JP2009209693A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the lowering of the rigidity of a joining pipe having slits. <P>SOLUTION: This fuel injection valve comprises a body having a fuel flow passage and a fuel injection hole formed at the downstream end of the fuel flow passage, a movable body disposed in the fuel flow passage and opening/closing the fuel injection hole by sliding along the fuel flow passage, a biasing member for biasing the movable body to the downstream side of the fuel flow passage, and a magnet for moving the movable body to the upstream side of the fuel flow passage against the biasing force of the biasing member. The movable body comprises a valve element for closing the fuel injection valve, an armature positioned further on the upstream side than the valve element, and a tubular joining pipe for joining the valve element and the armature. The slits extending from the upstream end to the downstream end are formed in the joining pipe. A displacement portion extending while each slit circumferentially displaces relative to the axis of the joining pipe is formed in each slit. The extending displacement angle of the slit at the displacement portion is in excess of 45°. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel injection valve that injects fuel. In particular, the present invention relates to a structure of a movable body that opens and closes fuel injection holes.

  Patent Document 1 describes a fuel injection valve that injects fuel into a combustion engine (internal combustion engine). The fuel injection valve is disposed in the fuel flow path, a main body having a fuel injection hole provided at the downstream end of the fuel flow path, and the fuel flow path, and slides along the fuel flow path to A movable body that opens and closes the injection hole, an urging member that urges the movable body to the downstream side of the fuel flow path, and moves the movable body to the upstream side of the fuel flow path against the urging force of the urging member. It has an electromagnet. The movable body is in contact with the main body to close the fuel injection valve, the armature is located upstream of the valve body and receives the urging force by the urging member and the attraction force by the electromagnet, and the valve body And a tubular connecting tube for connecting the armature to each other.

  Patent Document 1 discloses a technique for manufacturing a tubular part constituting a coupling pipe from a plate material. In this technique, a rectangular or parallelogram-shaped metal piece is prepared, and the metal piece is bent into a tubular shape to produce a tubular part that becomes a coupling pipe. According to this technique, the manufacturing cost can be suppressed as compared with a manufacturing method using a tubular material.

JP-A-2-107877

By receiving the urging force of the urging member, a large compressive force is applied to the coupling pipe in the axial direction. At this time, if the rigidity of the coupling pipe in the axial direction is not sufficient, the coupling pipe is greatly plastically deformed, resulting in a malfunction or inability to operate the fuel injection valve.
In a coupling pipe using a tubular part manufactured from a plate material, a slit extending from the upstream end to the downstream end is formed. The coupling pipe in which the slit exists is not easily tensioned in the circumferential direction in the slit, and thus is easily deformed when a compressive force is applied along the axial direction. That is, in the coupling pipe in which the slit exists, the rigidity in the axial direction is significantly reduced. In order to ensure the rigidity of the coupling pipe, for example, it is conceivable to increase its thickness, but in this case, secondary problems such as a reduction in the capacity of the fuel injection valve and an increase in manufacturing cost occur.
In view of the above problems, the present invention provides a technique capable of suppressing a decrease in rigidity of a coupled pipe line in which a slit exists.

  A fuel injection valve according to the present invention includes a main body having a fuel flow path and a fuel injection hole provided at a downstream end of the fuel flow path, and is disposed in the fuel flow path and slides along the fuel flow path. A movable body that opens and closes the fuel injection hole, a biasing member that biases the movable body to the downstream side of the fuel flow path, and an upstream side of the fuel flow path that resists the biasing force of the biasing member. It has an electromagnet to move to. The movable body is in contact with the main body to close the fuel injection valve, the armature is located upstream of the valve body and receives the urging force by the urging member and the attraction force by the electromagnet, and the valve body And a tubular connecting tube connecting the armature. A slit extending from the upstream end to the downstream end is formed in the coupling pipe. The slit formed in the coupling pipe is formed with a displacement portion that extends while the slit is displaced in the circumferential direction with respect to the axis of the coupling pipe. Here, the extension displacement angle of the slit in the displacement portion is set to an angle exceeding 45 degrees.

