JP2003293906A - Fuel injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection device having a filter member in a fuel inlet wherein an uniform chamfer is formed in an inlet of a fuel hole, even when a fuel hole for passing a filter member is opened obliquely. <P>SOLUTION: The fuel injection device comprises a fuel injection pipe 90 having a bag nut 92 and a tip 91a that is locked in the bag nut 92 and connected to a connected object 11 by screwing of the bag nut 92, a fuel inlet connecting part 10 having the connected object 11 in an opening 10a on the fuel inlet side and a fuel inflow hole 12 disposed on the fuel downstream side of the opening 10a, and a filter member 20 inserted and fixed to the fuel inflow hole 12. The fuel inflow hole 12 is disposed to obliquely cross the connected object 11, and a ridge formed of the connected object 11 and the fuel inflow hole 12 is removed in a predetermined spherical surface 15 shape. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fuel injection device.

[0002]

2. Description of the Related Art As a fuel injection device, for example, a fuel injection valve is known which is provided in each cylinder of a diesel engine and injects high-pressure fuel into a combustion chamber of the cylinder. This type of fuel injection valve generally promotes mixing with intake air pressurized in the combustion chamber to improve combustion efficiency of fuel, and therefore, generally,
The injection hole diameter of the fuel injection valve has been reduced. Therefore, it is necessary to prevent foreign matter from being mixed into the fuel flowing into the fuel injection valve.

As a countermeasure against this, a so-called filter member is attached to the fuel passage of the fuel inlet of the fuel injection valve,
There is a filter member having a fuel groove structure engraved in a spiral shape or the like on the outer peripheral surface (Japanese Patent Laid-Open No. 63-272).
961 publication).

According to the disclosure of Japanese Patent Laid-Open No. 63-272961, a fuel injection pump is provided at a fuel inlet portion of the fuel injection valve so that high-pressure fuel discharged from the fuel injection pump or the like is supplied to the fuel injection valve. It has a structure in which it is screwed and fixed by a fuel injection pipe which is connected to the fuel injection valve. The opening shape of the fuel inlet portion is formed into a conical tapered surface in order to secure a sealing surface with the fuel injection pipe. A fuel passage into which the filter member is inserted is formed on the inner side of the tapered surface, and in order to prevent caulking when the filter member is inserted, the inlet portion of the fuel passage is generally chamfered.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the related art disclosed in Japanese Patent Publication No. 2961, etc., when the hole axis of the fuel passage into which the filter member is inserted is opened obliquely with respect to the conical axis forming the sealing surface, the chamfering amount is It becomes non-uniform along the circumferential direction, and in some cases, there may be a portion where chamfering is not formed due to manufacturing variations and the like, and there is a problem that caulking occurs when the filter member is inserted.

The present invention has been made in consideration of such circumstances, and therefore an object thereof is to have a filter member at a fuel inlet portion, and a fuel hole for inserting the filter member is formed obliquely. Even if it is present, it is to provide a fuel injection device capable of forming a uniform chamfer at the inlet of the fuel hole.

[0007]

According to a first aspect of the present invention, there is provided a cap nut and a fuel injection pipe having a tip portion which is locked in the cap nut and is connected to a connection target by screwing the cap nut. A fuel inlet connection portion having the connection target in the opening portion on the fuel inlet side and having a fuel inflow hole provided on the fuel downstream side of the opening portion, and a filter member inserted and fixed in the fuel inflow hole, The fuel inflow hole is arranged so as to obliquely intersect the connection target, and the ridgeline formed by the connection target and the fuel inflow hole is removed in a predetermined spherical shape.

As a result, the axial force generated by the screwing operation of the cap nut is applied to the tip end portion of the fuel injection pipe and the connection target of the fuel inlet connection portion, so that the fuel injection pipe and the fuel inlet connection portion are sealed at high pressure. In addition, a filter member such as a filter member is provided in the fuel inflow hole in order to prevent foreign matter mixed in the fuel and the like from flowing into the fuel downstream side of the fuel inlet connection part and causing functional inhibition. When the fuel inflow holes intersect at an angle, for example, the shape of the connection target is formed by a flat surface or a curved surface such as a cone, and the insertion length of the fuel inflow holes into which the filter member is inserted is caused by the oblique intersection. Compared to the prior art in which the state becomes non-uniform along the direction, the fuel inlet side ridge line shape of the fuel inflow hole newly formed by removing it into a predetermined spherical shape, that is, the insertion length of the fuel inflow hole is Lap It is possible to alleviate the uneven state along the direction. It should be noted that the predetermined spherical surface has a predetermined spherical surface regardless of how the rotation axis of the spherical surface is inclined, and therefore, for example, a spherical surface having a diameter larger than the hole diameter of the fuel inflow hole has a ridge line on the fuel inlet side of the fuel inflow hole. By forming it, it is possible to alleviate the state of uneven ridge lines along the circumferential direction.

