JPH04332632A - Manufacture of joint hose - Google Patents

Abstract

PURPOSE:To dissolve the variability of the stress-strain of rubber hose developed in the resin covering part of the bonded part between the hose and pipe during the manufacture process in order to give stable and high sealing properties to the hose concerned. CONSTITUTION:The manufacturing of the joint hose concerned consists of an inserting process, in which a core pipe 1 is inserted in the ends of rubber hoses 2 in order to produce the point hose 5, a temperature retaining process, in which the pipe inserted part of the joint hose 5 is heated up to the predetermined temperature and kept at the temperature, and a covering process, in which the surface of the pipe inserted part heated and kept hot is covered by resin 3 by arranging the part in a mold for insert molding.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a joining hose for connecting branch hoses and the like.

0002

[Prior Art] Conventional methods for manufacturing jointed hoses include inserting the end of a rubber hose into a core pipe, and fixing the surface of the rubber hose with a clip or metal band, or covering and molding it with a molding material to integrate it. A method of locking and joining is known. In this method, the joint part of the rubber hose is coated with resin to improve the sealing performance of the joint surface.The molding pressure of the resin molding material injected during insert molding applies stress strain to the joint surface of the rubber hose, and its elastic force is used to create a tight seal. Improves sealability and maintains sealing properties. However, even if the applied molding pressure is kept constant, a predetermined stress strain cannot be applied to the rubber hose connected to the pipe, resulting in variations in sealing performance. It is presumed that this is because the elastic modulus of the rubber hose varies during the coating process, which causes variation in stress strain and does not improve the sealing performance at the joint surface.

0003

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to eliminate variations in stress distortion of rubber hoses that occur in the resin-coated portion of the joint portion during the manufacturing process, and to achieve a stable and high level of stress distortion. The purpose is to provide sealing properties.

0004

[Means for Solving the Problems] The method for manufacturing a joined hose of the present invention includes an insertion step of inserting a core pipe into an end of a rubber hose to form a joined hose, and a portion of the joined hose into which the pipe is inserted. A heat retention step in which the pipe is heated to a predetermined temperature, and a coating step in which the heated and heat-retained portion of the joint hose into which the pipe is inserted is placed in a mold and the surface is coated with resin by insert molding. Features.

[0005] The spliced hose formed according to the present invention includes:
The end of the hose is joined to a core pipe for branching or connection, and the surface of the rubber hose at the joint is covered with a coating resin to fix the joint and maintain sealing performance. In this joint hose manufacturing method, first, in an insertion step, the end of the rubber hose is inserted into the core pipe up to a predetermined position. This core pipe connects the ends of the rubber hoses to be joined to prevent deformation of the tubular diameter of the rubber hose due to stress distortion during resin coating, and joins the inner peripheral surface of the rubber hose to the outer peripheral surface. The core pipe is usually made of hard resin, and preferably has a ring-shaped protrusion on the outer peripheral surface of the joint to prevent the rubber hose from coming off. A normal rubber hose is used as the hose, and a rubber hose reinforced with fibers or the like may be used.

In the heat retention step, the joint hose formed in the insertion step is placed in a mold maintained at a predetermined temperature and held until the rubber hose reaches a predetermined temperature. Usually, the rubber hose is heated until it reaches 40-60°C. This heat retention makes the rubber hose relatively soft and increases its elasticity, and a predetermined amount of stress strain can be applied to the rubber hose by the molding pressure during insert molding, thereby preventing variations in deformation.

In the coating process, a molding material is injected onto the surface of the joint hose heated to a predetermined temperature by insert molding. The rubber hose is compressed and deformed by injection pressure and contraction of the molded body, and its surface is coated with resin. At this time, the rubber hose is heated and maintains a substantially constant elasticity, so there is little variation in compressive deformation due to substantially constant stress strain. Therefore, the sealing force generated is stable, and the solidified coating resin covers and seals the outer circumferential surface of the rubber hose.
In addition, the rubber hose can be firmly sealed to the core pipe.

