JPH0370864A - Electromagnetic fuel injection device - Google Patents

Abstract

PURPOSE:To certainly ensure oil sealing property by providing a housing made of a metal on the outer circumferential part of an electromagnetic coil, and directly connecting said housing with a fixed iron core by a sealing member. CONSTITUTION:When an electric current is supplied to a terminal 34 from an electronic control circuit, and an exciting current is sent to an electromagnetic coil 33, a fixed iron core 21 is magnetized to generate an electromagnetic sucking force, which sucks and drives a movable core 26 against a spring 28. Thus, a needle valve 27 integrated with the core 25 is moved upward, an injection hole 31 is opened to inject a fuel to the outside. As an O-ring 36 is directly interposed between a housing 26 formed by a metal and the fixed iron core 21, oil sealing property by the O-ring 36 is never affected even by a state such that the temperature is increased by the current sending to the coil 33 and this high temperature causes the deformation of a spool 32 by creeping, and the oil sealing property is certainly ensured.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to a fuel injection valve used as a fuel supply device for an internal combustion engine, and in particular to a fuel injection valve in which the amount of injected fuel is controlled by the energization time width. This invention relates to an electromagnetic fuel injection device.

[Prior Art] An electromagnetic fuel injection valve is configured to drive a movable core by supplying an exciting current to an electromagnetic coil to open a needle valve connected to the movable core.

Then, the pressurized fuel supplied to the needle valve is injected in accordance with the energization time width to the electromagnetic coil.

That is, the amount of fuel injected is controlled by the energization time to the electromagnetic coil, and is effectively used when performing electronic fuel injection control.

FIG. 7 shows an example of a conventionally known electromagnetic fuel injection valve, in which a movable core 12 is set coaxially to a fixed core 11, and a movable core 12 is set between the fixed core (l) and the movable core 12. A compression spring 13 is interposed.A spool 14 made of synthetic resin is set around the outer periphery of this fixed core 11, and an electromagnetic coil 15 is wound around this spool 14.

A metal housing 1B is provided to surround the outer periphery of the electromagnetic coil 15 and cover the entire fixed core 1t and movable core 12.
and the housing 16, and between the spool 14 and the fixed iron core 11, O-rings 1 for oil seals are provided, respectively.
7 and 18 are interposed.

In the fuel injection valve configured in this manner, magnetic flux is generated by supplying current to the electromagnetic coil 15, and an attractive force is generated between the movable iron core 11 and the movable core 12.

Therefore, the movable core 12 is moved in the direction of the fixed iron core 11 against the compression spring 13, and the needle valve 19, which is integrally provided with the movable core 12, is driven to perform a fuel injection operation. When the excitation current is cut off, the movable core 12 is moved away from the fixed core 11 by the force of the compression spring 13, and the needle valve 1
9 is closed and the fuel injection operation is stopped.

In this fuel injection valve, the fuel seal is attached to the electromagnetic coil 15.
An O-ring 17 is set between the spool 14, which is the winding frame of the housing 1B, and the fixed iron core 11.
and 18. Here, spool 14
is made of synthetic resin material. Therefore, in a high temperature state, creep occurs and deforms. For example, if the temperature of the electromagnetic coil 15 rises due to energization of the electromagnetic coil 15, the O-ring 1
7 and 18 make it difficult to secure oil seals.

[Problems to be Solved by the Invention] This invention has been made in view of the above points, and it is possible to maintain good insulation properties while maintaining oil sealing properties even when heat is generated in the electromagnetic coil. It is an object of the present invention to provide an electromagnetic fuel injection device that can be ensured and easily obtain sufficient reliability.

[Means for Solving the Problems] An electromagnetic fuel injection device according to the present invention includes a fixed core made of a magnetic material having a cylindrical shape, and a movable core set coaxially with the fixed core. , an electromagnetic coil is provided on the outer periphery of the fixed iron core. A metal housing is provided on the outer periphery of the electromagnetic coil, and a metal sealing member such as an O-ring or a cylinder made of a non-magnetic metal material is installed between the housing and the fixed iron core. Let them intervene.

[Operation] In the electromagnetic fuel injection valve configured in this way, the movable core is driven by passing an exciting current through the electromagnetic coil, and the needle valve is opened by the movable core to inject fuel. become. Since the sealing member that provides an oil seal between the housing and the fixed core does not use synthetic resin material, for example, when current is passed through the electromagnetic coil, heat is generated in the electromagnetic core. Even in cases where creep occurs, the opening of questions that would cause creep does not occur. Therefore, the reliability of the oil seal is ensured.

