WO2018066327A1 - Fuel injection valve - Google Patents

Abstract

The objective of the present invention is to achieve an inward-opening valve structure with a simple configuration in a fuel injection valve equipped with a drive element that extends in response to applied voltage. Therefore, this fuel injection valve is equipped with: a valve body 1 having an upstream seat part 1a arranged on the upstream side in the axial direction and a downstream seat part 1b arranged on the downstream side in the axial direction; an upstream valve seat 7a that closes an upstream fuel passage when contacted by the upstream seat part 1a; a downstream valve seat 2c that closes a downstream fuel passage when contacted by the downstream seat part 1b; a biasing member 4 that biases the valve body 1 in the direction in which the upstream seat part 1a contacts the upstream valve seat 7a; and a drive element 11 that drives the valve body 1 in the direction in which the downstream seat part 1b contacts the downstream valve seat 2c. When the upstream seat part 1a is separated from the upstream valve seat 7a and the downstream seat part 1b is separated from the downstream valve seat 2c, the valve body 1 is driven by the drive element 11 and injects fuel.

Description

Fuel injection valve

The present invention relates to a fuel injection valve used in an internal combustion engine, which has a piezoelectric element whose full length is extended by application of voltage, and which opens and closes the valve body by expansion and contraction of the full length of the piezoelectric element.

Japanese Patent Application Laid-Open No. 2002-31010 (Patent Document 1) discloses that the expansion of a piezoelectric element is directly transmitted to a valve body by the start of energization, and when the valve body is pushed, the tip of the valve body is separated from the valve seat, A fuel injection valve that opens a flow path and injects fuel is described. When the energization is completed, the fuel injection valve is pulled back by the force of a spring that urges the valve element to come into contact with the valve seat, and the fuel injection is ended by closing the fuel flow path.

JP 2002-31010 A

In the fuel injection valve of Patent Document 1, since the piezoelectric element has a structure that expands when a voltage is applied, when the valve element is directly operated, the valve element is pushed by applying a voltage. Such a fuel injection valve has a structure in which fuel is injected from a gap formed between the valve body and the valve seat by pushing out the valve body. That is, such a fuel injection valve has an outwardly opening valve structure in which a valve body is displaced toward the outside of the fuel injection valve by application of a voltage, thereby opening a fuel passage. In the outwardly opening valve structure, the shape of the tip portion in contact with the valve seat of the valve body is generally a conical shape, and the generated spray is an umbrella-shaped spray. A commonly used electromagnetic fuel injection valve is a fuel passage between a valve body and a valve seat, which is energized to lift the valve body directly and displace the valve body toward the inside of the fuel injection valve. It has an internal opening valve structure. In such a fuel injection valve, a spray shape can be made into a desired shape by providing a plurality of injection holes and injecting fuel. On the other hand, in the outwardly opened valve structure, the shape and number of the valve bodies are restricted, the degree of freedom of the spray shape is small, and the improvement of the combustion performance is limited.

An object of the present invention is to realize an inwardly opening valve structure with a simple mechanism in a fuel injection valve having a drive element that expands when a voltage is applied, and to optimize various force relationships acting on the valve body. It is to provide a set fuel injection valve.

In order to achieve the above object, the fuel injection valve of the present invention comprises:
A valve body configured to be displaceable in the axial direction and having an upstream seat portion disposed on the upstream side in the fuel flow direction in the axial direction and a downstream seat portion disposed on the downstream side;
An upstream valve seat in which the upstream fuel passage is closed by contacting the upstream seat portion, and the upstream fuel passage is opened by separating the upstream seat portion;
A downstream valve seat in which the downstream fuel passage is closed by contacting the downstream seat portion and the downstream fuel passage is opened by separating the downstream seat portion; and
An urging member that urges the valve body in a direction in which the upstream seat portion contacts the upstream valve seat;
A driving element that drives the valve body in a direction in which the downstream seat portion contacts the downstream valve seat;
With
The valve element is driven by the drive element to inject fuel in a state where the upstream seat portion is separated from the upstream valve seat and the downstream seat portion is separated from the downstream valve seat.

According to the present invention, it is possible to realize an inwardly opening valve structure with a simple mechanism. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is sectional drawing which shows the structure of the fuel injection valve which concerns on one Example of this invention. It is an expanded sectional view which expands and shows the vicinity of the downstream sheet | seat part 1b (B section of FIG. 1) of FIG. It is an expanded sectional view which expands and shows the vicinity of the upstream sheet | seat part 1a (A part of FIG. 1) of FIG. It is an expanded sectional view which expands and shows the vicinity of the bellows body 8 of FIG. It is an expanded sectional view which expands and shows the vicinity of the damper body 12 of FIG. It is the expanded sectional view which showed the state of the upstream sheet | seat part 1a in each conditions. It is the expanded sectional view which showed the state of the downstream sheet | seat part 1b in each condition. It is a figure which shows the relationship between the applied voltage of the fuel injection valve 100 which concerns on this invention, and the contact state with each valve seat of the upstream seat part 1a and the downstream seat part 1b. It is a figure which shows the contact state with each valve seat of the upstream seat part 1a and the downstream seat part 1b shown to FIG. 8A. It is the figure which showed the force relationship which acts on the valve body 1 of the fuel injection valve 100 which concerns on this invention. It is the figure which showed the detail of the assembly method of the bellows body 8 of the fuel injection valve 100 which concerns on this invention. 3 is a detailed cross-sectional view of the valve body 1 and the nozzle body 3 of the fuel injection valve 100 according to the present invention. FIG. 1 is an overall view of a fuel injection valve according to the present embodiment. The cross-sectional enlarged view of the valve body drive mechanism of a present Example is shown. The three-dimensional shape figure of the valve body drive mechanism of a present Example is shown. It is a figure for demonstrating operation | movement of the valve body drive mechanism of a present Example. The figure which used the piezoelectric element as a drive element is shown. The whole figure of the flow control valve of the example of the present invention is shown. It is a figure which shows the detail of the valve body drive mechanism using the drive element of the Example of this invention.

Embodiments of a fuel injection valve in which the structure of the present invention is often used will be described below with reference to the drawings.
[Example 1]
FIG. 1 is a cross-sectional view showing a configuration of a fuel injection valve 100 according to an embodiment of the present invention. 2 is an enlarged cross-sectional view showing the vicinity of the downstream sheet portion 1b (B portion in FIG. 1) in FIG. 1 in an enlarged manner. FIG. 3 is an enlarged cross-sectional view showing the vicinity of the upstream sheet portion 1a (A portion in FIG. 1) in FIG. 1 in an enlarged manner. FIG. 4 is an enlarged sectional view showing the vicinity of the bellows body 8 of FIG. FIG. 5 is an enlarged sectional view showing the vicinity of the damper body 12 of FIG. 1 in an enlarged manner.

A configuration of a fuel injection valve 100 according to an embodiment of the present invention will be described with reference to FIG.
In the following description, the upstream side and the downstream side represent the upstream side and the downstream side in the fuel flow direction. The end of the fuel injection valve 100 on the side where the injection hole 2b is provided is referred to as a distal end (end on the distal end), and the end opposite to the distal end is the proximal end (the proximal end). Part). The distal end is the downstream end, and the proximal end is the upstream end. Moreover, the up-down direction used in description is defined based on FIG. That is, the proximal end is above the distal end and the distal end is below the proximal end. This vertical direction is defined for the sake of simplicity of explanation, and is not related to the vertical direction in the mounted state of the fuel injection valve 100.

A downstream valve seat member (tip valve seat member) 2 is joined coaxially with the nozzle body 3 on the downstream side (front end side or internal combustion engine side) of the nozzle body 3. The valve body 1 is disposed on the upstream side of the downstream valve seat member 2. The valve body 1 is included in the nozzle body 3 and is disposed coaxially with the nozzle body 3. The valve body 1 is provided so as to be movable in the direction along the central axis 100 </ b> A of the nozzle body 3 inside the nozzle body 3. That is, the valve body 1 is configured to be displaceable in the axial direction.
Further, the valve body 1 has an upstream seat portion 1a disposed on the upstream side in the fuel flow direction in the axial direction, and a downstream seat portion 1b disposed on the downstream side. The central axis of the nozzle body 3 coincides with the central axis 100A of the fuel injection valve 100, and is configured coaxially with the central axis 100A.

