JP2508553Y2 - electromagnet - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an EI type electromagnet used in an electronically controlled fuel injection device for a diesel engine.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIG. FIG. 5 is a structural explanatory view of an electronically controlled fuel injection device used in a conventional diesel engine. 5A is a sectional view of the injector, and FIG. 5B is a sectional view of the cracked solenoid stator. In the figure, 1 is a plunger, 2
Is a poppet valve, and 3a is a plunger chamber in which the plunger 1 reciprocates in the injection valve body. A spacer 4 covers the end of the plunger chamber 3a. A fuel passage 4a penetrates the spacer 4. 11 is a fuel nozzle. A needle valve 10 is provided between the fuel passage 4 a and the fuel nozzle 11. 8 is a spring (push spring)
The needle valve 10 is pressed against the valve seat. A fuel passage 3b communicates the plunger chamber 3a with the valve rod side chamber of the poppet valve 2. 3f is an oil drain opening to the outside of the injection pump. 3c is an oil sump and the poppet valve 2
It communicates with the oil discharge port 3f in the chamber on the valve umbrella side. 12a
Is an E-shaped iron core, 12b is a bobbin, and E of the iron core 12a
It fits in the middle leg of the glyph. A solenoid winding 12c is wound around the bobbin 12b. Reference numeral 12d is a thermosetting resin that covers the outside of the iron core 12a. A solenoid stator 12 is composed of the iron core 12a, the bobbin 12b, the solenoid winding 12c, and the thermosetting resin 12d.

Reference numeral 13 is an armature plate-shaped iron having a hole, which is provided in a floating manner so as to face the leg of the iron core 12a and is vertically fixed to the end of the valve rod of the poppet valve 2. A solenoid spacer 14 is provided in contact with the end surface of the thermosetting resin 12d. Reference numeral 15 is a spring (pushing spring) which urges the poppet valve 2 in a direction away from the valve seat via a spring receiver, and the spring receiver contacts a wall and stops. Reference numeral 20 denotes an armature chamber which is enclosed inside the solenoid spacer 14 and communicates with the chamber having the spring 15. 3e
Communicates the chamber having the spring 15 with the oil discharge port 3f through a communication passage. 3d supplies the fuel supplied from the fuel passage to the drain oil sump 3c.

Next, the operation of the conventional example will be described with reference to FIGS.
Will be described with reference to. This fuel injection device used in a conventional diesel engine uses an electromagnet to make the injection amount and injection timing of the fuel independent and accurately control them by electronic control. Since the poppet valve 2 is always away from the valve seat, the plunger 1 is descending, and the fuel in the plunger chamber 3a is discharged through the fuel passage 3b, between the poppet valve 2 and the valve seat, and through the oil sump 3c. .
When the solenoid winding 12c is energized by a control device (not shown), the iron core 12a is magnetized and attracts the armature 13, so that the poppet valve 2 is pulled together in the valve rod direction and seated, and the sump 3c of the fuel passage 3b is seated. Since the communication with the plunger chamber 3a is closed, the fuel in the plunger chamber 3a is compressed, the pressure thereof acts on the tip of the needle valve 10 through the fuel passage 4a, and the pressure overcomes the force of the spring 8 to reach the needle. The valve 10 is pushed up and jetted from the nozzle 11.

When the current to the solenoid winding 12c is cut off by a control device (not shown), the force of pulling the armature 13 disappears, so that the poppet valve 2 leaves the valve seat by the force of the spring 15 and the fuel passage 3b leaves the oil sump 3c. And the high-pressure plunger chamber 3a communicates with the oil sump 3c through the fuel passage 3b.
The pressure drops and the needle valve 10 loses the force of the spring 8 to close and fuel injection stops. When the plunger 1 goes up, the fuel supplied from the fuel passage 3d to the oil sump 3c flows into the plunger chamber 3a through the fuel passage 3b to fill up the fuel. The pressure in the armature chamber 20 is approximately equal to the fuel supply pressure of 1 to 6 kgf / cm ² when the poppet valve 2 is closed.
When the poppet valve 2 starts to open, the high-pressure fuel flowing out from the poppet valve 2 flows into the armature chamber 20 through the drain oil sump 3c and the communication passage 3e, and the pressure in the armature chamber 20 is increased. The pressure in the armature chamber 20 is 100 kg when the fuel injection pressure is 1000 kgf / cm ² or more.
It may be f / cm ² .