[Embodiments of the invention] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows its cross-sectional structure, and the fixed iron core 2i made of a cylindrical magnetic material corresponds to the central axis.
is set. A fuel passage 22 is formed in the center of the fixed iron core 21, and the end thereof is a connector pipe 23, to which pressurized fuel is supplied by an oil pump or the like (not shown). 24 is a filter that removes foreign matter contained in the fuel.

A movable core 25 made of a magnetic material is set to face the magnetic pole surface (lower end in the figure) of the fixed iron core 21 . The movable core 25 is held movably in the axial direction by a housing 26 made of metal, and a needle valve 27 is integrally connected to the distal end thereof. and,
A compression spring 28 is interposed between the movable core 25 and the fixed iron core 21 so that a force in a direction away from the fixed iron core 21 is constantly applied to the movable core 25.

Here, a nozzle body 29 is integrally provided at the end of the housing 26 in the direction in which the needle valve 27 is present.
A needle valve 27 is set in the hollow part of this nozzle body 29. A needle valve 27 is provided at the tip of the nozzle body 29.
A valve seat 30 is formed which is contacted in a state where the needle valve 27 is set away from the fixed core 21, and when the movable core 25 is moved in the direction of the fixed core 21 against the spring 28, the needle valve 27 is separated from the valve seat 30, and the fuel injection hole 31 is opened.

A spool 32 made of synthetic resin is provided on the outer periphery of the fixed core 21, and an electromagnetic coil 33 is wound around the spool 32. Here, the spool 32 wound with the electromagnetic coil 33 is configured to extend over the flange 211 of the fixed iron core 21 and extend upward in the figure, as shown in FIG. A terminal 34 is insert-molded in this extension, and the electromagnetic coil 33 is electrically connected to this terminal 34.

A signal for injection control is supplied to the terminal 34 from an electronic control device (not shown) via a wire harness, and this terminal 34 is embedded and fixed in a synthetic resin connector 35 that is integrated with the housing 26. be done.

An O-ring 36 for oil sealing is provided between the fixed iron core 21 and the housing 2B. This O-ring 3
6 is fixed in position by a ring-shaped backup member 37 made of, for example, synthetic resin.

A collar 38 is integrally provided on the needle valve 27.
This collar 38 hits a stopper 39 when the needle valve 27 moves in the direction of the fixed iron core 21, so that movement in the direction of the fixed iron core 21 is stopped.

In addition, guide portions 401 and 402 are formed in the needle valve 27 at intervals from the flange 38 in the distal direction. The guide portions 401 and 402 support the needle valve 27 so as to be movable within the fuel passage 41 formed by the hollow portion of the nozzle body 29.

FIG. 3 shows a cross-sectional structure of the guide portion 401, and the guide portion 402 is similarly constructed. That is, this guide part 401 is configured coaxially with the needle valve 27 and is movable along the axis of the needle valve 27 to guide the fuel passage 41.
A plurality of chamfered portions 421, for example, four chamfered portions 421
.about.424 form a passage communicating with the fuel injection hole 3o.

In the electromagnetic fuel injection device configured in this way, when no excitation current is supplied to the electromagnetic coil 33,
As shown in FIG. 1, the movable core 25 has a compression spring 28
It is set at a position away from the fixed iron core 21 by. At this time, the pressurized fuel supplied to the connector pipe 23 passes through the fuel passage 22 of the fixed iron core 21 and the spring 2
8 and is led to the fuel passage 41 through the movable core 25 portion.

However, when the movable core 25 is pressed by the spring 28, the needle valve 27 is seated on the valve seat 3o, so this fuel is not injected to the outside from the fuel injection hole 31.

On the other hand, when a current is supplied to the terminal 34 from an electronic control device (not shown) and an excitation current is passed through the electromagnetic coil 33, the fixed iron core 21 is magnetized, an electromagnetic attractive force is generated, and the movable core 25 is The suction drive is performed against the spring 28. Therefore, the needle valve 27, which is integral with this movable core 25, is moved upward in this figure, and the needle valve 27 is moved upward in this figure.
7 is separated from the valve seat 30, the fuel injection hole 31 is opened, and the pressurized fuel guided to the fuel passage 41 is injected from the fuel injection hole 31 to the outside.

That is, the electromagnetic coil 33 is excited and controlled by a signal current from a control device (not shown) supplied to the terminal 34, and a fuel injection operation is performed while the signal current is supplied. Therefore, fuel injection control is performed in an amount corresponding to the supply time width of this signal current.

In such a fuel injection device, the temperature in the engine room tends to rise as the engine output becomes higher and the engine room becomes more compact. Further, this fuel injection device itself is required to be downsized, and therefore the radiation area of the heat generated by the electromagnetic coil 33 tends to become smaller, and the temperature of the electromagnetic coil 33 also tends to rise. Therefore, in the conventional configuration shown in Fig. 7, the spool made of synthetic resin deforms due to creep in this high temperature state, and if an O-ring is installed in this spool part, it is difficult to secure an oil seal. I can't.

