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CN-122003319-A - Method for manufacturing resin tube

CN122003319ACN 122003319 ACN122003319 ACN 122003319ACN-122003319-A

Abstract

The invention provides a method for manufacturing a resin pipe, which can improve the durability and the sealing performance of a pipe joint externally embedded and fastened with a hose and reduce the weight. Cutting off the space between one end part (17 a) and one end part side discharging cavity (17 d) of the cavity (17), filling the molten resin (R1) ejected from the one end part (17 a) into the cavity (17), cutting off the communication path between the one end part (17 a) and the injection machine (11), communicating the one end part (17 a) and the one end part side discharging cavity (17 d), injecting auxiliary materials (As) from the other end part (17 b), discharging excessive molten resin (R1) from the cavity (17) to the one end part side discharging cavity (17 d), solidifying the tubular molten resin (R1) remained in the cavity (17) to form a resin pipe (1), and forming a fitting protrusion (4 b) which is fitted with a notch part (6 a) of the core pipe (5) in the pipe joint (4), so As to limit the axial and circumferential movement of the core pipe (5) embedded in the pipe joint (4).

Inventors

  • HOU GANG
  • KURIBAYASHI NOBUMASA

Assignees

  • 横滨橡胶株式会社

Dates

Publication Date
20260508
Application Date
20240624
Priority Date
20231030

Claims (6)

  1. 1. A method for manufacturing a resin tube, the resin tube comprising: A tubular fitting to which an externally fitted hose is fastened, and A metal core pipe which is disposed in a predetermined range including the entire length of a fastening range for fastening the hose in the longitudinal direction of the pipe joint and is embedded in the pipe joint, The core tube and the pipe joint are provided with a limiting part for limiting the axial and circumferential movement of the core tube relative to the pipe joint, the pipe joint and the core tube are integrated at the front end part in the length direction, Wherein a cavity having one end portion and the other end portion and extending therebetween for forming the resin pipe, a pipe joint forming portion provided at the other end portion, and an end portion side discharge cavity extending outside the cavity and communicable with the one end portion are provided in advance in the mold, The core tube is arranged in the pipe joint forming part, the molten resin is injected from the one end part to the other end part by an injection machine in a state that the communication between the one end part and the cavity for one end part side discharge is cut off and the mold is locked, the molten resin is filled in the cavity, after that, the state that the communication between the one end part and the injection machine is cut off and the one end part and the cavity for one end part side discharge are communicated is set, And injecting an auxiliary material from the other end portion toward the one end portion, and discharging an excess of the molten resin from the cavity to the one end portion side discharge cavity, whereby the resin pipe is formed by using a cured resin obtained by curing the cylindrical molten resin remaining in the cavity, and the restricting portion of the pipe joint is formed so as to restrict axial and circumferential movement of the core pipe relative to the pipe joint, and the core pipe is fitted in the pipe joint.
  2. 2. The resin pipe according to claim 1, wherein the core pipe has a cutout portion at a front end portion thereof, the cutout portion being disposed outside the fastening range in a longitudinal direction of the pipe joint, and the restriction portion is constituted by a cured resin obtained by causing a part of the molten resin to enter the cutout portion and cure, and the cutout portion.
  3. 3. The resin tube according to claim 1 or 2, wherein the resin tube has a concave-convex portion formed on an outer peripheral surface of the core tube, and wherein the restriction portion is formed by a cured resin which is cured by entering the concave portion and the concave portion by allowing a part of the molten resin to enter the concave portion of the concave-convex portion.
  4. 4. The method for producing a resin tube according to any one of claims 1 to 3, wherein the resin tube has a double-layer structure in which an inner tube portion and an outer tube portion formed of cured resins of different specifications are coaxially laminated, A cavity for discharging the other end part side which extends outside the cavity and is communicated with the other end part is arranged in the die in advance, The molten resin is injected into the cavity so that the outer tube molten resin forming the outer tube portion and the inner tube molten resin forming the inner tube portion are filled in a cylindrical shape into the cavity, the inner tube molten resin is filled in a cylindrical shape into the inner peripheral side of the cylindrical outer tube molten resin, and the excess molten resin is discharged to the other end side discharge cavity, And injecting an auxiliary material from the other end portion toward the one end portion, and discharging an excess of the molten resin from the cavity to the one-end-side discharge cavity, thereby solidifying the cylindrical molten resin remaining in the cavity to form the resin tube.
  5. 5. The method for producing a resin tube according to claim 4, wherein only the outer tube molten resin contains reinforcing short fibers in the molten resin.
  6. 6. The method for producing a resin pipe according to any one of claims 1 to 5, which uses a gas as the auxiliary material.

