JP2002295329A - Electromagnetic fuel injection valve and fuel injection device - Google Patents

Abstract

(57) [Problem] To expand the dynamic range of injection quantity characteristics by enabling high-speed movement of a valve body and at the same time securing a high suction force. An electromagnetic fuel injection valve for injecting fuel from a fuel injection hole (2) by driving a valve body (4) provided to be able to contact and separate from a valve seat (3) by electromagnetic force, wherein the electromagnetic force is generated. A coil 15, a fixed iron core 9 fixed to the coil side, and a movable iron core 5 driven together with the valve element.
In an electromagnetic fuel injection valve provided such that the fixed iron core and the movable iron core have opposing surfaces, at least one of the opposing surfaces provided on the fixed iron core and the movable iron core has a tapered portion. , Provided at least one surface at intervals in the circumferential direction around the valve axis,
Further, a concave portion communicating with the fuel passage communicating with the fuel injection hole is formed.

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 and a fuel injection device mounted on an internal combustion engine for controlling a fuel supply amount.

[0002]

2. Description of the Related Art An electromagnetic fuel injection valve (hereinafter referred to as a fuel injection valve) is axially slidable at a fuel injection hole, a valve seat disposed in the vicinity thereof, and a position facing the valve seat. And a spring supported by the valve body. The spring generates a force that presses the valve body toward the valve seat.

In a state where the valve seat and the valve body are in contact with each other by a spring force (hereinafter, referred to as a valve closing position), the fuel passage is closed, so that no fuel is injected from the fuel injection hole. When the valve element slides in the axial direction and moves away from the valve seat (hereinafter referred to as a valve open position) by a driving means utilizing electromagnetic force or the like generated by energizing the coil,
Since the fuel passage is opened, fuel is injected from the fuel injection hole. Here, by cutting off the current to the coil,
If the force for holding the valve body at the valve opening position is removed, the valve seat comes into contact with the valve body again due to the spring force, and the fuel injection stops.

[0004] As described above, in the fuel injection valve, the position of the valve body is switched to adjust the time during which fuel injection is maintained, thereby controlling the fuel supply amount.

Time), or the time from when the power supply to the coil is cut off to when the movement of the valve body from the open position to the closed position is completed (hereinafter referred to as a valve closing delay time) is short.
That is, high speed driving of the valve element is required.

As a conventional technique for driving a valve at high speed, there is Japanese Patent Application Laid-Open No. 2000-265919. The end surface of a fixed core called a core is a flat surface, and an annular flat surface portion having a small width and a gentle taper portion are formed on an end surface of a movable core called an armature.

[0007]

In the above prior art, the valve body is driven at a high speed by smoothing the fuel flow between the fixed core and the movable core during the movement of the movable core.

However, in the above-mentioned prior art, sufficient consideration has not been given to reducing the response delay of the electromagnetic force due to the eddy current generated in the fixed iron core and the movable iron core. Had limitations. In addition, since the magnetic resistance increases in the tapered portion, there is a problem that the attraction force decreases.

An object of the present invention is to solve the above problems, suppress eddy currents generated in a fixed iron core and a movable iron core, reduce a delay in response to an electromagnetic force, and at the same time secure a high suction force to secure a valve body. It is intended to drive at a higher speed.

[0010]

In order to achieve the above object, according to the present invention, at least one of opposing surfaces provided on a fixed iron core and a movable iron core of an electromagnetic fuel injection valve is provided. And a recess formed in the circumferential direction around the valve axis and communicating with a fuel passage communicating with the fuel injection hole.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. << Overview of FIG. 1 FIG. 2 Movable Iron Groove >> FIG. 1 shows an embodiment of the fuel injection valve of the present invention.

An orifice plate 19 fixed to the nozzle 1 is provided with a fuel injection hole 2 and a valve seat 3. Valve body 4
Is connected to the movable iron core 5, the cylindrical member 6, and the tip member 7, and is supported so as to be slidable in the axial direction of the tip member 7. A substantially disk-shaped spring member 8 is provided between the upper end of the tubular member 6 and the movable core 5. The valve body 4 has its tip and the valve seat 3
Can be slid in a range from a valve-closed position at which the movable core 5 contacts with the movable iron core 5 to an valve-opened position at which the inner fixed iron core 9 contacts. Fuel is supplied from a fuel supply port 10, passes through a filter 16, passes through a spring adjuster 11 and a spring 1.
2. The swirling force is given by the swirler 18 through the fuel holes 17 provided in the tubular member 6, passing through the inside of each of the additional mass 13 and the spring member 8, and guided to the fuel injection holes 2.

A spring adjuster 11 is fixed below the filter 16. The spring 12 is provided in a compressed state with the lower end of the spring adjuster 11 as a fixed end. An additional mass 13 slidable in the axial direction is provided between the spring 12 and the spring member 8. The spring force is transmitted to the valve body 4 via the additional mass 13 and the spring member 8, and the valve body 4 is pressed against the valve seat 3 and is held at the valve closing position. In this state, since the fuel passage is closed, fuel injection from the fuel injection holes 2 is not performed.

A coil 15 is provided in a space surrounded by the inner fixed core 9 and the outer fixed core 14. When a current is applied to the coil 15, a magnetic circuit is formed in which the inner fixed iron core 9, the movable iron core 5, the portion near the outer periphery of the movable iron core 5 of the nozzle 1, and the outer fixed iron core 14 make a circuit, and the movable iron core 5 passes through the inner fixed iron core 9. The valve body 4 is attracted by the electromagnetic force and moves to the valve opening position.
In this state, a gap is formed between the valve body 4 and the valve seat 3, so that the fuel passage is opened and fuel is injected from the fuel injection hole 2. When the energization of the coil 15 is stopped, the electromagnetic force is extinguished, so that the valve body 4 is again moved to the valve closing position by the spring force, and the fuel injection from the fuel injection hole 2 is stopped.

The material of the inner fixed iron core 9, the movable iron core 5, and the outer fixed iron core 14 is preferably stainless steel having magnetism, but is not limited thereto, and any magnetic material may be used.

The function of the fuel injection valve is as described above.
By switching the position of the valve body 4, the duration of fuel injection is adjusted to control the fuel supply amount.

