JPH0626420A - Fuel injection valve - Google Patents

Abstract

PURPOSE:To certainly and stably position a nozzle against a body both in the axial direction and in the diametrical direction by making a contact part formed on the nozzle contact with a tapered part formed on the body. CONSTITUTION:A cylindrical body 5 with a through hole 5c to derive fuel formed on its one end side and a bottomed cylindrical nozzle 7 with injection holes 8a, 8b formed on its bottom part are furnished. Especially, a tapered part 5d formed on the outer periphery of the one end side of the body 5 is furnished. Additionally, the nozzle 7 is furnished with a contact part, and a protruded part 7c formed on the inside of a cylindrical part of the nozzle 7 to face the tapered part 5d of the body 5 is formed by making it contact with the tapered part 5d and by plastic deforming it. Additionally, by making contact with the tapered part 5d, the nozzle 7 is positioned against the body 5 in the diametrical direction and in the axial direction. Consequently, it is possible to certainly and stably position the nozzle 7 against the body 5.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection valve used for injecting fuel into an engine for an automobile, for example. 2. Description of the Related Art Conventionally, as seen in Japanese Utility Model Laid-Open No. 61-97584, an adapter (nozzle) having a passage for guiding fuel in a desired direction is provided at the tip of a fuel injection valve. There is known a technique of adjusting a fuel injection direction from a fuel injection valve to a desired direction. By the way, when a nozzle is provided at the tip of a fuel injection valve, a fuel injection hole formed in the fuel injection valve side and a fuel injection hole formed in the nozzle are provided. Accurately positioning the position of is important for accurately setting the fuel injection direction. However, when a bottomed cylindrical adapter (nozzle) is mounted on the cylindrical body of a fuel injection valve as in the prior art, in order to accurately position the two in the radial direction, the body must be It was necessary to process the cylindrical outer peripheral surface and the cylindrical inner peripheral surface of the adapter (nozzle) with high accuracy. If the cylindrical end face of the body and the cylindrical inner bottom face of the adapter (nozzle) are simply brought into contact with each other to position them, the fuel passage hole on the body side and the adapter (nozzle) side Not only is it difficult to accurately position the fuel passage in the fuel passage, but also the adapter (nozzle) may be displaced in the radial direction after the positioning. In view of the above problems of the prior art, the present invention provides a fuel injection valve in which the positioning of the nozzle with respect to the cylindrical body of the fuel injection valve can be reliably and stably obtained both axially and radially. With the goal. In order to achieve the above object, the present invention provides a cylindrical body having a through hole through which fuel is led out at one end side, and a cylindrical body from the one end side. A fuel injection valve, which is mounted so as to cover the outside of the body, and has a bottomed cylindrical nozzle having an injection hole formed in the bottom for guiding the fuel led out from the through hole in a predetermined direction. A tapered taper portion formed on the outer circumference on the one end side and a protrusion formed inside the cylindrical portion of the nozzle so as to face the taper portion of the body are brought into contact with the taper portion to be plastically deformed. And a contact portion for positioning the nozzle in the radial direction and the axial direction with respect to the body by contact with the tapered portion. It According to the above-described structure of the present invention, the contact portion formed on the nozzle is brought into contact with the taper portion formed on the body so that the nozzle moves in the axial and radial directions. Positioned relative to. In particular, the abutting portion of the nozzle is formed by plastically deforming the protrusion formed inside the cylindrical portion of the nozzle by abutting against the tapered portion of the body. It is automatically and stably positioned on the axis of the taper. In particular, since the nozzle contacts the tapered portion of the body, the nozzle is positioned in the axial direction and the radial direction by the contact between the tapered portion and the contact portion. As described above, according to the configuration of the present invention, the nozzle is reliably and stably positioned with respect to the body in both the axial direction and the radial direction. An embodiment of the fuel injection valve according to the present invention will be described below. FIG. 1 is an overall vertical cross-sectional view of a fuel injection valve according to the present invention. A cylindrical body 5 is caulked and fixed to the lower end edge of the case body 1 in the figure, and the case body 1 is provided with a case body. 1 is a flange portion 2 fixed by caulking to the upper edge in the figure.
a cylindrical iron core 2 having a, an electromagnetic coil 3 arranged on the lower part of the flange 2a on the outer periphery of the iron core 2, a movable core 4 arranged at the lower end of the iron core 2 and moving in the axial direction, A needle-shaped valve body 6 that is coupled to the lower portion of the and slides on the inner wall of the tubular body 5 is provided. FIG. 2 is an enlarged view of the tip portion of the fuel injection valve shown in FIG. 1. The tip portion 6a of the valve body 6 is formed into a rounded, substantially conical shape, and the tip portion 6a is formed. A conical surface 5a is formed on the inner periphery of the body 5 in the position where the is stored. The conical surface 5a is abutted over the entire circumference by a part of the curved surface of the tip portion 6a of the valve body 6, and due to this abutment, it is oil-tightly closed between the valve body 6 and the body 5. There is.
