JP2969763B2 - Electromagnetic fuel injection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection device used as a fuel supply device for an internal combustion engine, and more particularly to an improved fuel seal structure.

[Background Art] An electromagnetic fuel injection device used in an internal combustion engine drives a movable core by passing an exciting current through an electromagnetic coil wound around a fixed iron core, and drives a needle valve with the movable iron core. Is configured to inject fuel set to a predetermined pressure state.

FIG. 4 shows an example of a conventional electromagnetic fuel injection device.
It is disclosed in Japanese Patent No. 166662.

The fuel injection device includes a fixed core 12 having a fuel passage 11 formed in an axial portion along a central axis.
The movable iron core 13 is set coaxially with the movable iron core 13. This movable iron core
Numeral 13 is set so as to be movable to two positions, that is, a state close to the magnetic pole face at the end face of the fixed iron core 12 and a state separated from the magnetic pole face. Is set at a position away from

On the outer peripheral portion of the fixed core 12 and the movable iron core 13 arranged coaxially, a spool 15 serving as a coil holding member formed of an insulator while being coupled to the outer periphery of the fixed iron core 12 is provided.
The electromagnetic coil 16 is wound around the outer periphery of the spool 15. Then, on the outer peripheral portion of the electromagnetic coil 16,
A housing 17 is formed, a first O-ring 18 is interposed between the fixed iron core 12 and the spool 15, and further, the spool 15 and the housing 17 are provided corresponding to the position of the movable iron core 13.
And a second O-ring 19 interposed therebetween.

The first and second O-rings 18 and 19 function as fuel sealing members, and seal between the spool 15 and the fixed iron core 12 and between the spool 15 and the housing 17.

Here, the spool 15 is generally made of synthetic resin, and in response to the demand for downsizing and diameter reduction of the fuel injection valve, the volume of the electromagnetic coil 16, particularly the radial thickness, is reduced. Reduction is required.

However, if the radial thickness of the electromagnetic coil 16 is reduced in response to this requirement while maintaining the thickness of the O-rings 18 and 19 constituting the seal member, the thickness of the spool 15 is also reduced, The rigidity becomes significantly insufficient.
Further, since the volume of the coil 16 is reduced, the heat generated by the coil 16 tends to cause a high temperature state. Under such a high temperature condition, the rigidity of the spool 15 made of synthetic resin is weakened, and in particular, the second O-ring 19 which does not have a strong backup due to the fixed iron core 12 is deformed by creep. . Therefore, this second
It is difficult to secure the fuel sealing state in the O-ring 19 portion.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and even if the electromagnetic coil portion is reduced in volume by reducing its volume, the function of the oil seal portion is surely ensured. It is an object of the present invention to provide an electromagnetic fuel injection device that can exhibit a highly reliable fuel injection operation.

[Means for Solving the Problems] In an electromagnetic fuel injection device according to the present invention, a coil holding member is set on the outer periphery of a fixed iron core and a movable iron core arranged coaxially, and an electromagnetic coil is attached to the coil holding member. A cover member is provided in a state where the coil holding member is wrapped around the outer periphery of the electromagnetic coil, and a housing is formed on the outer periphery of the cover member. The cover member is fixed to the cover member at a position where the fixed core exists. First and second seal members are interposed and set between the iron core and the cover member and the housing, respectively.

[Operation] In the electromagnetic fuel injection device configured as described above,
First and second seal members are provided between the cover member of the electromagnetic coil and the fixed core, and between the housing and the housing. The first and second seal members are provided with a rigid fixed core and It is interposed between the housing and the housing, and is backed up by the rigid fixed core and the housing, thereby ensuring sufficient sealing performance. Therefore, the configuration is such that the volume of the electromagnetic coil portion is reduced, and even if the coil holding member and the cover member are heated to a high temperature state due to the heat generated by the coil portion, these members are not deformed by creep, and their reliability is improved Sex is sufficiently ensured.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration, in which a fixed iron core 21 made of a magnetic material is set corresponding to the central axis. The fixed core 21 is formed in a cylindrical shape, and a fuel passage 22 is formed in an axial portion thereof.
A connector tube 23 is provided at an entrance portion of 22. Although not shown in detail, fuel pressurized by an oil pump or the like is supplied to the connector tube 23. A filter 24 is attached to the connector tube 23, and the filter
24 removes foreign substances and the like contained in the fuel.

The opposite side of the fixed core 21 from the connector tube 23 (the lower end in the figure) is a magnetic pole surface.
25 is set opposite. The movable iron core 25 is made of a magnetic material and is set to be coaxial with the fixed iron core 21. The movable iron core 25 can move to a position close to the magnetic pole surface of the fixed iron core 21 and to a position separated from the magnetic pole surface. The needle valve 27 is integrally connected to the tip of the movable iron core 25.

A compression spring 28 is interposed between the fixed iron core 21 and the movable iron core 25, and a force in a direction away from the magnetic pole surface of the fixed iron core 21 is constantly applied to the movable iron core 25. .

