JPH0535604Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a leaky coaxial cable having a helical outer conductor.

[Prior Art] A conventional leaky coaxial cable will be explained with reference to FIG. The leaky coaxial cable 1 is formed by covering a central conductor 2 with an insulator 3 in a coaxial cylindrical shape, and wrapping a tape-shaped outer conductor 4 in a spiral shape with a certain gap provided on top of the insulator 3. The electromagnetic field is now leaking.

This spirally wound outer conductor 4 is designed to prevent adjacent outer conductors from coming into contact with each other, for example.
The insulating string 5 is knitted in the opposite direction to the outer conductor 4 to form a braided structure or the like to securely fix its position.

[Problems to be solved by the invention] By the way, in order to form the outer conductor into such a braided structure, a specific manufacturing device is required, and this manufacturing device includes a clockwise rotation mechanism for the outer conductor and the insulating string, It is necessary to provide a leftward rotation mechanism and a mechanism for alternately intersecting these, which complicates the configuration of the device and limits how high the speed can be increased. In addition, when attaching a connector to the end of a cable, it is necessary to unravel the braided structure of the external conductor and insulating string, and then cut and remove the unnecessary insulating string.
The workability is extremely poor.

This invention was made in view of the above points, and aims to provide a leaky coaxial cable that is easy to manufacture, can be made at high speed, and is easy to attach to the cable.

[Means and operations for solving the problem] In this invention, a polyolefin insulating string is wound in the gap between the spirally wound outer conductor in the same direction as the outer conductor and at the same pitch. The position of the outer conductor is firmly fixed by ensuring a gap between the outer conductors and by heating and fusing this insulating string with the polyolefin tape layer placed on the outer conductor. It was formed in

Therefore, adjacent comrades of the outer conductor do not come into contact with each other, and the insulating string can be provided by spirally winding in the same direction as the outer conductor, which simplifies the manufacturing equipment. It is possible to increase the speed.

[Example] Hereinafter, an example of this invention will be described based on the drawings. FIG. 1 is a perspective view showing one end portion of a leaky coaxial cable showing a first embodiment of this invention, and FIG. 2 is a cross-sectional view thereof. That is, the leaky coaxial cable 10 has a conductor bundle 13 made of a plurality of thin metal core wires serving as an external conductor on the outer periphery of the central conductor 11, which is coated with insulation by extruding an insulator 12 into a coaxial cylindrical shape. Wrap multiple strands in a spiral. Between these conductor bundles 13 is this conductor bundle 1.
At the same time as the conductor bundles 3 are wound, an insulating string 14 made of polyolefin string is wound in the same direction so as to prevent adjacent conductor bundles 13 from coming into contact with each other. Then, a polyolefin-based tape layer 15 is placed on top of this by an appropriate method such as winding, and then the insulating string 14 portion is heated from around this tape layer 15 using a heater or the like, and the polyolefin-based tape layer 15 between the conductor bundles 13 is heated. The insulating string 14 and the polyolefin tape layer 15 are heat-sealed and integrated.

Therefore, since the conductor bundle 13, which is a spirally wound outer conductor, is firmly fixed by heat-sealing the insulating string 14 and the tape layer 15 thereon, there is no possibility that adjacent comrades will come into contact with each other. It can be firmly fixed without any problem. In addition, since the conductor bundle 13 and the insulating string 14 are wound in the same direction, there is no need to intersect the rotation mechanisms in the left and right directions, and it is possible to use not only a feed-out rotation type manufacturing device but also a take-up rotation type manufacturing device, which reduces the manufacturing speed. Enables high speed.

Next, a second embodiment will be described based on FIG. The leaky coaxial cable 30 in this case has polyolefin tape layers 31 and 32 disposed both above and below the conductor bundle 13 and the insulating string 14.
Then, the tape layers 31, 32 and the insulating string 14 are thermally fused and integrated by heating from around the insulating string 14 in the same manner. Therefore, in this case, it is possible to fix the outer conductor more reliably and firmly than in the first embodiment.

Polyolefin-based insulating strings and the like have good insulation properties, are easily heat-sealed, and have good electrical properties, so they can be used as leaky coaxial cables with low transmission loss.

Of course, the sheath applied to the insulator 12 or the outer conductor may be used as is to heat-seal the polyolefin insulating string, and in this case, the polyolefin tape should not be used. Can be omitted.

Moreover, although a conductor bundle consisting of a plurality of metal core wires has been described as an external conductor, a metal tape can also be used instead.

[Effect of the invention] As explained above, the leaky coaxial cable of this invention has a spiral winding direction in which the conductor bundle, which is the outer conductor, and the polyolefin insulating string placed in the gap are wound on the insulator. Since the same direction and pitch are used, the mechanism of the manufacturing equipment is simple, and not only a feed-out rotary type manufacturing equipment but also a take-up rotary type manufacturing equipment can be used, which greatly speeds up the manufacturing speed. becomes possible.

Additionally, when attaching a connector to the end of a leaky coaxial cable, you can simply cut the polyolefin tape circumferentially with a knife and remove the polyolefin insulating string integrated with it at the same time. It gets easier.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a part of a leaky coaxial cable according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the leaky coaxial cable shown in FIG. 1, and FIG.
FIG. 4 is a cross-sectional view of a leaky coaxial cable showing a second embodiment of the present invention, and FIG. 4 is a perspective view of a conventional leaky coaxial cable. 11... Center conductor, 12... Insulator, 13...
Outer conductor, 14...Insulating string, 15, 21, 31,
32...Tape layer.

Claims (1)

[Scope of utility model registration request] An insulator is coated around the center conductor, an outer conductor is wound spirally on top of the insulator, and a certain gap is provided between the outer conductors, allowing the electromagnetic field to leak through this gap to enable wireless communication. In the leaky coaxial cable, one or more polyolefin-based insulating strings are wound on the insulator in the gap between the outer conductors in the same direction and at the same pitch as the direction in which the outer conductor is wound, and A leaky coaxial cable characterized in that it is formed by disposing a polyolefin tape layer on the outer conductor and heat-sealing the tape layer and the insulating string.