JPS62191661A - Electromagnetic fuel injection device - Google Patents

Abstract

PURPOSE:To prevent deterioration in magnetic performance by means of the connection between a needle valve and a movable core by inserting an engaging part provided on the shaft body of said needle valve into two bores of said movable core, making the part on an iron core side from said engaging part of said movable core subjected to plastic deformation, and bringing said engaging part into pressure contact with the connecting wall faces between said holes. CONSTITUTION:A needle valve 3 which is moved in an integrated form with a movable core 20 to open and close an injection port, is formed with a shaft body 22 inserted into the movable core 20 and an engaging part 23 formed with a projection on the outer periphery of a part of the shaft body 22. A first bore 24 which is opened on an end part on the other side of the end part opposite to an iron core, and in which the engaging part 23 is axially inserted, while a second bore 25 which is connected to the first bore 24, and in which the engaging part 23 can be rotated in the movable core 20, are formed in the movable core 20. The engaging part 23 in the second bore 25 is engaged with connecting wall faces 27a, 27b between both bores 25 and 24, and the part of the movable core 20 on the iron core side from the engaging part 23 is subjected to plastic deformation, to be brought into pressure contact with the connecting wall faces 27a, 27b and fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic fuel injection device used particularly as a fuel supply device for an internal combustion engine.

[Conventional technology]

In the conventional electromagnetic fuel injection device, the
As seen in Publication No. 1071, an uneven part consisting of an annular groove and a raised part is provided on the outer periphery of the needle valve, and the core hole of the movable core and the uneven part are crimped. This is done by strongly squeezing the side wall of the movable core, and since the side wall of the movable core is a magnetic path for the electromagnetic coil, the magnetic properties change when the movable core and the needle valve are coupled, resulting in good magnetic properties. This causes problems such as variations in the magnetic characteristics of each fuel injection device, and uneven responsiveness of needle valve operation.

The present invention has been made in view of the above problems, and the movable core can maintain sufficiently good magnetic properties without deteriorating the magnetic properties before coupling with the needle valve, thereby achieving uniform and excellent magnetic properties. Spout! 1. An object of the present invention is to provide an electromagnetic fuel injection device that can obtain arsenic characteristics and high-speed response.

[Means for solving problems]

In order to solve the above problems, in the electromagnetic fuel injection device according to the present invention, the needle valve, which opens and closes the injection hole by moving together with the movable core, has a shaft inserted into the inside of the movable core. The movable core has a locking portion raised on a part of the outer periphery of the shaft body, and the movable core has a locking portion at an end opposite to the end facing the iron core of the movable core. a first hole that is open and allows the locking portion to pass through in the axial direction; and a first hole that is connected to the first hole;
a second hole that allows the locking portion to rotate relatively within the movable core after passing through the first hole; The movable core is fixed to the connecting wall surface with the first hole, and is fixedly pressed against the connecting wall surface by plastically deforming a part of the movable core on the side of the iron core from the locking portion.

[Effect]

With the above configuration, in the electromagnetic fuel injection device according to the present invention, in coupling the needle valve and the movable core, the locking portion provided in a raised manner on the shaft body of the needle valve is It is penetrated by the first hole and rotated relative to the movable core after reaching the hole described in 1 and 2, and a part of the movable core on the side of the iron core from this locking part is plastically deformed. The locking portion is press-fixed to a connecting wall surface of the second hole with the first hole. Therefore, the needle valve and the movable core are connected without strongly pressing the outer circumferential side surface, which is the main magnetic path of the movable core, so that the magnetic properties of the movable core are not deteriorated.

〔Example〕

An embodiment of the present invention will be described based on FIG. 1, FIG. 2 (al, FIG. 2 fb), FIG. 3 (a), FIG. 3 (bl, FIG. 4, and FIG. 5).

In FIG. 1, 1 is a housing, and its lower end 1
The nozzle body 2 is held by tightening a.

A needle valve 3 is housed in the nozzle body 2 so as to be movable in the axial direction. When the needle valve 3 is seated on the valve seat 4 of the nozzle body 2, the fuel injection hole 5 is closed. When it leaves the seat 4, the fuel injection hole 5 opens.