Description

Method for manufacturing resin tube Technical Field The present invention relates to a method for manufacturing a resin pipe, and more particularly, to a method for manufacturing a resin pipe capable of improving durability and sealing properties while suppressing deformation of a pipe joint in which a hose is externally fitted and fastened, and realizing weight saving. Background Various structures for fitting and fixing a pipe body to a pipe joint are known in the art (for example, refer to patent documents 1 and 2). Patent document 1 discloses a structure in which a first low-pressure pipe made of resin is fitted and fixed to a first tube made of resin (corresponding to a pipe joint) (paragraphs [0020] to [0023], fig. 2, and the like). Patent document 2 discloses a structure in which a resin pipe is fitted and fixed to a press-fitting portion (corresponding to a pipe joint) of a quick connector (paragraph [0013], fig. 1, etc.). In recent years, various studies have been made on using a resin pipe instead of a metal pipe in order to reduce the weight of pipes used in vehicles such as automobiles. In a resin pipe having a pipe joint at a front end portion, a hose is fitted and fastened to the pipe joint. Specifically, after the hose is externally fitted to the nipple, the hose fitting externally fitted to the distal end portion of the hose is fastened, whereby the hose is firmly fixed to the nipple. The resin pipe joint of the resin pipe has lower rigidity than the metal pipe joint of the metal pipe. Therefore, in a simple resin pipe, when the hose is fastened and fixed, the resin pipe joint is easily deformed, and there is a problem that durability and sealability between the hose and the pipe joint are lowered as compared with the pipe joint of a metal pipe. Accordingly, there is room for improvement in terms of suppressing deformation of the pipe joint in which the hose is externally fitted and fastened to improve durability and sealability, and achieving weight saving. Prior art literature Patent literature Patent document 1 Japanese patent No. 6714784 Patent document 2 Japanese patent laid-open No. 2004-263729 Disclosure of Invention Problems to be solved by the invention The invention provides a method for manufacturing a resin pipe, which can restrain deformation of a pipe joint externally embedded and fastened with a hose, improve durability and sealing performance and realize light weight. Solution for solving the problem In order to achieve the above object, in the method for producing a resin tube according to the present invention, the resin tube includes a tubular pipe joint to which an externally fitted hose is fastened, and a metal core pipe disposed in a predetermined range including a whole length of a fastening range to which the hose is fastened in a longitudinal direction of the pipe joint and fitted in the pipe joint, the core pipe and the pipe joint include a regulating portion regulating movement of the core pipe in an axial direction and a circumferential direction of the pipe joint, the pipe joint and the core pipe are integrally provided at a front end in the longitudinal direction, a cavity having one end portion and the other end portion and extending between the one end portion and the other end portion is provided in advance in a mold, for forming the resin tube, a pipe joint molding portion provided at the other end portion, and an end portion side discharge cavity extending outside the cavity and being communicable with the one end portion, the pipe joint is disposed at the pipe joint, the core pipe joint is cut off portion, the core pipe joint is disposed at the front end portion, the core pipe joint is integrally connected to the injection molding portion from the other end portion toward the one end portion to the other end portion by way of the injection molding machine, the injection molding cavity is opened from the other end portion toward the other end portion to the one end portion, and the injection molding cavity is opened from the other end portion toward the other end portion is opened, and the injection molding cavity is opened to the other end portion is filled, the resin pipe is formed by using the solidified resin solidified from the molten resin remaining in the cylindrical shape of the cavity, and the restricting portion of the pipe joint is formed to restrict the axial and circumferential movement of the core pipe relative to the pipe joint, so that the core pipe is fitted in the pipe joint. Effects of the invention According to the present invention, the resin pipe in which the metal core pipe is fitted in the pipe joint and integrated can be manufactured. In the resin pipe, the core tube is fitted in a predetermined range including the entire length of the fastening range for fastening the hose in the longitudinal direction of the pipe joint, so that the rigidity of the fastening range is improved. Therefore, even if the hose is fastened to the coupling