JPH084630A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To decrease stress concentration caused by fuel pressure to valve seat part. CONSTITUTION:A taper part whose vertical angle is smaller than the vertical angle of a taper part 8c formed on the outer periphery of a needle valve seat 8 is provided on a transfer part from an inner peripheral end of the tip B side in a cooling water chamber 6 to the inner peripheral end on the base part A side of a small diameter part 2b in a through hole, so that the taper part 8c formed on the outer periphery may be housed, and the maximum outside diameter part of the taper part 8c of the needle valve seat 8 is brought into contact with the maximum inside diameter part of the taper part of the through hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve mainly used in a diesel engine.

[0002]

2. Description of the Related Art FIG. 3 is a longitudinal sectional view of a conventional fuel injection valve used in a diesel engine, and FIG. 4 is an enlarged view of a needle valve seat fitting portion of FIG.

Reference numeral 1 denotes a fuel injection valve main body, and the fuel injection valve main body 1 has the fuel injection valve main body 1 from the base portion A side to the tip portion B.
A through hole 2 penetrating to the side is provided. Thus, a portion of the through hole 2 from the base portion A side to the vicinity of the tip portion B side becomes a large diameter portion 2a having an inner diameter larger than that of the portion from the vicinity of the tip portion B side to the tip portion B side. A portion from the vicinity of the base portion A side to the tip portion B side is a small diameter portion 2b having an inner diameter smaller than that of the large diameter portion 2a, and a step is formed at a transition portion of the through hole 2 from the large diameter portion 2a to the small diameter portion 2b. The part 3 is formed.

Further, in the fuel injection valve main body 1, the through hole 2 is located slightly closer to the step portion 3 side than the middle of the large diameter portion 2a of the through hole 2 in the longitudinal direction.
An annular fuel oil supply chamber 4 provided so as to communicate with the large diameter portion 2a of the through hole 2 and to surround the large diameter portion 2a of the through hole 2;
Side to the front end portion B side substantially parallel to the through hole 2 and the front end portion B side communicating with the fuel oil supply chamber 4, and the front end portion B side surface is the stepped portion 3 Along the surface of the through hole 2 and communicating with the large diameter portion 2a of the through hole 2 and the large diameter portion 2 of the through hole 2
An annular cooling water chamber 6 provided so as to surround a and a cooling water supply passage 7 extending downward in parallel with the through hole 2 from the base A side and communicating with the cooling water chamber 6. I have it.

On the tip B side of the fuel oil supply chamber 4 of the through hole 2 of the fuel injection valve main body 1, the base is located inside the large diameter portion 2a of the through hole 2 and the tip is the small diameter portion 2b of the through hole 2. The needle valve seat 8 that penetrates and projects outward of the tip of the fuel injection valve body 1 is shrink-fitted (or cold-fitted). The needle valve seat 8 is provided with a bottomed hollow portion 9 having an open upper portion at the axial center thereof and is formed in a substantially U-shaped vertical cross section, and is fitted into the large diameter portion 2a of the through hole 2. Small diameter portion 8a that fits into the large diameter portion 8a and the small diameter portion 2b of the through hole 2.
b.

The hollow portion 9 has a large diameter portion 9a having a larger inner diameter than the tip portion B side on the base portion A side, and a large diameter portion 9 on the tip portion B side.
A small diameter portion 9b having an inner diameter smaller than a is formed, and a tapered portion 9c having a smaller hole diameter is formed from the large diameter portion 9a to the small diameter portion 9b on the inner circumference of the transition portion from the large diameter portion 9a to the small diameter portion 9b. The sloped surface of the tapered portion 9c is the needle valve seat 10.

Further, at a portion of the needle valve seat 8 projecting from the tip of the fuel injection valve body 1 toward the tip B, a small diameter of the needle valve seat 8 is provided so that the fuel oil a introduced into the hollow portion 9 is injected into the combustion chamber. The plurality of fuel injection holes 1 are inclined downward from the portion 9b toward the outside.
1 is radially drilled, and the step portion 12 formed at the transition portion from the large diameter portion 8a to the small diameter portion 8b of the needle valve seat 8 is brought into contact with the step portion 3 of the through hole 2 to inject fuel. The needle valve seat 8 can be positioned with respect to the valve body 1, and the inner surface of the cooling water chamber 6 can be formed by the outer peripheral surface of the large diameter portion 8a.

