JPH05260625A - Method of molding power cable splice - Google Patents

Abstract

PURPOSE:To provide a method of molding a cable splice with reinforcement insulator containing no foreign matter. CONSTITUTION:A transparent tube 3 is provided hermetically over both insulators 1 of cables to be connected before a mold 10 is set. Then, the metallic mold 10 is provided outside and the transparent tube 13 is filled with a resin melted by heat so that an insulating body is formed for the splice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a connection portion of a rubber / plastic power cable.

[0002]

2. Description of the Related Art FIG. 3 is an explanatory view showing a vertical cross section of an example of a conventional method for forming a rubber and plastic power cable connecting portion. After the conductor and the insulator of the cable to be connected are stripped off, the conductor is compressed using a conductor connecting pipe to obtain the conductor connecting portion 2. After that, the inner surfaces of the cable insulator 1 and the mold 10 are wiped to check that there is no foreign matter, and the mold 10 is installed over the insulator 1 of both cables to be connected by including the conductor connecting portion 2 therein. Then, after that, the heat-melted resin is injected into the internal space of the mold 10 through the injection pipe 11 attached to the resin injection port 10a of the mold 10 to form the reinforcing insulator integrated with the cable insulator 1. .. After cooling, the mold 10 is removed, and the surface of the reinforcing insulator is finished to form the required reinforcing insulator A shown by the one-dot chain line.

[0003]

In the conventional forming method described above, even if the inner surface of the mold and the insulator are wiped and inspected before the cable insulator is covered with the mold, it is confirmed that there is no foreign matter. However, foreign matter sometimes adhered to the surface of the cable insulator until it was covered with a mold. Further, the more time it takes to inspect, the easier it is for foreign matter to enter. Therefore, conventionally, it has been attempted to reduce foreign matter as much as possible by increasing the cleanliness of the surrounding environment covered with a mold.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a method for forming a power cable connecting portion which enables the molding of a reinforced insulator free from foreign matter. Before installing the mold, provide a transparent tube in an airtight manner over the insulators of both cables to be connected, and then install a mold on the outside and inject the heat-melted resin into the transparent tube. Forming a reinforced insulator.

[0005]

In the present invention, although it takes some time to inspect foreign matters, it was considered that the state between the inspection of foreign matters and the installation of the mold should be hermetically sealed. However, if the sealed state prevents foreign matter from entering, it is necessary to check the foreign matter in this state. Therefore, the problem was solved by using a transparent tube as the container to be sealed. After making a sealed state with a transparent tube in this way and confirming that there is no foreign matter, a mold is installed on the outside and a resin can be injected into the transparent tube to form a foreign matter-free reinforced insulator. It will be possible.

As the transparent tube, a glass tube, F
A material having a higher melting point than the melting point of the resin to be injected into the interior after EP, EEA, PEEK, ETFE, or the like and having good transparency can be used.

[0007]

EXAMPLES FIGS. 1 (a) and 1 (b) are explanatory views showing a longitudinal section showing a procedure of a specific example of the forming method of the present invention. As a transparent tube, a transparent and hard material such as glass or PEEK is used. Here is an example. First, in a hard transparent tube 3 such as a glass tube, an injection hole 3a is opened in advance at a position corresponding to the resin injection port 10a of the mold 10 and sealed with a tape 4. Then, as shown in FIG. 1A, the hard transparent tube 3 is covered with the conductor connecting portion 2 on the insulator 1 of both cables to be connected, and both ends thereof are sealed with the packing 5 or the like. After confirming that there is no foreign matter on the inner surface of the tube 3 and the surface of the cable insulator 1 with a magnifying glass or CCD camera 6, etc., the tape seal 4 of the injection hole 3a of the transparent tube 3
At the same time as peeling off, as shown in FIG. 1B, a mold 10 is installed on the outside thereof. Then, the resin injection port 10 of the mold 10
A resin such as uncrosslinked polyethylene that has been heated and melted is injected into the transparent tube 3 from the injection tube 11 attached to a, and after the resin is crosslinked and solidified by cooling, the mold 10 and the transparent tube 3 are removed, and reinforced insulation is performed. The body is formed. As a result of evaluating the electrical performance of the obtained reinforced insulator, it was confirmed that the reinforced insulator had the required electrical performance.

