Title of the Invention: VALVE DEVICE FOR FUEL INJECTION VALVE
Technical Field
[0001]
The invention relates to a valve device for a fuel injection valve that is used to supply fuel to an internal combustion engine of an automobile. Background Art
[0002]
In recent years, FI (fuel injection) of an internal combustion engine has been promoted, and adoption of a fuel injection valve to two-wheeled vehicles with small displacement has also been increased. The fuel injection valve includes a solenoid device that generates an electromagnetic force and a valve device that is actuated through energization of the solenoid device. The valve device has: a valve seat that is provided in the middle of a passage, through which fuel flows, and that has an opening on a downstream side; a valve body that abuts against or separates from this valve seat so as to control opening/closing of the passage; and an injection hole plate that is provided on a downstream side of the opening of the valve seat.

As a characteristic of fuel spray that is injected from the fuel injection valve, atomization of the spray has been desired, and various types of examination have been made. For example, in a valve device that is suggested in PTL 1, a main flow from center of a valve seat toward entry center of an injection hole provided in an injection hole plate collides with a reverse flow that once moves around an outer circumferential side of the injection hole plate and enters the injection hole, and fuel spray is thereby atomized. In this case, as a fuel speed on an upstream-side end surface of the injection hole plate (hereinafter referred to as an upper surface of the injection hole plate) is increased, turbulence caused by the collision in a section right above the injection hole becomes significant, and atomization of the spray is promoted. Citation List Patent Literature
[0004]
[PTL 1] JP-A-2004-162693 Disclosure of Invention Technical Problem
[0005]
In a case of the fuel injection valve that is suggested in PTL 1, it is arranged such that an imaginary conical surface that is obtained by extending a seat surface of the valve seat

to the downstream side intersects with the upper surface of the injection hole plate. Accordingly, the fuel that has flowed along the seat surface is not collected at an opening that is arranged at a bottom of the seat surface but is divided into a flow that reaches the upper surface of the injection hole plate and is reversed toward the outer circumferential side and a flow that reaches the upper surface of the injection hole plate, once moves in a center direction, collides at the center, and is then reversed toward the outer circumferential side (see Fig. 6).
[0006]
Pressure loss occurs to this flow that collides near the center of the upper surface of the injection hole plate. This leads to such a problem that the fuel speed in the section right above the injection hole is reduced and thus the spray is not sufficiently atomized. In addition, the fuel is not collected at the opening of the valve seat but flows toward each of the injection holes after reaching the upper surface of the injection hole plate . Thus, no process is provided to equalize variations in a flow rate in a circumferential direction that are generated on an upstream side of the seat surface. This leads to such a problem that variations in the fuel speed among the injection holes are increased and thus variations in a particle diameter of the fuel spray are increased.
[0007]

The invention has been made in view of the above problems and therefore has a purpose of providing a valve device for a fuel injection valve capable of atomizing injected fuel spray and suppressing variations in a particle diameter among injection holes. Solution to Problems
[0008]
A valve device for a fuel injection valve according to the invention is a valve device for a fuel injection valve that includes: a valve seat that is provided in the middle of a passage, through which fuel flows; a valve body that abuts against or separates from the valve seat so as to control opening/closing of the passage; and an injection hole plate that is arranged on a downstream side of the valve seat. The valve seat has : a conical seat surface whose diameter is reduced toward the downstream side; and a cylindrical opening that is provided on the downstream side of the seat surface, and is formed with a disc-shaped passage between the valve seat and the injection hole plate, the disc-shaped passage having a larger diameter than that of the opening. The injection hole plate has plural injection holes that are arranged on an outer circumferential side of the opening. An intersection point between a vertex of an imaginary cone, which is obtained by extending the seat surface to the downstream side, and a center axis of the valve seat is located in the opening.

