JP4044180B2 - Prefabricated connection for CV cable - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a prefabricated connection portion for a CV cable applied to a terminal connection and an intermediate connection of a CV cable, and in particular, an adhesiveness between a cable insulator and a rubber mold stress cone by devising a shape of the end portion of the cable outer semiconductive layer. It is intended to improve.
[0002]
[Prior art]
The prefabricated joint consists of a rubber mold stress cone, an epoxy unit and a pressing device manufactured in advance at the factory. The rubber mold stress cone is inserted on the cable insulator and pressed against the epoxy unit and the cable insulator with the pressing device. A connection part is formed.
[0003]
In this way, the prefabricated connection portion can be configured by assembling the parts that are unitized, so there is an advantage that the working time can be shortened.
[0004]
Further, since the prefabricated connection portion is configured to hold the insulation by pressing the rubber mold stress cone against the epoxy unit and the CV cable insulator, the rubber mold stress cone is insulated from the epoxy unit and the CV cable. The adhesion at the interface with the body greatly affects the performance of the connection.
[0005]
[Problems to be solved by the invention]
From the actual state of the prefabricated connection part, the tip of the external semiconductive layer (hereinafter referred to as cable external guide) of the cable insulator into which the conventional rubber mold stress cone is inserted is newly added as shown in FIG. The cable guide was formed using a semiconductive tape for molding, and the rubber mold stress cone 16 was inserted so as to ride on the flat portion of the mold tape layer 12b. However, the molding process using the molding tape requires time, and there has been a strong demand for shortening the time.
[0006]
Also, as shown in FIG. 4, the cable outer guide end portion is cut into a taper shape, and the rubber mold stress cone end 16a is inserted on the cable outer guide via the tapered portion.
[0007]
Rubber mold stress cones are generally manufactured with a smaller inner diameter than the outer diameter of the cable insulator.
[0008]
For this reason, silicone oil is applied to the surface of the cable insulator and the inner surface of the rubber mold stress cone at the time of connection site assembly to facilitate insertion of the rubber mold stress cone into the cable.
[0009]
Almost all of the silicone oil is discharged to the outside upon insertion. However, as shown in FIG. 5, a silicone oil pool 21 is formed in the gap at the interface between the rubber mold stress cone 16 and the cable insulator 12.
[0010]
This oil sump is a cause of a decrease in insulation performance, particularly variation in initial insulation performance, and there has been a demand for improvement.
[0011]
The present invention has been made in view of such circumstances, and provides a prefabricated connection portion for a CV cable that reduces oil sump by the shape of the cable outer guide end and exhibits stable insulation performance for a long period of time. With the goal.
[0012]
[Means for Solving the Problems]
In view of the problems as described above, the present invention provides an epoxy unit disposed on the outer periphery of a conductor connecting pipe to which a cable conductor is connected, and a rubber mold stress cone is inserted between the cable insulator and the epoxy unit with a predetermined pressing force. In the prefabricated connection portion for CV cable, the end portion of the outer semiconductive layer of the cable is formed in the center by sequentially cutting the large-diameter first taper portion, smooth portion, and small-diameter second taper portion by mechanical cutting. The rubber mold stress cone is formed by two-stage cutting provided with the smooth portion having a predetermined length, and the rubber mold stress cone is inserted so that a rear end of the rubber mold stress cone is located at the position of the smooth portion. Is.
[0013]
Even if the stress cone is inserted into the cable insulator by applying silicone oil during assembly of the prefabricated connection part to the cable insulator and the inner surface of the stress cone, the stress cone and cable The oil sump formed at the interface between the outer conductor end and the cable insulator can be reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the prefabricated connection part for CV cables of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 8 shows an intermediate connection portion of a CV cable to which the present invention is applied. In the drawing, the insulator 12 of the CV cable 10 is peeled off for a predetermined length, the conductor 11 is exposed, and the counterpart cable conductor 11 is connected to the conductor connecting tube (compression sleeve) 13. The epoxy unit 14 in which the inner shielding metal fitting 15 is embedded corresponding to the central portion of the conductor connecting portion is disposed so as to surround the conductor connecting portion, and the inner surface of the inner shielding metal fitting 15 is arranged at the center of the outer periphery of the conductor connecting tube 13. It is made to fix to. Further, the rubber mold stress cone 16 inserted on the cable insulator 12 is brought into contact with the taper portions on both sides of the epoxy unit 14, and is further pressed against the epoxy unit 14 by the pressing metal 17 and the spring unit 18. The insulation characteristic is obtained by receiving a surface pressure of a certain level or more at the interface between the rubber mold stress cone 16 and the epoxy unit 14 or at the interface between the rubber mold stress cone 16 and the cable insulator 12.
