JPH0747297B2 - Manufacturing method of welded joint - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a joint for fusion-bonding synthetic resin gas pipes and water pipes.

(Prior Art) Conventionally, as a method for manufacturing a joint for fusion-bonding synthetic resin pipes, for example, a method for manufacturing a pipe joint as described in JP-B-57-33480 is known.

This conventional method includes a tubular body forming step of forming a tubular body in which a conductive wire net is embedded in a thermoplastic resin layer, an installation step of installing the tubular body in a mold core, and a tubular body. The core is placed in a mold, the mold is filled with a thermoplastic resin, and the joint is injection-molded to form a joint.

(Problems to be Solved by the Invention) However, in such a conventional manufacturing method,
Since a pipe joint in which a wire mesh is inserted in the inner circumference of the joint body is manufactured, when joining a synthetic resin pipe and applying a constant voltage to the metal mesh of this pipe joint, the current will flow only through the shortest line. The resin around the shortest path is locally heated without being energized. That is, the welding of the synthetic resin pipes is only partially performed, often resulting in defective joints.

The present invention focuses on the above problems, and provides a manufacturing method capable of manufacturing a welded joint capable of preventing a short circuit and uniformly weld-bonding a synthetic resin pipe.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this object, the method for manufacturing a welded joint of the present invention is In a method for manufacturing a welded joint in which a conductive material is arranged on an inner peripheral portion, a mold having a core having an inner peripheral molding surface for molding an inner peripheral surface of a joint main body is provided as a mold for the joint. A mat formed by using a coated conductive wire coated with a thermoplastic resin as a conductive material, laying the coated conductive wire on a flat surface, and adhering adjacent coated conductive wires to each other to form a mat. A molding step, a step of installing the mat-shaped covered conductive wire molded in the mat molding step on the inner peripheral molding surface of the core, and after the step, a thermoplastic resin is filled in the mold for injection molding. It consists of the joint forming process This is the method used.

(Working) When manufacturing a welded joint, first spread the coated conductive wire on a flat surface. The shape to be spread is a shape corresponding to the inner peripheral surface of the joint body. Then, the adjacent covered conductive wires are adhered to each other to be molded into a mat (mat forming step).

Next, the coated conductive wire formed in a mat shape is installed on the inner peripheral molding surface of the core of the mold (installation step).

Next, the core is placed at a predetermined position of the mold, the molten thermoplastic resin is filled in the mold, and the joint is injection-molded (joint molding step).

In the joint manufactured in this manner, the conductive wire is arranged in the inner peripheral portion of the joint body, and a constant voltage is applied to the conductive wire in a state where the synthetic resin pipe is inserted inside the joint body. By energizing, it is possible to weld and join synthetic resin pipes.

(Examples) Examples of the present invention will be described in detail below with reference to the drawings.

First, the structure of the embodiment shown in FIGS. 1 to 7 will be described.

In this embodiment, a socket A as shown in FIG. 7 is taken as an example of the joint, and a molding method of this socket A will be described.

In the method of manufacturing the socket A of this embodiment, the mold 1,
The coated conductive wire 2, the box type 3, and the heater 4 are used.

The mold 1 has an outer mold 11 and a core (inner mold) as shown in FIG.
It has 13 and. An outer peripheral molding surface 11a for molding the outer peripheral surface of the socket body 10 is formed inside the outer mold 11, and an inner peripheral surface of the socket body 10 is molded on the outer peripheral surface of the core 12. An inner peripheral molding surface 12a is formed. The core 12 is installed in the mold 1 so that a constant gap 13 is secured between the outer peripheral molding surface 11a and the inner peripheral molding surface 12a.

The coated conductive wire 2 is a conductive wire 21 coated with a polyethylene resin (resin coating 22), and the conductive wire 21 is a Cu wire.

The resin coating 22 is not limited to the polyethylene resin, and a thermoplastic resin such as polypropylene resin, polyvinyl chloride resin, or polybutene can be used. Its coating thickness is 0.
4 to 1.0 mm is desirable.

Further, the conductive wire is not limited to the Cu wire, but Ni wire, MnNi alloy wire, or the like can be used. The diameter is preferably 0.2 to 0.9 mm.

Next, a method of manufacturing the socket A using these will be described. This manufacturing method consists of a mat forming process, an installation process,
The molding steps are performed in this order.

(Mat forming step) First, one long covered conductive wire 2 is formed into a rectangular box 3
Spread it over. At this time, the covered conductive wire 2 is laid repeatedly by repeating the folding from the upper edge to the lower edge of the box mold 3 (see FIG. 1).

After laying the coated conductive wire 2 on the entire box 3 in this way,
Covering the heater 4 provided integrally with the box mold 3 with the conductive wire 2
One side of the resin coating 21 is melted by covering it on the above, and the adjacent portions of the coated conductive wire 2 are welded by the melted resin (see FIG. 2). By doing so, the coated conductive wire 2 is formed into a square mat shape (see FIG. 3).

