JPS6177290A - Formation of connection for rubber/plastic cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of forming an intermediate connection portion of a rubber-containing plastic cable.

[Prior Art] Four methods are currently used to form connections for rubber/plastic cables of extra high voltage or higher.

1) Self-adhesive tape wrapping 2) Tape-wrapped mold 3) Injection mold 4) Pre-fabricated method [Problems to be solved] Of these, self-adhesive tape-wrapped 2) and pre-fabricated method 4) require ultra-high pressure. For voltages above +54 kV, the molding methods 2) and 3) are used. However, they have the following problems.

(1) It takes a lot of effort and time to carry out heating, crosslinking, and cooling for a long time under pressure.

(2) Heating, cooling, and pressurizing conditions also need to be made precise in consideration of the insulation performance of the connections, which requires a great deal of cost for the equipment and control system used.

(3) The connection cable must be heated, which may cause unnecessary damage to the cable. To prevent this, careful attention must be paid to prototype conditions, heat radiation at the ends, and the design and use of heating equipment.

(4) Additionally, a jointer with special education and training is generally required.

(5) Furthermore, in the case of tape-wrapped molds, it is necessary to use a dust-proof and moisture-proof tape winder (surrounded by a transparent box such as acrylic).

(6) In the case of injection molding, the resin must be injected on-site using an extruder. Further, the extruder is also troublesome because it has to extrude the equivalent of the reinforcing insulator in a short period of time, making it large in size.

[Means for Solving the Problems] This invention aims to solve the following two points, and as shown in FIG.
The cable near 0 is covered with a reinforcing insulator block 22 that has been formed in advance into the shape of the reinforcing insulator at the connection part or a shape similar to it, and the interface between it and the cable on the inside is ultrasonically welded. shall be.

[Example] In FIG. 1, 10 is the entire cable, and 11 is a conductor connection portion.

Reference numeral 12 denotes a cable insulator, and in this case, the end portion is cut into a stepped shape to facilitate ultrasonic welding. Reference numeral 14 designates an inner semiconducting layer of the cable, 16 an inner semiconducting layer of the connection portion, and 18 an outer semiconducting layer of the cable.

Since the vicinity of the conductor connection portion 11 has many irregularities, making ultrasonic welding difficult, a valley filling portion 20 is formed to flatten the surface. Note that this valley-filling portion 20 is formed using a heat-shrinkable tube, injection of molten resin, tape-wrapping mold, or the like.

The reinforcing insulator block 22 is formed in advance in a T-field, and is made of PE, XLPE, PP, EPR, or the like. This is, for example, a cylindrical body having the same thickness as the reinforcing insulator of the cable, and its inner surface is shaped so that the cable insulator 12 and the valley-filling portion 20 described in 2 are in close contact with each other. Further, it is divided into a plurality of parts by a plane including a central axis and a radius. Note that the mating surfaces can be of a mating type.

Furthermore, when the reinforcing insulator block 22 is molded, an external semiconductive layer 24 is simultaneously formed on its outer surface. However, since the part beyond the imaginary line 26 will be removed later, that part may be omitted.

The reinforcing insulator block 22 is placed over the cable lO, and the interface between them and the dividing surface of the block are ultrasonically welded.

Ultrasonic welding is carried out in accordance with conventionally known ultrasonic plastic welding, for example as follows (FIG. 2).

A vibrator 30 and a horn 32 are attached to a part of the ring 28. 34 ultrasonic oscillator. Also on the opposite side is the pedestal 36.
will be established. The ring 28 is split into two, and one side is attached to the hinge 2.
9, and by compressing the space between the other flanges 38 with a spring 40 (or a small pneumatic cylinder), pressure is applied to the welding surface. In this state, the ring 2 is run from end to end along one generatrix on the outer surface of the reinforcing insulator block 22.
Ultrasonic welding is carried out while moving the ring 8, then the ring 28 is slightly rotated as shown by the arrow 42 and ultrasonic welding is carried out in the same manner as above, and this is repeated to weld the entire surface.

After the ultrasonic welding is completed, the outside is scraped away from the imaginary line 26 in FIG. 1, and the outer semiconducting layer 24 is formed on the tapered surface.

[Other Embodiments 1 (1) The end of the cable insulator 12 may be shaped like a pencil instead of having a stepped shape. At that time, the inner surface of the reinforcing insulator block 22 is also shaped to be in close contact therewith.

(2) The valley filling portion 20 may be omitted.

(3) Both ends of the reinforcing insulator block 22 may be tapered from the beginning.

[Effects of the Invention] (1) Since cold welding is performed using ultrasonic welding, jointing can be performed instantly without requiring a long time for heating and cooling.

(2) Therefore, machines such as a heating molding device and a control device are not required, and assembly time and working time are significantly shortened.

(3) There is no need to provide a forming tape winding machine or extrusion machine on site.

(4) Cold welding eliminates the risk of damaging the cable.

(5) Since the reinforcing insulator block is controlled and manufactured in advance at the factory, the reliability of the connection performance is improved.

(6) Easily cope with problems such as insufficient power supply capacity and insufficient construction space at the installation site.

(7) Does not require a high level of skill.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the method of the present invention, and FIG. 2 is an explanatory diagram of ultrasonic welding. lO: cable ll: conductor connection part 12: cable insulator 20: valley filling part 22: reinforcing insulator block 30: vibrator 32: horn 34: ultrasonic oscillator

Claims (1)

[Claims] A reinforcing insulator block that has been shaped in advance to the shape of the reinforcing insulator at the connection part or a shape similar to that is placed over the cable near the conductor connection part or the valley filling part formed around it, and the cable inside A method for forming a connection part of a rubber/plastic cable, characterized by ultrasonically welding the interface with the rubber/plastic cable.