JPH0614327Y2 - Connection part of metal foil composite tape for power cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to improvement of a connecting portion of a metal foil composite tape for a power cable.

<Prior Art> In a water-impervious plastic power cable (cross-linked polyethylene power cable), an outer metal shielding layer has a water-impervious function.

As such a water-impervious plastic power cable, an insulating plastic film (for example, polyvinyl chloride film) is provided on one side of a metal foil (for example, lead foil), and a semiconductive plastic film (for example, carbon-mixed polyvinyl chloride film) is provided on the other side. A metal foil composite tape laminated with each film) is vertically coated on the outer semi-conductive layer of the cable core with the semi-conductive plastic film facing inward, and a plastic sheath (vinyl chloride sheath) is extrusion-coated directly on it. , The metal foil composite tape is heat-sealed by the heat at the time of extrusion (the overlapping part is overlapped with the edge of the insulating plastic film and the edge of the semi-conductive plastic film) and the metal foil composite tape Known to heat bond the insulating plastic film surface and the inner surface of the plastic sheath. A.

In the above-mentioned metal foil composite tape, in order to achieve the electrical shielding function for the cable, it must be in an electrically conducting state over the entire length of the cable or between the cable spans, and even at the connecting portion of the metal foil composite tape, the electrical conductivity thereof must be maintained. In order to ensure the electrical continuity, conventionally, as shown in FIG. 3, both composite tapes 1a 'and 1b' (12 'is an insulating plastic film, 11' is a metal foil, 13 ').
Is a semi-conductive plastic film)
The metal foil is exposed at these overlapping portions, and these exposed metal foil portions 15a 'and 15b' are joined by solder 2 '.

<Problems to be solved> However, the joint has a high rigidity due to the solder, and the metal foil composite tape (low rigidity) is directly connected to this high rigidity portion, and the rigidity change at the boundary between the two is sharp. Because of this, the stress concentration at the boundary is significant, and the joint is easily damaged.

An object of the present invention is to provide a connecting portion of a metal foil composite tape capable of sufficiently reducing stress concentration.

<Means for Solving the Problems> The connection portion of the metal foil composite tape for power cables according to the present invention is formed by bonding an insulating film on one side of a metal foil and a semiconductive film on the other side, and joining them together. The semi-conductive film surface of one end of one composite tape in the composite tape to be faced faces the insulating film surface of the other end of the other composite tape, and the semi-conductive film surface of the one end is a predetermined length from the end. The metal foil is exposed by removing the metal foil at a separated portion, and the metal foil is exposed by removing the insulating film surface at the other end by a predetermined distance from the end, and these exposed metal foil portions are exposed. Is joined by solder, and the contact surfaces of the insulating film and the semiconductive film before and after the joining portion are heat-sealed.

<Description of Embodiments> The present invention will be described below with reference to the drawings.

FIG. 1 is a top view showing an embodiment of the present invention, and FIG.
It is a II-II sectional view in the drawing.

In the figure, 1a and 1b are metal foil composite tapes for power cables to be joined together, and an insulating plastic film 12 is provided on one side of a metal foil 11 (eg, aluminum foil, lead foil).
(For example, polyvinyl chloride film, polyethylene film), and a semi-conductive film 13 (for example, carbon mixed polyvinyl chloride film) is laminated on the other surface. The end of each composite tape is cut diagonally, and the angle is 30 to 60 °, preferably 45 °.
The semiconductive film surface at one end of the one composite tape 1a and the insulating film surface at the other end of the other composite tape 1b face each other.

Reference numeral 15a is a portion where the semiconductive film surface at one end is removed to expose the metal foil, and the exposed portion 15a (width is usually about 10 to 100 mm) is diagonally oriented corresponding to the diagonal cut. 15b is a portion where the insulating film surface at the other end is removed to expose the metal foil.
b completely overlaps the exposed portion 15a vertically to form a space, and these metal foil exposed portions 15a and 15b are the solder 2 loaded in this space (the solder volume is equal to the space volume).
Are joined by. The semi-conductive film surfaces 131a and (132a) and the insulating film surfaces 121b and (122b) that are in contact with each other before and after the joining portion are heat-sealed to each other.

In this case, the metal foil exposed portion 15a,
The solder 2 is interposed between 15b, the joint is sandwiched by release paper,
Depending on the press, for example, 150 ℃ x 5 minutes x 5kg / cm ²
Conditions (This condition is for insulating plastic film,
The pressure may be set according to the material of the semiconductive plastic film).

<Effects of the Invention> The connecting portion of the metal foil composite tape for power cable according to the present invention is configured as described above, and there are two parts of the composite tape on both sides of the solder joint portion. Yes, the rigidity change between the low rigidity) and the solder joint (high rigidity) becomes slow due to the interposition of these two parts (medium rigidity), so stress concentration can be relaxed well and damage to the joint can be prevented. It can be prevented satisfactorily. Further, since both sides of the solder joint are heat-sealed, and the solder joint area can be reduced by the amount of external force of the welded portion, the solder joints can be downsized.

[Brief description of drawings]

FIG. 1 is a top view showing a connecting portion of a metal foil composite tape for a power cable according to the present invention, and FIG. 2 is a II-II in FIG.
A sectional view and FIG. 3 are explanatory views showing a conventional example. In the figure, 1a and 1b are composite tapes, 11 is a metal foil,
12 is an insulating film, 13 is a semi-conductive film, 12
Reference numerals 1b and 122b denote insulating film surfaces, and 131a and 132b.
a is a semiconductive film surface, 15a and 15b are exposed metal foil portions, and 2 is solder.

Claims (1)

[Scope of utility model registration request] 1. A composite foil in which an insulating film is laminated on one surface of a metal foil and a semiconductive film is laminated on the other surface to be bonded to each other. Facing the insulating film surface of the other end of the composite tape, and removing the semiconductive film surface of the one end at a portion separated by a predetermined length from the end to expose the metal foil, and insulating the other end. To remove the metal foil by removing the flexible film surface at a portion separated from the end by a predetermined length, and joining the exposed metal foil portions with solder,
A connecting portion of a metal foil composite tape for a power cable, characterized in that the contact surfaces of the insulating film and the semiconductive film before and after the joining portion are heat-sealed.