JP2822086B2 - Connection method of rubber / plastic power cable - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for connecting a rubber / plastic power cable to a mold, and more particularly to a connection method using a pre-molded insulator.

[Prior Art] The following technique has been disclosed as a method of connecting a rubber / plastic power cable using a pre-molded insulator (see Japanese Patent Application Laid-Open No. 60-246577).

That is, as shown in FIGS. 2a to 2c, the inner surface is substantially the same as the shape of the cable in the cable conductor connection portion 12 and the vicinity thereof, the outer surface has the same shape as the outer shape of the reinforcing insulator, and is not divided into two. A block 20 made of cross-linked polyethylene is prepared, and is mounted on the cable core 10.

Here, 14 is an internal semiconductive layer, 16 is a cable insulator, and 18 is a cable shielding layer.

 The block 20 is pressed on the heat shrink tube 22.

 A mold 24 for cross-linking is placed thereon.

In the manner described above, the high-temperature and high-pressure liquid medium 26 is introduced into the mold 24, and the block 20 is heated and cross-linked.

 Thereafter, the temperature of the medium 26 is lowered and cooled.

[Problems to be Solved by the Invention] The halved block 20 must be uncrosslinked in order to fuse the divided surfaces, and therefore, after being mounted on the cable, it is necessary to crosslink the entirety. .

[Means for Solving the Problems] As shown in FIGS. 1a to 1g, (1) the outer shape is the same as the outer shape of the reinforcing insulator at the cable connection portion, the inner shape is cylindrical, and the outer half is A prefabricated heat-shrinkable reinforced insulator 30 made of cross-linked polyethylene on which the conductive layer 32 is formed is manufactured in advance. (2) The inner surface shape is the same as the shape of the cable core connection portion 15 and its vicinity, The outer surface shape is a cylindrical shape that is equal to or slightly larger than the outer shape of the cable insulator, and a two-part, polyethylene block 34 containing a cross-linking agent is also manufactured in advance. Feed it on the cable, connect the cable core, and then
(4) moving the heat-shrinkable reinforcing insulator 30 thereon and heat-shrinking it; (5) cross-linking the cross-linking agent-containing polyethylene block 34; It is characterized by.

[Operation] (1) A prefabricated heat-shrinkable reinforcement made of cross-linked polyethylene having the same outer shape as the outer shape of the reinforcing insulator at the cable connection portion, the inner shape being cylindrical, and the outer semiconductive layer 32 being formed. Since the insulator 30 is used, the inner diameter can be made larger than the outer diameter of the cable (including the anticorrosion layer).

Therefore, as described above, it is possible to feed the cable core, connect the cable core, and then return the cable core to a predetermined position and contract it.

(2) Further, since all of the connecting portion reinforcing insulators are manufactured in advance, the on-site forming process of the reinforcing insulators is not required, and connection by a so-called one-process method can be performed.

(3) The heat-shrinkable reinforcing insulator 30 and the cable core 10 are integrally fused by the crosslinking of the polyethylene block 34 containing the crosslinking agent.

[Examples] (FIGS. 1a to 1g) The operation steps will be described in order.

(1) First, a prefabricated heat-shrinkable reinforcing insulator 30 is manufactured in a factory in advance (FIG. 1a).

The outer shape is the same as the outer shape of the reinforcing insulator at the cable connection portion, and the inner shape is cylindrical. The inner diameter is larger than the outer diameter of the cable so that it can be fed onto the cable before connecting the cable core as described later. Made of crosslinked polyethylene.

 Further, an external semiconductive layer 32 is formed.

Note that reference numeral 33 denotes a border portion, which is not directly related to the present invention.

(2) A polyethylene block 34 containing a crosslinking agent (FIG. 1b) described below is also manufactured in advance.

This is because the inner surface shape is the same as the shape of the cable core connection portion 15 and the vicinity thereof, the outer surface shape is a cylindrical shape equal to or slightly larger than the outer diameter of the cable insulator, and is divided into two (see FIG. 35 is the dividing plane).

For convenience of description, a portion from the conductor connection portion 12 to the pencilling portion is referred to as a cable core connection portion 15.

(3) The heat-shrinkable reinforcing insulator 30 is fed onto the cable, and the cable conductor crimping, pencilling,
The processing on the inner semiconductive layer 14 is performed to connect the cable core 10.

(4) After connecting the cable cores, cover the cable core connection portions 15 with the polyethylene block 34 (FIG. 1d).

Then, hold both ends with the holding ring 36,
Make sure it doesn't come off (because it is split in two).

Then, the heat-shrinkable reinforcing insulator 30 is moved to a predetermined position (FIG. 1e).

