JPH0818349B2 - Welding joint forming apparatus and welding joint forming method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a welding joint molding apparatus for welding and joining synthetic resin pipes such as gas pipes and water pipes, and a manufacturing method for producing the welding joint. .

(Prior Art) A molding apparatus for molding a welded joint includes a mandrel fitted inside an outer mold, and a conductive wire winding region around which a coated conductive wire is wound is formed and formed on an outer peripheral surface of the mandrel. In some cases, a step is formed at the boundary between the conductive wire winding area and the outside of the winding area so that the covered conductive wire can be locked. Further, conventionally, the step is arranged in the circumferential direction of the mandrel.

(Problems to be Solved by the Invention) However, in the above-described conventional molding apparatus, a step is simply formed on the outer peripheral surface of the mandrel, and this step is wound when the coated conductive wire is wound around the mandrel. It does not function as a guide guide unit that determines the starting direction. Therefore, it is very difficult to wind the coated conductive wire around the mandrel at a constant pitch. That is, there is a problem that the pitch of the coated conductive wire becomes non-uniform due to individual differences and skill levels of workers, and variations in quality are likely to occur.

Also, since there is always a gap between the step of the mandrel and the first circumference of the coated conductive wire, when the cavity is filled with resin, the coated conductive wire moves due to the axial resin pressure, which results in fusion. There is also a risk of causing a short circuit when joining.

It is an object of the present invention to provide a molding apparatus and a molding method capable of manufacturing a high quality welded joint in which covered conductive wires are embedded at a constant pitch, focusing on the above-mentioned conventional problems.

(Means for Solving the Problem) In order to achieve this object, a welding joint molding apparatus according to claim 1 of the present invention includes a mandrel fitted inside an outer mold, and a conductive coating is provided on an outer peripheral surface of the mandrel. A conductive wire winding region around which the wire is wound is provided, and a step capable of locking the covered conductive wire is formed at a boundary between the conductive wire winding area and the outside of the winding area, and the step has a predetermined pitch. It is arranged in the spiral direction. Further, a method for forming a welding joint according to claim 2 of the present invention is a method of winding a conductive wire around a conductive wire winding region of the mandrel according to claim 1, and a step of winding the conductive wire around the mandrel after the step. Fit inside,
A molding step of filling a thermoplastic resin into a cavity formed between the outer die and the mandrel to form a welded joint, and locking the coated conductive wire to the step of the mandrel in the conductive wire winding step. It is a method of winding the first lap in the state of being made.

(Operation) The operation of the present invention will be described.

In the welding joint molding apparatus according to claim 1 of the present invention and the welding joint molding method according to claim 2, when the coated conductive wire is wound around the conductive wire winding region of the mandrel, the conductive wire is locked to the step of the mandrel. By winding the first lap with
From the second round, the coated conductive wire can be wound around the mandrel arranged in the spiral direction at a constant pitch simply by winding the coated conductive wire in the first round as a reference.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view showing a welding joint forming apparatus of the present embodiment, in which 1 is a mandrel.

The mandrel 1 has a structure that can be divided into two parts in the axial direction, and is fitted inside an outer mold (not shown) to form a cavity between the mandrel 1 and the outer mold.

A conductive wire winding area 1a around which the coated conductive wire 2 is wound is provided on the outer peripheral surface of the mandrel 1, and the mandrel 1 is provided at the boundary between the conductive wire winding area 1a and the outside of the winding area 1b.
Steps 12a, 12b, 12c, ... that can be engaged with the coated conductive wire 2 by a plurality of projections 11a, 11b, 11c, ...
・ 12i is formed. The protrusions 11a, 11b, 11c, ... 1
A plurality of 1i are arranged at positions where the outer periphery of the mandrel 1 is equally divided, and the steps 12a, 12 of the protrusions 11a, 11b, 11c, ...
.. 12i are arranged in a spiral direction with a pitch p substantially equal to the diameter of the coated conductive wire 2.

Next, a method for forming the welding joint of this embodiment will be described.

This forming method is performed by using the forming apparatus in the order of the covered conductive wire winding step and the forming step.

First, in the coated conductive wire winding step, the coated conductive wire 2 is spirally wound around the conductive wire winding region 1a of the mandrel 1 with a constant tension. At this time, the steps 12a, 12b, 12c, ... 12i of the protrusions 11a, 11b, 11c, ... 11i formed on the mandrel 1
Are arranged in the spiral direction, so by winding the first turn in a state where the covered conductive wire 2 is locked to the steps 12a, 12b, 12c, ... 12i of the mandrel 1, from the second turn. The coated conductive wire 2 can be wound around the mandrel 1 at a constant pitch simply by winding the coated conductive wire 2 in the first round as a reference.