2A and 2B are explanatory views showing a longitudinal section showing the procedure of another specific example of the forming method of the present invention, in which a relatively flexible material such as EEA or FEP is used as the transparent tube. The example used is shown below. As shown in FIG. 2A, the insulator 1 of both cables to be connected by including the conductor connecting portion 2 therein.
The transparent tube 7 made of a relatively flexible material such as EEA is covered so as to cover the upper part, and both ends thereof are squeezed and tightened with a band 8 or the like for sealing. Then, the presence or absence of foreign matter on the inner surface of the transparent tube 7 and the surface of the cable insulator 1 is checked with a magnifying glass or the CCD camera 6. It is preferable for this transparent tube to be closer to the outer diameter of the cable insulator 1 than to match the inner diameter of the mold 10 in terms of foreign object observation accuracy. In the experiment, the outer diameter of the cable insulator 1 is 100 mm.
The inner diameter of the transparent tube 7 was 110 mmφ with respect to φ.

Inner surface of transparent tube 7 and cable insulator 1
After confirming that there is no foreign matter on the surface, a mold 10 is installed on the outside of the transparent tube 7 as shown in FIG. After the transparent tube 7 is softened by preheating the mold 10, a vacuum 12 is drawn inside the mold 10 from the resin injection port 10a of the mold 10 and a part of the transparent tube 7 is discharged from the resin injection port 10a. Come on. Further pull the vacuum 12 and the transparent tube 7 bulges 7a as shown. Then, the bulging portion 7a of the transparent tube 7 is cut off, an injection pipe is attached to the resin injection port 10a of the mold 10, and a resin such as uncrosslinked polyethylene that has been heated and melted is injected into the transparent tube 7 and cooled and solidified. The mold 10 is removed and the transparent tube 7 is shaved to form a reinforced insulator. An external semiconductive layer was provided on the outside of the obtained reinforced insulator, and after cross-linking, the electrical performance was evaluated, and it was confirmed that the required electrical performance was obtained. In the figure, 13 is an air vent hole for venting air existing between the mold 10 and the transparent tube 7.

[0010]

As described above, according to the method for forming a power cable connecting portion of the present invention, the cable insulators of both cables to be connected are airtightly covered with the transparent tube, and the inner surface of the tube and the surface of the cable insulator are covered. After confirming that there is no foreign matter, a mold is placed on the outer side of the foreign matter, and resin is injected into the transparent tube to form a reinforced insulator excellent in electrical performance without foreign matter.

[Brief description of drawings]

1A and 1B are explanatory views showing a vertical section showing a procedure of a specific example of a forming method of the present invention.

2A and 2B are explanatory views showing a vertical cross section showing the procedure of another specific example of the forming method of the present invention.

FIG. 3 is an explanatory view showing a vertical section of an example of a conventional forming method.

[Explanation of symbols]

 1 Cable Insulator 2 Conductor Connection 3 Hard Transparent Tube 4 Sealing Tape 5 Packing 6 CCD Camera 7 Flexible Transparent Tube 8 Band 10 Mold 11 Resin Injection Tube 12 Vacuum Evacuation 13 Air Venting Hole

Claims (1)

[Claims] 1. A mold is installed over the insulators of both cables to be connected by including the conductor connection part of the cable, and the resin melted by heating is injected into the mold to be integrated with the cable insulator. In the method for forming a power cable connecting portion for forming a reinforced insulating body, before installing the mold, a transparent tube is airtightly provided over the insulators of both cables to be connected, and then a metal is provided on the outside thereof. A method for forming a power cable connecting part, which comprises setting a mold and injecting a heat-melted resin into the transparent tube to form a reinforcing insulator.