JPH02155182A - Formation of insulation connecting part for power 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] The present invention relates to a method for forming an insulated connection part (IJ) of a rubber/plastic electric cable, and particularly to the formation of an edge cut part.

[About insulated connections] An example is shown in Figure f53.

10 is a conductor connection part; 12 is a cable insulation layer; 14 is a cable outer semiconducting layer; 16 is a reinforcing insulating layer.

Reference numeral 18 designates an inner semiconductive layer of the edge cut portion provided directly on the reinforcing insulating layer 16, 20 indicates an edge cut portion insulating layer, and 22 indicates an outer semiconductive layer of the edge cut portion provided on the edge cut portion insulating layer 20.

[Prior Art and Problems] The following methods are available for manufacturing the above-mentioned insulated connection portion by batch molding.

That is, (1) the reinforcing insulating layer 16 is made of uncrosslinked PE or the like, (2) the inner semiconducting layer 18 is made of a shrunk semiconductive heat shrink tube, and (3) the edge insulating layer 20 is made of uncrosslinked insulating tape, (4) the outer semiconductive layer 22 is made of a shrunk semiconductive heat shrink tube, and (5) - lump molding is performed. be.

・Length Ω plate plate Δ: As shown in FIG. 4, the end portion 19 (inner electrode portion) of the inner semiconductive layer 18 falls in the direction of the conductor, reducing the electrical performance of the connection portion.

[Prior art that solved the above problems] It has been proposed to construct the inner semiconductive layer 18 using a semiconductive partially heat-shrinkable tube 180 described below (see Japanese Patent Application No. 140418/1982).

[11 Regarding the semiconductive partial heat shrink tube 180: As shown in Fig. ff15, the thick portion 26 and the tapered portion 2
8 and a thin portion 30, and the whole is made of a polyolefin material such as semiconductive crosslinked PE.

The thick portion 26 and the tapered portion 28 are made of heat shrink tubing.

In the thin portion 30, only the tip portion 32 is made of a non-shrinkable (or hardly shrinkable) tube, and the portion 34 is heat-shrinkable.

Note that the entire thin portion 30 may be non-shrinkable (or hardly shrinkable).

The inner diameter a of the thin portion 30 is made equal to the outer diameter b (FIG. 3) of the reinforcing insulating layer 16.

[2] How to use the partial heat shrink tube 180: (1) As shown in Fig. 6a, the above partial heat shrink tube 180 is placed on the reinforcing insulation 516 (outer diameter b) formed by extrusion or tape wrapping. Installing.

After determining the position of the tip portion 32, that is, the inner electrode, the remaining portion is heated and shrunk.

(2) Next, as shown in Fig. 6b, the edge-cut insulating layer 20 is wound up with uncrosslinked PE tape, the outside of which is covered with a semiconductive heat shrinkable tube 220, and the outside semiconductive tube is heated and shrunk. Layer 22 is formed.

(3) Then, the reinforcing insulating layer 16, the inner semiconducting layer 18,
Edge cutting portion insulating layer 2.0. The entire outer semiconductive layer 22 is molded all at once, and the state shown in FIG. 3 is completed.

(4) - Even if the reinforcing insulating layer 16 is softened by heating during bulk molding, the tip portion 32 of the semiconductive partial heat-shrinkable tube 180 does not shrink or hardly shrinks.
The drop as shown in Figure 54 does not occur.

[Problems to be Solved by the Invention] As shown in FIG. 7, the outer diameter C of the cable sheath 15 may be larger than the outer diameter C of the reinforcing insulating layer 16.

When forming the reinforcing insulation layer 16 (by extrusion molding, etc.), the partial heat shrink tube 180 is attached to the cable sheath 15.
You need to move it up.

However, as mentioned above, the partial heat shrink tube 180
The inner diameter a of 32 is equal to the outer diameter of the reinforcing insulating layer 16 (smaller than the outer diameter C of the cable sheath 15).

Therefore, it cannot be moved onto the cable sheath 15.

[Object of the Invention] The inner semiconductive layer 18 of the edge cut portion is constructed using a heat-shrinkable tube, but as shown in FIG. ) does not fall in the direction of the conductor;

It can be applied even when the outer diameter of the reinforcing insulating layer is larger than that of the reinforcing insulating layer.

[Means to solve the problem] t51a-Figure 2b.

Only the tip portion 42 of the IJ shrink tube 182 constituting the inner semiconductive layer 18 of the edge cut portion is made to have a shrinkage residual rate of 0% when it is shrunk until it comes into close contact with the reinforcing insulating layer 16.

[Description] [1] Regarding the IJ contraction tube 182: It is shown in FIG. 1a.

Made entirely of semi-conductive heat shrink tubing.

