CN-122003322-A - Method for manufacturing pipe with resin joint

Abstract

A method for manufacturing a pipe with a resin joint, comprising a pretreatment step for roughening the outer surface of an end (11E) of a metal pipe (11), a first attachment step for attaching a resin joint (12) to the roughened end (11E), a heating step for heating the attachment portion of the metal pipe (11) and the resin joint (12) in a state in which the resin joint (12) is attached to the metal pipe (11), a pressing step for pressing the resin joint (12) from the outside of the resin joint (12) to the inside of the metal pipe (11), a cooling step for cooling the resin joint (12), and a second attachment step for attaching a reinforcing member (13) to the outer surface portion of the resin joint (12) after cooling the resin joint (12). The linear expansion coefficient of the reinforcing member (13) is smaller than that of the resin joint (12).

Inventors

• NAKADAI KAZUO
• TETSURO SAKANO
• MAEDA KOICHI

Assignees

• 株式会社日轮

Dates

Publication Date

20260508

Application Date

20241011

Priority Date

20231016

Claims (7)

1. 1. A method for producing a pipe with a resin joint, wherein a resin joint is joined to a metal pipe, characterized by comprising the steps of: a pretreatment step of roughening an outer surface of an end portion of the metal pipe; a first mounting step of mounting a cylindrical resin joint on the end of the roughened metal pipe; A heating step of heating a mounting portion of the metal pipe and the resin joint in a state where the resin joint is mounted on the end portion of the metal pipe; a pressing step of pressing the resin joint from the outside of the resin joint to the inside of the metal pipe in a state where the metal pipe and the mounting portion of the resin joint are heated; a cooling step of cooling the resin joint after pressing the resin joint inward of the metal pipe, and A second mounting step of mounting a reinforcing member on an outer surface portion of the resin joint on an outer side of the end portion of the metal pipe after cooling the resin joint, The linear expansion coefficient of the reinforcing member is smaller than that of the resin joint.
2. 2. The method for producing a pipe with a resin joint according to claim 1, wherein, In the heating process, in the course of the heating process, The metal pipe and the mounting portion of the resin joint are heated by heating the metal pipe by a heating device.
3. 3. The method for producing a resin-bonded pipe according to claim 1 or 2, wherein, The reinforcing member is a cylindrical member.
4. 4. The method for producing a resin-bonded pipe according to claim 1 or 2, wherein, In the second mounting process step of the present invention, The reinforcing member is pressed toward the resin joint in the radial direction of the resin joint, and the inner surface of the reinforcing member is brought into close contact with the outer surface of the resin joint.
5. 5. The method for producing a resin-bonded pipe according to claim 1 or 2, wherein, In the second mounting process step of the present invention, The reinforcing member having an inner diameter equal to or smaller than an outer diameter of the resin joint is press-fitted into the resin joint from an axial direction of the resin joint, and an inner surface of the reinforcing member is brought into close contact with an outer surface of the resin joint so that the reinforcing member is disposed outside the resin joint.
6. 6. The method for producing a resin-bonded pipe according to claim 1 or 2, wherein, The outer surface of the resin joint has a tapered portion with an outer diameter that increases as it approaches one end in the axial direction, The reinforcing member is a cylindrical member and, The inner surface of the reinforcing member has a tapered portion whose inner diameter becomes larger as approaching one end in the axial direction, In the second mounting process step of the present invention, In the axial direction of the resin joint, the direction in which the outer diameter of the resin joint is increased and the direction in which the inner diameter of the reinforcing member is increased are the same, and the reinforcing member is press-fitted into the resin joint, the inner surface of the reinforcing member is closely attached to the outer surface of the resin joint so that the reinforcing member is disposed outside the resin joint.
7. 7. The method for producing a resin-bonded pipe according to claim 1 or 2, wherein, The metal pipe and the resin joint are cylindrical, In the pressing step, the resin joint is pressed from the outer side of the resin joint to the inner side of the end portion of the metal pipe in the radial direction of the resin joint in a state where the metal pipe and the mounting portion of the resin joint are heated.

Description

Method for manufacturing pipe with resin joint Technical Field The present invention relates to a method for producing a pipe with a joint made of resin. Background Conventionally, a method of joining different kinds of materials with high joining strength or high sealing property has been proposed. For example, patent document 1 describes a method of joining a metal molded body and a resin molded body. In the method described in patent document 1, after roughening the metal molded body, the surface of the resin molded body corresponding to the first roughened portion is welded to the first roughened portion in a state where the resin molded body is pressed against the roughened first roughened portion. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2022-3045 Disclosure of Invention Problems to be solved by the invention The joining of dissimilar materials is also useful in the case of connecting pipes of dissimilar materials to one another. For example, when a metal pipe is connected to a resin pipe, a resin joint may be used. In this case, the resin joint is joined to a metal pipe as a material different from the resin joint. The above-described structure may be used for a vehicle pipe used in a vehicle, for example. In this case, the inside of the vehicle is at a high temperature, and a fluid such as a refrigerant of an air conditioner (air conditioner) for the vehicle flows in the pipe at a high pressure for a long period of time. Even under such severe conditions, it is desirable to maintain high sealing properties at the joint portion of different kinds of materials such as a resin joint and a metal pipe. The present inventors have produced a pipe with a resin joint by roughening a metal pipe and attaching a resin joint to the roughened portion as in the method described in reference 1. Further, an experiment was performed to simulate a severe condition in a vehicle using a pipe with a resin joint. As a result, it was found that the fluid flowing through the pipe leaked from between the resin joint and the metal pipe. The invention provides a method for manufacturing a pipe with a resin joint, which has high sealing performance. Means for solving the problems The method for manufacturing a pipe with a resin joint disclosed in the present specification is a method for manufacturing a pipe with a resin joint, wherein a resin joint is joined to a metal pipe, and the method comprises a pretreatment step of roughening the outer surface of the end of the metal pipe, a first installation step of installing a cylindrical resin joint on the roughened end of the metal pipe, a heating step of heating the installation portion of the metal pipe and the resin joint in a state where the resin joint is installed on the end of the metal pipe, a pressing step of pressing the resin joint from the outer side of the resin joint to the inner side of the metal pipe in a state where the installation portion of the metal pipe and the resin joint is heated, a cooling step of cooling the resin joint after the resin joint is pressed to the inner side of the metal pipe, and a second installation step of cooling the resin joint, after the resin joint is cooled, the expansion coefficient of the reinforcing wire joint is smaller than that of the resin joint is installed on the outer surface portion of the resin joint. In the present specification, "tube" means a tubular member. In this specification, the "tube" includes a component called "hose" and a component called "tube" in addition to a component called "tube". According to the above method, the resin joint is pressed from the outside of the resin joint to the inside of the metal pipe in a state where the metal pipe and the mounting portion of the resin joint are heated. Thus, the resin joint is fitted into the plurality of recesses in the outer surface of the roughened end portion of the metal pipe, and the resin joint is tightly bonded to the end portion of the metal pipe with little gap between the resin joint and the end portion of the metal pipe. The resin joint is cooled in a state where there is almost no gap between the resin joint and the end of the metal pipe and the resin joint is in close contact with the end of the metal pipe, whereby the resin joint is solidified. After the resin joint is cured in the above state, the reinforcing member is mounted. In the above state, the reinforcing member is not attached to the resin joint until the resin joint is cured. Thus, even if the resin joint expands when the metal pipe with the resin joint is used at a high temperature and then the resin joint contracts due to a decrease in temperature, a gap hardly occurs between the resin joint and the reinforcing member. Further, since the linear expansion coefficient of the reinforcing member is smaller than that of the resin joint, the resin joint can be restrained from expanding outward at a high temperature by the reinforcing me