In order to improve the fuel efficiency characteristics of an internal combustion engine,
It is necessary to precisely control the fuel supply amount, and a fuel injection valve capable of reducing the minimum value of the fuel injection amount that can be set by one injection operation (hereinafter referred to as the minimum injection amount) is required. For this purpose, high-speed driving of the valve element 4 is important. The time from when the energization of the coil 15 is started to when the movement of the valve element 4 from the valve closing position to the valve opening position is completed is referred to as a valve opening delay time. Further, the time from when the energization of the coil is cut off to when the movement of the valve element 4 from the valve opening position to the valve closing position is completed is referred to as a valve closing delay time. It is necessary to reduce the valve opening delay time and the valve closing delay time in order to reduce the minimum injection amount.

Therefore, in the present embodiment, a movable core groove 20 is provided on the upper end surface of the movable core 5.

Here, the present embodiment will be described in detail with reference to FIG. FIG. 2 is an enlarged view of the movable iron core 5 shown in FIG. The upper diagram in FIG. 2 is a cross-sectional view of a surface near the upper end surface of the movable core 5 and perpendicular to the central axis of the movable core 5. The lower part of FIG.
It is sectional drawing about the -B 'plane. In the figure below, for the sake of explanation, a part of each of the inner fixed iron core 9, the additional mass 13, and the nozzle 1 is also shown.

On the suction surface of the movable core 5, a linear movable core groove 20 having a narrow width is formed. The width of the movable core groove 20 is 1
mm or less, preferably 0.5 mm or less, if possible, but is not limited to these values. Note that the suction surface of the movable core 5, that is, the surface facing the fixed core 9 may be an annular surface centered on the valve axis and substantially perpendicular to the valve axis.

Further, for example, four movable core grooves 20 are provided radially at symmetrical positions on a plane including the central axis. Further, the movable core groove 20 communicates with an axial inner fuel passage 21 which is formed in a gap between the inner periphery of the movable core 5 and the outer periphery of the additional mass 13. In addition, the movable core groove 20 communicates with an axially outer fuel passage 22 formed in a gap between the outer periphery of the movable core 5 and the inner periphery of the nozzle 1.

Here, in the vicinity of the center between the inner circumference and the outer circumference of the suction surface of the movable iron core 5, a circular closed circular curve centered on the center axis of the movable iron core 5 is considered. When the circumferential closed curve is traced in the circumferential direction, the suction portion 50 sucked by the inner fixed iron core 9 and the movable core groove 20 are alternately formed. Further, the sum of the lengths of the circumferential closed curves on the suction portion 50 is at least three times, preferably 5 times or more the total length of the circumferential closed curves on the movable core groove 20.
More than double.

As described above, the electromagnetic fuel injection valve of the embodiment is configured to inject fuel from the fuel injection hole 2 by driving the valve body 4 provided to be able to contact and separate from the valve seat 3 by electromagnetic force. In the fuel injection valve, a means for generating an electromagnetic force includes a coil 15, a fixed core 9 fixed to the coil 15, and a movable core 5 driven together with the valve element. The iron core 5 is provided so as to have opposing surfaces. The movable iron core 5 is communicated with a fuel passage communicating with the fuel injection hole 2 on a surface facing the fixed iron core 9 at intervals in a circumferential direction about the valve axis (center axis of the valve element). A recess (groove) 20 is formed. The concave portion (groove portion) 20 may be formed such that at least one end on the inner peripheral side or the outer peripheral side communicates with the inner peripheral surface or the outer peripheral surface of the movable iron core 5. Alternatively, a flat portion and a concave portion (groove portion) 20 may be alternately provided on a surface facing the fixed core 9 provided on the movable core 5 in a circumferential direction around the valve axis. At this time, the recess 20 may be formed to extend radially around the valve axis. In order to increase the magnetic attraction force, it is preferable that the ratio of the area of the flat portion and the area of the concave portion (groove) 20 occupying the opposing surface is made larger in the flat portion. Further, the recess (groove) 20 may be provided on the surface of the fixed iron core 9 facing the movable iron core 5.

According to such a configuration, the following effects can be obtained. << Suppressing force and eddy current of fuel and keeping suction force large and expanding dynamic range >> When movable iron core 5 is sucked into inner fixed iron core 9, fuel sandwiched between both suction surfaces is It is easy to escape to the inner fuel passage 21 and the outer fuel passage 22 through the movable iron core groove 20. Therefore,
The resistance of the fuel acting on the movable core 5 can be reduced, and the movable core 5 moves at high speed, so that the valve opening delay time can be reduced.

When the movable iron core 5 is to be separated from the inner fixed iron core 9, fuel easily flows through the movable iron core groove 20 from the inner fuel passage 21 and the outer fuel passage 22 between the two suction surfaces. Therefore, it is possible to suppress the fuel between the suction surfaces from becoming a negative pressure. Therefore, the resistance of the fuel acting on the movable core 5 can be reduced, and the movable core 5 moves at high speed, so that the valve closing delay time can be reduced.

<< Synergistic effect of taper + slit >>
In this embodiment, the movable iron core groove 2 is provided on the suction surface of the movable iron core 5.
At the same time as providing 0, a taper portion 51 having an extremely shallow angle is provided. According to such a configuration, the following synergistic effects can be obtained.

When the movable core 5 is sucked into the inner fixed core 9, the fuel interposed between the two suction surfaces passes through the movable core groove 20 and the tapered portion 51, and passes through the inner fuel passage 21.
Easier to escape. Therefore, the resistance of the fuel acting on the movable core 5 can be reduced, and the movable core 5 moves at high speed, so that the valve opening delay time can be reduced. Here, the difference in effect from the case where only the tapered portion 51 is provided without providing the movable core groove 20 will be described in detail. In order to increase the magnetic attraction force, it is desirable to reduce the gap between the inner circumference of the nozzle 1 and the outer circumference of the movable iron core 5, so that the cross-sectional area of the outer fuel passage 22 must be reduced. Therefore,
When only the tapered portion is provided, of the fuel sandwiched between the suction surfaces, the fuel distributed near the outer peripheral portion of the movable iron core 5 is hardly discharged to the outside. Tapered portion 51 and movable core groove 20
Is provided at the same time, the fuel distributed in the vicinity of the outer peripheral portion passes through the movable core groove 20 extending to the outer peripheral portion, and through the tapered portion 51, spreads two-dimensionally on the suction surface through the inner fuel passage 21. Will be able to escape. Therefore, the effect of shortening the valve opening delay time is high.