Advantageous Effects of the Invention [0009]
According to the valve device for the fuel injection valve according to the invention/ the intersection point between the vertex of the imaginary cone, which is obtained by extending the seat surface to the downstream side, and the center axis of the valve seat is located in the opening. In this way, most of the fuel that has flowed along the seat surface is collected at the opening, then reaches an upstream-side end surface of the injection hole plate, and is smoothly shifted to become a flow toward the outer circumferential side. Thus, pressure loss of the fuel during this process is suppressed to be small. Therefore, a reduction in a fuel speed in a section right above the injection hole is suppressed, and atomization of fuel spray is promoted. Furthermore, because most of the fuel that has flowed along the seat surface is collected at the opening, variations in a flow rate in a circumferential direction, which are generated on an upstream side of the seat surface, are equalized, and variations in a particle diameter of the fuel spray among the injection holes can be suppressed.
Purposes, features, perspectives, and effects other than the above of the invention will further become apparent from the following detailed description of the invention with reference to the drawings. Brief Description of Drawings

[0010]
Fig. 1 is a cross-sectional view of a configuration of a fuel injection valve according to a first embodiment of the invention.
Fig. 2 is a partial cross-sectional view of a tip of a valve device according to the first embodiment of the invention.
Fig. 3 is a partial cross-sectional view of the tip of the valve device according to the first embodiment of the invention.
Fig. 4 is a partial cross-sectional view of the tip of the valve device according to the first embodiment of the invention.
Fig. 5 is a partial cross-sectional view of the tip of the valve device according to the first embodiment of the invention.
Fig. 6 is a partial cross-sectional view of a tip of a conventional valve device.
Fig. 7 is a partial cross-sectional view of a tip of a valve device according to a second embodiment of the invention.
Fig. 8 is a top view of an injection hole plate of the valve device according to the second embodiment of the invention.
Fig. 9 includes views for illustrating an injection hole twisting angle in the injection hole plate.

Fig. 10 is a graph that depicts a relationship between the injection hole twisting angle and an average spray particle diameter in the injection hole plate.
Fig. 11 is a partial cross-sectional view of a tip of a valve device according to a third embodiment of the invention.
Fig. 12 is a partial cross-sectional view of the tip of the valve device according to the third embodiment of the invention. Description of Embodiments
[0011] First Embodiment
A description will hereinafter be made on a valve device for a fuel injection valve according to a first embodiment of the invention on the basis of the drawings. Fig. 1 is a cross-sectional view in which the fuel injection valve according to this first embodiment is cut along a plane that is parallel to a center axis (indicated as Z in the drawing) , Fig. 2 is a partial cross-sectional view in which a tip of the valve device is cut along the plane that is parallel to the center axis, and Fig. 3 is a partial cross-sectional view in which the tip of the valve device is cut along a plane that is orthogonal to the center axis. Note that the same or a corresponding portion in each of the drawings is denoted by the same reference sign.
[0012]

A fuel injection valve 1 includes a solenoid device that generates an electromagnetic force and a valve device that is actuated through energization of the solenoid device. The solenoid device includes: a two-stepped cylindrical housing
2 that constitutes a yoke portion of a magnetic circuit; a core
3 that is a fixed iron core provided on an inner side of the housing 2; a coil 4 that is provided to surround the core 3; a bobbin 5 that is made of a resin and around which the coil
4 is wound; and a cap 6 that is made of metal and is fixedly welded to a portion of an outer circumference of the housing 2 so as to cover the bobbin 5. The cap 6 has a notched section that serves as an exit of a terminal 7 of an electrode.
[0013]
The valve device includes: a valve seat 11 that is provided in the middle of a passage, through which fuel flows; a valve body 16 that abuts against or separates from the valve seat 11 so as to control opening/closing of the passage; and an injection hole plate 22 that is provided on a downstream side of the valve seat 11. The valve body 16 has: an armature 17 that is a movable iron core provided on an inner side of the coil 4 to reciprocate; a ball 18 that is provided at a tip of the valve body 16 and abuts against or separates from a seat surface 13 of the valve seat 11; and a pipe 19 that connects the armature 17 and the ball 18. Furthermore, the valve device includes: a rod 20 that is fixed to an inner section of the

