JPH1144275A - Solenoid valve for fuel injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solenoid valve for a fuel injection device to generate the high attraction force of an electromagnetic coil providing a magnetic path area and to cope with a demand for improvement of responsiveness at the same outline size and the increase of an operable fuel pressure. SOLUTION: Since it is noticed that a seal member 22 contracts a magnetic passage area between an electromagnetic coil 11 and an armature 5 and by enlarging the magnetic path area, a necessary suction force is generated even by the same magnetomotive force. An electromagnetic coil 11 and a seal member 22 formed of a non-magnetic substance are arranged in an annually formed opening space part 26 at one end of the armature 5 side in the axial direction of inner and outer core parts 23, 24 and 25, being a core part 21, to close an opening space part 26. Further, the outside diameter D of the seal member 22 is reduced to a value lower than the outside diameter C of an electromagnetic coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solenoid valve for a fuel injection device, and more particularly to a solenoid valve for a fuel injection device capable of setting a large suction force.

[0002]

2. Description of the Related Art When a large suction force is required for a solenoid of a solenoid valve used in a conventional fuel injector such as an electromagnetic injector for gasoline intake pipe injection or high-pressure in-cylinder direct injection, a plunger type is used. A disk-type solenoid that can set a suction area larger than that of a solenoid is generally used. That is,
At the same outer diameter, the disk-type solenoid can set a larger suction area, so that a larger suction force can be obtained. Therefore, it is relatively easily used when operation is required in a high responsiveness or high fuel pressure state. For example, Japanese Patent Application Laid-Open No. Hei 8-189439,
JP-A-8-210217 and the like. However,
Even with this disk-type solenoid, there is a problem that the suction force that can be obtained in a limited space is limited.

[0003] A conventional solenoid valve 1 for a fuel injection device will be outlined with reference to FIG. FIG. 3 is a longitudinal sectional view of the solenoid valve 1 for a fuel injection device. The solenoid valve 1 for a fuel injection device includes a core portion 2, an electromagnetic coil 3, a seal member 4, and a disk-type armature 5.
And a needle valve 6.

The core portion 2 is made of a magnetic material, and surrounds the inner and outer diameter sides of the electromagnetic coil 3 to pass a magnetic flux. It can be installed.

[0005] The electromagnetic coil 3 has a bobbin 10 to which a terminal 9 for energizing is attached, and a coil 11 for generating a magnetomotive force by energizing, and a magnetic circuit can be formed in the core portion 2.

The seal member 4 is made of a non-magnetic material, and blocks magnetic paths on the inner and outer peripheral sides of the core 2 to secure a magnetic path between the core 2 and the armature 5. In addition, a seal is provided to prevent fuel from entering the electromagnetic coil 3 from the fuel passage 7 side.

The armature 5 is made of a magnetic material and forms a magnetic circuit with the core 2 to form an electromagnetic coil 3.
(The core part 2).

[0008] The needle valve 6 is attached to the armature 5 and allows fuel to be directly injected from an injection hole 13 of a valve seat 12 into an intake pipe or a cylinder.

The solenoid valve 1 for a fuel injection device
In assembling, the electromagnetic coil 3 is inserted into the core portion 2 from the armature 5 side (the lower side in the figure), the sealing member 4 is press-fitted into the core portion 2, and then the entire circumference is welded.

In the solenoid valve 1 for a fuel injection device having such a structure, the suction force F for sucking the armature 5 when the electromagnetic coil 3 is excited is F = φ ² / (μ
· S · ν). Where φ is the amount of magnetic flux (w
b), μ is the magnetic permeability, S is the area of the suction portion (the portion where the core portion 2 faces the armature 5 and the sealing member 4 is excluded),
And ν are leakage coefficients.

That is, the attraction force F of the fuel injector solenoid valve 1 is determined by the amount of magnetic flux φ. Generally, magnetic materials have a fixed saturation magnetic flux density.
The maximum value of the magnetic flux amount φ is proportional to the magnetic path cross-sectional area. In short, the suction force F can be increased by increasing the magnetic path cross-sectional area.
Of the magnetic path cross-sectional area opposed to the armature 5 of the seal member 4
Does not contribute to the attraction of the armature 5 by the electromagnetic coil 3, the usable attraction force F and the magnetic path area are limited, and in the conventional solenoid valve 1 for a fuel injection device, the magnetic path cross-sectional area is not so large. There is a problem that it is not possible to take a large amount and it is difficult to increase the suction force F. Therefore, if the core portion 2 has the same outer diameter, the solenoid valve 1 for a fuel injection device has a problem that it cannot cope with a case where a further improvement in responsiveness and an increase in operable fuel pressure are required. .