When the movable iron core 5 is to be separated from the inner fixed iron core 9, the inner fuel passage 21 and the outer fuel passage 22 pass through the movable iron core groove 20 in the radial direction between the two suction surfaces. Further, the fuel easily flows two-dimensionally through the tapered portion 51, so that it is possible to suppress the fuel between the suction surfaces from becoming a negative pressure. Therefore,
The resistance of the fuel acting on the movable core 5 can be reduced, and the movable core 5 moves at high speed, so that the valve closing delay time can be reduced. Here, the difference in effect from the case where only the tapered portion 51 is provided without providing the movable core groove 20 will be described in detail. As described above, the cross-sectional area of the outer fuel passage 22 must be reduced. Therefore, when only the tapered portion is provided, the fuel does not flow smoothly into the vicinity of the outer peripheral portion between the suction surfaces. When the tapered portion 51 and the movable iron core groove 20 are provided at the same time, the two-dimensionally spread from the inner fuel passage 21 into the suction surface via the tapered portion 51,
Fuel flows into the outer peripheral portion between the suction surfaces through the movable iron core groove 20. Therefore, the effect of shortening the valve closing delay is high.

It should be noted that providing only the movable core groove 20 without providing the tapered portion 51 does not impair the effects of the present invention.

The surface on which the tapered portion is provided and the surface on which the groove is provided are not necessarily the same. For example, the groove may be provided on the suction surface of the movable core 5, and the tapered portion may be provided on the suction surface of the fixed core 9. Also, the groove is provided on the suction surface of the fixed iron core 9,
The tapered portion may be provided on the suction surface of the movable iron core 5. Also,
Grooves and tapers may be provided on both the suction surfaces of the movable core 5 and the fixed core 9.

Further, the electric resistance in the circumferential direction of the surface of the movable core 5 is increased by the movable iron core groove 20, so that the magnetic flux changes at the start of energization of the coil 15 or at the time of interrupting the current. Eddy current can be suppressed. Therefore, the responsiveness of the electromagnetic force acting on the movable iron core 5 is improved, and the valve opening delay time and the valve closing delay time can be further reduced.

As described above, since the valve opening delay time and the valve closing delay time can be reduced, a fuel injection valve having a small minimum injection amount can be obtained.

Here, it is desirable to set the depth of the movable core groove 20 as follows.

An eddy current is generated on the surface of the movable core 5 due to a change in magnetic flux at the start of energization of the coil 15 or at the time of interrupting the current. The eddy current is characterized in that it flows only through a very shallow part of the surface of the members constituting the magnetic circuit, such as the movable core 5 and the inner fixed core 9. Skin depth δ (m) in the range where eddy current flows
Is the angular frequency of the current ω (1 / s), the magnetic permeability of the movable iron core 5 is μ (T · m / A), and the electric conductivity is σ (1 / Ωm). Can be estimated. δ = (2 / (ωσμ)) ^0.5 (1) For example, when converted from the change time of the current supplied to the coil 15 of the fuel injection valve, the angular frequency ω of the current change is approximately as follows. ^{3 × 10 4 · π <ω} <5 × 10 4 · π and (2), the electrical conductivity of the movable iron core 5 sigma is generally the extent described below. 1 × 10 ⁶ <σ <2 × 10 ⁶ (3) Further, the magnetic permeability μ of the movable iron core 5 is approximately as follows. 1 × 10 ⁻⁴ <μ <5 × 10 ⁻⁴ (4) By substituting the numerical values of equations (2) to (4) into equation (1), the skin depth δ (m) is approximately as follows. 0.1 × 10 ⁻³ <δ <0.5 × 10 ⁻³ (5) According to the equation (5), under the driving condition of the fuel injection valve, the eddy current flows from the surface of the magnetic circuit member to a depth of 0.1 ( mm) to 0.
It can be seen that the flow is concentrated in the range up to 5 (mm).
Therefore, the depth of the movable core groove 20 is 0.1 (mm) or more,
If it is preferably 0.5 (mm) or more, the effect of suppressing eddy current can be enhanced. The driving conditions and material characteristics of the fuel injection valve may be different from those shown in the equations (2) to (4), and in this case, the appropriate groove depth also changes.
However, the concept of setting the groove depth is the same. By substituting the driving conditions and material characteristics of the fuel injection valve to which the present invention is applied into Equation (1), the skin depth δ may be calculated, and the groove depth may be set to be larger than this.

In the present embodiment, since the circumferential width of the movable iron core groove 20 is smaller than the circumferential width of the suction portion 50, the influence on the suction area is small, and a large suction force can be secured. . For this reason, fuel injection can be performed in a high fuel pressure state, so that the maximum injection amount per unit time can be increased, and the dynamic range of the fuel injection amount characteristic can be expanded.

<< The tapered portion can be made shallow >> Further, in the present embodiment, since the tapered portion 51 and the movable iron core groove 20 are used together, the angle of the tapered portion can be made extremely small. Therefore, an increase in magnetic resistance due to the tapered portion 51 can be minimized, a large attractive force can be secured, and the dynamic range can be expanded.

<< Effect of (gap between core and additional mass) <(gap between anchor and additional mass) >> When the valve body 4 moves from the valve opening position to the valve closing position and collides with the valve seat 3, the valve body 4 Rebounds due to repulsion. The behavior of re-injecting a small amount of fuel even after the valve is closed due to this rebound phenomenon will be referred to as secondary injection. Depending on the characteristics of the combustion, the effect of the secondary injection may hinder precise control of the fuel injection amount.

In this embodiment, the additional mass 13 and the spring member 8 are provided to prevent the secondary injection. The outer peripheral portion of the spring member 8 is supported by the upper end surface of the tubular member 6. The tip of the additional mass 13 contacts the vicinity of the inner periphery of the spring member 8. The spring member 8 has a spring action by bending its inner peripheral portion in the valve axis direction. At the moment when the valve body 4 moves from the valve-opening position to the valve-closing position, collides with the valve seat 3 and tries to jump up, the additional mass 13 maintains the downward speed, and the valve body 4 Exerts a downward force on This prevents a rebound phenomenon and suppresses secondary injection.

In order to stabilize such a secondary injection prevention effect, it is necessary to ensure the coaxiality between the tip position of the additional mass 13 and the spring member 8 in order to stabilize the spring constant of the spring member. Furthermore, it is better to apply a certain amount of damping force to the additional mass 13 itself.

Therefore, in the present embodiment, the gap between the inner diameter of the fixed iron core 9 and the outer diameter of the additional mass 13 is reduced.
The gap with the outside diameter is increased.

