WO2023139815A1

WO2023139815A1 - Fuel injection device

Info

Publication number: WO2023139815A1
Application number: PCT/JP2022/027702
Authority: WO
Inventors: 泰介杉井; 明靖宮本; 威生三宅; 真士菅谷; 貴敏飯塚; 寛向井; 直樹米谷
Original assignee: 日立Astemo株式会社
Priority date: 2022-01-18
Filing date: 2022-07-14
Publication date: 2023-07-27
Also published as: JP2023104448A

Abstract

This fuel injection device comprises a nozzle holder, a fixed core, an anchor, and a valve member. The valve member has a valve body and a spacer. The valve body is provided with a shaft portion and an engaging portion that engages with the anchor during a valve-opening action. The spacer has a housing portion in which the engaging portion is housed, and forms a predetermined gap between the engaging portion and the anchor when the valve closes. A fluid resistance reduction portion that reduces the resistance of fluid is provided between the engaging portion and the anchor.

Description

fuel injector

The present invention relates to a fuel injection device.

Conventionally, as an internal combustion engine, an in-cylinder injection type internal combustion engine in which a fuel injection device directly injects fuel into the cylinder has been used. BACKGROUND ART For example, Japanese Patent Laid-Open No. 2002-100000 discloses a technology related to a conventional fuel injection device.

Patent Literature 1 describes a technology related to a fuel injection device that includes a valve body and an injection hole forming portion in which a plurality of injection holes for injecting fuel are formed on the tip side of the valve body. Patent document 1 describes that the valve body consists of a second valve body that contacts the anchor when the valve is closed, and a first valve body that contacts the anchor while the valve is open. In the technique described in Patent Document 1, the lengths of the second valve body and the second valve body are defined so that when the valve is opened, the second valve body abuts against a stroke stopper arranged on the inner circumference of the fixed core, and when the valve is opened, the fixed core and the anchor do not directly abut to ensure a gap.

JP 2014-227958 A

However, the technique described in Patent Document 1 has a problem that the fluid force generated between the first valve body and the second valve body and between the first valve body and the anchor during the valve opening operation hinders the responsiveness during the valve opening operation, resulting in variations in the valve opening operation. In addition, variation in the valve opening operation causes variation in the amount of fuel injection.

It is an object of the present invention to provide a fuel injection device capable of suppressing variations in fuel injection amount in consideration of the above problems.

In order to solve the above problems and achieve the object, a fuel injection device includes a nozzle holder, a stationary core, an anchor, and a valve member. The nozzle holder is provided with an injection hole forming member. A fixed core is arranged in the nozzle holder. An anchor is positioned opposite the fixed core. A valve member is movably disposed in the nozzle holder.
The valve member has a valve body and a spacer. The valve body is provided with a shaft portion for opening and closing the injection hole provided in the injection hole forming member and an engaging portion that engages with the anchor during the valve opening operation. The spacer has an accommodating portion in which the engaging portion is accommodated, and forms a predetermined gap between the engaging portion and the anchor when the valve is closed. A fluid resistance reducing portion that reduces fluid resistance is provided between the engaging portion and the anchor.

According to the fuel injection device configured as described above, it is possible to suppress variations in the amount of fuel injected.

1 is a sectional view showing a fuel injection device according to a first embodiment; FIG. FIG. 2 is an enlarged cross-sectional view showing the periphery of a spacer in the fuel injection device according to the first embodiment; FIG. 4 is an enlarged cross-sectional view showing the periphery of a spacer when valve opening starts in the fuel injection device according to the first embodiment; FIG. 4 is an enlarged cross-sectional view showing the periphery of the spacer when the valve opening operation in the fuel injection device according to the first embodiment is completed; and FIG. 9 is a cross-sectional view showing an enlarged view of the surroundings of a spacer in a conventional fuel injection device. FIG. 10 is an enlarged cross-sectional view showing the periphery of a spacer when valve opening starts in a conventional fuel injection device; FIG. 10 is an enlarged cross-sectional view showing the surroundings of a spacer when the valve opening operation in the conventional fuel injection device is completed; FIG. 7 is an enlarged cross-sectional view showing the periphery of a spacer in a fuel injection device according to a second embodiment; FIG. 11 is an enlarged cross-sectional view showing the periphery of a spacer in a fuel injection device according to a third embodiment; FIG. 11 is an enlarged cross-sectional view showing a periphery of a spacer in a fuel injection device according to a fourth embodiment; FIG. 11 is an enlarged cross-sectional view showing the periphery of a spacer in a fuel injection device according to a fifth embodiment; FIG. 11 is an enlarged cross-sectional view showing the periphery of a spacer in a fuel injection device according to a sixth embodiment;

Embodiments of the fuel injection device will be described below with reference to FIGS. 1 to 12. FIG. In addition, the same code|symbol is attached|subjected to the member which is common in each figure.

1. First embodiment example 1-1. Configuration of Fuel Injection Apparatus First, the configuration of a fuel injection apparatus according to a first embodiment (hereinafter referred to as "this example") will be described with reference to FIG.
FIG. 1 is a cross-sectional view showing a fuel injection device.

The fuel injection device shown in FIG. 1 is used as an internal combustion engine in a four-cycle engine that repeats four strokes of an intake stroke, a compression stroke, a combustion (expansion) stroke, and an exhaust stroke. Further, the fuel injection device is applied to an in-cylinder injection type internal combustion engine that injects fuel into each cylinder.

As shown in FIG. 1, the fuel injection device 1 includes a fixed core (magnetic core) 101, a nozzle holder 102, an injection hole forming member 103, a valve member 104, an electromagnetic coil 108, a housing 109, an anchor (movable core) 110, and a connecting portion 135. The fuel injection device 1 also includes a first spring 118 , a second spring 124 and a third spring 126 .

[Nozzle holder]
The nozzle holder 102 is formed in a cylindrical shape. An injection hole forming member 103 is inserted or press-fitted to the tip of the nozzle holder 102 along the central axis AX1 in the axial direction Da (hereinafter simply referred to as "axial direction Da"). An injection hole 112 for injecting fuel is formed in the injection hole forming member 103 .

Further, the injection hole forming member 103 is formed with a valve seat 103a to which the tip of the valve body 113 of the valve member 104 described later is separated and contacted. The injection hole forming member 103 seals the fuel when the valve body 113 is seated on the valve seat 103a. Further, the valve body 113 seals the fuel by coming into contact with the valve seat 103a, and permits passage of the fuel by separating from the valve seat 103a.

A guide member 105 is fixed to the tip of the nozzle holder 102 by press fitting or plastic coupling. The guide member 105 supports the outer peripheral surface of the valve body 113 in the valve member 104 and guides movement of the valve body 113 .

