JPH04358763A - Electromagnetic type fuel injection valve - Google Patents

Abstract

PURPOSE:To provide an electromagnetic type fuel injection valve excellent in corrosion resistance and responsiveness at the time of opening/closing a valve, easy in processing, and manufacturable inexpensively. CONSTITUTION:A reciprocating needle valve 8 is guided, movably in a shaft direction, to a guide hole 7 of a valve main body 2. The valve main body 2 has a valve seat part 6 on which the needle valve 8 can abut and a nozzle 5. When an electromagnetic coil 26 is electrified, the needle valve 8 is moved to a fixed iron core 25 side in a valve-opening direction by electromagnetic attracting force against a returning coil spring 28. A cylindrical housing 50, housing the electromagnetic coil 26, has a slit 50a so as to be nonconductive in the peripheral direction of the housing 50, and is formed by cylindrically bending a plate material. This restrains the generation of overcurrent, improving responsiveness at the time of valve opening/closing action by strong electromagnetic attracting force.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic fuel injection valve used in a fuel supply system for an internal combustion engine, and more particularly to the structure of a housing of an electromagnetic fuel injection valve.

0002

[Prior Art] Conventionally, as shown in Japanese Patent Publication No. 58-54263, a needle valve is lifted against the urging force of a spring by an electromagnetic attraction force generated when an electromagnetic coil is energized, and a nozzle body is Electromagnetic fuel injection valves that inject fuel from holes are known. The housings of such fuel injection valves have traditionally been made of low-carbon steel, which is relatively easy to process and inexpensive, but in recent years, electromagnetic stainless steel has been increasingly used to improve corrosion resistance and responsiveness. ing. Furthermore, the housing of the injection valve disclosed in Japanese Utility Model Application Publication No. 56-41154 uses ferrite to reduce the generation of eddy currents in order to improve responsiveness.

0003

[Problems to be Solved by the Invention] However, with such conventional electromagnetic fuel injection valves, if the housing is made of low carbon steel, problems arise such as corrosion caused by the fuel and a decrease in response due to the generation of eddy currents. Cheap. In addition, in cases where the housing is made of electromagnetic stainless steel, chromium is
Since the content is a few percent, there is a problem that it is difficult to process and the material cost tends to be high.Furthermore, it is difficult to use a large amount of expensive ferrite as the constituent material of the housing. The present invention has been made to solve these problems, and an object of the present invention is to provide an electromagnetic fuel injection valve that is excellent in corrosion resistance and responsiveness when opening and closing the valve, is easy to process, and can be manufactured at low cost. do.

0004

[Means for Solving the Problems] An electromagnetic fuel injection valve according to the present invention for solving the above problems includes a valve member capable of reciprocating movement, a guide hole for guiding the valve member so as to be movable in the axial direction, and a guide hole for guiding the valve member so as to be movable in the axial direction. a valve body having a valve seat portion and an injection hole that can be brought into contact with a valve member; a biasing device that biases the valve member in a valve closing direction;
an electromagnetic coil that moves the valve member in a valve opening direction by an electromagnetic attraction force against the urging means; and a cylindrical housing that accommodates the electromagnetic coil, the housing being non-conductive in the circumferential direction. It is characterized by comprising a housing having a slit and formed by bending a plate material into a cylindrical shape.

[0005]

[Operation] According to the fuel injection valve of the present invention, it is possible to use materials such as electromagnetic stainless steel with good corrosion resistance for the component parts that come in contact with fuel, and for the housing part for the electromagnetic coil that does not come into contact with fuel. Since the structure is made of an inexpensive material such as low carbon steel and has no conduction in the circumferential direction, eddy currents can be reduced and responsiveness of valve opening/closing operations can be improved.

[0006]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. 1 to 3 show a first embodiment of an electromagnetic fuel injection valve that supplies fuel to an intake pipe of a spark ignition internal combustion engine mounted on a vehicle. As shown in FIG. 1, an electromagnetic fuel injection valve 1 has a valve body 2 made of martensitic stainless steel and a valve case 3 made of austenitic stainless steel, and the tip of the valve case 3 is bent to form a valve. By pressing against the main body 2, the valve main body 2 and the valve case 3 are integrally connected. The cap 4 coupled to the outer periphery of the valve body 2 includes:
An injection hole 5 for injecting and supplying metered fuel to the intake pipe is formed, and a truncated conical valve seat 6 is formed in the valve body 2. A needle valve 8 made of martensitic stainless steel is inserted into the guide hole 7 opened in the axial direction of the valve body 2.
is housed so as to be movable in the axial direction, and the conical slope 8a of the needle valve 8 can come into contact with the valve seat 6. The needle valve 8 is provided with a first sliding part 9 and a second sliding part 10 spaced apart from each other in the axial direction, and the first sliding part 9 is connected to the guide hole 7.
It is fitted to the inner wall surface of the housing so that it can slide smoothly in the axial direction through a gap of several microns.

