JP2000018135A - Fuel injection valve and manufacturing method for that - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the offset of spray and improve valve sealing performance and the yield, by installing a means for generating swirl in fuel flow at the tip of the valve main body through which a needle valve passes to form the swirl flow generating means integrally at the tip of the valve main body. SOLUTION: A needle valve 12 is fit in a valve main body 9, which is contacted to and detached from a valve seat 11. Detaching motion of the needle valve 12 from the seat opens a fuel injection hole 10 to inject the fuel. In this case, a swirl generation portion 9c is formed in the valve main body 9 to provide a function of the turning body to generate swirl in the injected fuel flow. That is, two path holes 41s, a swirl groove 25 and an internal circumference circular groove 24 are formed in the valve main body 9. Also, high coaxial precision is obtained by simultaneously processing needle valve first and second sliding portions, 9a, 9b formed on the valve main body 9, the fuel is introduced to the swirl groove 25 through an axial direction passage 43 formed between a cylindrical portion 11a of the valve seat 11 and the valve main body 9, to generate the swirling flow.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve for in-cylinder injection, and more particularly to a fuel injection valve of the type in which a swirling means is provided with swirling energy to inject fuel from a fuel injection hole and injected from a fuel injection hole. It is about.

[0002]

2. Description of the Related Art FIG. 6 is a side sectional view showing an entire conventional fuel injection valve for in-cylinder injection, FIG. 7 is an enlarged sectional view of a valve device, FIG. 8 is a bottom view of a revolving body, and FIG. It is an expanded side sectional view of a body peripheral part. In these figures, reference numeral 1 denotes a fuel injection valve for in-cylinder injection, which includes a housing main body 2 and a valve device 3 supported at one end of the housing main body 2 by coupling means such as caulking. A fuel supply pipe 4 is connected to the other end of the housing main body 2, and a tip end of the in-cylinder fuel injection valve 1 is inserted into an injection valve insertion hole 6 of a cylinder head 5 of an internal combustion engine and sealed and attached. . The valve device 3
A stepped hollow cylindrical valve body 9 having a small-diameter cylindrical portion 7 and a large-diameter cylindrical portion 8, a valve seat 11 fixed to the tip of a center hole in the valve body 9 and having a fuel injection hole 10, and a solenoid device A needle valve 12 which is a valve body which opens and closes a fuel injection hole 10 by being separated from and attached to a valve seat 11;
2 in the axial direction and the valve seat 1 inward in the radial direction.
And a revolving body 13 that imparts a revolving motion to the fuel that is about to flow into one of the fuel injection holes 10. The valve body 9 of the valve device 3 cooperates with the housing body 2 to form a housing of the in-cylinder fuel injection valve 1.

Next, in FIGS. 8 and 9, reference numeral 13 denotes a revolving body of the valve device 3. The revolving body 13 slides in the axial direction around a needle valve 12 which is a valve body at the center thereof. A substantially hollow cylindrical member having a central hole 15 for supporting it, the first end face 16 contacting the valve seat 11 when assembled in the valve device 3, and a second end face opposite the valve seat 11. An end surface 17 and a peripheral surface 19 between these end surfaces and in contact with an inner peripheral surface 18 of the valve body 9 which is a part of a hollow housing are provided. Then, the second end face 17 of the revolving body 13
Are supported in contact with the shoulder 20 of the inner peripheral surface 18 of the valve body 9 at the periphery thereof, and the radially extending passage grooves 21
Are formed so that fuel can flow from the inner peripheral portion to the outer peripheral portion of the second end face 17. A plurality of outer peripheral surface portions 2 that abut on the inner peripheral surface 18 of the valve body 9 to define the position with respect to the valve body 9 are provided on the peripheral surface 19 of the revolving body 13.
9 and a flow path portion 23 which is a flat surface provided between the outer peripheral surface portions 29 and forms the fuel axial flow path 22 together with the inner peripheral surface 18. These axial flow paths 22 are formed between the inner peripheral surface 18 of the valve body 9 and the flat flow path portion 2.
3, the cross-sectional shape is a one-sided convex lens shape. Note that these axial flow paths 22 are 6 in the illustrated example.
Although the number is provided, four or eight may be provided.

Further, as shown in FIG. 8, the revolving body 13 has an axial end face facing the valve seat 11, that is, a first end face 1 as shown in FIG.
On the sixth side, an inner circumferential annular groove 24 having a predetermined width formed in the inner periphery adjacent to the center hole 15, and a flow path portion 23 of the circumferential surface 19 at one end.
And a turning groove 25 extending substantially radially inward therefrom and connected tangentially to the inner circumferential annular groove 24 at the other end. The number of the turning grooves 25 is six in the illustrated example, but may be four, eight, or more. In addition, in FIG.
7 is a coil, 28 is an amateur.