A large-diameter portion 102a having an outer diameter larger than that of the tip portion is formed at the rear end portion, which is the other end portion of the nozzle holder 102 in the axial direction Da. An internal space 102b is formed in the large diameter portion 102a. This internal space 102b communicates with the tip through a communication hole 102c formed along the axial direction Da of the nozzle holder 102 .

The internal space 102b is a recess with a bottom that opens at the rear end side of the large diameter portion 102a and is recessed toward the tip side in the axial direction Da. An anchor 110, which will be described later, and part of the fixed core 101 are arranged in the internal space 102b. One end of the second spring 124 is accommodated in the central portion of the bottom of the internal space 102b.

[Valve member]
A valve member 104 is arranged inside the nozzle holder 102 so as to be movable along the axial direction Da. The valve member 104 has a valve body 113 , a spacer 125 , a third spring 126 and a rod head 127 . The valve body 113 is composed of a cylindrical rod-shaped member. The valve body 113 is inserted through an insertion hole 110c (see FIG. 2) of the anchor 110, which will be described later, and arranged in the communication hole 102c of the nozzle holder 102. As shown in FIG. The distal end portion of the valve body 113 in the axial direction Da abuts on the valve seat 103a of the injection hole forming member 103 so as to be separated from the valve seat 103a, thereby opening and closing the injection hole 112 provided in the injection hole forming member 103.

A connection recess 113b (see FIG. 2) is formed at the rear end of the valve body 113 in the axial direction Da. A connection protrusion 127a (see FIG. 2) of the rod head 127 is fitted into the connection recess 113b. Thereby, the rod head 127 is connected to the rear end portion of the valve body 113 .

The rod head 127 is formed in a substantially disc shape and slides in a through hole 101a of the fixed core 101, which will be described later. The tip of the first spring 118 in the axial direction Da contacts the rod head 127 . A third spring 126 and a spacer 125 are arranged between the rod head 127 and the valve body 113 .

The spacer 125 is in contact with the upper end surface 110a (see FIG. 2) of the anchor 110, which will be described later. The third spring 126 abuts on the spacer 125 at its tip in the axial direction Da, and abuts on the rod head 127 at its rear end in the axial direction Da. That is, the third spring 126 is interposed between the rod head 127 and the spacer 125 to bias the spacer 125 toward the anchor 110 .

The detailed configurations of the valve body 113, the spacer 125 and the third spring 126 will be described later.

[anchor]
Next, the anchor 110 will be explained. The anchor 110 is arranged in the inner space 102b of the nozzle holder 102 between the spacer 125 of the valve member 104 and the bottom of the inner space 102b. A minute gap is formed between the outer peripheral surface of the anchor 110 and the inner peripheral surface of the internal space 102b. Therefore, the anchor 110 is arranged movably along the axial direction Da within the internal space 102b.

The anchor 110 is formed in a cylindrical shape. The anchor 110 is formed with an insertion hole 110c (see FIG. 2) and an eccentric through hole 110d. The insertion hole 110c and the eccentric through hole 110d are guide holes that penetrate from the front end portion to the rear end portion of the anchor 110 in the axial direction Da. The insertion hole 110c is formed on the central axis of the anchor 110. As shown in FIG. A valve body 113 of the valve member 104 is inserted through the insertion hole 110c.

The eccentric through hole 110d is formed at a position eccentric from the central axis of the anchor 110. The eccentric through hole 110 d communicates with the flow path formed by the through hole 101 a of the fixed core 101 . The eccentric through-hole 110d forms a flow path through which fuel passes.

The rear end portion of the second spring 124 is in contact with the end face of the anchor 110 on the tip side in the axial direction Da. Therefore, the second spring 124 is interposed between the anchor 110 and the inner space 102b of the nozzle holder 102. As shown in FIG. A fixed core 101 is arranged on the rear end side of the anchor 110 in the axial direction Da.

A tapered portion 110b is formed at a corner portion of the insertion hole 110c of the anchor 110 on the side of the upper end surface 110a. The diameter of the tapered portion 110b increases toward the rear end side in the axial direction Da. An engaging portion 128 of the valve body 113, which will be described later, abuts against the tapered portion 110b.

[Fixed core]
The fixed core 101 will be explained. The fixed core 101 is a member that attracts the anchor 110 by magnetic attraction. The fixed core 101 is formed in a substantially cylindrical shape having unevenness on the outer peripheral surface. The tip of the fixed core 101 in the axial direction Da is press-fitted inside the large-diameter portion 102a of the nozzle holder 102, that is, inside the internal space 102b. Then, the nozzle holder 102 and the fixed core 101 are joined by welding. Thereby, the gap between the nozzle holder 102 and the fixed core 101 is sealed, and the space inside the nozzle holder 102 is sealed.

In addition, the distal end portion 101b of the fixed core 101 faces the end surface (upper end surface 110a) on the other end side in the axial direction Da of the anchor 110 arranged in the internal space 102b. The rear end side of the fixed core 101 in the axial direction Da protrudes from the internal space 102b of the nozzle holder 102 toward the rear end in the axial direction Da.

A through hole 101 a is formed in the fixed core 101 . The through hole 101a is formed coaxially with the center axis AX1. The through hole 101a forms a flow path through which fuel passes. A fuel supply port 111 communicating with the through hole 101a is formed at the rear end portion of the fixed core 101 in the axial direction Da. Fuel is introduced from the fuel supply port 111 toward the through hole 101a.

Further, a first spring 118 and an adjusting member 119 are arranged on the tip end side of the through hole 101a in the axial direction Da. The first spring 118 is arranged closer to the distal end of the through hole 101 a than the adjustment member 119 is. The adjusting member 119 is press-fitted into the through hole 101 a and fixed inside the fixed core 101 . A rod head 127, a third spring 126 and a spacer 125 of the valve member 104 are inserted into the through hole 101a.

The first spring 118 is interposed between the adjustment member 119 and the rod head 127 of the valve member 104 . The first spring 118 urges the valve member 104 toward the tip of the nozzle holder 102 in the axial direction Da.

Further, by adjusting the fixing position of the adjusting member 119 with respect to the fixed core 101, the biasing force of the first spring 118 on the valve member 104 can be adjusted. This makes it possible to adjust the initial load that the tip portion of the valve body 113 of the valve member 104 presses against the valve seat 103a provided on the injection hole forming member 103 of the nozzle holder 102 .

Here, the biasing force of the first spring 118 biasing the valve member 104 toward the tip of the nozzle holder 102 is set larger than the biasing force of the second spring 124 biasing the anchor 110 toward the fixed core 101 .

[coil]
Next, the electromagnetic coil 108 will be explained. The electromagnetic coil 108 is wound around a cylindrical coil bobbin. The electromagnetic coil 108 is wound around a coil bobbin and arranged so as to cover part of the outer peripheral surface of the large diameter portion 102 a of the nozzle holder 102 and part of the outer peripheral surface of the tip of the fixed core 101 . The winding start and winding end portions of the electromagnetic coil 108 are connected to power supply terminals of a connector 136 of a connecting portion 135 to be described later via wiring (not shown). A housing 109 is fixed around the outer circumference of the electromagnetic coil 108 .