Therefore, when chamfering is applied to the ridgeline on the fuel inlet side of the spherically shaped fuel inflow hole, uniform chamfering is possible.

As a method of removing a predetermined spherical surface, even if it is formed by additional machining such as cutting, it is formed as a prepared hole by casting such as forging before cutting the fuel inflow hole and the like. It may be

As described in claim 2 of the present invention, the connection object is formed in a conical surface toward the fuel downstream side in the opening.

As a result, as compared with the case where the ridge line is formed by a cone whose cone axis is inclined with respect to the fuel inflow hole, the ridge line is formed in a spherical shape in which the predetermined spherical surface becomes a predetermined spherical surface no matter how the rotation axis is inclined. Therefore, it is possible to reliably alleviate the state of the uneven ridgeline formed by the connection target, and thus it is possible to form the uniform ridgeline state. Therefore, since the ridgeline on the fuel inlet side of the fuel inflow hole removed by the curved surface can be formed in a uniform ridgeline state, the chamfer formed by additional machining on the uniform ridgeline can also be formed uniformly. is there.

According to the third aspect of the present invention, the fuel inflow hole is arranged on the outer side in the radial direction of the drive member for controlling the back pressure applied to the valve member for opening and closing the injection hole for injecting the fuel. It is suitable for a fuel injection device having a structure that communicates with a high-pressure fuel passage for supplying.

For example, when it is desired to cross the fuel inflow hole obliquely with respect to the connection target due to the structure of the fuel injection device, it is possible to improve the degree of freedom in designing the layout of the members inside the fuel injection device. .

As described in claim 4 of the present invention, the driving member is composed of an elastic body having an elastic force or a switching valve for generating hydraulic pressure.

Thus, as a component of the fuel injection device that causes the fuel inflow hole to cross the connection target obliquely, the fuel injection valve, in particular, the nozzle needle as the valve member and the nozzle needle are slidably held. Even if it is a switching valve such as a three-way valve for controlling the pressure of the back pressure chamber of the nozzle needle, an elastic body such as a built-in compression coil spring in the main body that drives the valve portion including the nozzle body as the valve body The present invention can be applied.

According to the fifth aspect of the present invention, the radial center of the spherical surface is on the axis of the fuel inflow hole.

As a result, the ridgeline on the fuel inlet side of the fuel inflow hole removed by the curved surface becomes a circle if the shape of the fuel inflow hole is circular so that the insertion length of the filter member is along the circumferential direction. A uniform ridge can be formed. Therefore, the chamfer formed by additional machining on this ridge line can be formed in a uniform state along the circumferential direction.

The chamfering process can be facilitated as compared with the conventional technique in which the spherical surface is not removed.

According to the sixth aspect of the present invention, the radius center of the spherical surface is arranged on the axis of the fuel inflow hole and the axis to be connected.

Thus, in order to make the chamfered state formed by additional machining on the ridgeline uniform along the circumferential direction and to secure a high-pressure seal between the fuel inlet connection portion of the fuel injection device and the fuel injection pipe. Even in the connection target, that is, the seal surface, the width of the seal surface can be made uniform along the circumferential direction. For example, it is possible to increase the inclination angle of the fuel inflow hole with respect to the connection target by, for example, ensuring the width of the range to be the sealing surface with the tip end of the connection target and expanding the predetermined radius of the predetermined spherical surface. It is possible.

According to claim 7 of the present invention, it is suitable for a fuel injection device having a structure in which a chamfer is formed on the fuel inlet side of the fuel inflow hole.

According to claim 8 of the present invention, as the fuel injection device of the present invention, a fuel injection device which is provided in each cylinder of an internal combustion engine and supplies high-pressure fuel to the combustion chamber of the cylinder, that is, a fuel injection valve is suitable. Is. For example, it is possible to facilitate the design of the layout of the built-in members of the fuel injection valve that need to be formed in a substantially cylindrical shape due to the layout restrictions of the intake valve and the exhaust valve that are introduced into and discharged from the combustion chamber.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The fuel injection device of the present invention is applied to a fuel injection valve which is provided in each cylinder of an internal combustion engine and which supplies high-pressure fuel to the combustion chamber of the cylinder to embody it. It will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a partial cross-sectional view showing a schematic configuration of a fuel injection device of this embodiment. FIG. 2 is a cross-sectional view showing the structure around the fuel inlet connection part, which is the main part of the present invention in FIG.