  The extension displacement angle of the slit here refers to “the direction in which the slit extends toward the downstream end” and “the direction toward the downstream end of the coupling pipe parallel to the axis of the coupling pipe (downstream direction of the axis)”. Means angle. Accordingly, the extension displacement angle of the slit is an angle formed by “the direction in which the slit extends toward the upstream end” and “the direction toward the upstream end of the coupling pipe parallel to the axis of the coupling pipe (the upstream direction of the axis)”. It can also be expressed as Stretch displacement angle of the slit is from 0 degree when the slit extends in the axial downstream direction toward the downstream end, and from 90 degree when the slit extends in the circumferential direction perpendicular to the axial downstream direction toward the downstream end. The range of 180 degrees can be taken when the slit extends in the axial upstream direction toward its downstream end.

In the displacement portion where the slit is displaced in the circumferential direction, both sides of the coupling tube facing each other across the slit are opposed to each other in the axial direction of the coupling tube (however, they do not necessarily face each other). Therefore, when the coupling pipe receives a compressive force in the axial direction, both sides of the coupling pipe come into contact with each other at the displacement portion, and the both sides of the coupling pipe are temporarily connected. As a result, tension is generated in the circumferential direction across the slit in the displacement portion, and deformation of the coupling tube is suppressed. That is, by providing the displacement portion in the slit of the coupling tube, the rigidity in the axial direction of the coupling tube can be significantly improved.
However, in a coupling pipe in which a slit exists, a springback occurs in the direction in which the diameter increases, and both sides of the coupling pipe facing each other across the slit may be separated in the circumferential direction. At this time, if the extension displacement angle of the slit is smaller than 45 degrees, both side sides of the coupling pipe facing each other across the slit are greatly separated in the axial direction as compared to the distance separating in the circumferential direction. In such a state, even when the coupling pipe receives a compressive force in the axial direction, both sides of the coupling pipe facing each other across the slit may not contact each other even in the displacement portion.
On the other hand, when the extension displacement angle of the slit exceeds 45 degrees, when springback occurs in the coupling tube, the distance that both sides of the coupling tube are separated in the axial direction is more than the distance that is separated in the circumferential direction. Can be kept small. Therefore, when the coupling tube receives a compressive force in the axial direction, both side sides of the coupling tube facing each other across the slit more reliably come into contact with each other at the displacement portion.

In the fuel injection valve described above, it is preferable that the extension displacement angle of the slit in the displacement portion is an angle of 90 degrees or more.
When the stretching displacement angle of the slit in the displacement portion is 90 degrees or more, even when both sides of the coupling tube are separated in the circumferential direction by the springback, both sides of the coupling tube are not separated in the axial direction. When the coupling pipe receives a compressive force in the axial direction and both sides of the coupling pipe come into contact with each other at the displacement portion, the sides of the coupling pipe are more strongly connected. Therefore, the rigidity in the axial direction of the coupling pipe is further improved.

In the fuel injection valve described above, it is more preferable that the extension displacement angle of the slit in the displacement portion exceeds 90 degrees.
If the extension displacement angle of the slit in the displacement portion is an angle exceeding 90, both sides of the coupling tube are engaged with each other in the displacement portion. When the coupling pipe receives a compressive force in the axial direction, strong tension is generated in the circumferential direction across the slit in the displacement portion, and deformation of the coupling pipe is strongly suppressed. Therefore, the rigidity in the axial direction of the coupling pipe is remarkably improved.

In the fuel injection valve described above, it is preferable that a plurality of the displacement portions described above are formed in the slit formed in the coupling pipe.
According to this embodiment, when the coupling pipe receives a compressive force in the axial direction, both sides of the coupling pipe facing each other across the slit are connected at a plurality of locations. Therefore, the rigidity in the axial direction of the coupling pipe is further improved.

In the fuel injection valve described above, the slit formed in the coupling pipe has a displacement portion extending while displacing the slit in one circumferential direction with respect to the coupling pipe axis, and the slit in the circumferential direction with respect to the coupling pipe axis. It is preferable that the displacement portions that extend while being displaced to the other of these are alternately formed with a straight portion where the slit extends parallel to the axis of the coupling tube.
In this embodiment, unevenness that meshes with each other is formed on both sides of the coupling pipe facing each other across the slit, and the rigidity in the axial direction of the coupling pipe is further improved. In particular, if the extension displacement angle of the slit in each displacement portion is an angle exceeding 90, unevenness that strongly engages in the circumferential direction is formed on both sides of the coupling tube facing each other across the slit. The rigidity in the axial direction is further improved.