A cylindrical needle valve bush 13 is shrink-fitted or cold-fitted on the large-diameter portion 2a of the through hole 2 of the fuel injection valve body 1 from the fuel oil supply chamber 4 toward the base portion A side. A needle valve 14 is slidably inserted in the bush 13.
Thus, the needle valve 14 has a large diameter portion 14a fitted to the needle valve bush 13 and the tapered needle valve seat 10 of the needle valve seat 8.
A small diameter portion 14b having an outer diameter smaller than that of the large diameter portion 14a and a large diameter portion 14a and a small diameter portion. The fuel oil supply chamber 4 of the large diameter portion 14a is provided with the tapered portion 14c formed between the large diameter portion 14a and the small diameter portion 14b so that the diameter gradually decreases.
End surface 16 and taper portion 14 formed in the step portion facing the
The outer circumference of c is a pressure receiving surface on which the hydraulic pressure that presses the needle valve 14 upward acts.

The needle valve 14 is biased toward the needle valve seat 8 by a coil spring 17 arranged on the base A side of the needle valve 14, and the tip end of the needle valve seat 8 with respect to the needle valve seat 10 is tapered. 15 is pressure-contacted to the fuel oil supply passage 5 so as to block the flow of the fuel oil a supplied from the fuel oil supply chamber 5 through the fuel oil supply chamber 4.

Next, the operation will be described.

When the fuel oil a is supplied from the fuel oil supply passage 5 through the fuel oil supply chamber 4 to the hollow portion 9 of the needle valve seat 8, the pressure of the fuel oil a is the end surface of the large diameter portion 14a of the needle valve 14. 16
When the pressing force exceeds the biasing force of the coil spring 17 and acts on the outer peripheral surface of the tapered portion 14c to push the needle valve 14 toward the base portion A side, the needle valve 14 is pushed up toward the base portion A side of the fuel injection valve body 1. Therefore, a gap is created between the tapered portion 15 formed at the tip of the needle valve 14 and the needle valve seat 10 of the needle valve seat 8,
The fuel oil a that has passed through the gap is the fuel injection hole 1 at the tip of the needle valve seat 8.
It jets from 1 toward a combustion chamber (not shown).

At the time of fuel oil injection, the needle valve seat 8 is pressed downward by the oil pressure acting on the upper end surface and the bottom portion of the hollow portion 9 having a small diameter as well as the needle valve seat 10, but through the step portion 12. Since it is supported by the step portion 3 of the fuel injection valve body 1, the needle valve seat 8 does not move in the axial direction due to the hydraulic pressure.

The large-diameter portion 8a of the needle valve seat 8 is shrink-fitted or cold-fitted into the large-diameter portion 2a of the through hole 2, and the small-diameter portion 8b of the needle valve seat 8 is fitted.
Is shrink-fitted or cold-fitted into the small diameter portion 2b of the through hole 2, and the needle valve bush 13 is shrink-fitted or cold-fitted into the large diameter portion 2a of the through hole 2, so that the fuel oil a and the cooling water b The combustion gas generated in the combustion chamber is reliably sealed.

When the fuel oil a is no longer supplied to the fuel oil supply passage 5, the pressure in the fuel oil supply passage 5, the fuel oil supply chamber 4, and the hollow portion 9 of the needle valve seat 8 decreases, so that the coil spring 17 is provided.
Thus, the needle valve 14 is biased toward the tip portion B side, and the tapered portion 15 formed at the tip of the needle valve 14 contacts the needle valve seat 10 of the needle valve seat 8. Therefore, the injection of the fuel oil a is stopped.

Further, when the fuel oil a is injected, the cooling water b supplied from the cooling water supply passage 7 to the cooling water chamber 6 is the needle valve seat 8 and the fuel heated by the heat generated in the combustion chamber. While cooling the injection valve body 1, the injection valve body 1 is discharged to a cooling water circulation passage (not shown).

[0016]

In the above fuel injection valve, when the oil pressure resulting from the fuel oil injection acts on the inner surface of the hollow portion 9 of the needle valve seat 8 during fuel injection, the large diameter portion of the needle valve seat 8 is applied. The portion of 8a that defines the cooling water chamber 6 expands radially outward due to hydraulic pressure, and a stress is generated in the needle valve seat 8 toward the center side in the radial direction. However, the corner portion 1 of the step portion 12 formed at the transition portion of the needle valve seat 8 from the large diameter portion 8a to the small diameter portion 8b.
Since 2a is formed at a right angle and the outer diameter changes rapidly, stress concentration occurs at the corner 12a during fuel oil injection, and therefore the needle valve seat 8 is directed from the corner 12a toward the radial center. There is a problem that damage such as cracking may occur.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel injection valve in which stress concentration generated in a transition portion of the needle valve seat 8 from the large diameter portion 8a to the small diameter portion 8b is reduced. It is a thing.