[0008] The resulting joined hose has no variation in deformation due to stress strain of the rubber hose caused by resin pressure during coating molding, and can maintain high sealing performance by preventing variations in sealing performance between the rubber hose, core pipe, and coating resin. This is because the elasticity of the rubber hose covered by the heating process can be maintained constant, so there is no variation in elasticity due to changes in the outside temperature of the combined hose, and there is no variation in sealing performance due to differences in the degree of compressive deformation during molding. It can be resolved. In particular, it is possible to suppress the deterioration of sealing performance that occurs in winter when the temperature of the rubber hose is low. Furthermore, since the joint hose can be heated in the mold before molding, no new equipment is required. Therefore, a coupled hose with stable sealing properties and less variation can be easily manufactured without increasing costs.

[0009]

[Operation] According to the method for manufacturing a bonded hose of the present invention, the temperature of the rubber forming the rubber hose is constant because the bonded hose is heated to a predetermined temperature in the mold before being coated with resin. This increases the elasticity of the rubber hose and eliminates variations in compressive deformation. Therefore, the jointed hose covered with the molded resin is firmly locked by the coating resin, and the sealing performance on both the coating resin surface of the rubber hose and the contact surface with the core pipe can be improved.

0010

[Examples] Hereinafter, the present invention will be explained in detail using examples. Figure 1
As shown in the figure, this jointed hose consists of a core pipe 1 made of hard resin having a three-pronged opening into which the ends of three rubber hoses are inserted, three rubber hoses 2, and a core pipe 1 joined to the core pipe 1. It consists of a coating resin 3 that covers the surface of the rubber hose 2 and locks the hose.

[0011] This method of manufacturing a jointed hose includes an insertion step,
The heat retention process and the coating process are performed in sequence. In the insertion step, the ends of each rubber hose 2 are inserted into the core pipe 1 and joined together to form a joined hose 5 shown in FIG. 2. This core pipe 1 is made of nylon resin containing 30% by weight glass fiber, and a plurality of ring-shaped protrusions 4 for preventing the hose from coming off are formed on the outer circumferential surface of the joint portion to prevent and lock the rubber hose 2 from coming off. The rubber hose 2 was made of EPDM and had a rubber hardness of 60.

In the heat retention step, the joint hose 5 is placed in a predetermined mold (not shown), the temperature of the mold is maintained at approximately 60°C, and the temperature of the joint hose 5 is heated until the temperature reaches 40°C. did. By maintaining the rubber hose 2 at this temperature, the rubber hose 2 has increased elasticity and can be maintained in a state where compressive deformation is almost reproducible under a constant molding pressure load.

In the covering step, a covering resin (nylon resin) is press-fitted by injection molding into the coupling hose 5 held for insert molding and is kept warm in a mold to perform covering molding. The molding conditions at this time were: resin temperature 280-290℃;
Injection pressure 49.0×106 Pa Mold gate hole diameter 1.
5 mm, and the spool runner diameter is 5 to 6 mm. Under these conditions, the rubber hose 1 with a wall thickness of 4 mm in cross section is 3 to 3.5 mm.
It was possible to compress and deform up to Therefore, the sealing performance of the resin-coated joint hose was improved.

[0014] If the coating process is delayed without going through the heating process as in the conventional method, the thickness of the cross section will be 4 mm.
The rubber hose has undergone compression deformation of about 3.5 to 4 mm, and in some cases, it has not undergone any compression deformation. This tends to happen especially in winter when the temperature of the hose is low. In such a case, the sealing performance deteriorates and the variation becomes large.

[0015]

According to the method for manufacturing a bonded hose of the present invention, the rubber hose is heated and maintained at a predetermined temperature before the bonded hose is coated with resin. For this reason, the elasticity of the rubber hose increases and the amount of compressive deformation increases, resulting in almost constant compressive deformation due to molding pressure. As a result, the sealing performance of the joined hose after molding the coated resin can be ensured, and there is no variation in the sealing performance. As a result, the jointed hose can have improved sealing performance.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a joining hose of this embodiment.

FIG. 2 is a sectional view of the coupling hose of this embodiment.

[Explanation of symbols]

1 core pipe, 2 rubber hose, 3 coating resin, 5 joint hose,

Claims (1)

[Claims] Claim 1: an insertion step of inserting a core pipe into the end of a rubber hose to form a joint hose; a heat insulation step of heating and keeping the part of the joint hose into which the pipe is inserted to a predetermined temperature; A method for manufacturing a jointed hose, comprising a coating step of arranging the part of the jointed hose into which the pipe is inserted in a mold and coating the surface with a resin by insert molding.