The tip surface 5b of the body 5 has a circular planar shape, and one through hole 5c communicating with the inside is bored at the center of the tip surface 5b, and the peripheral wall of the through hole 5c is connected to the conical surface 5a. The communication hole 5c is for injecting the fuel to the outside of the body 5 after restricting and metering the fuel flow flowing on the conical surface 5a. Further, the body 5 is provided with a cylindrical nozzle 7 having a bottomed end so as to cover the tip surface 5b of the body 5. Inside the nozzle 7, the tip surface 5b of the body 5 is
A facing surface 7a, which is a flat surface facing to, is formed. Two injection holes 8a, 8b of the same diameter that penetrate the end wall of the nozzle 7 are opened at the center of the facing surface 7a, and the diameter thereof is
The holes 8a and 8b have a diameter larger than that of the through hole 5c and are formed so as to widen by an angle θ in two directions toward the downstream side where the fuel flows. The two injection holes 8a and 8b have their respective inlet openings overlapped with each other in a portion facing the through hole 5c, and are completely branched into two holes from the middle of the nozzle 7 toward the outlet closing direction. Both holes 8a and 8b are provided between the two holes 8a and 8b from the branch point to the tip of the nozzle 7.
A central partition wall 7b that separates the two is formed. The outer circumferences of the ends of the nozzle 7 and the body 5 are covered with a sleeve 9 having a heat insulating effect. The operation of the solenoid valve having such a structure will be briefly described. When an injection signal is supplied to the fuel injection valve shown in FIGS. 1 and 2 from a computer (not shown), the electromagnetic coil 3 is excited to generate an electromagnetic force and attract the movable core 4 toward the iron core 2. Then, the tip end portion 6a of the valve body 6 connected to the movable core 4 is separated from the tip end surface 5b of the body 5, is supplied from the upper end opening portion of the iron core 2 and enters the gap between the valve body 6 and the body 5 through the inside of the movable core. The arrived fuel is sprayed out from the through hole 5c, is bisected by the two injection holes 8a and 8b into the same flow rate ratio in the angle θ direction, and is injected into the intake pipe (not shown) outside. Next, a detailed structure and an assembling method of the fuel injection valve shown in FIGS. 1 and 2 will be described. FIG. 3 shows each of the body 5 and the nozzle 7 before assembly of the fuel injection valve. The through hole 5c of the body 5 is
By actually injecting the internal fuel from the through hole 5c,
The diameter that makes the flow rate a predetermined value (for example, about 0.41 m
m). A conical tapered portion 5d is formed on the edge portion of the end surface 5b of the body 5. On the other hand, two injection holes 8a, 8b (diameter 0 ..
A protruding portion 7c protruding inward is formed at the edge of the facing surface 7a on the inner side of the nozzle 7 having a diameter of 8 mm. This projection 7c is brought into contact with the taper portion 5d formed on the body 5 during assembly, and is further pressed to plastically deform the edge portion 7d at the tip to become a contact portion, which is an enlarged view in FIG. As indicated by reference numeral 7d in FIG. 7B, the surface contact with a narrow width is restrained in the circumferential direction, so that a very stable assembled state can be obtained. At this time, the gap between the end surface 5b of the body and the end surface 7a of the nozzle is very small (several μm).
In the following), when the body and the nozzle, which will be described later, are fixed, they further effectively stabilize the assembled state, and the fuel pool between the gaps can be reduced. Although this gap temporarily becomes 0 during plastic deformation, it remains as a very small gap due to springback when the deformation load is removed. The protrusions 7c may be arranged uniformly on the circumference, but as another embodiment, the protrusions 7c may be dispersed and arranged. FIG. 5 is a view showing an embodiment of these various shapes of the nozzle protrusion. 5A and 5B relate to an embodiment having protrusions 7c 'uniformly arranged on the inner circumference of the nozzle 7, and FIG. 5A is a side sectional view.