According to such a configuration, the additional mass 13 is guided by the inner diameter of the fixed iron core 9, and the displacement of the distal end can be prevented. Furthermore, additional mass 13 and fixed iron core 9
Because of the small gap between the fuel and the fuel,
A damping force can be applied to the additional mass 13. Therefore, the secondary injection suppression effect can be stabilized. Furthermore, since the gap between the inner diameter of the movable core 5 and the outer diameter of the additional mass 13 is relatively large, the cross-sectional area of the inner fuel passage 21 can be increased. Therefore, it is possible to smoothly flow the fuel between the suction surfaces and the flow of the fuel between the suction surfaces via the inner fuel passage 21. Therefore, it is possible to achieve both the suppression of the secondary injection and the reduction of the valve opening delay and the valve closing delay, so that it is possible to precisely control the fuel injection amount.

As shown in FIG. 3, the inner diameter of the fixed iron core 9 and
Even if the inner diameter of the movable core 5 is made equal and the tip of the additional mass 13 is made smaller, the same effect as above can be obtained.

Further, as shown in FIG.
May be provided with a horizontal hole 52 so that the inflow and outflow of fuel from the suction surface can be performed smoothly.

FIG. 1 shows a fuel injection valve of a type in which the movable iron core 5 and the inner fixed iron core 9 come into direct contact with each other at the valve opening position. In the fuel injection valve of this type, the thickness of the fuel film sandwiched between the suction surfaces of the movable iron core 5 and the inner fixed iron core 9 at the valve opening position is extremely small. Since the pressure of the fuel film is inversely proportional to the cube of the thickness, the pressure of the fuel film generated due to the movement of the movable core 5 becomes very large. Therefore, the effect of the present invention is particularly great for the above-described type of fuel injection valve.

<< Since the groove communicates on both sides, the resistance is smaller than that of the one-sided communication. >> Here, the movable iron core groove 20 communicates with the inner fuel passage 21 and the outer fuel passage 22. As a result, the fuel distributed between the suction surfaces along with the movement of the movable iron core 5 can escape toward the closer one of the two fuel passages or flow from the closer one. Therefore, since the movement distance of the fuel is short, the movement of the fuel is fast,
The resistance acting on the movable core 5 can be further reduced as compared with the case where the movable core groove 20 communicates with only one of the inner peripheral side and the outer peripheral side.

<< Since the groove crosses the circumferential closed curve near the center of the inner and outer diameters, a short path can be made. >> As described above,
In the vicinity of the center between the inner circumference and the outer circumference of the suction surface of the movable iron core 5,
Virtually, consider a circular circumferential closed curve centered on the central axis of the movable iron core 5. The movable iron core groove 20 is provided so as to cross this circumferential closed curve.

When the movable iron core 5 is attracted to the inner fixed iron core 9, the fuel pressure becomes highest near this circumferential closed curve. On the other hand, the pressure in the movable iron core groove 20 is maintained at a pressure as low as that of the inner fuel passage 21 and the outer fuel passage 22 communicating with each other. The fact that the movable core groove 20 crosses the above-mentioned circumferential closed curve can shorten the distance between the highest pressure portion on the closed curve and the low-pressure portion in the movable core groove 20. Therefore, the fuel easily flows from the high-pressure section to the low-pressure section, and the resistance acting on the movable core 5 can be further reduced.

On the other hand, when the movable core 5 moves away from the inner fixed core 9, the fuel pressure becomes the lowest in the vicinity of this circumferential closed curve. On the other hand, the pressure in the movable core groove 20 is controlled by the inner fuel passage 21 and the
The pressure is maintained at a relatively high pressure, which is about the same as that of the pressure. The fact that the movable core groove 20 crosses the above-mentioned circumferential closed curve means that the lowest pressure on the closed curve and the movable core groove 20
The high pressure section inside can shorten the distance. Therefore, the fuel easily flows from the high-pressure section to the low-pressure section, and the resistance acting on the movable core 5 can be further reduced.

<< Since the grooves are symmetrical, there is no eccentricity of the resistance,
Uneven Wear Prevention> Further, since the movable core groove 20 is provided at a symmetrical position with respect to a plane including the central axis, the fuel flow accompanying the movement of the movable core 5 is also symmetrical, and the resistance acts in the axial direction. No eccentricity. Therefore, uneven wear of the sliding portion such as the outer peripheral portion of the movable iron core 5 can be prevented.

<< Ensuring Radial Rigidity >>
Is provided only on the surface of the movable core 5 and does not penetrate in the axial direction of the movable core 5. Therefore, the radial rigidity of the movable iron core 5 can be secured, and the variation in the inner diameter and the outer diameter is small, so that the gap between the inner circumference and the additional mass 13 and the gap between the outer circumference and the nozzle 1 can be appropriately maintained. .

It is desirable that the movable iron core groove 20 communicates with both the axial fuel passage on the inner peripheral side and the outer peripheral side. The effect of is obtained.

The movable core groove 20 is preferably provided symmetrically with respect to a plane including the central axis, but may not be symmetrical if the eccentricity of the resistance does not matter.

Further, the movable iron core groove 20 does not necessarily have to be provided radially, and may have any shape as long as it serves as a flow path for fuel between the suction surfaces in the inner circumferential direction or the outer circumferential direction.

Further, the movable iron core groove 20 is not necessarily required to be linear, but may be provided in a curved shape.

Further, the number of the movable iron core grooves 20 is not limited to four, but may be any number as long as the resistance and eddy current of the fuel can be suppressed.

Further, the effect of the present invention can be obtained by providing a similar groove on the suction surface of the inner fixed iron core 9 without providing the movable core groove 20. It is needless to say that the same effect can be obtained by providing a similar groove on the suction surface of the inner fixed core 9 in addition to the movable core groove 20.

Further, in order to enhance the effect of suppressing the eddy current, a groove may be provided on at least one of the side surfaces of the movable core 5 and the fixed core 9.

Further, in FIG. 1, the case where the movable range of the movable iron core 5 on the valve opening side is determined by the contact between the upper end surface of the movable iron core 5 and the lower end surface of the fixed iron core 9 has been described. The present invention is also effective for a fuel injection valve of a different type, such as a fuel injection valve having a stopper member for determining a movable range by contacting a valve body at an open position.

Further, the sectional shape of the movable core groove 20 on a plane perpendicular to the longitudinal direction may be, for example, a substantially rectangular shape, a substantially inverted triangular shape, or a bottom portion having an arc shape. It is not limited to. Any cross-sectional shape may be used as long as it becomes a fuel flow path and eddy current can be suppressed.

