JPS62131417A - Of cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) KI 51 nJI relates to improvements in OF cables having an insulating layer comprising at least a portion of a polyolefin plastic film.

(Prior Art) Fig. 9 is an explanatory diagram of a conventional OF cable.

In the drawings, (+1 is a cable conductor made of copper stranded wire or aluminum stranded wire with an insulating oil passage (la) formed inside, and ■ is made of one of polyethylene film, polypropylene film, polybutene film, or a combination of these) You can either wrap a plastic film, wrap a composite stitched U paper that is made by laminating kraft paper on both or one side of a polyolefin plastic film, or alternately wrap a polyolefin plastic film and kraft paper. This is an insulating layer made of polyolefin plastic.

On the outside of the cable core (C), which is equipped with an insulating layer (C) containing at least a portion of the film, is a corrugated gold V4 north (31) made of aluminum, stainless steel, etc. with continuous spiral corrugations. Further, on its outer periphery, an anticorrosion layer (not shown) is applied by extruding a plastic material exclusively made of polyethylene or polyvinyl chloride.

(Problems to be Solved) 1-In the OF cable having the conventional spirally corrugated metal sheath (31) described above, the corrugated troughs are always at one location in the same cross section -L. Core (+1, !: Touching. Therefore, when connecting the connecting steel pipe and metal source (31) at the end of the cable with lead work or welding, the plastic film of the insulating layer ■ may be damaged by melting due to the connection. There were many.

Therefore, as a countermeasure to solve such problems, -1
In this regard, the following two measures have been taken.

One is to use a lead-resistant material such as kraft paper, a composite insulating paper made by laminating kraft paper on both sides of a fluoroethylene propylene copolymer film, or polymethyl pentane near the outer periphery of the insulating layer. Composite insulating paper, which is made by laminating kraft paper on both sides of the film, is used to avoid the effects of spot stickiness caused by four-way lead.
Alternatively, methods have been taken such as using such lead-resistant materials for insulating layers in areas where connections are likely to occur.

Part 2: For example, the lead work of the connection part is fused E1. j, 1oo′
Methods that have been used include using low iQ solder inside and outside the metal source, and using a so-called oil-dried lead method in which insulating oil is poured from an oil tank between the metal source and the cable core, and the lead is soldered several times while being cooled.

Yet another technical trend is to use so-called lead-free connections, which use backing, 01J, etc., to avoid the use of fire during the process.

However, all of the above methods have the following problems.

The method of using lead-resistant materials is originally based on insulation technology (
The use of polyolefin plastic film, which is desirable for electrical strength, εx tan δ) or economical use, is limited, and it is necessary to provide many kraft paper sheets with poor εX tan δ, or expensive fluoroethylene propylene copolymer or polymethyl There is a problem in that a composite insulating paper using bentene has no choice but to be used. Or, when different types of polyolefin plastics are mixed in the insulation layer of the same cable, there are differences in paper wrapping conditions, differences in thermal expansion, and differences in the slipperiness of the tape.
There have also been reports of poor management and workability due to an increase in materials.

In addition, methods using low-temperature solder or oil pouring lead work are extremely difficult and have poor workability.Furthermore, with lead-free connections, the corrugation of the metal source is a continuous spiral, so it is difficult to tighten the O-rings. However, since it always goes around the valleys and peaks, it is difficult to achieve perfect q-density, and the work is difficult, resulting in a complicated connection structure.

(Means for Solving the Problems) The present invention provides an improved OF cable that solves the above-mentioned problems.The present invention is characterized by an insulating layer in which at least one part of the OF cable is made of polyolefin plastic film. The cable core is provided with a ring-shaped corrugated metal sheath on the outside of the cable core.

(Example) Fig. 1 is a longitudinal cross-sectional view of an embodiment of the OF cable of the present invention, Fig. 2 is a cross-sectional view thereof, and the same figure (A) is a cross-sectional view of the OF cable of the present invention.
A cross-sectional view at X+, the same figure (b) is a cross-sectional view taken along line X2-X2 in FIG.

In the present invention, the cable core (C) is provided with an insulating layer (C) formed on the cable conductor (11) having an insulating oil passage (Ial) at least in part with a polyolefin plastic film. This is similar to the conventional OF cable shown in FIG.

However, the corrugated metal sheath (3) provided on the outside of the cable core (C) is not a continuous spiral corrugation, but has one trough (3b) or peak (3a) in the direction perpendicular to the core axis. It is an independent ring-shaped corrugated metal sheath (3).

Figure 3 is a front view (A) and a side view of an example of the rotating ring forming the ring-shaped corrugated metal sheath (3), and as shown in the drawing, it rotates once and corresponds to the corrugated pitch. A plurality of rotary rings (■) with one end open at a distance P apart from each other are arranged in the axial direction while changing the inner diameter from small to small. By synchronizing the advances by P, a ring-shaped corrugation can be applied to the metal sheath. This method is the most Hq
This is a common method. Another ring-shaped corrugation method is to apply strong electromagnetic force to the part of the metal sheath that forms the valley.
There is a machining method that utilizes the so-called r'116fi force, which utilizes the repulsive force between the metal sheath and the repulsive magnetic field created by the eddy current flowing through the metal sheath. In the case where the metal sheath is an aluminum sheath, which is often used in OF cables, it is particularly suitable because the repulsion magnetic field can be strengthened because the metal sheath has high conductivity through which eddy currents flow. This method is particularly preferable for the ring-shaped wave-applied beads of the present application because it is extremely easy to apply force locally in a ring shape without contact.
It is not particularly limited.

