JP2010077865A - Fuel injection valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a fuel injection valve that improves the atomization of fuel spray while suppressing variation in flow rate accuracy and spray characteristics and maintaining the directivity of the spray. <P>SOLUTION: A thin part 11c with an upstream side recessed is provided at a central part of an injection hole plate 11 and a tapered face 11d having an angle α larger than a seat angle β is provided on the outer peripheral side of the thin part 11c. An injection hole inlet part is disposed over a virtual circle 11e formed of a virtual conical face extended to the downstream side of a valve seat part 10a and the tapered face 11d crossing, and an outlet part of the injection hole 12 is disposed on the radially outer side with respect to the inlet part. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fuel injection valve used for supplying fuel to an internal combustion engine of an automobile, and more particularly to a fuel injection valve that promotes atomization in spray characteristics and suppresses variation in spray shape. .

  In recent years, as exhaust gas regulations for automobiles and the like have been strengthened, there is a demand for improvement in the degree of freedom and atomization of the direction of fuel spray injected from the fuel injection valve. In particular, various studies have been made on atomization of fuel spray. For example, there is a fuel injection valve as disclosed in Japanese Patent Application Laid-Open No. 2007-1000051 (hereinafter referred to as Patent Document 1).

  Patent Document 1 discloses a fuel injection valve having a plurality of injection holes. In this fuel injection valve, a flat surface substantially parallel to the injection hole plate is formed at the tip of the valve body. The inlet portion of the injection hole is disposed inside the virtual envelope where the extension of the inner wall on the downstream side of the seat portion and the upstream plane of the injection hole plate intersect, and outside the flat surface of the tip of the valve body. The perpendicular distance h between the flat surface formed at the tip of the valve body in the valve-opened state and the upstream plane of the nozzle hole plate with respect to the nozzle hole inlet diameter d has a relationship of h <d. Is formed at a predetermined angle with respect to the thickness direction of the nozzle hole plate (see, for example, Patent Document 1).

  As another conventional technique, there is a fuel injection valve as shown in FIG. The fuel injection valve shown in FIG. 7 has a plurality of injection holes 70, and protrudes downstream in the central part of the injection hole plate 72 facing the front end part of the valve body 71 substantially parallel to the front end part of the valve body 71. A projecting portion 72a is formed. The fuel injection valve is formed on a virtual envelope where the extension of the downstream inner wall of the seat portion 74 of the valve seat 73 and the upstream side surface of the injection hole plate 72 intersect, and on the outer side of the protrusion 72a. The shortest distance h between the distal end portion of the valve body 71 and the upstream side surface of the nozzle hole plate 72 in the open state is configured in a relationship of h <d with respect to the nozzle hole inlet diameter d. Further, the nozzle hole 70 is configured to be inclined at a predetermined angle with respect to the thickness direction of the nozzle hole plate 72.

JP 2007-1000051 (paragraph 0013, FIG. 2)

  According to the conventional fuel injection valve, the flow of the fuel in the cavity surrounded by the valve body tip, the valve seat, and the nozzle hole plate reaches the nozzle hole plate after reaching the nozzle hole plate, or Since the cavity flow path area rapidly decreases up to the projection of the nozzle hole plate, the flow toward the center of the virtual envelope (reference numeral L1 in FIG. 7) is strengthened. In addition, due to the relationship of the shortest distance h between the tip of the valve body and the nozzle hole plate <the nozzle hole inlet diameter d, a flow that passes between the nozzle holes and faces the center of the nozzle hole plate makes a U-turn and flows toward the nozzle hole ( By suppressing the sign L2) in FIG. 7, the inflow to the nozzle hole from one direction is strengthened. As a result, a liquid film is formed by flow separation at the injection hole inlet, and the fuel is pressed against the injection hole wall, so that the flow in the injection hole flows along the curvature of the injection hole, It is said that the atomization can be promoted while suppressing the excessive spray diffusion by diffusing as a crescent-shaped liquid film from the nozzle hole outlet.