[0006]

In the fuel injection device of the above-mentioned prior art, there is a gap of 5 to 40 μm at the interface between the fixed iron core and the resin enclosing the fixed iron core, and the pressure of the armature chamber to this gap. The fuel of 30 to 120 kgf / cm ² enters and pushes between the iron core and the resin, and the resin cannot withstand this force and cracks, which may cause the fuel to flow out to the outside.

The object of the present invention is to solve the above problems of the conventional apparatus, to cover the resin covering the iron core with a metal box, and to generate cracks by the pressure of the fuel that has penetrated into the gap 12f ₁ between the iron core and the resin. The purpose is to provide an E-shaped electromagnet having a structure that does not exist.

[0008]

The electromagnet of the present invention is an EI type electromagnet used in an electronically controlled fuel injection device for a diesel engine, the outer side of which is layered E-shaped electromagnetic iron plates whose surfaces are electrically insulated. Cover with a metal box such as aluminum and fill the gap between the iron core and the metal box with resin,
An O-ring is provided between the winding attached to the iron core, the conductive connection terminal, and the metal box.

[0009]

As described above, since the resin 12d is largely reinforced by the metal box 12e, the resin 12d can withstand the force of pushing open the interface 12f ₁ between the iron core 12a and the resin 12d, and the resin 12d
No crack occurs in d. Even if a crack occurs in the resin 12d, the O-ring 12f is installed, so the fuel will not flow out.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electromagnet of the present invention will be described with reference to FIGS. 1 to 4 and 5 (a). 1 and 2 are structural explanatory views of an electromagnet of an embodiment according to the present invention. 3 and 4 are explanatory views of the operation of the fuel injection device. The structure of the fuel injection device is the same as that of the conventional example except for the electromagnet, so that FIG. 5A will be referred to. The fuel injection device of this embodiment is used for a diesel engine, and an electromagnetic valve is used to make the injection amount and injection timing of fuel independent and to be controlled accurately by electronic control. 1 in the figure
Is a plunger and 2 is a poppet valve which is always separated from the valve seat. 3 is an injection valve main body, 3a is a plunger chamber in which the plunger 1 reciprocates. A fuel passage 3b connects the plunger chamber 3a with the valve rod side chamber of the poppet valve 2. 3f is an oil drain opening to the outside of the injection pump. Reference numeral 3c denotes an oil drain reservoir, which is a chamber on the valve cap side of the poppet valve 2 and communicates with the oil drain port 3f. A spacer 4 closes the tip of the plunger chamber 3a. A fuel passage 4a is provided in the spacer 4 and penetrates therethrough. 11 is a fuel nozzle. A needle valve 10 is provided at the center of the fuel nozzle. Reference numeral 8 is a spring for pressing the needle valve against the valve seat.

An iron core 12a has an E shape. 12b
Is a bobbin and is fitted in the E-shaped central leg of the iron core 12a. A solenoid winding 12c is wound around the bobbin 12b. 12e is a metal box made of aluminum or the like, which covers the iron core 12a, and a resin 12 is provided in a gap between the iron core and the metal box.
An O-ring 12f is installed between the metal box and the winding, which is filled with d and is attached to the iron core 12a, and the conductive connection terminal. 12 is a solenoid stator, which is the iron core 12
a, the bobbin 12b, the solenoid winding 12c, the thermosetting resin 12d, the metal box 12e, the connection terminal 12g, O
It is composed of a ring 12f and the like.

Numeral 13 is a rectangular plate-shaped iron with an armature, which is provided so as to be opposed to the solenoid stator 12 and is vertically fixed to the valve rod of the poppet valve 2. A solenoid spacer 14 is provided in contact with the thermosetting synthetic resin 12d and the metal box 12e. 1
Reference numeral 5 denotes a spring (pushing spring) which urges the poppet valve 2 in a direction away from the valve seat via a spring receiver, and the spring receiver contacts a wall and stops. Reference numeral 20 denotes an armature chamber surrounded by the solenoid spacer 14 and having an armature 13 therein.
And communicates with the chamber in which the spring 15 is located. A communication passage 3e connects the chamber in which the spring 15 is provided and the oil drain port 3f. 3d is a fuel passage, which is a fuel supply port and the drain sump 3
It communicates with c.

