JPH0763138A - Fuel injection valve and its manufacture - Google Patents

Abstract

PURPOSE:To provide a fuel injection valve and its manufacture not accompanied by the worsening of responsiveness and groove shape change caused by pressure entering. CONSTITUTION:In the case of a fuel injection valve having a needle valve 5 and a valve body 4, a spiral groove (a flow passage) 6 is formed in the inner periphery of the valve body 4 (a cylindrical collar 1 in the case of the cylindrical collar 1 being furnished). As for its manufacture, a coil-like collar 2 is formed by winding spirally slender materials with a gap between the materials, and this collar 2 is furnished on the inner periphery of the valve body 4 (the cylindrical collar 1). As pressure entering does not accompany, groove deformation due to pressure entering does not occur, and as formation is not made on the needle valve 5 side, there is no need of the needle valve 5 diameter to be enlarged, and the worsening of responsiveness due to weight increase is not generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve of the type in which a swirl (swirl flow or swirl flow) is used to inject fuel and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a fuel injection valve used in a cylinder injection type internal combustion engine, a swirl generation type fuel injection valve is used for stratified combustion, and a swirl is used to inject fuel to atomize the spray. ing. Conventionally, as shown in FIG. 4, a swirl generating structure of a fuel injection valve has a needle valve 15, a valve body 14, and a spiral groove 16 on the outer circumference.
Or a cylindrical collar 11 press-fitted into the inner circumference (for example, Japanese Utility Model Laid-Open No. 60-183268).
Alternatively, it is composed of a needle valve having a spiral groove formed on the outer periphery thereof and a valve body on the outer peripheral side thereof or a collar press-fitted into the valve body.

[0003]

However, in the case where the spiral groove is formed on the outer circumference of the collar, the groove is likely to be deformed when the collar is press-fitted, it is difficult to match the design value, and it is equivalent to press-fitting several times. Therefore, there is a high rate of pressure flash,
There are problems such as. Further, in the case where a groove is formed on the outer circumference of the needle valve, it is necessary to increase the diameter of the needle valve itself, resulting in a large weight and deteriorating responsiveness of the needle valve driven by electromagnetic force or spring force. There is. An object of the present invention is to form a spiral flow path between a needle valve and a needle valve built-in portion of a valve body without causing deformation of the flow path cross section due to press fitting and increasing the diameter of the needle valve. Another object of the present invention is to provide a fuel injection valve and a manufacturing method thereof.

[0004]

To achieve the above object, a fuel injection valve according to the present invention comprises an injection valve of the following (1), and a manufacturing method thereof comprises a method of the following (2). (1) In a fuel injection valve having a needle valve and a valve body containing the needle valve, the inside diameter of the needle valve built-in portion of the valve body is formed larger than the outside diameter of the needle valve, and the valve body A fuel injection valve in which a spiral flow path is formed between the needle valve built-in portion and the needle valve. (2) In a method of manufacturing a fuel injection valve having a needle valve and a valve body containing the needle valve, the inner diameter of the needle valve built-in portion of the valve body is formed to be larger than the outer diameter of the needle valve, and is elongated. A coil-shaped collar is formed by spirally winding a material with a gap between the materials, and the coil-shaped collar is fixed to the needle valve built-in portion of the valve body, and the coil-shaped collar, the valve body, and the needle valve. A method of manufacturing a fuel injection valve that forms a spiral flow path by means of a method.

[0005]