  However, as shown in FIG. 7, after the fuel flowing along the seat portion 74 of the valve seat 73 enters the inlet portion of the nozzle hole 70, it is pressed against the nozzle hole wall and follows the curvature of the nozzle hole 70. When converted into a flow, an optimal nozzle hole length is required to form a crescent-shaped liquid film inside the nozzle hole 70, and if it is too long, the fuel goes around the nozzle hole 70 and forms a streaky spray. Therefore, even if it is too short, the conversion into the flow along the curvature of the nozzle hole 70 is not sufficient, resulting in a streaky spray.

  Further, in a cross section passing through the axis of the valve body 71 and the center of the nozzle hole 70, the first parallel line 75 that passes through the radial inner side of the nozzle hole 70 and is parallel to the seat portion 74 of the valve seat 73, and the nozzle hole 70. The distance between the second parallel line 76 passing through the outer side of the valve seat 73 and parallel to the seat portion 74 of the valve seat 73 is such that the virtual conical surface extending the seat portion 74 of the valve seat 73 downstream and the injection hole 70 are arranged. The maximum is 90 ° with respect to the plane of the nozzle hole plate 72, and 0 when the angle is 0 °.

  In the structure of the conventional fuel injection valve, since the inlet portion of the injection hole 70 is arranged on a plane orthogonal to the axis of the valve body 71, the seat part 74 of the valve seat 73 and the arrangement surface of the injection hole 70 And the distance between the first parallel line 75 and the second parallel line 76 is also large. Therefore, the fuel that passes through the radially outer side of the inlet portion of the nozzle hole 70 and collides with the radially inner side of the nozzle hole wall, and the fuel that collides with the radially inner side of the inlet portion of the nozzle hole 70, The distance to the outlet is different, and there is no structure that has the optimum nozzle hole length for atomization.

  By the way, in a fuel injection valve that injects fuel from a plurality of nozzle holes provided in the nozzle hole plate, it is necessary to increase the nozzle hole diameter for application to a large flow rate specification. The outside distance will increase. In addition, in order to realize a large injection angle, it is necessary to increase the inclination angle of the nozzle hole, the flatness of the inlet shape of the nozzle hole increases, and the distance between the radially inner and outer sides at the inlet part of the nozzle hole increases. turn into.

  In the structure of the conventional fuel injection valve, as shown in FIG. 7, the inlet portion of the injection hole 70 is arranged on a plane perpendicular to the axis of the valve body 71. When applied to, the distance between the first parallel line 75 and the second parallel line 76 increases due to the flow rate and the spray specifications, and the spray particle size deteriorates.

  Further, when the inclination angle of the injection hole 70 is increased, in the removability of the injection hole 70 by the press, dripping and burring on the inlet side in the drawing direction and the fracture surface on the outlet side in the drawing direction increase, so that spray variation and flow rate are increased. There is a problem that the variation becomes large.

  On the other hand, in a fuel injection valve that injects fuel from a plurality of nozzle holes provided in the nozzle hole plate, when the nozzle hole plate is welded to the valve seat, the welded part cools and shrinks when solidified. The plate is pulled in the radial direction, and residual stress is generated in the valve seat. For this reason, it is known that the roundness of the seat portion of the valve seat after the nozzle hole plate welding is lowered and the valve oil tightness is deteriorated. In order to relieve the residual stress, it is effective to reduce the material hardness of the nozzle hole plate, but since the hole punching ability in the press deteriorates, spraying, flow rate variation reduction and valve oil tightness There are also problems that cannot be improved at the same time.

  The present invention has been made to solve the problems of the conventional apparatus as described above, and improves atomization of fuel spray while suppressing variation in flow rate accuracy and spray characteristics and maintaining spray directivity. An object of the present invention is to obtain a fuel injection valve as described above.