[housing]
The housing 109 is formed in a cylindrical shape with a bottom. A guide hole is formed in the bottom portion of the housing 109, which is the tip portion in the axial direction Da. A guide hole is formed in the center of the bottom. A nozzle holder 102 is inserted into this guide hole. The opening edge of the guide hole and the outer peripheral surface of the nozzle holder 102 are welded, for example, over the entire circumference. The nozzle holder 102 is thereby fixed to the housing 109 .

Further, the housing 109 is arranged so as to surround the distal end side of the fixed core 101 , the coil bobbin, and the outer periphery of the electromagnetic coil 108 . The inner peripheral surface of the housing 109 faces the nozzle holder 102 and the electromagnetic coil 108 and forms an outer peripheral yoke portion. Thus, a magnetic circuit including the fixed core 101, the anchor 110, the nozzle holder 102 and the housing 109 is formed around the electromagnetic coil .

[Connection part]
The connecting portion 135 is made of resin. The connecting portion 135 is filled between the fixed core 101 and the housing 109 . Further, the connection portion 135 covers the outer peripheral surface of the fixed core 101 excluding the rear end portion of the fixed core 101 on the rear end side of the housing 109 in the axial direction Da. The connecting portion 135 is then molded to form a connector 136 having terminals for power supply. The terminals are connected to connection terminals of a plug (not shown). The fuel injector 1 is thereby connected to a high voltage power supply or a battery power supply. The energization of the electromagnetic coil 108 is controlled by an engine control unit (ECU) (not shown).

1-2. Detailed Configuration of Valve Member Next, detailed configurations of the valve body 113, the spacer 125, and the third spring 126 that constitute the valve member 104 will be described with reference to FIGS. 2 and 3. FIG.
FIG. 2 is an enlarged cross-sectional view showing the periphery of the spacer 125 in the fuel injection device 1, and FIG. 3 is an enlarged view showing the periphery of the spacer 125 when the valve starts to open. Note that FIG. 2 shows the valve closed state.

As shown in FIG. 2, the valve body 113 has a shaft portion 113a that passes through the insertion hole 110c of the anchor 110, an engaging portion 128 that engages with the anchor 110, and a sliding shaft portion 129 that indicates the shaft portion.

The engaging portion 128 is formed closer to the rear end portion in the axial direction Da than the shaft portion 113a. The diameter of the engaging portion 128 is larger than the diameter of the shaft portion 113a and the inner diameter of the insertion hole 110c. The engaging portion 128 protrudes radially outward from the outer peripheral surface of the shaft portion 113a. The engaging portion 128, the shaft portion 113a and the sliding shaft portion 129 are integrally formed by cutting.

The engaging portion 128 has an upper end surface 128a, a lower end surface 128b, a first curved surface portion 128c, a second curved surface portion 128d, a cylindrical portion 128e, a first contact portion 128f, and a second contact portion 128g. The upper end face 128a is formed on the rear end side of the engaging portion 128 in the axial direction Da, and the lower end face 128b is formed on the leading end side of the engaging portion 128 in the axial direction Da. The lower end surface 128 b faces the upper end surface 110 a of the anchor 110 . The cylindrical portion 128e is formed on the side surface of the engaging portion 128 along the axial direction Da.

The first curved surface portion 128c is formed at the corner where the cylindrical portion 128e and the lower end surface 128b are connected, and the second curved surface portion 128d is formed at the corner where the cylindrical portion 128e and the upper end surface 128a are connected. The cylindrical portion 128e is formed between the first curved portion 128c and the second curved portion 128d. The first curved surface portion 128c is formed with a first contact portion 128f that contacts the tapered portion 110b of the anchor 110 described later, and the second curved surface portion 128d is formed with a second contact portion 128g that contacts the tapered portion 16b of the accommodation portion 16 described later.

In the closed state, a gap G2 is provided between the first contact portion 128f of the first curved surface portion 128c and the contact portion 110e of the tapered portion 110b. When the valve is opened, that is, when the positions of the anchor 110 and the valve body 113 are displaced, the contact portion 110e of the anchor 110 contacts the first contact portion 128f of the engagement portion 128, and the anchor 110 and the engagement portion 128 are engaged (see FIGS. 4 and 5). As a result, the valve body 113 moves together with the anchor 110 toward the rear end side in the axial direction Da, that is, in the valve opening direction. Here, a region formed by the shaft portion 113a, the engaging portion 128, and the tapered portion 110b of the anchor 110, and which is generally on the inner diameter side of the first contact portion 128f and the contact portion 110e, is referred to as region B.

The sliding shaft portion 129 is formed closer to the rear end portion in the axial direction Da than the engaging portion 128 is. The sliding shaft portion 129 protrudes from the engaging portion 128 toward the rear end in the axial direction Da. Also, the diameter of the sliding shaft portion 129 is formed to be smaller than the diameter of the engaging portion 128 . A connecting concave portion 113b is formed on the rear end surface of the sliding shaft portion 129 in the axial direction Da. As described above, the connection protrusion 127a of the rod head 127 is fitted into the connection recess 113b.

A spacer 125 is arranged so as to surround the engaging portion 128 and the sliding shaft portion 129 of the valve body 113 . As shown in FIGS. 2 and 3, the spacer 125 has a substantially cylindrical shape. The spacer 125 has a large diameter portion 11 and a small diameter portion 12 that serves as a guide portion. The large-diameter portion 11 and the small-diameter portion 12 are formed concentrically, and the large-diameter portion 11 is formed closer to the tip side in the axial direction Da than the small-diameter portion 12 is. The diameter of the large diameter portion 11 is formed larger than the diameter of the small diameter portion 12 .

In addition, a stepped surface 13 is formed at a portion where the large diameter portion 11 and the small diameter portion 12 of the spacer 125 are connected. The stepped surface 13 protrudes substantially perpendicularly outward in the radial direction from the outer peripheral surface of the small diameter portion 12 . The tip side of the third spring 126 in the axial direction Da contacts the step surface 13 . Third spring 126 then biases spacer 125 toward anchor 110 . Therefore, the lower end face 14 of the spacer 125 on the tip end side in the axial direction Da contacts the upper end face 110 a of the anchor 110 .

In this example, an example in which the third spring 126 is provided has been described, but the present invention is not limited to this, and the third spring 126 may not be provided.

A housing portion 16 is formed in the large diameter portion 11 . The accommodating portion 16 is a recess recessed from the lower end surface 14 of the spacer 125 toward the stepped surface 13 . The accommodating portion 16 accommodates the engaging portion 128 of the valve body 113 .