However, in the fuel injection device shown in the above embodiment,
Housing 26 and fixed core 21 made of metal
An O-ring 3G is directly interposed between the two. Therefore, even if the spool 32 is deformed due to creep due to high temperatures, the O-ring 3
It does not affect the oil sealing property due to 6 at all,
The oil seal is securely secured.

Further, in this embodiment, the joint between the electromagnetic coil 33 and the terminal 34 is configured to be exposed above the figure, which is outside the magnetic circuit section including the electromagnetic coil 33. Therefore, the magnetic circuit section can be shortened and configured, which is effective in improving efficiency.

Furthermore, the fuel injection valve device itself can be downsized.

FIG. 4 shows another embodiment. In this embodiment, a pipe 51 made of a non-magnetic material is attached to the outer periphery of the fixed iron core 21 by means such as brazing. An O-ring 36 is interposed between the vibrator 51 and the housing 26 to form an oil seal.

Further, the embodiment shown in FIG. 5 includes a vibrator 52 made of a non-magnetic material, which has a cylindrical body 5211 that fits into the outer periphery of the fixed iron core 21, and a collar 522 whose outer periphery comes into contact with the inner periphery of the housing 2B. The pipe 52 is connected to the fixed iron core 21 and the yoke 53 by brazing, etc., respectively. This vibrator 52 constitutes an oil seal.

In the embodiment shown in FIGS. 4 and 5 above, the means for connecting the vibrators 51 and 52 to other members is as follows:
Diffusion bonding may be used, or laser welding (full circumference welding) may be used.

In this case, the vibrator 51.52 used as a sealing member
The shape of the sealing member can be set as appropriate. For example, the sealing member can be formed by a pipe 54 having a fold as shown in FIG. In this case, by attaching a backup member 55 made of a non-magnetic fully bending material to the inside of the folded portion of the pipe 54, the structural strength can be stabilized.

In the embodiment shown in FIGS. 4 to 6, the same components as those in the embodiment shown in FIG.

[Effects of the Invention] As described above, according to the electromagnetic fuel injection device according to the present invention, even if a current flows through the electromagnetic coil and generates heat, the oil seal member is made of a synthetic resin material, such as a spool, etc. Since the synthetic parts of the oil seal come into contact with each other and are not involved in the oil seal, the reliability of the oil seal can be ensured, especially in high-temperature conditions. It is possible to configure this fuel injection a= by miniaturizing the device, which is effective in improving the functionality of the fuel injection device, and makes it easy to create a small and highly reliable fuel injection device. It will be possible to configure

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a cross-sectional diagram illustrating an electromagnetic fuel injection device according to an embodiment of the present invention, and Fig. 2 shows a portion related to the electromagnetic coil of the above embodiment. Figure 3 is the first
4 to 6 are sectional views showing other embodiments of the present invention, and FIG. 7 is a sectional view showing a conventional fuel injection device. 21... Fixed iron core, 22... Fuel passage, 25...
Movable core, 26... Housing, 27... Needle valve, 28... Spring, 29... Nozzle body,
30... Valve seat, 31... Fuel injection hole, 32... Spool (made of synthetic resin), 33... Electromagnetic coil, 34...
...Terminal, 36...O ring, 37.53...
・Backup member, 51.52.54...pipe (
non-magnetic materials).

Claims (4)

[Claims] (1) A cylindrical fixed core made of magnetic material that is set along the central axis, and a cylindrical fixed core that is set opposite to the tip magnetic pole surface of this fixed core and is movable in a direction away from or toward this fixed core. a movable core made of a magnetic material; a spring interposed between the movable core and the fixed iron core to apply a force in a direction away from the fixed iron core on the movable core; and a spring applied to the fixed iron core. an electromagnetic coil provided on an outer peripheral portion; a cylindrical housing made of a metal material configured to surround the electromagnetic coil portion, the fixed iron core, and the movable core portion; and the housing and the fixed iron core. an electromagnetic fuel injection device, further comprising a metal sealing member interposed between the housing and the fixed core, the housing and the fixed core being directly connected by the sealing member. . (2) The electromagnetic fuel injection device according to claim 1, wherein the sealing member is an O-ring. (3) The electromagnetic fuel injection device according to claim 1, wherein the sealing member includes a non-magnetic metal cylindrical body set in contact with the outer periphery of the fixed core. (4) The electromagnetic fuel injection device according to any one of claims 1, 2, and 3, wherein a joint between the electromagnetic coil and the terminal is formed outside the magnetic circuit.