(B) each shows the bottom view seen from the bottom side of (a). 7
d'denotes the edge portion of the tip of the protrusion 7c '. 5 (c) and 5 (d) relate to an embodiment having projections 7c "dispersedly arranged on the inner circumference of the nozzle 7, wherein (c) is a side sectional view and (d) is. Each of the bottom views as seen from the bottom side of (c) is shown as follows: As shown in FIGS.
When c "is dispersed, the edge portion 7 at the tip of the protrusion 7c" is
It is possible to further reduce the deformation load when d "is plastically deformed at the time of assembly. In order to restrain the body and the nozzle in the circumferential direction to make stable contact, generally, the outer diameter of the body is A method of fitting the nozzle and the inner diameter of the nozzle is used, but in this case, the accuracy of the inner diameter and the outer diameter needs to be several microns or less, which is not a preferable method because the processing cost remarkably increases. In the method for assembling the fuel injection valve provided by the present invention, it is possible to easily and stably contact the body and nozzle of the rough processing precision only by applying additional pressure. Next, a method for assembling and adjusting the nozzle 7 and the body 5 will be described, and Fig. 6 is a view for explaining the principle of the position adjusting method at the time of assembling. b) and (c) are ( The relative positional relationship between the through hole 5c and the injection holes 8a and 8b when the assembly of the body 5 and the nozzle 7 assembled as shown in FIG. When the nozzle 7 is assembled to the body 5, the positional relationship between the through hole 5c of the body 5 and the central partition wall 7b of the nozzle 7 is as shown in FIGS. The fuel injected from the through hole 5c is displaced, and the two injection holes 8a and 8b
Even in an assembled state in which the body 5 is fitted into the nozzle 7 with the nozzle 7 side fixed, the contact surface between the taper portion 5d of the body 5 and the nozzle projection portion 7c Is rotated as the reference plane of the rotational movement, the axis of the through hole 5c of the body 5 is generally slightly deviated from the axis of the reference plane 5, so that the through hole 5c
Can be adjusted by the central partition wall 7b of the nozzle 7 to a desired area ratio between the injection hole 8a side and the injection hole 8b side, that is, a relative position for dividing into a desired flow rate ratio, and thus the injection hole 8a side of the through hole 5c. 6C can be adjusted as a position at which the area of 6 is equal to the area of the injection hole 8b side. As described above, according to this method, even if the positions of the nozzle and the hole of the body 5 are slightly deviated from each other due to a processing error or the like, the flow rate ratio between the two injection holes 8a and 8b can be set to a target value. . FIG. 7 is a graph showing the range of the allowable eccentricity in the case of the assembly adjusting method of the present invention in comparison with the range of the allowable eccentricity in the case of the assembly not according to the present invention. Figure 7
As shown in FIG. 5, the eccentricity L of the central partition wall 7b of the nozzle 7 with respect to the central axis of the reference surface 7c and the reference surface 5 of the axial center of the through hole 5c of the body 5 as shown in FIG. The permissible region of the amount of eccentricity M with respect to the shaft center is a shaded portion when it is not rotated, and it is a black portion as a manufacturing instruction allowable error such as a manufacturing drawing. Here, in this example, only the amount of eccentricity L of the central partition wall 7b of the nozzle 7 from the central axis of the reference surface 7c and the amount of eccentricity M of the central axis of the through hole 5c of the body 5 from the axial center of the reference surface 5d are considered. Since this is the case, since the factors such as the angles of the injection holes 8a and 8b and the injection hole diameter must be taken into consideration, the area becomes narrower, and the black portion becomes several microns or less as described above. As described above, the allowable error when not according to the present invention is a very limited area. In order to process in this region, extremely high processing accuracy is required, which is a major factor of cost increase. On the other hand, in the method of adjusting the assembling position by relatively rotating the nozzle and the body using the assembling and adjusting method of the present invention, the permissible error is significantly in the portion of the dot area in FIG. Be expanded to. Therefore, the processing accuracy can be significantly eased and the cost can be reduced. Here, since the nozzle 7 and the body 5 are in very stable contact with each other, it is possible to adjust the position by extremely smoothly changing the deviation between the axes without rattling even when rotating. Next, a specific example of this position adjusting method will be described in detail. The body 5 alone and the nozzle 7 alone are set in an apparatus as shown in FIG. In FIG. 8, 10a is a rotating jig for fixing and rotating the body 5, and 11 is a light source for illuminating the inside of the body 5. The body 5 is fixed to the rotating jig 10a with the through hole 5c as an upper part, and the nozzle 7 is fixed only by the fixing member 10b so that the outlets of the injection holes 8a and 8b are not hidden. It is attached to the body 5 so that it can rotate. The body 5 is rotated inside the nozzle 7 by the work rotating mechanism 12 together with the rotating jig 10a, and the work rotating mechanism 12 is connected to the computer 13 for image processing and rotation control. Above the nozzle 7, there are two injection holes 8a, 8a.