The inner diameter of the accommodating portion 16 is set larger than the diameter of the engaging portion 128 of the valve body 113 . Therefore, a gap is formed between the radially outer peripheral surface of the engaging portion 128 and the inner wall surface 16 a of the accommodating portion 16 .

A tapered portion 16b is formed at a portion where the inner wall surface 19 of the guide hole 18 and the inner wall surface 16a of the accommodating portion 16 are connected. That is, the inner diameter of the accommodating portion 16 on the side of the small diameter portion 12 is formed to increase continuously toward the distal end portion side in the axial direction Da. The tapered portion 16b faces the second curved surface portion 128d of the engaging portion 128. As shown in FIG. Further, the spacer 125 is biased toward the anchor 110 by the third spring 126, so that the second curved surface portion 128d of the engaging portion 128 and the tapered portion 16b of the accommodating portion 16 are brought into contact. Here, the second curved surface portion 128 d and the tapered portion 16 b are in line contact at the second contact portion 128 g of the engaging portion 128 and the contact portion 16 c of the housing portion 16 .

Here, in this example, the region A is defined by the sliding shaft portion 129, the engaging portion 128, and the tapered portion 16b, and is generally inside the second contact portion 128g and the contact portion 16c. Further, a region C is formed by the engaging portion 128, the spacer 125 and the anchor 110 and is generally surrounded by the second contact portion 128g, the contact portion 16c, the cylindrical portion 128e, the first contact portion 128f and the contact portion 110e.

A guide hole 18 is formed in the small-diameter portion 12 to indicate a through-hole on the small-diameter portion side. The guide hole 18 penetrates from the upper end face 15 , which is the end face of the spacer 125 on the rear end side in the axial direction Da, to the accommodation portion 16 . The guide hole 18 communicates with the accommodation portion 16 . A sliding shaft portion 129 of the valve body 113 is inserted into the guide hole 18 . The inner diameter of the guide hole 18 is set larger than the diameter of the sliding shaft portion 129 . The inner wall surface 19 of the guide hole 18 serves as a sliding surface that slidably supports the sliding shaft portion 129 .

Here, the anchor 110 is biased toward the fixed core 101 side by the biasing force of the second spring 124 . Therefore, the upper end surface 110 a of the anchor 110 contacts the lower end surface 14 of the spacer 125 . The biasing force of the second spring 124 is set smaller than the biasing force of the third spring 126 . Therefore, the anchor 110 is biased toward the distal end side in the axial direction Da by the third spring 126 via the spacer 125 . Thereby, the movement of the anchor 110 toward the rear end in the axial direction Da, that is, the movement in the valve opening direction is restricted by the spacer 125 and the third spring 126 .

Also, in the valve closed state, the contact portion 16c of the housing portion 16 contacts the second contact portion 128g of the engaging portion 128 of the valve body 113, so that the spacer 125 is arranged at a predetermined position (reference position). The lower end surface 14 of the spacer 125 contacts the upper end surface 110a of the anchor 110 while the spacer 125 is arranged at the reference position. Thereby, a gap G2, a so-called preliminary stroke, can be provided between the first contact portion 128f of the valve body 113 and the contact portion 110e of the anchor 110. As shown in FIG. That is, the spacer 125 forms a predetermined gap G2 between the anchor 110 and the engaging portion 128 of the valve body 113, which is the preliminary stroke.

In addition, when the valve body 113 is closed, the length (G1+G2) that is the sum of the gap G2 and the gap G1 is the gap between the tip portion 101b of the fixed core 101 and the upper end surface 110a of the anchor 110, a so-called magnetic attraction gap.

1-3. Operation Example of Fuel Injection Apparatus Next, an operation example of the fuel injection apparatus 1 having the configuration described above will be described with reference to FIGS. 2 to 6. FIG.
FIG. 3 is a cross-sectional view showing the periphery of spacer 125 when the valve opening starts, and FIG. 4 is a cross-sectional view showing the periphery of spacer 125 when the valve opening operation ends.

When the electromagnetic coil 108 is energized by the ECU, magnetic flux flows through the magnetic circuit formed by the fixed core 101 , the anchor 110 , the nozzle holder 102 and the housing 109 . Then, a magnetic attractive force that attracts the anchor 110 is generated in the fixed core 101 . When the magnetic attraction force of fixed core 101 exceeds the biasing force of third spring 126 , anchor 110 presses spacer 125 and moves toward fixed core 101 . Therefore, both the anchor 110 and the spacer 125 move toward the rear end side in the axial direction Da. During this time, the tip of the valve body 113 is in contact with the valve seat 103 a of the injection hole forming member 103 .

As the anchor 110 moves to the rear end side in the axial direction Da, the tapered portion 110b of the anchor 110 engages the first contact portion 128f of the engaging portion 128 of the valve body 113 at the contact portion 110e, as shown in FIG. Therefore, the gap G2 between the contact portion 110e of the anchor 110 and the first contact portion 128f of the engaging portion 128 is zero.

In addition, the size of the gap (magnetic attraction gap) between the anchor 110 and the fixed core 101 is reduced by the amount of movement of the anchor 110 to the rear end side in the axial direction Da, and in the example shown in FIG. 3, the magnetic attraction gap has a length of G1. Furthermore, since the spacer 125 also moves toward the rear end side in the axial direction Da, a gap G3 is generated between the contact portion 16c of the accommodating portion 16 and the second contact portion 128g of the engaging portion 128. As shown in FIG.

Also, just before starting the valve opening operation shown in FIG. Therefore, the anchor 110 comes into contact with the engaging portion 128 after moving through the gap G2. As a result, the anchor 110 accelerates until it abuts against the engaging portion 128, that is, while moving through the gap G2. As a result, the anchor 110 can be brought into contact with the engaging portion 128 while the anchor 110 is accelerated.

Thus, the force applied from the anchor 110 to the valve body 113 via the engaging portion 128 can be increased, and the valve body 113 can be quickly started to move toward the rear end side in the axial direction Da. As a result, the valve opening operation in the valve body 113 can be started quickly.

Here, in this example, the valve opening operation refers to a series of operations from the valve closed state shown in FIG. 2 to the anchor 110 and spacer 125 starting to move to the state shown in FIG. 4 (full lift). Therefore, the start of the valve opening operation means that the anchor 110 and the spacer 125 start moving. In addition, the valve opening or valve open state refers to a state in which the valve body 113 actually moves to the rear end side in the axial direction Da, the tip of the valve body 113 separates from the valve seat 103a of the injection hole forming member 103, and the injection hole 112 is opened. Therefore, the start of opening the valve means that the tip of the valve body 113 begins to separate from the valve seat 103a.

As shown in FIG. 4, when the anchor 110, the spacer 125, and the valve body 113 move further toward the rear end side in the axial direction Da, the tip of the valve body 113 separates from the valve seat 103a of the injection hole forming member 103, and the injection hole 112 is opened to open the valve. As a result, fuel is injected from the injection hole 112 .