In the fuel injection valve of the above (1), since the spiral groove is formed on the inner peripheral surface side of the valve body, and this portion does not receive the pressure input, the cross sectional deformation of the spiral groove does not occur. . Further, since the spiral groove is formed on the valve body side, the needle valve is not increased in diameter, and the responsiveness is not reduced.
In the above method (2) for manufacturing a fuel injection valve, a coil-shaped collar is formed and attached to and fixed to an inner peripheral surface of a valve body that is preliminarily formed to have a diameter larger than the outer diameter of the needle valve. It is possible to easily form the spiral flow path without the processing difficulty and cost increase such as machining the spiral groove.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel injection valve and a method of manufacturing the same according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 3 shows the tip of the fuel injection valve. In FIG. 3, 5 is a needle valve (also called a poppet valve), and 4 is a valve body containing the needle valve 5. The cylindrical collar 1 may be press-fitted to the inner circumference of the needle valve built-in portion of the valve body 4, and when the cylindrical collar 1 is press-fitted, the cylindrical collar 1 is inserted into the valve body 4.
Regarded as part of. Inside the valve body 4, the needle valve 5 is axially movable, and is normally moved by a spring force in the closing direction and an electromagnetic force in the opening direction. The structure of this drive unit can be the same as that of the drive unit of the conventional fuel injection valve.

The inner diameter of the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted) is formed larger than the outer diameter of the needle valve 5, and the coiled collar 2 is mounted between them. There is a gap that can be created. The coiled collar 2 has a gap between the wound materials, and the gap is provided on the inner peripheral surface of the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted) and the outer peripheral surface of the needle valve 5. A spiral flow path 6 is formed between and. The coiled collar 2 has an outer peripheral surface on the inner peripheral surface of the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted),
It is fixed, for example, by brazing. 3 shows this brazing layer. The inner peripheral surface of the coiled collar 2 can slide on the outer peripheral surface of the needle valve 5. Therefore, the spiral channel 6
Is defined by the inner peripheral surface of the coiled collar 2 and the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted) and the outer peripheral surface of the needle valve 5.

A valve seat 7 is formed at a portion of the valve body 4 where the needle valve 5 abuts or separates in the axial direction, and immediately downstream thereof, the valve body 4 is formed in a dome shape which projects downward.
The injection hole 8 is formed in this dome-shaped portion. The injection hole 8 may be inclined from the fuel injection valve, and the injection angle is not limited to 90 °.

Next, the operation of the fuel injection valve will be described. The swirl imparted when the fuel passes through the spiral flow path 6 is maintained even when the fuel exits the injection hole 8, and the fuel is spread and atomized while spreading due to the centrifugal force of the swirl. This divergence angle is the spray angle. In a conventional fuel injection valve in which a spiral groove is formed on the outer circumference of a cylindrical collar as shown in FIG. 4, the axial end surface of the collar 11 and the valve body 14 are provided.
The swirl is weakened when passing through the passage 13 formed between the inner wall of the lower wall 12 and the inner surface of the lower wall 12. However, as in the present invention, the swirl immediately reaches the valve seat 7 portion immediately after exiting the spiral flow path 6. In the flowing material, the swirl is not weakened and the fuel atomization characteristics are good.

The coiled collar 2 is attached to the inner peripheral surface of the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted), and since that portion is not the press-fitting portion, the coiled collar 2 is mounted. At times, the cross section of the flow path 6 is not distorted by the pressure input. Further, unlike the case where a spiral groove is provided on the outer circumference of the cylindrical collar to press-fit it, the cross-section of the flow path 6 is blocked or the cross-sectional area is changed due to the occurrence of burrs. It doesn't happen. Therefore, the stable flow path 6 is formed, and stable fuel injection characteristics are obtained. Further, since it is not necessary to form the flow path 6 in the needle valve 5, it is not necessary to increase the diameter of the needle valve 5, and it is possible to avoid an increase in weight and deterioration of response that would occur if the diameter of the needle valve 5 were increased.

Next, a method of manufacturing a fuel injection valve according to an embodiment of the present invention will be described. Forming the spiral groove (flow path 6) on the inner peripheral surface of the needle valve built-in portion (the cylindrical collar 1 when the cylindrical collar 1 is mounted) of the valve body 4 is performed by various methods as described above. While providing advantages, it is extremely difficult to form by machining and, if at all, would be extremely expensive. For this reason, conventionally
A spiral groove was formed around the part. However, according to the manufacturing method of the present invention, the spiral groove can be easily formed on the inner circumference of the component. In the method of the present invention, the inner diameter of the needle valve built-in portion (the cylindrical collar 1 when the cylindrical collar 1 is mounted) of the valve body 4 is formed to be larger than the outer diameter of the needle valve 5, and the space between the two is provided. The coiled collar 2 can be placed in the.