A tubular fixed core 6 is provided in the center of the housing 1, and the fixed core 6 is fixed to the housing 1 by squeezing the upper end 1b of the housing 1.

An electromagnetic coil 8 wound around a spool 7 is housed in an annular space formed between the housing 1 and the fixed iron core 6. The spool 7 is fitted into the housing 1 and the fixed core 6 via O-rings 9 and 10 in a fluid-tight manner. The electromagnetic coil 8 is connected to a terminal 12 attached to a synthetic resin connector 11 integrated with the housing 1. This terminal 12 is connected to an electronic control device 13 such as a computer, and this electronic control device 1
It receives the electric pulse 13a from 3 and transmits the electric pulse 13a to the electromagnetic coil 8.

The upper end of the fixed iron core 6 is a connector pipe 14 that is connected to a fuel supply pipe (not shown).
is supplied with fuel adjusted to a predetermined pressure. The fuel passes through a filter 15 and flows through a fuel passage 17 provided in the center of the fixed iron core 6. An adjustment pipe 18 is accommodated in the central space of the fixed iron core 6.
The fuel passage 17 is substantially connected to this adjustment pipe 18.
It is the internal space of

The azimuth 1-pipe 18 is fixed to the fixed iron core 6 by tightening the upper part 6a of the fixed iron core 6.

The upper end of a spring 19 is in contact with the lower end of this adjustment pipe 18. The lower end of the spring 19 is in contact with the movable core 20. This movable core 20 is the housing 1
The needle valve 3 is fitted and fixed inside the movable core 20 on the nozzle body 2 side, and the fixed iron core 6 side is housed integrally with the needle valve 3 so as to be movable in the axial direction. A spring 19 is inserted.

Note that the cent load of the spring 19 is set by adjusting the position where the adjust pipe 18 is fixed to the fixed iron core 6.

The connection between the needle valve 3 and the movable core 20 will be described below, but first the structure of the needle valve 3 will be further explained using FIG. 2 (al) and FIG. 2 (bl).

In FIG. 2 (al), a flange 21A is provided approximately at the center of the needle valve 3, and above this flange 21A,
A cylindrical shaft body 22 is formed to be inserted into the movable core 20, and the outer circumferential portion of the outermost part ◇:11 is raised in a stepped manner to form a stopper for fixing the needle valve 3 within the movable core 20. A stop portion 23 is formed.

Furthermore, as shown in FIG. 2(b), which is a view of the needle valve 3 in the direction of arrow (1), the cross-sectional shape of the locking portion 23 is in a circle with a larger diameter than the cross-section of the shaft body 22. A figure consisting of a set of arcs symmetrical about the center and a set of parallel chords connecting their ends.

That is, on the outer periphery of the locking portion 23, a -4, fl plane and a - set of arcuate surfaces are formed parallel to each other and facing each other.

Further, below the flange 2LA of the needle valve 3, there are two guide portions 21B, 2/2, which are in sliding contact with the inside of the nozzle body 2.
Ic is formed.

Next, the structure of the movable core 20 will be explained using FIGS. 3(a) and 3(b).

In FIG. 3 (al), three holes are formed on the axis of the movable core 20 so as to extend through the movable core 20 from the lower end 20a to the upper end 20b in a stepped manner.

The first hole 24 opening at the lower end 20a of the movable core 20 is
It extends to the center of the movable core 20 and has the same cross section as the locking part 23 so that the locking part 23 can pass through it.

Furthermore, the second hole 25 connected to this first hole 24 is
``Since this is a space in which the locking part 23 is rotated around the axis after passing through the first hole 24, its wall surface has the same shape as the circumferential surface when the locking part 23 rotates around the axis. Further, the length of the second hole 25 is set to be slightly longer than the width (i.e., length) of the locking portion 23 in the axial direction.

Furthermore, a third hole 26 is connected above the second hole 25. This third hole 26 has a circular opening larger than the cross-sectional circle of the second hole 25 and is located at the upper end 20 of the movable core 20.
It has a tapered shape in which the cross-sectional circle increases linearly until it penetrates b.

Furthermore, as shown in FIG.
5 has two connecting wall surfaces 27 with the holes 24 of the previous writing 1.
a and 27b are formed, and a doughnut-shaped cross section 28, which is a constricted portion of the movable core 20, is formed at the connection portion of the third hole 26 with the second hole.