Also, the upper end surface 110a of the anchor 110 abuts against the distal end portion 101b of the fixed core 101, thereby restricting the movement of the anchor 110 toward the rear end side in the axial direction Da. In addition, the valve body 113 moves toward the rear end side in the axial direction Da by inertia force, but is pushed back by the biasing force of the first spring 118 . Therefore, the valve body 113 stops with the first contact portion 128f of the engaging portion 128 contacting the contact portion 110e of the anchor 110, as shown in FIG. As a result, the valve body 113 is moved by a predetermined stroke amount (gap G1 shown in FIG. 2), and the valve is opened and stationary.

In the valve open stationary state, the anchor 110 is attracted to the fixed core 101 by magnetic attraction force, and the valve member 104 is biased in the valve closing direction by the biasing force of the first spring 118 . Therefore, the anchor 110 and the valve body 113 are in contact with each other and integrated. That is, the first contact portion 128f of the engaging portion 128 of the valve body 113 contacts the contact portion 110e of the anchor 110, and the size of the gap G2 becomes zero.

Furthermore, since the biasing force of the third spring 126 is smaller than the magnetic attraction force, the third spring 126 cannot push back the anchor 110 toward the tip side in the axial direction Da via the spacer 125 . Therefore, the lower end surface 14 of the spacer 125 contacts the upper end surface 110a of the anchor 110, and the gap G3 between the second contact portion 128g of the engaging portion 128 and the contact portion 16c of the accommodating portion 16 of the spacer 125 is maintained. Furthermore, since the anchor 110 is in contact with the fixed core 101, the size of the gap G1 between the upper end surface 110a of the anchor 110 and the tip portion 101b of the fixed core 101 is zero.

When the drive pulse is turned off in the valve open state (full lift state) shown in FIG. 4, the energization to the electromagnetic coil 108 is cut off. Therefore, the magnetic attractive force generated between the anchor 110 and the fixed core 101 disappears. Then, when the magnetic attraction force becomes smaller than the biasing force of the first spring 118, the valve member 104 starts to move toward the distal end side in the axial direction Da, that is, in the valve closing direction. The valve member 104, which has started to move in the valve closing direction, is displaced integrally with the anchor 110, and after being displaced by a length G1, the tip of the valve body 113 is seated on the valve seat 103a. As a result, the valve is returned to the closed state shown in FIG. 2, and the injection of fuel by the fuel injection device 1 is stopped.

Here, an operation example of a conventional fuel injection device will be described with reference to FIGS. 5 to 7. FIG. Parts common to those of the fuel injection device 1 of this embodiment are denoted by the same reference numerals, and overlapping descriptions are omitted. 5 to 7 are cross-sectional views enlarging the surroundings of a spacer in a conventional fuel injection device. 5 shows the closed state, FIG. 6 shows the state when the valve starts to open, and FIG. 7 shows the state after the valve opening operation is completed.

When the electromagnetic coil 108 is energized in the valve closed state shown in FIG. At this time, the volume of the region A formed by the upper end surface 328a of the engaging portion 328, the sliding shaft portion 329 of the valve body 313, and the chamfered portion 216c of the housing portion 216 of the spacer 225 increases sharply as the spacer 225 moves. Therefore, the fuel (fluid) around the spacer 225 tries to flow into the region A. Furthermore, since the volume of the gap formed between the upper surface portion 216b of the accommodating portion 216 and the upper end surface 328a of the engaging portion 328 also increases, the fluid tends to flow into this gap as well.

However, as shown in FIG. 6, in the conventional fuel injection device, the area A is surrounded by the spacer 225, the engaging portion 328 and the sliding shaft portion 329. Therefore, the fluid cannot flow in at a sufficient flow rate, and the volume of this area A increases, thereby reducing the pressure in this area.

There are minute gaps between the sliding shaft portion 329 and the inner wall surface 219 of the guide hole 218 and between the shaft portion 313 a and the insertion hole 310 c of the anchor 310 . However, the amount of fluid that can suppress the pressure drop in the low-pressure portion cannot flow through this gap.

Furthermore, as the spacer 225 and the anchor 310 move to the rear end side in the axial direction Da, the volume of the gap formed between the upper surface portion 216b of the housing portion 216 and the upper end surface 328a of the engaging portion 328 also increases, so the fluid also tries to flow into this gap. However, the speed at which the gap formed between the upper surface portion 216b and the upper end surface 328a widens is faster than the inflow speed of the fluid, and the gap is narrow, so the fluid cannot flow in sufficiently. Therefore, the pressure in the gap between the upper surface portion 216b and the upper end surface 328a is reduced. Then, a large fluid force called sticking force acts on the spacer 225 toward the distal end side in the axial direction Da.

In this way, the spacer 225 is subjected to a force caused by pressure fluctuations in the area A and the gap between the upper surface portion 216b and the upper end surface 328a. Note that not only the pressure of the low-pressure portion including the region A but also the force generated by the shearing of the fuel (fluid) flowing around the spacer 225 acts on the spacer 225 . Here, pressure and fluid shear force are collectively referred to as fluid force. However, the fluid force acting on the spacer 225 is dominated by the pressure of the low pressure portion including the region A rather than the shear force of the fluid.

Also, as shown in FIG. 6, when the valve is opened, that is, when the anchor 310 and the valve body 313 are displaced, the upper end surface 310a of the anchor 310 contacts the lower end surface 328b of the engaging portion 328, and the anchor 310 and the engaging portion 328 are engaged. At this time, the volume of region B (FIGS. 5 and 6) formed by the shaft portion 313a of the valve body 313, the lower end surface 328b of the engaging portion 328, and the upper end surface 310a of the anchor 310 is compressed, so the pressure increases. Due to the action of this positive pressure, a large fluid force acts on the anchor 310 toward the distal end side in the axial direction Da. In particular, when the gap between the lower end surface 328b of the engaging portion 328 and the upper end surface 310a of the anchor 310 becomes narrower, the fluid is pushed out through the narrow gap. Therefore, a large fluid resistance force called squeeze force is generated in the valve body 313 and the anchor 310 . That is, a large fluid force called squeeze force acts on the anchor 310 toward the distal end in the axial direction Da.

Note that there is a minute gap between the shaft portion 313a and the insertion hole 310c of the anchor 310. However, the amount of fluid that can suppress the pressure increase in region B cannot flow out from this gap.

In this way, a large fluid force acts on the spacer 225 and the anchor 310 toward the tip side in the axial direction Da, that is, in the direction that hinders the valve opening operation, due to the negative pressure acting on the area A, the sticking force acting on the upper surface portion 216b and the upper end surface 328a, the positive pressure acting on the area B, and the squeeze force acting on the lower end surface 328b and the upper end surface 310a. Therefore, this fluid force hindered the responsiveness of opening the valve. In addition, since the fluid force is large, it is susceptible to manufacturing variations in the dimensions of the sliding parts and each part, resulting in variations in the valve opening operation and, as a result, variations in the injection amount for each unit. Furthermore, the need to generate a magnetic attraction force that overcomes this fluid force has also been a factor in the injection amount variation.