In the above fuel injection valve, when the side wall hole is formed in the side wall of the coupling pipe, at least one displacement portion formed in the slit is within the range in which the side wall hole is formed in the axial direction of the coupling pipe. It is preferable to be located at.
According to this embodiment, it is possible to effectively suppress the decrease in rigidity of the coupling tube due to the presence of the side wall hole.

  According to the present invention, it is possible to suppress a decrease in the rigidity of the coupling pipe line in which the slit exists, and it is possible to manufacture a fuel injection valve having excellent performance at a low manufacturing cost.

First, exemplary embodiments of the present invention are listed.
(Embodiment 1) FIG. 4 shows a movable body 40 embodying the present invention. The movable body 40 is a part for opening and closing the fuel injection hole of the fuel injection valve, and can be suitably used as the movable body 40 of the fuel injection valve 10 (see FIG. 1) of an embodiment described later. As shown in FIG. 4, the movable body 40 includes a valve body 42, an armature 48, and a tubular coupling tube 44 that couples the valve body 42 and the armature 48. The valve body 42 and the armature 48 will be described in detail in the embodiments described later.
The coupling tube 44 is formed with a slit 46 extending from the upstream end 44a to the downstream end 44b. The slit 46 is formed with a displacement portion 46 s that extends while the slit 46 is displaced in the circumferential direction with respect to the axis C of the coupling tube 44. The displacement part 46 s is formed in the middle part of the slit 46. It should be noted that at both end portions of the slit 46 (a part extending from the upstream end 46 a to a certain length and a part extending from the downstream end 46 b to a certain length), the slit 46 with respect to the axis C of the coupling tube 44. Is formed in a straight portion 46p extending in parallel. The coupling pipe 44 has a plurality of side wall holes 44d that open to the side walls thereof. The displacement portion 46s of the slit 46 is located within a range in which the side wall hole 44d is formed with respect to the axial direction of the coupling tube 44 (direction parallel to the axial line C).

FIG. 5 shows an enlarged view of the displacement portion 46 s formed in the slit 46. As shown in FIG. 5, in the displacement part 46s, the extension displacement angle of the slit 46 is 60 degrees. Here, the extension displacement angle of the slit 46 refers to the direction A in which the slit 46 extends toward the downstream end 46b, and the direction toward the downstream end 44b of the coupling tube 44 parallel to the axis C of the coupling tube 44 (downstream of the axis). Direction) is an angle formed by B. Accordingly, even when the coupling pipe 44 is spring-backed and both sides 44f of the coupling pipe 44 facing each other across the slit 46 are separated by a distance D1, both sides 44f of the coupling pipe 44 are separated in the axial direction. The distance is suppressed to a distance D2 that is shorter than the distance D1. Here, D2 = D1 / Tan60 ° <D1. Therefore, in the displacement portion 46s of the slit 46, both sides 44f of the coupling tube 44 continue to approach each other in the axial direction even when the coupling tube 44 is springbacked.
Here, the extension displacement angle of the slit 46 is not limited to 60 degrees. If the extension displacement angle of the slit 46 exceeds 45 degrees, the distance D2 at which the both sides 44f of the coupling tube 44 are separated in the axial direction is larger than the distance D1 at which the both sides 44f of the coupling tube 44 are separated in the circumferential direction. Shorter. Therefore, it is effective to set the extension displacement angle of the slit 46 in the displacement portion 46s to an angle exceeding 45 degrees.

  In the movable body 40 described above, when the coupling pipe 44 receives a compressive force in the axial direction thereof, both side sides 44f of the coupling pipe 44 facing each other across the slit 46 come into contact with each other at the displacement portion 46s. A frictional force is generated between both sides 44f of the coupling tube 44, and the sides 44f are temporarily connected in the circumferential direction. As a result, in the displacement part 46s, tension is generated in the circumferential direction across the slit 46, and deformation of the coupling tube 44 is suppressed. That is, the coupling tube 44 has a relatively high rigidity in the axial direction despite the presence of the slit 46. In particular, when the side wall hole 44d is formed on the side wall of the coupling pipe 44, the rigidity in the axial direction of the coupling pipe 44 is greatly reduced within the range in the axial direction where the side wall hole 44d exists, but is displaced within the range. By forming the portion 46s, the rigidity reduction is effectively suppressed.

  The coupling pipe 44 of the movable body 40 can be manufactured using a tubular part manufactured from a plate material. That is, by preparing a plate material (metal piece) having a shape in which the coupling tube 44 is developed in a plane, and bending the plate material into a tubular shape, a tubular part that becomes the coupling tube 44 can be manufactured. According to this technique, the manufacturing cost of the fuel injection valve 10 can be kept lower than preparing a tubular material according to the diameter of the coupling pipe 44. Further, since the deformation of the coupling pipe 44 during the operation of the fuel injection valve 10 is prevented, a situation such as a malfunction or inability of the fuel injection valve 10 is prevented. Therefore, by adopting the movable body 40, the fuel injection valve 10 having excellent performance can be realized at a low manufacturing cost.

(Embodiment 2) FIG. 6 shows another movable body 40 embodying the present invention. Similarly, the movable body 40 of this form 2 can also be suitably used as the movable body 40 of the fuel injection valve 10 of the embodiment described later. As shown in FIG. 6, the movable body 40 of the second embodiment also has a tubular coupling pipe 44 that couples the valve body 42 and the armature 48, and the coupling pipe 44 has an upstream end 44a. A slit 46 extending to the downstream end 44b is formed.
A displacement portion 46 s is formed in the middle portion of the slit 46 so that the slit 46 extends while being displaced in the circumferential direction with respect to the axis C of the coupling tube 44. Further, at both end portions of the slit 46, rectilinear portions 46p in which the slit 46 extends parallel to the axis C of the coupling tube 44 are formed. Also in the present embodiment, the coupling tube 44 has a plurality of side wall holes 44d, and the displacement portion 46s of the slit 46 is located within the range in which the side wall hole 44d is formed in the axial direction of the coupling tube 44. ing.

FIG. 7 shows an enlarged view of the displacement portion 46s of the second embodiment. As shown in FIG. 7, in the displacement part 46s, the extension displacement angle of the slit 46 is 90 degrees. That is, the direction A in which the slit 46 extends toward the downstream end 46b and the axial downstream direction B of the coupling pipe 44 form an angle of 90 degrees. In the case of such a configuration, a springback occurs in the coupling pipe 44, and even when both side sides 44f of the coupling pipe 44 facing each other across the slit 46 are separated by a distance D1 in the circumferential direction, the displacement portion 46s has the coupling pipe 44. Both side sides 44f keep abutting without separating.
In the movable body 40 according to the second aspect, when the coupling tube 44 receives a compressive force in the axial direction thereof, both side sides 44f of the coupling tube 44 strongly come into contact with each other at the displacement portion 46s of the slit 46, and both side sides 44f of the coupling tube 44 The space is relatively strongly connected. In particular, since both sides 44f of the coupling tube 44 face each other in the axial direction in the displacement portion 46s, a strong frictional force is generated on the sides 44f in the circumferential direction. As a result, strong tension is generated in the circumferential direction across the slit 46 in the displacement portion 46s, and the deformation of the coupling tube 44 is strongly suppressed. That is, the coupling tube 44 has higher rigidity in the axial direction despite the presence of the slit 46.
Also by adopting the movable body 40 of this form 2, the fuel injection valve 10 having excellent performance can be realized at a low manufacturing cost.

(Embodiment 3) FIG. 8 shows another movable body 40 embodying the present invention. Similarly, the movable body 40 of this form 3 can also be suitably used as the movable body 40 of the fuel injection valve 10 of the embodiment described later. As shown in FIG. 8, the movable body 40 of the third form also has a tubular coupling pipe 44 that couples the valve body 42 and the armature 48, and the coupling pipe 44 has an upstream end 44a. A slit 46 extending to the downstream end 44b is formed.
A displacement portion 46 s is formed in the middle portion of the slit 46 so that the slit 46 extends while being displaced in the circumferential direction with respect to the axis C of the coupling tube 44. Further, at both end portions of the slit 46, rectilinear portions 46p in which the slit 46 extends parallel to the axis C of the coupling tube 44 are formed. Also in the present embodiment, the coupling tube 44 has a plurality of side wall holes 44d, and the displacement portion 46s of the slit 46 is located within the range in which the side wall hole 44d is formed in the axial direction of the coupling tube 44. ing.

