JPH0422149Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention is a hard tube (hard tube made of metal or hard resin material) among tubes for passing fluids such as water (liquid) and air. In addition to this, it also includes hard pipes made of inorganic materials and wood (the same applies hereinafter) and resin pipes (including airtight ones; the same applies hereinafter) connection structure. It is.

(b) Conventional technology It is relatively easy to connect metal pipes in a watertight manner. However, hard tubes and different materials,
In particular, it is difficult to connect resin pipes in a watertight manner, partly because resin pipes have poor strength and elasticity.

For example, in a car, pipes must be connected between the fuel tank and filler port, but vibration occurs between the two, and the position of the pipe may change slightly. Tubes cannot be connected together. For this reason, both tubes were partially made of rubber. This is because rubber tubes are highly elastic and have good vibration absorption properties as described above, and can be easily connected to hard tubes in a watertight manner by tightening them with a band or the like.

(c) Problems that the invention aims to solve However, the disadvantage of rubber tubes is that they are soft and easily scratched. Therefore, if a large impact occurs due to a collision or the like, the sharp points of other nearby members will hit and break, causing the fluid inside to leak out.

In this respect, resin has high mechanical strength (hardness) and a certain degree of elasticity, so it is suitable as a substitute for rubber, but it does not have enough elasticity to make the simple connection structure described above watertight, and in this respect, it is difficult to use. I was getting used to it.

(d) Means for solving the problem This invention solves this problem by connecting the hard pipe and the resin pipe with the following configuration.

That is, in a watertight connection structure between a hard pipe and a resin pipe, an inner flange is formed at the end of the hard pipe, and an elastic packing whose inner circumference is continuous is sandwiched between the inside and outside of this inner flange. Blow mold to form an outer flange part with an inverted V-shaped cross section that protrudes outward slightly from the end, and then attach the inner flange part formed at the end of the nut to the outer flange part of the resin pipe. Tighten until the outer periphery of the end of the resin tube is tightly fitted to the inner periphery of the elastic packing, and the outer flange of the resin tube is crimped and presses the elastic packing. and the resin pipe.

(e) Effect As a result, the hard pipe and the resin pipe are connected by flange connection and mutual fitting, but the flange connection is by the elastic packing sandwiched between the respective flanges, and the mutual fitting is by connecting the outer periphery of the resin pipe. By being tightly fitted to the inner periphery of the elastic packing, a watertight connection is ensured.

(f) Example Hereinafter, the case where the example of this invention is applied to the fuel tank of an automobile will be explained with reference to the drawings. The figure is an enlarged cross-sectional view of the main part after tightening, and FIG. 3 is an enlarged side view of a partial cross-section of the elastic packing.

In the case of an automobile fuel tank, a hard tube 2 made of metal or the like protrudes from the tank 1 side, so a resin tube 3 (to ensure flexibility) is connected to the other end of the hard tube 2 to the filler neck side. Therefore, one end (a bellows portion 3a is provided in the middle) is connected.

Therefore, regarding the connection structure, first, the hard tube 2,
Both resin pipes 3 have flange portions 4 and 5 formed at their ends, respectively. That is, the hard tube 2 has its end bent inward to form an inner flange portion (hereinafter referred to as flange portion) 4, and the resin tube 3 has a cross section that protrudes outward at a point slightly in the middle of the end. An inverted V-shaped outer flange portion (hereinafter referred to as flange portion) 5 is formed. Next, an elastic packing 6 made of rubber or the like having a continuous inner circumference is attached to the inside and outside of the flange portion 4 of the hard tube 2.
, and using nuts 7, tighten both flange parts 4 and 5.
Fasten so that they are joined. That is, an inner flange portion is formed at the end of the nut 7, and this inner flange portion is applied to the flange portion 5 of the resin tube 3 and tightened into a threaded portion formed on the outer periphery of the hard tube 2. As the nut 7 is tightened, the flange part 5 of the resin pipe 3 gradually narrows its V-shaped width, and is finally crimped, and the elastic packing 6 is formed with the flange part 4 of the hard pipe 2.
You will be unable to tighten it any further by pressing hard, but this is the normal fastening state. At the same time, resin pipe 3
The outer periphery of the end portion of is fitted into the inner periphery of the elastic packing 6. At this time, since the fitting between the two is set tightly, the resin pipe 3 is tightly fitted into the elastic packing 6.
At this time, seal protrusions 8 are provided on both sides where the elastic packing 6 contacts both the flange parts 4 and 5,
This seal protrusion 8
If it is crushed, the watertightness will be further improved.
Incidentally, such a resin pipe 3 can be easily manufactured by blow molding to obtain a relatively thin and uniform thickness.
By doing this, the flange portion 5 of the resin pipe 3 has a structure in which its thickness is elastically reduced by tightening the nut 7, which makes the tightening force stronger and prevents the contact between the elastic packing 6 and the resin pipe 3. The length can be made longer and the installation is more stable. Furthermore, even if the elastic packing 6 is used in a clamping structure, if a groove 6a is cut in the outer periphery and the flange part 4 of the hard tube 2 is inserted into this part so as to elastically abut both the circumferential surface and the side surface (the third (see figure), higher watertightness can be expected.

The above example is about the connection structure of a hose in an automobile fuel tank, but it is also applicable to a wide range of watertight connection structures for fluid distribution pipes other than automobiles, not to mention radiator hoses and air hoses. Of course, it can also be applied.

(g) Effects of the invention As described above, this invention has made it possible to connect a hard pipe and a resin pipe, which was quite difficult in the past. In this case, the connections were achieved by both flange connection via elastic packing and mutual fitting (circumferential connection), so sufficient watertightness could be ensured.

[Brief explanation of the drawing]

The drawings show the case where this invention is applied to a fuel tank of an automobile, and Fig. 1 is a partially sectional side view of the connection structure according to this invention, Fig. 2 is an enlarged sectional view of the main part after tightening, and Fig. 3 is an enlarged side view of a partial cross section of the elastic packing. Symbols, 2...Hard pipe, 3...Resin pipe, 4...Inner flange portion of hard tube, 5...Outer flange portion of resin pipe, 6...Elastic packing, 7...Nut.

Claims (1)

[Claims for Utility Model Registration] 1. In a watertight connection structure between a hard pipe and a resin pipe,
An inner flange is formed at the end of the hard tube, and an elastic packing with a continuous inner circumference is sandwiched between the inside and outside of this inner flange, while a resin tube is blow-molded and an inner flange is formed slightly inward from the end. The inner flange formed at the end of the nut is applied to the outer flange of the resin pipe and screwed into the hard pipe, and the end of the resin pipe The outer periphery is tightly fitted to the inner periphery of the elastic packing, and the outer flange of the resin pipe is crimped, and the elastic packing is tightened until the elastic packing is pressed. Watertight connection structure. 2. Request for registration of a utility model in which a sealing ridge is formed on the side surface of an elastic packing that contacts the inner flange of a hard pipe and the outer flange of a resin pipe, and the sealing ridge is crushed when a nut is tightened. A watertight connection structure between a hard pipe and a resin pipe according to item 1).