core 3; a spring 21 that is provided between the valve body 16 and the rod 20; and a holder 24 that comes into contact with an outer circumferential surface of the valve seat 11 and accommodates the valve body 16. [0014]
A detailed description will be made on a structure of a tip of the valve device by using Fig. 2 and Fig. 3. As depicted in Fig. 2, an inner circumferential surface of the valve seat 11 serves as the passage of the fuel and sequentially includes a cylindrical sliding surface 12, the conical seat surface 13, a tapered surface 14, and a cylindrical opening 15 from an upstream side. Note that a center axis of the valve seat 11 is the same as the center axis Z of the fuel injection valve. [0015]
The injection hole plate 22 with plural injection holes 23, from which the fuel is injected, is fixed to a downstream-side end surface of the valve seat 11. The injection holes 23 are arranged on an outer circumferential side of the opening 15 . In addition, the valve seat 11 is formed with a disc-shaped passage 25 whose diameter is larger than the opening 15 at a position between the valve seat 11 and the injection hole plate 22.
[0016]
The ball 18 has: plural (five in an example depicted in Fig. 3) slit surfaces 18a that are parallel to the center axis

2; and a curved surface 18b that comes into line contact with the seat surface 13 of the valve seat 11. The slit surface 18a of the ball 18 forms a flat passage 26 as depicted in Fig. 3 at a position between the slit surface 18a and the sliding surface 12 of the valve seat 11.
[0017]
An operation of the fuel injection valve 1 that is configured as described above will briefly be described. When a current is applied to the coil 4 of the fuel injection valve 1 and the armature 17 is attracted to the core 3 side, the pipe 19 and the ball 18, each of which is integrally structured with the armature 17, move upward against an elastic force of the spring 21. In this way, the curved surface 18b of the ball 18 separates from the seat surface 13 of the valve seat 11, and the passage is thereby formed and is brought into an opened state as depicted in Fig. 2.
[0018]
In the valve device in the opened state, the fuel that is supplied from an upstream side of the ball 18 flows through the flat passage 26 between the slit surface 18a of the ball 18 and the sliding surface 12 of the valve seat 11, reaches the seat surface 13, flows along a seat section 13a, then flows along the tapered surface 14, and flows into the opening 15.
[0019]
On the contrary, when energization of the coil 4 is

stopped, a force that attracts the armature 17 to the core 3 side is no longer generated. Then, the valve body 16 is pressed to the valve seat 11 side by the elastic force of the spring 21. In this way, the curved surface 18b of the ball 18 and the seat surface 13 of the valve seat 11 abut against one another at the seat section 13a. The passage is thereby brought into a closed state, and outflow of the fuel from the opening 15 is inhibited.
[0020]
As depicted in Fig. 2, in regard to the valve seat 11 of the valve device according to this first embodiment, an intersection point 13c between a vertex of an imaginary cone 13b, which is obtained by extending the seat surface 13 to a downstream side, and the center axis Z of the valve seat 11 is located in the opening 15. Accordingly, most of the fuel that has flowed along the seat section 13a is collected at the opening 15, then reaches the vicinity of a central section 22a of an upstream-side end surface of the injection hole plate 22 (hereinafter referred to as an upper surface of the injection hole plate 22) , and is smoothly shifted to become a flow toward the outer circumferential side (an arrow A in the drawing).
[0021]
Pressure loss of a fluid during this process is suppressed when compared to that in a conventional structure (will be described below by using Fig. 6), and a fuel speed

in a section 22b right above the injection hole is maintained in a sufficiently high state. In the section 22b right above the injection hole, a flow from the central section 22a of the injection hole plate 22 toward the injection hole 23 (an arrow B in the drawing) violently collides with a reverse flow that once moves around the outer circumferential side of the injection hole plate 22 and enters the injection hole 23 (an arrow C in the drawing) . In this way, atomization of fuel spray is promoted.
[0022]
The fuel that has flowed through the flat passage 26 generates a flow along the sliding surface 12, is smoothly guided onto the seat surface 13, and generates a flow along the seat surface 13. Furthermore, the passage that is formed by the seat surface 13 and the curved surface 18b of the ball 18 is gradually narrowed toward the downstream side. Thus, the flow along the seat surface 13 smoothly reaches the seat section 13a.
[0023]
From what has been described above, a flow from the downstream side of the seat section 13a toward the opening 15 has high directivity in a direction of the seat surface 13 and reliably reaches the opening 15. Thus, most of the fuel that has flowed along the seat section 13a is collected at the opening 15. Therefore, the atomization thereof is further