Next, the operation will be described. In the in-cylinder fuel injection valve 1 having the above configuration, the coil 2
When power is supplied to the armature 7, a magnetic flux is generated in a magnetic path formed by the armature 28, the core 26, and the housing body 2, the armature 28 is attracted to the core 26 side, and the needle valve 12 which is an integral structure with the armature 28 A gap is formed away from 11. Then, the high-pressure fuel flows from the valve body 9 through the passage groove 21 on the second end face 17 of the revolving body 13 and the axial flow path 22 on the peripheral surface, and into the swirl groove 25 on the first end face 16. And flows inward in the radial direction, and the first end face 1
6 flows in the tangential direction toward the inner peripheral annular groove 24, enters the injection hole 10 of the valve seat 11 as a swirling flow, and is sprayed from the tip outlet.

[0006]

In the above-described fuel injection valve, the valve seat 11 of the needle valve 12 is provided.
In order to obtain a good valve sealing property when seated on the needle, it is necessary to prevent the needle valve 12 and the revolving body center hole 15 from interfering with each other when the valve is opened. However, if the clearance between the center hole 15 of the revolving structure and the outer diameter 12a of the needle valve is increased in order to prevent this interference, the spray is biased because the needle valve has an inclination when the valve is opened. In particular, when the shape of the spray directly affects the combustion performance of the engine as in the case of a fuel injection valve for in-cylinder injection, it is important to suppress the eccentricity of the spray. Therefore, in order to prevent bias of the spray and obtain good sealing performance when the valve is closed, the amount of the gap between the revolving structure center hole 15 and the needle valve outer diameter 12a is set to be equal to or less than the amount of the gap where the spray is not eccentric, and By making the concentricity between the inner diameter 9a of the valve body, which is the first sliding portion of the needle valve, and the center hole 15 of the revolving structure, which is the second sliding portion, high, the center hole 15 of the revolving structure and the outer diameter 12a of the needle valve are improved. It is necessary to prevent interference when the valve is opened. Therefore, in order to make the coaxiality between the inner diameter of the valve body and the center hole of the revolving structure after the revolving structure is assembled to the valve body highly accurate, the valve body and revolving structure before assembly are finished with very high precision and assembled. Was. However, in order to make the coaxiality between the inner diameter of the valve body and the center hole of the revolving structure high, it is problematic in terms of cost to finish each part with very high precision. Further, even if the accuracy of the single body of the valve body and the revolving unit is high, deformation and eccentricity occur during assembly. For example,
When the valve body and the revolving body are press-fitted, eccentricity, deformation or the like at the time of press-fitting occurs. When the revolving body is fitted in the valve body with a gap, eccentricity corresponding to the gap occurs. Here, there is also a method of reducing the eccentricity by stratifying the inner diameter of the revolving body insertion portion and the outer diameter of the revolving body of the valve body according to dimensions and determining a combination so that the amount of the gap becomes a small value. The point becomes a problem. As described above, no matter how much the accuracy of a single unit is improved, there is a limit to achieving high accuracy in the coaxiality between the inner diameter of the valve body and the center hole of the revolving unit after assembly. Is a difficult problem.

[0007] The present invention solves the above problems,
It is an object of the present invention to provide a fuel injection valve which can improve the yield by improving the valve sealability while preventing the eccentricity of the spray and can be obtained at low cost, and a method for manufacturing the same.

[0008]

According to a first aspect of the present invention, there is provided a fuel injection valve having a means for generating a swirling flow in a fuel flow at a distal end of a valve body through which a needle valve passes. In the above, the portion that generates the swirling flow is formed integrally with the distal end portion of the valve main body instead of as a separate component.

According to a second aspect of the present invention, there is provided a fuel injection valve.
The entire valve body was manufactured by metal powder injection molding.

According to a third aspect of the present invention, a fuel injection valve is provided.
Of the valve body, the part that gives the swirling flow is manufactured by metal powder injection molding, the other part is manufactured by processing other than metal powder injection molding, and both are fixed by welding etc. to form an integral part It is.

According to a fourth aspect of the present invention, there is provided a fuel injection valve.
A gap provided between the outer peripheral portion of the swirling flow generating portion of the valve body and the inner peripheral portion of the cylindrical portion of the valve seat is used as an axial passage for fuel.

According to a fifth aspect of the present invention, a fuel injection valve is provided.
The number of passage holes for transporting fuel from the inner peripheral side to the outer peripheral side of the swirling flow generating unit is equal to or less than the number of swirling grooves or portions corresponding thereto.