[0018]

According to the present invention, there is provided a fuel injection valve main body 1 in which a through hole 2 having a large diameter on the base portion A side and a small diameter on the distal end portion B side is penetrated from the base portion A toward the distal end portion B.
And the large diameter portion 2 of the through hole 2 formed in the fuel injection valve body 1.
The small diameter portion 8b is slidably fitted to the needle valve a, and the small diameter portion 8b is fitted and fixed to the small diameter portion 2b of the through hole 2 and the large diameter portion 8a connected to the small diameter portion 8b has a large diameter portion 8a. Fit to the diameter part 2a,
The needle valve seat 8 is fixed and the tip of the small diameter portion 8b projects outward from the small diameter portion 2b of the through hole 2 toward the tip portion B side. A fuel oil supply chamber 4 capable of introducing oil a is provided so as to communicate with the large diameter portion 2a of the through hole 2 and surround the needle valve 14, and to supply the fuel oil to the fuel injection valve body 1. A cooling fluid chamber 6 capable of introducing the cooling fluid b is located on the needle valve seat 8 side of the fuel oil supply chamber 4 in the middle of the chamber 4 in the longitudinal direction and has a large diameter portion of the through hole 2. 2a is provided so as to surround the large diameter portion 8a of the needle valve seat 8 and a tapered portion 14c having a smaller diameter toward the needle valve seat 8 is provided at the tip end portion of the needle valve 14 on the needle valve seat 8 side. Needle valve seat 8 of needle valve 14 formed
An elastic body 17 for urging the needle valve 14 toward the needle valve seat 8 is provided at an end portion on the side opposite to the side, and the fuel oil supply is provided at an intermediate portion in the longitudinal direction of the needle valve 14. The end face 1 is directed toward the fuel oil supply chamber 4 so that the needle valve 14 can receive a force in a direction of separating from the needle valve seat 8 by the pressure of the fuel oil a introduced into the chamber 4.
6, the needle valve seat 8 is provided with a hollow portion 9 into which the tip of the needle valve 14 is inserted and the tip end side is closed, and the needle valve seat 8 tip portion B at the inner circumference of the hollow portion 9 in the longitudinal direction. A tapered needle valve seat 10 which is formed so as to have a smaller diameter toward the side so that the tapered portion 15 at the tip of the needle valve 14 can be seated.
And a fuel injection valve provided with a fuel injection hole 11 for injecting the fuel oil a supplied from the fuel oil supply chamber 4 into the hollow portion 9 toward the tip portion B side of the fuel injection valve main body 1 outward. In the outer periphery of the transition portion of the needle valve seat 8 from the large diameter portion 8a to the small diameter portion 8b, a taper portion 8c having a smaller diameter from the base portion A side toward the tip portion B side is provided, and the fuel injection valve main body 1 is provided. From the inner peripheral end portion of the provided cooling fluid chamber 6 on the side of the front end portion B to the through hole 2 small diameter portion 2
At the transition portion of b toward the inner peripheral end on the base A side, the apex angle θ2 is smaller than the apex angle θ1 of the taper portion 8c formed on the outer periphery of the needle valve seat 8 and the taper formed on the outer periphery of the needle valve seat 8 is formed. The small diameter portion 2 of the through hole 2 from the cooling fluid chamber 6 side so that the portion 8c is housed.
The tapered through hole 2c is formed so as to become smaller in diameter toward b and to be connected to the small diameter portion 2b of the through hole 2, and the tapered portion 8 of the needle valve seat 8 is provided.
The outer peripheral edge portion of the maximum outer diameter portion of c is brought into contact with the inner peripheral edge portion of the maximum inner diameter portion of the tapered through hole 2c.

Further, according to the present invention, the tapered portion 8c formed on the outer circumference of the needle valve seat 8 and the tapered through hole 2c are used as a starting point, and the tapered portion 8c on the outer circumference of the needle valve seat 8 and the tapered through hole are formed. The angle α of the gap G formed with the 2c is 0 ° ≦ α <90 °, and the angle γ outside the tapered through hole 2c is 90 ° with reference to a line orthogonal to the axis of the through hole 2c. <Γ <180 ° may be used.