5 to 8 are longitudinal sectional views of a series of connections of an OF cable having a ring-shaped corrugated metal sheath (3) of the present invention.

Figure 5 shows the rfIl of one or more peaks (3a) of the ring-shaped corrugated metal sheath (3), and the end 1 of the connecting steel blue I'ID of the junction box over its entire circumference. % reduction IY part (lla> and spot welding ('tri, arc, TI
G, plasma, laser, etc.) or spot lead ID to maintain airtightness, and then an epoxy/resin reinforcing layer q1 is applied to the -L to give it the same mechanical strength as I. .

Figure 6 shows a tube expansion jig inserted into the ring-shaped corrugated metal sheath at the end of point 3) to expand the tube by one or two peaks and flatten it (3
c), perform spot welding or spot lead work 112+ in the same way as above to maintain airtightness between this flat part (3c) and the reduced diameter end part (lla) of the connecting steel pipe 01), and then 50m of ebony/resin reinforcement was provided on the top.

FIG. 7 shows an example of a lead-free joint, in which an O-ring 0Φ is inserted into the valley part (3b) of the ring-shaped corrugated metal sheath (3), and the reduced diameter part of the end of the connecting steel pipe 110 is inserted into this part. (I Ia) can be covered to maintain airtightness, and a reinforcing layer q1 made of Epoquine resin is provided on the "-" to mechanically protect it.

Furthermore, Fig. 8 shows another example of a lead-free joint, where the peak part (3a) of the ring-shaped corrugated metal sheath (3) is slightly flattened, an OIJ ring qΦ is inserted into this part, and the same as above is applied to this part. The reduced diameter end portion (Ila) of the connecting steel pipe CD can be reversed to maintain airtightness, and a reinforcing layer a1 made of epoxy/resin is provided thereon.

In the lead-free joint shown in FIGS. 7 and 8, the number of O-rings 041 is not limited to one, and the number can be increased as necessary.

Generally, when an OF cable is connected, air remains at the cut end of the cable, so after the connection box is overturned, a vacuum is drawn from the end of the cable to remove air, and then insulating oil is injected into the cable. In this case, in the conventional continuous spirally corrugated metal sheath, since the gap between the cable core and the metal sheath is continuous, the above-mentioned evacuation can be carried out easily and reliably. However, in the ring-shaped corrugated metal sheath of the present invention, if the air that has passed through one corrugation to the cable side remains deep inside, it will take a long time to evacuate the junction box (-minutes). It may take time.

Figure 4 is a cross-sectional view of an example of a cable that takes measures against such a case, and shows the valley i?
(3b) is provided with two concave portions 1 which are continuous in the length direction on the inner surface thereof, thereby making it possible to carry out evacuation and degassing easily and reliably as in the conventional case.

(Effects of the Invention) According to the OF cable of the present invention described above, since the ring-shaped corrugated metal Ii1 north is applied on the cable core,
Since a gap can be created between the cable core and the gold G4 sheath, the connection I! Welding or lead work can be employed to form T≦. As a result, it has become possible to use low-melting-point polyolefin plastic films such as polyethylene, polypropylene, and polybutene for the cable insulation layer, and it is also possible to use them in a uniform manner with the highest performance and economy, which improves performance and economy. A highly attractive OF cable can be realized.

In addition, since it is possible to make a lead connection using an O-ring or the like, there is an effect that the connection can be made without using fire on the road 5.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of the OF cable of the present invention, FIG. 2 is a cross-sectional view thereof, and (A) is a cross-sectional view of
3 is a front view (a) and a side view of the corrugated rotating ring. FIG. 4 is a cross-sectional view of another embodiment of the OF cable of the present invention. 5 to 8 are all longitudinal sectional views of the connecting portion of the OF cable of the present invention. FIG. 9 is a vertical cross-sectional view (a) and a cross-sectional view (middle) of a conventional OF cable. C... Cable core, 1... Cable conductor, 2...
・Insulating layer, 3...Ring wand corrugated metal source, 3a...
・Source mountain part, 3b... Sheath valley part, 3c... Sheath uneven part, 5... Rotation/g, 11... Steel pipe for connection, I2... Welded or leaded part, 13 ... Reinforcement layer, 14
...0 ring, 15...recess. Arithmetic 5 Calculation 6 Recording rod 7 Figure Hand 8 Figure

Claims (4)

[Claims] (1) An OF cable characterized in that a ring-shaped corrugated metal sheath is provided on the outside of a cable core provided with an insulating layer having at least a portion of a polyolefin plastic film. (2) The OF cable according to claim 1, wherein the polyolefin plastic film is one or a combination of polyethylene film, polypropylene film, and polybutene film. (3) The OF cable according to claim 1, wherein the insulating layer is made of a combination of a polyolefin plastic film and kraft paper. (4) The OF cable according to claim 1, characterized in that the inner surface of the trough of the ring-shaped corrugated metal sheath is provided with a concave portion continuous in the length direction.