promoted.
[0024]
Because most of the high-speed fuel that has flowed along the seat surface 13 is collected at the opening 15, the violent collision of the fuel does not occur on the upper surface of the injection hole plate 22. Thus, the pressure loss in the disc-shaped passage 25 is suppressed. In this way, decompression boiling in a cavity, which occurs when the valve body 16 is opened, is suppressed. Thus, generation of bubbles in the fuel due to the decompression boiling and a change of a flow rate characteristic that is associated with a temperature change or a change of atmosphere are suppressed.
[0025]
As depicted in Fig. 4, the valve seat 11 satisfies a > P when an angle defined by the seat surface 13 with respect to the center axis Z is set as a and an angle defined by the tapered surface 14 with respect to the center axis Z is set as j3. In this way, separation of the fuel at a tapered surface downstream-side end 14a, which leads to the opening 15, is suppressed. Furthermore, it is set such that a - j3 < 20° is satisfied, the separation of the fuel at a seat surface downstream-side end 13d is suppressed. Note that a numerical value of 20° is obtained from an experimental result.
[0026]
Inclination of the tapered surface 14 is set such that

a > p and a - [3 < 20° are satisfied as described above. In this way, angular differences among the seat surface 13, the tapered surface 14, and an inner circumferential surface of the opening 15 are reduced, and the separation of the fuel at a position between two each of the passages is thereby suppressed. Meanwhile, in terms of an injector characteristic, a volume of a cavity that is surrounded by the ball 18, the seat surface 13, and the injection hole plate 22 is desirably small. Thus, an inclination angle of the tapered surface 14 cannot be changed in an unlimited manner.
[0027]
Furthermore, the valve seat 11 satisfies L < M when the shortest distance from the seat section 13a of the seat surface 13 to an upstream-side end of the tapered surface 14 (that is, the seat surface downstream-side end 13d) is set as L and the shortest distance from the upstream-side end of the tapered surface 14 to the opening 15 is set as M.
[0028]
In this way, the pressure loss of the fuel due to friction between the high-speed fuel that has flowed from the seat section 13a and the seat surface 13 is suppressed. The separation of the fuel, which occurs at the tapered surface downstream-side end 14a, is also suppressed. Note that, in order to suppress the pressure loss of the fuel due to the friction, both of L and M are preferably short. In particular,

when compared to the tapered surface 14, the passage on the seat surface 13 is narrow, and the pressure loss of the fuel thereon is significant. Thus, the seat surface 13 is preferably shorter than the tapered surface 14. [0029]
As depicted in Fig. 5, in regard to the valve seat 11, a length of the opening 15 in a parallel direction to the center axis 2 is set as P, a length of the tapered surface 14 in the parallel direction to the center axis Z is set as Q, an inner diameter of the opening 15 is set as R, and an upstream-side opening diameter of the tapered surface 14 is set as S. At this time, distances indicated by X and Y in Fig . 5 are expressed as below.
[0030]
X - (R/2)/tan a
Y = (S/2)/tan a
Thus, the followings are satisfied.
X + Y - ((R + S)/2)/tan a and
P + Q < ((R + S)/2)/ tan a
[0031]
In this way, when the fuel that has flowed along the seat section 13a collides with one another at the opening 15 and is then shifted to flow toward the outer circumferential side, the fuel can smoothly flow into the disc-shaped passage 25

without colliding with the inner circumferential surface of the opening 15. Accordingly, each of the flows that collide with one another at the opening 15 does not collide with the inner circumferential surface of the opening 15, and thus the pressure thereof is not lost. Instead, eachofthe flows passes through the disc-shaped passage 25 while maintaining the high speed thereof, and reaches the upper surface of the injection hole plate 22. Thus, the atomization of the fuel spray is further promoted.
[0032]
In addition, the volume of the cavity can be set small. Thus, such a problem is eliminated that, in the case where the fuel is injected into negative pressure atmosphere, some of the fuel in the cavity is suctioned from the injection hole 23 into an engine intake pipe due to negative pressure after the valve is completely closed, which increases a change in the flow rate. Such a problem is also eliminated that, due to the low flow rate of the fuel that is suctioned from the cavity, the fuel spray having an increased particle diameter is injected.
[0033]
As a* comparative example of the valve device according to this first embodiment, a structure of a tip of the conventional valve device is depicted in Fig. 6. Also in the conventional valve device, a main flow from a central section