(5) The heat-shrinkable reinforcing insulator 30 is shrunk by heating. At that time, as shown in FIG.
34 is melted and tightened by the contraction force of the heat-shrinkable reinforcing insulator 30, and air or the like at the interface is pushed out to both ends and contracted toward both ends.

When the vicinity of the center of the heat-shrinkable reinforcing insulator 30 is shrunk by about 1/3 of the entire length, the holding ring 36 is removed.

When the shrinkage is completed over the entire length, it is cooled, and the outer semiconductive layer 32 of the heat-shrinkable reinforced insulator 30 and the outer conductive semiconductive layer 18 of the cable core are crosslinked with a semiconductive tape for crosslinking or a semiconductive shrinkable tube 37 for crosslinking, Connect (Fig. 1g).

(6) A bridging mold 38 is assembled outside the heat-shrinkable reinforcing insulator 30 (FIG. 1g).

A deformation prevention pillow 42 (for example, a rubber bag filled with high-viscosity oil or nitrogen gas) is provided between the end fitting 40 of the mold 38 and the cable core 10, and the vicinity of the mold is provided. Avoid distortion in the cable core.

(7) The inside of the mold is heated under pressure to crosslink the uncrosslinked polyethylene block 34, semiconductive tape 37, and the like.

[Effects of the Invention] (1) Since a heat-shrinkable reinforcing insulator is used, it can be fed onto a cable, connected to a cable core, and then contracted.

(2) A mold for forming the reinforcing insulator is not required,
Since the assembly and disassembly of the mold need only be performed once for the cross-linking mold, the working time is reduced.

(3) It is not necessary to form a stress cone after cross-linking, and the external semiconductive layer and the rim of the reinforcing insulator can be manufactured in a factory in advance and the performance can be checked in advance, thereby improving reliability.

(4) Since the prefabricated block containing the cross-linking agent constituting the reinforcing insulator is relatively thin, the cross-linking after assembling on the cable is completed in a short time.

(5) The heat-shrinkable reinforcing insulator and the cable core are fused together via the polyethylene block which has been subsequently cross-linked by heating.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings are all related to the embodiment of the present invention, FIG. 1a is an explanatory view of a heat-shrinkable reinforcing insulator 30 to be used, FIG. 1b is an explanatory view of a polyethylene block 34 to be used, FIG. FIG. 1c is a sectional view taken along the line CC of FIG. 1b. FIGS. 1d, 1e, 1f, and 1g are explanatory views showing the connection method in the order of steps, FIG. 2c is an explanatory view of the prior art, and FIG. 2a is an explanation of an uncrosslinked polyethylene block used therein. FIG. 2B is a sectional view taken along line BB of FIG. 2A. 10: Cable core 15: Cable core connection 18: External semiconductive layer 20: Uncrosslinked polyethylene block 30: Heat-shrinkable reinforced insulator 32: External semiconductive layer, 33: Edge cutout 34: Uncrosslinked polyethylene block 36: Holding Ring 37: Semiconductive tape or shrink tubing 38: Mold for crosslinking, 42: Pillow to prevent deformation

Continuation of front page (72) Inventor Isao Kaji 1-5-1, Kiba, Koto-ku, Tokyo Fujikura Electric Wire Co., Ltd. (56) References JP-A-50-53892 (JP, A) JP-A-55-146886 ( JP, A) JP-A-56-57272 (JP, A) JP-A-56-98315 (JP, A) JP-A-58-126688 (JP, A) JP-A-62-60414 (JP, A) JP-A-63-18915 (JP, A) JP-A-64-16213 (JP, A) JP-A-3-52506 (JP, A) JP-B-63-48154 (JP, B2) (58) Fields investigated (Int) .Cl. ⁶ , DB name) H02G 1/14-1/16 H02G 15/00-15/196

Claims (1)

(57) [Claims] A step of preparing a heat-shrinkable reinforcing insulator having the same outer shape as the outer shape of the reinforcing insulator, the inner shape being cylindrical, and made of crosslinked polyethylene in advance; The same as the shape of the part and its vicinity, the outer surface shape is a cylindrical shape equal to or slightly larger than the outer shape of the cable insulator, and a two-part, cross-linking agent-containing polyethylene block is previously produced; Feeding the reinforcing insulator onto the cable, connecting the cable core, then covering the cable core connecting portion with the polyethylene block, and moving the heat-shrinkable reinforcing insulator to a predetermined position; The heat-shrinkable reinforcing insulator is heated and shrunk to hold the polyethylene block, and the outer semiconductive layer of the heat-shrinkable reinforcing insulator and the outer semiconductive layer of the cable core. And a step of assembling a cross-linking mold outside the heat-shrinkable reinforcing insulator; and a step of pressurizing and heating the inside of the cross-linking mold to cross-link the cross-linking agent-containing polyethylene block. A method for connecting a rubber / plastic power cable, including: