JPH09275628A - Connection of plastic power cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the direct exposure work time and improve the adhesion between a cable core and a mold rubber insulator, by mounting a circular and rigid gyps astride the large-diameter part of the mold rubber insulator and the small diameter part of the end, and engaging the inside diameter of the gyps and both or either of the large diameter part and the small diameter part with each other. SOLUTION: Gyps 5 of circular and rigid material is mounted coaxially with a cable core 1 astride a large diameter part 41 of a mold rubber insulator 4 and a small diameter part 42 of the end. Then, both or either of circular projections 51 and 52 provided at the inside periphery of the gyps 5 is engaged with the large diameter part 41 or small diameter part of the mold rubber insulator 4. This prevents the gyps 5 from deviating in the axial direction of the mold rubber insulator 4. As a result, it becomes possible to lighten the degree of necessity to the rectilinearity of the cable, and the time required for the direct exposure work is shortened, and the adhesion between the cable core and the mold rubber insulator is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug-type connection part of a plastic power cable such as a CV cable.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view of a main part of an example of a conventional plug-in type connecting portion of a plastic power cable. The inner diameter is designed to be smaller than the outer diameter of the cable core 1, and a diameter-expanding jig is inserted into the inner diameter of the molded rubber insulator 4 formed by integrally molding the manufactured insulating rubber portion 4a and the semiconductive rubber portion 4b. The diameter of the molded rubber insulator 4 is inserted into one side of the cable to be connected in advance before connecting the cable conductor, and after the cable conductor is connected, the molded rubber insulator 4 is returned to the connecting portion 2 and expanded. By pulling out the diameter jig, the molded rubber insulator 4 is contracted by its elastic force,
A connecting portion reinforcing insulating portion is formed in close contact with the cable core 1.

[0003]

In the formation of the above-mentioned connecting portion, if the cable core is bent when the molded rubber insulator is inserted, a gap is created at the interface between the inserted molded rubber insulator and the cable core. Insulation performance of parts may be reduced. Therefore, a so-called straight-out work is required to straighten the cable core before inserting the molded rubber insulator. However, this straight-out work needs to be performed while strictly controlling the linearity, and there is a problem that this work takes a long time.

Further, the above-mentioned connecting portion holds the surface pressure at the interface with the cable core by the self-shrinking force of the molded rubber insulator, but this surface pressure changes due to aging. For this reason, when the cable core is subjected to thermo-mechanical stress or mechanical external force during long-term use, the cable core bends, and the required surface pressure cannot be obtained, resulting in voids at the interface between the cable core and the molded rubber insulator. There is a problem that insulation performance is degraded.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, reduces the degree of necessity for the linearity of the cable core, and shortens the time required for straight-out work, and at the same time, the cable core and the molded rubber insulator. The present invention provides a connection portion for a plastic power cable that achieves improved adhesion and stability, and its first feature is that it has a cylindrical shape across the large diameter portion and the small end diameter portion of the molded rubber insulator. And a connection portion of a plastic power cable, in which a cast of a highly rigid material is mounted, and the inner peripheral portion of the cast and the large diameter portion and / or the small diameter portion have a fitting portion. It is in.

A second feature of the present invention is to mount an annular cushion material on the cable core outside the small diameter portion of the end portion of the molded rubber insulator, and to attach the annular cushion material and the end of the molded rubber insulator. A cylindrical and high-rigidity material is mounted over the small-diameter portion, and the inner peripheral portion of the cast and the small-diameter end portion of the molded rubber insulator have a fitting portion. At the connection of the plastic power cable.

Further, a third feature of the present invention is to cover the molded rubber insulator, mount a cast of a cylindrical and highly rigid material which is divided into two in the lengthwise direction, and connect the joint in the lengthwise direction. In addition to being mechanically connected, the inner peripheral portion of the cast and the large diameter portion and / or the small diameter portion of the molded rubber insulator have a fitting portion, and further, an extension portion in the length direction is provided. It is located at the connection part of the plastic power cable which is located on the cable sheath and is waterproofed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a longitudinal sectional view of a main part of an embodiment of a first feature of the present invention. In the drawing, the same reference numerals as those in FIG. 4 indicate the same parts. In the drawing, reference numeral 4 denotes a molded rubber insulator, which is located on the conductor connecting portion 2 by a known means, and is attached by its elastic force so that its inner peripheral surface is in close contact with the outer peripheral surface of the cable core 1. A cylindrical shape that extends over a position close to the end of the large diameter portion 41 of the molded rubber insulator 4 and across the small diameter portion 42 of the end,
A cast 5 made of a highly rigid material is mounted concentrically with the cable core 1. As the material having high rigidity, for example, a metal material or a synthetic resin such as FRP, ABS, PP is used.