The fuel injection valve according to the present invention has a valve body that opens and closes a valve seat, receives an operation signal from a control device, operates the valve body, and is provided in a plurality of nozzle holes mounted on the downstream side of the valve seat. A fuel injection valve that injects fuel from the nozzle hole and has the following requirements.
(1) A part of the upstream end face of the nozzle hole plate is recessed to provide a thin portion that extends in the radial direction around the axis of the valve body.
(2) A tapered surface is provided at a portion connecting the thin portion and the nozzle hole plate thickness on the outer peripheral side thereof.
(3) The angle of the tapered surface is made larger than the seat angle of the valve seat so that the virtual conical surface extended to the downstream side of the valve seat portion intersects the tapered surface to form one virtual circle.
(4) The inlet portion of the nozzle hole is arranged so as to cover the virtual circle on the tapered surface.
(5) The outlet part of the nozzle hole is arranged radially outward with respect to the inlet part.
(6) The perpendicular distance h between the valve body tip of the valve body shaft center portion and the thin-walled portion in the valve body opened state has a relationship of h <d with respect to the injection hole inlet diameter d.

  According to the fuel injection valve according to the present invention, atomization in the spray characteristics can be promoted and variations in the spray shape can be suppressed.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a preferred embodiment of a fuel injection valve according to the present invention will be described with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
1 is a cross-sectional view of a fuel injection valve according to Embodiment 1 of the present invention, and FIG. 2 is a detailed cross-sectional view of a tip portion of the fuel injection valve according to Embodiment 1 of the present invention.
In FIG. 1, a fuel injection valve 1 includes a solenoid device 2, a housing 3 that is a yoke portion of a magnetic circuit, a core 4 that is a fixed core portion of the magnetic circuit, a coil 5, an armature 6 that is a movable core portion of the magnetic circuit, and A valve device 7 is provided. The valve device 7 includes a valve body 8, a valve main body 9, and a valve seat 10.

  The valve body 9 is welded after being press-fitted into the outer diameter portion of the core 4, and the armature 6 is welded after being press-fitted into the valve body 8. A nozzle hole plate 11 is attached to the valve seat 10 in a state where it is connected to the downstream side of the valve seat by a welded portion 11a, and after being inserted into the valve body 9, it is connected by a welded portion 11b. As shown in FIG. 2, the nozzle hole plate 11 is provided with a plurality of nozzle holes 12 that are inclined and penetrated in the thickness direction.

Next, the opening / closing operation of the fuel injection valve in FIG. 1 will be described.
When an operation signal is sent from a control device (not shown) of the internal combustion engine to a drive circuit (not shown) of the fuel injection valve 1, a current is passed through the coil 5 of the fuel injection valve 1, and the amuar 6, the core 4, Magnetic flux is generated in a magnetic circuit constituted by the housing 3 and the valve body 9, and the armature 6 is attracted to the core 4 side. As a result, the valve body 8 that is integral with the armature 6 is separated from the valve seat portion 10a (see FIG. 2), and a gap is formed between the valve body 8 and the valve seat portion 10a. Then, as shown in FIG. 2, the fuels L1 and L2 pass through the gap between the valve body 8 and the valve seat portion 10a from the chamfered portion 13a of the ball 13 welded to the tip of the valve body 8, and then a plurality of fuels L1 and L2 It is injected from the injection hole 12 into the engine intake pipe.

  When an operation stop signal is sent from the control device of the internal combustion engine to the drive circuit of the fuel injection valve 1, the energization of the current of the coil 5 is stopped, the magnetic flux in the magnetic circuit is reduced, and the valve body 8 is moved in the valve closing direction. The compression spring 14 that is pressed closes the gap between the valve body 8 and the valve seat portion 10a, and fuel injection ends.