A valve body 29 is integrally connected to an end of the housing 26 in the direction in which the needle valve 27 exists, and the needle valve 27 is set in a hollow portion of the bubble body 29.
At the tip of the valve body 29, a valve seat is contacted in a state where the needle valve 27 is set at a position away from the fixed iron core 21.
When the movable iron core 25 is moved in the direction of the fixed iron core 21 against the spring 28, the needle valve 27 separates from the valve seat 30, and the fuel injection hole 31 is opened.

A spool 32 made of a synthetic resin is provided on the outer periphery of the fixed iron core 21. The spool 32 serves as a coil holding member, and an electromagnetic coil 33 is wound around the outer periphery of the spool 32. The spool 32 is formed so as to extend over the flange 211 of the fixed iron core 21 and to extend upward. A terminal 34 is inserted into an extension of the spool 32, and an electromagnetic coil 33 is electrically connected to the terminal 34 so that an exciting current supplied through the terminal 34 flows through the electromagnetic coil 33. .

That is, a current signal for injection control is supplied to the terminal 34 from an electronic control unit (not shown) via a wire harness.
It is embedded and set in a synthetic resin connector 35 integrally formed with the connector 35.

A cover 36 made of a synthetic resin is further formed on the outer peripheral portion of the electromagnetic coil 33. That is, the electromagnetic coil 33 is set to be inserted between the spool 32 and the cover 36.

Here, a first O is provided between the cover 36 and the fixed iron core 21.
A second O-ring 38 is provided between the housing 36 and the cover 36 corresponding to the position of the fixed iron core 21 with a ring 37 interposed therebetween.
Is set to intervene. The first and second O-rings 37 and 38 are used for an oil seal.

The needle valve 27 is provided with a flange 39 integrally,
The flange 39 hits the stopper 40 when the needle valve 27 moves in the direction of the fixed core 21, and the fixed core 21 of the needle valve 27
The movement in the direction of is stopped. Guide portions 411 and 412 are formed on the needle valve 27 at a predetermined distance from the flange 39 in the distal direction. This guide 4
Reference numerals 11 and 412 constitute a support mechanism in which the needle valve 27 is movably set in a fuel passage 42 formed by a hollow portion of the valve body 29.

In the fuel injection device configured as described above, when the exciting current is not supplied to the electromagnetic coil 33, the movable core
25 is set at a position separated from the magnetic pole surface of the fixed iron core 21 by the force of the spring 28. At this time, the pressurized fuel supplied to the connector pipe 23 is guided to the fuel passage 42 of the valve body 29 through the fuel passage 22, the room where the spring 28 is set, and further through the movable core 25. . However, when the movable iron core 25 is separated from the magnetic pole surface of the fixed iron core 21, the needle valve 27 is seated on the valve seat 30, and therefore, the fuel guided to the fuel passage of the valve body 29 is supplied to the fuel injection hole. It is not injected outside from 31.

When a current is supplied to the terminal 34 from an electronic control unit (not shown) and an exciting current flows to the electromagnetic coil 33, the fixed iron core 21 is magnetized and the movable iron core 25 is attracted and driven against the spring 28. Accordingly, the needle valve 27 is moved together with the movable iron core 25, the needle valve 27 is separated from the valve seat 30, the fuel injection hole 31 is opened, and the pressurized fuel is injected.

That is, the excitation of the electromagnetic coil 33 is controlled by the signal current from the electronic control unit, and the fuel injection operation is executed while the signal current is being supplied.

With the increase in the output of an internal combustion engine (engine) and the downsizing of a room (engine room) accommodating the internal combustion engine, the temperature in this room tends to increase. In addition, miniaturization of the fuel injection device itself is required, and electromagnetic coils 33
The heat radiation area of the heat generated by the
The temperature of the portion 33 also increases, the temperature of the spool 32 supporting the electromagnetic coil 33 also increases, and creep easily occurs.

However, the fuel injection device shown in the embodiment has a structure in which O-rings 37 and 38 are arranged between the housing 26 made of metal and the fixed iron core 21. Therefore, even when the spool 32 and the cover 36 integral therewith are in a state of creeping due to high temperature,
Rings 37 and 38 are fixed iron cores 21 each made of metal.
And the housing 26 is backed up, so that there is little effect on the oil sealability, and the oil seal is reliably ensured.

Also. In the fuel injection device shown in this embodiment,
A gap between the fixed iron core 21 and the movable iron core 25 can be arranged at a position close to the center of the electromagnetic coil 33, so that it can be effective for improving the operation efficiency, and the size can be reduced. It is measured.

FIG. 2 shows another embodiment. In this embodiment, a fixed core 21 of the electromagnetic coil 33 is provided on a spool 32 around which an electromagnetic coil 33 is wound and a cover 36 on the outer periphery of the electromagnetic coil 33. A groove is formed between the fixed core 21 and the housing 26 at the side in the extending direction, and the first O-ring 37 and the second O-ring 37 are formed in the groove, respectively.
O-ring 38 is embedded. That is, the first O-ring 37 is backed up by the fixed iron core 21, and the second O-ring 37 is
38 is backed up by housing 26, spool
Even if the temperature of the cover 32 and the cover 36 becomes high, the oil sealing property is reliably ensured.