Such a problem is an obstacle to a demand for a higher fuel injection pressure and an improvement in responsiveness. For example, it is necessary to increase the attraction force F with the same outer diameter or to use a smaller electromagnetic coil 3. It is required to generate a sufficient suction force F.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a solenoid valve for a fuel injection device capable of obtaining a larger suction force than conventional ones. I do.

Another object of the present invention is to provide a solenoid valve for a fuel injection device capable of obtaining a larger magnetic path area than conventional ones.

It is another object of the present invention to provide a solenoid valve for a fuel injection device capable of setting a large suction force without increasing the outer diameter.

Another object of the present invention is to provide a solenoid valve for a fuel injection device which can respond to requests for improved responsiveness and increased operable fuel pressure with the same outer diameter.

Further, the present invention provides a solenoid valve for a fuel injection device capable of increasing the attraction force of an electromagnetic coil in the same space as a conventional one and realizing high responsiveness and good operability under a high fuel pressure state. That is the task.

[0018]

That is, according to the present invention, the sealing member reduces the magnetic path area between the electromagnetic coil and the armature, and if the magnetic path area of this portion is enlarged, the same magnetomotive force can be obtained. The first aspect of the present invention focuses on the necessity of obtaining an attractive force, and a first invention is directed to a core portion made of a magnetic material, an electromagnetic coil capable of forming a magnetic circuit in the core portion, and a core portion. A solenoid valve for a fuel injection device, comprising: a disk-type armature capable of adsorbing to the armature; and a needle valve attached to the armature and capable of injecting fuel from an injection hole, wherein the core portion includes an inner core portion and an inner core portion. In addition to the outer core portion, one end of the inner core portion and the outer core portion on the armature side in the axial direction is opened in a ring shape to form an opening space. The electromagnetic coil is provided in the open space, and a seal member made of a non-magnetic material is further provided to close the open space, and the outer diameter of the seal member is smaller than the outer diameter of the electromagnetic coil. A solenoid valve for a fuel injection device.

According to a second aspect of the present invention, there is provided a core portion made of a magnetic material, an electromagnetic coil capable of forming a magnetic circuit in the core portion,
A disk-type armature that can be attracted to this core,
A solenoid valve attached to the armature, the needle valve being capable of injecting fuel from an injection hole, the solenoid valve for a fuel injection device, wherein the core portion comprises an inner core portion and an outer core portion; One end of the armature side in the axial direction of the core portion and the outer core portion is opened in a ring shape to form an open space portion, and the electromagnetic coil is provided in the open space portion, and the inner circumferential side of the open space portion is provided. A solenoid member for a fuel injection device, wherein the opening space is closed by providing a sealing member made of a non-magnetic material on the outer peripheral side of the opening space. is there.

[0020] The inner core portion and the outer core portion include:
The inner core portion has a hollow cylindrical shape, and the outer core portion has a hollow cylindrical shape having a step capable of forming the opening space on the inner peripheral surface thereof. can do.

An elastic tongue for improving the sealing performance can be formed on the sealing member.

Further, with regard to a division form for dividing the core portion into an inner core portion and an outer core portion, it is possible to assemble as a solenoid valve and to reduce the cross-sectional area of the non-magnetic sealing member. If possible, any configuration can be adopted.

In the solenoid valve for a fuel injection device according to the present invention, the seal member prevents fuel from entering the electromagnetic coil portion, secures a magnetic path, and reduces the cross-sectional area of the seal member. The magnetic path area between the electromagnetic coil and the armature can be increased by that much, and the attraction of the armature by the electromagnetic coil can be increased.

Therefore, the attraction force of the electromagnetic coil can be increased with the same outer diameter as the solenoid valve for the fuel injection device, and the current or the number of turns of the coil to energize the electromagnetic coil in order to obtain a necessary and sufficient attraction force. , The boost value and the rising speed can be increased, and the size of the electromagnetic coil itself can be reduced. That is, the magnetic flux density can be reduced in order to generate the same attractive force by increasing the magnetic path area, and the electromagnetic coil can be reduced accordingly.

For example, in the first invention, since the outer diameter of the sealing member is smaller than the outer diameter of the electromagnetic coil, a large amount of magnetic flux can be generated between the electromagnetic coil and the armature, and the attraction force of the armature by the electromagnetic coil. Can be increased.

Further, in the second aspect, since the core portion is disposed on the outer peripheral side of the seal member, the magnetic flux also passes through the core portion, so that the armature can be sucked with a larger suction force.