Next, as shown in FIG. 1, an elongated material 2 '(for example, a strip-shaped flat plate) is spirally wound around a cylinder (not shown), and further wound so as to form a gap 6'between the materials 2'. As a result, the coiled collar 2 is formed. Next, as shown in FIG. 2, the coiled collar 2 is attached to the inner peripheral surface of the needle valve built-in portion of the valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted) and brazed. Fix it. This can form a spiral groove. When the cylindrical collar 1 is used, the coiled collar 2 is put into a cylinder slightly longer than the coiled collar 2 and fixed, and then both end faces are processed to complete the process as shown in FIG. Then, as shown in FIG. 3, when the needle valve 5 is inserted, the spiral flow passage 6 has a coiled collar 2 and a valve body 4 (the cylindrical collar 1 when the cylindrical collar 1 is mounted). And the needle valve 5 are formed.

Next, the operation of the method for manufacturing the fuel injection valve will be described. Since the inner diameter of the needle valve built-in portion of the valve body 4 is as small as several mm, it is extremely difficult to form a spiral groove on the inner peripheral surface of this portion by cutting. Also,
If a groove is formed by electric discharge machining, it will be extremely expensive even if it can be formed. However, in the above-described manufacturing method, the coiled collar 2 may be manufactured and then inserted and brazed, so that the manufacturing is easy.
When the cylindrical collar 1 is provided and the coil-shaped collar 2 is inserted and brazed on the inner periphery of the cylindrical collar 1, the handling is easy, the approach to the brazing surface is easy, and the manufacturing is very easy.

[0014]

According to the first aspect of the present invention, since the spiral flow passage is formed on the inner peripheral surface side of the valve body, the flow passage cross-section is deformed by the pressure input, and the flow passage cross-sectional area due to the flash at the time of press-fitting is reduced. Changes can be prevented. Occasionally, since a spiral groove is formed on the valve body side, it is not necessary to increase the diameter of the needle valve for forming the groove, and responsiveness does not deteriorate due to an increase in inertia. According to the second aspect of the present invention, the spiral flow passage can be formed by simply winding the elongated material in a spiral shape and mounting and fixing it on the inner circumference of the valve body, so that the flow passage can be easily formed.

[Brief description of drawings]

FIG. 1 is a perspective view of a coiled collar forming step of a method for manufacturing a fuel injection valve according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a stage where the coiled collar of FIG. 1 is mounted on a cylindrical collar (valve body).

FIG. 3 is a cross-sectional view of a tip portion of a fuel injection valve according to an embodiment of the present invention manufactured by mounting the cylindrical collar of FIG. 2 on a valve body.

FIG. 4 is a sectional view of a tip portion of a conventional fuel injection valve in which a spiral groove is formed on the outer periphery of a cylindrical collar.

[Explanation of symbols]

 1 Cylindrical collar (part of valve body) 2 Coiled collar 3 Brazing layer 4 Valve body 5 Needle valve 6 Helical flow path

Claims (2)

[Claims] 1. A fuel injection valve having a needle valve and a valve body containing the needle valve, wherein an inner diameter of a needle valve built-in portion of the valve body is formed to be larger than an outer diameter of the needle valve. A fuel injection valve, characterized in that a spiral flow path is formed between the needle valve built-in portion of the valve body and the needle valve. 2. A method of manufacturing a fuel injection valve having a needle valve and a valve body containing the needle valve, wherein the inner diameter of the needle valve built-in portion of the valve body is made larger than the outer diameter of the needle valve. Forming a coiled collar by spirally winding an elongated material with a gap between the materials, and fixing the coiled collar to the needle valve built-in portion of the valve body, the coiled collar, the valve body and the needle. A method for manufacturing a fuel injection valve, characterized in that a spiral flow path is formed by the valve.