Further, in order to increase the cross-sectional area of the outer fuel passage 22 and further improve the fuel flow, a position corresponding to the end of the movable iron core groove 20 on the outer peripheral portion of the movable iron core 5 is formed into a planar shape. Thus, the gap with the inner periphery of the nozzle 1 may be enlarged.

Further, the suction surface of the movable iron core 5, that is, the surface facing the fixed iron core 9 may be an annular surface centered on the valve axis and substantially perpendicular to the valve axis.

FIG. 5 Example of Groove Formation by Surface Adhesion Layer FIG. 5 is an enlarged sectional view of the movable core 5 in order to represent another embodiment of the present invention. The upper part of FIG. 5 is a cross-sectional view of a plane near the upper end face of the movable core 5 and perpendicular to the central axis of the movable core 5. The lower diagram in FIG. 5 shows B- shown in the upper diagram.
It is sectional drawing about B 'surface.

A surface layer 23 harder than the base material of the movable core 5 is provided on the suction surface of the movable core 5, and a movable core groove 20 is formed except for a portion where the surface layer is not provided linearly. As the surface layer, a chromium plating layer, a nitride layer, a quenched layer, and the like are suitable, but not limited thereto. According to the above, since the grooves are formed by the surface layer, there is no increase in costs such as cutting and plastic working. Since there is no processing cost such as cutting and plastic working, the movable core groove 20 can be formed at low cost. . Since the groove is formed by the surface layer, the groove width can be reduced. In addition, according to the above method, since the cutting tool or the plastic processing tool is not used, the size of the movable iron core groove 20 is not restricted by the size of the tool. The width and depth can be set. By the above method, for example, 0.5 mm or less, preferably 0.1 mm or less.
If a narrow groove width of 3 mm or less is set, a larger suction force can be secured. Since the grooves are formed by the surface layer, there is no increase in magnetic resistance. In addition, usually, the surface layer is often required to prevent abrasion of the suction surface due to collision and to improve the response of the electromagnetic force.
According to the present embodiment, the magnetic resistance can be reduced without providing the surface layer 23 for the purpose of forming the groove. Therefore, a large suction force can be secured.

The groove may be formed by providing a relatively thin portion of the surface layer.

The same effect can be obtained even if a groove is formed by chemically removing a part of the surface by etching or the like.

The effect can also be obtained by providing a groove on the suction surface of the inner movable iron core 9 in the same manner.

<< FIG. 6 Example of Groove Not Communicating with Inner Diameter >> FIG.
FIG. 4 is a cross-sectional view of a movable core 5 taken out and enlarged to represent another embodiment of the present invention. The upper part of FIG. 6 is a cross-sectional view of a plane near the upper end surface of the movable core 5 and perpendicular to the central axis of the movable core 5. The lower part of FIG. 6 shows DD ′ shown in the upper part.
It is sectional drawing about a surface.

The movable iron core groove 20 is prevented from communicating with the inner diameter side of the movable iron core 5.

According to this, when the movable core groove 20 is plastically worked, it is possible to prevent the swelling occurring on the inner peripheral side of the movable core 5. When the bulge occurs on the inner peripheral side, the additional mass 13 and, in some cases, inclusions such as springs may interfere with the inner periphery of the movable iron core 5. To avoid this, it is necessary to finish the inner circumference.
According to the present embodiment, since swelling can be prevented, interference with inclusions can be avoided without adding a step of finishing the inner periphery.

Since the outer peripheral portion of the movable iron core 5 is slid and guided by the inner periphery of the nozzle 1, a finishing step is required regardless of whether or not the bulge is caused by plastic working. Therefore, it is preferable to make the movable iron core groove 20 communicate with the outer peripheral side so that the fuel between the suction surfaces can easily flow.

A circular circumferential closed curve centered on the central axis of the movable core 5 is virtually considered near the center between the inner periphery and the outer periphery of the suction surface of the movable core 5. Also in the case of the present embodiment, for the same reason as described above, it is preferable that the movable core groove 20 is provided so as to cross this circumferential closed curve.

Needless to say, the movable iron core groove 20 shown in FIG. 6 may be provided by a method other than plastic working.

The same effect can be obtained when a similar groove is provided in the inner fixed iron core 9.

<FIG. 7 Chamfer + Groove> FIG. 7 is a cross-sectional view of the movable iron core 5 taken out and enlarged to show another embodiment of the present invention. The upper part of FIG. 7 is a cross-sectional view of a plane perpendicular to the central axis of the movable core 5 near the upper end surface of the movable core 5. 7 is a cross-sectional view of the EE ′ plane shown in the upper figure.

The inner peripheral portion of the suction surface of the movable iron core 5 is provided with a chamfer 24 which is larger than the outer peripheral side. Movable iron core groove 2
0 is set so as to communicate with the chamfered portion 24 and not with the outer peripheral side. As the manufacturing method, first, it is preferable to provide the movable core groove 20 that does not communicate with any of the inner periphery and the outer periphery, and second, it is preferable to provide the chamfered portion 24 that communicates with the movable core groove 20. It is not limited to this.

According to such a configuration, the movable core groove 20
Does not bulge on the inner and outer circumferences of the movable iron core 5 when plastic working is performed. Therefore, the size of the gap between the inner periphery of the movable core 5 and the outer periphery of the additional mass 13 and the size of the gap between the outer periphery of the movable core 5 and the inner periphery of the nozzle 1 can be appropriately maintained. Furthermore, the movable core groove 20 communicates with the inner fuel passage via the chamfered portion 24, and the resistance acting on the movable core 5 is reduced.

The movable iron core groove 20 shown in FIG. 7 may be provided by a method other than plastic working.

The chamfered portion 24 may be rounded.

Further, the same effect can be obtained when a similar groove is provided in the inner fixed iron core 9.

FIG. 8 Grooves Communicating with Vertical Holes FIG. 8 is an enlarged sectional view of the movable iron core 5 in order to represent another embodiment of the present invention. The upper diagram in FIG. 8 is a cross-sectional view of a surface near the upper end surface of the movable core 5 and perpendicular to the central axis of the movable core 5. The lower part of FIG. 8 is a cross-sectional view of the FF ′ plane shown in the upper part.

The movable iron core 5 has a movable fuel hole 25 in the axial direction.
And the movable iron core groove 20 is provided so as to communicate with the movable fuel hole 25.