Next, the operation of the above embodiment will be described.
Since the poppet valve 2 is always separated from the valve seat, the fuel in the plunger chamber 3a is pushed out while the plunger 1 is descending, and the fuel passage 3b passes between the poppet valve 2 and the valve seat, and the sump oil sump 3c
Has been discharged to. When the solenoid winding 12c is energized by a control device (not shown), the iron core 12a is magnetized and attracts the armature 13, so that the poppet valve 2 is also pulled toward the valve stem, hits the valve seat, closes the valve, and exhausts from the fuel passage 3b. The communication of the oil reservoir 3c is cut off, the plunger chamber 3a is sealed, the pressure rises due to the lowering of the plunger 1, this pressure acts on the tip of the needle valve 10 through the fuel passage 4a, and this pressure overcomes the force of the spring 8. The fuel in the plunger chamber 3a is injected from the fuel nozzle 11 by pushing up the needle valve.

When the current to the solenoid winding 12c is cut off, the magnetism of the iron core 12a disappears and the force to pull the armature 13 disappears. Therefore, the poppet valve 2 leaves the valve seat by the force of the spring 15 and the fuel passage 3b collects in the oil sump. 3c, the plunger chamber 3a communicates with the drain oil sump 3c through the fuel passage 3b, the pressure drops, the force of the spring 8 wins, and the needle valve 10 closes.
The injection is stopped, and the fuel in the plunger chamber 3a is discharged to the drain port 3f through the fuel passage 3b and the drain oil reservoir 3c. When the plunger 1 goes up, the fuel supplied to the drain oil sump 3c through the fuel passage 3d at a pressure of 1 to 6 kgf / cm ² flows into the plunger chamber 3a through the fuel passage 3b and fills up. The pressure in the armature chamber 20 is ₁ to 6 kgf / cm ^{2 in the} fuel supply chamber after the poppet valve 2 is closed at time t _1.
become. When the poppet valve 2 starts to open at time t ₂ , the high-pressure fuel passes between the poppet valve 2 and the valve seat, flows into the armature chamber 20 through the drain oil sump 3c and the communication passage 3e, and increases the pressure in the armature chamber 20. Let Fuel injection pressure is 10
When the pressure is over 00 kgf / cm ^2, the pressure in the armature chamber 20 is 1
It may be over 00 kgf / cm ² . Armature room 2
The fuel of 0 penetrates into the gap at the interface 12f ₁ between the iron core 12a and the thermosetting synthetic resin 12d and applies an outward force to the resin 12d, but the outside of the thermosetting resin 12d of this embodiment is the metal box 1
Since it is tightly covered and reinforced with 2e, it does not crack as in the conventional case.

[0015]

The resin for hardening the outer side of the electromagnet of the present invention is reinforced by the metal box as described above, so that cracks do not occur even if fuel pressure acts on the gap between the iron core and the resin.
Therefore, the present invention can provide an E-shaped electromagnet whose outer portion is hardened with a synthetic resin that does not crack due to insufficient strength.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an electromagnet according to an embodiment of the present invention.

FIG. 2 is a view on arrow A in FIG.

FIG. 3 is an operation explanatory view of the fuel injection device. (A) The figure of a plunger descending poppet valve closing, (b) The figure of a plunger descending poppet valve opening, (c) The figure of a plunger raising poppet valve opening.

FIG. 4 is a diagram showing the movement and pressure of the valve of the injection valve according to the embodiment of the present invention.

FIG. 5 is a structural explanatory view of a conventional injection device. (A) Sectional drawing of an injection device. (B) A sectional view of a solenoid stator having a crack in resin.

[Explanation of symbols]

12 Solenoid stator 12a Iron core 12d Resin 12e Metal box 12f O-ring 12f ₁ Interface between resin and metal box 12g Connection terminal

Claims (1)

(57) [Scope of utility model registration request] 1. An electromagnet used in an electronically controlled fuel injection device for a diesel engine, wherein an outer surface of an iron core, in which electromagnetic steel sheets whose surfaces are electrically insulated, are laminated in layers, is covered with a metal box such as aluminum. An electromagnet characterized in that a gap is filled with a resin in the metal box, and an O-ring is provided between the metal box and the connection terminal that is electrically conductive to the winding in which the iron core is assembled.