A TV camera 14 for shooting b is provided.
The V camera 14 is connected to the computer 13, and the computer 13 creates a video signal from the TV camera and displays the image on the CRT screen 15. When the light source 11 is turned on, the light from the light source 11 passes through the through hole 5c and further through the two injection holes 8a and 8b, is photographed by the TV camera 14, and is displayed on the CRT screen 15. Since the state where the light passes through the two injection holes 8a and 8b is the same as the state when the fuel flows, the area of the two white parts through which the light passes in the image displayed on the screen 15 is shown. There is a substantially proportional correlation between the ratio and the flow rate ratio when fuel is actually flown. This correlation is based on the shape of the through hole 5c of the body 5 and the two injection holes 8
It is calculated based on the angle θ formed by a and 8b, and the calculation is performed by the computer 13. When the body 5 side is rotated by the work rotating mechanism 12, the computer 13 estimates the positional relationship between the through hole 5c and the central partition wall 7b by the two transmitted lights emitted from the injection holes 8a and 8b. The image at this time is automatically monitored by the computer 13, and the computer 13 stops the rotation on the body 5 side when the nozzle 7 and the body 5 have a desired relative positional relationship. Specific adjusting means will be described with reference to the flowchart of FIG. In FIG. 9, when this assembling process is started in step 60, first, the counter N = 0 is set (step 61), and the area ratio of the transmitted light is measured (step 6).
2). Next, in step 63, the body 5 is rotated by an angle α (α = 20 ° in this example), and the area ratio of the transmitted light is measured again (step 64). Step 63, Step 6
The number of times 4 is counted by incrementing the counter N by 1 (step 65), and in step 66, N is a predetermined value K.
If (K = 19 in this example), that is, the body 5 has been rotated exactly 360 °, the optimum angle that becomes the target area ratio (1 in this example) from the area ratio at each angle. β is calculated (sudp 67), and the body 5 is rotated to the β position (step 68). Then, the area ratio is measured again (step 6).
9) It is determined whether the area ratio is within the standard range (step 70), and if it is within the standard, the process proceeds to step 71, and the nozzle 7 is caulked and fixed to the body 5 at this position. Then, in order to confirm that there is no displacement between the nozzle 7 and the body 5 at the time of caulking and fixing, the area ratio is measured again in step 72 to determine whether it is within the standard ( Step 73), and if it is within the standard, it is judged as a non-defective product (step 74). On the other hand, if it is judged to be out of specification in step 70 or step 73, it is determined as a defective product (step 75). By utilizing the correlation between the area ratio of transmitted light and the actual flow rate of fuel, the nozzle 7 and the body 5 can be measured by measuring the amount of transmitted light without actually flowing the fuel.
And can be extremely easily and quickly adjusted to the relative positions that realize the predetermined flow rate ratio. Even if the positions of the holes formed in the nozzle single body 7 and the body single body 5 in FIG. 3 by the method described above are deviated from the design values due to processing errors, etc. By rotating the body 5 relatively and adjusting to the assembly path, the flow rate ratio of both injection holes 8a, 8b can be set within the target value. Although the light from the light source 11 is used in the above embodiment to measure the flow rate ratio of the injection holes 8a and 8b, air may be used instead of light, or fuel may be actually supplied. Is also good. Further, in fixing the nozzle 7 and the body 5 after the positioning and adjustment in this way, the nozzle 7 and the body 5 are in extremely stable contact with each other, and therefore, by caulking as in the above embodiment. They may be largely deformed and fixed, but they may be joined by caulking without using caulking. FIG. 10 shows an embodiment in which the relative positional relationship between the body 5 and the nozzle 7 is determined by measuring the flow rate ratio of a gas such as air. In FIG. 10, the air flow meter 2
1, the body 5 is rotated by the work rotating mechanism 12 while detecting the flow rate ratio of the two holes 8a, 8b measured by 1.