According to such a configuration, the fuel between the suction surfaces can move using the movable iron core groove 20 and the movable fuel hole 25 as passages. Since the movable fuel hole 25 can secure a large flow path cross-sectional area, the fuel between the suction surfaces can be more easily flown.

Here, a circle centered on the center axis of the movable core 5 and a center passing through the centers of the plurality of movable fuel holes 25 and the outer periphery of the movable core 5 are formed around the center axis of the movable core 5. Consider the closed curve of. It is important that the movable core groove 20 be provided so as to cross this closed curve. As described above, by reducing the distance between the high pressure section and the low pressure section,
This is because the fuel easily flows and the resistance acting on the movable iron core 5 can be further reduced.

The number of the movable holes 25 is not limited to four. For example, the range of 1 to 8 is suitable, but may be more.

Further, it is needless to say that the same effect can be obtained even when similar holes and grooves are provided on the suction surface of the inner fixed iron core 9.

<< FIG. 9 Movable Core Groove + Fixed Core Taper >> FIG. 9 is an enlarged sectional view of the movable core 5 and the inner fixed core 9 in order to represent another embodiment of the present invention.

The movable iron core groove 20 is not directly connected to the inner peripheral side of the movable iron core 5. A fixed chamfer 26 is provided on the inner periphery of the suction surface of the inner fixed iron core 9. Fixed chamfer 26
Is located on the outer diameter side than the inner end of the movable iron core groove 20.

According to such a configuration, the movable core groove 20
In order to prevent the inner diameter of the movable core 5 from expanding due to plastic working of the movable core 5, even when the movable core groove 20 is not directly communicated with the inner peripheral side, the fixed chamfered portion 26 is formed from the movable core groove 20 as a flow path. Through this, the inside of the movable iron core 5 is communicated with, so that the fuel between the suction surfaces can easily flow.

The movable core groove 20 may be provided by a method other than plastic working.

The fixed chamfer 26 may be rounded.

Further, the effect can be obtained when a groove is formed in the inner fixed iron core 9 that does not directly communicate with the inner diameter, and a similar chamfer is provided in the inner diameter of the movable iron core 5.

In order to suppress an increase in manufacturing cost, it is not necessary to provide the fixed chamfered portion 26 on the suction surface of the inner fixed iron core 9 and provide a groove on the suction surface of the movable iron core 5. For forming the inner fixed iron core 9, plastic working such as press or forging can be used. According to the plastic working, since the fixed chamfered portion 26 can be formed at the same time, the cost is low.

<< FIG. 10 Radial Groove + Circular Groove >> FIG.
FIG. 4 is a cross-sectional view of a movable core 5 taken out and enlarged to represent another embodiment of the present invention. The lower part of FIG. 10 is a cross-sectional view of the movable core 5 on a plane including the central axis of the movable core 5. The upper part of FIG. 10 is a cross-sectional view of the plane AA ′ shown in the lower part.

The suction surface of the movable core 5 is provided with a movable core groove 20.
In addition, an annular groove 27 is provided.

According to this, since the suction surface of the movable iron core 5 is finely divided, the distance from any point on the suction surface to the movable iron core groove 20 and the annular groove 27 can be reduced, and the fuel between the suction surfaces can be reduced. Can be made to flow more easily.

The position of the annular groove 27 is where the pressure difference between the inner and outer circumferential fuel passages of the movable iron core 5 and the axial fuel passage is greatest when no annular groove is provided. By providing an annular groove 27 that actively communicates with the movable iron core groove 20 at the portion where the pressure difference becomes the largest, the fuel between the suction surfaces can flow more easily.

Note that the same effect can be obtained when the same groove is provided on the suction surface of the fixed iron core 9.

<< FIG. 11 Split Anchor >> FIG. 11 is an exploded perspective view of the movable cores 5a, 5b and the tubular member 6 taken out and enlarged to show another embodiment of the present invention, and an assembled state thereof. It is a front view.

The movable iron cores 5a and 5b divided into two parts are
It is joined to the tubular member 6 by a method such as welding. The front view after joining is shown in the lower side of FIG. The arcs on the inner circumference of the suction surfaces of the movable iron cores 5a and 5b are each arcs smaller than 180 degrees. For example, 175 degrees or 178 degrees can be selected, but the present invention is not limited to this.

According to such a configuration, the movable iron core 5a,
By simply joining 5b to the tubular member 6, a linear groove is formed between them. Therefore, a step for processing the groove can be omitted. Further, since the circumferential passage of the eddy current of the movable iron core 5 can be completely cut off, the effect of suppressing the eddy current is extremely high, and the responsiveness of the electromagnetic force can be further enhanced.

<< FIG. 12 Deep Slit in Core >> FIG.
Is an inner fixed iron core 9 to represent another embodiment of the present invention.
It is sectional drawing which took out and expanded. 12 is a cross-sectional view of a surface of the inner fixed iron core 9 perpendicular to the central axis near the suction surface. The upper diagram in FIG. 12 shows AA ′ shown in the lower diagram.
It is sectional drawing about a surface. The upper part of FIG. 12 shows a part of the nozzle 1 in addition to the inner fixed iron core 9 for the sake of explanation.

The inner fixed iron core 9 is inserted into the inner diameter side of the nozzle 1 and is fixed to the nozzle 1 by a welded portion 28. The welding portion 28 has a function of preventing the fuel in the nozzle 1 from being discharged to the outside, that is, a welding having a sealing function.

According to such a configuration, the nozzle 1 can perform the sealing function in a portion below the welded portion 28, and the inner fixed iron core 9 can perform the sealing function in the portion above the welded portion 28. For this reason, in the portion below the welded portion 28, the inner fixed iron core 9 that does not require a sealing function is provided.
Can be provided with a deep fixed iron core groove 29. Depending on the position of the welded portion 28, the fixed iron core groove depth 29 can be set to a depth of about １ ／ to の of the entire axial length of the inner fixed iron core 9, but is limited to this range. It does not do. Since it is possible to increase the electric resistance in the circumferential direction of the fixed core 9 in a wide range in the axial direction having the fixed core groove 29, the eddy current generated due to the change in magnetic flux is further suppressed, and the electromagnetic force is reduced. Can be further improved.

<< FIG. 13 Step to Core >> FIG. 13 is an enlarged sectional view of the inner fixed core 9 taken out to show another embodiment of the present invention.

A step 30 is provided at the lower end of the fixed iron core 9. The height of the step is preferably about 10 μm, but is not limited to this.