Annular projections 51 and 52 are provided on the inner peripheral portions of both end edges of the cylindrical cast 5, and the annular projections 51 and 5 are provided.
Both or one of the two is fitted into the large-diameter portion 41 and / or the small-diameter portion of the molded rubber insulator 4.
As a result, the cast 5 is prevented from shifting in the axial direction of the molded rubber insulator 4, and the large diameter portion 41 and the small diameter portion 42 maintain the concentric shape.

The fitting between the annular projection provided on the inner peripheral portion of the end of the cast 5 and the molded rubber insulator 4 is, for example, as shown in FIG.
As shown in (b), the large diameter portion 4 of the molded rubber insulator 4
1. An annular groove 6 having inclined surfaces on both sides is formed at a position close to the end of 1 and an annular projection 5 having a shape that engages with the annular groove 6.
By fitting 1 into the annular groove 6, the cast 5 is fixed to the molded rubber insulator 4. At this time, the relativity of the inner and outer diameters of the fitting portion of the molded rubber insulator 4 and the cast 5 is
The mold rubber insulator 4 is selected so as to receive a compressive force after the cast 5 is mounted. Mold rubber insulator 4
In order to facilitate the mounting of the cast 5 on the molded rubber insulator 4, it is preferable to provide inclined surfaces 4a at the ends of the large diameter portion and the small diameter portion of the molded rubber insulator 4. Incidentally, it is needless to say that the same effect can be obtained by providing an annular groove on the cast 5 side and an annular protrusion on the molded rubber insulator 4 side for fitting in the above.

As described above, the cable core 1 is slightly bent by mounting the cast 5 made of a highly rigid material across the large diameter portion 41 and the small end diameter portion 42 of the molded rubber insulator 4. Even in this case, the vicinity of the end of the molded rubber insulator 4 is held linearly at least by the rigidity of the cast 5, and between the casts 5 at both ends of the molded rubber insulator 4,
Mold rubber insulator 4 along the bend of cable core 1
Is deformed or the elastic force of the molded rubber insulator 4 causes the cable core 1 to be linear, so that there is no gap at the interface between the cable core 1 and the molded rubber insulator 4, and the interface surface The pressure does not drop significantly.

FIG. 2 is a vertical cross-sectional view of an essential part of the embodiment of the second feature of the present invention. In the drawings, the same reference numerals as those in FIG. 1 represent the same parts. In the present embodiment, an annular cushion material is provided on the cable core 1 on the outer side in the length direction of the molded rubber insulator 4 which is mounted on the outer side of the conductor connecting portion 2 with the inner peripheral surface being in close contact with the outer peripheral surface of the cable core 1. Wear 8. Then, a cast 5 made of a material having a high rigidity is mounted concentrically with the cable core 1 straddling the annular cushion member 8 and the small end portion 42 of the molded rubber insulator 4.

Annular projections 51 and 52 are provided on the inner peripheral portions of both end edges of the cylindrical cast 5 and one of the annular projections 51 is formed.
1 in the small diameter portion 42 of the molded rubber insulator 4 shown in FIG.
The structure is similar to that of (B), and the other one of the annular protrusions 52 is positioned on the annular cushion member 8. This prevents the cast 5 from shifting in the axial direction of the molded rubber insulator 4 and holds the small diameter portion 42 and the cable core 1 in a concentric shape. Further, by mounting the annular cushion member 8 on the cable core 1 and locating the one annular projection 52 of the cast 5 on this, the radial expansion and contraction of the cable core 1 are absorbed, and the cable core 1 is cast. 5 prevents mechanical damage. In the above, as described above, an annular groove may be provided on the side of the cast 5 and an annular protrusion that fits into the small diameter portion 42 of the molded rubber insulator 4 may be provided and fitted together.

With this structure, even when the cable core 1 is slightly bent, the mold insulator 4 is deformed along the bend of the cable core 1 between the casts 5 at both ends of the mold rubber insulator 4. Or the elastic force of the mold insulator 4 causes the cable core 1 to be linear, so that no void is formed at the interface between the cable core 1 and the mold insulator 4, and the surface pressure at the interface is greatly reduced. Never. At this time, the relativity of the inner and outer diameters of the fitting portion between the mold insulator 4 and the cast 5 is determined by the cast 5
The mold rubber insulator 4 is selected so as to receive a compressive force after the mounting. Further, in order to facilitate the mounting of the cast 5 on the small-diameter portion 42 of the molded rubber insulator 4, the inclined surface 4a is provided at the end of the small-diameter portion 42 as described above.

