JP2003148678A - Pipe connecting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe connecting structure which prevents the peripheral surface of a steel pipe from being exposed to outside by certainly covering the periphery of the steel pipe with a powder coating layer and a resin pipe. SOLUTION: The pipe connecting structure is to connect the resin pipe 2 as an outer member with the steel pipe 1 as inner member by fitting the former on the latter, wherein at the forefront of one end of the steel pipe 1, ring-shaped projections 1a and 1b having an angle-shaped section are formed in such a way as to separated from each other, and a powder coating layer 3 is formed at the periphery of the steel pipe in the range to its other side from the ring- shaped projection 1b positioned on the other side of the steel pipe 1, and when the resin pipe 1 is fitted from one side of the steel pipe 1, the resin pipe 2 will hop over the projections 1a and 1b and reach the powder coating layer 3 to cause overlapping, and in this condition, the steel pipe 1 and resin pipe 2 are connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe connection structure for connecting an inner pipe such as a filler pipe on the fuel tank side of an automobile and an outer pipe such as a filler tube installed on the vehicle body side.

As the inner pipe of this kind, a steel pipe having a strong structure is used, and as the outer pipe, a resin pipe is used for facilitating conformity to the shape of the installation location of the vehicle body or for connecting the steel pipes. There is something to use. Then, in consideration of rust prevention of the steel pipe, the one in which a coating layer is formed using a powder resin such as polyethylene on the peripheral portion is used.

[0003]

2. Description of the Related Art Conventionally, as this type of pipe connection structure, for example, the one shown in FIG. 6 is known.

FIG. 6 shows a vertical cross-sectional view of a conventional pipe connection structure, in which a steel pipe a as an inner pipe is fitted with a resin pipe b as an outer pipe to be connected. .

That is, the steel pipe a has an annular projection c with a mountain-shaped cross section formed at the end on one end side, and a coating layer is formed on the peripheral portion of the other end side of the annular projection c except within a predetermined range d. e is formed and covered.

When the resin pipe b is connected to the steel pipe a, one end side of the resin pipe b is first fitted to the one end side of the steel pipe a and the diameter is expanded by the annular projection c while the coating layer The part d without e was inserted.

[0007]

In the prior art constructed as described above, one end of the steel pipe a is
When the coating layer e is formed on the peripheral portion of the steel pipe a even though there is a portion d without the coating layer e, processing of the separation portion f between the portion d without the coating layer e and the end portion of the coating layer e Since the accuracy cannot be increased so much, an error occurs in the axial dimension of the steel pipe a at the partition f, and a gap g is formed between the partition f of the coating layer e and the resin pipe b. The steel pipe a is exposed to the outside due to the gap f, which may cause rusting at this portion. Also, due to variations in the dimensions and mounting position accuracy of each component and variations in the resin pipe insertion work, when the resin pipe is inserted, the tip of the resin pipe does not abut the partition of the coating layer and a gap is created. , The steel pipe was exposed to the outside through this gap, which could cause rusting at this part.

Therefore, the present invention has been devised in view of the above point, and is devised so that the peripheral portion of the steel pipe is surely covered with the coating layer and the resin pipe so that the peripheral surface is not exposed to the outside. The purpose is to provide a pipe connection structure.

[0009]

In order to achieve the above object, the present invention is, firstly, a pipe connection structure in which a steel pipe as an inner pipe and a resin pipe as an outer pipe are fitted and connected. , An annular projection with a mountain-shaped cross section is projected outward at one end of the steel pipe, and a coating layer is formed on the circumference of the steel pipe on the other end side of the annular projection. When mated from one end side of
The resin pipe is characterized in that both pipes are connected in a state where the resin pipe jumps over the annular projection and reaches the coating layer and is polymerized.

According to the present invention, when the resin pipe is connected to the steel pipe, since the coating layer is present on the peripheral portion of the steel pipe on the other end side of the annular projection, the resin pipe jumps over the annular projection. Immediately after that, the inner diameter of the resin pipe was superposed on the coating layer, and the steel pipe was not exposed to the outside as in the conventional case, and the rust prevention measures are taken as a precaution.

