JPS61101989A - Connection of cv 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 Application Field] In recent years, an extrusion mold method has been used as a method for connecting ultra-high voltage CV cables.

There are two types of extrusion molding methods: 2) one in which extrusion molding and the subsequent pressure crosslinking are performed in separate molds, and 2) one in which the extrusion molding is performed in one mold.

The present invention relates to the connection method (2) performed using one mold.

[Prior art and its problems] (1) Case shown in Fig. 7 (#Opening/closing 58-126888)
:1O is a cable conductor connection part, 12 is a cable insulator.

14 is a mold, and the following outer box 16. It is composed of a molded a18° diaphragm 22. The outer box 16 is made of plastic or metal that can be subjected to high pressure and high temperature during crosslinking. X&
The keepsake 18 is made of plastic or metal that can withstand the pressure and temperature during extrusion molding, and is provided with a large number of through holes 20. Moreover, the inner surface shape is made almost the same as the shape of the reinforcing insulator. The diaphragm 22 is made of a stretchable material such as silicone rubber, and is shaped to fit tightly against the inner surface of the molded cylinder 18.

A resin 24 (polyethylene containing a crosslinking agent) for forming a reinforcing insulator is extruded into the diaphragm 22 .

In the next crosslinking step, pressurized medium 26 (
(e.g. gas) and simultaneously heated by suitable means. Pressure medium 26 passes through hole 20 and pressurizes resin 24 via diaphragm 22 .

- Problem: As the voltage class of the cable increases, the volume of the resin 24 increases, and the amount of expansion (expansion force) during crosslinking also increases. However, in this case, since the molded tube 18 presses down on the outside, the cable insulator 12 is deformed, making it impossible to obtain a good connection.

(2) In the case of Figures 8 and 9 (Japanese Patent Laid-Open No. 58-22327
9): As shown in FIG. 8 which shows only the mold 14, the molding cylinder 2
8, attach a rod 30 to each part, and mold 14.
The molding cylinder 28 can be opened and closed from the outside. Through hole 20
is not provided.

With the molding tube 28 closed, the resin 24 is extruded into the diaphragm 22.

In the next crosslinking step, the molding tube 28 is opened.

For example, heated silicone oil is used as the pressurizing medium 26 and is circulated through the mold 14 to pressurize and heat the resin 24 via the diaphragm 22 .

In this case, the expansion force of the resin 24 can escape to the outside.

- The problem: The structure of the mold 14 becomes complicated, including the airtight structure of the part where the rod 30 penetrates the outer box 16.

[Object of the Invention] To use a mold 14 having a simple structure and to be able to release the expansion force of the resin 24 during crosslinking.

[Means for solving the problem] Mainly as shown in FIGS. 1 and 2, (1) A molding cylinder 32 whose inner surface shape is approximately equal to the shape of the reinforcing insulator is provided in the mold die 14. In addition, all or part of the molding cylinder 32 is constituted by an openable and closable portion 36 with an axial split in at least one place; (2) A means 40 for closing the openable and closable portion 36 is provided. To leave.

(3) During extrusion molding, the openable/closable portion 36 is kept closed by the closing means 40, but during thermal crosslinking, the closing means 40 has a closing ability due to the heat applied thereto or the thermal expansion force of the resin. to open the openable/closable part 36.

It is characterized by

[Example] In FIG. 1, the mold 14 and its outer box 16 are the same as in the conventional case.

The molded cylinder 32 includes a fixed part 34 and an openable/closable part 3 as described below.
6, and its inner surface shape is made almost the same as the shape of the reinforcing insulator.

[The old constant part 34 regulates the shape of both end portions of the reinforcing insulator. This part remains fixed and does not open.

The openable/closable portion 36 is a cylindrical body having tapered ends, with axial divisions provided at, for example, two locations, and is made of, for example, iron, aluminum, or the like.

As mentioned above, the openable portion 36 remains closed during molding of the resin 24.

For this purpose, for example, flanges 38 are provided on the split parts of the openable/closable part 36 and are connected by closing means 40 .

This closing means 40 is the most important part of the present invention,
Select the material, shape, and dimensions appropriately as described above.

(1) During extrusion molding, the openable and closable portion 36 is kept closed depending on the heat and pressure at that time. (2) During thermal crosslinking, the heat and resin applied to it are kept closed. It must be ensured that the force due to the thermal expansion of the material causes it to lose its ability to close.

The point of "losing the ability to close" in (2) above can be specifically described as follows.

1) The closure means 40 is made of a resin material that melts at the heating temperature during crosslinking, such as polyethylene or polypropylene.

2) A resin material that causes stress reduction due to heating during crosslinking and expands or breaks due to the thermal expansion force of the resin 24;
For example, it is made of polycarbonate, nylon, etc.

3) The closing means 40 is made of porcelain (ceramics, porous ceramics, etc.), metal, glass, etc., and its shape and dimensions are appropriate so that it will expand or break due to the thermal expansion force of the resin 24. Make it.

4) A shape memory alloy is used for the closing means, which shrinks at the temperature during extrusion, expands with the heat during heat crosslinking, and loses its closing ability.

Further, the specific configuration is, for example, as follows.

1) As shown in FIG. 3, a port 42 and a nut 44 are used as the closure means 40, and one or both of them are made of the materials described above.

2) As shown in Fig. 4 Ca) (b) (7), a pin 46 and a shear via 48 are used, and one or both of them is made of the above-mentioned materials. Note that (b) is (a
) as seen from the right side.

[Other Embodiments] In some cases, only one split is provided in the openable/closable portion 36 (FIG. 5).

Further, the openable/closable portion 36 may be divided into four parts as shown in FIG. 6, or may be divided into more parts.

[Effects of the Invention] During extrusion molding, the closing means 40 keeps the openable/closable portion 36 closed, but during heat crosslinking, the closing means 40 closes due to the heat applied thereto or the thermal expansion force of the resin. , the part 36 that has lost its ability to close and can be opened and closed.
1, the force generated when the resin 24 expands can be easily released, and the cable insulator 12 will not be deformed.

Furthermore, the structure of the mold 14 does not become complicated.

[Brief explanation of the drawing]

1 to 6 are related to the present invention. FIG. 1 is an explanatory diagram of an embodiment, and FIG. 2 shows a cross section taken along line II-II. FIG. 3 is an explanatory diagram of the closing means 40, and FIG. 4(a) is an explanatory diagram of different examples of the closing means 40.
A side view of it seen from the right side is shown in (b). 5 and 6 are explanatory diagrams of different examples of the openable/closable portion 36, FIG. 7 is an explanatory diagram of a prior art, and FIG. 8 is an explanatory diagram of a mold 14 used in another prior art. An explanatory diagram of the connection method using the is shown in FIG.

Claims (1)

[Scope of Claim] A method for connecting a CV cable in which a resin for forming a reinforcing insulator is extruded into a mold, and the resin is then cross-linked by heating. A molding cylinder having substantially the same shape is provided, and all or part of the molding cylinder is composed of an openable and closable portion with an axial split in at least one place, and a means for closing the openable and closable portion is provided. During extrusion molding, the closing means maintains the openable and closable portion in a closed state; however, during thermal crosslinking, the closing ability of the closing means is reduced due to the heat applied thereto or the thermal expansion force of the resin. lost,
A method for connecting a CV cable, characterized in that the openable/closable portion is opened.