Next, the needle valve 3 and movable core 20 configured as described above will be described.
We will explain the combination of .

The locking portion 23 formed on the needle valve 3 is inserted through the first hole 24 formed on the movable core 20 . The entire locking portion 23 reaches the second hole 25. At this time, the shaft body 22 inserted into the first hole 24 and the first
A gap is formed between the hole 24 and the wall surface of the hole 24. Next, the movable core 20 is rotated 90 degrees around the axis. Then, the connecting wall surfaces 27a and 27b in the movable core 20 are in a state opposite to the locking portion 23, so that the locking portion 23 is connected to the first hole 2.
Even if it is moved in four directions, the connecting wall surfaces 27a, 27
By being locked by contacting b, the needle valve 3 and the movable core 20 become an engaged body whose axes coincide.

Further, at this time, a portion of the opening surface of the first hole 24 on the second hole 25 side that is not covered by the locking portion 23 communicates with the second hole 25 . Therefore, a gap consistently exists between the movable core 20 and the needle valve 3.

FIG. 4 shows a state in which both of the above-mentioned engaging bodies are placed in a wringer.

In FIG. 4, the throttle device has a support cylinder 30 and a throttle rod 31, and the lower end 20a of the movable core 20 is supported by the upper opening edge 30a of the support cylinder 30, so that a part of the needle valve 3 is supported. It is stored in an internal storage section 32 of the tube 30. The axis of the housing portion 32 of the support tube 30 coincides with the axis of the engaging body of the needle valve 3 and the movable core 20, and after the needle valve 3 and the housing portion 32 are housed, the axes are aligned. In order to avoid damage, the shape of the storage portion 32 is made into a bolt-like shape consisting of a large diameter portion 32a having the same diameter as the flange 21A of the needle valve 3, and a small diameter portion 32b having the same diameter as the guide portions 21B and 21C. The flange 21A is housed in the large diameter part 32a, and the guy 1 parts 21B and 21C are housed in the small diameter part 32b.

Further, a tightening rod 31 is inserted into the third hole 26 of the movable core 20 from the direction of the upper end 20b. The squeeze rod 31 has a concave spherical lower end, and its circumferential lower end faces the donut-shaped cross section 28 . As mentioned above, the length of the second hole 25 connected to the lower part of the third hole 26 is set to be slightly longer than the length of the locking part 23, so that the locking part 23 is connected to the connecting wall surfaces 27a and 27b. In this locked state, the cross section 28 is at a higher position than the upper surface of the locking part 23.

Next, the process of fixing the needle valve 3 and movable core 20 set in the above state by operating a wringer will be described.

When the constriction rod 31 is strongly pressed downward, the constriction portion 3
The lower circumferential edge of the movable core 20 presses against the cross section 28 of the movable core 20 . Then, since the cross section 28 is located at a higher position than the upper surface of the locking portion 23, the core member inside the movable core 20 near the cross section 28 is plastically deformed and pushed inward due to this pressing force, and the locking portion 23 A part of the top surface of the is covered while being pressurized.

FIG. 5 shows a state in which the movable core 20 and the needle valve 3 are tightened and fixed in this manner.

In FIG. 5, reference numeral 20C denotes the constriction part in the movable core 20, and the needle valve 3 is connected to the movable core 20 by pressing the locking part 23 in the second hole 25 in the axial direction.
Inclusion has been fixed. Further, the constriction portion 20C is a contact portion of the spring 19.

Further, as described above, a gap is formed between the inner wall of the movable core 20 and the shaft body 22 and the locking part 23 of the needle valve 3, but this gap has a role as a fuel passage,
It communicates with the third hole 26.

Now, referring again to FIG. 1, the guide portions 21B and 21C formed in the needle valve 3 slide against the inner wall portion of the nozzle body 2 through a gap. In addition, both guide parts 21B,
A fuel passage 33 is secured in 21C. A spacer 34 having a through hole 34a in the center is sandwiched between the housing 1 and the nozzle body 2, and the shaft body 22 of the needle valve 3 is passed through the gap in the through hole 34a. There is. Further, when the needle valve is lifted upward in the axial direction, the upper part of the flange 21A comes into contact with the lower part of the spacer 34, and the amount of lift is regulated.

