JPH085334Y2 - Fuel injector - Google Patents

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 such as an automobile engine.

[Conventional technology]

6 to 8 show a conventional fuel injector.

In the figure, 1 is an injector main body formed in a stepped tubular shape, 2 is a casing that constitutes the injector main body 1, and the casing 2 is a hollow outer tubular portion 2A in which a fuel flow port 3 is formed in the radial direction. And a lid portion 2B formed on the axially upper end side of the outer tubular portion 2A, and a hollow tubular core portion 2C projectingly formed so as to penetrate through the center of the lid portion 2B.
Reference numeral 4 denotes a stepped cylindrical holder that constitutes the injector main body 1 together with the casing 2. The holder 4 has an upper end side fitted and fixed to the lower end side of the casing 2, and a needle valve 9 described later on the inner circumference of the lower end side. 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 described later.

Reference numeral 6 denotes an injection nozzle formed in the shape of a hollow cylinder, which is fitted and fixed to the holder 4 with the upper end side in the axial direction sandwiching the plate stopper 5, and the injection nozzle 6 has a large diameter extending in the axial direction. A guide hole 6A, an injection port 6B that opens below the injection nozzle 6, and a concave conical valve seat 6C that is located between the injection port 6B and the guide hole 6A.
A nozzle plate 7, which will be described later, is fixed to the lower end surface 6D by laser welding.

Reference numeral 7 designates a substantially disk-shaped nozzle plate, and four nozzle holes 7A, 7A, ... (See FIG. 8), which communicate with the nozzle 6B, are formed in the center of the nozzle plate 7 at predetermined intervals. Each of the injection holes 7A is provided to inject fuel in different directions. As shown in FIGS. 7 and 8, the nozzle plate 7 is an annular welded portion 7B formed by laser welding, and its upper surface 7C is the lower end surface of the injection nozzle 6.
It is stuck to 6D.

Reference numeral 8 denotes a protector formed of a synthetic resin material in a substantially cylindrical shape. The protector 8 is attached to the lower end side of the injection nozzle 6 so as to cover the nozzle plate 7.

Reference numeral 9 denotes a needle valve provided in the injection nozzle 6 so as to be slidable in the axial direction, and the needle valve 9 is the guide hole 6A.
A valve shaft 9A that slides inside, and is formed on the upper end side of the valve shaft 9A,
A large diameter portion 9B into which an anchor 11 described later is fitted, and the large diameter portion 9B
A stopper portion 9C, which is located below the valve shaft 9A, is formed in the middle of the valve shaft 9A and has a flange shape, and is in contact with the plate stopper 5.
It is composed of a concave conical valve portion 9D which is formed on the lower end side of 9A and which is seated on and off the valve seat 6C. A fuel flow path 10 is formed between the needle valve 9 and the injection nozzle 6.

11 is an anchor fixed to the large diameter portion 9B of the needle valve 9 by means such as laser welding in a state of facing the end surface of the core portion 2C of the casing 2, and 12 is in the core portion 2C while facing the anchor 11. 2 shows an adjusting rod as a spring receiving member that is inserted into the valve. A valve spring 13 is disposed between the adjusting rod 12 and the anchor 11, and the valve spring 13 always closes the needle valve 9 in the valve closing direction. I am biased.

Reference numeral 14 designates a solenoid as an electromagnetic actuator fitted between the outer cylinder portion 2A of the casing 2 and the core portion 2C,
The solenoid 14 is excited when an injection signal is input through the terminal pin 15, and resists the spring force of the valve spring 13 to cause the anchor 11 to move.
The needle valve 9 is operated to open by suctioning the needle valve 9.

Reference numeral 16 denotes a connector provided outside the lid portion 2B of the casing 2, and 17 denotes a filter fitted to the outer cylindrical portion 2A of the casing 2 so as to cover the fuel flow port 3.

The fuel injector of the prior art has the above-mentioned structure, and its operation will be described below.

First, the fuel from the fuel pump is supplied from the fuel flow port 3 to the casing 2 through a fuel pipe (not shown) and a filter 17.
It is supplied into the fuel passage 10 between the injection nozzle 6 and the needle valve 9 from the outer periphery of the anchor 11 through the plate stopper 5. Then, when power is supplied to the solenoid 14 through the terminal pin 15 by an injection signal from a control unit (not shown), the core portion of the casing body 2
Anchor 11 together with needle valve 9 on the lower end surface of 2C
It is sucked against the spring force of 13. As a result, the needle valve 9 is separated from the valve seat 6C and opened, and the injection port of the injection nozzle 6 is opened.
Fuel is injected to the outside from 6B through each injection hole 7A.

On the other hand, when the power supply is stopped, the solenoid 14 is demagnetized, and the needle valve 9 is seated on the valve seat 6C by the spring force of the valve spring 13, so that the fuel injection is stopped.

