JPH0226189Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Background and Purpose of the Invention] The present invention relates to the structure of a connecting portion of a power cable, particularly a rubber- or plastic-coated power cable.

This type of cable connection part using a heat-shrinkable tube as a covering member is widely used as a connection part for power distribution cables and the like because it is easy to assemble the connection by simply heating it. On the other hand, in these structures, a general method for obtaining higher insulation performance is to thicken the insulation layer at the connection portion. And this method is
There are two methods: one is to stack a large number of insulating tubes, and the other is to cover thick tubes. However, in the former method, there is a problem in that there is a space required to insert the tube into the cable in advance and store it, and there are also problems in that the time required for heating and shrinking is increased. On the other hand, the latter method has a problem in that the temperature difference between the heated outer and inner surfaces becomes large due to the thick walled tube, making uniform contraction difficult.

At the extreme, even if the outer surface contracts, the temperature of the inner surface does not rise, which causes wrinkles on the inner surface, leading to a decline in insulation performance.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power cable connection part that eliminates the drawbacks of the prior art described above and improves assembly workability and insulation performance.

The gist of the present invention is that an elastic cylindrical body is used as part or all of the insulating layer of the connection portion.

As the elastic cylindrical body, for example, ethylene propylene rubber, silicone rubber, etc. are used. Note that the elastic cylindrical body may be composed of a single insulator, or it may be composed of a composite body with a semiconductive layer integrally provided on its outer surface.

Further, by tapering the outer shape of both ends of the cylindrical body, it is possible to easily attach a shield formed on the outer periphery of the cylindrical body.

[Embodiment] Next, an embodiment of the power cable connection part of the present invention will be described with reference to the attached drawings. In FIG. , the shielding layer 2, the outer semiconducting layer 3, and the insulator 4 are successively removed. Reference numeral 6 denotes a conductor connecting tube that electrically and mechanically connects the end portions 5 of the cable conductors exposed in this manner. Reference numeral 7 denotes a conductive shield layer provided over the outer periphery of the end portions of the conductor connecting tube 6 and both insulators 4, and a heat-shrinkable conductive tube, for example, is employed for this. It is desirable that both ends of the shield layer 7 be tapered in order to effectively cope with high voltage. Reference numeral 8 denotes an electric field relaxation layer provided over the outer periphery of the end portions of the shield layer 7, both cable insulators 4, both cable external semiconducting layers 3, and both cable shielding layers 2. A dielectric constant tube is adopted. Reference numeral 9 denotes a first insulating layer provided around the outer periphery of the electric field relaxation layer 8, and a heat-shrinkable insulating tube is employed for this. Reference numeral 10 denotes a second insulating layer provided around the outer periphery of the first insulating layer 9, and this is an elastic cylindrical body having a necessary wall thickness. The inner diameter of the elastic cylindrical body 10 is formed to be somewhat smaller than the outer diameter of the first insulating layer 9.
The elastic tightening force brings the interface between the two into close contact. Therefore, the inner diameter of the elastic cylindrical body 10 is set to the outer diameter of the first insulating layer 9 so that when the elastic cylindrical body 10 is inserted through the outer periphery of the first insulating layer 9, a desired pressure bonding force is generated between the two. must be adjusted accordingly. The inner diameter of the elastic cylindrical body 10 can be adjusted using a mold during molding, and the outer diameter of the first insulating layer 9 can be adjusted by knowing changes in the thickness and shrinkage rate of the insulating tube. In addition, if the inner diameter of the cylindrical body 10 becomes smaller and the insertability of the cylindrical body 10 deteriorates, the end of either the insulating layer 9 or the electric field relaxation layer 8 may be tapered. , and an insulating layer 9
By applying an insulating lubricant (silicone oil, silicone grease, etc.) to one or both of the surface of the cylindrical body 10 or the inner surface of the cylindrical body 10, insertion becomes easy. Reference numeral 11 denotes an external semiconductive layer provided over the outer periphery of the second insulating layer 10, both ends of the first insulating layer 9, and both ends of the electric field relaxation layer 8, which includes a heat-shrinkable semiconductive tube. Adopted. Note that the heat-shrinkable tube may be composed of a single semiconductive tube, or it may be composed of a composite tube with a semiconductive layer on the outside and an insulating layer on the inside. 12
is a shielding layer provided around the outer periphery of the external semiconducting layer 11 so that both ends thereof are in contact with the cable shielding layer 2, and this is made of, for example, a copper tape wrapping layer, a copper wire braided layer, or a large number of copper wires longitudinally attached. layers etc. are adopted. 1
Reference numeral 3 denotes a tin-plated annealed copper wire that is wound around the shielding layer 12 in order to fix both ends of the shielding layer 12 onto the cable shielding layer 2.

FIG. 2 shows another embodiment in which tapered portions 14 are formed at both ends of the second insulating layer 10.
The same numbers as those in FIG. 1 refer to the same or similar parts, respectively.

According to this embodiment, the main insulating layer necessary for increasing the voltage of the connection part is formed by inserting an elastic cylindrical body, and is therefore formed by laminating a large number of heat-shrinkable tubes. In comparison, assembly work can be completed in an extremely short time. In addition, heating work can be omitted. Furthermore, if a device is used as the elastic cylindrical body, such as having a semiconductive layer integrally provided on the outer periphery in advance, the work of attaching the external semiconductive layer 11 can be omitted. Furthermore, the heating work basically consists of the shield layer 7, the electric field relaxation layer 8, and the first insulating layer 9.
This significantly reduces material aging, foaming, and burnout phenomena caused by heating.

[Effects of the invention] According to the invention, since the insulating layer necessary for increasing the voltage of the connection part is composed of a pre-formed elastic cylindrical body, the insulating layer can be used to form a large number of heat-shrinkable tubes. Compared to conventional connections of this type that are made up of laminated layers, not only is there no need for long-term heating operations, but the number of tubes used is significantly reduced, so there is no restriction on tube storage space. It can provide excellent advantages such as:

As described above, the present invention can extremely effectively achieve the purpose described at the beginning, and can be said to have extremely great practical value.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the power cable connection part of the present invention, and FIG. 2 is a cross-sectional view showing another embodiment. 1: Power cable, 2: Shielding layer, 3: External semiconducting layer, 4: Insulator, 5: Conductor, 6: Conductor connection pipe,
7: Shield layer, 8: Electric field relaxation layer, 9: First insulating layer (heat-shrinkable insulating tube), 10: Second insulating layer (elastic cylindrical body), 11: External semiconducting layer, 1
2: Shielding layer, 13: Tin-plated annealed copper wire.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a cable conductor whose ends are exposed by successively stripping off the shielding layer, external semiconducting layer, and insulator at the ends thereof, and connecting the exposed ends with a conductor connecting tube. A shield layer and an electric field relaxation layer made of heat-shrinkable tubes are sequentially formed on the periphery of the conductor connection portions of both power cables, and an elastic cylindrical layer is formed on the periphery either directly or through a thin insulating layer made of heat-shrinkable tubes. A power cable connection section characterized in that it is constructed by forming a main insulating layer consisting of a body. (2) The power cable connection part according to claim 1, which is a utility model registration, using a composite elastic cylindrical body composed of a semiconductive layer on the outside and an insulating layer on the inside as the elastic cylindrical body. (3) The power cable connection part according to claim 1, which is a utility model registration, and uses an elastic cylindrical body having a tapered part formed at one or both ends thereof. (4) The power cable connection part according to claim 1, which is a utility model registration and uses a heat-shrinkable tube for the electric field relaxation layer that has a tapered part formed at one or both ends thereof.