According to a sixth aspect of the present invention, in the method for manufacturing a fuel injection valve, the needle valve sliding portion (first sliding portion) of the valve body and the inner diameter portion (second sliding portion) of the swirling flow generating portion are formed. They are processed simultaneously.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a first embodiment. FIG. 1 is a side sectional view of the entire in-cylinder fuel injection valve, and FIG. 2 is an enlarged sectional view of a valve device portion of FIG.
(a) and its cross-sectional view (b). In these figures,
Reference numeral 1 denotes a fuel injection valve for in-cylinder injection, which includes a housing body 2 and a valve device 3 supported at one end of the housing body 2 by coupling means such as caulking. Housing body 2
A fuel supply pipe 4 is connected to the other end of the fuel injection valve, and a distal end of the in-cylinder fuel injection valve 1 is inserted into an injection valve insertion hole 6 of a cylinder head 5 of the internal combustion engine, and is sealed and mounted.
The valve device 3 includes a stepped hollow cylindrical valve body 9 having a small-diameter cylindrical portion 7 and a large-diameter cylindrical portion 8, and a valve seat 11 having a fuel injection hole 10 fixed to a tip of a center hole in the valve main body 9. And the fuel injection hole 10 is separated from and connected to the valve seat 11 by the solenoid device.
A needle valve 12 which is a valve element for opening and closing the valve, and a swivel that guides the needle valve 12 in the axial direction and gives a swirling motion to the fuel that is about to flow radially inward into the fuel injection hole 10 of the valve seat 11. And a flow generating portion 9c (to be described in detail later). The valve body 9 of the valve device 3 cooperates with the housing body 2 to form the housing of the in-cylinder fuel injection valve 1. 26 is a core, 27 is a coil, 28
Indicates an amateur. In this embodiment, portions other than the valve device are the same as those in the above-described conventional example.

Here, the valve device of the present embodiment will be described. The configuration of the valve device 3 of the fuel injection valve 1 includes the valve seat 11, the needle valve 12, the valve body 9, and the like. The function of the body 13 is provided to a swirling flow generating portion 9c formed integrally with the valve body 9. That is, two passage holes 4 corresponding to the passage grooves 21 of the revolving body are provided in the valve body 9.
1 and a revolving groove 25 and an inner peripheral annular groove 24 similar to the revolving body.
Is provided. It is sufficient that the number of the passage holes 41 is sufficient to obtain a sufficient flow passage area. Therefore, the number of the passage holes 41 is two in the present embodiment (however, the number of the passage holes 41 is not limited to two). Further, in the conventional example, the revolving body center hole 15 forms the second sliding portion of the needle valve 12, but in the present embodiment, the valve body 9 is provided with the needle valve second sliding portion 9b. The first sliding portion 9a of the needle valve and the second sliding portion 9b of the needle valve are simultaneously processed to obtain high coaxial accuracy. The valve seat 9 has a valve body 9.
A cylindrical portion 11a is provided for connection with the valve body 9, and an axial flow path 43 is provided between the valve body 9 and the valve seat cylindrical portion 11a.

Next, the flow of the fuel will be described. Coil 27
When the needle valve 12 integral with the armature 28 is sucked toward the core 26 and the needle valve 12 is separated from the valve seat 11 to form a gap, the fuel first passes through the passage hole 41 and passes through the peripheral surface. Flows into the swirl groove 25, flows radially inward, flows tangentially into the inner annular groove 24, and forms a swirl flow into the injection hole 10 of the valve seat 11. And spray it from the tip outlet.

In the configuration of the present embodiment, the needle valve first sliding portion 9a and the second sliding portion 9b are connected to the swirling flow generating portion 9c.
After fixing the valve body 9 integral with the other parts and the other parts, it may be processed simultaneously. As described above, by simultaneously processing the needle valve first sliding portion 9a and the second sliding portion 9b,
Since the coaxiality of the two can be obtained with high accuracy and the eccentricity of the spray and the defective valve seal can be prevented, the yield can be improved. Further, unlike the related art, it is not necessary to assemble the valve body and the revolving unit with high precision, so that the cost can be reduced. In addition, although the axial flow path is obtained by cutting the outer periphery of the revolving structure on the six surfaces in the conventional example, by forming this as a flow path with a circumferential gap, the six-surface cut becomes unnecessary. Processing becomes simple and cost reduction can be realized. Further, in the conventional example, six passage grooves are provided, but in the present embodiment, only two passage holes need be provided, so that processing is simplified and cost reduction can be realized. Note that FIG.
As shown in FIG. 2, the valve seat of FIG.
It may be configured as a separate component from the above.

Embodiment 2 FIG. In the second embodiment,
The entire valve body 9 in which the swirling flow generating section 9c is integrated is manufactured by metal powder injection molding. In this way, production can be performed at low cost while ensuring the same dimensional accuracy and wear resistance as during cutting. Further, it is possible to produce a shape that is difficult to produce by cutting, and it is also possible to prevent burrs generated during cutting.