FIG. 9 shows an enlarged view of the displacement portion 46s of the third embodiment. As shown in FIG. 9, in the displacement part 46s, the extension displacement angle of the slit 46 is 135 degrees. That is, the direction A in which the slit 46 extends toward the downstream end 46b and the axial downstream direction B of the coupling pipe 44 form an angle of 135 degrees. In such a configuration, when the coupling tube 44 is spring-backed and both sides 44f of the coupling tube 44 facing each other across the slit 46 try to separate in the circumferential direction, both sides 44f interfere with each other in the displacement portion 46s. Hold on. That is, in the displacement portion 46s, both side sides 44f of the coupling pipe 44 are engaged in the circumferential direction, and the spring back itself of the coupling pipe 44 is suppressed.
In the movable body 40 of Mode 3, both side sides 44f of the coupling tube 44 are engaged with each other at the displacement portion 46s. Therefore, when the coupling tube 44 receives a compressive force in the axial direction, a stronger tension is generated in the circumferential direction in the displacement portion 46s across the slit 46, and the deformation of the coupling tube 44 is further suppressed. That is, in this movable body 40, the coupling pipe 44 has very high rigidity in the axial direction despite the presence of the slit 46.
Also by adopting the movable body 40 of this form 3, the fuel injection valve 10 having excellent performance can be realized at a low manufacturing cost.

  FIG. 1 is a cross-sectional view showing the configuration of a fuel injection valve 10 embodying the present invention. The fuel injection valve 10 is a valve device that injects fuel pumped by a fuel pump or the like into a combustion chamber of an engine. As shown in FIG. 1, the fuel injection valve 10 includes a main body 20, a movable body 40, a coil spring 50, and an electromagnetic coil 52. The main body 20 has a fuel flow path 28 and a fuel injection hole 36 located at the downstream end of the fuel flow path 28. The movable body 40 is disposed in the fuel flow path 28 of the main body 20, and is supported so as to be slidable along the fuel flow path 28. The movable body 40 opens and closes the fuel injection hole 36 by sliding in the fuel flow path 28. The coil spring 50 urges the movable body 40 to the downstream side (fuel injection hole 36 side) of the fuel flow path 28. The electromagnetic coil 52 constitutes an electromagnet together with the fixed core 24 described later, and moves the movable body 40 to the upstream side (anti-fuel injection hole 36 side) of the fuel flow path 28 against the urging force of the coil spring 50. . That is, the fuel injection valve 10 opens the fuel injection hole 36 and injects fuel when the electromagnetic coil 52 is energized.

The detailed configuration of the fuel injection valve 10 will be described first with respect to the main body 20. The main body 20 mainly includes a fixed core 24, a body 32 positioned on the downstream side of the fuel flow path 28 with respect to the fixed core 24, and a nonmagnetic ring 30 that couples the fixed core 24 and the body 32 in a liquid-tight manner. It has.
The fixed core 24 is made of a magnetic material, and more specifically is made of electromagnetic stainless steel. The fixed core 24 has a generally cylindrical shape, and has a through hole that constitutes a part of the fuel flow path 28. In the through hole of the fixed core 24, a fuel filter 22 for removing foreign matters from the fuel, a spring pin 26 in contact with the upstream end of the coil spring 50, and the coil spring 50 are disposed from the upstream side. .

The body 32 is made of a magnetic material, and more specifically is made of electromagnetic stainless steel. The body 32 has a generally cylindrical shape and has a through hole that constitutes a part of the fuel flow path 28. A movable body 40 is slidably accommodated in the through hole of the body 32. Further, a valve seat member 34 is provided in the downstream portion of the through hole of the body 32.
The valve seat member 34 is a cylindrical member formed of metal, and the downstream end of the through hole is reduced in diameter to constitute the fuel injection hole 36. An orifice plate 38 for adjusting the opening area of the fuel injection hole 36 is provided on the downstream end face of the valve seat member 34. Due to the biasing force of the coil spring 50, the valve body 42 provided in the movable body 40 abuts the valve seat member 34 in a liquid-tight manner. As a result, the fuel injection hole 36 is closed.
The nonmagnetic ring 30 is an annular member made of a nonmagnetic material, and more specifically is made of austenitic stainless steel (SUS304). The nonmagnetic ring 30 is interposed between the body 32 and the fixed core 24, and liquid-tightly connects the through hole of the body 32 and the through hole of the fixed core 24. The nonmagnetic ring 30 is provided at a position surrounding the opposing ends of the armature 48 and the fixed core 24 from the periphery.

