JPH0765709B2 - 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 is disclosed in
As described in Japanese Patent Laid-Open No. 63-71323, it includes a mandrel and an outer mold into which the mandrel is fitted. Further, in the method for forming a welding joint employing this forming apparatus, a conductive wire winding step of winding a coated conductive wire around the outer peripheral surface of the mandrel, and after the step, the mandrel is fitted inside the outer mold, There is a molding step of molding a welded joint by filling a thermoplastic resin into a cavity formed between the mold and the mandrel, and in the conductive wire winding step, there is a right part of the outer surface of the mandrel. The coated conductive wire is tightly wound on the left portion, and the coated conductive wire is roughly wound on the central portion of the outer peripheral surface of the mandrel.

(Problems to be Solved by the Invention) However, in the conventional molding apparatus, the outer peripheral surface of the mandrel is a region (the right part and the left part) where the coated conductive wire is densely wound.
Since there is no distinction between the rough winding area and the rough winding area (center part), the winding state of the coated conductive wire varies due to individual differences and skill levels in the conductive wire winding process, making it difficult to maintain consistent quality. There was a problem.

Moreover, since there is nothing that locks the coated conductive wire on the outer peripheral surface of the mandrel, the coated conductive wire is moved by the resin pressure during the molding process, and the balance of the arrangement state of the coated conductive wire is deteriorated. There are also problems.

An object of the present invention is to provide a molding apparatus and a molding method capable of manufacturing a high quality welded joint in which the winding state of the coated conductive wire is less likely to vary, focusing on the above conventional problems.

(Means for Solving the Problem) In order to achieve this object, in the welding joint molding apparatus according to claim 1 of the present invention, the mandrel outer peripheral surface is formed in the right part and the left part in the central part outer peripheral surface of the mandrel. A strip-shaped raised portion is provided around each of the divided portions, and the outer peripheral surface of the raised portion is formed with a conductive wire guide groove spirally connecting the right portion and the left portion of the mandrel outer peripheral surface. . Further, a method for forming a welding joint according to claim 2 of the present invention comprises a conductive wire winding step of winding a coated conductive wire around an outer peripheral surface of the mandrel according to claim 1, and the mandrel being placed inside an outer mold after the step. A molding step of fitting a thermoplastic resin into the gavity formed between the outer mold and the mandrel, and forming a welded joint, the conductive wire winding step, the central portion of the mandrel outer surface Except for the part where the coated conductive wire is tightly wound, the coated conductive wire is locked to the edge of the raised portion, and at the center of the outer peripheral surface of the mandrel, the coated conductive wire is locked to the conductive wire guide groove of the raised portion and wound. Is the way to do so.

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

In the welding joint molding apparatus according to the first aspect of the present invention, since the mandrel outer peripheral surface is divided into the right portion and the left portion by the belt-shaped rising portion, the rising portion is provided around the outer surface of the mandrel. By adopting the welding joint forming method described in 2, the following is obtained.

First, in the conductive wire winding step, for example, when winding the coated conductive wire from the left side to the right side of the mandrel, the left edge of the rising portion is a stopper that prevents unwinding of the coated conductive wire wound around the left portion of the mandrel outer peripheral surface. The right edge of the rising part serves as a guide for starting winding to the right part of the outer surface of the mandrel. As a result, the work of winding the coated conductive wire can be performed efficiently, and variations in the winding state are unlikely to occur due to individual differences, skill levels, and the like.

Next, in the molding step, the covered conductive wire is prevented from moving due to the resin pressure because the covered conductive wire is locked to the edge of the rising portion of the mandrel and the conductive wire guide groove. As a result, it is possible to manufacture a welded joint in which the arrangement state of the coated conductive wires is well balanced.

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

FIG. 1 is a side view showing a mandrel of a molding apparatus of this embodiment, and FIG. 2 is a sectional view of the mandrel, in which 1a is a mandrel left part, 1b is a mandrel right part, and 2 is a bobbin.