The rotation of the work is stopped at the position where the desired flow rate ratio is achieved. FIG. 11 shows an embodiment in which the relative positional relationship between the body 5 and the nozzle 7 is determined by measuring the flow rate ratio of a liquid such as fuel. In FIG. 11, the body 5 is rotated by the work rotating mechanism 12 while detecting the flow ratio of the two holes 8a and 8b measured by the fuel flow meter 22, and the rotation of the work is stopped at the position where the desired flow ratio is achieved. Let According to the structure and operation of the present invention described above, the positioning of the nozzle mounted on the outer side of the body of the fuel injection valve can be surely performed with a simple structure in both axial and radial directions. The effect is that it can be performed stably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a fuel injection valve according to an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view of a main part of FIG. FIG. 3 is a vertical sectional view of a nozzle and a valve before assembling. FIG. 4 is a cross-sectional view of a tip portion of a fuel injection valve according to an embodiment of the present invention in which a nozzle is assembled and fixed to a body,
(A) is a cross-sectional view showing an assembled state after assembly, (b) is a portion where the tip edge portion 7d of the projection 7c abuts on the tapered portion 5d of the body 5, and (a) is an enlarged view of portion B in FIG. Sectional view. 5A and 5B show examples of nozzle protrusions having various shapes, and FIGS. 5A and 5B show an embodiment in which protrusions 7c 'are uniformly arranged on the inner circumference of the nozzle 7. FIG. Regarding an example, (a) is a side sectional view, (b) is a bottom view seen from the bottom side of (a), and (c) and (d) in FIG. 5 are dispersed on the inner surface of the nozzle 7. The present invention relates to an embodiment having a protruding portion 7c ″ arranged so that (c) is a side sectional view,
(D) shows the bottom view seen from the bottom side of (c). FIG. 6 is a diagram for explaining the principle of the method for adjusting the position of the assembling path, in which (a), (b), and (c) show the body 5 and the nozzle 7 assembled as shown in (d). Assemble the body 5
Of the through hole 5c and the injection hole 8 as seen from the direction of the arrow in FIG.
The top view which shows the relative positional relationship between a and 8b. FIG. 7 is a graph showing a region of an allowable eccentricity amount in the case of the assembly adjusting method of the embodiment in comparison with a region of the allowable eccentricity amount in the case of assembly not according to the embodiment. FIG. 8 is a configuration diagram of an apparatus that determines the positions of a body and a nozzle by an optical method. 9 is a flowchart showing control performed by the computer 13 of FIG. FIG. 10 is a configuration diagram of an apparatus that determines a relative positional relationship between a body and a nozzle by a flow rate of gas such as air. FIG. 11 is a configuration diagram of an apparatus that determines a relative positional relationship between a body and a nozzle by a flow rate ratio of a liquid such as fuel. [Description of Reference Signs] 5 Body 5c Through Hole 5d Tapered Part 6 Valve Body 7 Nozzle 7c, 7c ', 7c "Projection 7d, 7d', 7d" Edge 8a, 8b Injection Hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sadao Sumiya             Nihonden, 1-1, Showa-cho, Kariya city, Aichi prefecture             Sozo Co., Ltd. (72) Inventor Takumi Noma             Nihonden, 1-1, Showa-cho, Kariya city, Aichi prefecture             Sozo Co., Ltd. (72) Inventor Shinzo Ito             Nihonden, 1-1, Showa-cho, Kariya city, Aichi prefecture             Sozo Co., Ltd. (72) Inventor Takashi Hieda             Nihonden, 1-1, Showa-cho, Kariya city, Aichi prefecture             Sozo Co., Ltd.

Claims (1)

Claims: A cylindrical body having a through hole through which fuel is drawn is formed on one end side, and the one end side of the body is mounted so as to cover the outside of the body, and is led out from the through hole. A fuel injection valve having a bottomed cylindrical nozzle having an injection hole for guiding fuel in a predetermined direction formed in a bottom portion, wherein a tapered taper portion formed on an outer circumference of the one end side of the body, A protrusion formed so as to face the tapered portion of the body inside the cylindrical portion of the nozzle is plastically deformed by abutting the tapered portion, and the nozzle is abutted by the tapered portion. And a contact portion that positions in a radial direction and an axial direction with respect to the fuel injection valve.