Between the nozzle body 3 and the valve body 1, the 1st biasing member 4 which urges | biases the valve body 1 toward an upstream (base end side) is installed. That is, the first urging member 4 urges the valve body 1 in a direction in which the upstream seat portion 1a contacts the upstream valve seat 7a. In the case of the present embodiment, the first biasing member 4 is constituted by a coil spring. A bellows body (seal body) 8 for sealing the fuel is provided on the upstream side of the valve body 1. A drive element 11 is provided on the upstream side of the bellows body 8 so as to be positioned coaxially with the valve body 1 and the bellows body 8. That is, the drive element 11 is provided on the side opposite to the side on which the downstream sheet portion 1b is provided with respect to the upstream sheet portion 1a. The space in which the drive element 11 is accommodated is sealed by the bellows body 8, and the drive element 11 is shielded from the fuel.

A damper body 12 for canceling the linear expansion of the components is disposed upstream of the drive element 11. A fixing component 14 that fixes the position of the damper body 12 is disposed on the upstream side of the damper body 12. A casing body 16 is provided on the outer periphery of the driving element 11 and the bellows body 8, and the driving element 11 and the bellows body 8 are included in the casing body 16. The casing body 16 has a double circular pipe structure, and a fuel passage is formed in a gap formed by the double circular pipe (a gap between the inner circular pipe and the outer circular pipe). The upper casing 13 is joined to the upstream side of the casing body 16.

The fuel is supplied from the fuel supply port 13 a of the upper casing 13, passes through the fuel passage of the casing body 16, and reaches the upstream seat portion 1 a of the valve body 1. The fuel that has passed through the upstream seat portion 1 a flows through the gap between the valve body 1 and the nozzle body 3 and reaches the downstream seat portion 1 b of the valve body 1.
The fuel that has passed through the downstream seat portion 1b is injected from the nozzle hole 2b to the outside of the fuel injection valve 100, for example, an internal combustion engine, and a fuel spray FS is generated.

Next, the structure of each part will be described in detail.

The downstream valve seat member 2 has a downstream valve seat 2c and an injection hole 2b. The nozzle hole 2b is provided on the downstream side of the downstream valve seat 2c. When the downstream seat portion 1b of the valve body 1 contacts the downstream valve seat 2c, the fuel passage between the downstream valve seat 2c and the downstream seat portion 1b is closed and closed, and the downstream valve seat is closed. By separating the downstream seat portion 1b from 2c, the fuel passage between the downstream valve seat 2c and the downstream seat portion 1b is opened and opened. Thus, the downstream seat part 1b comprises the contact part contact | abutted to the downstream valve seat 2c. The downstream fuel passage is closed when the downstream seat portion 1b contacts the downstream valve seat 2c, and the downstream fuel passage is opened when the downstream seat portion 1b is separated from the downstream valve seat 2c.

When the downstream seat portion 1b is separated from the downstream valve seat 2c, the fuel flowing down the fuel passage between the downstream valve seat 2c and the downstream seat portion 1b is injected from the injection hole 2b. At this time, the shape (shape, cross-sectional area, length, etc.) and number of the injection holes 2b are determined so that the injected fuel can form a desired spray. The downstream valve seat member 2 in which the injection hole 2b is formed is a component for forming the required spray.

The downstream valve seat member 2 is inserted and fixed on the inner peripheral side of the downstream end of the nozzle body 3. The downstream valve seat member 2 has a spherical convex portion 2d on the outer surface side of the downstream end portion, and has an inner surface 2e formed in a conical surface or a spherical surface on the inner side. The downstream valve seat 2 c is formed on the inner surface 2 e of the downstream valve seat member 2.

One or more nozzle holes 2b for injecting fuel are opened at the positions of the spherical convex portions 2d.
The nozzle hole 2b penetrates from the outer surface of the spherical convex portion 2d to the inner conical surface or spherical surface 2e. The nozzle hole 2b may be formed with a single diameter in the direction of the central axis 2bA, or may be formed with a stepped shape in which a plurality of holes having different diameters are connected in the direction of the central axis 2bA. The nozzle hole 2b of the present embodiment has a shape in which two holes are connected, and the diameter of the downstream hole is larger than the diameter of the upstream hole. However, the shape of the nozzle hole 2b is not limited to this shape, and may be other shapes.

Since the downstream seat portion 1b of the valve body 1 collides with the conical surface or the spherical surface 2e of the downstream valve seat member 2, the material has high hardness, good weldability, and good mechanical properties (for example, heat treated material of SUS420J2). Make with.

In order to prevent fuel from leaking to the internal combustion engine, the valve body 1 is divided into an upstream portion and a downstream portion of the valve body 1, and each portion has a substantially spherical shape that is convex outward. A seat part is provided. The spherical sheet portion provided in the upstream portion of the valve body 1 is the upstream seat portion 1a, and the spherical sheet portion provided in the downstream portion of the valve body 1 is the downstream seat portion 1b.

In the present embodiment, since the fitting convex portion 1e with the valve body intermediate member 1c is provided at the upstream end portion of the valve body 1, the upstream seat portion 1a is slightly smaller than the upstream end portion of the valve body 1. It is provided at a position close to the downstream side (tip side). Since the collision force of the valve body 1 is applied to the upstream side seat portion 1a, the R portion is formed at the connecting portion 1d with the portion having a thin outer diameter such as the fitting convex portion 1e, and the stress due to the impact is relieved. It is good to. On the other hand, the downstream seat portion 1 b is provided at the downstream end of the valve body 1. The detailed operation of the valve body 1 will be described with reference to FIG.

As shown in FIG. 2, the valve body 1 has one or more sliding portions 18 with the inner surface of the nozzle body 3. The sliding portion 18 may be partially cut out of a cylindrical shape to form a flow path. Since the downstream seat portion 1b of the valve body 1 collides with the tapered surface of the downstream valve seat member 2, the downstream seat portion 1b is made of a material having high hardness, good weldability, and good mechanical properties (for example, a heat treatment material of SUS420J2).

The nozzle body 3 encloses the valve body 1, and guides the valve body 1 so as to be slidable in the direction along the central axis 100A on the inner peripheral surface thereof. In order to determine the spray phase, the nozzle body 3 has a shape (for example, a flat surface) necessary for alignment at the time of joining with the downstream valve seat member 2. One or more grooves 3a for attaching the seal member 19 are formed on the outer peripheral surface near the tip of the nozzle body 3 in order to seal the combustion gas generated in the internal combustion engine. In addition, the sliding part 18 of the valve body 1 can also cut out a part of surface which contacts and slides to the internal diameter of the nozzle body 3, and can also form the fuel flow path.

The nozzle body 3 is provided with a flange portion (expanded diameter portion) 3e that is expanded radially outward at an upstream end portion. A first urging member 4 and an annular adjustment ring 5 used for fine adjustment of the stroke amount are assembled to the flange portion 3e.

The first biasing member 4 is a component for biasing the valve body 1 in the upstream direction. The inner diameter of the first urging member 4 is set larger than the outer diameter of the valve body 1, and the outer diameter of the first urging member 4 is set smaller than the inner diameter of the first casing 7. The first urging member 4 is assembled coaxially with the nozzle body 3 and the valve body 1. One end surface of the first urging member 4 is seated on the upstream end surface (base end side) of the flange portion 3 e of the nozzle body 3. On the other hand, the other end surface of the first urging member 4 is seated on the lower surface (surface opposite to the upstream seat portion 1a) of the flange portion 1aa of the upstream seat portion 1a of the valve body 1. For this reason, the upstream seat portion 1 a has a diameter larger than the diameter of the central portion in the axial direction of the valve body 1. That is, the diameter of the valve body 1 is increased at a portion where the upstream seat portion 1a is provided, and the other end surface of the first biasing member 4 is seated on the lower end surface of the expanded diameter portion. The first urging member 4 polishes both end faces in order to prevent falling. The first biasing member 4 is made of a material such as SUS631 that is resistant to corrosion and has a large spring constant.