of an upper surface of an injection hole plate 220 toward a section right above an injection hole 230 (an arrow B in the drawing) collides with a reverse flow that once moves around an outer circumferential side of the injection hole plate 220 and enters an injection hole 230 (an arrow C in the drawing) , and the fuel spray is thereby atomized.
[0034]
However, in the case of the conventional valve device, an intersection point 130c between an imaginary cone 130b, which is obtained by extending a seat surface 130 of a valve seat 110 to the downstream side, and the center axis Z of the valve seat 110 is not located in an opening 150 but is located on a downstream side of the injection hole plate 220. The imaginary cone 130b intersects with the upper surface of the injection hole plate 220.
[0035]
In such a case, the fuel that has flowed along the seat surface 130 reaches the upper surface of the injection hole plate 220 without being collected at the opening 150, and is divided into a flow that is reversed toward the outer circumferential side of the injection hole plate 220 (an arrow D in the drawing) and a flow that reaches the upper surface of the injection hole plate 220, moves in a central direction, collides with one another in a center section, and is then reversed toward the outer circumferential side (an arrow E in

the drawing).
[0036]
The pressure loss occurs to each of the flows that collide with one another in the center section of this injection hole plate 220, and a fuel speed in the section right above the injection hole 230 is reduced. Thus, the fuel spray is not sufficiently atomized. In addition, the fuel is not collected at the opening 150 but flows toward each of the injection holes 230 after reaching the upper surface of the injection hole plate 220 , Thus, a process of equalizing variations in the flow rate in a circumferential direction that are generated on an upstream side of a seat section is not provided. As a result, variations in the fuel speed among the injection holes 230 are increased, and variations in the particle diameter of the fuel spray are increased.
[0037]
As it has been described so far, according to the valve device for the fuel injection valve according to this first embodiment, the intersection point 13c between the vertex of the imaginary cone 13b, which is obtained by extending the seat surface 13 to the downstream side, and the center axis Z of the valve seat 11 is located in the opening 15. Accordingly, most of the fuel that has flowed along the seat section 13a is collected at the opening 15, then reaches the upper surface of the injection hole plate 22, and is smoothly shifted to

become the flow toward the outer circumferential side. Thus, the pressure loss of the fuel during this process is suppressed to be small.
[0038]
For this reason, a reduction in the fuel speed in the section 22b right above the injection hole is suppressed, and the flows violently collide with one another in the sufficiently high-speed states. Therefore, the atomization of the fuel spray is promoted. In addition, most of the fuel that has flowed along the seat surface 13 is collected at the opening 15. Thus, the variations in the flow rate in the circumferential direction, which are generated on the upstream side of the seat surface 13, are equalized, and the variations in the particle diameter of the fuel spray among the injection holes 23 can be suppressed.
[0039]
Furthermore, the tapered surface 14 is provided on the downstream side of the seat surface 13. In this way, the separation of the fuel that occurs at the seat surface downstream-side end 13d and the tapered surface downstream-side end 14a is suppressed, and the friction of the fuel on the seat surface 13 is reduced. Thus, the pressure loss of the fuel is suppressed, and an effect of the atomization is further promoted.
[0040]

Second Embodiment
Fig. 7 is a partial cross-sectional view in which a tip of a valve device according to a second embodiment of the invention is cut along a plane that is parallel to a center axis, and Fig. 8 is a top view of an injection hole plate that is seen from a side indicated by A-A in the valve device depicted in Fig. 7. Note that, because an overall configuration of a fuel injection valve according to this second embodiment is the same as that of the above first embodiment, Fig. 1 is used, and a detailed description of each portion thereof will not be made.
[0041]
The valve device according to this second embodiment
satisfies 20° < y < 70° when an angle (hereinafter referred to as an injection hole twisting angle) defined by a straight line (LI in Fig. 8) and a straight line (L2 in Fig. 8) is set as
Y, the straight line (Ll in Fig. 8) connecting the center axis Z and entry center 23a of the injection hole 23 and the straight line (L2 in Fig. 8) connecting the entry center 23a of the injection hole 23 and exit center 23b of the injection hole 23 in the case where the injection hole 23 is projected vertically on a plane that is orthogonal to the center axis Z .
[0042]
As depicted in Fig. 7, the injection hole 23 has an

