to the lower end of the casing 2, and a needle valve 8, which will be described later, is attached to the inner periphery of the lower end. A substantially U-shaped or C-shaped plate stopper 5 for regulating the valve opening position is fitted and fixed together with an injection nozzle 6, which will be described later.

Reference numeral 6 designates an injection nozzle formed into a hollow cylindrical body whose upper end side in the axial direction is fitted and fixed to the holder 4 with the plate stopper 5 sandwiched therebetween, and the injection nozzle 6 has a large diameter extending in the axial direction. A guide hole 6A, an injection port 6B opening on the lower side of the injection nozzle 6, and a concave conical valve seat 6C located between the injection port 6B and the guide hole 6A are formed. A nozzle plate 7, which will be described later, is fixed to the tip surface 6D by laser welding.

7 indicates a substantially disc-shaped nozzle plate, and in the center of the nozzle plate 7, for example, four injection holes 7A, 7A, . . . (see FIG. 6) communicating with the injection port 6B are arranged at predetermined intervals. Each injection hole 7A is configured to inject fuel in different directions. As shown in FIGS. 5 and 6, the upper surface 7C of the nozzle plate 7 is fixed to the tip surface 6D of the injection nozzle 6 through an annular welded portion 7B formed by laser welding.

Reference numeral 8 indicates a needle valve that is slidably provided in the injection nozzle 6 in the axial direction, and the needle valve 8 is arranged in the guide hole 6A.
A valve shaft 8A that slides inside the valve shaft 8A, a large diameter portion 8B formed on the upper end side of the valve shaft 8A and fitted into an anchor 10, which will be described later, and a valve shaft 8A located below the large diameter portion 8B. A stopper portion 8C is formed in a flange shape in the middle and abuts against the plate stopper 5, and a stopper portion 8C is formed on the lower end side of the valve shaft 8A and is formed in the valve seat 6C.
It is comprised of a convex conical valve portion 8D that is seated and separated from the valve portion 8D. A fuel flow path 9 is formed between the needle valve 8 and the injection nozzle 6.

Reference numeral 10 indicates an anchor fixed to the large diameter portion 8B of the needle valve 8 by means such as laser welding while opposing the end surface of the core portion 2C of the casing 2. Reference numeral 11 indicates an anchor fixed within the core portion 2C while opposing the anchor 10. The adjustment rod 11 is shown as an inserted spring receiving member, and a valve spring 12 is disposed between the adjustment rod 11 and the anchor 10, and the valve spring 12 always moves the needle valve 8 in the closing direction. It is energizing.

Reference numeral 13 denotes an electromagnetic coil that is fitted between the outer cylinder part 2A and the core part 2C of the casing 2 and constitutes an electromagnetic actuator together with the core part 20 and the like. When a signal is input, it is excited,
The anchor lO is moved to the core part 2C against the spring force of the valve spring 12.
The needle valve 8 is opened by suctioning the tip of the needle.

Reference numeral 14 indicates a connector provided on the outside of the lid portion 2B of the casing 2. The connector 14 has a pair of terminal bins 15 (only one is shown), and each terminal bin 15 is connected to the electromagnetic coil 13.
is connected to. Reference numeral 16 denotes a filter fitted into the outer cylinder portion 2A of the casing 2 so as to cover the fuel flow port 3.

The conventional fuel injector has the above-mentioned configuration, and its operation will be explained next.

First, the fuel from the fuel pump is supplied to the fuel pipe (not shown).
The fuel is supplied into the casing 2 from the fuel flow port 3 via the filter 16, and flows from the outer periphery of the anchor 10 through the plate stopper 5 and into the fuel flow path 9 between the injection nozzle 6 and the needle valve 8.

Then, when power is supplied to the electromagnetic coil 13 via the terminal bin 15 in response to an injection signal from a control unit (not shown), the anchor 10 is attached to the lower end surface of the core portion 2C of the casing 2 together with the needle valve 8. It is attracted against the spring force. This causes the needle valve 8 to move to the valve seat 6C.
When the valve is opened and the nozzle 6 is unseated, fuel is injected from the injection port 6B of the injection nozzle 6 to the outer part of the nozzle plate 7 through each injection hole 7A. And each injection hole 7A of the nozzle plate 7
The fuel from the engine is injected in different directions, improving the injection pattern and improving atomization and mixing with the intake air.

On the other hand, when power supply is stopped, the electromagnetic coil 13 is demagnetized and the needle valve 8 is seated on the valve seat 6C by the spring force of the valve spring 12, thereby stopping fuel injection.