[0020]

When fuel oil a is supplied to the fuel oil supply chamber 4 during fuel oil injection, oil pressure acts on the end face 16 of the needle valve 14,
The needle valve 14 overcomes the resistance of the repellent body 17 and moves to the base portion A side. Therefore, a gap is formed between the tapered portion 15 at the tip of the needle valve 14 and the needle valve seat 10 of the needle valve seat 8, and the fuel oil a introduced into the fuel oil supply chamber 4 is hollow in the needle valve seat 8. It is injected from the portion 9 through the fuel injection hole 11 into the combustion chamber. At this time, the cooling fluid b is supplied to the cooling fluid chamber 6 to cool the needle valve seat 8 and the tip B side of the fuel injection valve body 1.

The large-diameter portion 8a of the needle valve seat 8 is pressed by the pressure of the fuel oil a and expands radially outward toward the cooling fluid chamber 6 side. Since the outer peripheral edge portion of the maximum outer diameter portion and the inner peripheral edge portion of the maximum inner diameter portion of the tapered through hole 2c are in contact with each other and the outer diameter of the needle valve seat 8 changes gradually, stress is applied to the contact portion X. Concentration does not occur, and therefore the needle valve seat does not suffer damage such as cracks.

Similarly, when the angle α is 0 ° ≦ α <90 ° and the angle γ is 90 ° <γ <180 °, the outer peripheral portion of the maximum outer diameter portion of the taper portion 8c on the outer periphery of the needle valve seat 8 is similarly formed. Since the inner peripheral edge portion of the maximum inner diameter portion of the through hole 2 abuts and the outer diameter of the needle valve seat 8 changes gradually, stress concentration does not occur at the abutting portion X and therefore the needle valve seat 8 is damaged. Does not occur.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view showing an outline of an embodiment of a fuel injection valve of the present invention used for a diesel engine, and FIG. 2 is an enlarged view of a fitting portion of a needle valve seat of FIG. Since the basic structure of the fuel injection valve of this embodiment is substantially the same as the conventional structure shown in FIG. 3, the same parts as those shown in FIGS. 3 and 4 are designated by the same reference numerals. The description is omitted.

In the present embodiment, at the transition portion of the through hole 2 from the large diameter portion 2a side to the small diameter portion 2b, the end portion on the large diameter portion 2a side is continuous with the large diameter portion 2a and the end portion on the small diameter portion 2b side. The tapered portion 2c is formed so that the portion is continuous with the small diameter portion 2b and the diameter gradually decreases from the large diameter portion 2a side toward the small diameter portion 2b side.

Further, from the large diameter portion 8a to the small diameter portion 8b of the needle valve seat 8.
A taper portion 8c is formed on the outer circumference of the transition portion to connect the large diameter portion 8a and the small diameter portion 8b so that the diameter gradually decreases from the large diameter portion 8a side toward the small diameter portion 8b side.

Further, the apex angle θ1 of the taper portion 8c of the needle valve seat 8 is smaller than the apex angle θ2 of the taper portion 2c of the through hole 2, and the taper portion 8c of the needle valve seat 8 has an outer peripheral edge of the maximum outer diameter portion. The tapered portion 2c of the through hole 2 is fitted into the tapered portion 2c of the through hole 2 so that the portion abuts on the inner peripheral edge portion of the maximum inner diameter portion of the tapered portion 2c of the through hole 2 (outer contact portion X). In between
A gap G is formed which gradually expands from the large diameter portion 8a side of the needle valve seat 8 toward the small diameter portion 8b side of the outer contact portion X as a reference. The gap G is provided so that the taper portion 8c of the needle valve seat 8 and the taper portion 2c of the through hole 2 serve as an outer contact.