  The valve body 8 slides on the guide portion of the valve body 9 by the side surface 6a of the armature 6 and the guide 13b, and the upper surface 6b of the armature 6 contacts the lower surface of the core 4 in the valve open state. Since the guide 13b is a means for restricting the non-coaxiality (swing) of the valve body 8 in the radial direction with respect to the valve seat surface, the clearance is preferably set as small as possible. In order to make the durable wear within an allowable limit, the thickness is set to 10 μm or less (one-side clearance of 5 μm or less).

Next, the configuration and operation of the main part of the fuel injection valve according to Embodiment 1 of the present invention will be described with reference to FIG.
As shown in FIG. 2, the fuel injection valve 1 according to Embodiment 1 has a thin wall that extends in the radial direction around the axis of the valve body 8 by recessing a part of the upstream end face of the injection hole plate 11. A tapered surface 11d is provided at a portion connecting the thin wall portion 11c and the upstream end surface of the nozzle hole plate 11 on the outer peripheral side thereof on the upstream end surface of the nozzle hole plate 11. Further, the angle α of the tapered surface 11d is set to the seat of the valve seat portion 10a so that the virtual conical surface 10b extending to the downstream side of the valve seat portion 10a and the tapered surface 11d intersect to form one virtual circle 11e. It is larger than the angle β.

  Further, the outlet portion of the injection hole 12 is arranged on the radially outer side with respect to the inlet portion, and the inlet portion of the injection hole 12 is arranged so as to cover the virtual circle 11e on the tapered surface 11d. The perpendicular distance h between the distal end of the axial center portion of the valve body 8 and the thin portion 11c in the state has a relationship of h <d with respect to the nozzle hole inlet diameter d.

  Since the fuel injection valve according to Embodiment 1 is configured as described above, a liquid film 15 is formed by flow separation at the inlet of the injection hole 12, and the fuel is pressed against the injection hole wall 12a. Then, the fuel flow in the injection hole 12 becomes a flow 16 along the curvature of the injection hole 12 and promotes mixing with the air 17 in the injection hole 12 and diffuses as a crescent-like liquid film 18 from the injection hole outlet. Therefore, atomization is promoted.

  Further, by providing the nozzle plate 11 with the tapered surface 11d, the diameter of the inlet portion of the nozzle hole 12 in the cross section passing through the axis of the valve body 8 and the center of the nozzle hole 12 regardless of the flow rate specification or the spray specification. A first parallel line 19 passing through the inner side 12b and parallel to the valve seat portion 10a, and a second parallel line 20 passing through the radially outer side 12c of the inlet portion of the nozzle hole 12 and parallel to the valve seat portion 10a. The distance between can be reduced. Therefore, the distance between the point where the fuel passes through the radially outer side 12c of the inlet portion of the nozzle hole 12 and collides with the radially inner side 12d of the nozzle hole wall and the radially inner side 12b of the inlet portion of the nozzle hole 12 is small, The optimum nozzle hole length for atomizing the fuel that has passed through the radially outer side 12c of the inlet part of the nozzle hole 12 and the radially inner side 12b of the inlet part of the nozzle hole 12 can be made closer. For this reason, spray atomization is possible regardless of the flow rate specification or the spray specification.

  Further, in the injection hole punching performance of the specification in which the inclination angle of the injection hole 12 is large, the injection hole inclination angle with respect to the tapered surface 11d is smaller than that of the conventional technique without the tapered surface 11d. When pressing to the outlet side, sagging or burrs on the inlet side of the nozzle hole 12, and when pressing from the outlet side of the nozzle hole 12 to the inlet side, the fracture surface on the inlet side of the nozzle hole 12 decreases, This has the effect of reducing flow rate variation.

Embodiment 2. FIG.
Next, a fuel injection valve according to Embodiment 2 of the present invention will be described. FIG. 3 shows a cross-sectional view of the fuel injection valve according to the second embodiment.
In FIG. 3, the fuel injection valve 30 according to the second embodiment has a thin portion 31 c provided in the injection hole plate 31 provided with a protrusion 32 that protrudes downstream substantially parallel to the distal end portion of the valve body 8. Is. Other configurations are the same as those of the first embodiment, and the description thereof is omitted by giving the same reference numerals.