The coil spring 50 is disposed in the fuel flow path 28. The coil spring 50 is located between the spring pin 26 and the movable body 40. The coil spring 50 is in a sufficiently compressed state and urges the movable body 40 toward the downstream side where the fuel injection hole 36 is located.
The electromagnetic coil 52 is provided so as to go around the fixed core 24. The electromagnetic coil 52 is electrically connected to an external control unit (not shown), and a current is supplied at a timing at which fuel should be injected. When the electromagnetic coil 52 is energized, the armature 48 of the fixed core 24 and the movable body 40 is magnetized, and the movable body 40 is attracted upstream so as to separate from the fuel injection hole 36. Thereby, the fuel injection hole 36 is opened, and fuel is injected from the fuel injection hole 36. The electromagnetic coil 52 is fixed integrally with the main body 20 by a resin holder 58 formed by insert molding.
The resin holder 58 is provided with a connector 56 to which a wire harness can be connected. A plurality of terminal pins 54 that are electrically connected to the electromagnetic coil 52 are arranged on the connector 56. The fuel injection valve 10 is electrically connected to an external control unit via a wire harness.

Next, the configuration of the movable body 40 will be described with reference to FIGS. 1 and 2. FIG. 2 shows the movable body 40 of this embodiment as a single unit. As shown in FIG. 1 and FIG. 2, the movable body 40 includes a valve body 42, an armature 48 positioned on the upstream side with respect to the valve body 42, and a tubular coupling pipe that joins the valve body 42 and the armature 48. 44.
The valve body 42 has a spherical shape and is formed of a metal material. The valve body 42 is located at the downstream end of the movable body 40. The valve body 42 is pressed against the valve seat member 34 by the biasing force of the coil spring 50, and comes into liquid-tight contact with the valve seat member 34 to close the fuel injection hole 36.
The armature 48 (also referred to as a movable core) is made of a magnetic material, and more specifically is made of electromagnetic stainless steel. The armature 48 is in contact with the downstream end of the coil spring 50. That is, the urging force by the coil spring 50 is applied to the armature 48. Further, when the electromagnetic coil 52 is energized, an attractive force to the magnetized fixed core 24 is also applied to the armature 48.

The coupling tube 44 is made of a metal material. The upstream end 44a of the coupling pipe 44 is press-fitted into the through-hole of the armature 48, and the coupling pipe 44 and the armature 48 are welded over the entire circumference (except for the slit 46). Further, the downstream end 44b of the coupling pipe 44 is also welded to the valve body 42 over the entire circumference (except for the slit 46). The coupling tube 44 is manufactured by bending a plate-shaped metal piece, and a slit 46 extending from the upstream end 44a to the downstream end 44b is formed. The coupling pipe 44 is formed with a plurality of side wall holes 44d through which fuel passes.
As shown in FIG. 2, the slit 46 includes a rectilinear portion 46 p that extends parallel to the axis C of the coupling tube 44, and the slit 46 is displaced in the circumferential direction with respect to the axis C of the coupling tube 44. However, a plurality of displacement portions 46s that are extended are formed. The plurality of rectilinear portions 46p and the displacement portions 46s are alternately formed from the upstream end 46a to the downstream end 46b of the slit 46. In addition, one displacement portion 46 s is located in a range where the side wall hole 44 d is formed with respect to the axial direction of the coupling pipe 44.

  In all the displacement portions 46s, the extension displacement angle θ of the slit 46 is 135 degrees which is larger than 90 degrees. That is, the angle θ formed by the direction A in which the slit 46 extends toward the downstream end 46b and the axial downstream direction B is 135 degrees which is greater than 90 degrees. Accordingly, concave and convex shapes that engage with each other are formed on both sides 44f of the coupling tube 44 that face each other across the slit 46. That is, on both sides 44f of the coupling tube 44, a convex portion with a wide top and a concave portion with a wide bottom are formed alternately, and the convex and concave portions on both sides 44f of the coupling tube 44 are engaged with each other. Yes. Thereby, the spring back of the coupling pipe 44 is suppressed, and the width of the slit 46 in the rectilinear portion 46p is very narrow. Here, the strength of the welding between the coupling pipe 44 and the valve body 42 and the welding between the coupling pipe 44 and the armature 48 increases as the circumferential distance between the both ends 44a and 44b of the slit 46 decreases.

