JP2004124903A - Tube connection port of fuel tank - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a tube connection port of a fuel tank so as to simultaneously materialize high barrier performance and thermal welding performance to the tank, without complicating a structure. <P>SOLUTION: In the tube connection port 1 the fuel tank comprises a joint element 2 equipped with a tube connecting portion 4 shaped in a cylinder projecting to the outside of a synthetic resinous fuel tank T, and a flange 5 joined with an outer surface of the fuel tank; and an extension pipe 7 united to the joint element at one end. The extension pipe has outside diameter dimensions comparatively closely fitted with an inner peripheral surface of the tube connecting portion, and is formed with a diameter expanding portion abutting on an axial direction outer end of the tube connecting portion at one end 7a. The joint element is formed by thermal welding material, and the flange of the joint element assembled with the extension pipe is thermally welded to the fuel tank. Therefore, uniting between the extension pipe and the joint element is held by fitting the tube. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tube connection port particularly adapted to a fuel tank made of synthetic resin.
[0002]
[Prior art]
Since rust prevention and weight reduction are easy and high productivity can be obtained, there is an increasing tendency to use a tank formed by blow molding a synthetic resin material as a fuel tank for automobiles.
[0003]
On the other hand, at the outlet of the fuel injection pipe connected to the filler tube into the fuel tank, a check valve is provided to prevent the injected fuel from flowing back, but the fuel tank is formed of a synthetic resin material. In this case, from the viewpoint of simplifying the manufacturing process, it is preferable that the check valve can be connected to the fuel tank by heat welding.
[0004]
From such a viewpoint, the fuel tank includes a tank outer portion serving as a joint body coupled to the fuel tank and a tank inner portion serving as a check valve holding member that holds the check valve, which are separately provided. The welding piece that is a welded part with the filler tube, the connection part with the filler tube, and the leg wall that is the connection part with the check valve holder are integrally formed with the joint body, and this is welded to the outer surface of the fuel tank. The structure is disclosed in JP-A-11-78549.
[0005]
[Patent Document 1]
JP-A-11-78549 (FIGS. 1 to 5)
[0006]
[Problems to be solved by the invention]
However, high-density polyethylene (hereinafter, referred to as HDPE) that can be thermally welded is relatively poor in permeability (hereinafter, referred to as barrier property) of hydrocarbons (hereinafter, referred to as HC). From the viewpoint of preventing radiation, it is not suitable for use as an accessory for gasoline tanks.
[0007]
In order to suppress the permeation of HC, it is preferable to use a material having a high barrier property such as an ethylene vinyl alcohol copolymer (hereinafter referred to as EVOH). However, such a so-called gasoline barrier material has an adhesive property due to thermal welding. If the joint body is made of a gasoline barrier material, it is difficult to satisfy the bonding strength with a fuel tank if the joint body is made of a gasoline barrier material.
[0008]
It is conceivable that only the joint body is formed of a heat-sealable material and the check valve holder is formed of a gasoline barrier material. However, according to the structure described in the above document, the joint between the joint body and the check valve holder is considered. In addition, the structure of the portion tends to be complicated, and it is impossible to prevent HC permeation from a part of the joint body directly exposed to the HC atmosphere in the fuel tank, and it is not possible to secure a sufficiently satisfactory barrier property.
[0009]
The present invention has been devised to solve such problems of the prior art, and a first object of the present invention is to provide an improved fuel tank tube connection port so as to further simplify the structure. To provide. Further, a second object of the present invention is to achieve all of high strength and rigidity, gasoline swelling resistance, high barrier property, and heat welding property to a fuel tank at a high level without complicating the structure. Therefore, an object of the present invention is to provide an improved tube connection port.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, according to claim 1 of the present invention, a joint having a cylindrical tube connecting portion 4 protruding outward from the fuel tank T and a flange 5 joined to the outer surface of the fuel tank is provided. At the tube connection port 1 of the fuel tank having a body 2 and an extension pipe 7 having one end connected to a joint body, an outer diameter for fitting the extension pipe relatively tightly to the inner peripheral surface of the tube connection portion. The enlarged diameter portion which is dimensioned and abuts on the axially outer end of the tube connecting portion is formed at one end 7a thereof, and the joint body is formed of a heat-sealable material, and the extension pipe is assembled. The flange of the joint body was thermally welded to the fuel tank.
[0011]
With this configuration, the connection between the extension pipe and the joint body is maintained by fitting the tube, so that the structure of the connection portion between the two can be simplified.
[0012]
In particular, if a barrier material layer (EVOH layer 6) is provided on the surface of the joint body facing the inside of the fuel tank and the fitting surface of the extension pipe (claim 2), the portion using the gasoline barrier material can be reduced. High barrier properties can be ensured after minimization.
