JPS58209875A - Reinforced insulating layer forming method for cable connector - 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 The present invention relates to a method of forming a reinforcing insulating layer of a cable connection portion using a split mold.

As is well known, in order to electrically insulate and reinforce the connection part of a rubber or plastic insulated cable, a semiconductive tape is wrapped around the cable conductor connection part and heated to form a conductor shielding layer. A reinforcing insulating layer is formed thereon. Conventionally, this reinforcing insulating layer was formed using a horizontal split mold consisting of an upper mold 11 and a lower mold 12, as shown in FIGS. 1 and 2.
The conductor connection portion 15 provided with a shielding layer is surrounded from above and below by a chive split mold 11.12, and a resin extruder 17 connected to the resin injection port 14 drilled in the upper mold 11 is injected into the mold 11.12. The reinforcing insulating layer 16 is formed by extruding and injecting resin into the
When a horizontal halved mold consisting of an upper mold 11 and a lower mold 12 is placed over the conductor connection portion 15 and resin is injected into the mold, the seam 13 of the mold is located on the horizontal side of the mold. Upper mold 1 to
The air in the upper mold 11 cannot escape to the outside, and even if a mold with multiple air vent holes is used in the upper mold 11, the molten viscosity of the injected resin is high, so the air cannot be sufficiently exhausted. The air remaining in the insulating layer 11 is gradually compressed by the injected resin, and this compressed air is eventually caught up in the extruded and injected resin, creating a large void inside the formed reinforcing insulating layer 16, which deteriorates the electrical characteristics of the connection part. There was a drawback that it decreased significantly.

The present invention has been made for the purpose of solving the above-mentioned drawbacks, and an embodiment of the present invention will be described below with reference to the drawings.The present invention connects both cable conductors to be connected with a compression sleeve,
After forming a conductor shielding layer by winding and heat-sealing semiconductor 1 (I-type tape), as shown in FIG. 14111 to surround the cable conductor connection part 5 so that at least one of them faces upward, and the pressure of the resin injected into the mold is applied to the joint 1+3 of the mold.
After tightening the molds with bolts so that there is a gap of 11 or less, connect the resin extruder 7 to the resin inlet 4 drilled in the mold 1, and then connect the split mold 1.2, pin and conductor connection part 5. A reinforcing insulating layer 6 is formed by extruding and injecting a resin such as polyethylene into the air defense between the two.

Next, to explain a specific example of the present invention, in 66, 'VO
The end of the V-cable is shaved into a pencil shape, the internal conductor is connected with a compression sleeve, a semiconductive tape is wound on top of it and heat fused to form a shielding layer, and then a chive split is placed on the conductor connection. Align the molds with the seams facing upwards and cover them, and use the pressure of the resin injected into the molds to tighten the bolts so that there is a gap of 05 openings and a gap of 2 holes at the mold alignment +13. A polyethylene resin containing a cross-linking agent was extruded and injected into the mold that was used as a comparative example, and a mold that was made by covering the conductor connection part with a chive split mold that was aligned laterally and tightening the bolts under the same conditions as above. After forming the insulating layer 6, the reinforcing insulating layer 6 was molded by pressurizing and heating it from the outside at 200°C and 10 kg/cJ for 3 hours.The reinforcing insulating layer according to the example of the present invention and the reinforcement according to the comparative example. The results of measuring the electrical properties of the insulating layer are shown in the table below.

According to the present invention, as described above, two or more multi-segmented molds are used, and the connecting portions 5 of the cable conductors are surrounded with at least one of the seams 3 facing upward, and the resin is filled in the molds. By forming the reinforcing insulating layer 6 by extrusion injection, the air inside the mold is completely extruded together with the resin that overflows outward from the gap between the joints 3 of the mold, so the remaining air strengthens the molding. There is no possibility that voids will be formed in the insulating layer 6, and as is clear from the above table, a reinforcing insulating layer with excellent electrical properties can be obtained. Note that the mold seam 3 is created by resin injection pressure.
If a gap of 1111 m or more is created, the pressure applied to the resin in the mold will decrease and there is a risk that voids will form inside. Therefore, in order to obtain fully satisfactory electrical characteristics, it is necessary to
1? It is desirable to bolt the mold so that there is a gap of #I or less.

[Brief explanation of drawings]

FIGS. 1 and 2 are explanatory views showing a conventional method for forming a mold for reinforcing insulating layers, and FIG. 3 is an explanatory view showing an embodiment of the reinforcing insulating layer forming method according to the present invention. 1: Mold 2: Mold 3: Mold alignment [14: Resin injection port 5 = conductor connection part 6: Reinforcement insulating layer q: @ fat extruder 5-

Claims (1)

[Claims] Two or more multi-segmented molds are placed over the table conductor connection portion provided with a shielding layer, with at least one of their joints facing upward, and the space between the mold and the cable conductor connection portion is A method for forming a reinforcing insulating layer for a cable connection part, the method comprising forming the reinforcing insulating layer at a cable connection part by injecting and filling the part with a resin.