The details of the adjustment ring 5 are as follows. Since the dimensional variation occurs due to component tolerances of the valve body 1, the nozzle body 3, and the downstream valve seat member 2, it is necessary to adjust the dimensional variation of each component so that the required stroke amount (about 100 μm) can be obtained. . Therefore, the adjustment ring 5 that strictly manages the tolerance of the ring width W (see FIG. 1) adjusts the dimensional variations caused by the component tolerances of the valve body 1, the nozzle body 3, and the downstream valve seat member 2. As shown in FIG. 1, the adjustment ring 5 is fixed by abutting one end face on the flange portion 3 e of the nozzle body 3 and the other end face against the first casing 7. The adjustment ring 5 determines the difference between the actual dimension of the gap formed between the downstream seat portion 1b of the valve body 1 and the downstream valve seat 2c of the downstream valve seat member 2 and the required stroke amount. Adjust the plate thickness W to obtain the required stroke amount.

The first casing 7 is a component that encloses the first urging member 4 and performs fuel sealing when the engine is stopped in cooperation with the upstream seat portion 1a. The first casing 7 has an upstream valve seat 7a that comes into contact with the upstream seat portion 1a. When the first casing 7 is assembled to the nozzle body 3, the upstream seat portion 1 a of the valve body 1 is applied to the upstream valve seat 7 a of the first casing 7 by the force of the first biasing member 4 assembled earlier. It comes into contact. The upstream fuel passage is closed when the upstream seat portion 1a contacts the upstream valve seat 7a, and the upstream fuel passage is opened when the upstream seat portion 1a is separated from the upstream valve seat 7a.

As shown in FIG. 4, the first casing 7 has a structure for supporting the bellows body 8 on the upstream side. For example, a support portion 7b is provided between the first casing 7 and the upper metal fitting 8b of the bellows body 8 so that the bellows body 8 is supported. The support part may be integrated with the first casing 7 or may be separate. In this embodiment, a configuration in which the support portion 7b is integrated with the first casing 7 will be described.

A notch (opening) 7c is provided in the lower part of the support part 7b of the first casing 7 as a flow path of the fuel flow FF.

A valve body intermediate member 1c having a lower end portion fitted to the fitting convex portion 1e is connected to the upper end portion of the valve body 1. The valve body intermediate member 1 c is a relay member that relays between the valve body 1 and the drive element 11. In order to join the lower end portion of the bellows body 8 and the enlarged diameter portion 1cb of the valve body intermediate member 1c by laser welding, the first casing 7 is a through portion for passing a beam (notch portion 7c in this embodiment). Is provided. Since a high fuel pressure is applied to the first casing 7, the first casing 7 is made of a material having a large allowable yield strength and excellent weldability (for example, a precipitation hardening stainless steel such as SUS630).

4 is a part for welding the nozzle body 3 and the first casing 7. The welding ring 6 is temporarily fixed to the nozzle body 3 and the first casing 7 by press fitting, and then completely fixed by welding.

¡Because fuel pressure is applied to this location, it is necessary to secure a weld length of 0.5 mm or more. Since a high fuel pressure is applied to the weld ring 6, the weld ring 6 is made of a material having a large allowable yield strength and excellent weldability (for example, a precipitation hardening stainless steel such as SUS630).

The bellows body 8 is a component that shuts off the housing chamber of the drive element 11 and the fuel flow path so that fuel does not flow into the drive element 11 side. The bellows body 8 includes a bellows-like member (bellows member) 8a and an upper metal fitting 8b. The upstream end portion of the bellows-like member 8a is joined to the upper metal fitting 8b by welding, and the downstream end portion of the bellows-like member 8a is welded to the outer peripheral surface of the enlarged diameter portion 1cb formed at the lower portion of the valve body intermediate member 1c. It is joined by.

The upper metal fitting 8b is hollow with a through hole 8ba formed in the center. The cavity 8ba is a through hole that allows the space inside the bellows-shaped member 8a to communicate with the accommodation chamber of the drive element 11 when the bellows-shaped member 8a is welded to the upper metal fitting 8b. The valve body intermediate member 1c penetrates the inside of the bellows-like member 8a, protrudes from the upper end surface of the upper metal fitting 8b, and is joined to the drive element 11 by line contact. That is, the bellows-like member 8a is provided radially outward of the valve body intermediate member 1c and encloses the valve body intermediate member 1c. The bellows-like member 8a is assembled to the fuel injection valve 100 in a compressed state from an initial state that is a natural length (length in a natural state).

In this embodiment, the driving element 11 has a conical recess 11a on the lower end surface. Moreover, the valve body intermediate member 1c is formed in a substantially spherical shape at the upper end. The substantially spherical upper end portion of the valve body intermediate member 1c comes into contact with the opening edge of the recess 11a, so that the valve body intermediate member 1c is joined to the drive element 11 by line contact. The durability of the bellows body 8 is increased by keeping the bellows body 8 in a compressed state in the initial stage. Therefore, in order to compress the bellows body 8, a clearance 8d (see FIG. 10) is provided in the abutting portion of the first casing 7. Details of the initial compression of the bellows body 8 will be described later with reference to FIG.

In addition, as shown in FIG. 4, the bellows ring 15 is provided in the outer peripheral part by the side of the lower surface of the upper metal fitting 8b as components for adjusting the compression amount of the bellows-like member 8a. The dimensions of the bellows body 8 vary greatly depending on the bellows manufacturing method and joining, and the required amount of compression of the bellows-like member 8a varies. Therefore, a mechanism that can adjust the amount of compression of the bellows-like member 8a by adjusting the thickness of the bellows ring 15 is provided.

The second casing 9 is a component constituting a circular pipe member (cylindrical member) inside the casing body 16 having a double circular pipe structure, and the position in the circumferential direction of the drive element 11 and the compression amount of the bellows body 8 are determined. It is a component that holds and constitutes the fuel flow path. The upper metal fitting 8b of the bellows body 8 is pushed downward by a convex portion 9b protruding radially inward provided on the inner peripheral surface of the downstream end portion of the second casing 9, and the bellows body 8 is compressed. In this state, the outer periphery of the upper metal fitting 8b of the bellows body 8 and the outer periphery of the second casing 9 are joined by overlap welding. As shown in FIG. 5, there is a flange-like protrusion (annular protrusion) 9a protruding outward in the radial direction on the outer peripheral surface of the upstream end portion of the second casing 9, and the upper casing 13 is formed by the flange-like protrusion 9a. Align with.

Since the high fuel pressure is applied to the second casing 9, the second casing 9 is made of a material having a large allowable yield strength and excellent weldability (for example, a precipitation hardening stainless steel such as SUS630).

The upper casing 13 is a part that holds the damper body 12 and the fixing member 14 that fixes the damper body 12 on the inner peripheral surface side, and constitutes a fuel supply port 13a. Further, it is a mounting part for assembling the fuel injection valve 100 to the internal combustion engine.

In the upper casing 13, mounting holes for the second casing 9, the third casing 10, the damper body 12, and the fixed component 14 are formed coaxially to form a stepped hole 12 e. The fuel supply port 13 a is not configured coaxially with the hole for attaching the second casing 9 and the third casing 10. The third casing 10 is a part constituting a circular pipe member (cylindrical member) outside the casing body 16 having a double circular pipe structure, and is a part for constituting a fuel flow path together with the second casing 9. is there.

As shown in FIG. 5, the second casing 9 and the third casing 10 are inserted into the mounting hole 12 e from the downstream end face of the upper casing 13. The second casing 9 is provided with a flange-like projection 9a, and the third casing 10 is provided with a flange-like projection 10a. The positions of the flange-like protrusions 9a and the flange-like protrusions 10a are fixed in a state where the flange-like protrusions 9a and the flange-like protrusions 10a are in contact with the mounting holes 12e of the upper casing 13, respectively. Fixing and welding are performed in the order of the second casing 9 and the third casing 10.

Since the upper casing 13 is applied with a high fuel pressure, the upper casing 13 is made of a material having a large allowable yield strength and excellent weldability (for example, a precipitation hardening stainless steel such as SUS630).

The driving element 11 is a component for moving the valve body 1 in the direction in which the downstream seat portion 1b contacts the downstream valve seat 2c. As described above, the downstream end surface (lower end surface) 11a of the drive element 11 is in contact with the valve body intermediate member 1c. The downstream end surface 11a of the drive element 11 has a conical recess, and, like the downstream end surface 11a, reduces the surface pressure of the contact portion and prevents wear. The upstream end surface also includes the conical recess 11b, but another member including the conical recess can be assembled to the upstream end surface. When a voltage is applied to the driving element 11, the entire length is extended. In the case of a piezoelectric element which is an example of the driving element 11, it is configured by laminating thin ceramic elements, and when a voltage is applied, the entire length is extended from several μm to several tens of μm. Both ends of the element are fixed with a metal lid, and the outer periphery of the element is covered with a metal casing that can be expanded and contracted. A piezoelectric element made of ceramics has a very low linear expansion coefficient compared to metal, and is about 1/10 that of stainless steel.

The upstream end face of the third casing 10 is a flange-like protrusion 10a. The inner diameter from the downstream end face of the third casing 10 to the upstream side by about 10 mm is the same as the outer diameter of the first casing 7, but is 1 mm or more larger than the outer diameter of the first casing 7 on the upstream side. The third casing 10 is assembled to the upper casing 13 such that the nozzle body 3 is inserted into the inner periphery of the third casing 10 from the downstream end. The flange-like protrusion 10a of the third casing 10 is fixed by abutting against the mounting hole 12e of the upper casing 13, and the upper casing 13 and the outer periphery of the flange-like protrusion 10a of the third casing 10 are welded.

Further, the downstream inner diameter portion of the third casing 10 and the upstream outer diameter portion of the first casing 7 are press-fitted, and the downstream side of the third casing 10 and the upstream side of the first casing 7 are overlapped. The whole circumference is joined by welding. Thereby, a gap is formed between the outer diameter (outer circumference) of the second casing 9 and the inner diameter (inner circumference) of the third casing 10, and the fuel flows there.

The damper body 12 is a component for offsetting the difference in linear expansion coefficient between components. The damper body 12 is located on the upstream side of the drive element 11. The damper body 12 includes a protruding portion 12 c that is substantially spherical (hemispherical) at the end on the front end side, and abuts against a conical recess 11 b provided on the upstream end surface of the drive element 11. .

The damper body 12 includes a cylinder 12b, a plunger 12a, and a diaphragm 12d, and oil is sealed between the cylinder 12b, the plunger 12a, and the diaphragm 12d. The oil is injected between the cylinder 12b, the plunger 12a, and the diaphragm 12d in a deaerated state so that bubbles are not mixed. When the temperature rises, the oil expands, and the diaphragm 12d is deformed by the amount of the expansion, and the cylinder 12b connected thereto moves following it. This movement maintains contact so that a gap between the downstream valve seat 2 and the valve body 1 does not occur. The damper body 12 has a characteristic that does not vary in the behavior when the driving element 11 is driven at a high frequency.

The fixing part 14 is a part for fixing the damper body 12. The driving force of the driving element 11 in contact with the damper body 12 is 1000 N or more, and the press-fitting load applied to the fixed component 14 is set so that the fixed component 14 does not move in the axial direction even if this load is received. .

The fixing method of the fixing part 14 is as follows. The fixed component 14 is press-fitted into the inner peripheral surface 13 b of the upper casing 13. Fine adjustment is performed so that the press-fitting length of the fixed component 14 becomes a specified value. When the movement amount of the valve body 11 reaches a specified value, the upper casing 13 and the fixed component 14 are temporarily fixed. The fixing method is caulking. Thereafter, the upper casing 13 and the fixing component 14 are joined and completely fixed so as to withstand the load when the driving element 11 is driven.

FIG. 6 is an enlarged cross-sectional view showing the state of the upstream sheet portion 1a under each condition. FIG. 7 is an enlarged cross-sectional view showing the state of the downstream sheet portion 1b under each condition. FIG. 8A is a diagram showing the relationship between the applied voltage of the fuel injection valve 100 according to the present invention and the contact state between the valve seats of the upstream seat portion 1a and the downstream seat portion 1b. FIG. 8B is a diagram showing a contact state of the upstream seat portion 1a and the downstream seat portion 1b shown in FIG. 8A with the valve seats. FIG. 8B shows the contact state of the upstream seat portion 1a and the downstream seat portion 1b with the valve seats corresponding to the steps (1) to (6) shown in FIG. 8A.

The fuel pressurized to the specified pressure by the pressurizer is supplied to the fuel supply port 13a provided in the upper casing 13 via a fuel pipe (not shown) and flows into the fuel injection valve 100.

(1) in FIG. 8A and FIG. 8B shows a state when the engine and the fuel pressurizing device are stopped. At this time, no voltage is applied to the drive element 11. In this state, the valve body 1 is pushed up to a position where the upstream seat portion 1a contacts the upstream valve seat 7a by the force of the first biasing member 4 provided on the valve body 1, and the upstream seat portion 1a The fuel passage between the upstream valve seat 7a is closed (the state shown in FIG. 6A). In this case, since the fuel pressurizing device is stopped, fuel is not supplied. However, the fuel supplied until the previous operation of the engine is stopped by the upstream seat portion 1a and the upstream valve seat 7a. It is stopped and does not flow down to the downstream side of the upstream seat portion 1a and the upstream valve seat 7a. Therefore, the fuel injection valve 100 is in a closed state. The fuel passage between the downstream seat portion 1b and the downstream valve seat 2c is in an open state (the state shown in FIG. 7A).

8A and 8B (1), the fuel is supplied when the fuel pressurizer is operated while the engine is stopped. However, in this state, no voltage is applied to the drive element 11. Therefore, the valve body 1 is pushed up in the upstream direction by both the urging force of the first urging member 4 and the upstream force acting from the bellows body 8. As a result, the upstream seat portion 1a of the valve body 1 contacts the upstream valve seat 7a of the first casing 7, and the state where the fuel passage between the upstream seat portion 1a and the upstream valve seat 7a is closed is maintained. (The state of FIG. 6A). In this state, although the fuel passage on the downstream seat portion 1b side is open, the fuel passage on the upstream seat portion 1a is closed, so that the fuel flow is blocked. Also in this case, the fuel injection valve 100 maintains the closed state. If the fuel is not shut off at this time, the fuel flows into the combustion chamber of the internal combustion engine, and compression may occur when the engine is started, which may destroy the internal combustion engine.

(2) in FIG. 8A and FIG. 8B shows a state in which the engine is started after the fuel pressurizing device is started (a state in which the engine is operating). In this state, fuel is injected from the fuel injection valve 100 by a predetermined flow rate based on a command value from the engine control unit. The valve body 1 has a ratio of the flow area on the downstream seat portion 1b side to the flow area on the upstream seat portion 1a side so that the required flow of fuel flows and pressure loss and spray performance are maintained. So that the voltage applied to the drive element 11 is controlled. That is, the drive voltage of the drive element 11 is controlled to the intermediate voltage of FIG. 8A, the fuel passage between the upstream seat portion 1a and the upstream valve seat 7a is opened (state of FIG. 6B), and the downstream seat The fuel passage between the portion 1b and the downstream valve seat 2c is also opened, and the fuel injection valve 100 is opened (state shown in FIG. 7A).

(3) in FIG. 8A and FIG. 8B shows a state in which fuel injection is stopped in a state where both the engine and the fuel pressurizing apparatus are operating. The drive element 11 is energized so that the downstream seat portion 1b of the valve body 1 and the downstream valve seat 2c come into contact with each other. Thereby, the valve body 1 moves to the downstream valve seat 2c side. As a result, the fuel flow path is closed and fuel injection stops. That is, the fuel passage between the upstream seat portion 1a and the upstream valve seat 7a is open (the state shown in FIG. 6C), but between the downstream seat portion 1b and the downstream valve seat 2c. The fuel passage is closed (the state shown in FIG. 7C), and the fuel injection valve 100 is closed.

When the engine is driven, the state (2) and the state (3) in FIGS. 8A and 8B are repeated to supply the fuel amount required for combustion of the engine from the fuel injection valve 100 at an appropriate timing. Is possible. The state of (4) in FIGS. 8A and 8B is the same state as (3), and the state of (5) is the same state as (2). However, in the state of (5), the engine and the fuel pressurizing device are stopped halfway, and the valve body 1 is caused by both the urging force of the first urging member 4 and the upstream force acting from the bellows body 8, It is pushed up upstream. Thereby, the upstream seat part 1a contacts the upstream valve seat 7a, and the fuel injection valve 100 stops its operation in the closed state.