Next, the operation of the fuel injection valve 10 will be described. Fuel that has been pressurized from the upstream end (the upper end in FIG. 1) of the fixed core 24 flows into the fuel injection valve 10. As shown by arrow F in FIG. 1, the fuel that has flowed into the filter member 22, the through hole of the spring pin 26, the through hole of the fixed core 24, the through hole of the armature 48, the shaft hole of the coupling pipe 44, and the side wall hole 44 d. It passes through and reaches the valve portion composed of the valve seat member 34 and the valve body 42.
When no current is supplied to the electromagnetic coil 52, the valve element 42 is in liquid-tight contact with the valve seat member 34 by the biasing force of the coil spring 50. In this case, the fuel injection hole 36 is closed by the valve body 42, and fuel is not injected from the fuel injection hole 36.
On the other hand, when a current is passed through the electromagnetic coil 52, the movable body 40 is attracted to the fixed core 24 by the generated magnetic force. That is, the movable body 40 moves to the upstream side against the urging force of the coil spring 50. As a result, the valve body 42 is separated from the valve seat member 34, the fuel injection hole 36 is opened, and fuel is injected from the fuel injection hole 36.

  When the electromagnetic coil 52 is not energized, the movable body 40 is pressed against the valve seat member 34 by the biasing force of the coil spring 50. At this time, since the urging force of the coil spring 50 is applied to the armature 48, a strong compressive force acts on the coupling tube 44 in the axial direction thereof. Usually, when the slit 46 is formed in the coupling pipe 44, the rigidity of the coupling pipe 44 in the axial direction is significantly reduced. More specifically, when the slit 46 is formed in the coupling pipe 44, since the circumferential tension does not act between both sides 44 f of the coupling pipe 44 facing each other across the slit 46, the coupling pipe 44 is strong in the axial direction. When a compressive force is applied, the coupling tube 44 is easily deformed while the slit 46 is widened. Therefore, the coupling pipe 44 in which the slit 46 exists may be deformed without being able to withstand the compressive force in the axial direction, which may cause problems such as malfunction or inability of the fuel injection valve 10.

  However, in the fuel injection valve 10 of the present embodiment, both side sides 44f of the coupling pipe 44 facing each other across the slit 46 are engaged with each other in the circumferential direction. Therefore, when the coupling pipe 44 receives a compressive force in the axial direction, tension acts in the circumferential direction across the slit 46 between the both sides 44 f of the coupling pipe 44. Thereby, deformation of the coupling tube 44 is suppressed. That is, in this movable body 40, the coupling pipe 44 has very high rigidity in the axial direction despite the presence of the slit 46. In particular, since a plurality of displacement portions 46 s are arranged over a wide range in the slit 46, a reduction in rigidity due to the slit 46 is suppressed to be extremely small. Since the coupling pipe 44 has sufficient rigidity in the axial direction, problems such as malfunction and inoperability of the fuel injection valve 10 due to deformation of the coupling pipe 44 are solved.

  In the fuel injection valve 10 of the present embodiment, the coupling pipe 44 of the movable body 40 can be manufactured using a tubular part manufactured from a plate material. That is, by preparing a metal piece having a shape in which the coupling tube 44 is developed in a plane and bending the plate material into a tubular shape, a tubular part that becomes the coupling tube 44 can be manufactured. Both sides 44f of the coupling tube 44 have a complicated shape, but there is no particular problem with press working using a mold. The manufacturing cost of the fuel injection valve 10 can be kept lower than preparing a tubular material according to the diameter of the coupling pipe 44.

  FIG. 3 shows another movable body 40 that can be employed in the fuel injection valve 10 described above. In the movable body 40 shown in FIG. 3, the stretching displacement angle θ at the displacement portion 46 s of the slit 46 is designed to be 90 degrees compared to the movable body 40 shown in FIG. 2. For this reason, in this movable body 40, a springback occurs in the coupling tube 44, and even if both side sides 44f of the coupling tube 44 are separated in the circumferential direction, the distance between the slits 46 in the displacement portion 46s does not change. In the movable body 40, the slit 46 in the displacement portion 46s is intentionally spaced.