[0013]
In addition, if the barrier material is exposed to the fitting surface of the tube (claim 3), it is possible to improve the ability to prevent HC from seeping out from the fitting surface between the joint body and the tube.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
[0015]
FIG. 1 shows a cross section of a filler tube connection port with a check valve constructed according to the present invention cut along an axis. The filler tube connection port 1 with a check valve comprises a joint body 2 connected to a fuel tank T formed by blow molding of a synthetic resin material, and a check valve holding body 3 for holding the check valve. I have.
[0016]
The joint body 2 has a cylindrical filler tube connecting portion 4 formed at a portion protruding outward from the fuel tank T, and a flange 5 formed at one end thereof to be joined to an outer surface of the fuel tank T. . Most of the filler tube connecting portion 4 and the flange 5 are formed of HDPE (roughly hatched portion), and the inner peripheral surface of the filler tube connecting portion 4 and a large surface of the flange 5 facing the inside of the fuel tank. The part is covered with the EVOH layer 6 (the part with fine hatching). The joint body 2 is joined to the fuel tank T by heat-welding the axial end face on the outer peripheral side of the flange 5 to the outer surface of the fuel tank T. The joint body 2 can be formed by, for example, a two-color molding method in which a primary molded portion made of HDPE is inserted to form a secondary molded portion made of EVOH.
[0017]
The check valve holder 3 includes an extension pipe 7, a valve housing 8, and a valve guide 9, and has a valve body 10 built in the valve housing 8.
[0018]
The extension pipe 7 has an outer diameter dimension that fits relatively tightly with the inner peripheral surface (EVOH layer 6) of the filler tube connection portion 4 of the joint body 2 and has one end 7a that is expanded in diameter to connect the filler tube. It is configured to abut the axially outer end of the part 4. When the extension pipe 7 is press-fitted into the inner periphery of the EVOH layer 6 in the filler tube connecting portion 4, the one end 7 a is continuously connected to the outer peripheral surface of the filler tube connecting portion 4 and has a sawtooth-shaped cross section along the axis. It is tapered so as to form the tip of the mouth. A concave portion 12 is formed on the outer peripheral surface on the other end side to engage with a resilient claw 11 provided on the valve housing 8, and an axial end surface thereof is a valve seat 13 with which the valve comes into contact. In addition, a sufficiently high connection strength and liquid tightness can be obtained by press-fitting the extension pipe 7 into the joint body 2 and connecting them together.
[0019]
The valve housing 8 has a relatively short cylindrical shape, one end 8a of which is reduced in diameter to form a fitting portion with the other end of the extension pipe 7, and the other end 8b forms a fitting portion of the valve guide 9. ing.
[0020]
The valve guide 9 has a rim 9a fitted to the inner peripheral surface on the other end 8b side of the valve housing 8 and engaged with the other end 8b of the valve housing 8 with a resilient claw 14, and a rim 9a through a plurality of spokes 9b. The hub 9c includes a hub 9c supported at the center of the hub 9a and a guide cylinder 9d provided at the center of the hub 9c.
[0021]
The valve body 10 includes a rod 10a that slides on the guide cylinder 9d, and a valve 10b fixed to one end of the rod 10a. The valve 10 is connected to the valve seat 13 by a compression coil spring 15 contracted between the rod 9a and the hub 9c. Is normally biased in the direction of pressing, and is normally pressed by the valve seat 13 by the resilient force of the compression coil spring 15 to cut off communication between the inside and outside of the fuel tank, and when gasoline flows in, is displaced by the pressure. Gasoline is introduced into the fuel tank.
[0022]
Each member constituting the check valve holder 3 is formed of, for example, a polyacetal resin material having a high swelling resistance to gasoline. The filler tube connection port 1 with a check valve is inserted into the filler tube connection portion 4 by first press-fitting the extension pipe 7, and then the valve housing 8 in which the valve guide 9, the valve body 10 and the compression coil spring 15 are incorporated. Is fitted to the other end of the extension pipe 7 to be integrated.
[0023]
As shown in FIG. 4, the filler tube connection port 1 with a check valve having the above configuration is inserted into the fuel tank T from the hole 16 previously opened in the fuel tank T with the valve housing 8 side first, and The flange 5 is thermally welded to the outer surface of the fuel tank T to be integrally connected to the fuel tank T. The fuel tank T is extended through a filler tube H made of a flexible material connected to a filler tube connecting portion 4 protruding outward from the fuel tank T to a fuel filler opening opening outside the vehicle body.
[0024]
Here, as described above, since the EVOH layer 6 is formed on the surface of the flange 5 facing the inside of the fuel tank T and the fitting surface of the extension pipe 7 as described above, the permeation of HC is greatly suppressed. .