That is, in the fuel injection valve 100 of the present embodiment, the upstream side seat portion 1a is separated from the upstream side valve seat 7a, and the downstream side seat portion 1b is separated from the downstream side valve seat 2c. To inject fuel. The fuel injection valve 100 is a first urging member 4 that urges the valve body 1 in a direction in which the upstream seat portion 1a contacts the upstream valve seat 7a when the drive element 11 is not energized. The upstream biasing force including the biasing force is configured to be larger than the downstream biasing force that biases the valve body 1 in the direction in which the downstream seat portion 1b contacts the downstream valve seat 2c. The fuel injection valve 100 drives the drive element 11 so that the downstream biasing force including the driving force of the drive element 11 is larger than the upstream biasing force during energization of the drive element 11, whereby the downstream seat The portion 1b is brought into contact with the downstream valve seat 2c to close the downstream fuel passage.

FIG. 9 is a diagram showing a force relationship acting on the valve body 1 of the fuel injection valve 100 according to the present invention.

Fig. 9 (1) shows the force acting when the engine and the fuel pressurizer are stopped. The load (force) relationship of each part is as shown in (Equation 1).

The k ₁ x ₁ compression amount x ₁ and a spring constant k ₁ of the first biasing member 4, a force which the valve body 1 is biased to the upstream direction. F ₁ is a load by which the damper body 12 pushes the drive element 11 in the downstream direction.

FIG. 9 (2) shows the force that acts when the fuel pressure is applied by operating the fuel pressurizing device with the engine stopped. The load (force) relationship of each part is as shown in (Equation 2).

The k ₁ x ₁ compression amount x ₁ and a spring constant k ₁ of the first biasing member 4, a force that is biased to the upstream direction. (ΠD ₃ ^2/4) P is the fuel pressure P acts on the effective diameter D ₃ of the bellows member 8, a force that the valve body 1 is biased to the upstream direction. This is because the inside of the bellows body 8 becomes an air layer, and pressurized fuel exists outside. (ΠD _{² 2/4)} P is the pressure P of the liquid acts on the seat diameter D _2, a force is biased in a downstream direction. F ₁ is a load by which the damper body 12 pushes the drive element 11.

Fig. 9 (3) shows the force acting during fuel injection. The load (force) relationship of each part is as shown in (Equation 2).

k ₁ x ₁ by compression amount x ₁ and a spring constant k ₁ of the first biasing member 4, a force that is biased to the upstream side direction. (ΠD ₃ ^2/4) P is fluid pressure P acts on the effective diameter D ₃ of the bellows member 8, a force that the valve body 1 is applied to the upstream side direction. This is because the inside of the bellows body 8 becomes an air layer, and pressurized fuel exists outside. F ₁ is a force applied to the downstream side pushing the damper body 12. F ₂ is a force by which the valve element 1 is pushed downstream by the drive element 11. The right term and the left term are balanced in an equilibrium state, and the valve body 1 stops at a desired position.

Fig. 9 (4) shows the force acting when fuel injection is stopped. The load (force) relationship of each part is as shown in (Equation 4).

(ΠD ₁ ^2/4) P is fluid pressure P acts on the downstream side seat diameter D ₁ of the valve body 1, a force applied to the upstream side direction. k ₁ x ₁ by compression amount x ₁ and a spring constant k ₁ of the first biasing member 4, a force which the valve body 1 is biased to the upstream side direction. (ΠD ₃ ^2/4) P is fluid pressure P acts on the effective diameter D ₃ of the bellows member 8, a force that the valve body 1 is biased to the upstream side direction. This is because the inside of the bellows body 8 becomes an air layer, and pressurized fuel exists outside. F ₁ is a force by which the damper 12 pushes the drive element 11 and is a force toward the downstream side. F ₂ is a force by which the valve element 1 is pushed downstream by the drive element 11.

If the above force relationships (1) to (4) are not established, fuel does not inject, and the valve body 1 does not come into contact with the downstream valve seat 2c, causing problems such as fuel leaking.

FIG. 10 is a diagram showing details of the method for assembling the bellows body 8 of the fuel injection valve 100 according to the present invention.

In the bellows body 8, when the second casing 9 is assembled, the upper metal fitting 8b of the bellows body 8 is dragged by the second casing 9, and the bellows-like member 8a is compressed. When the amount of compression of the bellows-like member 8a exceeds the allowable compression value, the bellows-like member 8a undergoes plastic deformation, loses its elasticity, and the valve body 1 does not move. Therefore, it is necessary to provide a receiving part on the lower end surface of the upper metal fitting 8b or to provide a receiving part on the first casing 7 to suppress the compression amount of the bellows-like member 8a.

On the other hand, the bellows body 8 is stretched due to fluid pressure, temperature, and movement of the valve body 1. At this time, if the amount of elongation of the bellows-like member 8a exceeds the allowable elongation value, the bellows-like member 8a undergoes plastic deformation, loses its elasticity, and the valve body 1 does not move. Although improvement can be achieved by changing the material of the bellows-like member 8a, increasing the pressure of the bellows, and increasing the overall length, the improvement of the bellows body 8 is restricted by the allowable dimensions of the fuel injection valve 100 and the internal combustion engine layout of the counterpart side. Therefore, as shown in FIG. 10, the bellows-like member 8a is compressed during assembly to increase the amount of elongation. Therefore, as a structure having a gap 8d between the first casing 7 and the lower end surface of the upper metal fitting 8b of the bellows body 8, the upper metal fitting 8b is sandwiched between the second casing 9 and the first casing 7, and the bellows-like member 8a The structure to which compression is applied. The bellows ring 15 is a component for absorbing dimensional variations of the bellows body 8.

FIG. 11 is a detailed sectional view of the valve body 1 and the nozzle body 3 of the fuel injection valve 100 according to the present invention.

Supplied fuel is gradually subject to loss (pressure drop) due to shear resistance generated inside the channel from the upstream. Therefore, the amount of fuel ejected from the nozzle hole 2b of the valve seat 2 is smaller than that supplied from the upstream portion. In particular, since the flow path 17 formed by the valve body 1 and the nozzle body 3 is narrow and long, loss tends to occur. Therefore, the inner diameter of the nozzle body 3 is gradually increased toward the upstream portion so that the flow resistance can be reduced and the pressure loss can be reduced. That is, the nozzle diameters d1, d2, and d3 of the nozzle body 3 are configured to satisfy the relationship of d1 <d2 <d3 as it goes upstream from the downstream portion.

According to the present embodiment, the valve element intermediate member 1c fixed to the valve element 1 is provided, and the expansion and contraction of the drive element (piezoelectric element) 11 is transmitted to the valve element 1 via the valve element intermediate member 1c. A mechanism in which the body 1b is pulled up from the valve seat 2c can be realized. For this reason, the fuel injection valve 100 which injects a fuel from the injection hole 2b with a simple mechanism is realizable. In the fuel injection valve 100, the fuel pressure acting on the valve body 1 and the force relationship of the urging member 4 can be appropriately set, the contact between the valve seat 2c and the valve body 1 can be made good, and the oil tight performance can be improved. It can be maintained well.
[Example 2]
FIG. 12 shows an overall view of the fuel injection valve according to the present embodiment. FIG. 12 (a) shows the fuel injection valve 1 in the closed state, and FIG. 12 (b) shows the fuel injection valve. The enlarged view when it is in a valve open state is shown.

Fuel is supplied from a fuel supply port 208 above the fuel injection valve. The fuel flows through the gap in the double circular pipe and reaches the valve seat through the gap between the nozzle 203 and the valve body 202. The driving element 206 uses an element that expands in proportion to voltage or current. Further, a valve element drive mechanism 212 is provided at the lower end of the drive element 206, and has a function of converting the operation of the drive element 206 extending in the downstream direction into the upstream direction. As will be described later, according to the present embodiment, the valve body drive mechanism 212 and the end of the valve body 202 are in contact with each other, and the valve body 202 can be lifted upstream. The valve seat 201 is formed on the outer peripheral portion of the tip of the nozzle 203, and the valve seat 201 is provided at the tip of the nozzle 203. The valve seat 201 is joined to the tip of the nozzle 203 by welding or the like. When the driving element 206 is operated, the valve body 202 that is in contact with the valve element 202 is pushed downward, the valve body 202 is separated from the valve seat 201, the seat portion fuel flow path 210a is formed, and the valve seat 201 is opened. Fuel is injected from the nozzle hole 211. When the energization is completed, the valve body 202 and the valve seat 201 come into contact with each other by the force of the spring 204 provided in the valve body 202, and a gap generated thereby closes the seat portion fuel flow path 210 and the injection is finished.