[Problems to be Solved by the Invention] In the above-mentioned prior art, the nozzle plate 7 is fixed to the tip surface 6D of the injection nozzle 6 by laser welding to form an annular welded part 7B. The fixing work involves attaching the nozzle plate 7 to the tip surface 6 of the injection nozzle 6.
While pressing the nozzle plate 7 so as to cover it, a laser beam is irradiated onto the surface of the nozzle plate 7, and the upper surface 7C of the nozzle plate 7 and the tip surface 6D of the injection nozzle 6 are melted in an annular shape along the welded portion 7B. However, it is difficult to uniformly fix the nozzle plate 7 to the injection nozzle 6 with high fixing strength, and weld gaps and cracks occur in the circumferential direction of the welded part 7B due to the density of the laser beam. The problem is that it is easy.

For this reason, in the prior art, when fuel is injected from the injection nozzle 6 through the injection port 6B, the nozzle plate 7 is distorted due to this pressure and the fuel injection pattern by each injection hole 7A is distorted, and the injection nozzle 6 and the nozzle plate There is a problem in that the sealing performance between the nozzle plate 7 and the nozzle plate 7 tends to deteriorate, and a part of the fuel from the injection port 6B of the injection nozzle 6 leaks in the radial direction of the nozzle plate 7 through the weld gap or crack in the weld part 7B. In addition, there is a problem in that the nozzle plate 7 peels off from crack occurrence locations due to the injection pressure during fuel injection, and the nozzle plate 7 falls from the injection nozzle 6 due to deterioration over time.

It is also possible to weld the nozzle plate 7 to the injection nozzle 6 at the outer edge 7D of the nozzle plate 7, as shown in FIG. There is a problem that the nozzle plate is easily bent due to the injection pressure when fuel is injected from the injection port 6B, and the injection pattern of the fuel injected from each injection hole 7A of the nozzle plate 7 is deteriorated. Since the outer edge 7D of the plate 7 is bent by a press or the like, there is a problem in that the precision of the end face is low and it is difficult to uniformly fix the plate 7 by laser welding.

The present invention has been made in view of the problems of the prior art described above, and the present invention can uniformly and firmly fix the nozzle plate and the injection nozzle, and improves the sealing performance between the nozzle plate and the injection nozzle. It is an object of the present invention to provide a fuel injector which is capable of improving the performance of the fuel injection device, and is also capable of stabilizing the injection pattern by preventing deflection of the nozzle plate during fuel injection.

[Means to solve the problem]

In order to solve the above-mentioned problems, the feature of the configuration adopted by the present invention is that an annular recess that opens outward is formed in the tip surface of the injection nozzle, a nozzle plate is fitted into the annular recess, and the nozzle The outer edge of the plate is welded to the peripheral wall of the annular recess of the injection nozzle.

[Effect]

With the above configuration, while the nozzle plate is fitted into the annular recess, the outer edge of the nozzle plate can be easily welded to the peripheral wall of the annular recess along the entire circumference, and the welding strength can be significantly increased. can.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 3. Note that the same reference numerals are given to the same components as those of the prior art described above, and the explanation thereof will be omitted.

Thus, FIGS. 1 and 2 show a first embodiment of the present invention.

In the figure, reference numeral 21 indicates an injection nozzle, and the injection nozzle 21 has a guide hole 2, which is similar to the injection nozzle 6 described in the prior art.
1A, an injection port 21B, and a valve seat 21C, an annular recess 22, which will be described later, is formed in the tip surface 21D of the injection nozzle 21.

Reference numeral 22 denotes an annular recess that is recessed in the center of the tip surface 21D of the injection nozzle 21 and opens downward to surround the injection port 21B.The annular recess 22 has a larger diameter than the injection port 21-B, and The nozzle 21 is formed so as to leave an annular flat surface portion 21D+ on the tip surface 21D. A nozzle plate 23, which will be described later, is fitted into the annular recess 22.

Reference numeral 23 indicates a nozzle plate formed in the shape of a flat disk, and the nozzle plate 23 has, for example, four injection holes 23A, 23A, similar to the nozzle plate 7 described in the prior art.
, ... (see Fig. 2) are bored on the inner circumferential side, but the nozzle plate 23 fits into the annular recess 22 (with an outer diameter approximately equal to the diameter of the annular recess 22). The nozzle plate 23 is formed into a disk shape with a small diameter. After the nozzle plate 23 is inserted into the annular recess 22 with a portion protruding, the outer edge 23B is shaped into an annular shape by irradiating a laser beam from an oblique direction. The entire circumference of the recess 22 is welded to the annular flat surface portion 21D1.

Here, the outer diameter of the nozzle plate 23 is large enough to prevent each injection hole 23A from being deformed due to heat effects when the outer edge 23B of the nozzle plate 23 is welded to the peripheral wall of the annular recess 22, and the injection nozzle 21 injection port 21B
The nozzle plate 23 is made as small as possible so that the injection pattern of the fuel injected from each injection hole 23A is not distorted by the injection pressure when the fuel is injected from each injection hole 23A.