Further, according to the present invention, when the resin pipe is connected to the steel pipe, since the coating layer is present on the peripheral portion of the steel pipe on the other end side of the annular projection, the resin pipe is formed by the annular projection. Immediately after the diameter is increased by one, one end reaches the coating layer, so that even if the steel pipe has a large diameter due to the presence of the coating layer, it can be easily polymerized.

Further, according to the present invention, a bare pipe portion that directly contacts the resin pipe is provided between the coating layer and the annular projection of the steel pipe, and the outer diameter of the bare pipe portion is formed larger than the general outer diameter of the steel pipe. As a result, the diameter of the resin pipe is increased by the annular projection on the other end side, and the subsequent polymerization on the coating layer can be made easier and more reliable.

Further, according to the present invention, it is conceivable to form a recess on the other end side of the steel pipe so that the tip end of the resin pipe opposes, whereby the resin pipe expanded by the annular protrusion on the other end side is formed. When the pipe is superposed on the coating layer, the diameter of the pipe is more reduced by the recesses, so that the superposition on the coating layer can be made easier and more reliable.

The present invention has a second object to achieve the above object.
A pipe connection structure in which a steel pipe as an inner pipe is fitted and connected with a resin pipe as an outer pipe, and a tip end portion on one end side of the steel pipe is separated from each other so as to have an annular cross section. A pair of protrusions are projected outward, and a coating layer is formed on the steel pipe around the annular projection located on the other end side of the steel pipe of the pair of annular protrusions to the other end side. When fitted from one end side of the pipe, the two pipes are connected in a state where the resin pipe jumps over both annular projections and reaches the coating layer and polymerizes.

According to the present invention, when the resin pipe is connected to the steel pipe, the coating layer is present in the peripheral portion of the steel pipe from the annular projection located on the other end side of the steel pipe to the other end side. Immediately after the resin pipe jumps over the annular protrusion on the other end side, the inner diameter of the resin pipe will overlap with the coating layer, preventing the steel pipe from being exposed to the outside as in the past and preventing rust. We are taking all possible measures.

Further, according to the present invention, when the resin pipe is connected to the steel pipe, since the coating layer is present in the peripheral portion on the other end side of the steel pipe with respect to the annular projection on the other end side of the steel pipe, The resin pipe has one end that reaches the coating layer immediately after the diameter is expanded by the annular protrusion on the other end side, and it is very easy if the steel pipe has a large diameter due to the presence of the coating layer. It can be polymerized. After that, the outer periphery of the resin pipe 2 between the annular protrusions 1a and 1b is fastened with a band 4 or the like.

Further, even if the resin pipe is polymerized on the coating layer, the diameter of the resin pipe is expanded by the pair of annular projections, so that the connecting force with the steel pipe does not decrease.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, a pipe connection structure to which the first embodiment of the present invention is applied will be described with reference to FIG.

That is, FIG. 1 is a vertical cross-sectional view depicting a joint portion between a steel pipe and a resin pipe.

In FIG. 1, when a steel pipe 1 as an inner pipe is fitted and connected with a resin pipe 2 as an outer pipe, the steel pipe 1 is enlarged in diameter at one end to form a chevron cross section. The annular projection 1a is provided so as to project outward from one line.

A coating layer 3 made of resin powder such as polyethylene is formed on the peripheral portion of the steel pipe 1 on the other end side of the valley of the annular projection 1a.

Then, when the resin pipe 2 is fitted from one end side of the steel pipe 1, the resin pipe 2 jumps over the annular projection 1a and reaches the coating layer 3, where the resin pipe 2 and the steel pipe 1 are polymerized. It is configured to be connected to the resin pipe 2. Further, the outer periphery of the portion of the resin pipe 2 that overlaps with the coating layer 3 is fastened with a band 4 or the like.

According to the above embodiment, when the resin pipe 2 is connected to the steel pipe 1, the steel pipe 1
Since the coating layer 3 is present in the peripheral portion on the other end side of the annular projection 1a in the above, the inner wall of the resin pipe 2 is superposed on the coating layer 3 immediately after the resin pipe 2 jumps over the annular projection 1a. As a result, the steel pipe a is not exposed to the outside as in the conventional case, and it is taken as a rust preventive measure.

Further, according to the present embodiment, when the resin pipe 2 is connected to the steel pipe 1, the coating layer 3 is formed on the peripheral portion of the steel pipe 1 on the other end side of the annular projection 1a.
Therefore, one end of the resin pipe 2 reaches the coating layer 3 immediately after the diameter is expanded by the annular projection 3, and the steel pipe 1 has a large diameter due to the presence of the coating layer 3. Even if it is, it can be easily polymerized.

FIG. 2 shows a second embodiment, which is a modification of the first embodiment of the present invention, in which a resin pipe is provided between the coating layer 3 and the annular projection 1a of the steel pipe 1. 2 is provided with a bare pipe portion 5 in direct contact with the outer diameter of the bare pipe portion 5 to be larger than the general outer diameter of the steel pipe 1, and is superposed on the coating layer 3 of the resin pipe 2. The outer periphery of the portion is configured by tightening with a band 4 or the like, and the resin pipe 2 is expanded more by the annular projection 1b on the other end side, and subsequent polymerization on the coating layer 3 is easier. And it is intended to ensure.

FIG. 3 shows a third embodiment as a modified example of the first embodiment of the present invention. An annular projection 1b located at the other end side of the steel pipe 1 is shown.
Steel pipe 1 to resin pipe 2 so that
Is formed by fastening the outer periphery of a portion of the resin pipe 2 overlapping the coating layer 3 with a band 4 or the like. The resin pipe 2 whose diameter is expanded by the annular projection 1b on the other end side is reduced in diameter more when polymerized to the coating layer 3, and thus the polymerization to the coating layer 3 can be further simplified. You can be sure.

FIGS. 4 and 5 show a fourth embodiment of the present invention. FIG. 4 is a vertical sectional view showing a joint portion between a steel pipe and a resin pipe, and FIG. 5 is a circle in FIG. FIG.

According to FIG. 4 and FIG. 5, when the steel pipe 1 as the inner pipe and the resin pipe 2 as the outer pipe are fitted and connected to each other, the end portions of the steel pipe 1 on one end side are mutually connected. An annular protrusion 1 with a chevron cross section so that they are spaced apart
a and 1b are projected outward, and annular projections 1a and 1b are provided.
Among these, the coating layer 3 made of resin powder such as polyethylene is formed on the peripheral portion of the steel pipe 1 from the valley portion of the annular projection 1b located on the other end side of the steel pipe 1 to the other end side of the steel pipe 1. Has been done.

When the resin pipe 2 is fitted from one end side of the steel pipe 1, the resin pipe 2 jumps over the annular projections 1a and 1b and reaches the coating layer 3, so that the resin pipe 2 The inner wall is superposed on the coating layer 3, and the steel pipe 1 and the resin pipe 2 are connected in this state.

According to the above construction, when the resin pipe 2 is connected to the steel pipe 1, the circumference of the steel pipe 1 extends from the annular projection 1b located on the other end side of the steel pipe 1 to the other end side. Since the coating layer 3 is present in the resin pipe 2, immediately after the resin pipe 2 jumps over the annular protrusion 1b on the other end side, the inner diameter of the resin pipe 2 is reduced and the resin layer 2 is superposed on the coating layer 3. Conventional steel pipe a
Since there is no part exposed to the outside, it is perfect for rust prevention.

Further, the steel pipe 1 and the resin pipe 2
, The resin pipe 2 has the annular projection 1b on the other end side because the coating layer 3 exists on the peripheral portion on the other end side of the steel pipe 1 from the annular projection 1b on the other end side of the steel pipe 1. Immediately after the diameter of the steel pipe 1 has been expanded, the one end of the steel pipe 1 reaches the coating layer 3, so that the steel pipe 1 can be easily polymerized even if the steel pipe 1 has a relatively large diameter due to the presence of the coating layer 3.

Further, even if the resin pipe 2 is superposed on the coating layer 3, the resin pipe 2 is expanded by the pair of annular projections 1a and 1b formed apart from each other. The connecting force with the pipe 1 does not decrease.