As described in the background, a fuel injection valve having a drive element 206 and a piezoelectric element 217 (piezo element) generally has a structure in which fuel is injected by pushing a valve body 202.
Therefore, from the viewpoint of strength and the like, the tip of the valve body generally takes a conical shape, and the generated spray is an umbrella spray. Compared to a flow control valve that is capable of pulling up the valve body 202 by energization that is currently being developed and allowing the fuel to be ejected from a plurality of injection holes, there is a problem that the degree of freedom of the spray layout is small.

Therefore, in this embodiment, by providing the valve body drive mechanism 212 between the drive element 206 and the valve body 202, the valve body 202 can be lifted up while using the drive element 206. As shown in FIGS. 12A and 12B, the valve is opened when energized, and the valve is closed when de-energized. As a result, it is possible to obtain an effect that a plurality of fuel injection holes can be used. The structure and operating principle of the valve body drive mechanism will be described in detail later.

FIG. 13 shows an enlarged cross-sectional view of the valve body drive mechanism 212. In addition, FIG. 14 shows a three-dimensional view of the valve body drive mechanism 212. The valve body drive mechanism 212 includes a rod 213, a drive element 206, a plate-like member 214a, a ring-like member 214, a pedestal portion 215, a valve body cap portion 216, and a metal seal portion B 205b. Next, these operation mechanisms will be described. Further, in the case of a flow control valve using the drive element 206, deterioration or corrosion occurs when the drive element 206 comes into contact with the fuel, so a metal seal member is installed.

In the present embodiment, the ring-like member 214 or the plate-like member 214a is called a push-up portion because it plays the role of pushing up the valve body 202. Further, the valve body drive mechanism 212 includes a support portion (a pedestal portion 215) that contacts and supports the push-up portion (ring-shaped member 214, plate-shaped member 214a) on the outer peripheral side of the inner peripheral side end. The rod 213 has a push-up portion (ring-like member 214, plate-like member 214a) and a contact portion 221 between the support portion (pedestal portion 215) and the push-up portion (ring-like member 214, plate-like member 214a) on the outer peripheral side. In contact, the push-up portion (ring-shaped member 214, plate-shaped member 214a) is moved downward. Therefore, in this embodiment, the rod 213 is referred to as an operation unit.
The push-up portion (ring-shaped member 214, plate-shaped member 214a) moved downward by the operating portion (rod 213) pushes up the valve body 202 by contacting the valve body 202 on the inner peripheral side with respect to the contact portion 221.

Contrary to the structure of the present embodiment, the operating portion (rod 213) includes a push-up portion (ring-like member 214, plate-like member 214a), a support portion (pedestal portion 215) and a push-up portion (ring-like member 214). Further, the contact portion 221 with the plate-like member 214a) may be contacted on the inner peripheral side and moved downward.

13 and 14, the operation of the valve body drive mechanism 212 of the present embodiment will be specifically described. The plate-like member 214 can lift the valve body 202 upward by the lever principle. A driving element 206 is provided on the upper part of the valve body driving mechanism 212. When the driving element 206 is energized, the driving force is transmitted in the downstream direction. At this time, the support part (pedestal part 215), the action part (rod 213), and the push-up part (ring-like member 214, plate-like member 214a) of the plate-like member 214a are operated by the action of the fulcrum, the force point, and the action point. Thus, the driving force transmitted in the downstream direction can be converted into the force in the upstream direction.

Specifically, the push-up portion has a frame member (ring-shaped member 214) disposed at a position in contact with the operating portion (rod 213), and the driving force by the driving element 206 is applied to the frame member (ring-shaped member 214). The transmitting operation unit is configured by a plurality of rods 213 provided in the axial direction between the drive element 206 and the frame member (ring-shaped member 214). Further, the plurality of rods 213 are arranged with an equal interval in the circumferential direction. The plate-like member 214a is attached to the inner peripheral side of the ring-like member 214, and the plurality of rods 213 urge the ring-like member 214 to move the plate-like member in the downstream direction.

It is possible to provide a metal member that connects the frame member 223 and the plate-like member 214a (ring-like member 214) over the entire circumference instead of the plurality of rods 213. However, this embodiment can reduce the material. Become. Further, it is desirable that the plurality of rods 213 be arranged with at least three and equal intervals. This is because the force applied from the drive element 206 disposed on the valve body drive mechanism 212 is equally applied to the valve body drive mechanism 212. In addition, when they are not evenly arranged, the valve body drive mechanism 212 may be inclined. It is preferable to avoid tilting because it can cause failure and damage to parts.

According to the valve body drive mechanism 212 of the present embodiment, as described above, the plurality of rods 213 urge the ring-shaped member 214 and the plurality of plate-shaped members 214a, whereby the valve body 202 is upstream (or) a plurality of sheets. The plate-like member 214 is provided with an equal interval. Further, like the rod 213 described above, it is desirable that a plurality of plate-like members 214a, more specifically three or more, be arranged. This is also because there is a concern that the force of the drive element 206 transmitted from the upper part is biased and prevents the force from being transmitted to the downstream part. If the operation of transmitting the force from the drive element 206 to the downstream with inclination is repeated, This may cause failure and damage of the member 214. The plate-like member 214 is desirably a metal from the viewpoint of strength.

The valve body drive mechanism 212 has a flange portion at the top of the valve body 202, and the flange portion is in contact with the inner peripheral side end of the push-up portion (plate-like member 214a). In addition, a flange part points out the part which protrudes in the outer peripheral part of the cap part 216 of FIG. Further, the flange portion is formed on the cap portion 216 provided at the upper end portion of the valve body 202, but the present invention is not limited to this, and the flange portion may be formed on the upper portion of the valve body 202. When this portion catches the plate-like member 214 described above, the valve body plays a role of being pushed up in the upstream direction.

That is, in the flow rate control valve provided with the valve body driving mechanism 212 described above, the flange portion is provided at the upper portion of the valve body, and the valve body and the flange portion can be applied even when they are separate bodies. The valve body of the fuel injection valve using the drive element 206 is very long. Therefore, there is a problem that processing is difficult when the flange portion is installed on the upper portion of the valve body. Therefore, a fuel seal member B 205b separate from the valve body and a cap member 216 disposed on the metal seal member are provided on the upper part of the valve body. By taking this configuration, the processing is simplified. In fact, simplification of assembly when assembling the flow control valve can also be expected. Further, the fuel seal member bracket B 205b need not be a metal as long as it can play a role of sealing the fuel, and other materials can be used.

At this time, the valve body drive mechanism 212 can be applied to any flow control valve, but in the present embodiment, a fuel injection valve will be described as an example.

In the valve body driving mechanism 212 described above, the push-up portion (plate-like member 214a) is in contact with the lower portion of the flange portion, and when the portion that contacts the lower portion of the flange portion is the action point and the portion that the rod 213 is in contact is the force point, The valve body 2 is pushed up with the portion provided at the lower part of the (plate-like member 214a) as a fulcrum. Thus, the push-up portion (ring-shaped member 214, plate-shaped member 214a) can push up the valve body 2 by utilizing the principle of leverage. This operation will be described with reference to FIG. FIG. 15A shows a state before the drive element 6 is energized. Therefore, the plate-like member 214 described above also exists on a plane without being pushed down. Next, FIG. 15B shows the valve body drive mechanism 212 at the time when the energization to the drive element 206 is started. As can be seen from this figure, the driving force generated from the driving element 206 is transmitted to the plate-like member 214 through the operating portion. As a result, the outer peripheral side end of the plate-like member 214 is pushed down in the downstream direction. As a result, the contact portion 221 acts as a fulcrum and the push-down portion acts as an action point, and pushes up the valve body 202 in the upstream direction. FIG. 15 (3) shows a state where the plate-like member 214 is pushed down to the extent that it contacts the pedestal. As is clear from this figure, the valve body 202 is pushed up by pushing down the operating portion (rod 213). In summary, even when a driving force is shown in the downstream direction after the drive element 206 is energized, a force in the opposite direction to the driving force can be transmitted to the valve body 202 itself via the valve body driving mechanism 212. it can.