According to this, since the flow path is formed by the step 30, the fuel between the suction surfaces can easily flow. In addition, when a polishing process is provided for finishing the lower end portion of the fixed iron core 9, if a step portion is formed on the grindstone,
Since the step portion 30 can be formed in accordance with this, it is not necessary to add a step for forming the flow path.

Needless to say, an effect can be obtained even if a similar step is provided on the suction surface of the movable iron core 5.

The step may be provided by a method other than polishing.

<< FIG. 14 Core End Surface R >> FIG. 14 is an enlarged sectional view of the inner fixed iron core 9 to show another embodiment of the present invention.

An R portion 31 is provided at the lower end of the fixed iron core 9.
The radius of curvature of the R portion is preferably about 10 mm to 200 mm, but is not limited thereto.

According to this, the flow path is formed by the slight gap between the R portion 31 and the movable iron core 5, so that the fuel can easily flow between the suction surfaces. Further, when a polishing process is provided for finishing the lower end portion of the fixed iron core 9, if an R portion is formed on the grindstone, the R portion 31 can be formed in accordance with the R portion, so that the flow path formation is performed. No additional process is required.

It is needless to say that an effect can be obtained even if the same R portion is provided on the suction surface of the movable iron core 5.

Further, the R portion may be provided by a method other than polishing.

<< FIG. 15 Turbo DI Engine >> FIG.
Represents an embodiment of the internal combustion engine of the present invention. here,
An internal combustion engine in which fuel is directly injected into a cylinder will be described, but the invention is not limited to this.

The operation of the internal combustion engine at light load will be described.

By opening the intake valve 32 and moving the piston 33 from top dead center to bottom dead center, air having a pressure approximately equal to the atmospheric pressure is introduced into the cylinder 35 from the intake pipe 34.

The fuel is supplied to the fuel injection valve 36 from a fuel supply system including a fuel tank and a fuel pump (not shown). Also, a command signal corresponding to the required fuel is sent from the engine control unit to the fuel injection valve drive circuit, and the coil of the fuel injection valve 36 is energized. In the process of compressing air with the movement of the piston 34 from the bottom dead center to the top dead center, the fuel injection valve 36 of the present invention is used to inject a very small amount of fuel according to a light load. The fuel is distributed around the spark plug by a method such as devising the shape near the injection hole of the fuel injection valve 36 or utilizing the air flow in the cylinder 35, and the fuel is ignited by the spark plug 37.

Due to the combustion pressure of the fuel, the piston 33
It moves from the top dead center toward the bottom dead center, and a rotational force is applied to a crankshaft (not shown).

The piston 33 moves from the bottom dead center to the top dead center again. At this time, the gas in the cylinder is discharged to the exhaust pipe 39 by opening the exhaust valve 38.

Since the internal combustion engine 40 of the present invention can inject a very small amount of fuel with high accuracy by using the fuel injection valve 36 having a small minimum injection charge at the time of light load, and can realize ultra-lean combustion, the fuel consumption characteristics are improved. Are better.

Next, the operation of the internal combustion engine under a high load will be described.

By opening the intake valve 32, moving the piston 33 from the top dead center to the bottom dead center, and sending compressed air into the intake pipe 34 by the supercharger 41, air having a pressure higher than the atmospheric pressure is released. It is introduced into the cylinder 35. In this intake process, the fuel injection valve 36 injects a large amount of fuel according to a high load.

In the process in which the air is compressed as the piston moves from the bottom dead center to the top dead center, the fuel is spread evenly over the entire combustion chamber.
Ignite.

Due to the combustion pressure of the fuel, the piston 33
It moves from the top dead center toward the bottom dead center, and a rotational force is applied to a crankshaft (not shown).

The piston 33 moves from the bottom dead center to the top dead center again. At this time, the gas in the cylinder is discharged to the exhaust pipe 39 by opening the exhaust valve 38.

Here, the fuel injection amount per unit time when the fuel injection valve 36 is kept open will be referred to as a static injection rate.

Normally, when emphasis is placed on the fuel consumption characteristics at light load, the static injection rate is reduced. Therefore, at high load,
There was some limit to the amount of fuel that could be injected. Therefore, even if a large amount of air is introduced, it is difficult to supply an appropriate amount of fuel, and it is difficult to configure an internal combustion engine using the supercharger 41 and the like. However, in the present invention, since the fuel injection valve 36 having a small valve opening delay and a valve closing delay and a large suction force is used, the minimum injection amount can be reduced while the static injection rate is kept large. Therefore, the internal combustion engine can be configured by adding the supercharger 41. Therefore, excellent fuel economy characteristics at light load can be obtained, and at the same time, a large amount of fuel can be injected according to the amount of air compressed by the supercharger 41, so that high output can be achieved. .

Although FIG. 15 shows an example of an internal combustion engine using gasoline as a fuel, the effects of the present invention can be obtained for an internal combustion engine using another fuel. For example, it can be applied to a diesel engine.

Incidentally, the magnetic circuit as the driving means of the valve element 4 is not limited to the one shown in FIG. The effect of the present invention described with reference to FIGS. 1 to 15 can be obtained with any configuration as long as it is a magnetic circuit for driving the valve element 4.

In FIG. 1, the means for driving the valve element 4 in the axial direction uses an electromagnetic force. However, the use of another driving means does not impair the effects of the present invention. . For example, the effect of the present invention described with reference to FIGS. 1 to 15 can also be obtained when a means for driving the valve body 4 in the axial direction by creating a pressure difference above and below the valve body 4 using fuel pressure. Can be obtained.

Also, the effect of the present invention described with reference to FIGS. 1 to 13 can be obtained for a fuel injection valve of a type in which the axial movable range of the valve element 4 is determined by another stopper member. Nor.

[0132]

According to the present invention, the valve resistance and the eddy current acting on the movable iron core can be suppressed, and the valve can be moved at a high speed.
Fuel injection with a small minimum injection amount can be performed.
At the same time, since a high suction force can be secured, a large value can be set as the fuel injection amount per unit time, so that the dynamic range of the injection amount characteristic can be widened.
Further, by using such a fuel injection valve, an internal combustion engine having excellent fuel economy characteristics and high output can be configured.

[Brief description of the drawings]

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

FIG. 2 is a cross-sectional view and a vertical cross-sectional view of a movable core of the electromagnetic fuel injection valve of FIG.

FIG. 3 is a cross-sectional view and a vertical cross-sectional view showing another embodiment of a movable core portion.