The mandrel left part 1a and the mandrel right part 1b are joined by fitting the projection 11 and the recess 12. Also, the left part of the mandrel
A plurality of protrusions 13a and 13b are integrally formed of metal on the left and right ends of the outer periphery of the mandrel 1 in which the mandrel 1a and the right mandrel 1b are joined.

The protrusions 13a, 13b are for locking the coated conductive wire when the coated conductive wire is wound around the outer peripheral surface of the mandrel 1.
They are arranged in a circle. The engagement surfaces 131a and 131b of the protrusions 13a and 13b are formed in a spiral shape, and the pitch P1
Is set to be substantially equal to the diameter of the coated conductive wire 3.
Furthermore, the height of each protrusion 13a, 13b may be at least 1/2 the diameter of the covered conductive wire or more.

The bobbin 2 has a cylindrical shape into which the right end of the left mandrel 1a and the left end of the right mandrel 1b can be inserted at both ends. That is, the bobbin 2 is mounted on the outer peripheral surface of the central portion of the mandrel 1, and in that state,
It becomes a raised portion that partitions the outer peripheral surface of the mandrel 1 into a left portion and a right portion. An annular groove 14 is formed in the joint between the left mandrel portion 1a and the right mandrel portion 1b, and an annular protrusion that fits into the annular groove 14 is formed on the inner peripheral surface of the bobbin 2.
21 are formed.

The bobbin 2 is a synthetic resin molded product such as polyethylene resin having a thickness of about 1 to 5 mm (approximately the same as the diameter of the coated conductive wire), and the left and right edges 2a and 2b are formed in a spiral shape. The pitch P2 is set to be substantially equal to the diameter of the coated conductive wire. Further, on the outer peripheral surface of the bobbin 2, a conductive wire guide groove 22 is spirally formed around the outer peripheral surface of the mandrel left portion 1a and the outer peripheral surface of the mandrel right portion 1b, and the conductive wire guide groove 22 is formed. The width of the groove 22 is set to be substantially equal to the diameter of the covered conductive wire.

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 3 is spirally wound around the outer peripheral surface of the mandrel 1 with a constant tension. Regarding the winding state, the outer peripheral surface of the mandrel left portion 1a and the outer peripheral surface of the mandrel right portion 1b are tightly wound, and the outer peripheral surface of the bobbin 2 is wound once. At this time, the covered conductive wire 3 is locked to both edges 2a, 2b of the bobbin 2 and the conductive wire guide groove 22, and the projection 1
It is locked to the locking surfaces 131a, 131b of 3a, 13b.

Then, for example, when the coated conductive wire 3 is wound from the left side to the right side of the mandrel 1, the protrusion 13a of the mandrel left part 1a serves as a guide for starting winding to the mandrel left part 1a, and the right edge 2b of the bobbin 2 is It will be a guide to start winding to the right part 1b of the mandrel. Since the locking surface 131a of the protrusion 13a and the right edge 2b of the bobbin 2 are formed in a spiral shape having a pitch substantially equal to the diameter of the coated conductive wire 3, after the first winding is finished, the second surface is The covered conductive wire 3 can be easily wound tightly.

In addition, the left edge 2a of the bobbin 2 serves as a stopper for preventing unwinding of the coated conductive wire 3 on the left mandrel portion 1a, and the protrusion 13b of the right mandrel portion 1b prevents unwinding of the coated conductive wire 3 on the right mandrel portion 1b. It becomes a stopper. As a result, it is possible to perform the sticking operation of the coated conductive wire 3 efficiently, and it is unlikely that the winding state of the coated conductive wire 3 varies due to individual differences and skill levels.

In addition, after winding the coated conductive wire 3 around the mandrel 1, the coating layer of the adjacent coated conductive wire 3 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 3 is a conductive wire such as a Cu wire, a Ni wire, or an MnNi alloy wire coated with a thermoplastic resin such as a polyethylene resin, a polyvinyl chloride resin, or a polybutene resin, and has a coating thickness of 0.4. ~ 1.0mm is desirable.