Further, since the pitch of the steps 12a, 12b, 12c, ... 12i is equal to the diameter of the coated conductive wire 2, the coated conductive wire 2 should be wound around the mandrel 1 so that there is no gap between the front and rear circumferences. become.

After winding the coated conductive wire 2 around the mandrel 1, a coating layer of the adjacent coated conductive wires 2 may be fused by pressing a heating tool such as a trowel. At that time, it is preferable to perform at two or more locations in the circumferential direction.

The coated conductive wire 2 is a conductive wire such as Cu wire, Ni wire, or MnNi alloy wire coated with a thermoplastic resin such as polyethylene resin, polyvinyl chloride resin, or polybutene resin, and has a coating thickness of 0.4. ~ 1.0mm is desirable.

In the molding step, the mandrel 1 is fitted inside the outer mold, and a cavity formed between the mandrel 1 and the outer mold is filled with a thermoplastic resin to mold the welding joint. Before fitting the mandrel 1 into the outer mold, the terminal pins 3 are connected to both ends of the coated conductive wire 2, and the terminal pins 3 are placed outside the winding area 1b and at a part of the outer mold. Indicate the upper end. Further, since the filled thermoplastic resin and the coating layer of the coated conductive wire 2 are melted and integrated, the coated conductive wire
As shown in FIG. 3, 42 is also embedded in the inner peripheral portion of the joint body 41.

The thermoplastic resin with which the cavity is filled is preferably the same material as the thermoplastic resin used for the coating layer of the coated conductive wire 2, and may be a combination of different materials that are compatible with each other.

FIG. 3 is a sectional view showing a welded joint manufactured by the manufacturing method.

As described above, in the forming apparatus and the forming method of the present embodiment, in the covered conductive wire winding step, the covered conductive wire 2 is simply wound around the conductive wire winding area 1a of the mandrel 1 at a constant pitch. Therefore, it is possible to manufacture a high quality welded joint 4 in which the coated conductive wires 42 are embedded in the inner peripheral portion of the joint body 41 at a constant pitch.

In addition, in the conductive wire winding step, the coated conductive wire 2 is wound so that a gap is not formed between the first round and the step of the mandrel 1, and the gap is not formed between the front and rear sides. In the next molding step, when the cavity is filled with resin, the coated conductive wire 42 is applied by the resin pressure in the axial direction.
Will not move. As a result, a short circuit does not occur during fusion bonding.

The embodiment of the present invention has been described in detail above with reference to the drawings.
The specific configuration and method are not limited to this embodiment, and modifications and the like within the scope of the present invention are included in the present invention.

For example, in the embodiment, the step formed so that the coated conductive wire can be locked is formed on the protrusion integrally formed on the mandrel, but for example, a paper magnet having a step where the coated conductive wire can be locked is attached to the mandrel. May be.

Further, the step of each protrusion may be at least 1/2 the diameter of the covered conductive wire or more. Further, instead of each protrusion, a step may be formed continuously in a spiral shape in the circumferential direction.

(Effects of the Invention) Since the welding joint molding apparatus according to claim 1 of the present invention and the welding joint molding method according to claim 2 are configured as described above, the coated conductive wires are embedded at a constant pitch. It is possible to obtain an effect that a high quality welded joint can be manufactured.

[Brief description of drawings]

FIG. 1 is a side view showing a welding joint molding apparatus of an embodiment of the present invention, FIG. 2 is a side view showing steps of a manufacturing method using the molding apparatus, and FIG. 3 is a welding manufactured by the manufacturing method. It is sectional drawing which shows a joint. 1 ... Mandrel 1a ... Conductive wire winding area 1b ... Outside the winding area 12a, 12b, ... 12i ... Step 2 ... Coated conductive wire

Claims (2)

[Claims] 1. A mandrel fitted inside an outer mold, wherein a conductive wire winding area around which a coated conductive wire is wound is provided on an outer peripheral surface of the mandrel, and the conductive wire winding area and the outside of the winding area are provided. A step for forming a covered conductive wire is formed at a boundary of the step, and the step is arranged in a spiral direction of a predetermined pitch. 2. A conductive wire winding step of winding a coated conductive wire around a conductive wire winding area of the mandrel according to claim 1, and after the step, the mandrel is fitted inside an outer mold to form an outer mold and a mandrel. And a molding step of molding a welded joint by filling a thermoplastic resin into a cavity formed between the conductive wire winding step and the coated conductive wire locked to the step of the mandrel. A method for forming a welding joint, which comprises winding the first round.