Embodiment 3 In the third embodiment, as shown in FIG. 4, a swirl flow generating portion 9c for giving a swirl flow to fuel, out of the valve body in FIG. Is manufactured by metal powder injection molding, the other parts are manufactured by cutting, and the two parts are assembled and fixed by means of welding A or the like to form an integrated structure. As a result, the part with a complicated shape that gives a swirl flow to the fuel can be manufactured by metal powder injection molding, and the other parts with a simple shape can be made by cutting, enabling low-cost production. Becomes In this case, as shown in FIG. 5, the cylindrical portion of the valve seat and the seat portion may be formed as separate parts.

The turning groove 25 may not have a uniform depth, but may change from the outer periphery to the inner periphery. Alternatively, an oblique hole provided in the valve body 9 may be used. Further, the contact surface between the valve body 9 and the valve seat 11 may not be flat, but may be a part of a conical surface. That is, in this case, since the groove can be inclined with respect to a plane perpendicular to the injector axis, a component in the injector axial direction can be given to the fuel together with a swirling direction component.

[0021]

According to the first and fourth to sixth aspects of the present invention, after the valve body including the swirling flow generating portion and other portions are fixed, the first sliding portion of the needle valve and the second sliding portion are simultaneously formed. By processing, the coaxiality of both can be obtained with high accuracy, eccentricity of spray and defective valve seal can be prevented, and many excellent effects such as easy processing and significant cost reduction can be achieved. Play.

According to the second aspect of the present invention, it is possible to produce at low cost while ensuring the same dimensional accuracy and wear resistance as at the time of cutting, and it is possible to produce a shape which is difficult to produce by cutting. Also, generation of burrs can be prevented.

According to the third aspect of the present invention, the cost of the valve body can be reduced by separately processing the swirl flow generating portion having a complicated shape and the other portion having a simple shape.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an entire fuel injection valve according to Embodiment 1 of the present invention.

FIG. 2 is an enlarged side sectional view (a) and a transverse sectional view (b) showing a valve device portion of the fuel injection valve according to Embodiment 1 of the present invention.

3A and 3B are a cross-sectional view and a cross-sectional view showing a modification of FIG.
(b).

FIG. 4 is an enlarged side sectional view (a) and a transverse sectional view (b) showing a valve device portion according to a third embodiment of the present invention.

5A and 5B are a cross-sectional view and a cross-sectional view showing a modification of FIG.
(b).

FIG. 6 is a side sectional view showing the entire conventional in-cylinder fuel injection valve.

FIG. 7 is an enlarged sectional view of the valve device of FIG. 6;

FIG. 8 is a bottom view of the revolving superstructure shown in FIG. 6;

FIG. 9 is a detailed view of the tip of FIG. 6;

[Explanation of symbols]

1. In-cylinder fuel injection valve, 3 valve device, 9 valve body,
9a first sliding portion, 9b second sliding portion, 9c swirl flow generating portion, 11 valve seat, 12 needle valve, 25 swirl groove, 41 passage hole, 43 axial flow path.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G066 AA02 AB02 AD12 BA36 BA49 BA51 BA55 BA61 CC06U CC14 CC43 CC48 CC66 CD04 CD10 CD14 CE22 4F033 AA13 BA03 CA04 DA01 EA01 FA00 KA03 NA01

Claims (6)

[Claims] 1. A valve body comprising: a valve body; a needle valve penetrating a center portion of the valve body; and a valve seat installed at a tip of the valve body, and swirling around a tip of the needle valve into a fuel flow. A fuel injection valve provided with a means for generating a flow, wherein the swirl flow generating portion for generating the swirl flow is formed integrally with the tip end of the valve body instead of as a separate component. . 2. The fuel injection valve according to claim 1, wherein the valve body is manufactured by metal powder injection molding. 3. The swirl flow generating portion of the valve body is manufactured by injection molding of metal powder, and the other portions are manufactured by processing other than injection molding of metal powder. 2. The fuel injection valve according to claim 1, wherein the fuel injection valve is a part. 4. A gap is provided between an outer peripheral portion of the swirling flow generating portion of the valve body and an inner peripheral portion of the cylindrical portion of the valve seat, and the gap serves as a fuel passage in the axial direction. The fuel injection valve according to any one of claims 1 to 3. 5. The swirling flow generating unit according to claim 1, wherein the number of passage holes for transporting fuel from the inner circumferential side to the outer circumferential side is equal to or less than the number of swirling grooves or portions corresponding thereto. 5. The fuel injection valve according to any one of 4. 6. The method for manufacturing a fuel injection valve according to claim 1, wherein a needle valve sliding portion (first sliding portion) of the valve body and an inner diameter portion (second sliding portion) of the swirling flow generating portion. ). A method for manufacturing a fuel injection valve, comprising: