JPH0589867U - Fuel injection valve - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] To provide a fuel injection valve capable of reducing wear due to contact between the needle valve and the seat portion of the valve seat. [Structure] Only the seat portion 10a of the needle valve 10,
Alternatively, the seat portion of the valve seat 14 is also formed by a part of the curved surface. Alternatively, a sphere can be attached to the tip of the needle valve. Further, a flange 16 that forms a predetermined clearance with the inner wall of the valve seat is provided on the upstream side of the seat portion of the needle valve. In the above injection valve, the needle valve guide portion formed on the upstream side of the seat portion of the needle valve without flattening and a fuel passage inside the needle valve are provided between the seat portion and the guide portion. Wear caused on the valve seat tapered surface 14a by pressing the needle valve 10 is reduced. Further, the flange 16 makes it possible to make the fuel passage area upstream of the fuel seal portion constant, reduce variations in flow rate, and improve flow rate accuracy.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel injection valve used in an internal combustion engine, and more particularly to a fuel injection valve that prevents flow rate deterioration and improves durability reliability.

[0002]

[Prior Art]

 FIG. 5 is a vertical cross-sectional view of an example of a conventional electromagnetic fuel injection valve. Fuel flows into the electromagnetic fuel injection valve in the direction of arrow A parallel to the central axis.

In FIG. 1, a foreign matter removing strainer 19 having a filter net 18 is attached to the fuel inlet.

A hollow pipe 2 for supplying fuel, which is also made of a magnetic material, is fitted inside a housing 1 made of a magnetic material and formed in a tubular shape. In the space formed between the housing 1 and the pipe 2, a solenoid coil (hereinafter, simply referred to as a coil) 4 wound around a bobbin 3 is housed so as to surround the pipe 2. ing.

A coil spring 12 and a pipe-shaped spring stopper 13 are inserted into the pipe 2, and the spring stopper 13 is provided at a position such that the force of the coil spring 12 pressing the movable iron core 9 is appropriate. It is fixed to the pipe 2.

A valve seat 14 including a needle valve (hereinafter simply referred to as “valve”) 10 is disposed at the tip of the housing 1, and the valve seat 14 is provided with the nozzle 17 at the open end of the housing 1. It has been crimped.

The valve 10 is regulated by the valve stopper 21 to have a constant reciprocating motion corresponding to the valve opening degree. The valve 10 has guide portions 30a and 30b that slide with the inner wall of the valve seat 14 to define the position in the valve seat 14 in the direction perpendicular to the reciprocating movement. It has a cylindrical shape to improve wear resistance. Each of the guide portions 30a and 30b is provided with four flat surfaces as fuel passages.

At the rear end of the housing 1, the flange 2 a of the pipe 2 is crimped at the open end of the housing 1. A connector 5 made of a nonmagnetic material such as resin is fixed to the upper portion of the flange portion 2a, and a terminal 6 electrically conductively connected to the electromagnetic coil 4 is embedded in the connector 5.

In such a configuration, the movable iron core 9 is pressed by the spring 12 at all times (when the coil 4 is not energized), and fuel injection from the injection port 15 is blocked. FIG. 5 shows a state in which the coil 4 is not energized.

The fuel filtered by the strainer 19 passes through the central portion of the spring stopper 13 and is supplied into the valve seat 14 through the hollow hole of the movable iron core 9.

When the coil 4 is energized, the movable iron core 9 is attracted to the lower end of the pipe 2 against the repulsive force of the spring 12, so that the valve 10 separates from the valve seat 14 and is placed inside the valve seat 14. The supplied fuel is injected from the injection port 15 to the nozzle 17.

[0012]

[Problems to be solved by the device]

 Problems of the electromagnetic fuel injection valve having the above structure will be described with reference to FIG. Note that FIG. 6 shows a sectional view of a part of the fuel discharge portion of FIG. 5 that are the same as those in FIG. 5 indicate the same items.