A disc-shaped distance piece 12 is fitted and fixed between the rear end of the needle valve 8 and the valve case 3, and when the flange 13 provided on the needle valve 8 comes into contact with the distance piece 12, The fully open position of the needle valve 8 is determined. The rear end of the needle valve 8 passes through the inner hole 12a of the distance piece 12 and extends into the valve case 3. An electromagnetic actuator 16 is provided at the upper part of the valve case 3 in FIG. 1 for driving the needle valve 8 to move the conical slope 8a of the needle valve 8 between a closed position and an open position. Electromagnetic actuator 16
includes an armature 18 made of a magnetic material connected to the rear end of the needle valve 8, a spool 22 made of synthetic resin fixed to the valve case 3 via an O-ring 20, and an O-ring 23 attached to the spool 22. It has a fixed iron core 25 made of a magnetic material that is fixed through the spool 22, and an electromagnetic coil 26 that is wound around the spool 22.

The armature 18 is urged in the closing direction, that is, downward in FIG. 1, by a return coil spring 28. When current is supplied to the electromagnetic coil 26, an electromagnetic force is generated, and the armature 18 is attracted to the fixed iron core 25 against the biasing force of the return coil spring 28. When the armature 18 is attracted to the fixed iron core 25, when the flange 13 comes into contact with the distance piece 12, the needle valve 8 is at the open position. When the supply of current to the electromagnetic coil 26 is stopped, the armature 18 moves away from the fixed iron core 25 due to the biasing force of the return coil spring 28, and the conical slope 8a of the needle valve 8 touches the valve seat 6. The abutment places the needle valve 8 in the closed position. The electromagnetic coil 26 is connected to an electronic control circuit (not shown) via a terminal 34 housed in a connector 35, and the electromagnetic coil 26 is connected to an electronic control circuit (not shown) by a command from the electronic control circuit.
6 is controlled.

The flange 36 of the fixed iron core 25 is fixed to a connector 35 made of synthetic resin. A filter 40 is provided in the joint portion 38 that integrally extends rearward from the flange 36, and an adjusting pipe 42 for adjusting the urging force of the return coil spring 28 is provided. The upstream end of the internal passage 44 of the adjusting pipe 42 communicates with a fuel supply passage (not shown) via the filter 40. Internal passage 4 of adjusting pipe 42
The downstream end of 4 is connected to the inner hole 18a of the armature 18, the outer periphery of the armature 18, and the inner hole 1 of the distance piece 12 through the spring chamber 46 inside the fixed iron core 25.
2 a and communicates with the valve seat portion 6 through a gap between the needle valve 8 and the wall surface of the guide hole 7 . When the needle valve 8 is in the open position, pressurized fuel from a fuel supply passage (not shown) is supplied to the filter 40, the internal passage 44, and the nozzle spring chamber 4.
6. The air is injected from the injection hole 5 into the intake pipe through the inner hole 18a, the inner hole 12a, the guide port 7, and the valve seat 6.

At the outer periphery of the electromagnetic coil 26, a housing 50 having a horseshoe-shaped cross section as shown in FIG. 3 is formed by bending a plate made of a magnetic material such as low carbon steel.
is fixed to the valve case 3 and the fixed iron core 25 by spot welding, as shown in FIG. The spot welds are, for example, positions indicated by numerals 52, 53, 54, and 55. Here, the spool 22 around which the electromagnetic coil 26 is wound is configured to extend leftward in FIG. . The housing 50 has a slit portion 50a formed in the axial direction by bending a plate material made of low carbon steel, for example, and is discontinuous or non-conductive in the circumferential direction, so that eddy currents are generated in the circumferential direction when the electromagnetic coil 26 is energized. It has the effect of preventing the occurrence. As a result, even if the housing 50 is made of inexpensive low carbon steel, good responsiveness equivalent to that of electromagnetic stainless steel can be obtained. Of course, this housing 50 can also be made of electromagnetic stainless steel. When electromagnetic stainless steel is used, the response is improved, and in this case, the shape is simple, so it is easy to process.