  The fuel injection valve according to Embodiment 2 can reduce the distance H from the valve seat portion 10a to the downstream end face of the valve seat 10 by the above configuration, and extends to the downstream side of the valve seat portion 10a. The virtual circle 11e formed by intersecting the virtual conical surface 10b and the tapered surface 11d can be further increased. The reason why the distance H from the valve seat portion 10a to the downstream end face of the valve seat 10 can be reduced is as follows. That is, the distance H from the valve seat portion 10a to the downstream end face of the valve seat 10 can be reduced only to the extent that the tip of the valve body 8 and the injection hole plate 31 do not contact when the valve body 8 is closed. Since the protrusion 32 is provided as in the fuel injection valve 30 according to the second embodiment, the contact between the tip end portion of the valve body 8 and the injection hole plate 31 can be avoided, so that the distance H can be reduced.

  Accordingly, the nozzle holes 12 can be arranged more radially outward, and can be arranged so that the distance between the nozzle holes 12 does not approach even when the nozzle hole diameter is increased in application to a large flow rate specification. Accordingly, the interference between the sprays ejected from the respective nozzle holes 12 can be suppressed, and the atomization of the spray is not hindered by the large flow rate.

  Further, under high temperature negative pressure, a part of the fuel in the cavity evaporates to become a gas-liquid two-layer flow, which causes a flow rate decrease and a spray change. According to the present embodiment, the valve seat portion 10a By reducing the distance H from the downstream end surface of the valve seat 10 to the valve body 10, the volume (dead volume) surrounded by the valve body 8, the valve seat 10, and the nozzle hole plate 31 when the valve is closed can be reduced. The amount of fuel evaporation in the dead volume under high-temperature negative pressure is small, and it has the effect of suppressing changes in flow characteristics (static flow, dynamic flow) and spray characteristics (spray shape, spray particle size) associated with atmospheric changes. is there.

Embodiment 3 FIG.
Next, a fuel injection valve according to Embodiment 3 of the present invention will be described. FIG. 4 shows a cross-sectional view of the fuel injection valve according to the third embodiment.
The fuel injection valve 40 according to the third embodiment is provided with a thin portion 41c in the nozzle hole plate 41, and the thin portion 41c is substantially axisymmetric with respect to the valve seat shaft 42 and has a circular arc-shaped cross section. 43, and the welded portion 11 a between the valve seat 10 and the nozzle hole plate 41 is also substantially axially symmetric with respect to the valve seat shaft 42. Other configurations are the same as those of the first embodiment, and the description thereof is omitted by giving the same reference numerals.

  According to the fuel injection valve according to the third embodiment, after the nozzle hole plate 41 is welded to the valve seat 10, when the welded portion 11a cools and hardens, it contracts in the direction indicated by the arrow A in FIG. The nozzle hole plate 41 inside the welded portion 11a is pulled in the radial direction and deformed in a direction in which the height of the projection 43 becomes smaller.

  Since the residual stress generated in the valve seat 10 after welding is relieved by this deformation, the roundness of the valve seat portion 10a due to the welding of the nozzle hole plate 41 as compared with the case where the protrusion 43 is not provided on the nozzle hole plate 41. Is effective in reducing the deterioration of valve oil tightness. In addition, since the injection hole 12 is arranged on the outer peripheral side of the protrusion 43, the deformation of the injection hole 12 is limited only in the radial direction with respect to the axis of the fuel injection valve 40, so the injection hole plate after welding No change in the nozzle hole tilt angle due to the deformation of 41 occurs, and no variation in the injection direction due to welding variations.