When the valve is in the open state (full lift state), as shown in FIG. 7, the anchor 310 contacts the engaging portion 328 of the valve body 313, and a gap G3 is formed between the upper end surface 328a of the engaging portion 328 and the upper surface portion 216b of the housing portion 216 of the spacer 225. When the valve is displaced from the open state shown in FIG. 7 to the closed state, the volume of the area A or the gap between the upper surface portion 216b and the upper end surface 328a decreases, so the pressure increases, and a squeezing force acts on the upper surface portion 216b and the upper end surface 328a.

In addition, since the volume of the area B and the gap between the lower end surface 328b and the upper end surface 310a increases, the pressure decreases and sticking force is generated between the lower end surface 328b and the upper end surface 310a. As a result, a fluid force acts on the spacer 225 and the anchor 310 in a direction that prevents the valve from closing, that is, toward the rear end side in the axial direction Da.

On the other hand, in the fuel injection device 1 of this example, as shown in FIG. 2, a second curved surface portion 128d is provided on the rear end side of the engaging portion 128 of the valve body 113 in the axial direction Da, and the accommodating portion 16 of the spacer 125 is provided with a tapered portion 16b. The second curved surface portion 128d and the tapered portion 16b are in line contact with each other at the second contact portion 128g and the contact portion 16c, respectively. As a result, at the start of the valve opening operation as shown in FIG. 2, the fluid force at the start of the valve opening operation can be reduced and the responsiveness can be enhanced mainly by the following two effects.

First, the first effect is that the resistance of the fluid flowing from area C to area A can be reduced. In the conventional example shown in FIGS. 5 to 7, the gap between the upper surface portion 216b and the upper end surface 328a serves as the flow path. When a negative pressure is generated in the area A, the fluid flows from the area C into the gap between the upper surface portion 216b and the upper end surface 328a, or flows out from the gap between the upper surface portion 216b and the upper end surface 328a into the area A. Therefore, when the gap between the upper surface portion 216b and the upper end surface 328a is considered as a channel, an inlet loss and an outlet loss occur, and the fluid resistance increases.

In addition, since the gap between the upper surface portion 216b and the upper end surface 328a is also narrow, the pipe friction loss in the flow passage increases. Therefore, the pressure loss when the fluid flows from area C to area A increases, and the magnitude of the negative pressure in area A increases.

On the other hand, in this example, when the fluid flows from region C to region A, the provision of the tapered portion 16b in the accommodating portion 16 allows the size of the flow path to be changed gradually, so the above-described inlet loss and outlet loss can be reduced.

In addition, since the second curved surface portion 128d and the tapered portion 16b are in line contact, the flow path resistance between the engaging portion 128 and the

contact portions

128g and 16c of the housing portion 16 is smaller than in the conventional example. Therefore, in this example, the resistance when the fluid flows from the area C to the area A can be reduced, and the negative pressure in the area A is alleviated. As a result, since the negative pressure can be reduced, the fluid force acting on the spacer 125 toward the distal end side in the axial direction Da can be reduced.

Next, the second effect is a reduction in sticking force. In the conventional example shown in FIGS. 5 to 7, the contact portion between the upper surface portion 216b and the upper end surface 328a is flat and is in surface contact. Therefore, a large sticking force is generated between the upper surface portion 216b and the upper end surface 328a.

On the other hand, the abutting

portions

128f and 128g of this example are formed on the

curved surface portions

128c and 128d, and are in line contact with the anchor 110 and the housing portion 16. Therefore, the sticking force is small because the fluid flows in and out easily. As a result, the fluid force acting on the spacer 125 toward the distal end in the axial direction Da becomes smaller.

For the above reasons, in this example, the fluid force at the start of the valve opening operation can be reduced and the responsiveness can be improved. As a result, variations in the valve opening operation can be reduced, and variations in the injection amount can be reduced.

Also, as shown in FIG. 3, just before the valve opens or when the valve starts to open, the fluid force can be similarly reduced by two effects, and the responsiveness can be improved. 5 to 7, the upper end surface 310a of the anchor 310 and the lower end surface 328b of the engaging portion 328 form a flow path, which rapidly contracts and expands, and the flow path formed between the flat surfaces is narrow. Therefore, the inlet loss, the outlet loss, and the tube friction loss are large, the fluid resistance when flowing from the region B to the region C is large, and the pressure in the region B becomes high.

On the other hand, in this example, just before the valve opens or when the valve starts to open, the engaging portion 128 and the anchor 110 are in line contact with the first contact portion 128f of the first curved surface portion 128c and the contact portion 110e of the tapered portion 110b. Therefore, inlet loss, outlet loss, and pipe friction loss are small, and fluid resistance when flowing from region B to region C can be reduced. As a result, the high pressure in the region B is relaxed, that is, the positive pressure can be made smaller than in the conventional example. That is, in this example, the tapered portion 110b of the anchor and the first curved surface portion 128c of the engaging portion 128 constitute the fluid resistance reducing portion.

Also, by making the engaging portion 128 and the anchor 110 in line contact, the fluid can easily flow in and out, so the squeezing force can be reduced. As a result, the fluid force acting on the anchor 110 toward the distal end side in the axial direction Da is reduced, and variations in the valve opening operation can be reduced, and variations in the injection amount can be reduced.

In this example, the engaging portion 128 has a second curved surface portion 128d on the rear end side in the axial direction Da and a first curved surface portion 128c on the front end side in the axial direction Da, both of which are in line contact with the spacer 125 and the anchor 110, respectively. These two line contact portions have different roles during the valve opening operation. That is, the line contact at the second curved surface portion 128d on the rear end side in the axial direction Da reduces the fluid force at the start of the valve opening operation as shown in FIG. On the other hand, the first curved surface portion 128c on the tip side in the axial direction Da reduces the fluid force immediately before the valve opens or when the valve starts to open, as shown in FIG. Therefore, in order to obtain a greater effect, it is desirable to provide line contact portions on both sides of the engaging portion 128 .

In addition, in this example, an example in which curved surface portions are provided on both sides of the engaging portion 128 and both sides are in line contact has been described, but the present invention is not limited to this. For example, only one of the engaging portions 128 may be provided with a curved portion so that only one side is in line contact. Note that the speed of the anchor 110 and the spacer 125 is higher immediately before the valve opening or at the start of the valve opening than at the start of the valve opening operation. Therefore, the fluid force reduction effect is greater at the line contact portion of the first curved surface portion 128c on the tip side in the axial direction Da.

