JP2007051573A - Fuel injection valve and method for manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an orifice satisfying demands for a complicated shape orifice meeting objectives of increase of spray accuracy and functionality of a fuel injection valve, and increasing demand for atomization of spray, and a method for manufacturing the same. <P>SOLUTION: A part of a downstream side inner wall of the orifice in the fuel injection valve is inclined to a center axis line side of the orifice in relation to an upstream side inner wall. Shape of spray can be arbitrarily changed by changing angles of an inclination part and a section forming the inclination part. Also, fuel flowing in the orifice is pressed against the inclination part and easily forms thin film, and spray can be atomized. The orifice can be accurately formed by combining pressing and coining. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel injection valve for injecting fuel into a combustion chamber of an internal combustion engine such as an automobile engine and a method for manufacturing the same.

  A fuel injection valve used for an automobile engine or the like generally has a cylindrical injection hole in which an orifice, that is, a central axis of a fuel passage is parallel to a central axis of an injection valve main body. However, in recent years, in order to improve the accuracy and functionality of the spray, there has been a demand for a fuel injection valve that can realize a complex spray shape that meets the requirements. In addition, fuel atomization has been required. In order to meet these demands, an injection hole in which the orifice is inclined with respect to the central axis of the injection valve body and the fuel is injected in an oblique direction can be seen (for example, see Patent Documents 1 and 2). ). In Patent Document 1, the upstream side of the orifice is formed into a cylindrical shape having a central axis parallel to the central axis of the injection valve body, and the downstream side is inclined in a curved shape with respect to the central axis of the injection valve body to form a curved passage. A fuel injection valve is described. Further, Patent Document 2 describes a fuel injection valve having a nozzle hole whose diameter decreases toward the downstream side by decreasing the punching clearance on the inclined inner side surface of the nozzle hole and increasing the punching clearance on the inclined outer side surface. Yes.

JP 2003-161229 A (summary) JP 2003-245735 A (summary)

  As a method of processing the orifice of the fuel injection valve with high accuracy, there is press processing using a punch. However, in the case of an orifice having a curved passage like the fuel injection valve described in Patent Document 1, pressing is difficult. Patent Document 1 describes that a cylindrical passage is machined using an electric discharge machining or an end mill using a straight electrode rod, and a curved passage is machined using an arc-shaped electrode rod. Yes. Moreover, since electric discharge machining has a large surface roughness, it describes that fluid polishing is performed to finish the surface smooth.

  An object of the present invention is to provide a fuel injection valve capable of applying press working to the formation of an orifice and enhancing the effect of atomizing the fuel, and a method for manufacturing the same.

  The present invention provides a fuel injection valve in which an orifice for injecting fuel is provided at a tip portion, wherein a part of an inner wall on the downstream side of the orifice is inclined toward a central axis of the orifice with respect to an inner wall on the upstream side. And

  In the fuel injection valve in which the orifice is inclined so that the fuel is injected in an oblique direction, a part of the downstream inner wall of the orifice is on the central axis side of the orifice with respect to the upstream inner wall. It is further inclined.

  The present invention relates to a method for manufacturing a fuel injection valve in which a nozzle or an orifice plate is set on a die provided with a die hole, and the orifice is formed with a punch. The portion is coined so that a part of the inner wall on the downstream side of the orifice is inclined toward the central axis of the orifice with respect to the inner wall on the upstream side of the orifice.

  According to another aspect of the present invention, there is provided a fuel injection valve manufacturing method in which an orifice molding plate material is set on a die provided with a die hole, and the orifice is formed by penetrating the punch. After molding, the downstream tip of the orifice is coined using a coining die having coining protrusions, and a part of the downstream inner wall of the orifice is inclined toward the central axis of the orifice with respect to the upstream inner wall. And

  Furthermore, the present invention provides a fuel injection valve manufacturing method in which an orifice forming plate material is set on a die provided with a die hole, and the orifice is formed by penetrating the punch. Using a tilted die, forming a through hole by penetrating the punch from the direction upstream of the orifice and forming a convex portion at a position where the end surface of the die hole is partially tilted, The convex portion is flatly pushed so that a part of the downstream inner wall of the orifice is inclined toward the central axis of the orifice with respect to the upstream inner wall.

