JP3152735B2 - 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 for manufacturing an electro-fusion joint formed by using a sheath tube.

[0002]

2. Description of the Related Art In general, there is known an electric fusion joint in which a coil which generates heat by energization is embedded in an inner peripheral surface of a joint body.

Conventionally, as one method of manufacturing this electrofusion joint, a sheath tube is put on an outer peripheral portion of a coil wound around an outer core, and these are set in a mold, and the outer core is connected to the outer core. A method is known in which a sheath material and a coil are integrated with a resin material by injecting a resin material into a gap between the mold and the resin (for example, see Japanese Patent Application Laid-Open No. 2-293121).

[0004]

However, in the case of the above-mentioned conventional method for manufacturing an electro-fusion joint, since the space between the coil wound around the outer core and the sheath tube is narrow, the sheath tube is attached to this coil. If the coil is set in the mold, the position of the coil cannot be checked and corrected from the outside, making it difficult to perform axial positioning. As a result, the electrofusion joint in a state where the coil in the sheath tube is displaced is formed, and a short circuit and a connection failure at the time of energization occur.

[0005] It is also conceivable that the sheath tube and the coil are positioned in advance and then set in the mold. However, when the coil is set in the mold, the position of the coil comes into contact with the mold. It often shifts, and even if positioning is performed outside the mold, positioning within the mold cannot be performed firmly.

The present invention has been made in view of the above circumstances, and has as its object to provide a method of manufacturing an electro-fusion joint in which a coil is positioned at a desired position in a sheath tube without displacement. .

[0007]

According to the present invention, there is provided a method for manufacturing an electro-fusion joint, which comprises covering a sheath tube constituting an outer layer of a joint body on the outside of a coil in a wound state. A method in which a tube and a coil are arranged in a mold, and a resin material is injected into a gap between the sheath tube and the coil to form an electro-fusion joint. In this method, the sheath tube and the coil are arranged in the mold. Previously, the sheath tube and the coil are fused and integrated by a fusion member.

[0008]

According to the present invention, before the sheath tube and the coil are arranged in the mold, the sheath tube and the coil are fused and integrated by the fusion member, so that the positional relationship between the sheath tube and the coil is firmly established. It can be placed in the mold in the positioned state.

[0009]

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

FIG. 1 shows an outline of the whole structure of the electrofusion joint 1, and FIG. 2 shows a main part of a manufacturing process of the electrofusion joint 1.

That is, in the method of manufacturing the electro-fusion joint 1, the sheath tube 3 constituting the outer layer of the joint body 10 is put on the outside of the coil 2 in the wound state, and the sheath tube 3 and the coil 2 are molded ( (Not shown), a resin material 4 is injected into a gap between the sheath tube 3 and the coil 2 to form the electro-fusion joint 1, and the sheath tube 3 and the coil 2 are molded in a mold ( The sheath tube 3 and the coil 2 are fused and integrated by the fusion member 5 before being arranged in the housing (not shown).

The outer periphery of the coil 2 is covered with a resin layer 21. First, the coil 2 is spirally wound so that the resin layers 21 are in close contact with each other, and the cylindrical bobbin 20 is wound.
Formed. In this state, the inner diameter of the coil 2 is formed so as to correspond to the inner diameter of the electrofusion joint 1. Then, terminals 22 for energization are connected to both ends of the coil 2.

Next, the fusing members 5 are fused at four locations on the outer peripheral surface on one end side of the bobbin 20 at appropriate intervals. As shown in FIG. 3, the fusing member 5 is formed in a plate shape having a stepped portion 51. The stepped portion 51 is in contact with the outer peripheral surface of the end of the bobbin 20, and the electric iron (shown in FIG. (Omitted), etc. The number of the fusion members 5 to be fused is not particularly limited to four, and an appropriate number of the fusion members 5 may be fused if necessary.

Then, the sheath tube 3 is put on the bobbin 20 to which the fusion member 5 is fused. At this time, the sheath tube 3 is
A hole 31 is formed at a position where the current-carrying terminal 22 is to be inserted. For this reason, this hole 31
To cover the coil 2 with the sheath tube 3. Further, in this state, a gap is formed between the sheath tube 3 and the coil 2, which is an unstable state where positioning is not performed.

Therefore, after positioning the bobbin 20 in the sheath tube 3, the fusing member 5 fused to the bobbin 20 f
The other end side of the sheath tube 3 is connected with an electric iron (not shown).
Is fused to the inner peripheral surface. To position the bobbin 20, as shown in FIG. 3, the other end of the fusion member 5 is previously set as a fusion member 5 having a predetermined length L, and the other end of the fusion member 5 is Positioning can be performed by matching with the end of the sheath tube 3. Also, as shown in FIG.
Positioning can also be performed using a positioning jig 6 adapted to allow the bobbin 20 to be inserted at a distance A from the end of the sheath tube 3.

As described above, the bobbin 20 and the sheath tube 3 integrated by the fusing member 5 are arranged in a mold (not shown) by inserting a core (not shown) in the bobbin 20, By injecting the resin material 4 into the gap with the sheath tube 3, the electrofusion joint 1 is formed.

In this embodiment, the bobbin 20 and the sheath tube 3 are fused and integrated by the plate-like fusion member 5, but the present invention is not limited to such a plate-like one. Instead, it may have a rod shape or other various shapes. After positioning, the molten resin may be partially injected between the bobbin 20 and the sheath tube 3 with a hot melt gun (not shown) to achieve integration, or a welding rod (not shown).
For example, the molten resin may be partially melted for integration.

The shape of the electrofusion joint 1 is not limited to the shape shown in FIG. 1, but the outer layer of the joint body 10 is constituted by the sheath tube 3 and the sheath tube 3 is provided with a bobbin. The present invention can be applied to the production of various electrofusion joints as long as they are formed by arranging 20. For example,
As shown in FIG. 4, the bobbin 2 which is not provided with the energizing terminal 22 but is simply constituted by the coil 2 in a wound state.
By arranging 0 in the sheath tube 3 and molding, an electrofusion joint by electromagnetic induction heating can be molded.

[0019]

As described above, according to the present invention, the sheath tube and the coil can be arranged in the mold in a state where the positional relationship between the sheath tube and the coil is firmly positioned. A simple electric fusion joint can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing an overall configuration of an electrofusion joint.

FIG. 2 is a process chart showing a main part of a method for manufacturing an electric fusion joint.

FIG. 3 is a process chart showing an example of a method for positioning a sheath tube and a bobbin.

FIG. 4 is a sectional view showing another embodiment of a method for positioning a sheath tube and a bobbin.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric fusion joint 10 Joint main body 2 Coil 3 Sheath tube 4 Resin material 5 Fusion member f Fusion

Claims (1)

(57) [Claims] 1. A sheath tube constituting an outer layer of a joint body is put on the outside of a coil in a wound state, and after the sheath tube and the coil are arranged in a mold, a resin material is placed in a gap between the sheath tube and the coil. To form an electro-fusion joint by injecting the sheath tube and the coil by a fusion member before disposing the sheath tube and the coil in the mold. A method for manufacturing an electric fusion joint.