Further, according to the fuel injection device 1 of this embodiment, the fluid force can be reduced and the responsiveness can be improved when the valve is closed as well as when the valve is opened. When the valve is closed, region B has a relatively negative pressure and region A has a relatively positive pressure. On the other hand, the negative pressure acting on area B, the sticking force acting on the anchor 110 and the engaging portion 128, the positive pressure acting on the area A, and the squeezing force acting on the spacer 125 and the engaging portion 128 can be reduced in the same manner as when the valve is opened.

Also, the spacer 125 and the anchor 110 are provided with tapered

portions

110b and 16c, which are in line contact with the engaging portion 128 of the valve body 113. Therefore, the central axis of the spacer 125 or the anchor 110 and the central axis of the valve body 113 can be aligned. Therefore, the axial centers of the spacer 125 and the valve body 113 and between the anchor 110 and the valve body 113 can be aligned during the valve closing operation, the valve opening operation, and the valve closing operation. As a result, variations in operation of the spacers 125 and the anchors 110 can be reduced, and variations in the injection amount can be reduced.

Also, an example in which the sliding shaft portion 129 is formed closer to the rear end portion in the axial direction Da than the engaging portion 128 and slides on the spacer 125 has been described, but it is not limited to this. For example, the valve body 113 and the spacer 125 may slide on the cylindrical portion 128e and the inner wall surface 16a. Furthermore, in this example, an example in which the spacer 125 has the small diameter portion 12 has been described, but the spacer may not have the small diameter portion 12 .

2. Second Embodiment Next, a fuel injection device according to a second embodiment will be described with reference to FIG.
FIG. 8 is an enlarged cross-sectional view showing the periphery of the spacer in the fuel injection device according to the second embodiment.

The fuel injection device according to the second embodiment differs from the fuel injection device 1 according to the first embodiment in the shapes of anchors and spacers. Therefore, here, the parts common to the fuel injection device 1 according to the first embodiment are denoted by the same reference numerals, and overlapping explanations are omitted.

As shown in FIG. 8, the spacer 125A has the same shape as the spacer 225 according to the conventional example shown in FIG.

A stepped portion 110f is formed on the upper end surface 110a of the anchor 110A. The stepped portion 110f is a concave portion recessed from the upper end surface 110a toward the tip side in the axial direction Da. The stepped portion 110f is formed on a concentric circle between the tapered portion 110b and the insertion hole 110c. The stepped portion 110f continues to the tapered portion 110b.

In the case of the fuel injection device according to the second embodiment, the fluid flows from area B to area C and then to area A as soon as the valve opening operation is started. Further, by providing the step portion 110f in the anchor 110A, when the fluid flows from the area B to the area C, the direction of the fluid flow is changed to the direction indicated by the arrow E, that is, the direction in which the spacer 125 opens the valve. Therefore, a force acts on the spacer 125 in the valve opening direction from the diverted fluid. As a result, according to the fuel injection device according to the second embodiment, the valve opening responsiveness can be enhanced, and variations in the valve opening operation and variations in the injection amount can be reduced.

The rest of the configuration is the same as the fuel injection device 1 according to the first embodiment, so description thereof will be omitted. A fuel injection device having such spacers 125A and anchors 110A can also provide the same effects as the fuel injection device 1 according to the first embodiment described above.

3. Third Embodiment Next, a fuel injection device according to a third embodiment will be described with reference to FIG.
FIG. 9 is an enlarged cross-sectional view showing the periphery of the spacer in the fuel injection device according to the third embodiment.

The fuel injection device according to the third embodiment differs from the fuel injection device 1 according to the first embodiment in the shape of the spacer and the tapered portion of the spacer. Therefore, here, the parts common to the fuel injection device 1 according to the first embodiment are denoted by the same reference numerals, and overlapping explanations are omitted.

As shown in FIG. 9, a tapered portion 110b provided on the anchor 110 is inclined toward a tapered portion 16b of a spacer 125B, which will be described later. Therefore, during the valve opening operation, the fluid flowing through the contact portion 110e and the first contact portion 128f of the tapered portion 110b flows in the direction of the arrow E, that is, toward the tapered portion 16b of the spacer 125B.

Also, the tapered portion 16b of the spacer 125B is formed up to the vicinity of the lower end surface 14 of the spacer 125B. That is, the tapered portion 16b is arranged on the extension of the tapered portion 110b of the anchor 110 in the direction of inclination. Accordingly, the fluid flowing along the tapered portion 110b of the anchor 110 can be received by the tapered portion 16b of the spacer 125B. As a result, as in the case of the fuel injection device according to the second embodiment, a fluid flow force acts in the direction in which the spacer 125B opens the valve, so that the valve opening responsiveness can be enhanced, and variations in the valve opening operation and in the injection amount can be reduced.

The rest of the configuration is the same as the fuel injection device 1 according to the first embodiment, so description thereof will be omitted. A fuel injection device having such a spacer 125B can also provide the same effects as the fuel injection device 1 according to the first embodiment described above.

4. Fourth Embodiment Next, a fuel injection device according to a fourth embodiment will be described with reference to FIG.
FIG. 10 is an enlarged cross-sectional view showing the periphery of the spacer in the fuel injection device according to the fourth embodiment.

The fuel injection device according to the fourth embodiment differs from the fuel injection device 1 according to the first embodiment in the shape of the engaging portion. Therefore, here, the parts common to the fuel injection device 1 according to the first embodiment are denoted by the same reference numerals, and overlapping explanations are omitted.

As shown in FIG. 10, the anchors 110 and spacers 125 of the fuel injection device according to the fourth embodiment have the same shapes as the anchors 310 and spacers 225 of the conventional fuel injection device shown in FIG. The shapes of the anchors 110 and the spacers 125 may be the shapes of the anchors and spacers according to the first to third embodiments described above.

As shown in FIG. 10, an engaging portion 128 is provided on the valve body 113C. A concave portion 128h is formed in a surface of the engaging portion 128 facing the upper end surface 110a of the anchor 110. As shown in FIG. The recessed portion 128h is recessed in a curved shape from the lower end surface of the engaging portion 128 toward the axial direction Da. Therefore, the first contact portion 128f of the engaging portion 128 and the contact portion 110e of the anchor 110 are in line contact. As a result, sticking force and squeezing force can be reduced, fluid force during opening/closing valve operation can be reduced, and responsiveness can be improved, as in the case of the fuel injection device 1 according to the first embodiment.

The rest of the configuration is the same as the fuel injection device 1 according to the first embodiment, so description thereof will be omitted. A fuel injection device having such a valve body 113C can also provide the same effects as the fuel injection device 1 according to the first embodiment described above.

5. Fifth Embodiment Next, a fuel injection device according to a fifth embodiment will be described with reference to FIG.
FIG. 11 is an enlarged cross-sectional view showing the periphery of the spacer in the fuel injection device according to the fifth embodiment.

