JP2009180182A - Method and device for working nozzle-hole of fuel injection nozzle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for working a nozzle-hole of a fuel injection nozzle by which shape precision of the injection hole is ensured at low cost without causing breakage of punches. <P>SOLUTION: The device for working a nozzle-hole of a fuel injection nozzle is provided with a die 43 for mounting a work 40 for a plate 10 with an injection hole, the punch 41 for punching the injection hole 30, a punch guide 42 holding the punch 41 freely slidably, and a punch-driving means for moving the punch 41. In the punch 41, a cylindrical part 41a is formed in its tip, and a truncated cone part or an elliptic cone part is formed in continuation with the cylindrical part 41a. The cylindrical part 41a and the truncated cone part or the elliptic cone part 41b are connected each other in the respective outlines, and the outline of the truncated cone part or an elliptic cone part 41b constitutes one straight line 41e parallel with the axis 41d of the cylindrical part 41a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an injection hole machining apparatus and an injection hole machining method for a fuel injection nozzle, and, for example, an injection hole machining apparatus and an injection hole for an injection nozzle used for a fuel injection valve that injects fuel to an internal combustion engine for an automobile. It is suitable for application to a processing method.

  2. Description of the Related Art An electromagnetic fuel injection valve (see FIG. 3) is known in which a thin plate with an injection hole formed with a plurality of injection holes is provided at the tip of a fuel injection valve and fuel is injected from each injection hole. In recent years, there is an increasing need for atomization of atomized fuel in electromagnetic fuel injection valves. To meet this need for high atomization, until now, this has been done by miniaturizing the nozzle holes formed in the plate with the nozzle holes.

  In general, the nozzle holes formed in the plate with the nozzle holes have the same diameter from the fuel inlet to the fuel outlet, but in US Pat. No. 4,907,784, the diameter is from the fuel inlet to the fuel outlet. An injection hole-formed plate in which a tapered injection hole is formed is disclosed. Highly atomized fuel spray is promoted by the tapered nozzle holes.

  As a nozzle hole processing method for forming a tapered nozzle hole in a workpiece for a plate with nozzle holes, extrusion molding using a punch can be considered. In the extrusion molding using this punch, if the center axis of the nozzle hole is a taper hole inclined with respect to the normal of the workpiece (material) surface of the plate with the nozzle hole, that is, a perpendicular perpendicular to the workpiece surface, the punch There is a possibility that punch breakage may occur due to a lateral force (force perpendicular to the center axis of the punch) generated when the tip hits the plate-like material. This countermeasure technique is described in Patent Documents 1 and 2.

  A punch 80 of Patent Document 1 is shown in FIGS. FIG. 9 shows a processing process using the punch 80. The punch 80 eliminates the problem (see FIG. 8B) that the normal taper type punch 70 (see FIG. 8) breaks at the tapered portion at the end of the injection hole punching. The punch 80 has a truncated cone portion or an elliptical truncated cone portion (hereinafter simply referred to as a “conical truncated portion”) 80 a formed at the tip thereof, and a cylindrical portion 80 b that is a punch base portion continuously from the truncated cone portion 80 a. Further formed. The frustoconical part and the columnar part are continuously connected to each other, and the outline of the truncated cone has one straight line 80d parallel to the axis 80c of the columnar part. That is, the straight line 80d is combined with a part 80e of the outline of the cylindrical portion to form one straight line 80f. In other words, the punch 80 has an outline in which one straight line 80f is formed across both the truncated cone part 80a and the cylindrical part 80b.

  With this structure, as shown in FIG. 7, the punch 80 transmits a side force Fs to the inner wall side of the nozzle hole by a curved surface including one straight line 80f when punching the nozzle hole, and further, a reaction force of the side force Fs. Fr is received by the curved surface including one straight line 80f from the inner wall of the nozzle hole. For this reason, the punch 80 is hardly subjected to a bending moment due to the side force Fs, and the problem of breaking at the tapered portion is reduced.

  However, as shown in FIG. 9B, when the punch 80 enters the workpiece 40, the portion of the meat 40b that is to become the nozzle hole edge of the workpiece 40 is drawn in the direction of the arrow by the tip of the punch. That is, the acute-side meat 40b at the edge of the nozzle hole of the workpiece 40 is drawn in the direction of the workpiece mass 40d that is displaced by the truncated cone portion 80a. The workpiece mass 40d is finally detached from the workpiece. As a result, the meat 40b that should be present at the hole edge of the workpiece 40 is lacking, and so-called “sag” occurs on the acute angle side (40b) of the nozzle hole edge of the workpiece 40. This “who” adversely affects spray uniformity.

