JPH09306250A - Fan-shaped power cable - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To make it possible to lay a cable having a larger capacity in a pipe of a limited size. A wall thickness T ₁ of a radius portion 31 of a protective sheath 3 of a power cable having a fan-shaped cross section is formed thinner than a wall thickness T _{2 of} an arc portion 32.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable having a fan-shaped cross section, which is twisted together so that the cross section is circular as a whole and is drawn and laid in a pipe. is there.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional electric power cable having a fan-shaped cross section is formed by twisting a plurality of such wires so that the cross section as a whole is circular. An insulator 2 having a predetermined thickness is provided on the outer circumference, and a uniform thickness T ₂ is provided on the outer circumference of the insulator 2 with a thickness sufficient to protect the insulator 2 from mechanical damage. Is provided with a protective sheath 3. Further, this fan-shaped power cable having a cross section can be twisted compactly so that the outer shape of the cross section as a whole becomes circular, so that there is no unnecessary space in the conduit 4 and the power cable is It can be installed with a high space factor to fill the inner diameter of the passage.

[0003]

However, when it becomes necessary to exchange a cable with a larger capacity for reasons such as an increase in power demand, a cable with a larger capacity generally has a size (diameter). Since the size is increased, the size (inner diameter) of the conduit 4 is often too small, which causes a problem that a new cable having an increased capacity cannot be drawn and laid in the conduit 4.

An object of the present invention is to provide a fan-shaped power cable that advantageously solves the above problems.

[0005]

In order to achieve the above-mentioned object, in the present invention, in a power cable having a fan-shaped cross section, the conductor comprises a conductor, an insulator outside the conductor, and a protective sheath outside the conductor. The wall thickness of the radius part in the above was made thinner than the wall thickness of the arc part.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a fan-shaped power cable according to the present invention will be described below with reference to illustrated examples. FIG.
1 shows an embodiment of the present invention, in which a conductor 1 made of a copper stranded wire or the like compression-molded so that its cross section has a fan shape has a predetermined electrical insulation thickness on the outer circumference. An insulator 2 such as cross-linked polyethylene is provided, and a protective sheath 3 such as polyvinyl chloride is provided on the outer periphery of the insulator 2. The protective sheath 3 has a radial portion 3
When the wall thickness of ₁ is T ₁ and the wall thickness of the arc portion 32 is T ₂ ,
Both wall thicknesses are formed so that T ₁ <T ₂ .

When a plurality of electric power cables having a fan-shaped cross section are twisted into a diameter D so that the outer peripheral shape of the whole cross section is circular, the arc portion 32 is exposed as the outer peripheral surface and the radius portion 31 is formed. Is a side part where adjacent cables are in close contact with each other and is not exposed to the outside. Therefore, the wall thickness T ₂ of the circular arc portion 32 is formed to have a thickness equivalent to the conventional one sufficient to protect the insulator 2 from mechanical damage, but the wall thickness T ₁ of the radius portion 31 is Since it is not necessary to take such consideration into consideration, that is, the wear is caused by the friction between the sheaths, the thickness is made as thin as possible.

In this way, by making the wall thickness T ₁ of the radius portion 31 as thin as possible with respect to the wall thickness T ₂ of the arc portion 32, the cross-sectional area of the conductor 1 can be made larger than that of the conventional one. Therefore, it is possible to lay a cable having a larger capacity and having a conductor 1 having a larger size than the conventional one in the conduit 4.

[0009]

As is apparent from the above, according to the present invention, the protective sheath 3 is provided in the electric power cable having a fan-shaped cross section.
The wall thickness T ₁ of the radius portion 31 in the circle is the wall thickness T _{2 of the} arc portion 32.
Since the conductor 1 is formed thinner than the conventional one, the conductor 1 can be made larger than the conventional one even though the diameter D of the entire twisted cable having a circular outer peripheral shape is the same as the conventional one. Therefore, it is possible to obtain the effect that it is possible to lay a cable having an increased size (capacity) in the existing pipeline 4.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a fan-shaped power cable according to the present invention.

FIG. 2 is a cross-sectional view showing a conventional fan-shaped power cable.

[Explanation of symbols]

 1 Conductor 2 Insulator 3 Protective sheath 31 Radius 32 Arc part 4 Pipeline

Claims (1)

[Claims] 1. A power cable having a fan-shaped cross section, comprising a conductor (1), an insulator (2) on the outside of the conductor (2), and a protective sheath (3) on the outside thereof, the radius portion of the protective sheath (3). A fan-shaped power cable, wherein the wall thickness (T ₁ ) of (31) is formed thinner than the wall thickness (T ₂ ) of the circular arc portion (32).