[Problems to be solved by the device]

By the way, in the above-mentioned conventional technique, the nozzle plate 7
Although the upper surface 7C of the injection nozzle 6 is fixed to the lower end surface 6D of the injection nozzle 6 at the annular welded portion 7B by laser welding as shown in FIG. Since the control method, positioning, etc. are complicated and the irradiation accuracy of the welding beam is reduced, the density of the welding beam is likely to occur, and welding gaps or cracks may occur in the circumferential direction of the welded portion 7B.

Therefore, in the prior art, when the nozzle plate 7 and the injection nozzle 6 are non-uniformly fixed, when the fuel is injected from the injection nozzle 6 through the injection port 6B, the nozzle plate 7 is distorted by this pressure. In addition to the problem that the fuel injection pattern due to each injection hole 7A collapses, the nozzle plate 7 peels off at the cracked portion of the welded portion 7B, etc., and the adhesion strength of the nozzle plate 7 to the injection nozzle 6 decreases. There is.

In addition, 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 welding gaps and cracks in the welded portion 7B, and the engine stops, especially, the wall film flow in the intake pipe. When the engine is started again, the fuel is excessively concentrated, which causes problems such as a decrease in the air-fuel ratio, a poor engine start, and incomplete fuel.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention can uniformly fix the nozzle plate and the injection nozzle by laser welding, and can prevent the formation of welding gaps and cracks at the welded portion. The present invention provides a fuel injector capable of reliably preventing fuel from leaking to the outside, improving the fixing strength of a nozzle plate, and effectively preventing engine start failure and incomplete combustion. .

[Means for solving the problem]

In order to solve the above-mentioned problems, the feature of the configuration adopted by the present invention is that the nozzle plate is fixed to the tip surface of the injection nozzle by a plurality of linear welded portions by laser welding, and each linear welded portion is the nozzle. That is, they intersect each other at both ends so as to surround each injection hole of the plate.

[Action]

With the above configuration, each linear welded part is uniformly formed to suppress the occurrence of welding gaps and cracks, and the periphery of each injection hole of the nozzle plate can be sealed by each linear welded part, which stabilizes the injection pattern during fuel injection. In addition, the nozzle plate can be reliably fixed to the injection nozzle.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. It should be noted that the same components as those of the conventional technique described above are designated by the same reference numerals, and the description thereof will be omitted.

1 to 3 show a first embodiment of the present invention.

In the figure, 21 indicates a nozzle plate, and the nozzle plate
Although 21 is formed with each injection hole 21A almost similarly to the nozzle plate 7 described in the prior art, three linear welded portions 22, 22, by laser welding are formed on the outer peripheral side thereof. It is formed in a substantially triangular shape so as to surround the injection hole 21A, and the upper surface side of the nozzle plate 21 is fixed to the lower end surface 6D of the injection nozzle 6 by the respective linear welding portions 22 (see FIG. 7). . Then, as shown in FIG. 2, each of the linear welded portions 22 linearly irradiates the laser beam in, for example, the arrow A direction to the terminal end 22A, and then linearly irradiates the laser beam from the starting end 22B in the arrow B direction. Formed by this, each straight weld
As shown in the drawing, the linear welded portions 22 and the other linear welded portions 22 whose both ends are adjacent to each other intersect and overlap each other at the terminal end 22A and the starting end 22B to form the weld overlapping portions 23, 23, ... At each vertex of the triangle. Has become. In addition, each linear weld 22 is connected to each injection hole 21.
The welding position is determined so that the distance from A is secured to a predetermined dimension and the heat generated during laser welding does not affect each injection hole 21A by thermal deformation or the like.

The fuel injector according to the present embodiment has the above-mentioned configuration, and its basic operation is not different from that according to the prior art.

Therefore, in this embodiment, each injection hole 21 of the nozzle plate 21 is
Since the upper surface side of the nozzle plate 21 is fixed to the lower end surface 6D of the injection nozzle 6 by each linear welding portion 22 that intersects A at both end portions and surrounds in a substantially triangular shape, laser is used during laser welding. By irradiating the beam in a straight line, each linear weld 22 can be easily formed, the welding work can be simplified, and the laser beam can be made uniform at each linear weld 22, and there are no welding gaps or cracks. It is possible to effectively prevent such occurrence.

Further, as shown in FIG. 3, it is conceivable that instead of each linear welded portion 22, one triangular welded portion 24 is folded back in the arrow C direction at the apex 24A to form a triangular shape. In this case, when the laser beam turns back at each apex 24A, the welding speed becomes relatively slow and it becomes densely overlapped,
Each vertex 24A is excessively irradiated with the laser beam and cracks are likely to occur. Therefore, in this embodiment, as described above, the linear welding portions 22 are formed to prevent the excessive irradiation of the laser beam.