  The punch of patent document 2 is shown in FIG. The processing method described in Patent Document 2 includes a first processing step (FIG. 10A) and a second processing step (FIG. 10B). First, in the first machining step, the first punch 91 is advanced toward the workpiece 40, and a hole 90a having a diameter substantially the same as the outer diameter of the punch is formed in the workpiece 40. Next, the workpiece 40 is conveyed. Thereafter, in the second processing step, the second punch 92 having the tapered portion 92a is advanced toward the hole 90a. Thereby, in forming the tapered injection hole 30, the side surface of the tapered portion 92 a comes into contact with the workpiece 40 (the edge portion of the hole 90 a) before the tip end portion of the second punch 92, and thus acts on the second punch 92. It seems that the bending moment can be reduced as much as possible and the second punch 3 can be prevented from breaking.

  However, as shown in FIG. 11A, the relative position of the punch hole 90a after the workpiece conveyance after the first machining step with respect to the second punch guide guide hole 42a may be shifted (displaced) from the normal position. . This positional deviation amount is represented by x. In this case, the 2nd punch 92 may collide with the peripheral part 90b of the punch hole 90a of a workpiece | work, and the front-end | tip part may bend (refer FIG.11 (b)). Furthermore, since the technique described in Patent Document 2 uses two types of individual punches to open the nozzle holes in two steps, the processing time becomes long and the manufacturing cost increases.

JP 2003-90276 A Japanese Patent Laid-Open No. 2003-245736

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an injection hole machining apparatus for a fuel injection nozzle, which is low in manufacturing cost and does not break a punch, and can ensure the shape accuracy of the injection hole. A nozzle hole processing method is provided.

The present invention provides, as means for solving the above-mentioned problems, an injection hole machining apparatus and an injection hole machining method for a fuel injection nozzle according to each of the claims.
According to the invention described in claim 1, the injection hole machining device for the fuel injection nozzle comprises:
The punch 41 has a cylindrical portion 41a formed at the tip thereof, and a truncated cone portion or an elliptical truncated cone portion is further formed continuously to the cylindrical portion 41a. The cylindrical portion 41a and the truncated cone portion or the elliptical truncated cone portion 41b are Each of the contours is continuously connected to each other, and the contour of the truncated cone portion or the elliptical truncated cone portion (hereinafter simply referred to as “the truncated cone portion”) 41b is one parallel to the axis 41d of the cylindrical portion 41a. It has a straight line 41e.

  The machining apparatus according to the present invention has one type of punch, and by using this machining apparatus, it is possible to open a nozzle hole in a work in one step. Thereby, the cost for opening a nozzle hole in a workpiece | work becomes low. The punch 41 has an outline in which one straight line 41f is formed across both the cylindrical portion 41a and the truncated cone portion 41b. As a result, the punch hardly receives a bending moment due to the side force Fs, and the problem of breakage is reduced. The above are almost the same effects as the technique described in Patent Document 1.

  On the other hand, in the processing apparatus according to the present invention, a guide hole for forming an injection hole is first formed by the cylindrical portion 41a formed at the tip of the punch. The cylindrical portion 41a has an elongated shape, and its volume is smaller than that of the truncated cone portion 41b. For this reason, when the punch cylindrical part 41a enters the workpiece, no “sag” occurs. After the punch cylindrical part 41a enters the work and forms a guide hole, the punch truncated cone part 41b formed adjacent to the cylindrical part 41a is guided by the guide hole and enters the work. At this time, since the guide hole is already clear, the truncated cone portion does not draw in the meat on the acute angle side of the nozzle hole edge. Thus, even when the punch truncated cone part enters the workpiece, no “sag” is generated. That is, no “sag” occurs due to punching.

  According to a second aspect of the present invention, there is provided an injection hole machining method for a fuel injection nozzle, wherein the injection hole is punched using the injection hole machining device according to the first aspect. The processing method using the nozzle hole processing apparatus according to the present invention is also clarified to be within the scope of the claims.

  In addition, the code | symbol of said each means shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining an injection hole machining method according to the present invention, FIG. 2 is a view showing a punch which is a part of an injection hole machining apparatus according to the present invention, and FIG. It is sectional drawing of the electromagnetic fuel injection valve provided with the attached plate.