Embodiment 4 FIG.
Next, a fuel injection valve according to Embodiment 4 of the present invention will be described. FIG. 5 shows a cross-sectional view of the fuel injection valve according to the fourth embodiment.
In the fuel injection valve 50 according to Embodiment 4, the injection hole plate 51 is provided with a thin portion 51c, and the thin portion 51c is a flat surface. A flat portion 13c substantially parallel to the flat surface is provided at the distal end portion of the valve body 8, and the outermost diameter φD of the flat portion 13c provided at the distal end portion of the valve body 8 is set to the respective inlets in all the nozzle holes 12. It is smaller than the inscribed circle of the part. Other configurations are the same as those of the first embodiment, and the description thereof is omitted by giving the same reference numerals.

  According to the fuel injection valve according to the fourth embodiment, an effect similar to that of the second embodiment can be obtained, and a low-cost fuel injection valve can be obtained. The reason why a low-cost fuel injection valve can be obtained is as follows.

Usually, the nozzle hole plate is manufactured while feeding the belt-like hoop material in the following process for cost reduction.
<Hole hole plate manufacturing process>
Coining molding (hoop material) → injection hole processing (hoop material)
→ Deburring the nozzle hole (hoop material) → Cut out as a single plate

  In this manufacturing process, if the projection of the nozzle hole plate described in the second embodiment or the fourth embodiment is formed in the state of the hoop material, the feedability is lowered during forward feeding, and the work at the time of deburring the nozzle hole is performed. Therefore, it is necessary to form the protrusions in the final process of cutting out as a single plate. However, since a protrusion molding facility (for example, a press device, a die) is required separately from the coining molding machine, the formation of the protrusion on the nozzle hole plate increases the cost. In addition, in order to save space in the production line, when the nozzle hole plate production lines are arranged in parallel, it is necessary to wind up the hoop material once in order to flow the hoop material to the adjacent production line. There is also a problem that cannot be rolled up.

  On the other hand, as shown in the fourth embodiment, instead of forming a protrusion on the nozzle hole plate, a flat part 13c is provided at the tip of the valve body 8, and when the nozzle hole 12 is processed, the flat part 13c is formed. Can be processed. Therefore, no special equipment such as a projection forming equipment is required, and a low-cost fuel injection valve can be obtained.

Embodiment 5 FIG.
Next, a fuel injection valve according to Embodiment 5 of the present invention will be described. In the fuel injection valve according to the fifth embodiment, the thin portion and the tapered surface of the nozzle hole plate described in the first to fourth embodiments are molded by coining.

  As described above, by molding the thin-walled portion and the tapered surface of the nozzle hole plate by coining, the portion where the nozzle hole is arranged is cured by coining, and the nozzle hole removability in the press is improved. It is possible to reduce the material hardness of the nozzle hole plate in consideration of tightness, and there is an effect that it is possible to achieve both reduction of spray and flow rate variation and improvement of valve oil tightness.

Embodiment 6 FIG.
Next, a fuel injection valve according to Embodiment 6 of the present invention will be described. FIG. 6 shows a cross-sectional view of the fuel injection valve according to the sixth embodiment.
In the fuel injection valve 60 according to the sixth embodiment, the distal end portion 13 of the valve body 8 is configured in a ball shape, and a first flat surface 13d parallel to the axial center of the valve body 8 and a first surface are formed on the ball outer peripheral portion. A fuel passage is constituted by a plurality of grooves 13f formed by a second plane 13e which is orthogonal to the plane 13d and is also parallel to the axis of the valve body 8. Other configurations are the same as those of the third embodiment, and the description thereof is omitted by giving the same reference numerals.

  According to the fuel injection valve according to the sixth embodiment, more fuel passages can be easily formed by forming a uniform sheet flow in the circumferential direction, and the fuel in which the sheet flow enters the nozzle hole inlet The injection valve has an effect of reducing spray variation.