The relative relationship between the inclination angles of the tapered portion 2c of the through hole 2 and the tapered portion 8c of the needle valve seat 8 is as shown in FIG. The angle of the gap G that expands with the outer contact portion X with the taper portion 8c of the needle valve seat 8 as a reference is α (= 1/2 (θ1-θ2)), and the line orthogonal to the axis of the through hole 2 is a reference. If the angle outside the tapered portion 2c of the through hole 2 is γ (= 90 ° −θ2),

## EQU1 ## α and γ are determined so that the relations of 0 ° ≦ α <90 ° and 90 ° <γ <180 ° are established.

The needle valve seat 8 is connected to the through hole 2 of the fuel injection valve body 1.
Of the needle valve seat 8 from the large diameter portion 8a to the taper portion 8c when it is inserted into the base A side of the fuel oil supply chamber 4 and shrink-fitted or cold-fitted.
The needle for the fuel injection valve body 1 is made by bringing the outer peripheral edge portion of the fuel injection valve body 1 into contact with the inner peripheral edge portion of the through hole 2 of the fuel injection valve body 1 that transitions from the cooling water chamber 6 to the tapered portion 2c. Positioning of the valve seat 8 in the axial direction is performed.

In the figure, reference numeral 18 denotes a relief allowance of the blade when the needle valve seat 8 is processed.

Next, the operation of the fuel injection valve shown in this embodiment will be described.

When the fuel oil a is supplied from the fuel oil supply passage 5 through the fuel oil supply chamber 4 to the hollow portion 9 of the needle valve seat 8, the pressure of the fuel oil a is the tip of the large diameter portion 14a of the needle valve 14. Part B
When the needle valve 14 is pressed toward the base portion A side by acting on the side end surface 16 and the outer peripheral surface of the taper portion 14c and the pressing force exceeds the biasing force of the coil spring 17, the needle valve 14 moves toward the base portion A side of the fuel injection valve body 1. Pushed up. Therefore, the fuel oil a passes through the gap formed between the needle valve 14 and the needle valve seat 8 and is injected into the combustion chamber from the fuel injection hole 11, and at the same time, is cooled from the cooling water supply passage 7 to the cooling water chamber 6. The water b is supplied to cool the needle valve seat 8 and the tip portion B side of the fuel injection valve main body 1 and is discharged to a cooling water circulation passage (not shown).

At the time of fuel oil injection, the needle valve seat 8 is provided with the needle valve seat 1
Although it is pressed downward by the hydraulic pressure acting on the bottom of the hollow portion 9 having a diameter of 0 and a small diameter, the outer peripheral edge portion of the tapered portion of the needle valve seat 8 at the outer contact portion X is the inner peripheral edge portion of the tapered portion 2c of the through hole 2. Is supported in line contact with the needle valve seat 8 due to hydraulic pressure.
Does not move in the axial direction.

At the time of fuel injection, as in the conventional case,
The portion of the large diameter portion 8a of the needle valve seat 8 that defines the cooling water chamber 6 expands radially outward due to hydraulic pressure, and stress is generated in the needle valve seat 8. However, since the stepped portion 12 from the large diameter portion 8a of the needle valve seat 8 to the small diameter portion 8b is provided with the taper portion 8c so that the change of the outer diameter becomes gentle, Since stress concentration does not occur at the transitional portion of the small diameter portion 8b, the stress generated at the contact portion can be reduced.

Although the fuel injection valve applied to the diesel engine has been described in the embodiments of the present invention, the present invention is not limited to the diesel engine and various modifications can be made without departing from the scope of the present invention. Of course.

[0036]

According to the fuel injection valve of the present invention, the needle valve seat 8
Of the small diameter portion 8a from the large diameter portion 8a to the small diameter portion 8b.
Since the taper portion 8c is formed so as to have a small diameter toward b, the change in the outer diameter of the needle valve seat 8 from the large diameter portion 8a to the small diameter portion 8b becomes gradual and stress concentration can be relieved. In the above, the stress resulting from the fuel injection pressure acting on the needle valve seat 8 can be reduced, the damage of the needle valve seat 8 can be prevented, and the reliability of the needle valve seat 8 can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view schematically showing an embodiment of a fuel injection valve of the present invention.

FIG. 2 is an enlarged view of a fitting portion of a needle valve seat in FIG.

FIG. 3 is a vertical sectional view showing an outline of an example of a conventional fuel injection valve.

FIG. 4 is an enlarged view of a fitting portion of the needle valve seat in FIG.