[0025]
When the filler tube H is fitted to the joint body 2 from the axially outer end side, the outward movement of the extension pipe 7 is prevented by the filler tube H. Therefore, the structure of the joint between the joint body 2 and the extension pipe 7 Is easy. By mounting the O-ring 18 around the convex portion 17 at the outer end of the joint body 2, even when gasoline seeps out from the gap between the EVOH layer 6 and the extension pipe 7, the outside of the filler tube H Gasoline is prevented from oozing out.
[0026]
FIG. 2 shows another embodiment of the present invention. In this embodiment, the EVOH layer 6 attached to the inner peripheral surface of the joint body 2 is enlarged in diameter at the outer end in the axial direction of the joint body 2 and is exposed to the fitting surface of the filler tube H so that one of the hose ports is exposed. A part of the filler tube H is directly fitted to the outer peripheral surface of the outer end 6 a of the EVOH layer 6. Thus, the O-ring 18 in the above configuration can be omitted.
[0027]
The present invention provides not only the above-described filler tube connection port, but also, for example, a connection port of a breather tube for communicating the inside of the fuel tank above an insertion port of the fuel gun, a pipe connection port to the fuel evaporative gas emission suppression device, and the like. Also, the present invention can be applied to connection ports of various accessory parts connected to the fuel tank. Also in this case, as shown in FIG. 3, the joint body 2 having an appropriate diameter, which is composed of the tube connecting portion 4 and the flange 5 and is covered with the EVOH layer 6, is connected to the axial end face on the outer peripheral side of the flange 5. Is heat-welded to the outer surface of the fuel tank T so as to be integrally connected to the fuel tank T, and a tube H formed of a flexible synthetic resin material is fitted to the joint body 2 from the axially outer end side. The outward movement of the extension pipe 7 inserted therein is prevented by the tube H, and the gasoline is prevented from seeping out of the tube H as in the above-described embodiment. .
[0028]
【The invention's effect】
As described above in detail, according to the present invention, the connection between the extension pipe and the joint body is maintained by fitting the flexible tube outside the fuel tank. This eliminates the need for the engaging means between the joint body and the extension pipe. Therefore, a great effect can be obtained in simplifying the structure of the joint between the joint body and the extension pipe. Further, in the prior art, in order to enhance the barrier property, it was necessary to dispose a wide range of gasoline barrier materials including sealing of the joint between the joint body and the extension pipe. Only gasoline barrier materials are required. Therefore, a great effect can be obtained in reducing the manufacturing cost by reducing the range of use of the expensive gasoline barrier material.
[0029]
In addition, since the joint body and the extension pipe are separately assembled and assembled together, the joint body must be used in common even when the position where the extension pipe enters the fuel tank differs depending on the connected device or vehicle type. It is also effective in reducing the number of parts.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of the filler tube connection port with a check valve according to the present invention along the axis. FIG. 2 is a cross-sectional view of a main part showing another embodiment of the filler tube connection port with a check valve according to the present invention. FIG. 4 is a sectional view of a main part showing still another embodiment of the present invention. FIG. 4 is a sectional view of a joint portion of a filler tube connection port with a check valve and a fuel tank according to the present invention.
DESCRIPTION OF SYMBOLS 1 Filler tube connection port with check valve 2 Joint body 3 Check valve holder 4 Filler tube connection part 5 Flange 6 EVOH layer 7 Extension pipe 8 Valve housing 9 Valve guide 10 Valve body 11 Resilient claws 12 Recess 13 Valve seat 14 Spring nail 15 Compression coil spring 16 Hole 17 Convex part 18 O-ring

Claims (3)

A joint body having a cylindrical tube connecting portion protruding outward from a synthetic resin fuel tank and a flange joined to an outer surface of the fuel tank, and an extension pipe having one end coupled to the joint body. A tube connection port of a fuel tank having
The extension pipe has an outer diameter dimension that fits relatively tightly with the inner peripheral surface of the tube connection part, and an enlarged diameter part that abuts an axially outer end of the tube connection part is formed at one end thereof. ,
The joint body is formed of a heat-sealable material,
The tube connection port of a fuel tank, wherein the flange of the joint body with the extension pipe assembled is heat-welded to the fuel tank. The fuel tank according to claim 1, wherein a layer made of a material that is hardly permeable to hydrocarbons is provided on a surface of the joint body facing the inside of the fuel tank and a fitting surface with the extension pipe. Tube connection port. The tube connection port for a fuel tank according to claim 1 or 2, wherein a portion of the hydrocarbon-impermeable material is exposed on a fitting surface of the tube.

Images