JPH08285115A - Solenoid valve - Google Patents

Abstract

PURPOSE: To efficiently apply a magnetic flux to an armature by reducing the magnetic flux leaked from a stator so as to generate a large attraction force and further to miniaturize a solenoid valve. CONSTITUTION: A spacer 8 provided for setting the lifting amount of a valve element 5 is formed of a well-conductive material, a part other than a portion opposite to the stator 10 of an armature 5a is surrounded, and the well- conductive material is penetrated by a magnetic flux, thereby generating a relatively large eddy current, and by this generated eddy current, further leakage of a magnetic flux is effectively shut off. Also, almost no magnetic fluxes are leaked from the stator 10 to the outside, resulting in efficient application of a magnetic flux to the armature 5a, and a large attraction force is generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solenoid valve, and more particularly to a solenoid valve for controlling a fuel injection nozzle used in a fuel injection device for an internal combustion engine.

[0002]

2. Description of the Related Art As a structure of a conventional solenoid valve, JP-A-3-
125086. FIG.
Shows an example of the electromagnetic three-way valve. In FIG. 3, the tubular valve body 5P is brought into close contact with the wall surface of the equipment EP in which the flow paths E1P and E2P are formed, and the tubular outer valve 41P is vertically movably inserted in the center through hole. . Inside the cylinder of the outer valve 41P, an inner valve 43P composed of a pair of upper and lower rods that are in contact with each other is arranged.
The outer valve 41P pushed to the lower position by the coil spring 44P connects the flow paths 51P and 52P via the valve internal flow path 411P. By energizing the electromagnetic coil 3P, the outer valve 41P rises until its inner peripheral step portion abuts on the tip of the inner valve 43P, so that the flow paths 51P and 53P communicate with each other.

A thick disk-shaped armature 42P is fixed to the outer periphery of the upper end of the outer valve 41P. The armature 42P is formed by a non-magnetic cylindrical spacer 2P arranged on the outer periphery of the top surface of the valve body 5P. It is located in the space formed. A cylindrical container-shaped valve housing 6P that opens downward is provided on the spacer 2P, and the stator 1P is housed in the housing 6P.

[0004]

The conventional solenoid valve as shown in FIG. 3 has no problem in a large engine such as a truck, but in recent years, it is desired to mount a fuel injection nozzle using the solenoid valve in a small engine. With the increasing demand for, the miniaturization of solenoid valves has become necessary. In the conventional configuration, the magnetic flux from the stator becomes so-called leakage magnetic flux that leaks not only to the armature but also to the outside. Therefore, in order to generate an attractive force for operating the valve, it is necessary to add extra energy up to the amount consumed as the leakage magnetic flux. Therefore, it is difficult to obtain a large suction force with a small physique, and it is difficult to significantly reduce the size of the solenoid valve.

An object of the present invention is to reduce the leakage magnetic flux from the stator so that the magnetic flux can efficiently act on the armature to generate a large attraction force, and further, the solenoid valve can be downsized.

[0006]

In order to achieve the above object, the present invention provides an armature integral with a valve body so as to face a lower surface of a stator around which an electromagnetic coil is wound, as shown in claim 1. In the electromagnetic valve described above, the technical means is adopted in which the spacer provided for setting the lift amount of the valve body is formed of a material having good conductivity, and is configured so as to surround a portion of the armature other than the portion facing the stator. It is a thing.

[0007]

[Function] The spacer provided for setting the lift amount of the valve body is formed of a material having good conductivity, and is constituted so as to surround the portion of the armature other than the portion facing the stator, so that the magnetic flux in the material having good conductivity is increased. A relatively large eddy current is generated by the penetration of the magnetic field, and the generated eddy current can effectively shield further leakage of magnetic flux. Further, the magnetic flux from the stator hardly leaks to the outside, and it works efficiently on the armature, so that a large attractive force can be generated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an example in which the present invention is applied to a three-way valve, and a high pressure port 2, a control port 3 and a drain port 4 are arranged in a body 1. An outer valve 5, which is a valve body having an armature 5a above it, is slidably accommodated in the body 1 and seated by being biased downward by a valve spring 6. An inner valve 7 is slidably accommodated in the outer valve 5 and is pushed upward by high pressure fuel introduced from a high pressure source (not shown) through the high pressure port 2. A spacer 8 is arranged on the upper portion of the body 1, and a stator 10 and a solenoid 9 are arranged thereon.