As shown in FIG. 1, a fuel injection valve 1 as a fuel injection device is provided in each cylinder of an internal combustion engine such as a diesel engine and injects high pressure fuel into the combustion chamber of the cylinder. , A fuel inlet connection portion 10 to which fuel pumped from a fuel injection pump or the like is supplied, and a so-called filter member 20 inserted into and fixed to a fuel inflow hole formed inside the fuel inlet connection portion 10. Has been done.
The fuel inlet connection part 10 connects the fuel inlet connection part and the fuel injection pump to a fuel injection pipe 90 having therein a fuel passage 90a through which high-pressure fuel discharged from the fuel pump flows. It is possible.

The fuel inlet connection portion 10 is formed, for example, as a fuel injection valve having an injection hole 3a for atomizing high-pressure fuel into an internal combustion engine and injecting it in a spray form. It is a part of a high-pressure fuel passage portion that supplies high-pressure fuel to the built-in injection hole 3a. Further, the fuel inlet connection portion 10 introduces high-pressure fuel supplied from a fuel pump or the like into the fuel injection valve 1, and therefore, the front end side of the fuel injection pipe 90, specifically, the high-pressure pipe 9 that forms the fuel passage 90.
1 is provided in the opening 10a on the fuel inlet side so that a connection target capable of high-pressure sealing with the front end portion 91a of No. 1 is provided, and the communication relationship between the fuel injection pipe and the fuel inlet connecting portion is hermetically sealed under high pressure and connected. It is not limited to the fuel injection valve as long as it is necessary, and it may be provided in any fuel injection device.

The fuel inlet connection portion 10, that is, the fuel injection device 1 described in the present embodiment will be described as a fuel injection valve which is provided in each cylinder of an internal combustion engine and injects high-pressure fuel into the combustion chamber of the cylinder. .

The opening 10a of the fuel inlet connection 10
Details of the internal shape and the like will be described later.

The fuel injection pipe 90 has a fuel passage 90a through which high-pressure fuel passes, and both ends of the fuel passage 90a are in contact with a connection target 11 and a tip portion 9 capable of high-pressure sealing.
A high-pressure pipe 91 having 1a, and a cap nut 92 for tightening by screwing capable of setting the surface pressure due to the surface contact between the tip 91a abutting against the connection target 11 and the connection target 11 to a surface pressure capable of high-pressure sealing. It is a well-known high-pressure fuel injection pipe equipped with. The tip portion 91a has a conical portion 91a1 having a conical surface that can be fitted into a connection target, and a flange formed adjacent to the conical portion 91a1 and having a large diameter that can be locked in the cap nut 92. And a portion 91a2. In addition,
As shown in FIG. 1, the conical portion 91a1 of the tip portion 91a is fitted to the connection target 11, and the female screw portion 92b provided on the inner periphery of the opening end side of the cap nut 92 is provided on the outer periphery of the fuel inlet connection portion 10. The male screw portion 10b is screwed and tightened, and the shoulder portion 92 in the tightening axial force cap nut 92 generated by this tightening is generated.
By bringing a into contact with the flange portion 91a2, a tightening axial force generated by the tightening is applied to the contact surface of the tip end portion 91a of the fuel injection pipe 90 and the connection target 11 of the fuel inlet connection portion 10, A surface pressure capable of high-pressure sealing is generated. As a result, the fuel injection pipe 90 and the fuel inlet connection part 10 are communicated with each other in a state where the connection state is high-pressure airtight.

Here, the connection target 11 is the fuel injection pipe 90.
(Specifically, the fuel injection pipe 90 is screwed by the cap nut 92) (specifically, the tip portion 91a of the high pressure pipe 91).
As long as it is a curved surface that can be airtightly contacted with, it is not limited to the conical surface corresponding to the conical surface of the tip portion 91a (specifically, the conical portion 91a1) described above, and is deformed by the tightening axial force by screwing. Therefore, a curved surface shape that is approximate to a conical surface that is a curved surface that can airtightly contact the tip portion 91a may be used.