  The fuel injection valve according to the present invention can be used as a fuel injection valve used for supplying fuel to an internal combustion engine of an automobile.

It is sectional drawing of the fuel injection valve which concerns on Embodiment 1 of this invention. It is a detailed sectional view of the tip part of the fuel injection valve concerning Embodiment 1 of this invention. Sectional drawing of the fuel injection valve which concerns on Embodiment 2 of this invention is shown. It is sectional drawing of the fuel injection valve which concerns on Embodiment 3 of this invention. It is sectional drawing of the fuel injection valve which concerns on Embodiment 4 of this invention. It is sectional drawing of the fuel injection valve which concerns on Embodiment 6 of this invention. It is sectional drawing of the conventional fuel injection valve.

Explanation of symbols

30, 40, 50, 60 Fuel injection valve 2 Solenoid device 3 Housing 4 Core 5 Coil 6 Amateur 6a Amateur side 6b Amateur upper surface 7 Valve device 8, 71 Valve body 9 Valve body 10, 73 Valve seat 10a, 74 Valve seat Sheet part 11, 31, 41, 51, 72 Injection hole plate 11a, 11b Weld part 11c, 31c, 41c, 51c Thin part 11d Tapered surface 11e Virtual circle 12, 70 Injection hole 12a Injection hole wall 12b Inlet part of injection hole Radial inner side 12c Radial outer side of inlet part of nozzle hole 13 Ball 13a Chamfered part 13b Guide 13c Flat part 13d First plane 13e Second plane 13f Groove 14 Compression spring 15 Liquid film 16 Fuel flow 17 Air 18 Crescent liquid Membrane 19 First parallel line 20 Second parallel line 32, 43, 72a Projection 42 Valve seat shaft

Claims (6)

A fuel that has a valve body that opens and closes a valve seat, receives an operation signal from a control device, operates the valve body, and injects fuel from a plurality of nozzle holes provided in a nozzle plate mounted on the downstream side of the valve seat A fuel injection valve comprising the following requirements.
(1) A part of the upstream end face of the nozzle hole plate is recessed to provide a thin portion that extends in the radial direction around the axis of the valve body.
(2) A tapered surface is provided at a portion connecting the thin portion and the nozzle hole plate thickness on the outer peripheral side thereof.
(3) The angle of the tapered surface is made larger than the seat angle of the valve seat so that the virtual conical surface extended to the downstream side of the valve seat portion intersects the tapered surface to form one virtual circle.
(4) The inlet portion of the nozzle hole is arranged so as to cover the virtual circle on the tapered surface.
(5) The outlet part of the nozzle hole is arranged radially outward with respect to the inlet part.
(6) The perpendicular distance h between the valve body tip of the valve body shaft center portion and the thin-walled portion in the valve body opened state has a relationship of h <d with respect to the injection hole inlet diameter d.   2. The fuel injection valve according to claim 1, wherein the thin portion is provided with a protruding portion that protrudes to the downstream side substantially parallel to the distal end portion of the valve body.   The protrusion is substantially axisymmetric with respect to the valve seat axis and has an arcuate cross section, and the welded portion of the valve seat and the nozzle hole plate is substantially axisymmetric with respect to the valve seat axis. The fuel injection valve according to claim 2.   The thin wall portion is a flat surface, and a flat portion substantially parallel to the flat portion is provided at the tip of the valve body, and the outermost diameter thereof is smaller than the inscribed circle of all the injection holes at the injection hole inlet portion. The fuel injection valve according to claim 1.   The fuel injection valve according to any one of claims 1 to 4, wherein the thin portion and the tapered surface are molded by coining.   A ball is attached to the tip of the valve body, and a first plane parallel to the axial center of the valve body and the first plane are orthogonal to the outer peripheral part of the ball, and the axis of the valve body is also the same. 6. The fuel injection valve according to claim 1, wherein a plurality of grooves formed by a second plane parallel to the second plane are provided.

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