Thus, according to the present embodiment, the nozzle plate 21 and the injection nozzle 6 can be evenly and reliably fixed to each other by laser welding, and it is possible to effectively prevent a welding gap or a crack from being generated in each linear weld portion 22. It is possible to prevent the fuel from leaking out in the radial direction of the nozzle plate, and it is possible to greatly improve the fixing strength of the nozzle plate 21 to the injection nozzle 6, and to stabilize the injection pattern by each injection hole 21A. Various effects such as effective prevention of engine start failure and incomplete combustion can be achieved.

Next, FIG. 3 shows a second embodiment of the present invention. The feature of this embodiment is that each injection hole of the nozzle plate is formed by four linear welded portions, and both ends thereof intersect each other.
It lies in the fact that it has a rectangular shape and is surrounded by it. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the figure, 31 indicates a nozzle plate, and the nozzle plate
Although 31 is formed with each injection hole 31A almost like the nozzle plate 21 described in the first embodiment, four linear welded portions 32, 32, ... Are provided on the outer peripheral side thereof. Each injection hole 31
As it surrounds A, it is formed in a substantially square shape,
The upper surface side of the nozzle plate 31 is fixed to the lower end surface 6D of the injection nozzle 6 by the respective linear welding portions 32. The linear welds 32 are formed by linearly irradiating the laser beam in the same manner as the linear welds 22 described in the first embodiment, and both ends thereof are adjacent to each other. The linear welded portion 32, the end 32A, and the start end 32B intersect and overlap each other as shown in the drawing, and weld overlapping portions 33, 33, ... Are formed at each vertex of the quadrangle. Further, each linear welding portion 32 can secure a predetermined distance from each injection hole 31A to prevent the heat at the time of laser welding from being affected by thermal deformation or the like on each injection hole 31A, and the nozzle plate. The welding position of the 31 is determined so that it can be restrained from being bent and deformed by the pressure of the fuel.

Thus, in this embodiment configured as described above, substantially the same effect as that of the first embodiment can be obtained, but particularly in the present embodiment, between each injection hole 31A and each linear welding portion 32, Since the distances can be made equal, the state of each injection hole 31A due to heat during laser welding can be made uniform,
It is possible to stabilize the fuel injection pattern for a longer period of time.

Further, FIG. 5 shows a third embodiment of the present invention. The feature of the present invention is that each of the linear welded parts 32 according to the second embodiment described above.
In place of the linear welds 41, 41, ... As shown in FIG. Also in this embodiment formed in this way, the same effect as in the second embodiment can be obtained. However, in this case, as compared with the second embodiment, the distance between each injection hole 31A and each linear welding portion 41 becomes shorter, so that each injection hole 31A is more likely to be affected by heat during laser welding. However, since each injection hole 31A is surrounded by each linear weld 41, good sealing performance can be maintained.

[Effect of device]

As described above in detail, according to the present invention, the nozzle plate is fixed to the tip surface of the injection nozzle by a plurality of linear welded portions by laser welding, and each linear welded portion surrounds each injection hole of the nozzle plate. Since each end is crossed with each other like this, each linear weld can be easily formed,
In addition to simplifying the welding work, the laser beam can be made uniform in each linear weld, and the occurrence of welding gaps, cracks, etc. can be effectively prevented. Further, by this, the nozzle plate and the injection nozzle can be fixed uniformly and surely, the periphery of each injection hole of the nozzle plate can be surely sealed by each linear welding portion, and the injection at the time of fuel injection Various effects can be obtained such that the pattern can be stabilized for a long period of time.

[Brief description of drawings]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a plan view of a nozzle plate, FIG. 2 is an explanatory view showing an enlarged linear weld portion, and FIG. 4 is a plan view of the nozzle plate according to the second embodiment of the present invention, and FIG. 5 is a plan view of the nozzle plate according to the third embodiment of the present invention. 8 to FIG. 8 show the prior art, FIG. 6 is a vertical cross-sectional view of the fuel injector, FIG. 7 is a vertical cross-sectional view showing an enlarged main part of FIG. 6, and FIG. 8 is a protector of FIG. FIG. 6 is a plan view of the nozzle plate showing a state in which is removed. 1 ... Injector body, 6 ... Injection nozzle, 6B ... Injection port,
9 ... Needle valve, 14 ... Solenoid (electromagnetic actuator), 21, 31 ... Nozzle plate, 21A, 31A ... Injection hole, 22, 3
2,41… Straight weld.

Claims (1)

[Scope of utility model registration request] 1. An injector main body, an injection nozzle provided at one end side of the injector main body and having an injection port formed at a tip end side, and sliding inside the injection nozzle to open and close the injection port of the injection nozzle. A needle valve that can be provided, an electromagnetic actuator that is provided in the injector body and that opens the needle valve by being supplied with electric power from the outside, and is fixed to the tip end surface of the injection nozzle by laser welding, In a fuel injector including a nozzle plate having a plurality of injection holes communicating with the injection port of the nozzle, the nozzle plate is fixed to a tip end surface of the injection nozzle by a plurality of linear welded portions by the laser welding, Each of the linear welded portions intersects with each other so as to surround each of the injection holes of the nozzle plate. Fuel injector.