In the molding process, the terminal pins 4 are attached to both ends of the coated conductive wire 3.
And the terminal pin 4 is erected at a position outside the protrusions 13a and 13b to support the upper end portion thereof. Then, the mandrel 1 is fitted inside the outer mold,
A thermoplastic resin is filled in the cavity formed between the outer mold and the outer mold to form a welded joint.

At this time, the covered conductive wire 3 has the engaging surfaces 131a and 131b of the protrusions 13a and 13b.
Also, since the left and right edges 2a and 2b of the bobbin 2 and the conductive wire guide groove 22 of the bobbin 2 are engaged, it is possible to prevent the covered conductive wire 3 from moving due to resin pressure. As a result, as shown in FIG. 4, a welded joint in which the coated conductive wires 3 are arranged in a well-balanced manner can be manufactured. Further, the filled thermoplastic resin and the bobbin 2 and the coating layer of the coated conductive wire 3 are melted and integrated.

The thermoplastic resin to be filled in the cavity is preferably the same material as the thermoplastic resin used for the coating layer of the bobbin 3 and the coated conductive wire 2, but it is a combination of different materials compatible with each other. Good.

Although 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 the present invention can be applied even if there are changes within the scope not departing from the gist of the present invention. included.

For example, in the embodiment, the raised portion of the mandrel is formed by a bobbin made of synthetic resin and formed separately from the mandrel, but the raised portion may be integrally formed of metal with the mandrel. When using the bobbin, the bobbin may be formed into a split ring so that the left part of the mandrel and the right part of the mandrel can be joined together and then the bobbin can be attached to the outside of the joining part.

Further, the mandrel may be formed with a spirally continuous step instead of the plurality of protrusions, or a paper magnet having a wall thickness capable of locking the coated conductive wire may be attached to the mandrel. .

Further, in the embodiment, the molding device and the molding method of the socket-shaped welding joint are shown, but the present invention may be applied to a welding joint having a branch portion or a vent-shaped welding joint. In that case,
The shape of the bobbin and the like will be appropriately changed according to the shape of the mandrel.

(Effects of the Invention) A molding apparatus for a welding joint according to claim 1 of the present invention and claim 2
Since the forming method of the welding joint described is configured as described above, it is difficult to cause variations in the winding state of the coated conductive wire due to individual differences and proficiency, and it is possible to manufacture a high quality welding joint. The effect is obtained.

[Brief description of drawings]

FIG. 1 is a side view showing a mandrel of a molding apparatus of an embodiment of the present invention, FIG. 2 is a sectional view of the mandrel, and FIG. 3 is a side view showing a conductive wire winding step of a manufacturing method using the molding apparatus. FIG. 4 is a sectional view showing a welding joint manufactured by the manufacturing method. 1 ... Mandrel 2 ... Bobbin (raised part) 22 ... Conductive wire guide groove 3 ... Coated conductive wire

Claims (2)

[Claims] 1. A mandrel outer peripheral surface is provided with a belt-shaped swelling portion that divides the mandrel outer peripheral surface into a right portion and a left portion, and the outer peripheral surface of the swelling portion has a mandrel outer peripheral surface. An apparatus for forming a welding joint, characterized in that a conductive wire guide groove is formed in a spiral shape so as to connect the right part and the left part. 2. A conductive wire winding step of winding a coated conductive wire around an outer peripheral surface of the mandrel according to claim 1, and, after the step, the mandrel is fitted inside an outer mold to provide a space between the outer mold and the mandrel. A forming step of filling the formed cavity with a thermoplastic resin to form a welded joint, and in the step of winding the conductive wire, the coated conductive wire is densely wound in a portion other than the central portion of the outer peripheral surface of the mandrel. The coated conductive wire is locked at the edge of the raised portion, and the coated conductive wire is locked in the conductive wire guide groove of the raised portion at the center of the outer peripheral surface of the mandrel so that it can be wound. Molding method.