The fuel injector according to this embodiment has the configuration described above, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, an annular recess 22 that is coaxial with the injection port 21B and opens downward is formed on the tip surface 21D of the injection nozzle 21, and a nozzle plate whose outer diameter is made as small as possible is installed in the annular recess 22. 23, and nozzle plate 2.
Since the outer edge 23B of the nozzle plate 2 was welded to the circumferential wall of the annular recess 22 from an oblique direction by laser welding, the nozzle plate 2
3 can be fixed uniformly to the injection nozzle 21 over the entire circumference.

Thus, according to this embodiment, the adhesion strength between the nozzle plate 23 and the injection nozzle 21 can be significantly increased, the sealing performance between the nozzle plate 23 and the injection nozzle 21 can be improved, and cracks and Various effects such as being able to effectively prevent the occurrence of welding gaps, stabilizing the fuel injection pattern from each injection hole 23A, and making it possible to obtain a desired injection pattern are achieved.

Next, FIG. 3 shows a second embodiment of the present invention, and the feature of this embodiment is that the nozzle plate is arranged in an annular shape so that the lower surface of the nozzle plate and the tip surface of the injection nozzle are located on the same plane. This is due to the fact that it is fitted and fixed in the recess.

In the figure, numeral 31 indicates an annular recess, and the annular recess 31 opens downward, leaving an annular flat surface 21D1 on the distal end surface 2LD of the injection nozzle 21, similar to the annular recess 22 described in the first embodiment. However, the depth of the annular recess 31 is approximately equal to the thickness of the nozzle plate 23. After fitting the nozzle plate 23, the annular recess 31 is welded by irradiating a laser beam or the like over the entire circumference between the outer edge 23B of the nozzle plate 23 and the annular flat surface 21D. It has become.

Thus, this embodiment configured in this manner can also provide substantially the same effects as those of the first embodiment.

In each of the above embodiments, the outer edge 23B of the nozzle plate 23 is welded to the peripheral wall of the annular recess 22 (31) by laser welding, but instead of this, arc welding, brazing, etc. Other welding means may be used to secure the nozzle plate 23.

[Effects of the Invention] As described in detail above, according to the present invention, an annular recess opening outward is formed in the tip surface of the injection nozzle, a nozzle plate is fitted into the annular recess, and the nozzle plate is Since the outer edge is welded to the peripheral wall of the annular recess of the injection nozzle, the nozzle plate can be fixed uniformly to the injection nozzle over the entire circumference, and the adhesion strength between the nozzle plate and the injection nozzle can be greatly increased. can. Therefore, not only can the sealing performance between the nozzle plate and the injection nozzle be improved, but also the occurrence of cracks and weld gaps can be effectively prevented, and the fuel injection pattern from each injection hole can be stabilized. etc., various effects can be achieved.

[Brief explanation of the drawing]

Figures 1 and 2 show a first embodiment of the present invention, with Figure 1 being an enlarged vertical sectional view of the main parts of the fuel injector, Figure 2 being a plan view of the nozzle plate, and Figure 3 being a top view of the nozzle plate. 1 is an enlarged sectional view of a main part of a fuel injector showing a second embodiment of the present invention, and FIGS. 4 to 6 show a conventional technique,
FIG. 4 is a longitudinal cross-sectional view of the fuel injector, FIG. 5 is a vertical cross-sectional view showing an enlarged main part of FIG. 4, and FIG. 6 is a plan view of the nozzle plate. 1... Injector body, 8... Needle valve, 13
...Electromagnetic coil (electromagnetic actuator), 21...
Injection nozzle, 21B... Injection port, 22.31... Annular recess, 23... Nozzle plate, 23A... Injection hole, 23B... Outer edge. Patent applicant Agent: Japan Electronics Co., Ltd.
Patent Attorney Kazuhiko Hirose Diagram

Claims (1)

[Claims] an injector main body; an injection nozzle provided on one end side of the injector main body and having an injection port formed on the tip side;
A needle valve is slidably provided in the injection nozzle to open and close the injection port of the injection nozzle, and a needle valve is provided in the injector main body and opens the needle valve by receiving power from an external part. In the fuel injector, the fuel injector includes an electromagnetic actuator that causes the injection nozzle to move, and a nozzle plate that is provided on the tip side of the injection nozzle and has a plurality of injection holes that communicate with the injection port of the injection nozzle. A fuel injector characterized in that an annular recess is formed that opens outward, the nozzle plate is fitted into the annular recess, and an outer edge of the nozzle plate is welded to a peripheral wall of the annular recess of the injection nozzle.