The fuel injection valve provided with the valve body drive mechanism 212 has a plurality of injection holes. In general, in a fuel injection valve that performs fuel injection using the drive element 206, the drive element 206 has a structure that expands when a voltage is applied. Therefore, a structure in which fuel is injected by pushing the valve body 202. It becomes.
Therefore, in order to solve the problem of strength, the tip of the valve body 202 is generally conical, and the generated spray is an umbrella spray. However, compared with a fuel injection valve that pulls up the valve body 202 by energization and sprays fuel from a plurality of injection holes, the degree of freedom of spray layout is very low. In order to efficiently spray the fuel injection valve, it is preferable to improve the spray layout even when the drive element 206 is used.

Therefore, in this embodiment, the driving direction of the driving element 206 is reversed using the valve body driving mechanism 212, so that fuel can be injected in the same manner as the fuel injection valve that drives the valve body 202 by energization. . Therefore, even the fuel injection valve of this embodiment in which fuel is injected by the drive element 206 can be provided with a plurality of injection holes. As a result, even when the drive element 6 is used, it is possible to obtain a specific effect that improvement in spray layout can be expected.
[Example 3]
In the second embodiment, an example in which the drive element 206 is used as a drive unit has been introduced. In this embodiment, a piezoelectric element 217 is used as the drive element 6 as shown in FIG. The piezoelectric element 217 has a significantly faster operation cycle than the other driving elements 206, and thus can be driven with a low injection pulse, and exhibits a remarkable effect that fuel can be stably injected with a small amount. .

However, when fuel is injected, the fuel injection valve itself is also in a high temperature state. In some cases, the linear expansion coefficient of a member constituting the piezoelectric element 217 is smaller than that of a metal part (for example, stainless steel) constituting the flow control valve. At this time, when the temperature rises, the metal constituting the flow control valve greatly expands, but the drive element 206 does not extend beyond the metal, and as a result, the distance to push down the valve body 202 is shortened, and the fuel is reduced. This causes a problem that the seal cannot be sealed and continues to flow out.

Therefore, in the fuel injection valve provided with the valve body drive mechanism 212 of this embodiment, a damper 207 is provided on the drive element 206. The damper 207 is composed of a cylinder and a plunger, and additionally oil sealed in a gap between the cylinder and the plunger. Since oil is sealed in the gap between the cylinder and the plunger, when the temperature rises, the oil expands and the cylinder extends. By extending the cylinder in this way, there is no gap between the valve seat and the valve body 202. For this reason, the elongation amount by the drive element 206 can be made larger than the elongation amount of the metal which comprises a fuel injection valve. In the case of the present embodiment, since the valve body driving mechanism 212 is provided, the interval until the driving force is applied to the valve body 202 becomes longer, and thus the extension amount by the driving element 206 is shortened to some extent. Therefore, the damper 7 plays an important role.

Note that the piezoelectric element 217 can be installed in a liquid if it has a waterproof and sealed structure or has fuel resistance.

In the second embodiment and the third embodiment described above, “a push-up portion that pushes up the valve body, a support portion that contacts and supports the push-up portion on an outer peripheral side of an inner peripheral side end portion of the push-up portion, and the support portion And an operation part that moves the push-up part downward in contact with the push-up part on the outer peripheral side of the contact part between the push-up part and the push-up part. It has a configuration in which the valve body is pushed up by contacting the valve body on the inner peripheral side of the contact portion. Accordingly, the valve body that contacts the valve body on the outer peripheral portion of the nozzle tip, and the valve body that operates so as to close the fuel passage by contacting the valve seat and to form the fuel passage by moving away from the valve seat. It is possible to provide a flow control valve that can be ejected from the multi-holes with a simple mechanism.
[Example 4]
In the embodiment described above, the inner opening valve structure has been described. However, by applying a part of the valve body driving mechanism to the outer opening valve structure, the valve body driving mechanism can be realized with a simple structure. it can. Hereinafter, description will be given with reference to the drawings.

FIG. 17 is a diagram illustrating the flow control valve according to the present embodiment. This is a control valve that is normally closed (when no voltage is applied) to the tip of the valve body 302. Fuel is supplied from a fuel supply port 308 above the flow rate control valve, flows through the gap in the double circular pipe, and reaches the valve seat from the gap between the nozzle 303 and the valve body 302. The drive element 306 is an element that expands in proportion to voltage or current.
The drive element may be a solenoid such as a coil in which a wire is wound on the circumference. In this case, when the coil is energized, the valve body 2 is pushed down by the magnetic attractive force.

The tip of the valve element 302 is in contact with the lower end of the drive element 306 and is directly operated by the operation of the drive element 306. The valve seat 301 is formed on the outer periphery of the tip of the nozzle 303. A cap component 312 is provided at the tip of the nozzle 303. When the driving element 306 operates, the abutting valve body 302 is pushed downward, the valve body 302 is separated from the valve seat 301, the seat portion fuel flow path 310 is formed, and the cap part 312 is opened. The fuel is injected from the nozzle hole 311. When the energization is completed, the valve body 302 and the valve seat 301 come into contact with each other by the force of the spring 304 provided on the valve body 302, and the clearance generated thereby closes the seat portion fuel flow path 310 and the injection ends.

When a piezoelectric element is used for the drive element 306, some members constituting the piezoelectric element have a smaller linear expansion coefficient than metal parts (for example, stainless steel) constituting the flow control valve. At this time, when the temperature rises, the constituent metal greatly expands, but the piezoelectric element does not extend and the distance to push down the valve body 302 becomes relatively short, and the stroke amount of the valve body 302 decreases, and finally The valve will not open.

Therefore, a damper 307 is provided so that there is no gap between the valve body 301 and the piezoelectric element when the temperature rises. The damper 307 includes a cylinder and a plunger, and oil is sealed in a gap between the cylinder and the plunger. When the temperature rises, the oil expands and the cylinder extends. Due to this elongation, there is no gap between the valve body 302 and the piezoelectric element. Note that the piezoelectric element can be installed in a liquid if it has a waterproof and sealed structure or has fuel resistance. Since the operation cycle of the piezoelectric element is very fast, it can be driven with a low injection pulse and can be stably injected with a small flow rate.

FIG. 18 is a diagram showing details of the first to third reference examples. Both ends of the metal seal member 305a are press-fitted into the metal seal member upstream metal fitting 305b and the metal seal member downstream metal fitting 305c, and the press-fitting portions are joined by welding or the like. Since fuel pressure is applied to this location, it is necessary to ensure airtightness that is higher than the assumed fuel pressure.

After the metal seal member 305a is joined to the metal seal member upstream metal fitting 305b and the metal seal member downstream metal fitting 305c, the metal seal member downstream metal fitting 305c has the end surface of the valve body 302 at the tip end surface of the metal seal member. It press-fits into the downstream metal fitting press-fitting part 305d and is fixed by outer periphery welding or the like of the metal fitting press-fitting part. The metal seal member upstream metal fitting 305b is press-fitted into the valve body 302 with the metal seal member downstream metal fitting 305c, pressed into the inner pipe part 311 and joined by welding or the like from the outer peripheral side of the inner pipe part 311. .

One side of the metal seal member downstream metal fitting 305c has a shape on a bar, and the tip is a spherical surface. This is attached so as to penetrate the inside of the metal seal member 305a. This spherical surface is configured to come into contact with the end face of the drive element 306. The overall length of the cylinder is determined so that the spherical surface always protrudes from the metal seal member 305a in the assembled state. A conical groove is formed on the end face on the front end side of the drive element 306, and the front end spherical surface of the metal seal member downstream side metal fitting 305c enters into and comes into contact with the groove. Thereby, the surface pressure of a contact surface can be reduced. In addition, when both material hardness is high, not a conical groove | channel but a flat surface may be sufficient.

The metal seal member downstream metal fitting 305 c transmits the movement of the drive element 6 to the valve body 2. At this time, since the metallic seal member upstream metal fitting 305b is fixed to the inner pipe part 311, the metallic seal member 305a has a stretchable structure. The shape is bellows, and the bellows part expands and contracts to follow the movement of the metal seal member downstream metal fitting 305c. In addition, as long as the material itself satisfies the stretchability and the required strength, a cylindrical member other than the bellows shape may be used.