[0016]
Reference numeral 19 denotes an intermediate junction box main body case.
[0017]
The roller which is a feature of the present invention is that the shape of the cable outer guide end portion is as shown in FIG. 1 in the prefabricated connection portion. In the embodiment of FIG. 1, the thickness of the first taper portion 12a ₁ of the cable outer conductor 12a is 1.0 mm, the length of the smooth portion 12a ₂ is 20 mm, and the thickness of the second taper portion 12a ₃ is 1.0 mm or less. It is formed by shaving. This two-stage cutting can be applied with machine cutting by an automatic externally-guided cutting machine.
[0018]
As shown in FIG. 6, silicone oil 20 is applied to the surface of the cable insulator 12 and the inner and outer surfaces of the rubber mold stress cone 16 at the time of on-site assembly, and the rubber mold stress cone 16 is inserted into the cable. .
[0019]
Since the inner diameter D of the rubber mold stress cone 16 is originally made smaller than the outer diameter D _{0 of the} cable insulator, most of the silicone oil is discharged outside when the stress cone is inserted. A small amount of silicone oil 20 is caught in the interface with the body 12. A surface pressure is applied to the interface, and the trace amount of silicone oil accumulates in the gap between the inner surface of the stress cone 16 and the end of the cable outer guide 12a as shown in FIG.
[0020]
As described above, since the shape of the cable guiding end of the present invention is cut in two steps and a smooth portion is provided in the center of the end portion, if the rear end of the rubber mold stress cone is inserted at the position of the smooth portion, the stress cone The gap between the cable and the cable insulator can be reduced, and the capacity of the silicone oil pool can be reduced. As a result, the silicone oil pool can be reduced.
[0021]
【The invention's effect】
As described above, according to the prefabricated connection portion for CV cable of the present invention, the shape of the cable outer guide end is cut in two steps and the smooth portion is provided in the center of the end portion. If the stress cone is inserted so as to be at the position of the part, the interface gap near the cable guiding end can be reduced, and the accumulation of silicone oil can be reduced.
[0022]
In addition, the shape of the cable guiding end can be formed accurately and efficiently because an automatic guiding machine can be applied.
[0023]
Furthermore, since it is not necessary to wind and mold a semiconductive tape for molding around the cable outer guide end, the connection portion forming time can be greatly shortened.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a state in which a rubber mold stress cone is inserted into a cable insulator relating to a prefabricated connection portion for a CV cable of the present invention.
FIG. 2 is an explanatory view showing an enlarged interface near the cable guiding end in FIG. 1;
FIG. 3 is an explanatory view showing a state where a rubber mold stress cone is inserted into a conventional cable insulator.
FIG. 4 is an explanatory view showing a state in which a rubber mold stress cone is inserted into a cable insulator according to another conventional method.
FIG. 5 is an explanatory diagram showing an enlarged interface near the cable guiding end in FIG. 4;
FIG. 6 is an explanatory view showing a state where a rubber mold stress cone is inserted into a cable.
FIG. 7 is an explanatory view simulating that a silicone oil bowl is formed at the interface between a rubber mold stress cone and a cable insulator.
FIG. 8 is a longitudinal sectional view of a prefabricated intermediate connection portion for a CV cable.
[Explanation of symbols]
10 Cable 11 Cable conductor 12 Cable insulator 12a Cable guide 14 Epoxy unit 16 Rubber mold stress cone 20 Silicone oil 21 Silicone oil pool

Claims (1)

An epoxy unit (14) is arranged on the outer periphery of the conductor connection pipe (13) to which the cable conductor (11) is connected, and a rubber mold stress cone (16) is provided between the cable insulator (12) and the epoxy unit (14). In the prefabricated connection for CV cable inserted with a pressing force of
The end portion of the outer semiconductive layer of the cable is formed by machining the first tapered portion (12a1) having a large diameter, the smooth portion (12a2), and the second tapered portion (12a3) having a small diameter in order to have a predetermined length in the center. The rubber mold stress cone (16) is formed in a two-stage shaving provided with the smooth portion (12a2) of the rubber mold so that the rear end of the rubber mold stress cone (16) is positioned at the position of the smooth portion (12a2). Prefabricated connection for CV cable, characterized by being inserted

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