Further, the thickness of the sealing member is set small,
If the inner and outer magnetic path cross-sectional areas are arranged in a well-balanced manner, the area of the suction portion becomes the square of the diameter, so that the magnetic path cross-sectional area can be more effectively increased. However, the leakage of the magnetic flux that does not act on the suction also increases, so that there is an optimum value for the thickness of the seal member.

[0028]

FIG. 1 shows a solenoid valve 20 for a fuel injection device according to a first embodiment of the present invention. However, the same parts as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted. FIG. 1 is a longitudinal sectional view of a solenoid valve 20 for a fuel injection device,
The fuel injector solenoid valve 20 has a core 21 corresponding to the core 2 and a seal member 22 corresponding to the seal member 4 together with the electromagnetic coil 3, the armature 5 and the needle valve 6. The core portion 21 has an inner core portion 23, a first outer core portion 24, and a second outer core portion 25 each having a hollow cylindrical shape. The inner core part 23, the first outer core part 24, and the second outer core part 25 are separate bodies, but are made of a magnetic material, and pass a magnetic flux.

The seal member 22 is made of a non-magnetic material, and supports the bobbin 10 of the electromagnetic coil 3 together with the second outer core 25.

That is, the first outer core portion 24 is
4A, the inner core portion 23 and the first outer core portion 2
4, an open space 26 is formed in a ring shape at one end facing the armature 5 opposite to the step 24A, and the open space 26 is provided with the electromagnetic coil 3, the seal member 22 and the second The outer core portion 25 is provided. In other words, a cylindrical seal having an outer diameter D larger than the inner core portion 23 is provided on the end face of the core portion 21 (the inner core portion 23, the first outer core portion 24, and the second outer core portion 25) on the armature 5 side. A member 22 is provided, and a second outer core portion 25 made of a ferromagnetic material is located outside the member 22. However, the outer diameter D of the seal member 22 is equal to the outer diameter C of the electromagnetic coil 3.
It is smaller. These three members are integrally manufactured by projection welding, press fitting welding, or the like.

As shown in an enlarged manner, the lower end surface 22A of the seal member 22 on the armature 5 side is slightly smaller than the lower end surface 23A of the inner core portion 23 and the lower end surface 25A of the second outer core portion 25. The armature 5 is protruded toward the armature 5 side to provide a slight gap portion 27, and when the armature 5 is sucked and lifted upward in the drawing, the armature 5 abuts only on the lower end surface 22A of the non-magnetic sealing member 22, The armature 5 can be easily moved downward in the drawing by the urging force of the return spring 8 when the electromagnetic coil 3 is demagnetized.

Also, a solenoid valve 2 for a fuel injection device is provided.
In assembling the assembly 0, the sealing member 22, the inner core portion 23, and the second outer core portion 25 are integrated, and the electromagnetic coil 3 is inserted into the inner core portion 23 from above in the drawing. Further, the first outer core portion 24 is inserted from above,
After press-fitting into the inner core portion 23, the entire circumference is welded and fixed.

In the solenoid valve 20 for a fuel injection device having such a configuration, as the thickness W of the seal member 22 becomes smaller, the magnetic path and the suction portion (the second outer core portion 25 and the second outer core portion 25) have the same outer diameter. Since the cross-sectional area of the inner core portion 23) can be set large, the suction force can be increased.

The magnetic path resistance R of the gap 27 is R = 1 /
(Μ · S). If the cross-sectional area S of the attracting portion is large, the magnetic path resistance R is small, and the magnetic flux density of the core portion 21 is reduced. Therefore, the magnetomotive force for obtaining the same attractive force F may be reduced. In other words, an increase in the attraction force F means a decrease in the boosted value, and it is possible to reduce the value of the current flowing through the coil 11 of the electromagnetic coil 3 or the number of turns thereof.

FIG. 2 is a longitudinal sectional view showing an example in which the solenoid valve for a fuel injection device according to the second embodiment of the present invention is incorporated in an actual fuel injection device 30. Solenoid valve 31 for fuel injection device
Together with the connector 32 and the upper valve housing 3
3 (corresponding to the first outer core portion 24), a lower valve housing 34, a fuel supply pipe 35, a spring seat 36, and the valve seat 12.

The fuel injector solenoid valve 31 is
Core 21 (inner core 23, first outer core 24,
A seal member 37 corresponding to the seal member 4 is provided together with the second outer core portion 25), the electromagnetic coil 3, the disk-type armature 5, and the needle valve 6. As shown in an enlarged manner, the sealing member 37 is provided between the first elastic tongue piece 38 and the bobbin 10 of the electromagnetic coil 3 at a radially pressed portion between the sealing member 37 and the second outer core portion 25. A second elastic tongue piece 39 is formed in the axial pressure contact portion between
The fuel sealing performance has been improved.