Its body 40 is made of conventional heat shrink tubing.

As described above, when the tip portion 42 is contracted until it comes into close contact with the reinforcing insulating layer 16, the residual shrinkage rate becomes 0% (it does not shrink any more).

The inner diameter d of the tip portion 42 and the inner diameter e of the main body 40 are both larger than the outer diameter C of the cable sheath 15.

[2] How to make IJ contraction tube 182 = (1) Main body 4
0 is made in a known manner, for example by a stretched semiconducting polyolefin tape (FIG. 1b).

(2) Separately from the main body 40, the tip portion 42 is molded from unstretched semiconductive polyolefin and machined into a ring-shaped piece whose inner diameter is equal to the outer diameter of the reinforcing insulating layer 16. figure).

(3) As shown in FIG. 1c, using a mandrel 44, the main body 40 and the tip 42 are molded and fused together.

Make it one.

The outer diameter of the small diameter portion 46 of the mandrel 44 used at this time is:
The inner diameter of the large diameter portion 48 should be equal to the inner diameter of the distal end portion 42, but larger than the outer diameter C of the cable sheath 15.

(4) As shown in the lid diagram, the diameter of the distal end portion 42 is expanded by a known method to make its inner diameter d larger than the outer diameter C of the cable sheath 15.

As described above, the IJ shrink tube 1 shown in FIG. 1a is
Make 82.

[3] Formation of the inner semiconductive layer 8: (1) As described above, since the inner diameter of the IJ shrink tube 182 is larger than the outer diameter C of the cable sheath 15, when forming the reinforcing insulating layer 16, You can move it to

After forming the reinforcing insulating layer 16, as shown in FIG. 2a, the IJ shrink tube 182 is moved onto the reinforcing insulating layer R16.

(2) Heat and shrink the entire IJ shrink tube 182 (Figure 2b).

At this time, the tip portion 42 also contracts until it comes into close contact with the reinforcing insulating layer 16. .

(3) After that, as in the conventional case, the edge cutting part insulating layer 2
0 and an outer semiconducting layer 22 are formed and molded.

At this time, since the remaining shrinkage rate of the tip portion 42 is 0% (it does not shrink further), it does not fall into the reinforcing insulating layer 16.

[Effects of the invention l Inner semiconducting layer of edge cutting portion I constituting the inner semiconducting layer 18
J shrink tube inner semi-conductive W! Only the tip portion 42 of the cable sheath 182 is designed so that when it is shrunk until it comes into close contact with the reinforcing insulating layer 16, the remaining shrinkage rate is 0%. Even if the outer diameter of the insulating layer is larger than that of the insulating layer, it is possible to create a stable molded insulated connection without causing the internal electrodes of the edge-cut insulating layer to drop by using the batch molding method using a heat-shrinkable tube.

[Brief explanation of the drawing]

Figures 1a to 2b relate to an embodiment of the present invention, Figure 1a is an explanatory diagram of the IJ shrink tube 182 used, and Figures 1b to 1d sequentially show a method for manufacturing the IJ shrink tube 182. An explanatory diagram. Figures 2a and 52b are explanatory diagrams sequentially showing how the IJ shrink tube 182 is used, and Figure 3 is a general explanatory diagram of the insulated connection part. Figure 4 and the following are related to the prior art. Figure 4 is an explanatory diagram of the problem, Figure 5 is an explanatory diagram of the partial heat shrink tube 180 used, and Figures 6a and 6b are 1 partial An explanatory diagram showing the order of the IJ shadow forming process using the heat shrink tube 180, and FIG. 7 is an explanatory diagram of conventional problems. lO: Conductor connection part 12: Cable insulating layer 14: Cable outer semiconducting layer 16: Reinforcement insulating layer 18: Inner semiconducting layer of edge cutting part 20: Edge cutting part insulating layer 22: Outer semiconducting layer of edge cutting part 32: Tip part 40: Main body 42: Tip portion 44: Mandrel 46: Small diameter portion 48 Two large diameter portions 180: Semiconductive partial heat shrink tube 182: IJ shrink tube 220: Semi conductive heat shrink tube

Claims (1)

[Scope of Claims] When forming an insulating connection portion by providing an inner semiconductive layer of the edge cut portion, an edge cut portion insulating layer, and an outer semiconductive layer of the edge cut portion on the reinforcing insulating layer, the inner side of the edge cut portion In a method for forming a power cable insulated connection part in which a semiconductive layer is formed using a heat-shrinkable tube, only the tip of the heat-shrinkable tube forming the inner semiconductive layer of the edge cut portion is placed on the reinforcing insulating layer. A method for forming an insulated connection part of a power cable in which the remaining shrinkage rate is 0% when it is shrunk until it is tightly bonded.