JPH0976771A - Resin-made fuel injection tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a resin-made fuel injecting tube itself from being damaged by providing a fragile part fractured by the concentration of stress generated by an impact load in a part other than an injecting tube. SOLUTION: In a resin-made fuel injecting tube which is composed of an injecting tube main body 1, a breather tube 2 and a plate-like connecting part 3 for connecting the injecting tube main body and the breather tube to each other and formed by a unified molding method, a fragile part 30 is provided in the connecting part 3. Since stress generated by an impact load is concentrated in the fragile part 30, the fragile part 30 is fractured and the impact load is absorbed, the injecting tube main body 1 is prevented from being damaged.

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 made of resin, and more particularly to a fuel injection pipe in which a main body of an injection pipe serving as a fuel passage and a breather pipe for bleeding air are integrally formed.

[0002]

2. Description of the Related Art A fuel injection pipe is used as a passage for connecting an injection port provided in a vehicle body of an automobile and a fuel tank to supply fuel to the fuel tank. Conventionally, the fuel injection pipe has been mainly made of metal. However, since it is made of metal, it is heavy and has a problem in workability in attaching and detaching it from the vehicle body.

Further, at the time of fuel injection, it is necessary to bleed out the air in the fuel tank in accordance with the fuel injection amount, and it is necessary to provide a breather tube in addition to the fuel injection tube. In the conventional metal fuel injection pipe, a separately formed metal breather pipe is arranged along the fuel injection pipe, but a means for fixing the fuel injection pipe and the breather pipe is required, Due to the large number of parts, the workability of mounting and dismounting has become more difficult.

Therefore, in recent years, it has been proposed that the fuel injection pipe and the breather pipe are made of resin, and they have been put into practical use as early as in the Western countries. By being made of resin, it becomes lighter,
In addition to improving workability of attachment and detachment, it is possible to integrally form the fuel pipe and the breather pipe, which has the effect of significantly reducing the number of parts and the number of attachment and detachment steps.

[0005]

However, the fact that the resin fuel injection pipe has a lower strength than the metal fuel injection pipe exists. Therefore, in order to prevent the damage at the time of a collision of a vehicle with the same strength as metal, various reinforcing materials are mixed or the wall thickness is increased. However, when the reinforcing material is mixed or the wall thickness is increased, not only the whole weight becomes large but also the volume becomes large, and the workability of attaching / detaching decreases and the advantage of being made of resin is halved. is there.

The fuel injection pipe made of resin is generally formed by a blow molding method. However, in blow molding, a recessed notch may be formed inside the pipe, and the presence of such a notch causes stress concentration and damage is likely to occur, so that there is a problem that the wall thickness must be further increased. The present invention has been made in view of the above circumstances, and by providing a fragile portion other than the injection pipe that breaks by concentrating the stress of an impact load at the time of a collision, damage to the resin fuel injection pipe itself is prevented. The purpose is to prevent it, and thus make it possible to reduce the wall thickness.

[0007]

The resin fuel injection pipe of the present invention for solving the above-mentioned problems is characterized by an injection pipe main body serving as a fuel passage, a breather pipe, and a plate connecting the injection pipe main body and the breather pipe. The fuel injection pipe is made of resin and is integrally molded with a connecting portion having a shape of a rectangular shape, and the connecting portion is provided with a fragile portion.

The resin fuel injection pipe of the second invention is characterized in that, in the resin fuel injection pipe of the first invention, the fragile portion is a groove or a thin wall portion, and the resin fuel injection pipe is simultaneously molded by pressing at the time of blow molding. At the time of blow molding, the excess thickness of the connecting portion is moved to at least the injection pipe side, and the inner peripheral portion of the injection pipe facing the fragile portion is made thick.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the resin fuel injection pipe of the present invention,
A fragile portion is provided in a plate-shaped connecting portion that connects the injection pipe body and the breather pipe. Therefore, when an impact load is applied to the fuel injection pipe at the time of a vehicle collision, stress concentrates on the fragile portion and breaks, which absorbs the impact load. Further, the fracture of the fragile portion facilitates the deformation of the connecting portion, and the bending of the fuel injection pipe allows the impact load to be dispersed throughout.

If the fragile portion is formed at the time of integral molding, the excess thickness can be transferred to the fuel injection pipe side.
Even when formed by blow molding, it is possible to prevent the notch from being formed inside the fuel injection pipe. Therefore, stress concentration is prevented, and high strength can be obtained even with a thin wall. By these actions, damage to the injection pipe body and the breather pipe is prevented, so that it is not necessary to excessively increase the strength, and a lightweight and inexpensive resin fuel injection pipe can be obtained.