Both the valve seat 14 and the needle valve 10 shown in the figure ensure high hardness. Then, when the needle valve 10 is turned on and off, the edge portion of the edge sheet portion 10c of the needle valve presses the valve seat tapered surface 14a to seal it. At that time, since the load is concentrated on one point of the edge portion, when the number of times of fuel injection is increased, the valve seat tapered surface 14a is worn and the tapered surface 14a becomes a rough surface. Therefore, there is a problem in that the needle valve 10 is caught on the rough surface portion during operation, which delays the response of the valve.

Further, when the operation of the needle valve 10 is repeated, the sliding surfaces (guide portions 30a, 30b) on the upstream side of the seal portion are also worn, and the fuel passage area varies. Therefore, there is a problem that the flow rate varies when the fuel is discharged.

An object of the present invention is to solve the above-mentioned problems and to provide a fuel injection valve capable of reducing wear at a contact portion between a needle valve and a valve seat.

[0016]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention is characterized in that the edge seat portion of the needle valve is formed by a part of a curved surface. Another feature is that a flange that forms a predetermined clearance with the inner wall of the valve seat is provided on the upstream side of the seat portion of the needle valve.

[0017]

[Action]

 According to the above configuration, it is possible to reduce the bite wear on the tapered surface of the valve seat and prevent the tapered surface from becoming a rough surface. As a result, it is possible to prevent the needle valve from being caught in the valve seat during operation of the needle valve, and prevent delay in response and deterioration of flow rate.

Further, by providing the flange, the fuel passage area upstream of the fuel seal portion can be made constant. As a result, the flow of fuel on the downstream side of the flange becomes uniform, uneven distribution of fuel in the discharge spray can be prevented, and flow rate accuracy can be improved.

[0019]

【Example】

 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of a part of a fuel injection valve according to a first embodiment of the present invention.

In FIG. 1, 10 is a needle valve, and 10 a is a high hardness needle valve sheet portion. Further, 14 is a valve seat, 14a is a highly hard valve seat taper surface, and 16 is a flange.

In this embodiment, the seat portion 10a of the needle valve 10 is formed in a spherical shape.

With this configuration, when the seat portion 10a of the needle valve 10 presses the valve seat tapered surface 14a, the bite wear of the seat portion 10a into the valve seat tapered surface 14a is reduced. As a result, it is possible to prevent the tapered surface 14a from becoming a rough surface, and it is possible to prevent the needle valve 10 from being caught during operation. Therefore, the response delay of the needle valve can be reduced, and the flow rate deterioration can be prevented.

Further, in this embodiment, the flange 16 is provided between the seat portion 10a of the needle valve and the needle valve guide portion 30a (see FIG. 5). Therefore, the fuel passage area on the upstream side of the seat portion 10a of the needle valve becomes constant. As a result, the flow of fuel on the downstream side of the flange 16 is made uniform, uneven distribution of fuel in the discharge spray is prevented, and flow rate accuracy is improved.

Next, a second embodiment of the present invention will be described with reference to FIG.

Similar to FIG. 1, FIG. 2 shows a partial cross-sectional view of the fuel injection valve. 14b in the drawing is a seat portion of a valve seat having high hardness.

The present embodiment is characterized in that not only the seat portion 10a of the needle valve but also the seat portion 14b of the valve seat has a spherical shape. Here, if the spherical shape of the seat portion 10a of the needle valve 10 is the diameter α and the spherical shape of the seat portion 14b of the valve seat 14 is the diameter β, then each of the spherical shapes is such that α <β is satisfied. It is configured.

According to the configuration of the present embodiment, as in the first embodiment, the bite wear of the seat portion 10a of the needle valve 10 into the valve seat tapered surface 14a is reduced. Further, in this embodiment, when the fuel is sealed, the spaces on both sides of the annular contact portion are narrowed, so that the fuel sealing property is improved.

Next, a third embodiment of the present invention will be described with reference to FIG.

Similar to FIG. 1, FIG. 3 shows a sectional view of a part of the fuel injection valve. In the figure, 20 is a high hardness sphere, and 10b is a sheet portion of the sphere 20.

The present embodiment is characterized in that the sphere 20 is attached to the tip of the needle valve 10.

