JP2909713B2 - Fuel injection pipe for fuel tank and method of manufacturing the fuel injection pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection pipe for a fuel tank, and more particularly, to a fuel injection pipe having a fuel injection port for injecting fuel and mounting a cap at an opening of a pipe constituting the fuel injection pipe. And its manufacturing method.

[0002]

2. Description of the Related Art A fuel tank of an automobile is provided with a fuel injection pipe for injecting fuel, and an opening of the fuel injection pipe is provided, for example, as described in Japanese Utility Model Laid-Open Publication No. 63-130324. In order to removably attach the cap and guide the fueling nozzle, a pipe constituting a fuel inlet is joined. As described in the publication, a pipe constituting a fuel injection port is generally made of metal, and this is welded to a metal fuel injection pipe. Further, there is also known a fuel injection device in which a cover made of a metal or resin cylinder is provided on the outer periphery of a fuel inlet. As the cover, a cover is known which is divided into two parts in the axial direction and joined so as to sandwich the fuel injection port, and then welded at the joint part in the axial direction. Alternatively, a fuel injection port formed of a resin material has been proposed as described in Japanese Patent Application Laid-Open No. 6-144026.

FIG. 8 shows an example of a conventional fuel injection pipe. One end of a fuel injection pipe 2x is connected to a fuel tank (not shown), and the other end is connected to a fuel filler port (shown by a two-dot chain line) of a vehicle. Is established. Then, fuel is injected from the opening of the fuel injection pipe 2x, and when the cap 6x is attached to the fuel injection pipe 2x, the fuel injection pipe 2x is sealed. The inside of the opening of the fuel injection pipe 2x is welded to a pipe 4x constituting a fuel injection port, and the outside is fitted with a cover 7x.

[0004]

However, in the case where the metal fuel injection pipe is welded to the fuel injection pipe, the metal fuel injection pipe is composed of two parts and has a large number of welds, so that the production is not easy and the cost is high. It has become. On the other hand, if the fuel injection port is made of a resin material as described in Japanese Patent Application Laid-Open No. 6-144026, the weight and cost can be reduced. It is not that a significant cost down can be expected only for the inlet.

Accordingly, an object of the present invention is to provide a fuel injection pipe for a fuel tank, in which a fuel injection port is integrally formed at an opening of a pipe constituting the fuel injection pipe, thereby further reducing the cost. I do.

Further, the present invention provides a method of manufacturing a fuel injection pipe for a fuel tank, wherein a fuel injection port having a double pipe structure is formed easily and reliably at an opening of the pipe body without joining another member. Another purpose is to gain.

[0007]

In order to achieve the above object, the present invention provides a fuel injection pipe for a fuel tank having a fuel injection port for injecting fuel and mounting a cap at an opening of a pipe body. At the fuel inlet, an opening of the tube is bent toward the body of the tube to form a superposed portion that is superimposed and closely adhered , and inner and outer members constituting the superposed portion. > At least one screw portion to be screwed with the cap is formed.

Further, the present invention provides a method of manufacturing a fuel injection pipe, which comprises expanding an area near one opening to a metal pipe to form an expanded section, and extending the pipe from the expanded section toward an opening end. The one opening is reduced in diameter so that the diameter gradually decreases to form a first tapered portion, and the first tapered portion is connected to the first tapered portion.
A pipe expanding step of forming a second tapered portion in which the pipe diameter gradually decreases in the direction of the opening end at a rate different from the gradually decreasing rate of the pipe diameter of the tapered portion, and the first tapered portion and the second tapered portion are formed by A bending step of bending toward the expanded portion, forming a overlapped portion in which the first and second tapered portions and the expanded portion overlap, into a predetermined shape, and at least one threaded portion in the overlapped portion. And a forming step of forming