The fragile portion can be provided by selecting from a slit, a groove, a thin portion, or the like. This fragile portion is preferably 1/3 or more of the total length of the fuel injection pipe. If it is less than 1/3 of the total length, it becomes difficult to absorb the impact load, and the effect of providing the fragile portion is hardly obtained. In the case of forming a groove, it is preferable that the stress is easily concentrated by forming a V-shaped cross section.

Further, basically, the positions where the fragile portions are provided are preferably distributed evenly over the entire length so that the injection pipe main body and the breather pipe can be divided. However, if there is a problem in the attachment / detachment work, or if there is a problem with the holding property or vibration, it should be installed over ± 100 mm or more so as to sandwich the part that is likely to be impacted or the part that is likely to interfere with the vehicle body. desirable.

As the resin material, high density polyethylene is preferable in the case of automobiles from the viewpoint of material strength, fuel oil resistance and cost. Further, in order to improve the impermeability of fuel vapor, a plurality of types of resins may be laminated in multiple layers. When the weak portion is a slit or a groove, it is preferable that the weak portion is integrally formed at the time of blow molding and is provided close to the injection pipe body. As a result, the extra thickness of the fragile portion moves to the injection pipe main body side, so that it is possible to prevent a notch from being formed inside the injection pipe main body.

[0014]

The present invention will be described below in detail with reference to examples. (Embodiment 1) FIG. 1 shows a front view of a main portion of a fuel injection pipe of this embodiment. This fuel injection pipe is used for automobiles and is composed of an injection pipe main body 1, a breather pipe 2, and a plate-like connecting portion 3 connecting the injection pipe main body 1 and the breather pipe 2, and is made of high density polyethylene (HDPE). Is integrally formed by blow molding.

The injection tube body 1 includes a filler neck portion 10
And a filler pipe 11, and a bracket 12 fixed to the vehicle body is formed on a part of the filler pipe 11. In the injection pipe body 1, a filler neck portion 10 is fixed to an injection port of a vehicle body via a retainer (not shown), and the other end of the filler pipe 11 is connected to a fuel tank via a rubber hose.

The breather pipe 2 extends along the injection pipe body 1 and has one end communicating with the filler neck 10 and the other end connected to the fuel tank via a rubber hose. The connecting portion 3 is
Fill the space between the injection pipe body 1 and the breather pipe 2 to about 3 m
It is a plate with a wall thickness of m. This connecting portion 3 has a structure shown in FIG.
As shown in an enlarged view of the AA cross section of FIG. 1, a V-shaped V-shaped cross section extending along the injection pipe body 1 and the breather pipe 2 is shown.
The groove 30 is formed. The V groove 30 has a width of about 5 mm, a depth of about 3 mm, and a break portion (bottom portion of the V groove 30) having a thickness of 0.1 to 0.3 mm at the center of the connecting portion 3 in the width direction. I am configuring. Further, the V groove 30 is continuously formed over 2/3 of the entire length of the fuel injection pipe. This V
By adjusting the width and depth of the groove 30 and the number thereof, the magnitude of the shock load absorbed can be set.

Therefore, in the fuel injection pipe of this embodiment, when an impact load is applied at the time of a collision, the stress is V-groove 3
The V-grooves 30 are fractured by focusing on 0. As a result, the impact load is absorbed and damage to the injection pipe body 1 and the breather pipe 2 is prevented. In addition, due to the breakage of the V groove 30, the injection pipe body 1
Also, the degree of freedom of deformation of the breather pipe 2 is increased, and the deformation also absorbs an impact load.

The V groove 30 may be provided at the time of blow molding, or may be formed by machining after molding. (Embodiment 2) Although the V groove 30 was formed in the above-mentioned Embodiment 1, instead of the V groove 30, as shown in FIG.
1 can also be provided. Also in this case, when an impact load is applied at the time of collision, the stress concentrates on the thin wall portion 31 and the thin wall portion 31 is deformed, and if a stronger impact load is applied, the thin wall portion 31 is torn, and in the case of the V groove 30. The same effect as is obtained.

The thin portion 31 may be provided during blow molding, or may be formed by machining after molding. Further, the thin portion 31 may be partially penetrated to form a slit, and the presence of a thin burr does not affect the effect of the present invention. Further, when the thin portion 31 is thin and there is a problem in terms of holding property and vibration, the injection pipe main body 1 and the breather pipe 2 may be partially connected by the bridge portion 32 as shown in FIG. it can.