According to the present embodiment, when the needle valve 10 is actuated, the spherical body 20 presses the tapered surface 14a of the valve sheet, so that the seat portion 10b of the needle valve 10 is the same as in the first embodiment. It is possible to reduce the bite wear of the valve seat tapered surface 14a. Since the sphere 20 need only be fixed to the tip of the needle valve 10, the seat portion 10b of the needle valve 10 can be easily produced.

FIG. 4 is a sectional view showing a fourth embodiment of the present invention, in which 11 is a fuel supply hole connected from a fuel passage, and 30c is a guide portion of a needle valve.

In the present embodiment, the fuel passage 80 is arranged in the needle valve 10, and the fuel supply hole 11 connected to the fuel passage 80 is buried upstream of the flange 16. Therefore, the fuel passage which is flattened in the conventional guide portion 30a (see FIG. 5) is unnecessary, and the cylindrical guide portion 30c which is not flattened can be used.

Since the present embodiment has the above-described configuration, the guide portion 30c of the present embodiment is less likely to be unevenly worn as compared with the conventional guide portion having the flattened fuel passage. Therefore, the clearance between the flange 16 and the valve seat 14 can be kept uniform. As a result, the flow of fuel on the downstream side of the flange 16 is made uniform, uneven distribution of fuel in the discharge spray is prevented, and flow rate accuracy is improved.

[0036]

[Effect of the device]

 As is apparent from the above description, the present invention achieves the following effects.

(1) The wear caused on the valve seat tapered surface by pressing the needle valve is reduced. As a result, the needle valve can be prevented from being caught on the rough surface of the worn portion, deterioration of the flow rate can be prevented, and durability and reliability can be improved.

(2) Since the wear can be reduced, the uneven distribution of the fuel in the discharge spray can be prevented. That is, the density of the injected fuel can be made uniform.

(3) According to the invention of claim 4, the fuel passage area upstream of the fuel seal portion can be made constant, the variation in the flow rate can be reduced, and the flow rate accuracy can be improved.

[Brief description of drawings]

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

FIG. 2 is a sectional view of an electromagnetic fuel injection valve according to a second embodiment of the present invention.

FIG. 3 is a sectional view of an electromagnetic fuel injection valve according to a third embodiment of the present invention.

FIG. 4 is a sectional view of an electromagnetic fuel injection valve according to a fourth embodiment of the present invention.

FIG. 5 is a vertical sectional view of an example of a conventional electromagnetic fuel injection valve.

6 is a configuration diagram of a part of FIG.

[Explanation of symbols]

10 ... Needle valve, 10a ... Needle valve seat, 10b ... Spherical needle valve seat, 1
0c ... edge seat of needle valve, 11 ... fuel supply port, 14 ... valve seat, 14a ... valve seat tapered surface, 14b ... valve seat seat, 16 ... flange, 20 ... sphere, 30c ... needle valve guide, 8
0 ... Fuel passage.

Claims (4)

[Scope of utility model registration request] Claim: What is claimed is: 1. A needle valve seat is brought into contact with a tapered surface formed on the inner surface of the valve seat to prevent fuel injection, and the needle valve seat is separated from the tapered surface. In the fuel injection valve for injecting, the fuel injection valve is formed by a part of a curved surface of a peripheral portion of a seat portion of the needle valve. 2. The fuel injection valve according to claim 1, wherein a surface of the tapered surface facing the needle valve seat portion has a curvature larger than a curvature of a peripheral portion of the seat portion of the valve seat. A fuel injection valve characterized in that the fuel injection valve is configured by a section. 3. The fuel injection valve according to claim 1, wherein the needle valve is formed on an upstream side of a seat portion of the needle valve.
A cylindrical guide which is not flattened, a fuel passage formed inside the needle valve, and an outlet of the fuel passage provided between a seat portion of the needle valve and the cylindrical guide. A fuel injection valve characterized in that. 4. A fuel valve is provided by contacting a seat portion of a needle valve with a tapered surface formed on the inner surface of a valve seat to prevent fuel injection and separating the seat portion of the needle valve from the tapered surface. In the fuel injection valve for injecting the fuel injection valve, a flange is formed upstream of a seat portion of the needle valve so as to have a predetermined clearance with an inner wall of the valve seat.