JP3045824B2 - Manufacturing method of electric fusion joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an electric fusion joint having a fusion portion which is fused to an end of a resin tube by energization.

[0002]

2. Description of the Related Art In general, various types of electro-fusion joints having a fusion-bonded portion adapted to be fused to an end of a resin tube by energization have been proposed.

Heretofore, as a method of manufacturing this kind of electrofusion joint, there has been known a method in which a coil is arranged in a mold in advance, and a resin is injection-molded in the mold. I have.

As shown in JP-T-64-500452, a part of a resin pipe is heated to expand the diameter, a coil is inserted at the time of expansion, and then cooled to reduce the diameter of the expanded part. There has been known a method for manufacturing an electric fusion joint in which a resin tube and a coil are integrated with each other.

[0005]

However, in the case of the above-described conventional manufacturing method, the following inconvenience occurs.

That is, when manufacturing by injection molding, expensive equipment such as an injection molding machine and a mold is required.
Manufacturing costs increase.

In addition, when the coil and the resin tube are manufactured by the method disclosed in Japanese Patent Publication No. Sho 64-500452, the coil and the resin tube are not substantially integrated, and a sufficient connection strength cannot be obtained at the time of fusion. Is generated. further,
Steps such as heating diameter expansion and cooling diameter reduction are complicated, and equipment such as a heating device, a diameter expansion device, and a cooling device are required, thereby increasing the manufacturing cost.

The present invention has been made in view of the above circumstances, and has as its object to provide a method for easily manufacturing an electrofusion joint in which a joint body and a coil are substantially integrated. .

[0009]

According to the present invention, there is provided a method for manufacturing an electro-fusion joint, which is formed in a cylindrical shape, and an end of a resin tube is fitted to an inner peripheral surface of the end. A method for manufacturing an electro-fusion joint in which a fusion-bonded portion formed by burying a coil that generates heat by energization is formed, wherein the diameter of a core made to be expandable and contractible is reduced, and A coil having a coating layer of a resin material wound around the outer periphery, and the core is expanded in a state where the wound portion is inserted into the end of the joint body, whereby the coil is pressed against the inner peripheral surface of the end of the joint body. By energizing the coil, the coating layer of the coil and the inner peripheral surface of the end of the joint body are melted and integrated to form a fused portion.

[0010]

According to the method of manufacturing an electro-fusion joint of the present invention, the core whose diameter can be expanded and contracted is reduced in diameter, and the outer periphery of the core is
A coil having a resin material coating layer is wound, and the core is expanded while the wound portion is inserted into an end of the joint body.
As a result, the coil is pressed against the inner peripheral surface of the end of the joint body. By energizing the coil in this state, the coating layer of the coil and the inner peripheral surface of the end portion of the joint body are melted and integrated to form a fused portion.

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 to 5 show the steps of manufacturing the electrofusion joint 1. FIG.

That is, in the method of manufacturing the electric fusion joint 1, the coil 3 is wound around the outer periphery of the core 2, and the coil 3 is energized while the core 2 is inserted into the end portion 41 of the joint main body 4, and the joint 3 is energized. The coil 3 is integrated with the end 41 of the main body 4 to form the fused portion 10, and the other end 42 of the joint main body 4 and the end 51 of the resin pipe 5 are fused.

The core 2 is configured to be able to expand and contract in diameter.
The structure capable of expanding and contracting the diameter is not particularly limited. Must be able to diameter. For example,
As shown in FIG. 6, a core body 2 formed in a split ring shape
The diameter can be increased by fitting the plug 21 into the split portion of 0, and the diameter can be reduced by removing the plug 21. As shown in FIG. 7, the core 2 is composed of an outer core 22 divided into a plurality of parts and a tapered core 23 inserted into the outer core 22. The diameter of the outer core 22 can be expanded by inserting the tapered core 23, and the diameter can be reduced by removing the tapered core 23.

The material of the core 2 is not particularly limited as long as the material does not deform when the coil 3 generates heat by energizing the coil 3. However,
The heat generated by the coil 3 causes the joint body 4 to melt, but a material that is not melted and integrated with the melted joint body 4 and can be easily separated is used. In the case of a metal material, it is preferable that the surface is coated with an insulating material to prevent electric leakage from the core 2.

The coil 3 has a coating layer 31 made of a thermoplastic resin on its outer surface. This coating layer 31
For example, as shown in FIG. 8, a coating layer 31 having a square cross section can be used. In this case, when the coil 3 is wound around the core 2, it can be wound into a stable cylindrical shape.

Further, as shown in FIG. 9, a fitting portion 32 and a fitting portion 33 may be provided on the coating layer 31. in this case,
While fitting the fitting portion 33 into the fitting portion 32, the joint body 4
The coil 3 can be wound into a stable cylindrical shape without using the core 2 by sequentially feeding the coil 3 into the concave groove 43 from one end 41 of the coil 3. At the same time, in this state, the coil 3 is set in the concave groove 43 formed on the inner peripheral surface of the joint body 4, so that it is not necessary to use the core 2.

The thermoplastic resin forming the coating layer 31 is not particularly limited, but the same material as the joint body 4 may be used for the coil 3 and the joint body 4.
Is preferable in that they are strongly integrated.

The joint body 4 is formed in a cylindrical shape.
On the inner peripheral surface of the one end portion 41, the coil 3 in the wound state is provided.
Is formed. The groove 43 is provided with a terminal hole 44 penetrating from the groove 43 to the outer peripheral surface.
Each end of the cable can be inserted. Furthermore, the other end 42 side of the joint body 4 is tapered so that the end 51 of the resin pipe 5 can be inserted.