  In the fuel injection valve of the present invention, since a part of the inner wall on the downstream side of the orifice is inclined toward the central axis of the orifice, the fuel that has flowed into the orifice is easily pressed into the inclined portion to form a thin film. , Atomization of spray is promoted. Further, the shape of the orifice outlet portion can be arbitrarily changed, and the shape of the spray can be equivalent to the shape of the orifice outlet portion. In the case where the orifice is an inclined nozzle hole, the injection direction is widened by the inclined portion provided on the inner wall on the downstream side of the orifice, so that atomization is further promoted. The fuel injection valve of the present invention can be easily manufactured by performing coining after press working using a punch.

  The present invention is directed to a fuel injection valve having an orifice in which the central axis of the orifice is parallel to the central axis of the injection valve body and an inclined orifice.

  In the case of an inclined orifice, it is particularly desirable that the portion further inclined with respect to the central axis of the orifice is an inclined inner inner wall. Thereby, the spread of spray can be enlarged.

  Examples of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following examples.

  FIG. 1 shows a longitudinal sectional view of a fuel injection valve for an automobile gasoline engine to which the present invention is applied.

  The magnetic circuit that operates the valve includes a core 41, a yoke 42, and a movable valve 43 that form the fuel injection valve body 1. Inside the core 41, there are a movable valve 43 having a valve seat 43 a at its tip, a spring 44 that presses the movable valve 43 against the valve seat portion 10 a of the nozzle 10, an adjuster 45 that adjusts the load of the spring 44, and the movable valve 43. A stopper 46 serving as a stroke end is provided. Furthermore, a swirler 50 that gives a turning force to the fuel, a plate 51 that fixes the swirler 50 to the nozzle 10, a ring 47 that prevents the fuel from leaking from between the core 41 and the yoke 42, and supports a dry coil structure, a magnetic circuit Are provided with a coil 48 for energizing and a terminal bobbin 49 for energizing the coil 48.

  In the fuel injection valve of this embodiment, when the coil 48 is energized, the movable valve 43 moves in the direction of the core 41 against the urging force of the spring 44. Thus, the fuel passes through the core 41, the adjuster 45, the ring 47, the movable valve passages 43b and 43c, the nozzle passage 10b, and the plate passage 51b, is given a turning force by the swirler groove 50b, and is injected from the orifice 11. . When the current of the coil 48 is interrupted, the movable valve 43 is brought into contact with the valve seat portion 10a by the force of the spring 44 to be closed. In this embodiment, the orifice is directly formed on the nozzle 10, but an orifice plate having an orifice may be fitted into the tip of the nozzle.

  The present invention is characterized in the shape of the orifice 11 provided in the nozzle 10 or the orifice plate and the processing method thereof in the fuel injection valve having the above-described configuration.

  An orifice processing method according to an embodiment of the present invention will be described with reference to FIGS. 2 (a) and 2 (b), and the orifice manufactured by the processing method is shown in FIGS. 3 (a) and 3 (b). In this embodiment, a cylindrical orifice in which the central axis of the orifice is parallel to the central axis of the fuel injection valve is formed.

  In forming the orifice, first, as shown in FIG. 2A, the nozzle 10 is set on the die 21 having the die hole 21a. The downstream portion of the orifice 11 is formed by the cylindrical cutting edge portion 20 a of the punch 20. After the punch 20 is pulled out, as shown in FIG. 2B, a predetermined amount of coining is performed on the downstream end face of the orifice 11 with the coining portion 22a using the punch 22 having the coining portion 22a. By coining, the downstream end surface of the orifice 11 is partially deformed, and the inclined portions 11 a and 11 b are formed toward the center of the orifice 11. Thereafter, the valve seat portion 10a is machined by turning or drilling to penetrate the orifice 11, and after quenching, the valve seat portion 10a is finished by grinding.

  FIG. 3A is a front view of the nozzle 10 as viewed from the tip side, and an orifice 11 is provided coaxially with the central axis of the fuel injection valve main body 1 in FIG. FIG. 3B shows a longitudinal sectional view of the nozzle 10 and the orifice 11. The orifice 11 is provided with inclined portions 11a and 11b in the downstream portion over about ½ of the inner circumference of the orifice. In the inclined portion, there is a recess 11c generated when the coining portion 22a of the punch 22 is pushed.