(First embodiment)
As shown in FIG. 3, the electromagnetic fuel injection valve 100 according to the present invention has a function (a plate 10 with an injection hole) that promotes atomization of the sprayed fuel injected into the intake port of the gasoline engine. The number of electromagnetic fuel injection valves 100 corresponding to the number of cylinders of the engine is assembled to the intake pipe.

  The electromagnetic fuel injection valve 100 includes a plate 10 with an injection hole for forming fuel spray at a lower end portion thereof, and a nozzle needle 8 that can move in the axial direction for opening and closing the fuel passage 9. When the solenoid coil 4 is energized, the nozzle needle 8 rises and the fuel passage 9 is connected to the outside of the injection valve through the injection hole (fuel passage is opened), and high-pressure fuel is injected to the outside. When the energization of the solenoid coil 4 is completed, the nozzle needle 8 is lowered and seated by a spring, the fuel passage 9 is closed, the injection hole is closed (fuel passage closed), and the high-pressure fuel injection is finished. Since the basic structure and operating method of the electromagnetic fuel injection valve 100 are well known, detailed description thereof is omitted here.

  Next, the structure of the nozzle holed plate 10 according to the present embodiment will be described with reference to FIGS. Here, FIGS. 4A and 4B are views showing the nozzle hole shape of the plate with the nozzle holes. FIG. 4A is also a partially enlarged view of the plate portion with the injection holes arranged at the lower end portion of the electromagnetic fuel injection valve of FIG. 3, and shows a cross section of the plate with the injection holes. FIG. 4B is a bottom view of the injection hole plate 10.

  The injection hole plate 10 is fixed to the front end surface of the valve body 7 using welding means such as laser welding so as to close the round hole-shaped opening 29 formed in the lower end surface (front end surface) of the valve body 7. Has been. The injection hole plate 10 is made of a metal material such as SUS. The plate 10 with nozzle holes is formed with a plurality of nozzle holes 30a to 30d that control the direction of the sprayed fuel and promote atomization of the sprayed fuel. These nozzle holes 30a to 30d are opened by the taper-shaped forming process (the nozzle hole process) in the press 1 process according to the present invention, and the central axis of the electromagnetic fuel injection valve 100 (plate 10 with the nozzle holes) is defined. Four are arranged on the circumferential imaginary line of the one-dot chain line at the center.

  The plurality of injection holes 30 a to 30 d are respectively predetermined in a direction in which the central axis of the electromagnetic fuel injection valve 100 returns upstream from the fuel flow direction of the fuel passage 9 from the fuel inlet 31 toward the fuel outlet 32. It is formed through the injection hole plate 10 so as to be inclined by an inclination angle and gradually spread from the fuel inlet 31 toward the fuel outlet 32. That is, each nozzle hole 30 a to 30 d has a tapered cross section that gradually widens from the fuel inlet 31 toward the fuel outlet 32.

  And each nozzle hole 30a-30d is formed so that it may leave | separate from the perpendicular (center axis line) 33 orthogonal to the plate 10 with nozzle hole toward a fuel injection direction. The shape and size of each nozzle hole 30a-30d are the same, and the sizes of θ1, θ2, and θ3 described later of each nozzle hole are equal. The nozzle hole 30a and the nozzle hole 30b, and the nozzle hole 30c and the nozzle hole 30d are formed in the same direction with respect to the central axis 33 of the plate 10 with nozzle holes. The direction in which fuel is injected from the nozzle holes 30a and 30b and the direction in which fuel is injected from the nozzle holes 30c and 30d are opposite to each other by 180 °, and the electromagnetic fuel injection valve 100 performs two-way injection.

  Here, as shown in FIG. 5, a virtual plane that includes the nozzle hole central axis 34 and orthogonal to the plate 10 with nozzle holes, and an inner peripheral surface of the nozzle hole of the plate 10 with nozzle holes that forms the nozzle holes 30 a to 30 d. 35, the first inclination formed by the first axis of intersection 36 and the central axis 33 on the obtuse angle side formed by the nozzle hole central axis 34 and the fuel inlet side end surface 38 of the plate 10 with nozzle holes. The angle is θ1, and the second inclination line formed by the second intersecting line 37 and the center axis 33 formed by the injection hole center axis 34 and the fuel inlet side end face 38 of the plate 10 with the injection hole is θ2. Then, there is a relationship of θ1 <θ2. That is, in each of the nozzle holes 30 a to 30 d, the inner peripheral surface 35 of the nozzle hole that is far from the center axis 33 of the nozzle hole-attached plate 10 with respect to the nozzle hole center axis 34 is It is inclined with respect to the central axis 33 rather than the inner peripheral surface 35 of the nozzle hole close to 33.