injection hole angle 0 that is defined as an inclination angle of a center axis that connects the entry center 23a and the exit center 23b with respect to a thickness direction of the injection hole plate 22. Accordingly, in the case where an injection hole diameter is set as d when the injection hole 23 is projected on the plane that is orthogonal to the center axis Z, an ellipse with a short diameter d and long diameter
d/cos 8 is formed. [0043] A description will be made on an effect of setting the
injection hole twisting angle y as 20° < y < 70° in this second embodiment by using Fig. 9 and Fig. 10. In Fig. 9, (A) depicts
the injection hole where y = 0°, (B) depicts the injection hole where 20° < y < 70°, and (C) depicts the injection hole where y= 90°. When a single fuel spray is generated, the conventional general injection hole 23 has y = 0° as depicted in (A). In addition, when the injection hole 23 is projected on the plane that is orthogonal to the center axis Z, the conventional general injection hole 23 is formed such that the center axis Z and the entry center 23a and the exit center 2 3b of the injection hole 23 align on the same straight line.
[0044]
Meanwhile, the injection hole 23 of the injection hole plate 22 according to this second embodiment satisfies 20° < y < 70° as depicted in (B) . Due to 20° < y, length of a wet edge

of the injection hole 23, from which the main flow of the fuel enters, is further increased, and many components of the main flow at the high fuel speed can collide with one another in the section right above the injection hole. Thus, the atomization of the fuel spray is promoted.
[0045]
In addition, when y > 70° is set like the injection hole depicted in (C) where y = 90°, the fuel collides with one another in the section right above the injection hole and obtains energy of turbulence. A flow of such fuel is then abruptly bent in the injection hole 23, and energy loss occurs. As a result, the atomization is degraded. In order to suppress such a phenomenon, y < 70° is set in this second embodiment.
[0046]
Fig. 10 depicts a relationship between the injection hole twisting angle y and an average spray particle diameter, a horizontal axis indicates the injection hole twisting angle
y(°), and a vertical axis indicates the average spray particle diameter (vim). As depicted in Fig. 10, the average spray particle diameter becomes at most equal to 60 urn when the
injection hole twisting angle y is 20° < y < 70° and thus obtains a favorable atomization characteristic when compared to cases
where y < 20° and y > 70°. [0047] According to this second embodiment, in addition to the

similar effect to the above first embodiment, the atomization of the fuel spray is further promoted by setting the injection hole twisting angle y to satisfy 20° < y < 70°. In addition, the injection hole twisting angles y of an injection hole group arranged in the injection hole plate 22 are set to be the same. Thus, homogeneity of the fuel spray that is injected from each of the injection holes 23 is increased. Therefore, combustibleness is improved, and a consumed fuel amount is reduced.
[0048] Third Embodiment
Fig. 11 is a partial cross-sectional view in which a tip of a valve device according to a third embodiment of the invention is cut in a parallel direction to a center axis, and Fig. 12 is a partial cross-sectional view in which the tip of the valve device depicted in Fig. 11 is cut along a portion indicated by A-A. Note that, in order to depict a shape of the ball 18 and a positional relationship among the injection holes 23, the injection holes 23 of the injection hole plate 22 are depicted in a manner to be projected on the ball 18 in Fig. 12. Because an overall configuration of a fuel injection valve according to this third embodiment is the same as the above first embodiment, Fig. 1 is used, and a detailed description of each portion thereof will not be made.
[0049]

In the valve device according to this third embodiment, the number of the injection holes 23 differs from the number of the slit surfaces 18a. The five slit surfaces 18a of the ball 18 are formed at equally spaced intervals on a circumference of the valve body 16. Meanwhile, the eight injection holes 23 are concentrically arranged at equally spaced intervals in the injection hole plate 22, and the number of the injection holes 23 is larger than the number of the slit surfaces 18a.
[0050]
In such a case, for example, the fuel that has flowed out of a slit surface 18a-l and a slit surface 18a-2 mainly flows into an injection hole 23-1 and an injection hole 23-2, which are depicted in Fig. 12. However, because relative positions of each of the injection hole 23-1 and the injection hole 23-2 to the slit surface 18a-l and the slit surface 18a-2 differ, it is concerned that the speeds of the fuel that flows into the injection holes 23-1, 23-2 differ from each other.
[0051]
However, in the valve device according to this third embodiment, similar to the above first embodiment (see Fig. 2), most of the fuel that has flowed along the seat section 13a is collected at the opening 15, then reaches the vicinity of the central section 22a of the upper surface of the injection hole plate 22, and is shifted to become the flow toward the

25 / 30

637854IN01

outer circumferential side. Accordingly/ after the variations in the flow rate in the circumferential direction, which are generated on the upstream side of the seat surface 13, are equalized, the fuel flows toward each of the injection holes 23.
[0052]
From what has been described so far, according to this third embodiment, even when the number of the injection holes 23 differs from the number of the slit surfaces 18a, the variations in the speed of the fuel that flows into each of the injection holes 23 are suppressed, and variations in the particle diameter of the spray among the injection holes 23 are suppressed. Note that each of the embodiments of the invention can freely be combined and each of the embodiments can appropriately be modified or omitted within the scope of the invention.

CLAIMS [Claim 1]
A valve device for a fuel injection valve that includes: a valve seat that is provided in the middle of a passage, through which fuel flows; a valve body that abuts against or separates from the valve seat so as to control opening/closing of the passage; and an injection hole plate that is arranged on a downstream side of the valve seat, the valve device for the fuel injection valve characterized in that
the valve seat has: a conical seat surface whose diameter is reduced toward the downstream side; and a cylindrical opening that is provided on the downstream side of the seat surface, and is formed with a disc-shaped passage between the valve seat and the injection hole plate, the disc-shaped passage having a larger diameter than that of the opening,
the injection hole plate has plural injection holes that are arranged on an outer circumferential side of the opening, and
an intersection point between a vertex of an imaginary cone, which is obtained by extending the seat surface to the downstream side, and a center axis of the valve seat is located in the opening. [Claim 2]
The valve device for the fuel injection valve according to claim 1 characterized in that

the valve seat has a cylindrical sliding surface, which is coaxial with the center axis, on an upstream side of the seat surface,
the valve body has a ball at a tip that abuts against the seat surface, and
the ball has plural slit surfaces between the ball and the sliding surface so as to form passages for the fuel. [Claim 3]
The valve device for the fuel injection valve according to claim 2 characterized in that
the number of the injection holes differs from the number of the slit surfaces. [Claim 4]
The valve device for the fuel injection valve according to any one of claim 1 to claim 3 characterized in that
the valve seat has a tapered surface between the seat surface and the opening, and
when an angle defined by the seat surface with respect to the center axis is set as a and an angle defined by the tapered surface with respect to the center axis is set as (3, the valve seat satisfies a > {3. [Claim 5]
The valve device for the fuel injection valve according to claim 4 characterized in that
when the angle defined by the seat surface with respect

to the center axis is set as a and the angle defined by the tapered surface with respect to the center axis is set as (3, the valve seat satisfies a - P < 20°. [Claim 6]
The valve device for the fuel injection valve according to claim 4 or claim 5 characterized in that
when length of the opening in a parallel direction to the center axis is set as P, length of the tapered surface in the parallel direction to the center axis is set as Q, an inner diameter of the opening is set as R, and an upstream-side opening diameter of the tapered surface is set as S, the valve seat satisfies P + Q < ((R + S)/2)/tan a. [Claim 7]
The valve device for the fuel injection valve according to any one of claim 4 to claim 6 characterized in that
when the shortest distance from a seat section in the seat surface, against which the valve body abuts, to an upstream-side end of the tapered surface is set as L, and the shortest distance from the upstream-side end of the tapered surface to the opening is set as M, the valve seat satisfies L < M. [Claim 8}
The valve device for the fuel injection valve according to any one of claim 1 to claim 7 characterized in that
in the case where an angle defined by a straight line

that connects the center axis and entry center of the arbitrary injection hole and a straight line that connects the entry center and exit center of the injection hole is set as y when the injection hole is vertically projected on a plane that is orthogonal to the center axis, 20°< y < 70° is satisfied.