Further, as a method of manufacturing a fuel injection pipe according to the present invention, a pipe section is formed by expanding the vicinity of one opening with respect to a metal pipe body, and the pipe is formed from the pipe expanding section toward the opening end. The one opening is reduced in diameter so that the diameter gradually decreases, and
And a second tapered portion having a diameter gradually decreasing toward the opening end at a rate different from the decreasing rate of the diameter of the first tapered part continuously from the first tapered part. A pipe-expanding step of forming a reduced-diameter portion having a constant diameter and extending in the direction of the opening end continuously with the second tapered portion; a cutting step of cutting the reduced-diameter portion; Tapered portion and the second
A bending step of bending the tapered portion toward the expanded tube portion side, and forming an overlapped portion in which the first and second tapered portions and the expanded tube portion overlap, and expanding an end portion of the overlapped portion. The present invention may be configured to include a superposed portion forming step of forming a seal portion whose pipe diameter increases in the direction of the opening end, and a screw forming step of forming at least one thread portion in the superposed portion.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As an embodiment of a fuel injection pipe having the above-described configuration, for example, a fuel injection pipe 1 shown in FIG. 1 is configured. This is a metal tube having a fuel inlet 3 formed at an opening at one end and a fuel tank (not shown) at the other end. A cap (not shown) is screwed into the fuel inlet 3. Fuel inlet 3
The opening of the pipe constituting the fuel injection pipe 1 is bent toward the main body 2 to form a superimposed section 4 which is superimposed and adhered to the main body 2, and the end of the superposed section 4 is outward. The inner portion and the outer portion forming the overlapping portion 4 are formed by expanding the seal portion 4a.
The material has at least one threaded portion 4b. In FIG. 1, the main body 2 is provided with a tube expanding portion 2a and a locking portion 2f formed on a base tube portion 2p via a connecting portion 2e, which will be described later. The fuel injection pipe 1
Is connected to a fuel tank (not shown). Thus, when a cap (not shown) is screwed into the fuel injection port 3, the fuel injection pipe 1 is sealed. Moreover, the overlapping portion 4 is formed in the fuel injection port 3 and has a double pipe structure in which the fuel injection port 3 is in close contact with the fuel injection port 3. Therefore, sufficient strength is ensured and, for example, appropriate protection against external impact is provided.

The fuel injection pipe 1 having the above structure can be manufactured by various methods. One of the forms is as shown in FIG. The vicinity is expanded to form an expanded portion 2a, and one opening is reduced in diameter so that the diameter of the tube gradually decreases toward the opening end of the one opening to form a first tapered portion 2b. 1
A pipe expanding step B in which a second tapered portion 2c whose diameter gradually decreases in the opening end direction at a rate different from the gradually decreasing rate of the diameter of the first tapered part 2b following the tapered part 2b of the first step; A bending process D for bending the tapered portion 2b and the second tapered portion 2c toward the expanded tube portion 2a, and the first and second tapered portions 2b and 2c.
The overlapping portion 4 formed by superimposing the tube portion 2a is formed into a predetermined shape (for example, a shape in which a seal portion 4a described later is formed at an end portion), and at least one screw portion 4 is formed on the overlapping portion 4.
There is a manufacturing method comprising a molding step E for forming b.
In FIG. 2, the reduced diameter portion 2d is formed, and the cutting step C is performed.
And the like, which will be described later.

[0012]

Next, specific examples of the manufacturing method in the above embodiment and examples of the fuel injection pipe 1 manufactured by the method will be described with reference to the drawings. FIG. 2 shows one embodiment of a method of manufacturing the fuel injection pipe 1 shown in FIG.
B, C, D, E1, and E2. First, a metal pipe Bp is disposed (A), and in a pipe expansion step B, the pipe Bp is expanded by, for example, bulge forming. That is, as shown in FIG. 3, the vicinity of one opening of the raw tube Bp is expanded to form a tube expanding portion 2a, and the opening is reduced in diameter so that the tube diameter gradually decreases in the direction of the opening end. Tapered part 2b
Is formed, and the pipe diameter gradually decreases toward the opening end at a rate (taper angle Tb in FIG. 3) smaller than the rate of decrease in the diameter of the first taper portion 2b (taper angle Ta in FIG. 3). A tapered portion 2c is formed. The second tapered portion 2c is formed longer than the first tapered portion 2b. In addition, in the present embodiment, a reduced diameter portion 2d having a constant pipe diameter is formed to extend in the opening end direction continuously from the second tapered portion 2c, but the reduced diameter portion 2d is not necessarily required to be formed. . At the other open end side (lower side in FIG. 1) of the raw tube Bp, a connecting portion 2e is formed, which is continuous with the expanded tube portion 2a and whose diameter gradually decreases to reach the raw tube portion 2p.