[0034]

As described above, according to the first aspect of the present invention, when the resin pipe is connected to the steel pipe, the coating layer exists on the peripheral portion of the steel pipe on the other end side of the annular projection. Therefore, immediately after the resin pipe jumps over the annular protrusion, the inner diameter of the resin pipe overlaps with the coating layer, preventing the steel pipe from being exposed to the outside as in the conventional method, and preventing rust. As a matter of fact. In addition, when a resin pipe is connected to the steel pipe, since the coating layer exists on the peripheral portion of the steel pipe on the other end side of the annular projection, the resin pipe is When the steel pipe has a large diameter due to the presence of the coating layer, it can be polymerized very easily.

According to the second aspect of the invention, when the resin pipe is connected to the steel pipe, the coating layer is present on the peripheral portion of the steel pipe extending from the annular projection located on the other end side of the steel pipe to the other end side. Therefore, immediately after the resin pipe jumps over the annular projection on the other end side, the inner diameter of the resin pipe will be polymerized in the coating layer, and the conventional steel pipe is not exposed to the outside, Takes all possible measures for rust prevention. Further, when connecting a resin pipe to the steel pipe, since the coating layer is present on the other end side of the steel pipe from the annular projection on the other end side of the steel pipe, the resin pipe is Immediately after the diameter is expanded by the annular protrusion, one end reaches the coating layer, and if the steel pipe has a large diameter due to the presence of the coating layer, it can be polymerized very easily.
Further, even if the resin pipe is polymerized on the coating layer, the diameter of the resin pipe is expanded by the pair of annular protrusions, so that the connection force with the steel pipe does not decrease.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view depicting a joint portion between a steel pipe and a resin pipe in a pipe connection structure to which a first embodiment according to the present invention is applied.

FIG. 2 is a longitudinal sectional view in which a joint portion between a steel pipe and a resin pipe in a pipe connection structure to which a second embodiment according to the present invention is applied is drawn by a radius.

FIG. 3 is a vertical cross-sectional view in which a joint portion between a steel pipe and a resin pipe in a pipe connection structure to which a third embodiment according to the present invention is applied is drawn by a radius.

FIG. 4 is a vertical cross-sectional view depicting a joint portion between a steel pipe and a resin pipe in a pipe connection structure to which a fourth embodiment according to the present invention is applied.

FIG. 5 is an enlarged view of the inside of a circle in FIG.

FIG. 6 is a vertical cross-sectional view depicting a joint portion between a steel pipe and a resin pipe in a conventional pipe connection structure.

[Explanation of symbols]

1 steel pipe 1a annular protrusion 1b Annular protrusion (other end side) 2 resin pipes 3 paint layers 5 Bare tube

Claims (4)

[Claims] 1. A pipe connection structure in which a steel pipe as an inner pipe and a resin pipe as an outer pipe are fitted and connected to each other, and an annular projection having a chevron cross section is formed at an end of one end of the steel pipe. The resin pipe when the resin pipe is fitted from one end side of the steel pipe by forming a coating layer on the peripheral portion of the steel pipe on the other end side of the annular projection. A pipe connection structure in which the both pipes are connected in a state of jumping over the annular protrusion and reaching and reaching the coating layer. 2. A bare pipe portion that directly contacts the resin pipe is provided between the coating layer and the annular projection of the steel pipe, and the outer diameter of the bare pipe portion is larger than the general outer diameter of the steel pipe. The pipe connection structure according to claim 1, wherein the pipe connection structure is formed large. 3. The other end side of the steel pipe,
The pipe connection structure according to claim 1, wherein the resin pipe is formed with a concave portion opposed to the tip end portion thereof. 4. A pipe connection structure in which a steel pipe as an inner pipe is fitted and connected with a resin pipe as an outer pipe, and the tip end portion on one end side of the steel pipe is separated from each other. A pair of annular projections having a chevron cross section are provided so as to project outward, and a coating layer is formed on the peripheral portion of the steel pipe extending from the annular projection located on the other end side of the steel pipe to the other end of the pair of annular projections. Then, when the resin pipe was fitted from one end side of the steel pipe, the resin pipe jumped over both of the annular projections and reached the coating layer and was polymerized to connect the both pipes. A pipe connection structure characterized in that