  If the first inclination angle is θ1, θ1 is set to 5 ° to 55 °, for example. When θ3 = θ2−θ1, θ3 is set to, for example, 5 ° to 30 °. Furthermore, when the thickness of the plate 10 with nozzle holes is t, for example, 0.05 to 0.15 mm is adopted as t.

  Next, an injection hole machining apparatus and an injection hole machining method for an electromagnetic fuel injection valve according to the present embodiment will be described with reference to FIGS. Here, FIGS. 1A to 1C are process diagrams showing an injection hole machining method for an electromagnetic fuel injection valve.

  Here, the nozzle hole processing apparatus for the plate 10 with nozzle holes includes a transport device that sequentially feeds a roll-like plate-like material (workpiece) 40 made of metal such as SUS, which is a material for a plate with nozzle holes, an upper mold, A press die composed of a lower die and an upper die driving device (not shown) for driving the upper die are provided.

  The upper die of the press die includes a punch 41 whose central axis is inclined with respect to a perpendicular (central axis 33) perpendicular to the plate-like member surface, and a punch for supporting the punch 41 so as to be reciprocally movable in the central axis direction. The lower die of the press die has a die 43 that holds the plate-like member 40 between the punch guide 42 after the plate-like member 40 is fed onto the end surface. The punch 41 is formed with a tapered portion 44 having the same shape as the nozzle hole 30 in order to transfer a predetermined nozzle hole shape. Note that the machining apparatus according to the present invention has one type of punch, and by using this machining apparatus, it is possible to make a nozzle hole in a work in one step.

  The shape of the punch 41 will be described in detail with reference to FIG. The punch 41 has a cylindrical part 41a formed at the tip thereof, and a truncated cone part or an elliptical truncated cone part (hereinafter simply referred to as a "conical truncated part") 41b formed continuously from the cylindrical part 41a. A base cylindrical portion 41c is further formed continuously to 41b. The cylindrical portion 41a, the truncated cone portion 41b, and the base cylindrical portion 41c have their respective contours connected continuously to each other, and the contour of the truncated cone 41b has one straight line 41e parallel to the axis 41d of the cylindrical portion 41a. . That is, the punch 41 has a contour in which one straight line 41f is formed across both the cylindrical portion 41a and the truncated cone portion 41b. As a result, the punch hardly receives a bending moment due to the side force Fs, and the problem of breakage at the tapered portion is reduced.

Next, the injection hole machining method will be described with reference to FIG.
First, as shown in FIG. 1, in the press mold, the plate-like material 40 is sandwiched and held between the upper end surface of the die 43 and the lower end surface of the punch guide 42. The punch 41 is moved in the axial direction by punch driving means (not shown) so that the central axis 41g of the punch 41 has a predetermined inclination angle with respect to the plate thickness direction of the plate-like material (workpiece) 40. To drive. Thereby, the punch 41 is caused to enter the workpiece 40 while pressing the cylindrical portion 41a of the punch 41 against the plate-like material 40 fed from the conveying device. Then, the volume of the material corresponding to the cylindrical portion 41a is pushed away from the workpiece 40 by the cylindrical portion 41a formed at the tip of the punch, and the guide hole 40a for forming the injection hole is first formed. The cylindrical portion has an elongated shape, and its volume is smaller than that of the truncated cone portion. For this reason, when the punch cylindrical portion enters the workpiece, the sharp edge side meat 40b of the nozzle hole edge is not pulled in, and no “sag” occurs.

  After the punch cylindrical portion enters the workpiece to form the guide hole 40a, the punch truncated cone portion formed adjacent to the cylindrical portion is guided by the guide hole and enters the workpiece. Then, the material of the volume obtained by subtracting the volume of the guide hole 40a from the volume of the truncated cone part 41b from the work 40 is pushed away by the truncated cone part 41b, and the tapered hole 40c for the injection hole is formed. At this time, since the guide hole 40a is already clear, the truncated cone portion does not pull in the meat 40b on the acute angle side of the nozzle hole edge. Thus, even when the punch frustoconical portion enters the workpiece, no “sag” occurs at the nozzle hole edge. That is, no “sag” occurs due to punching.