The connection target 11 described in the present embodiment
As the shape of, the shape corresponding to the shape of the tip 91a,
That is, the following description will be made assuming that it is formed on a conical surface corresponding to the conical surface of the conical portion 91a1.

Fuel injection valve 1 with fuel inlet connection 10
Is provided in each cylinder of the internal combustion engine, and supplies high-pressure fuel to the combustion chamber of the cylinder, and from the viewpoint of layout restrictions with the intake valve and the exhaust valve that are introduced into and discharged from the combustion chamber, It is formed in a substantially cylindrical shape. In the fuel injection valve 1, as shown in FIG. 1, fuel pressure-fed from a fuel injection pump (not shown) is supplied from the fuel inlet connection portion 10 into the fuel injection valve 1 via the fuel injection pipe 90, The injection is performed from an injection hole 3a provided at the tip of the injection valve 1. The fuel injection valve 1 has a nozzle needle (not shown) as a valve member that opens and closes the injection hole 3a.
And a main body 1 (hereinafter referred to as a holder) having a valve portion 3 having a nozzle body 3b, a compression coil spring 29 as a driving member for adjusting the back pressure applied to the nozzle needle, and a fuel inlet connection portion 10. It is composed of.
The main body 2 and the valve 3 are provided with a retaining nut 4
It is tightened by and is assembled integrally.

Details of the fuel inlet connection portion 10, which is a feature of the present invention, will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, in the fuel inlet connection portion 10, a conical surface 11 to be connected is formed in an opening 10a on the fuel inlet side, and the opening 10a, that is, the conical surface 1 is formed.
1, a fuel inflow hole 12 is formed on the fuel downstream side. Further, on the downstream side or in the vicinity of the fuel inlet side of the fuel inflow hole 12, an edge as a filter member is provided in the fuel inflow hole 12 in order to prevent foreign matter from entering the fuel injection valve 1, particularly the injection hole 3a. The filter 20 is arranged so as to be inserted and fixed. The edge filter 20 is a well-known one having a fuel groove formed in a vertical groove shape (see FIG. 1) or a spiral shape on the outer circumference.

Here, the fuel inflow hole 12 is arranged on the axis of the fuel injection valve 1, as shown in FIG. 1, and the valve portion 3, that is, the valve, which is also arranged on the axis of the fuel injection valve 1. Due to the restriction of the arrangement position with the driving member (compression coil spring) 29 that applies back pressure to the nozzle needle that opens and closes the injection hole 3a of the portion 3, the high pressure fuel passage 13 that is arranged on the radially outer side of the compression coil spring 29 and the high-pressure fuel passage 13 obliquely. So as to intersect with each other, and as a result, the axis 1 of the cone which is the central axis of the conical surface 11 to be connected.
1j is arranged so that the axis 12j of the fuel inflow hole obliquely intersects (in FIG. 1, the central axis 11j to be connected and the axis 12j of the fuel inflow hole obliquely intersect at an angle φ on the paper surface). is doing).

Generally, the conical surface 11 (specifically, the shaft 11
When the fuel inflow hole 12 (specifically, the shaft 12j) intersects diagonally with j), it occurs when the conical surface 11 and the fuel inflow hole 12 simply intersect with each other as a comparative example indicated by a two-dot chain line in FIG. At the ridge line, as the insertion length H (specifically, Hp in the comparative example) of the fuel inflow hole 12 into which the filter member 20 is inserted, the variation in the insertion length along the circumferential direction is as shown in FIG. When the insertion length Hp2 on the left side of the paper surface is set, the insertion length Hp1 on the right side of the paper surface may be considerably shortened (H
p2> Hp1). That is, the insertion length Hp along the circumferential direction
A non-uniform state of occurs. Therefore, the filter member 2
If chamfering is attempted on this ridge line portion to prevent crimping when inserting 0, chamfering (tapered chamfer shown in FIG. 2) also causes a non-uniform state along the circumferential direction. May cause a portion where chamfer is not formed. That is, although the chamfer is formed, the chamfer is not formed in a part of the circumferential direction, which causes a problem that a caulking occurs when the filter member is inserted.

Therefore, in this embodiment, FIG. 1 and FIG.
2, the ridgeline formed by the conical surface 11 and the fuel inflow hole 12 is removed into a predetermined spherical surface (for example, a spherical surface having a diameter larger than the diameter of the fuel inflow hole shown in FIG. 2) 15. To do. In other words, when the conical axis 11j of the conical surface 11 is inclined with respect to the fuel inflow hole 12, the shape and position of the ridge line on the conical surface 11 that intersects changes in accordance with the inclined angle φ, whereas No matter how the rotation axis of the predetermined spherical surface 15 is tilted, the shape of the predetermined spherical surface 15 remains as long as the center point of the spherical surface 15 remains unchanged. There is no change in the shape and position of the ridge line.