  In the case of the orifice shape shown in FIG. 3, the fuel that has flowed into the orifice 11 through the swirler groove and the valve seat portion 10a is pressed against the inclined portions 11a and 11b to form a thin film, and the spray is atomized. Moreover, the spray which collided with the inclination part and changed the flow direction collided with the fluid which flows along the central axis of an orifice, and atomization of a spray is accelerated | stimulated also by this.

  By providing the inclined portion in a part of the inner wall on the downstream side of the orifice, the spray shape can be changed, and the concentration can be changed in the spray. The spray shape can be arbitrarily set by changing the part forming the inclined part or the inclination angle.

  The orifice of the present embodiment can be easily formed by pressing using a punch and coining. In addition, it is desirable that the inclined inner wall is usually ½ or less of the inner circumference of the orifice, unless a special spray shape is required. If it is more than this, there is a risk that the spray will not spread.

  An example in which the part where the inclined portion is provided is changed is shown in FIGS. The fuel injection valve may be required to have a complicated spray shape suitable for the purpose. 4 (a) and 4 (b) are front views of the downstream end portion of the orifice. FIG. 4A is an example in which the inclined portion 12 a is provided in the remaining most part except for a part of the inner periphery of the orifice 12. This inclined portion can be formed by performing coining using a punch having a coining portion 12c having a shape as shown in FIG. In the case of the orifice shape shown in FIG. 4A, the spray shape is similar to the tip shape, the fuel concentration in the portion where the inclined portion is not provided is relatively high, and the portion where the inclined portion is provided. The fuel concentration is relatively low.

  FIG. 4B shows an example in which inclined portions 13 a are provided at three locations on the inner wall on the downstream side of the orifice 13. This inclined portion can be formed by performing coining using a punch having a coining portion 13c. Also in this case, a spray shape similar to the shape of the tip of the orifice 13 is obtained, the fuel concentration in the portion where the inclined portion is not provided is relatively high, and the concentration in the inclined portion is relatively low.

  In this embodiment, a case where the present invention is applied to an inclined orifice and a method for forming the orifice will be described. FIG. 5 shows an example in which six inclined orifices 61 are processed in the orifice plate 60. It can be considered that this orifice plate is fitted into the nozzle portion at the tip of the fuel injection valve shown in FIG. The orifice in FIG. 5 is shown by a solid line and a dotted line, but the solid line is the upstream inlet of the orifice and the dotted line is the downstream outlet of the orifice.

  6 and 7 show YY cross-sectional views of the orifice of FIG. FIG. 6 shows a conventional example, and FIG. 7 shows the present invention. In the case of a tapered nozzle hole, as shown in FIG. 6, one having a cross-sectional shape with a fractured surface 61 a that widens toward the end is known. In the case of this orifice shape, even though the central axis 61d of the orifice is inclined (about 20 ° to 40 °), it flows directly under a width w between the upper end of the inclined outer inner wall and the lower end of the inclined inner inner wall. There is a fluid flow. As a result, the inclination angle of the spray 80 becomes smaller than the inclination angle of the orifice 61, and there is a problem that the spray is difficult to spread and atomization cannot be achieved.

  FIG. 7 is according to the present invention, and the inclined inner wall on the downstream side of the orifice 61 has inclined portions 61b and 61c inclined further by 5 ° to 15 ° with respect to the central axis 61d of the orifice 61, about 1 of the inner circumference of the orifice. / 2 is formed. For this reason, the central axis 61d of the orifice 61 becomes a further inclined axis 61e on the downstream side. In the case of the orifice of this embodiment, the width of the flow rate flowing directly below becomes w1, the flow rate flowing directly below decreases as apparent from w1 <w, and becomes the inclination angle of the spray 90 along the inclination angle of the orifice 61. In the case of the present embodiment, the fuel is pressed against the inclined portions 61b and 61c to facilitate the thinning, and in addition to the promotion of atomization, the spray is easily spread, so that further atomization can be achieved and good. Can be obtained.

  Next, a method for processing the orifice shown in FIG. 7 will be described.