In the fuel injection device 30 equipped with the fuel injection device solenoid valve 31 having such a configuration, the fuel is sealed by the seal member 37 as in the fuel injection device solenoid valve 20 described with reference to FIG. At the same time, since the radial cross-sectional area of the seal member 37 is reduced, the magnetic path area formed between the electromagnetic coil 3 and the armature 5 can be increased accordingly, and the attraction force of the electromagnetic coil 3 can be increased. it can.

[0038]

As described above, according to the present invention, since the size of the seal member is reduced, the attraction force of the electromagnetic coil can be increased in the same space. Further, since the magnetic path cross-sectional area increases, the magnetomotive force at the same attractive force can be reduced. Further, with the improvement of the responsiveness of the fuel injection device and the increase of the used fuel pressure, the set force of the return spring can be increased, so that the adjustment range of the injection amount can be increased, and the performance thereof is improved. It becomes possible. Further, if the fuel pressure can be set high, atomization of the spray can be promoted, and the combustion and exhaust characteristics of the engine can be improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a solenoid valve 20 for a fuel injection device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing an example in which a solenoid valve for a fuel injection device 31 according to a second embodiment of the present invention is incorporated in an actual fuel injection device 30.

FIG. 3 is a longitudinal sectional view of a conventional solenoid valve 1 for a fuel injection device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Solenoid valve for fuel injection devices (FIG. 3) 2 Core part 3 Electromagnetic coil 4 Non-magnetic sealing member 5 Disk type armature 6 Needle valve 7 Fuel passage 8 Return spring 9 Terminal for electricity supply 10 Bobbin of electromagnetic coil 3 11 Coil of electromagnetic coil 3 12 Valve seat 13 Injection hole 20 Solenoid valve for fuel injection device (first embodiment, FIG. 1) 21 Core portion (inner core portion 23, first outer core portion 2)
4. Second outer core portion 25) 22 Non-magnetic seal member 22A Lower end surface of seal member 22 Inner core portion 23A Lower end surface of inner core portion 24 First outer core portion 24A First outer core portion 24 step portion 25 second outer core portion 25A lower end surface of second outer core portion 25 ring-shaped opening space portion 27 lower end surface 23A of inner core portion 23 and lower end surface 25A of second outer core portion 25 A small gap between the armature 5 and the armature 30 30 Fuel injector (FIG. 2) 31 Solenoid valve for fuel injector (second embodiment, FIG. 2) 32 Connector 33 Upper valve housing (First outer core portion) 24) 34 Lower valve housing 35 Fuel supply pipe 36 Spring seat 37 Non-magnetic seal member 38 First elastic tongue of seal member 37 39 Seal member 37 second elastic tongue D outer diameter of seal member 22 (D <C) C outer diameter of electromagnetic coil 3 W thickness of seal member 22

Claims (3)

[Claims] 1. A core section made of a magnetic material, an electromagnetic coil capable of forming a magnetic circuit in the core section, a disk-type armature that can be attracted to the core section, A solenoid valve for a fuel injection device, comprising: a needle valve capable of injecting fuel, wherein the core portion comprises an inner core portion and an outer core portion, and an axial direction of the inner core portion and the outer core portion. At
One end of the armature side is opened in a ring shape to form an opening space, the electromagnetic coil is provided in the opening space, and a sealing member made of a non-magnetic material is further provided to close the opening space, An outer diameter of the seal member is smaller than an outer diameter of the electromagnetic coil. 2. A core portion made of a magnetic material, an electromagnetic coil capable of forming a magnetic circuit in the core portion, a disk-type armature adsorbable to the core portion, A solenoid valve for a fuel injection device, comprising: a needle valve capable of injecting fuel, wherein the core portion comprises an inner core portion and an outer core portion, and an axial direction of the inner core portion and the outer core portion. At
An open space is formed by opening one end of the armature side in a ring shape, the electromagnetic coil is provided in the open space, and a seal member made of a non-magnetic material is provided on the inner peripheral side of the open space. The solenoid valve for a fuel injection device, wherein the opening space is closed by further positioning the outer core portion on the outer peripheral side of the opening space. 3. The inner core portion and the outer core portion are formed of different members from each other, the inner core portion has a hollow cylindrical shape, and the outer core portion has an inner peripheral surface thereof. 3. A solenoid valve for a fuel injection device according to claim 1, wherein said solenoid valve has a hollow cylindrical shape having a step capable of forming said opening space.