As a result, a predetermined spherical surface (a spherical surface having a diameter larger than the diameter of the fuel inflow hole) 15 is removed, so that a non-uniform state is formed on the fuel inlet side of the fuel inflow hole 12 along the circumferential direction. Relaxed ridges (see dashed lines in Figure 2) can be formed.

Therefore, when chamfering (tapered chamfer shown in FIG. 2) is applied to the ridgeline on the fuel inlet side of the spherically shaped fuel inflow hole 12, uniform chamfering is possible (FIG. 2). The tapered chamfer has a diameter D and a taper angle θ as shown in FIG.

Further, in this embodiment, the predetermined spherical surface 15
Since the center point (specifically, the center point O of the radius SR) is arranged on the axis 12j of the fuel inflow hole 12, the ridgeline on the fuel inlet side of the fuel inflow hole 12 formed in the spherical surface 15 is formed in the circumferential direction. The chamfer can be formed uniformly along the circumferential direction when chamfering the ridgeline (the insertion length Hi of the present embodiment shown in FIG. 2).
In, the insertion length Hi2 on the left side of the paper is the same as the insertion length Hi1 on the right side of the paper.

When chamfering is to be performed in the circumferential direction in a predetermined non-uniform state as compared with the prior art in which the spherical surface 15 is not removed, the embodiment of the present invention is applied. The chamfering process can be facilitated.

(Second Embodiment) As a second embodiment, FIG. 3 shows the center point of the predetermined spherical surface 15 described in the first embodiment (specifically, the center point O of the radius SR). On the shaft 12j of the fuel inflow hole 12 and the fuel injection valve 1
Is arranged on the axis (specifically, the conical axis 12j in FIG. 3) 1j. FIG. 3 is a cross-sectional view showing the structure around the fuel inlet connection portion according to the present embodiment.

As a result, the chamfered state formed by additional machining on the ridge line formed in a predetermined spherical shape is made uniform along the circumferential direction, and the fuel inlet connection portion 10 of the fuel injection valve 1 is formed. Even in the connection target (conical surface) 11 for ensuring a high-pressure seal with the fuel injection pipe 90, that is, the sealing surface,
The width of the sealing surface can be made uniform along the circumferential direction (see FIG. 3).

For example, the tip 91a of the conical surface 11
Securing the width of the range that becomes the sealing surface with
By increasing the predetermined radius SR of 5 or the like, it is possible to increase the inclination angle φ of the fuel inflow hole 12 (specifically, the shaft 12j) with respect to the conical surface 11 (specifically, the conical shaft 11j).

(Modification) As a first modification, a chamfered shape formed by additional machining on the ridgeline formed in the predetermined spherical surface 15 described in the first embodiment is changed to a tapered chamfer. Instead, as shown in FIG. 4, the chamfering may be performed. FIG. 4 is a cross-sectional view showing the structure around the fuel inlet connection portion according to this modification.

By removing with a predetermined spherical surface (spherical surface having a diameter larger than the diameter of the fuel inflow hole) 15, the fuel inflow hole 12 is removed.
Since a ridgeline (see the broken line shown in FIG. 2) in which the non-uniform state is relaxed can be formed along the circumferential direction on the fuel inlet side, along the ridgeline, the chamfering does not disappear and the ridgeline extends along the circumferential direction. R chamfering that is formed in a uniform state is possible.

As a second modification, at the center point O of the predetermined spherical surface 15 described in the first embodiment, as shown in FIG. 5, not necessarily on the axis 12j of the fuel inflow hole 12 and on the fuel injection valve. Even if the center point O of the radius SR is not arranged on the axis 1j of 1, the radius SR of the predetermined spherical surface 15 may be increased. FIG. 5 is a cross-sectional view showing the structure around the fuel inlet connection portion according to this modification.

As described in the first embodiment, the predetermined spherical surface 15 has the spherical surface 1 no matter how the rotation axis is tilted.
As long as the center point O of 5 does not change, the shape of the predetermined spherical surface 15 remains, so that the center point O of the shaft 12 of the fuel inlet hole 12
j or on the axis 1j of the fuel injection valve 1 within a predetermined range, the chamfered state formed by additional machining on the ridge line formed by the predetermined spherical surface 15 is changed to the circumferential direction. It is possible to achieve uniformity along the line.