The spacer 8 sets the lift amount of the outer valve 5 forming the valve body by changing the axial dimension of the cylindrical portion 8a of the spacer 8. To explain the operation, the control port 3 is connected to a back pressure chamber of a known fuel injection nozzle (not shown), and when the solenoid 9 is energized, the stator 10 is connected.
The outer valve 5 rises by the suction force generated between the armature 5a and the armature 5a, and the inner valve 7 is seated. Then, the communication between the high pressure port 2 and the control port 3 is cut off, and the control port 3 communicates with the drain port 4. Therefore, the pressure in the back pressure chamber connected to the control port 3 decreases, and the fuel injection nozzle (not shown) opens.

At this time, the electromagnetic force generated in the solenoid 9 also acts on the spacer 8. This spacer 8 is conventionally SU
A material having relatively poor conductivity such as S304 was used. However, by using a material having relatively good conductivity such as aluminum or copper, the magnetic flux penetrates through the material, and A large eddy current is generated, and the generated eddy current can effectively shield further leakage of magnetic flux.

Therefore, by surrounding the armature 5a with a material having a relatively high conductivity as in the structure of the present invention, it is possible to reduce the leakage magnetic flux and efficiently apply the attractive force to the armature 5a. Next, FIG. 2 shows a second embodiment in which the present invention is applied to a two-way valve. In FIG. 2, the body 1
1, a control port 13 and a drain port 14 are arranged. The armature 15a is provided on the upper portion of the body 11.
A valve 15 that forms a valve body having
The valve spring 17 is urged downward and seated. At this time, the control port 13 and the drain port 14 are cut off. A spacer 1 made of a material having relatively high conductivity such as aluminum or copper is provided on the upper portion of the body 11.
8 is arranged on the stator 20 and the solenoid 1
9 are arranged.

The spacer 18 sets the lift amount of the valve 15 forming the valve body by changing the axial dimension of the cylindrical portion 18a of the spacer 18. For operation, solenoid 1
By energizing 9, a suction force is generated between the stator 20 and the armature 15a, and the valve 15 is lifted to separate from it, so that the control port 13 and the drain port 14 communicate with each other.

At this time, the electromagnetic force generated in the solenoid 19 penetrates through the spacer 18 made of a material having a relatively high conductivity to generate a large eddy current as in the first embodiment. Due to the eddy current, further leakage of magnetic flux can be effectively shielded. Therefore, the same effect as that of the first embodiment can be obtained, and the suction force can efficiently act on the armature 15a.

[0014]

The magnetic flux from the stator hardly leaks to the outside due to the generation of a relatively large eddy current.
It works efficiently on the armature and can generate a large suction force. For this reason, the loss that has been conventionally lost as a leakage magnetic flux acts as an effective attractive force, so that the solenoid valve can be downsized accordingly.

[Brief description of drawings]

FIG. 1 is a sectional view taken along a central axis of a solenoid valve according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the central axis of a solenoid valve according to a second embodiment of the present invention.

FIG. 3 is a sectional view taken along the central axis of a conventional solenoid valve.

[Explanation of symbols]

 5,15 Valve body 5a, 15a Armature 8,18 Spacer 10,20 Stator

Claims (1)

[Claims] 1. In a solenoid valve in which an armature integral with a valve body is arranged so as to face a lower surface of a stator around which an electromagnetic coil is wound, a spacer provided for setting a lift amount of the valve body is made of a material having good conductivity. And an electromagnetic valve which is configured so as to surround a portion of the armature other than the portion facing the stator.