The above is the configuration of this embodiment. In the electromagnetic fuel injection device having the configuration described above, the fuel pressurized to a constant pressure passes through the connector pipe 14, passes through the filter 15, and enters the fuel passage in the adjust pipe 18. 17, spring 1
9, from the third hole 26 of the movable core 20, through the second hole 25 into which the locking part 23 of the needle valve 3 is fitted, and through the first hole 24 through which the shaft body 22 is penetrated. It reaches around the spacer 34. The fuel then passes through the through hole 34a of the spacer 34, and further reaches the valve seat 4 through the fuel passage 33, which is a gap between the guide portions 21B and 21C and the inner wall of the nozzle body 2.

Then, an electric pulse is transmitted from the electronic control device 13 to the electromagnetic coil 8.
If the fixed core 6 is not magnetized, the movable core 20 is pushed down by the pressing force of the spring 19, and the needle valve 3 is in close contact with the valve seat 4, closing the fuel injection valve 5. . Therefore, no fuel is injected.

When an electric pulse 13a is applied from the electronic device 13 to the electromagnetic coil 8, the fixed core 6 is magnetized, and the movable core 20 is attracted to the fixed core 6 against the biasing force of the spring 19. For this reason, the needle valve 3 connected to the movable core 20 is lifted and is therefore separated from the valve seat 4, so that the fuel injection hole 5 is opened and the fuel that has reached just before the fuel injection hole 5 is injected.

When the application of the electric pulse to the electromagnetic coil 8 is finished,
Since the magnetization of the fixed iron core 6 disappears, the attractive force of the fixed iron core 6 to the movable core 20 disappears, and the movable core 20 is moved downward under the pressing force of the spring 19, so that the needle valve 3 is moved to the valve seat 4. Since the driver is seated, the fuel injection hole 5 is closed, and the fuel injection ends.

The electromagnetic fuel injection device according to the embodiment described above provides the following effects.

Adjacent 1 to the movable core 20 - Fuel passage 1 in the pipe 18
The fuel sent from 7 smoothly flows into the hole of the movable core 20 directly below the adjustment pipe 18 and reaches the connecting portion between the movable core 20 and the needle valve 3. There, the first to third holes 24 to 26 for connecting the movable core 20 and the needle valve 3 are secured as fuel passages without any special processing for fuel distribution. You can use it to guide you downwards.

Further, the third hole 26 connected to the upper part of the second hole 25 is
It also plays the role of receiving the spring 19, so
The lower part of the spring 19 is housed in the hole.

Therefore, even if the valve is repeatedly operated, the spring 19 will not deviate from the axial direction. In other words, the spring 19 can always reliably press the crest 20C in the movable core 20 downward in the axial direction, thereby improving the response of the valve. There is no variation in gender.

In addition, since the locking portion 23 of the needle valve 3 is compressed so as to be in pressure contact with the connection wall surfaces 27a and 27b in the movable core 20, it is only necessary to maintain high dimensional accuracy of both of these pressure contact surfaces, and the remaining is the axial strangling force in the third hole 2
6, the movable core 20 and the needle valve 3 are fixed without shifting their axes.

Also, the constricted portion 2 in which the movable core 20 is plastically deformed due to constriction.
Since 0C is not a part forming the main magnetic path of the movable core 20, the magnetic properties of the movable core 20 do not change due to the coupling between the movable core 20 and the needle valve 3, and good magnetic properties can be maintained. Regarding operation, good responsiveness can be expected.

In addition, the needle valve 3 is inserted into the movable core 20, and the locking part 2
3 reaches the second hole 25 and then rotates the movable core 20 by 90 degrees.
When rotated, the needle valve 3 is connected to the connecting wall surface 27a.

27b, and because the outer circumferential wall of the locking portion 23 and the circumferential wall of the second hole 25 are in contact with each other at that time, the movable core 20 and the needle valve 3 can be coaxially connected with each other with an extremely easy operation before the tightening operation. It is set in the wringer while still being engaged.

Further, unlike the conventional configuration, there is no plastic deformation due to pressure applied to the outer peripheral wall portion of the movable core 20, so the outer shape of the movable core 20 does not change even after the needle valve 3 is connected.
Can be managed uniformly.