Since the distance from the sliding portion 313 of the valve body 302 can be taken, deformation of the sliding portion can be suppressed, and the amount of leakage from the distal end portion of the valve body 302 and variation in spraying can be reduced. is there.

As described above, in the present embodiment, the valve seat that contacts the valve body 2 is provided at the inner peripheral portion of the tip of the nozzle 303, and the fuel passage is closed by the valve body 302 contacting the valve seat of the nozzle 303. Operate to form a fuel passage by leaving. A drive element 306 that drives the valve element 302 and a seal member 305 that shields the fuel flow path are provided on the lower surface of the drive element 306 and on the upper part of the valve element 302. More specifically, the seal member is made of metal, is disposed immediately below the drive element 306, and is attached to the upper end portion of the valve body 302.

The seal mechanism 305 includes a metal seal member 305a that seals the fuel flow path around the valve body 302 and the drive element 306 side. A metal seal member downstream metal fitting 305c attached to the valve body 302 is disposed on the inner peripheral side of the metal seal member 305a, and a lower surface of the metal seal member downstream metal fitting 305c and an upper surface of the metal seal member 305a are arranged. By contacting, the fuel flow path around the valve body 302 and the drive element 306 side are sealed.

The upper end of the metal seal member downstream metal fitting 305c is in contact with the lower surface of the drive element 306, and when the drive element 306 is driven, this driving force is transmitted via the metal seal member downstream metal fitting 305c and the metal seal member 305a. It is transmitted to the valve body 302. A metal seal member upstream metal fitting 305b is disposed between the metal seal member 305a and the drive element 306, and the metal seal member downstream metal fitting 305c passes through the inner peripheral side of the metal seal member upstream metal fitting 305b. Contact the driving element 306. At this time, it is desirable that a conical recess is formed on the lower surface of the drive element 306, and the upper end of the metal seal member downstream metal fitting 305c is in contact with the recess.

Further, the metal seal member 305a has a bellows mechanism that can be expanded and contracted with the valve body 302. When the drive element 306 is driven, the metal seal member downstream metal fitting 305c is energized, and at this time, the metal seal member By extending the bellows mechanism 305 a, the extension of the drive element 306 is transmitted to the valve body 302. The metal seal member 305a and the metal seal member downstream metal fitting 305c are fixed by welding, and the metal seal member downstream metal fitting 305c is fixed over the valve body 302.

Metal fittings that can be attached to the constituent members of the valve body 302 are joined by welding or the like to both sides of a metal seal member downstream metal fitting 305c that shields the fuel flow path.

In a structure in which the fuel shielding member is joined directly to the valve body by welding or the like, the valve body may be deformed by the influence of welding or the like, and may slide with the nozzle portion. Further, the structure in which the fuel shielding member is arranged in the nozzle portion has a problem that the outer diameter of the nozzle is enlarged. In this embodiment, in a flow control valve provided with a valve body that moves in the axial direction and a drive element that drives the valve body, a seal member that shields the drive element and the fuel passage is provided on the lower surface of the drive element, and It is provided at the top of the body. As a result, the accuracy of the flow control valve can be improved, and the degree of freedom of attachment to an internal combustion engine or the like can be improved.

In addition, this invention is not limited to each above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

In the present embodiment, the fuel control valve using the drive element has been mainly described. However, the present invention may be applied to a magnetostrictive element or a piezoelectric element among the drive elements, or may be applied to a flow control valve other than the fuel control valve. You may apply. Also, the method of arranging the fuel injection valve is not limited to the example in the above embodiment.

DESCRIPTION OF SYMBOLS 1 ... Valve body, 1a ... Upstream part seat part, 1b ... Downstream part seat part, 1c ... Valve body intermediate member, 2 ... Downstream valve seat, 2a ... Downstream seat part, 2b ... Injection hole, 3 ... Nozzle body, DESCRIPTION OF SYMBOLS 4 ... 1st biasing member, 5 ... Adjustment ring, 6 ... Welding ring, 7 ... 1st casing, 7a ... Upstream valve seat, 7b ... Supporting part, 8 ... Bellows body (seal body), 8a ... Bellows member, 8b ... Upper metal fitting, 8c ... Clearance, 9 ... Second casing, 9a ... Flange-like projection, 10 ... Third casing, 10a ... Flange-like projection, 11 ... Drive element, 11a ... Recessed portion on the downstream side of the drive element, 11b ... Recessed portion on the upstream side of the drive element, 12 ... damper body, 12a ... plunger, 12b ... cylinder, 12c ... projection, 12d ... diaphragm, 13 ... upper casing, 13a ... fuel supply port, 14 ... fixed part, 15 ... bellows ring 1 DESCRIPTION OF SYMBOLS ... Casing body, 17 ... Flow path, 18 ... Sliding part, 19 ... Seal member, 201 ... Valve seat, 202 ... Valve body, 203 ... Nozzle, 204 ... Spring, 205 ... Metal sealing member, 205a ... Metal seal Member bracket A, 205b ... Metal seal member bracket B, 206 ... Drive element, 207 ... Damper, 208 ... Fuel supply port, 209 ... Voltage input terminal, 210 ... Seat portion, 210a ... Seat portion fuel flow path, 211 ... Jet Hole 212, valve body drive mechanism, 213 rod, 214, frame member, 214a plate member, 215 base, 216 metal seal member upper metal cap, 217 piezoelectric element, 220 pusher, 221 support , 222 ... operation part, 301 ... valve seat, 302 ... valve body, 303 ... nozzle, 304 ... spring, 305 ... metallic seal part, 305a ... metal sealing member 305b ... Metal seal member upstream metal fitting, 305c ... Metal seal member downstream metal fitting, 305d ... Metal seal member downstream metal fitting press fitting portion, 306 ... Drive element, 306a ... Drive element end face groove portion, 307 ... Damper, 308 ... Fuel supply port, 309... Voltage input terminal, 310... Seat portion, 310 a... Seat portion fuel flow path, 311.

Claims (5)

1. A valve body configured to be displaceable in the axial direction and having an upstream seat portion disposed on the upstream side in the fuel flow direction in the axial direction and a downstream seat portion disposed on the downstream side;
   An upstream valve seat in which the upstream fuel passage is closed by contacting the upstream seat portion, and the upstream fuel passage is opened by separating the upstream seat portion;
   A downstream valve seat in which the downstream fuel passage is closed by contacting the downstream seat portion and the downstream fuel passage is opened by separating the downstream seat portion; and
   An urging member that urges the valve body in a direction in which the upstream seat portion contacts the upstream valve seat;
   A driving element that drives the valve body in a direction in which the downstream seat portion contacts the downstream valve seat;
   With
   Fuel injection for injecting fuel by driving the valve element with the drive element in a state where the upstream seat portion is separated from the upstream valve seat and the downstream seat portion is separated from the downstream valve seat valve.
2. The fuel injection valve according to claim 1, wherein
   An upstream biasing force including a biasing force of the biasing member that biases the valve body in a direction in which the upstream seat portion is in contact with the upstream valve seat when the drive element is not energized. However, the fuel injection valve is configured to be larger than a downstream biasing force that biases the valve body in a direction in which the downstream seat portion comes into contact with the downstream valve seat.
3. The fuel injection valve according to claim 2,
   By driving the drive element so that the downstream biasing force including the driving force of the drive element is larger than the upstream biasing force during energization of the drive element, the downstream sheet portion is A fuel injection valve characterized by closing a downstream fuel passage in contact with a downstream valve seat.
4. The fuel injection valve according to claim 3,
   The drive element is provided on the opposite side of the upstream seat portion from the side on which the downstream seat portion is provided,
   A relay portion that relays between the drive element and the upstream side seat portion; and a bellows member that is provided radially outward of the relay portion and encloses the relay portion,
   The fuel injection valve, wherein the bellows member is assembled in a compressed state from an initial state of natural length.
5. The fuel injection valve according to claim 3,
   A nozzle body containing the valve body,
   The fuel injection valve according to claim 1, wherein an inner diameter of the nozzle body increases toward an upstream side.

Images