(Installation Step) Next, the covered conductive wire 2 formed in a mat shape is wound in a tubular shape (see FIG. 4). At this time, the coated conductive wire 2 is wound from the folded end portion of the coated conductive wire 2 and is wound in a tubular shape.
Is installed so as to be wound around the inner peripheral molding surface 12a of the core 12 of the mold 1.

Further, after the coated conductive wire 2 is installed on the core 12, terminal pins 5 are installed on both ends of the conductive wire 21 (FIG. 5).

(Molding Step) Next, the core 12 is integrally installed with the coated conductive wire 2 and the terminal pin 5 at a predetermined position of the mold 1, and the resin of the coated conductive wire 2 is placed in the gap 14 between the female die 11 and the core 12. A thermoplastic resin of the same material as the coating 21 is filled and injection molding is performed. Incidentally, 14 is a fixing jig for fixing the terminal pin 5, which is fixed to the core 12 in advance and installed in the mold 1 integrally with the core 12 (see FIG. 6).

The resin is injected from the spool 15 into the gap 13.

At this time, the pressure generated by the ejection of the resin tightens the winding of the coated conductive wire 2 around the core 12 to ensure the reliability. At this time, the resin coating 22 of the coated conductive wire 2 is compatible with and integrated with the resin injected from the spool 15.

The resin material filled in the gap 13 does not necessarily have to be the same as the material of the resin coating 22 of the coated conductive wire 2, and different types of resins may be combined as long as they are compatible with each other. Good. As a combination of compatible resins, for example, ABS resin is used for the resin coating 21, PVC
A combination of using a resin for the socket body 10 and a combination of using a PVC-based elastomer resin for the resin coating 21 and using a PVC resin for the socket body 10 are also included.

Through the above steps, the conductive wire is formed on the inner peripheral portion of the socket body 10.
A socket A in which 21 is inserted is manufactured (see FIG. 7).

In the method of this embodiment, since the socket A is manufactured by using the coated conductive wire 2, the conductive wires 21 are inserted in a winding state with a certain space therebetween.

In this socket A, the synthetic resin pipe 6 is inserted inside the end portion, and by applying a constant voltage from the terminal pin 5, the conductive wire 21 is heated to melt the thermoplastic resin around the conductive wire 21, and the synthetic resin The pipe 6 can be welded and joined. As described above, the socket A has the conductive wire 21.
Are wound at regular intervals, there is no risk of short circuit, and the conductive line 21 as a whole can be energized. Thereby, the conductive wire 21 is entirely welded to the synthetic resin pipe 6 in the inner peripheral portion of the joint body 10 into which the conductive wire 21 is inserted, and a reliable joined state can be obtained.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within a range not departing from the gist of the present invention. included.

For example, in the embodiment, when forming the coated conductive wire into a mat shape, the covering conductive wire is laid out in a rectangular shape, but the shape is such that branch joints other than sockets, elbows, reducers, etc.
It may be changed depending on the shape of the joint to be molded. For example,
When forming the branch joint, it is easy to use if it is formed into a circular shape or an elliptical shape.

Further, the work of spreading the covered conductive wires may be performed by turning without being folded back. Particularly when it is desired to form a circular or elliptical mat, it is easier to arrange the shape by swirling and spreading.

(Effects of the Invention) As described above, in the method for manufacturing a welded joint of the present invention, it is possible to prevent a short circuit, ensure an energized state in the entire conductive wire, and securely weld and join the synthetic resin pipe. It is possible to obtain the effect that it is possible to manufacture a welded joint.

[Brief description of drawings]

1 to 3 are perspective views illustrating a mat forming process in a method for manufacturing a socket according to an embodiment of the present invention, FIGS. 4 and 5 are perspective views illustrating an installation process, and FIG. 6 is a forming process. FIG. 7 is a longitudinal sectional view for explaining, and FIG. 7 is a longitudinal sectional view showing a socket molded by the method of this embodiment. A …… Socket (joint) 10 …… Socket body (joint body) 1 …… Mold 12 …… Core 12a …… Inner peripheral molding surface 2 …… Coating Conductive wire 21 …… Conductive wire 22 …… Resin coating

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area // B29L 31:24

Claims (1)

[Claims] 1. A method for manufacturing a welded joint in which a conductive material is disposed on an inner peripheral portion of a joint body, wherein a die of the joint has an inner peripheral molding surface for molding the inner peripheral surface of the joint body. Using a mold provided with a core, and using a coated electric wire coated with a thermoplastic resin as a conductive material, and laying the coated conductive wire on a flat surface,
A mat forming step of adhering parts of adjacent coated conductive wires to each other to form a mat, and a step of installing the mat-shaped coated conductive wires formed in the mat forming step on the inner peripheral molding surface of the core, A method of manufacturing a welded joint, comprising a joint molding step of performing injection molding by filling the mold with a thermoplastic resin after the step.