  And the unnecessary part 40d for the volume which the taper part 41b of the punch 41 pushed away remains on the opposite surface where the taper part 44 of the punch 41 of the plate-shaped material 40 was pressed. Next, the unnecessary portion 40 d is removed at the height position of the plate-like material 40. Thereby, the desired nozzle hole shape, that is, the tapered nozzle hole 30 whose diameter increases from the fuel inlet 31 toward the fuel outlet 32 can be formed.

  With this nozzle hole processing method, it is possible to realize a low-cost and high-productivity nozzle hole processing method, and it is possible to form a nozzle hole that ensures shape accuracy and flow rate accuracy.

  Then, when the number of the above-mentioned nozzle holes arranged for one plate with the nozzle holes is opened, the plate-like material 40 is conveyed by one step on the lower mold. When the injection hole processing for one plate-shaped material roll is completed by repeating such injection hole processing, the plate-like material 40 is punched out with a punch corresponding to the circular outer shape 10a of the injection hole plate, and individual injection holes are attached. Manufacture plates. In this way, it is possible to manufacture a plate with injection holes having tapered injection holes 30 that gradually spread from the fuel inlet 31 toward the fuel outlet 32.

  The taper portion 41b of the punch 41 has a taper oblique shape (substantially elliptic cone shape) having a first inclination angle θ1 and a second inclination angle θ2 with respect to a perpendicular (center axis line 33) perpendicular to the plate-like material surface. Have. The punch guide 42 is formed with a support hole 42a for covering the entire circumference of the punch 41 and for supporting the punch 41 slidably so that the central axis 41g is inclined with respect to the workpiece 40. ing. In the die 43 on which the plate-like material 40 is placed on the upper end surface, a discharge hole 43a through which the unnecessary portion 40d of the workpiece 40 can be discharged is formed in the die 43.

  In this way, it is possible to provide an injection hole machining apparatus and an injection hole machining method for a fuel injection nozzle that are low in manufacturing cost and do not break the punch and can ensure the shape accuracy of the injection hole.

It is a figure explaining the nozzle hole processing method which concerns on this invention. It is a figure showing the punch which is a part of the nozzle hole processing apparatus which concerns on this invention. It is sectional drawing of the electromagnetic fuel injection valve provided with the plate with an injection hole. (A) is the elements on larger scale of FIG. 3, (b) is a bottom view of a plate with a nozzle hole. It is detail drawing of a nozzle hole. It is a conventional nozzle hole processing apparatus (patent document 1). It is a figure showing the acting force concerning a punch of FIG. It is another conventional nozzle hole processing apparatus. It is a figure showing the processing process implemented using the nozzle hole processing apparatus of FIG. It is a figure explaining the conventional nozzle hole processing method (patent document 2). It is a figure explaining the malfunction in the nozzle hole processing method of FIG.

Explanation of symbols

10 Plate with Hole 40 Workpiece 41 Punch 42 Punch Guide 43 Dice

Claims (2)

An injection hole plate (10) having an injection hole (30) whose inner diameter expands from the fuel inlet part (31) toward the fuel outlet part (32), and the injection hole central axis (34) is the injection hole plate. An injection hole machining device for a fuel injection nozzle (100) comprising an injection hole-attached plate (10) inclined with respect to the plane portion of (10)
A die (43) on which a work (40) for the plate with a nozzle hole (10) is placed, a punch (41) for punching the nozzle hole (30), and the punch (41) are slidable. In the injection hole machining apparatus for a fuel injection nozzle, comprising a punch guide (42) to be supported, and a punch driving means for moving the punch (41).
The punch (41) has a cylindrical part (41a) formed at the tip thereof, and a truncated cone part or an elliptical truncated cone part (41b) is further formed continuously to the cylindrical part (41a).
The cylindrical part (41a) and the truncated cone part or the elliptical frustum part (41b) are connected to each other in a continuous manner.
The nozzle hole of the fuel injection nozzle, wherein the outline of the truncated cone part or the elliptical truncated cone part (41b) has one straight line (41e) parallel to the axis (41d) of the cylindrical part (41a) Processing equipment.   A nozzle hole machining method for a fuel injection nozzle, wherein the nozzle hole is punched out using the nozzle hole machining apparatus according to claim 1.

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