In this embodiment, the spool 32 is first formed by molding, the electromagnetic coil 33 is wound around the spool 32, and then the cover 36 is formed. The lower portion 361 is joined by, for example, welding, ultrasonic welding, bonding or the like.

In the embodiment shown in FIG. 3, the electromagnetic coil 331 is constituted by a coil wire having a flat shape such as a rectangular or oval cross section. That is, the electromagnetic coil 331 is configured by laminating a coil wire having a flat cross section on the outer periphery of the spool 32 in a cylindrical shape.

In this case, both ends of the electromagnetic coil 331 made of flat coil wires laminated in a cylindrical shape are arranged so as to be sandwiched by, for example, flattened terminal wires 341 and 342, and connected to both ends of the coil 331 by welding or the like. To do.

Here, the spool 32 and the cover 36 with respect to the electromagnetic coil 331 are, for example, assembled and set at a predetermined position with the coil 331 formed by lamination, and then the coil 331 and the fixed core 2 are mounted.
It can be constituted by insert-molding a resin between 1 and the housing 26.

If the electromagnetic coil portion is improved in this manner, the winding operation of the coil portion becomes easier, and the weldability with the terminal is also improved, so that the fuel injection device is greatly reduced in size. In this case, the first and second O-rings 37 and 38 constituting the oil seal structure are provided.
Can be backed up by the fixed iron core 21 or the housing 26, the spool 3
The problem that the temperature of the cover 2 and the cover 36 becomes high and the oil sealing property is adversely affected is also solved at the same time.

[Effects of the Invention] As described above, according to the electromagnetic fuel injection device of the present invention, the oil seal structure is constituted even when heat is generated by reducing the volume of the electromagnetic coil unit, for example. There is no deformation such as creep in the portion supporting the O-ring, the oil seal is reliably ensured, and a highly reliable electromagnetic fuel injection device that meets the demand for downsizing can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view illustrating an electromagnetic fuel injection device according to one embodiment of the present invention, FIGS. 2 and 3 are sectional views showing another embodiment of the present invention, and FIG. FIG. 9 is a cross-sectional configuration diagram illustrating a conventional fuel injection device. 21 …… Fixed iron core, 25 …… Movable iron core, 26 …… Housing,
27 ... Needle valve, 28 ... Spring, 32 ... Spool, 33, 331 ... Electromagnetic coil, 36 ... Cover, 37 ... First O-ring, 38 ... Second O-ring.

Claims (4)

(57) [Claims] A fixed core fixedly set in accordance with an axis; and a coaxially arranged fixed core and moving to a position close to a magnetic pole surface of the fixed core and a position away from a magnetic pole surface of the fixed core. A movable core that is set to be capable of being subjected to a spring force in a direction away from the fixed core, a coil holding member made of an insulator formed to surround an outer peripheral portion of the fixed core, and a coil holding member. An electromagnetic coil wound around the electromagnetic coil, a cover member made of an insulator formed so as to wrap the electromagnetic coil and the coil holding member, and a coil component configured to include the electromagnetic coil, the coil holding member, and the cover member A first seal member interposed between the cover member and the fixed iron core; and a first seal member interposed between the cover member and the fixed iron core. And a second seal member interposed between the cover member and the housing. 2. A fixed iron core fixedly set in accordance with an axis, and arranged to be coaxial with the fixed iron core and moved to a position approaching a magnetic pole surface of the fixed iron core and a position apart from a magnetic pole surface of the fixed iron core. A movable core that is set to be capable of being subjected to a spring force in a direction away from the fixed core, a coil holding member made of an insulator formed to surround an outer peripheral portion of the fixed core, and a coil holding member. An electromagnetic coil wound around the electromagnetic coil; a cover member made of an insulator formed so as to further surround the electromagnetic coil; wherein the coil holding member and the cover member are integrally formed so as to surround the electromagnetic coil. A housing formed so as to surround a coil component configured to include the electromagnetic coil, the coil holding member, and the cover member; and the holding portion. A first seal member interposed and set between a member and the fixed iron core; and a second seal member interposed and set between the cover member and the housing at an outer peripheral portion of the fixed iron core. An electromagnetic fuel injection device, comprising: 3. The electromagnetic coil is wound around an outer periphery of the coil holding member, and the cover member is formed around an outer periphery of the wound electromagnetic coil. 3. The electromagnetic fuel injection device according to claim 2, wherein the member and the cover member are connected to each other. 4. The electromagnetic coil is formed by a coil wire having a flat cross section, and is wound around an outer periphery of the coil holding member so as to sequentially overlap in a direction of an axis of the fixed iron core. The electromagnetic fuel injection device according to any one of claims 1 to 3, wherein the cover member is formed on the electromagnetic fuel injection device.