  In the fuel injection valve 10 using the movable body 40 shown in FIG. 3, when the coupling pipe 44 receives a compressive force in the axial direction, both side sides 44 f of the coupling pipe 44 abut against each displacement portion 46 s of the slit 46. Fit. Therefore, when both side sides 44f of the coupling tube 44 try to separate in the circumferential direction, a frictional force is generated between both side sides 44f of the coupling tube 44, and a tension is exerted between the both side sides 44f of the coupling tube 44 in the circumferential direction. Will occur. That is, both side sides 44f of the coupling pipe 44 are temporarily connected in the circumferential direction. Accordingly, even when an axial compressive force is applied to the coupling tube 44, deformation of the coupling tube 44 is significantly suppressed. In other words, the coupling tube 44 also has sufficient rigidity in the axial direction despite the presence of the slit 46.

Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, in the above-described embodiment, the slit 46 is provided with the rectilinear portion 46s (the portion where the stretching displacement angle is 0 degree), but the rectilinear portion 46s is displaced in the circumferential direction at an appropriate angle with respect to the axial direction. May be. However, at both end portions of the slit 46, the slit 46 may be a rectilinear portion 46p. In this case, since the interval in the circumferential direction at both ends 46a and 46b of the slit 46 is narrower than when the slit 46 is displaced in the circumferential direction, welding between the coupling pipe 44 and the valve body 42, and the coupling pipe The welding between the armature 44 and the armature 48 can be performed firmly.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

Sectional drawing which shows the structure of the fuel injection valve of an Example. The figure which shows the movable body of the said Example. The figure which shows another movable body. The figure which shows the 1st typical example of the movable body which implemented this invention. The figure explaining the displacement part of the slit provided in the 1st typical example. The figure which shows the 2nd typical example of the movable body which implemented this invention. The figure explaining the displacement part of the slit provided in the 2nd typical example. The figure which shows the 3rd typical example of the movable body which implemented this invention. The figure explaining the displacement part of the slit provided in the 3rd typical example.

Explanation of symbols

10: Fuel injection valve 20: Main body 22: Fuel filter 24: Fixed core 26: Spring pin 28: Fuel flow path 30: Nonmagnetic ring 32: Body 34: Valve seat member 36: Fuel injection hole 40: Movable body 42: Valve Body 44: Coupling tube 44d: Side wall hole 46: Slit 46p: Straight part 46s of slit: Displacement part 48 of slit: Armature 50: Coil spring 52: Electromagnetic coil

Claims (6)

A main body having a fuel flow path and a fuel injection hole provided at a downstream end of the fuel flow path;
A movable body that is disposed in the fuel flow path and slides along the fuel flow path to open and close the fuel injection hole;
A biasing member that biases the movable body to the downstream side of the fuel flow path;
An electromagnet that moves the movable body to the upstream side of the fuel flow path against the biasing force of the biasing member;
The movable body is in contact with the main body and closes the fuel injection valve, is located upstream of the valve body, and receives the biasing force by the biasing member and the suction force by the electromagnet. An armature, and a tubular coupling pipe coupling the valve body and the armature;
The coupling pipe is formed with a slit extending from the upstream end to the downstream end,
The slit is formed with a displacement portion that extends while the slit is displaced in the circumferential direction with respect to the axis of the coupling pipe,
The fuel injection valve, wherein an extension displacement angle of the slit in the displacement portion is an angle exceeding 45 degrees.   The fuel injection valve according to claim 1, wherein an extension displacement angle of the slit in the displacement portion is an angle of 90 degrees or more.   The fuel injection valve according to claim 2, wherein an extension displacement angle of the slit in the displacement portion is an angle exceeding 90 degrees.   4. The fuel injection valve according to claim 1, wherein a plurality of the displacement portions are formed in the slit. 5.   The slit is extended while the slit is displaced in one circumferential direction with respect to the axis of the coupling tube, and the slit is extended while being displaced in the other circumferential direction with respect to the axis of the coupling tube. 5. The fuel injection valve according to claim 4, wherein the displacing portions are alternately formed with a rectilinear portion in which the slit extends parallel to the axis of the coupling pipe. The coupling pipe is formed with a side wall hole that opens to the side wall,
6. The fuel according to claim 1, wherein at least one displacement portion of the slit is located within a range in which the side wall hole is formed with respect to an axial direction of the coupling pipe. Injection valve.

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