Next, after the reduced diameter portion 2d is cut in the cutting step C shown in parentheses in FIG. 2, the process proceeds to the bending step D. still,
When the reduced diameter portion 2d is not formed in the pipe expanding step B, the cutting step C is omitted. In the bending process D, as shown by arrows in FIGS. 2 and 3, when an axial pressing force P is applied to the opening end face of the second tapered portion 2c, the first tapered portion 2b and the second The second tapered portion 2c is folded inside the expanded tube portion 2a as shown by a broken line. At this time, due to the presence of the first tapered portion 2b and the second tapered portion 2c, the bending operation is performed smoothly without applying a large load to the bent portion.

FIG. 4 shows a comparative example in which a reduced diameter portion 2g having a constant pipe diameter is formed without providing the second tapered portion 2c. In this comparative example, the diameter of the opening of the reduced diameter portion 2g is increased. When the pressing force P is applied, the connecting portion is deformed as shown by a broken line in FIG. 4 and is connected to the connecting portion between the first tapered portion 2b and the reduced diameter portion 2g and the connecting portion between the first tapered portion 2b and the expanded tube portion 2a. Since an excessive load is applied, it is necessary to carefully perform bending work while preventing damage. In contrast, in the present embodiment,
Since the second tapered portion 2c is formed, when the second tapered portion 2c is pressed and moves downward in FIG. 3, it is divided in the direction in which the tube is expanded with respect to the expanded portion 2a (the left-right direction in FIG. 3). Forces arise. For this reason, while the pressing force P is appropriately distributed to the expanded tube portion 2a, the first and second tapered portions 2b and 2c are connected to the expanded tube portion 2a.
It is properly folded inside a.

Then, the process proceeds to the overlapping portion forming step E1, in which the end of the overlapping portion 4 is expanded and formed so that the pipe diameter increases in the direction of the opening end, and the sealing portion 4a shown in FIG. It is formed. 1 is formed in the screw forming step E2, and a substantially single groove-shaped screw portion 4b is formed in the overlapping portion 4 of the fuel injection pipe 1. The screw portion 4b is not limited to a single groove, but may have two or more grooves .
When viewed from the outside, it may be a ridge instead of a groove. At this time, a locking portion 2f of an annular projection protruding to the outer peripheral side of the expanded portion 2a is also formed. The overlapping portion forming step E1 may be incorporated into the screw forming step E2 and may be performed simultaneously as the forming step E.

Thus, the overlapping portion 4 of the fuel injection pipe 1 has a double pipe structure, and is appropriately protected against external impact. Then, when the cap (not shown) is screwed into the overlapping portion 4 as in FIG. 8, the annular seal (not shown) of the cap comes into close contact with the seal portion 4a, and the fuel injection pipe 1 is sealed. Note that a resin cylindrical cover 7x as shown in FIG. 8 may be provided around the locking portion 2f of the fuel injection pipe 1.

FIG. 6 shows another embodiment of the fuel injection pipe 1 according to the present invention, in which the overlapping portion 4 is formed to be bent inward at a position separated from the opening end of the main body portion 2 and a fueling nozzle (see FIG. 6). (Not shown) is formed. In addition, the overlapping portion 4 can be formed in a desired shape.

FIG. 7 shows still another embodiment of the fuel injection pipe 1. Contrary to the above-described embodiment, the first tapered portion 2b and the second tapered portion 2c correspond to the expanded tube portion 2a. Parts that are bent outward and are substantially the same as those in FIGS. 1 and 6 are denoted by the same reference numerals. When the fuel injection pipe 1 of FIG. 7 is manufactured, naturally, unlike FIG. 3, the first tapered portion 2b and the second tapered portion 2c are expanded so as to bulge outside the expanded portion 2a. There is a need. Thus, through the bending step and the forming step, the second tapered portion 2c becomes
This is the portion indicated by c.

[0019]

Since the present invention is configured as described above, the following effects can be obtained. That is, according to the fuel injection pipe for a fuel tank of the present invention, the opening of the pipe body is provided at the fuel injection port.
The part is bent to the main body part side to form a superposed part which is superimposed and adhered, and the screw part is formed in this superposed part, so that it can be manufactured easily and inexpensively. Nevertheless, the fuel inlet can be appropriately protected against external impact.