  An orifice plate 60 made of a plate material for forming the orifice is set on a die 64 having a die hole 64a as shown in FIG. A stripper 63 is set on the orifice plate, and the orifice plate 60 is sandwiched between the die 64 and the stripper 63. The diameter of the die hole 64 a is larger than the punch 62 having the same diameter as the orifice 61 by the punching clearance. The orifice 61 is drilled by the lowering of the cylindrical punch 62.

  When the orifice 61 is drilled, the orifice plate 60 is set on a coining die 66 having a coining protrusion 66a having a length of about a half circumference as shown in FIG. 8B. By pressurizing the orifice plate 60 with the upper plate 65, the vicinity of the downstream side of the orifice 61 is coined.

  By coining, the coining portion 66a of the coining die 66 is pushed into a part of the orifice plate 60, whereby the downstream side of the orifice 61 is locally coined as shown in FIG. 8C. The inclined inner walls of the orifice 61 are formed with inclined portions 61b and 61c that are further inclined with respect to the inclined axis 61e of the orifice 61. In the orifice plate 60, a portion where the coining protrusion 66a of the coining die 66 is pushed is recessed to form a coining portion 60a.

  The angles and sizes of the inclined portions 61b and 61c can be arbitrarily changed by appropriately designing the dimensions of the coining protrusion 66a.

  By processing the orifice as described above, the cross section of the orifice 61 is bent in two steps like the central axis 61d and the inclined axis 61e by the inclined inner wall of the fracture surface 61a and the inclined portions 61b and 61c inside the inclined angle. Shape. Thereby, atomization of fuel can be promoted. The orifice of the present embodiment can be molded with high accuracy and high productivity by pressing and coining.

  When forming the injection hole by punching with a press, there is a limit to the inclination angle of the injection hole that can be processed, and it is difficult to punch at an angle of θ = 45 ° or more. In the present invention, after punching at a limit inclination angle, it is possible to further incline the inner wall of the orifice at an inclination angle by coining so that θ = 45 ° or more.

  Another embodiment relating to a method for forming an orifice having inclined nozzle holes will be described.

  In this embodiment, as shown in FIG. 9A, a die 74 having a die 74 a is installed in the die block 75. The die 74 has a chamfered portion 74b. An orifice plate 70 made of a plate material is set on the die 74 and the die block 75. A stripper 73 is set on the orifice plate 70. In this state, the punch 72 is lowered to punch the orifice 71. At this time, a space is formed between the chamfered portion 74b of the die 74 and the orifice plate 70, and a part of the orifice plate 70 is pushed downward during drilling to become an extruded portion 71a. Further, since the plate thickness is increased by the amount of extrusion, and the crack generation from the die 74 is further delayed, the shear surface of the inner wall of the inclined angle inner side of the orifice 71 is longer than the inner wall of the inclined angle outer side.

  Next, as shown in FIG. 9B, the orifice plate 70 is set on a flat plate lower plate 77 and pressurized by the upper plate 76, so that the pushing portion 71a is flat pressed to be formed into a flat shape.

  As a result, as shown in FIG. 9C, inclined portions 71 c and 71 d that are further inclined with respect to the central axis 71 e of the orifice 71 are formed on the inner wall at the inclination angle of the orifice 71.

  In this processing method, the angle and size of the inclined portions 71c and 71d can be arbitrarily changed by designing the chamfered portion 74b of the die 74 in a timely manner.

  The orifice 71 processed as described above has a shape in which the cross-section is bent in two steps like the central axis 71e and the inclined axis 71f of the orifice due to the inner wall of the inclined surface of the fracture surface 71b and the inclined portion 71c. As a result, the direction of fuel flow is deflected.

The longitudinal cross-sectional view which was the Example of this invention and showed the whole structure of the fuel injection valve. The longitudinal cross-sectional view which showed the manufacturing process of the orifice by this invention. The front view and longitudinal cross-sectional view of a nozzle which have the orifice shape | molded by the method of FIG. The front view which showed another Example of the orifice downstream side tip part shape. The front view of the orifice plate which has an inclined nozzle hole. The longitudinal cross-sectional view which shows the conventional example of the inclined orifice. The longitudinal section which shows the Example by this invention of the inclined orifice. The longitudinal cross-sectional view which showed the manufacturing process of the inclined orifice. The longitudinal cross-sectional view which showed another manufacturing process of the inclined orifice.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel injection valve main body, 10 ... Nozzle, 11 ... Orifice, 11a ... Inclined part, 20 ... Punch, 22a ... Coining part, 60 ... Orifice plate, 60a ... Coining part, 61 ... Orifice, 61a ... Fracture surface, 61b ... Inclined portion, 62 ... punch, 66a ... coining protrusion, 70 ... orifice plate, 71 ... orifice, 71a ... extruded portion, 71b ... broken surface, 71c ... inclined portion, 72 ... punch, 74 ... die, 74b ... chamfered portion.