Furthermore, the fuel passage secured within the movable core 20 will not be unevenly deformed for the same reason.

Although the above is one embodiment of the present invention, other electromagnetic fuel injection devices may be configured as follows.

Of the holes formed in the movable core 20, the third hole 26 is eliminated and only the second hole 25 is left, and the needle valve 3 is fixed by constricting a part of the end surface 20b of the movable core 20 facing the iron core. You may do so.

Connection wall surfaces 27a, 27 of the second hole 25 in the movable core 20
b is engaged with the locking portion 23 of the needle valve 3, but the locking portion 23 of the movable core 20 after rotation is engaged with the connecting wall surfaces 27a and 27b.
A recessed portion may be formed for fitting.

Furthermore, the shape of the locking portion 23 is not limited to that according to the above-mentioned embodiment; for example, the cross section thereof may be elliptical or substantially quadrangular.

Moreover, although the first to third holes formed in the movable core 20 are used as fuel passages as they are, holes for fuel passages may be separately provided in the movable core 20.

Further, the locking portion 23 does not need to be provided at the extreme end of the needle valve 3, and may be provided near the center of the shaft body 22.

〔Effect of the invention〕

As described above, in the electromagnetic fuel injection device according to the present invention, the portion that plastically deforms the movable core is mainly Cs.
Since the movable core is not an air passage, the magnetic properties of the movable core after the movable core and the needle valve are connected will not deteriorate compared to the magnetic properties before connection. Therefore, by being able to maintain sufficiently good magnetic properties, it becomes possible to obtain uniform and sharp ejected star properties and responsiveness.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an electromagnetic fuel injection device according to an embodiment of the present invention, FIG. 2 is a front view of the needle valve of the electromagnetic fuel injection device shown in FIG. , Figure 2 (
81 A view from the arrow ■ direction of the needle valve shown in Figure 3 (
a) is a cross-sectional view of the movable core of the electromagnetic fuel injection device shown in FIG. 1, FIG. 3 fb) is a view of the movable core shown in FIG. The needle valve shown in FIGS. 2 (a) and 2 (b) is engaged with the movable core shown in FIGS. Fig. 5 is a sectional view showing a state in which the needle valve shown in Fig. 4 and the movable core are fixed. 3... Needle valve, 5... Injection hole, 6...・・Iron core,
20... Movable core, 22... Shaft body, 23... Locking portion, 24... First hole. 25...Second hole, 27a, 27b...Connection wall surface.

Claims (4)

[Claims] (1) An iron core that is magnetized by energization of an electromagnetic coil, a movable core that is disposed opposite to one end of the iron core with a gap therebetween, and that moves toward the iron core when the electromagnetic coil is energized; In an electromagnetic fuel injection device having a needle valve that opens and closes an injection hole by moving together with the movable core, the needle valve includes a shaft body fitted inside the movable core; The movable core has a locking part raised on a part of the outer periphery of the shaft body, and the movable core has an opening at an end opposite to the end facing the iron core of the movable core. , a first hole through which the locking part can pass in the axial direction; and a first hole connected to the first hole, the locking part rotating relatively within the movable core after passing through the first hole. A second hole is formed in the movable core, and the locking part is locked to a connecting wall surface with the first hole in the second hole after the rotation, and the locking part is locked to a connecting wall surface with the first hole in the second hole, and An electromagnetic fuel injection device, characterized in that the electromagnetic fuel injection device is fixed to the connection wall surface by plastic deformation of a portion closer to the iron core than the stop portion. (2) The electromagnetic fuel injection device according to claim 1, wherein the locking portion has a cross-sectional shape other than a circle. (3) A third hole having a larger cross section than the second hole is connected to the second hole on the axis in the movable core, and is connected to the end of the movable core facing the iron core. Claim 1, wherein the locking portion is press-fixed into the second hole by compressing a connecting wall surface with the second hole inside the third hole. 1st term or 2nd term
The electromagnetic fuel injection device described in . (4) The electromagnetic fuel injection device according to claim 1, 2, or 3, wherein a cross section of the first hole has substantially the same shape as a cross section of the locking portion.