Further, according to the method of manufacturing a fuel injection pipe of the present invention, an expanded portion is formed by expanding the vicinity of one opening in a metal pipe, and the pipe is formed in the direction from the expanded portion to the opening end. One of the openings is reduced in diameter so that the diameter gradually decreases to form a first taper portion, and the second taper is continuous with the first taper portion and gradually decreases in diameter toward the opening end at a rate different from the rate of decrease in the diameter of the pipe. Is formed, the first tapered portion and the second tapered portion are bent toward the expanded portion, and an overlapped portion formed by overlapping these portions with the expanded portion is formed into a predetermined shape. Since both are to form a single thread, from a single tube,
A fuel injection pipe having a fuel injection port having a double pipe structure can be easily and inexpensively manufactured.

[Brief description of the drawings]

FIG. 1 is a partially sectional front view of a fuel injection pipe according to one embodiment of the present invention.

FIG. 2 is a process diagram showing a manufacturing process of a fuel injection pipe according to one embodiment of the present invention.

FIG. 3 is a cross-sectional view of an intermediate product formed at the time of manufacturing a fuel injection pipe according to one embodiment of the present invention.

FIG. 4 is a sectional view showing a comparative example with respect to an intermediate product formed at the time of manufacturing the fuel injection pipe according to one embodiment of the present invention.

FIG. 5 is an enlarged sectional view of a seal portion formed at a fuel injection port of a fuel injection pipe according to one embodiment of the present invention.

FIG. 6 is a partially sectional front view showing a fuel injection port of a fuel injection pipe according to another embodiment of the present invention.

FIG. 7 is a partially sectional front view showing a fuel inlet of a fuel injection pipe according to still another embodiment of the present invention.

FIG. 8 is a partial cross-sectional front view showing a state in which a cap is attached to a conventional fuel injection pipe.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 fuel injection pipe 2 main body part 2a expanded pipe part 2b first tapered part 2c second tapered part 2d reduced diameter part 2e connecting part 2f locking part 2g reduced diameter part 2p raw pipe part 3 fuel injection port 4 overlapping part 4a seal Part 4b Screw part Bp pipe

Claims (3)

(57) [Claims] 1. A fuel injection pipe for a fuel tank having a fuel injection port for injecting fuel and attaching a cap to an opening of the pipe, wherein the opening of the pipe is connected to the pipe at the fuel injection port. At least one threaded portion that is screwed with the cap is formed on the inner and outer members constituting the overlapped portion while being bent and polymerized to form a tightly adhered overlapped portion on the body portion side. A fuel injection pipe for a fuel tank, wherein the fuel injection pipe is formed. 2. An expanded portion is formed by expanding the vicinity of one of the openings in the metal tube, and the one of the openings is gradually reduced from the expanded portion toward the opening end. The first tapered portion is formed by reducing the diameter, and the pipe diameter is gradually reduced in the direction toward the opening end at a rate different from the gradually reduced rate of the pipe diameter of the first tapered section following the first tapered section. A step of forming a second tapered portion; a step of bending the first tapered portion and the second tapered portion toward the expanded tube;
And the overlapping portion where the second tapered portion and the expanded portion overlap,
Forming a predetermined shape and forming at least one threaded portion in the overlapping portion. 3. A metal pipe body is expanded near the one opening to form an expanded part, and the one opening is gradually reduced from the expanded part toward the opening end. The first tapered portion is formed by reducing the diameter, and the pipe diameter is gradually reduced in the direction toward the opening end at a rate different from the gradually reduced rate of the pipe diameter of the first tapered section following the first tapered section. A step of forming a tapered portion having a constant diameter and forming a second tapered portion and extending in the direction of the opening end continuously to the second tapered portion; and a cutting step of cutting the reduced diameter portion. And a bending step of bending the first tapered portion and the second tapered portion toward the expanded portion, and forming a superposed portion in which the first and second tapered portions and the expanded portion overlap. Along with, expanding the end of the polymerization section,
A method for manufacturing a fuel injection pipe, comprising: a forming step of forming a sealing portion having a pipe diameter increasing toward the opening end; and a screw forming step of forming at least one screw portion in the overlapping portion.