FIG. 4 is a cross-sectional view and a vertical cross-sectional view showing another embodiment of a movable core portion.

5A and 5B are a cross-sectional view and a vertical cross-sectional view illustrating another embodiment of the movable core portion.

FIG. 6 is a cross-sectional view and a vertical cross-sectional view showing another embodiment of the movable core portion.

FIG. 7 is a longitudinal sectional view showing another embodiment of the movable core and the fixed core.

FIG. 8 is a cross-sectional view and a vertical cross-sectional view illustrating another embodiment of the movable core portion.

FIG. 9 is a cross-sectional view and a vertical cross-sectional view showing another embodiment of the movable core portion.

FIG. 10 is a cross-sectional view and a vertical cross-sectional view showing another embodiment of the movable core portion.

FIG. 11 is a view showing another embodiment of the movable core portion.

FIG. 12 is a longitudinal sectional view and a transverse sectional view showing another embodiment of the inner fixed core portion.

FIG. 13 is a longitudinal sectional view showing another embodiment of the inner fixed iron core.

FIG. 14 is a longitudinal sectional view illustrating another embodiment of the inner fixed core.

FIG. 15 is a schematic diagram illustrating an embodiment of an internal combustion engine of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nozzle, 2 ... Fuel injection hole, 3 ... Valve seat, 4 ... Valve element, 5
... Movable iron core, 6 ... Cylindrical member, 7 ... Tip member, 8 ... Spring member, 9 ... Inner fixed iron core, 10 ... Fuel supply port, 11 ... Spring adjuster, 12 ... Spring, 13 ... Additional mass, 14 ... Outside fixed Iron core, 15: coil, 16: filter, 17: fuel hole, 18: swirler, 19: orifice plate, 20: movable core groove, 21: inner fuel passage, 22
... Outer fuel passage, 23 ... Surface layer, 24 ... Chamfered part, 25
... movable fuel holes, 26 ... fixed chamfers, 27 ... annular grooves, 2
8 ... welded part, 29 ... fixed iron core groove, 30 ... stepped part, 31 ...
R part, 32 ... intake valve, 33 ... piston, 34 ... intake pipe,
35 ... cylinder, 36 ... fuel injection valve, 37 ... spark plug, 38 ... exhaust valve, 39 ... exhaust pipe, 40 ... internal combustion engine, 4
1 ... supercharger, 50 ... suction part, 51 ... taper part, 52 ... side hole.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16K 31/06 H01F 7/16 DR (72) Inventor Makoto Yamamon 502, Kandatecho, Tsuchiura-shi, Ibaraki Pref. Inside Hitachi Machinery Research Laboratory (72) Inventor Toru Ishikawa 2520 Ojitakaba, Hitachinaka City, Ibaraki Prefecture Inside Hitachi, Ltd.Automotive Equipment Group (72) Inventor Atsushi Sekine 2477 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi, Ltd. Within Car Engineering (72) Inventor Kiyotaka Ogura 2520 No. Odaiba, Hitachinaka-shi, Ibaraki Prefecture Within Hitachi, Ltd. Automotive Equipment Group (72) Inventor Kenji Hirako 502 Kandachicho, Tsuchiura-shi, Ibaraki Machinery, Hitachi Ltd. Inside the laboratory (72) Inventor Yuzo Kadokomu 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Inside the Machinery Research Laboratory (72) Inventor Takaomi Nishigakido 502, Kandachicho, Tsuchiura-shi, Ibaraki Pref. Inside the Machinery Research Laboratories, Ltd. 3G066 AA02 AA11 AB02 AD12 BA07 BA09 BA11 BA16 BA17 BA19 BA46 BA49 BA51 BA55 CC06U CC14 CC66 CD14 CD21 CD30 CE23 CE24 CE25 CE26 CE31 CE34 DB08 DB09 3H106 DA07 DA13 DA23 DB02 DB12 DB23 DB32 DC02 DD03 EE04 GA 5E048 AB01 AD02 CA04

Claims (7)

[Claims] An electromagnetic fuel injection valve for injecting fuel from a fuel injection hole by driving a valve body provided to be able to contact and separate from a valve seat by an electromagnetic force, wherein said means for generating said electromagnetic force is provided. , A coil, a fixed iron core fixed to the coil side, and a movable iron core driven together with the valve element, the electromagnetic fuel injection valve including the fixed iron core and the movable iron core each having an opposing surface. In at least one of the opposed surfaces provided on the fixed iron core and the movable iron core, the fuel injection holes are provided at intervals in a circumferential direction about a valve axis. An electromagnetic fuel injection valve, wherein a concave portion communicating with a fuel passage communicating with the fuel injection valve is formed. 2. The electromagnetic fuel injection valve according to claim 1, wherein a tapered portion is provided on at least one of the opposed surfaces provided on the fixed iron core and the movable iron core. Characteristic electromagnetic fuel injection valve. 3. The electromagnetic fuel injection valve according to claim 1, wherein at least one of the inner circumferential side and the outer circumferential side of the recess communicates with the inner circumferential surface or the outer circumferential surface of the movable core. An electromagnetic fuel injection valve characterized in that: 4. The electromagnetic fuel injection valve according to claim 1, wherein the recess is formed by a groove extending radially about a valve axis. 5. The electromagnetic fuel injection valve according to claim 4, wherein a plurality of said recesses are arranged at positions symmetrical with respect to a center axis of the valve body. 6. The electromagnetic fuel injection valve according to claim 1, wherein a fuel passage extending to the fuel injection hole is formed on an inner peripheral side or an outer peripheral side of the movable iron core, the end being connected to the concave portion. An electromagnetic fuel injection valve characterized in that: 7. An electromagnetic fuel injection valve for injecting fuel from a fuel injection hole by driving a valve body provided to be able to contact and separate from a valve seat by an electromagnetic force, and a drive for driving the electromagnetic fuel injection valve A fuel injection device comprising: a circuit; and an engine control unit for giving a command signal to the drive circuit, wherein a means for generating the electromagnetic force includes a coil, a fixed iron core fixed to the coil, and the valve. In a fuel injection device provided with a movable core driven together with a body such that the fixed core and the movable core each have opposing surfaces, among the opposed surfaces provided on the fixed core and the movable core, At least one of the opposing surfaces is spaced in the circumferential direction around the valve axis, and at least one end on the inner circumferential side or the outer circumferential side is on the inner circumferential side or the outer circumferential side of the movable iron core. A fuel injection device, wherein a concave portion communicating with a peripheral side is formed.