Therefore, the predetermined radius S of the predetermined spherical surface 15
By enlarging R, the conical surface 11 (specifically, the conical axis 1
1j) fuel inlet hole 12 (specifically, shaft 12j)
It is possible to increase the inclination angle φ of. The degree of freedom in designing the inclination angle φ of the fuel inflow hole 12 (specifically, the shaft 12j) due to the structural layout of the fuel injection valve 1 can be improved.

The compression coil spring 29 for adjusting the valve opening pressure of the nozzle needle has been described as a driving member for applying a back pressure to the nozzle needle for opening and closing the injection hole 3a of the valve portion 3 described in the present embodiment. The drive member for driving the valve portion 3 incorporated in the main body portion 2 of the fuel injection valve 1 is not limited to an elastic body such as a compression coil spring, but a switching valve such as a three-way valve for controlling the pressure of the back pressure chamber at the nozzle needle. Even if there is, the effect described in the embodiment of the present invention can be obtained.

According to the present embodiment described above,
Due to the structure of the fuel injection valve, that is, the fuel injection device, it is configured inside the fuel injection device when it is desired to intersect the fuel inlet hole 12 obliquely with the connection target (conical surface 11) of the fuel inlet connection portion 10. The degree of freedom in designing the layout of members can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a schematic configuration of a fuel injection device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure around a fuel inlet connection part which is a main part of the present invention in FIG.

FIG. 3 is a cross-sectional view showing a configuration around a fuel inlet connection portion according to a second embodiment.

FIG. 4 is a cross-sectional view showing a structure around a fuel inlet connection portion according to a first modification.

FIG. 5 is a cross-sectional view showing a configuration around a fuel inlet connection portion according to a second modification.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Fuel injection valve (fuel injection device) 1j Fuel injection valve shaft 2 Main body 3 Valve part 3a Injection hole 10 Fuel inlet connection 10a Opening 11 Connection target (conical surface) 11j Conical surface axis (conical axis) 12 Fuel Inflow hole 12j Fuel inflow hole shaft 13 High-pressure fuel passage 15 Spherical surface 20 Edge filter (filter member) 29 Driving member (compression coil spring) 90 Fuel injection pipe 90a Fuel passage 91 High-pressure pipe 91a Tip portion 91a1 Conical portion 92 Cap nut SR Spherical surface Radius O Center point (sphere) φ of spherical surface Angle H (Fuel member 20 is inserted) Fuel inlet hole 12
Insertion length Hp (Hp1, Hp2) of Comparative Example Insertion length Hi (Hi1, Hi2) Insertion length of this embodiment θ Chamfered taper angle D Chamfered outer diameter RR Chamfered

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Claims (8)

[Claims] 1. A fuel injection pipe having a cap nut and a tip end portion which is locked in the cap nut and is connected to a connection target by screwing the cap nut, and the connection target is provided in an opening on a fuel inlet side. And a fuel inlet connection portion having a fuel inflow hole provided on the fuel downstream side of the opening, and a filter member inserted and fixed in the fuel inflow hole, wherein the fuel inflow hole is connected to the connection target. And a ridgeline formed by the connection target and the fuel inflow hole is removed in a predetermined spherical shape. 2. The fuel injection device according to claim 1, wherein the connection target is formed as a conical surface toward the fuel downstream side in the opening. 3. The high-pressure fuel passage, wherein the fuel inflow hole is arranged radially outside a drive member that controls a back pressure applied to a valve member that opens and closes a fuel injection nozzle hole, and supplies fuel to the injection hole. The fuel injection device according to claim 1 or 2, which is in communication with the fuel injection device. 4. The fuel injection device according to claim 3, wherein the drive member includes an elastic body having an elastic force, or a switching valve that generates hydraulic pressure. 5. The fuel injection device according to claim 1, wherein the radial center of the spherical surface is on the axis of the fuel inflow hole. 6. The radial center of the spherical surface is arranged on the axis of the fuel inflow hole and the axis of the connection target, according to any one of claims 1 to 4. The fuel injection device described. 7. The fuel injection device according to claim 1, wherein a chamfer is formed on a fuel inlet side of the fuel inflow hole. 8. The fuel injection device according to any one of claims 1 to 7 is provided in each cylinder of an internal combustion engine,
A fuel injection device for injecting and supplying high-pressure fuel to a combustion chamber of the cylinder.