Next, a method of manufacturing the electric fusion joint 1 will be described.

As shown in FIG. 1, first, one end of the coil 3 is temporarily fixed to the core 2, and the coil 3 is wound around the core 2. After the winding, the other end is also temporarily fixed to the core 2. Fix it.

At this time, the diameter of the core 2 is reduced. Further, it is preferable that the winding width W1 of the coil 3 is equal to or slightly smaller than the width W2 of the concave groove 43 of the joint body 4.

Next, the core 2 is inserted from one end 41 side of the joint main body 4 and, as shown in FIG.
Are inserted into the terminal holes 44. At this time, the coil 3 is inserted into the terminal hole 44 with a sufficient margin.

Next, the diameter of the core 2 is expanded. Then, the coil 3 that has been inserted with a sufficient margin from the terminal hole 44 is drawn into the joint body 4, and the coil 3 is fitted into the concave groove 43 of the joint body 4, and the core 2
As a result, it comes into pressure contact with the concave groove 43.

Then, as shown in FIG. 3, the coating layer 31 of the coil 3 inserted into the terminal hole 44 is peeled off, electrodes are connected, and the coil 3 is energized. Thereby, the coating layer 3
1 and the joint body 4 in the vicinity of the coating layer 31 are melted and integrated to form a fused portion 10.

Thereafter, the diameter of the core 2 is reduced and the core 2 is extracted from the joint body 4.

Finally, as shown in FIGS. 4 and 5, the other end 42 of the joint body 4 and the end 51 of the resin pipe 5 are melted by the heat welding machine 6, and the other end of the joint body 4 is melted. By inserting and integrating the end portion 51 of the resin tube 5 into 42, the electrofusion joint 1 having the fusion portion 10 is obtained.

In the electric fusion joint 1 thus formed, the other end of the other electric fusion joint 1 is inserted into the fusion portion 10 of the electric fusion joint 1 to energize the coil 3, or the coil 3 is energized. Insert the end 51 of the resin tube 5 corresponding to the fusion portion 10 and insert the coil 3
, The connection between the electric fusion joints 1 or between the electric fusion joint 1 and the resin pipe 5 can be achieved.

In the present embodiment, the joint body 4 and the resin tube 5 are finally integrated to form the electro-fusion joint 1 having the fusion portion 10, as shown in FIG. To
The end portion 51 of the resin tube 5 is heated and expanded by the sleeve mold 7.
May be applied to form the fused portion 10 directly at the end 51 of the resin tube 5.

Further, in this embodiment, the fused portion 10 is formed at one end, but as shown in FIG. 11, the socket member 8 having the terminal hole 84 and the concave groove 83 formed at both ends.
By using, an electric fusion joint having fusion parts at both ends can also be manufactured.

[0031]

As described above, according to the present invention, the coil is pressed against the inner peripheral surface of the end of the joint body by the expansion and contraction diameter of the core, and the coil is energized, so that the coating layer of the coil and the joint body are Thus, a fused portion can be formed by fusing and integrating the inner peripheral surface of the end portion, so that an electrofusion joint can be easily manufactured without requiring a special equipment such as an injection molding machine.

Further, since the coating layer of the coil and the inner peripheral surface of the end of the joint body are melted and integrated to form a fused portion, the coil and the joint body are substantially integrated. Sufficient connection strength can be obtained at the time of fusion.

[Brief description of the drawings]

FIG. 1 is a process diagram showing a state where a coil is wound around a core and inserted into a joint body.

FIG. 2 is a process diagram showing a state in which each end of a coil inserted into a joint main body is inserted into a terminal hole to expand the diameter of a core.

FIG. 3 is a process diagram showing a state in which the core is reduced in diameter and removed after energizing the coil.

FIG. 4 is a partially broken side view showing a state in which the joint main body and the resin pipe are melted by a welding machine.

FIG. 5 is a partial cross-sectional view showing a state in which the joint body and the resin pipe are integrated into an electric fusion joint.

FIG. 6 is a cross-sectional view showing one embodiment of a core.

FIG. 7 is a sectional view showing another embodiment of the core.

FIG. 8 is a partial perspective view showing one embodiment of a coil.

FIG. 9 is a partial perspective view showing another embodiment of the coil.

FIG. 10 is a process chart showing a method of manufacturing an enlarged-diameter portion for forming a fused portion at an end of a resin tube.

FIG. 11 is a sectional view showing a socket member for manufacturing an electric fusion joint having fusion parts at both ends.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric fusion joint 10 Fusion part 2 Core 3 Coil 31 Coating layer 4 Joint main body 41 One end part (end part) 43 Depressed groove (end inner peripheral surface) 5 Resin tube 51 end part

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁷ Identification code FI B29L 31:24

Claims (1)

(57) [Claims] An end portion of an inner peripheral surface of a cylindrical portion is provided with a fusion-bonded portion in which an end of a resin tube is fittable and a coil which generates heat when energized is buried. A method for manufacturing an electro-fusion joint, comprising reducing a diameter of a core which is made expandable and contractible, winding a coil having a resin material coating layer around the outer periphery of the core, and connecting the wound portion to a joint body. The core is expanded in a state where it is inserted into the end portion, and thereby the coil is pressed against the inner peripheral surface of the end portion of the joint body, and by energizing the coil, the coating layer of the coil and the inner peripheral surface of the end portion of the joint body are formed. A fusion-bonded part to form a fusion-bonded part.