Further, it is preferable to form the slit during blow molding, because the effect of preventing blow-molding pinch-off can be obtained. However, from the viewpoint of formability, it is preferable that the slit width is about 3 to 5 mm. If the slit width is too wide, it is necessary to increase the mold clamping force, which is not preferable. (Embodiment 3) By the way, the fuel injection pipe of the above embodiment is integrally formed by blow molding. When the plate-shaped part adjacent to the tubular body is formed by blow molding, the plate-shaped part is formed by sandwiching the parison with the mold so that the parison faces the inner surface of the tubular body opposite to the plate-shaped part. Usually, a groove-shaped notch is formed along the plate portion.

Embodiments 1 and 2 are no exception, and as shown in FIGS. 2 to 4, a groove extending along the connecting portion 3 is formed on the inner peripheral surface of the injection pipe body 1 on the opposite side of the connecting portion 3. Notch 13 is formed. When the notch 13 is formed on the inner peripheral surface of the injection pipe body 1 as described above, stress concentrates on that portion as well, and the stress to be concentrated on the V groove 30 or the thin portion 31 is dispersed.

Therefore, the fuel injection pipe of this embodiment has the same structure as that of the first embodiment except that the V groove 33 is formed in the vicinity of the injection pipe body 1 as shown in FIG. Therefore, at the time of blow molding of the fuel injection pipe of the present embodiment, the excess thickness of the V groove 33 is moved to the injection pipe body 1 side by the mold pressing to fill the notch 13 and the thick portion 34 is formed. That is, in the fuel injection pipe of the present embodiment, the notch is not formed on the inner peripheral surface of the injection pipe body 1 facing the V groove 33 and the thick portion 34 is formed on the contrary, so that V is applied when an impact load is applied.
The stress can be effectively concentrated in the groove 33.

Further, instead of the V groove 33, a thin portion 35 may be formed on the injection pipe body 1 side as shown in FIG. Also in this case, during blow molding, the excess thickness of the thin portion 35 moves to the injection pipe body 1 side to fill the notch 13 and the thick portion 34 is formed. In order to effectively transfer the excess thickness to the injection pipe body 1 or the breather pipe 2, the wall thickness of the connecting portion 3 is smaller than twice the wall thickness of the parison, preferably 1 wall thickness of the parison.
It is preferably set to / 2 or less. By doing so, the amount of excess thickness transferred increases, and the thick portion 34 can be easily formed.

It is also preferable to provide the V groove 33 and the thin portion 35 not only on the injection pipe body 1 side but also on the breather pipe 2 side. As a result, a thick portion is formed also on the breather pipe 2 side, so that the strength of the breather pipe 2 is improved and stress can be further concentrated on the fragile portion.

[0025]

In other words, according to the resin fuel injection pipe of the present invention, stress is concentrated on the fragile portion when an impact load is applied at the time of collision of the vehicle, and the stress is absorbed by the fragile portion being broken. . Therefore, stress is prevented from acting on the injection pipe body and the breather pipe, and damage to the injection pipe body and the breather pipe is prevented.

[Brief description of drawings]

FIG. 1 is a front view of a main part of a resin fuel injection pipe according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part including a cross section taken along the line AA of FIG.

FIG. 3 is a perspective view of a principal part corresponding to FIG. 2 of a resin fuel injection pipe according to a second embodiment of the present invention.

FIG. 4 is a perspective view of an essential part corresponding to FIG. 2, showing another embodiment of the resin fuel injection pipe of the second embodiment of the present invention.

FIG. 5 is a sectional view of a resin fuel injection pipe according to a third embodiment of the present invention.

FIG. 6 is a sectional view showing another embodiment of the resin fuel injection pipe of the third embodiment of the present invention.

[Explanation of symbols]

1: Injection tube body 2: Breather tube
3: Connection part 30: V groove (fragile part) 31: Thin part (fragile part)
32: Bridge part 33: V groove (fragile part) 34: Thick part
35: Thin portion (fragile portion)

Claims (2)

[Claims] 1. A resin-made fuel injection pipe integrally formed of an injection pipe main body serving as a fuel passage, a breather pipe, and a plate-like connecting portion connecting the injection pipe main body and the breather pipe. The resin fuel injection pipe is characterized in that the connecting portion is provided with a fragile portion. 2. The fragile portion is a groove or a thin-walled portion and is simultaneously molded by pressing at the time of blow molding, and at the time of the blow molding, the excess thickness of the connecting portion is moved to at least the injection pipe side and the fragile portion is formed. 2. The resin fuel injection pipe according to claim 1, wherein an inner peripheral portion of the injection pipe facing the fuel injection pipe has a thick wall.