The fuel injection device according to the fifth embodiment differs from the fuel injection device 1 according to the first embodiment in the shape of the tapered portion of the anchor. Therefore, here, the parts common to the fuel injection device 1 according to the first embodiment are denoted by the same reference numerals, and overlapping explanations are omitted.

As shown in FIG. 11, a plurality of grooves 110g are formed in the tapered portion 110b of the anchor 110D. The grooves 110g are radially formed in the tapered portion 110b. That is, the groove 110g is formed continuously from the insertion hole 110c to the upper end surface 110a. By passing the fluid through the groove 110g, the fluid resistance of the fluid flowing from the area B to the area C or from the area C to the area B can be reduced during the opening/closing operation of the valve.

The rest of the configuration is the same as the fuel injection device 1 according to the first embodiment, so description thereof will be omitted. A fuel injection device having such an anchor 110D can also provide the same effects as the fuel injection device 1 according to the first embodiment described above.

In addition, in the fuel injection device according to the fifth embodiment, an example in which the groove 110g is formed in the anchor 110D has been described, but the present invention is not limited to this. For example, grooves may be formed in the first curved surface portion 128c of the engaging portion 128 . That is, it is sufficient that at least one of the first contact portion 128f of the engaging portion 128 and the contact portion 110e of the anchor 110D has a groove.

6. Sixth Embodiment Next, a fuel injection device according to a sixth embodiment will be described with reference to FIG.
FIG. 12 is an enlarged cross-sectional view showing the periphery of the spacer in the fuel injection device according to the sixth embodiment.

The fuel injection device according to the sixth embodiment differs from the fuel injection device 1 according to the first embodiment in the shape of the engaging portion of the valve body. Therefore, here, the parts common to the fuel injection device 1 according to the first embodiment are denoted by the same reference numerals, and overlapping explanations are omitted.

As shown in FIG. 12, the anchors 110 and spacers 125 of the fuel injection device according to the sixth embodiment have the same shapes as the anchors 310 and spacers 225 of the conventional fuel injection device shown in FIG. The shapes of the anchors 110 and the spacers 125 may be the shapes of the anchors and spacers according to the first to fifth embodiments described above.

As shown in FIG. 12, an engaging portion 128 is formed on the valve body 113E. A plurality of grooves 128i are formed in a lower end surface 128b of the engaging portion 128 facing the upper end surface 110a of the anchor 110. As shown in FIG. The grooves 128i are radially formed in the lower end surface 128b. The groove 128 i is formed in a region where the engaging portion 128 contacts the upper end surface 110 a of the anchor 110 . Since the fluid passes through the groove 128i during the opening/closing operation of the valve, the fluid resistance of the fluid flowing from the area B to the area C or from the area C to the area B can be reduced. That is, in the fuel injection device according to the sixth embodiment, the groove 128i formed in the engaging portion 128 constitutes the fluid resistance reducing portion.

Although an example in which the groove, which is the fluid resistance reduction portion, is provided on the engaging portion 128 has been described, the present invention is not limited to this, and may be provided on the surface of the anchor 110 facing the engaging portion 128 . That is, the groove should be formed in at least one of the engaging portion 128 and the anchor 110 .

The rest of the configuration is the same as the fuel injection device 1 according to the first embodiment, so description thereof will be omitted. A fuel injection device having such a valve body 113E can also provide the same effects as the fuel injection device 1 according to the first embodiment described above.

It should be noted that the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications are possible without departing from the gist of the invention described in the claims.

In addition, in the above-described embodiment, an example in which the engaging portion and the anchor and the engaging portion and the spacer are in line contact has been described, but the present invention is not limited to this, and the engaging portion and the anchor or the engaging portion and the spacer may be in point contact.

Although the terms "parallel" and "perpendicular" are used in this specification, they do not mean strictly "parallel" and "perpendicular" only.

1... Fuel injection device 11... Large diameter part 12... Small diameter part 13... Stepped surface 14... Lower end face 15... Upper end face 16... Accommodating part 16a... Inner wall surface 16b... Taper part 16c... Contact part 18... Guide hole (small diameter side through hole) 19... Inner wall surface 101... Fixed core 101a... Through hole 10 1b... Tip part 102... Nozzle holder 102c... Communication hole 103... Injection hole forming member 103a... Valve seat 104... Valve member 105... Guide member 108... Electromagnetic coil 109...

Housing

110, 110A, 110D... Anchor 110a... Upper end face 110b... Taper part 110c... Insertion hole 1 10e... Contact portion 110f... Stepped portion 110g... Groove 111... Fuel supply port 112...

Injection hole

113, 113C, 113E... Valve body 113a... Shaft part 113b... Connection recess 118... First spring 119... Adjusting member 124...

Second spring

125, 125A, 125B... Spacer 126... Third spring 127... Rod head 127a... Connecting convex part 128... Engaging part 128a... Upper end face 128b... Lower end face 128c... First curved surface part 128d... Second curved surface part 128e... Cylindrical part 128f... First contact part 128g... Second contact part 128i... Groove (fluid resistance reducing part),　129...Sliding shaft part

Claims

a nozzle holder provided with an injection hole forming member;
a fixed core disposed in the nozzle holder;
an anchor arranged opposite to the fixed core;
a valve member movably arranged in the nozzle holder,
The valve member is
a valve body provided with a shaft portion for opening and closing the injection hole provided in the injection hole forming member and an engaging portion that engages with the anchor during a valve opening operation;
a spacer that has an accommodating portion in which the engaging portion is accommodated and that forms a predetermined gap between the engaging portion and the anchor when the valve is closed;
A fuel injection device, wherein a fluid resistance reducing portion that reduces fluid resistance is provided between the engaging portion and the anchor.
The fuel injection device according to claim 1, wherein the engaging portion and the anchor are in point contact or line contact, and the fluid resistance reducing portion is formed by a portion where the engaging portion and the anchor contact.
The fuel injection device according to claim 2, wherein the engaging portion and the spacer are in point contact or line contact.
The fuel injection device according to claim 2, wherein a curved surface portion is formed on a surface of the engaging portion that faces the anchor.
5. The fuel injection device according to claim 4, wherein a portion of the anchor that contacts the engaging portion is provided with a tapered portion.
The anchor is formed with a stepped portion continuous with the tapered portion,
6. The fuel injection device according to claim 5, wherein the tapered portion and the stepped portion turn the flow direction of the fluid toward the spacer.
The fuel injection device according to claim 5, wherein a groove through which the fluid passes is formed in the tapered portion.
6. The fuel injection device according to claim 5, wherein a taper portion formed in a tapered shape is provided at a portion of the spacer that contacts the engaging portion.
9. The fuel injection device according to claim 8, wherein the tapered portion formed in the spacer is arranged on an extension of the tapered portion formed in the anchor in the direction of inclination.
2. The fuel injection device according to claim 1, wherein the fluid resistance reduction portion is a groove provided on surfaces facing each other in at least one of the engaging portion and the anchor.