[0011] In this embodiment, the distance piece 1
Although the lift amount of the needle valve 8 can be adjusted by adjusting the plate thickness of the needle valve 2, instead of this, after assembling each part and before spot welding the fixed iron core 25 of the housing 50, the fixed iron core 2
5 and the axial position of the housing 50, and the needle valve 8
The lift amount can be adjusted. That is, during assembly, the fixed iron core 25 and the armature 18 are brought into contact with each other, and from this contact position, the fixed iron core 25 is moved upward from the armature 18 by the lift amount of the needle valve 8 and the air gap amount, and then the housing 50 The air gap can be adjusted by spot welding to the fixed iron core 25.

An electromagnetic fuel injection valve according to a second embodiment of the present invention is shown in FIGS. 4 and 5. In this second embodiment, the connection between the housing 60, the fixed iron core 25, and the valve case 3 is fixed by caulking. Specifically, housing 6
The upper end 60a of the housing 60 is caulked and fixed to the fixed iron core flange part 25a, and the lower end 60b of the housing 60 is caulked and fixed to the valve case flange part 3a. In this embodiment, as shown in FIG. 5, the housing 60 has slit portions 60c, 60c that are discontinuous in the circumferential direction, so generation of eddy current in the circumferential direction is suppressed, and responsiveness of valve opening and closing is improved. is good. Note that the cutout portion 60d is for drawing out the conductor of the electromagnetic coil 26. The other constituent parts are the same as those in the first embodiment, so substantially the same constituent parts are given the same reference numerals and the explanation thereof will be omitted.

FIG. 6 shows an electromagnetic fuel injection valve according to a third embodiment of the present invention. In the third embodiment, the upper end 3a of the valve case 3
In this example, the lower end 66a of the pipe 66 is fixed by brazing, and a single O-ring 68 provided between the fixed iron core 25 and the pipe 66 performs fuel sealing. Since the number of O-rings is reduced, there is an effect that the number of man-hours required for assembling the injection valve is reduced. Not only can corrosion resistance and responsiveness be improved, but processability is also easy. Since the other parts are the same as those in the first embodiment, components that are substantially the same as those in the first embodiment are denoted by the same reference numerals, and explanations thereof will be omitted.

[0014]

As explained above, according to the electromagnetic fuel injection valve of the present invention, since the housing that houses the electromagnetic coil is formed with slits that are discontinuously non-conductive in the circumferential direction, The housing can be easily formed by bending the plate material, and since eddy currents are less likely to occur, responsiveness can be improved. In addition, corrosion resistance is ensured in the parts that come into contact with fuel. Therefore, corrosion resistance and responsiveness are improved, manufacturing costs such as material costs are reduced, and assembly is facilitated.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an electromagnetic fuel injection valve according to a first embodiment of the present invention.

FIG. 2 is a side view showing an electromagnetic fuel injection valve according to a first embodiment of the present invention.

FIG. 3 is a perspective view showing a valve case used in the first embodiment of the present invention.

FIG. 4 is a sectional view showing a fuel injection valve according to a second embodiment of the present invention.

FIG. 5 is a perspective view showing a valve case used in a second embodiment of the present invention.

FIG. 6 is a sectional view showing an electromagnetic fuel injection valve according to a third embodiment of the present invention.

[Explanation of symbols]

1 Electromagnetic fuel injection valve 2 Valve body 5 Injection hole 6 Valve seat 7 Guide hole 8 Needle valve (valve member) 18 Armature 25 Fixed iron core 26 Electromagnetic coil 28 Returning coil spring (biasing means) 50
Housing 50a slit part

Claims (1)

[Claims] 1. A valve body having a reciprocating valve member, a guide hole that guides the valve member so as to be movable in an axial direction, a valve seat portion that the valve member can come into contact with, and an injection hole; A biasing device that biases a valve member in a valve closing direction, an electromagnetic coil that moves the valve member in a valve opening direction by electromagnetic attraction force against the biasing device, and a cylindrical housing that houses the electromagnetic coil. An electromagnetic fuel injection valve comprising: a housing formed by bending a plate material into a cylindrical shape and having a slit in the circumferential direction so as to be non-conductive.