Claims (17)

  In the fuel injection valve in which an orifice for injecting fuel is provided at a tip portion, a part of the inner wall on the downstream side of the orifice is inclined toward the central axis side of the orifice with respect to the inner wall on the upstream side. Fuel injection valve.   2. The fuel injection valve according to claim 1, wherein an inner wall inclined toward the central axis of the orifice has a half or less of an inner circumference of the orifice.   2. The fuel injection valve according to claim 1, wherein the central axis of the orifice is parallel to the central axis of the injection valve body.   4. The fuel injection valve according to claim 3, wherein the upstream side of the orifice is cylindrical, and the downstream side of the orifice including a portion inclined toward the central axis of the orifice is non-cylindrical.   2. The fuel injection valve according to claim 1, wherein the central axis of the orifice is inclined with respect to the central axis of the injection valve body.   In the fuel injection valve in which the orifice is inclined so that the fuel is injected in an oblique direction, a part of the downstream inner wall of the orifice is further inclined toward the central axis side of the orifice with respect to the upstream inner wall. The fuel injection valve characterized by the above-mentioned.   7. The fuel injection valve according to claim 6, wherein the inner wall further inclined toward the central axis side of the orifice is an inclined inner inner wall of the orifice.   The fuel injection valve according to claim 6, wherein an inner wall further inclined toward the central axis side of the orifice is ½ or less of an inner circumference of the orifice.   7. The fuel injection valve according to claim 6, wherein a central axis on the upstream side of the orifice is shifted from a central axis on the downstream side of the orifice.   7. The fuel injection valve according to claim 6, wherein the flow angle of the fuel is different between the upstream side and the downstream side of the orifice, and the flow direction of the fuel is deflected in the orifice.   In a method of manufacturing a fuel injection valve in which a nozzle or an orifice plate is set on a die provided with a die hole and an orifice is formed by a punch, after the orifice is formed by the punch, the downstream end portion of the orifice is coined. Then, a part of the inner wall on the downstream side of the orifice is inclined toward the orifice central axis with respect to the inner wall on the upstream side of the orifice.   12. The nozzle or orifice plate set on the die according to claim 11, wherein a punch is pushed from the downstream side of the orifice to form a downstream portion of the orifice, and then the periphery of the downstream tip portion is partially A method of manufacturing a fuel injection valve, wherein a part of an inner wall is inclined by coining, and then an upstream portion of an orifice is formed by machining.   12. The method of manufacturing a fuel injection valve according to claim 11, wherein the coining process is performed using a punch having a coining portion.   In a method of manufacturing a fuel injection valve, an orifice molding plate material is set on a die provided with a die hole, and the orifice is molded by penetrating the punch through the orifice molding plate material. After molding, a coining die having coining protrusions is used to coin the downstream tip portion of the orifice, and a part of the downstream inner wall of the orifice is inclined toward the central axis of the orifice with respect to the upstream inner wall. A method for manufacturing a fuel injection valve.   15. The method of manufacturing a fuel injection valve according to claim 14, wherein the periphery of the downstream tip portion of the orifice is partially coined.   15. The orifice material according to claim 14, wherein an orifice is formed by passing a punch through the orifice forming plate material from a direction upstream of the orifice, and then the plate material on which the orifice is formed is set on the coining die for coining. A method of manufacturing a fuel injection valve, characterized by comprising:   15. The orifice forming plate material is set on a die whose end face of the die hole is partially inclined, and the through hole is formed by penetrating the punch from a direction upstream of the orifice. And forming a convex portion at a position where the end face of the die hole is partially inclined, and then flatly pushing the convex portion so that a part of the downstream inner wall of the orifice is the center of the orifice with respect to the upstream inner wall. A method of manufacturing a fuel injection valve, wherein the fuel injection valve is inclined toward the axis.

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