[Explanation of symbols]

 1 Fuel injection valve body 2 Through hole 2a Large diameter part 2b Small diameter part 2c Tapered part (tapered through hole) 4 Fuel oil supply chamber 6 Cooling water chamber (cooling fluid chamber) 8 Needle seat 8a Large diameter part 8b Small diameter part 8c Tapered part 9 Hollow part 10 Needle valve seat 11 Fuel injection hole 14 Needle valve 16 End face 17 Coil spring (repellent body) a Fuel oil b Cooling water (cooling fluid) G Gap A Base part B Tip part X Outer contact part (contact) Part) α angle of the gap G γ angle of the outside of the through hole 2c θ1, θ2 apex angle

Claims (2)

[Claims] 1. A fuel injection valve in which a through hole (2) having a large diameter on the base (A) side and a small diameter on the tip (B) side is penetrated from the base (A) toward the tip (B). Body (1)
And a needle valve (14) slidably fitted in a large diameter portion (2a) of a through hole (2) formed in the fuel injection valve body (1).
And the small diameter portion (8b) is the small diameter portion (2b) of the through hole (2).
The large diameter portion (8a) that is fitted and fixed to the small diameter portion (8b) and is continuous with the small diameter portion (8b) is fitted and fixed to the large diameter portion (2a) of the through hole (2), and the tip of the small diameter portion (8b) is through the through hole. Small diameter part of (2) (2
b) is provided with a needle valve seat (8) projecting outward from the tip (B) side, and fuel oil (a) is provided in the needle valve (14) longitudinal midway portion of the fuel injection valve body (1). A fuel oil supply chamber (4) adapted to be introduced is provided so as to communicate with the large diameter portion (2a) of the through hole (2) and surround the needle valve (14). A cooling fluid chamber (6) capable of introducing the cooling fluid (b) is provided at a midway portion in the longitudinal direction of the needle valve (14) of (1) rather than the fuel oil supply chamber (4). 8) side and a large diameter portion (2a) of the through hole (2)
The needle valve seat (8) is provided so as to surround the large diameter portion (8a) of the needle valve seat (8). A taper portion (14c) having a small diameter is formed toward the needle valve (14) side at the end opposite to the needle valve seat (8) side of the needle valve (14). An elastic repellent body (17) for urging the needle valve (14) is provided, and a pressure of the fuel oil (a) introduced into the fuel oil supply chamber (4) is provided at a middle portion in the longitudinal direction of the needle valve (14). Needle valve (1
The end surface (16) is provided toward the fuel oil supply chamber (4) so that the force (4) can be applied to the needle valve seat (8) in a direction of separating from the needle valve seat (8). ), The hollow portion (9) having the distal end inserted and the distal end side closed, and the hollow portion (9)
The needle valve seat (8) is formed so as to have a smaller diameter toward the tip (B) side in the inner periphery of the longitudinal direction of the needle valve (14), and the taper portion (15) at the tip of the needle valve (14) can be seated. The needle valve seat (10) having a tapered shape and the fuel oil a supplied from the fuel oil supply chamber (4) into the hollow portion (9) are directed to the tip (B) side of the fuel injection valve body (1). In a fuel injection valve provided with a fuel injection hole (11) for injecting outward, a large diameter portion (8a) to a small diameter portion (8b) of the needle valve seat (8).
A cooling fluid chamber (6) provided in the fuel injection valve body (1) is provided with a taper portion (8c) having a smaller diameter from the base portion (A) side toward the tip portion (B) side on the outer periphery of the transition portion to From the inner peripheral end on the tip (B) side of the through hole (2) to the small diameter portion (2
At the transitional portion of b) toward the inner peripheral end on the base (A) side, the apex angle (θ
2) is a tapered portion (8) formed on the outer circumference of the needle valve seat (8)
The small diameter part of the through hole (2) from the cooling water chamber (6) side so that the taper part (8c) formed on the outer circumference of the needle valve seat (8) and smaller than the apex angle (θ1) of c) is housed. A tapered through hole (2c) is formed which becomes smaller in diameter toward (2b) and continues to the small diameter portion (2b) of the through hole (2), and the maximum outer diameter of the tapered portion (8c) of the needle valve seat (8). A fuel injection valve, wherein an outer peripheral edge portion of the portion is brought into contact with an inner peripheral edge portion of a maximum inner diameter portion of the tapered through hole (2c). 2. A taper portion (8c) on the outer circumference of the needle valve seat (8) with a contact portion between the taper portion (8c) formed on the outer circumference of the needle valve seat (8) and the tapered through hole (2c) as a base point. Angle (α) of the gap (G) formed between the hole and the tapered through hole (2c)
Is 0 ° ≦ α <90 °, and the tapered through hole (2c)
2. The fuel injection valve according to claim 1, wherein an angle (γ) outside the axis is 90 ° <γ <180 ° with reference to a line orthogonal to the axis of the through hole (2).