FIG. 3 is a vertical cross-sectional view of an essential part of a third embodiment of the present invention. In the drawings, the same reference numerals as those in FIG. 1 represent the same parts. In the present embodiment, the cylindrical outer surface of the conductor connecting portion 2 is covered with the molded rubber insulator 4 having the inner peripheral surface closely attached to the outer peripheral surface of the cable core 1 and is divided into two in the longitudinal direction. And the Gibbs 5 made of highly rigid material is attached. The joints in the lengthwise direction of the bifurcated cast 5 are mechanically connected and integrated by fastening the joint flanges 5a provided at the ends with bolts or the like. Further, two annular projections 51 and 52 are provided on the inner peripheral portion of the cast 5, one of which is a large diameter portion 41 of the molded rubber insulator 4 and the other of which is a small diameter portion 42.
Are fitted by the structure shown in FIG. Further, the cast 5 has an extension portion 53 in the length direction, the end portion 53 of the extension portion 53 is located on the cable sheath 3, and is subjected to a waterproof treatment 7 by winding a waterproof tape or the like. In the above, an annular groove may be provided on the cast 5 side and an annular protrusion fitted on the molded rubber insulator 4 side may be provided so that they are fitted to each other. This structure integrates the conventional outer case that covers the molded rubber insulator and mechanically protects it with the cast, and can be expected to simplify the assembly work and achieve an economical effect.

[0016]

As described above, according to the connecting portion of the plastic power cable of the present invention, it becomes possible to reduce the degree of necessity for the linearity of the cable as in the conventional case, and the time required for the straight-out work. Can be shortened. Also, by press-fitting the cast, it is possible to improve the adhesion at the interface between the cable core and the molded rubber insulator,
A stable, high-performance connection can be realized over a long period of time.

[Brief description of drawings]

FIG. 1 (a) is a longitudinal sectional view of an essential part of an embodiment of a first characteristic of a connecting portion of the present invention, and FIG. 1 (b) is a sectional view of a fitting structure of a cast and a molded rubber insulator. is there.

FIG. 2 is a vertical cross-sectional view of an essential part of an embodiment of a second feature of the connection portion of the present invention.

FIG. 3 is a longitudinal sectional view of an essential part of an embodiment of a third characteristic of the connection portion of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of an example of a conventional plastic power cable connection portion.

[Explanation of symbols]

 1 Cable Core 2 Conductor Connection Part 3 Cable Sheath 4 Molded Rubber Insulator 41 Large Diameter Part 42 Small Diameter Part 5 Gibbs 51, 52 Annular Protrusion 53 Extension Part 6 Annular Groove 7 Waterproofing 8 Annular Cushion

Claims (3)

[Claims] 1. A cylindrical shape extending over a large-diameter portion and a small-diameter end portion of a molded rubber insulator, the outer peripheral surface of the cable core being closely contacted with the inner peripheral surface outside the cable conductor connecting portion, A plastic electric power, characterized in that a cast of a highly rigid material is mounted, and the inner peripheral portion of the cast and the large diameter portion and / or the small diameter portion have a fitting portion. Cable connection. 2. An annular cushion material is mounted on a cable core outside the small end diameter portion of the molded rubber insulator in which the inner peripheral surface is provided in close contact with the outer peripheral surface of the cable core outside the cable conductor connecting portion. A cylindrical cast member having a high rigidity is mounted over the annular cushion member and the small diameter end portion of the molded rubber insulator, and the inner peripheral portion of the cast member and the molded rubber insulator are mounted. A connecting part of a plastic power cable, wherein the small end diameter part of the has a fitting part. 3. A molded rubber insulator having an inner peripheral surface closely contacted with an outer peripheral surface of a cable core on the outside of the cable conductor connecting portion to cover the molded rubber insulator in a cylindrical shape with two cracks in the longitudinal direction, A cast of high material is mounted, the joint in the lengthwise direction is mechanically connected, and the inner peripheral portion of the cast and the large diameter portion and / or the small diameter portion of the molded rubber insulator are fitted. A connecting portion for a plastic power cable, which has a joint portion and is further waterproofed by arranging an extension portion in the length direction on the cable sheath.