JPS6038807B2 - Coaxial cable manufacturing method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a bag cable.

Conventionally, in coaxial cables consisting of a center conductor and an outer conductor, the structure of the insulator part that is located between these two conductors and supports them has been an important issue.From the standpoint of reducing attenuation, It is said that a dielectric constant close to that of vacuum to air is preferable, and an insulator with a dielectric constant as small as possible is desirable. Therefore, various measures have been taken to hold both conductors, such as using foamed plastic as an insulator, using plastic supports intermittently in the length direction, or extruding plastic. The present invention was also made for the purpose of supporting both conductors with this insulator with a low dielectric constant, and one of its advantages is that the cavity of the insulator is extremely large, so it has a low attenuation amount. It can be a coaxial cable. A feature of the present invention is that a plurality of plastic tapes each having a V- or U-shaped cross section are twisted around the center conductor as a central axis, and the plastic tape is used as an insulating support and the tape is wrapped around the outside of the center conductor. The method involves providing layers and an outer conductor, and can be manufactured using a single assembly machine. Hereinafter, the present invention will be explained in detail with reference to the attached drawings.

FIG. 1 is a perspective view showing the structure of a coaxial cable that can be manufactured according to the present invention.

Around the center conductor 1, a plurality of tapes 2 (six tapes in the figure) each having a U-shaped cross section are fused around the center conductor 1. A tape-wrapped layer 5 and a cylindrical outer conductor 3 are provided on the outside thereof, and a tape-wound layer and a jacket 4 made of an extruded plastic coating layer are further provided on the outside. If the center conductor 1 is thin, a plurality of plastic tapes bent and formed into a V-shaped cross section may be twisted around the center conductor 1 to serve as an insulator between the two conductors. Further, the number of bent tapes may be any plurality, but depending on the tape quality, thickness, etc., it is possible to use a number that does not impair the strength of the cable. The material of the molded tape can be almost any plastic material such as polyethylene or polyester, and the thickness depends on the thickness of the cable, but a thick tape of 100 mm or more is suitable. The thicker the cable, the more appropriate it is to increase the thickness. In this way, the coaxial cable according to the present invention is characterized in that a plurality of bent plastic tapes are inserted between the two conductors as supporting insulation between the center and outer conductors, and in addition, a plurality of bent plastic tapes 2 are inserted between the two conductors. Wrap the book around the center conductor 1, and then wrap the tape 5 horizontally around the center conductor 1.
and 2 are bundled together and an outer conductor 3 is provided on the outside of the bundle, making it a strong cable. This is due to the fact that the connection between the center conductor 1 and the tape 2 is strong, and that a plurality of tapes 2 are integrated into one, making it difficult for the individual tapes 2 to deform or fold. FIG. 2 shows yet another structural example, showing an optical composite cable in which an optical fiber 0 is housed in a bent tape 2.
In the coaxial cable manufactured according to the present invention, a large cavity is created between both conductors, so it is always possible to accommodate an optical fiber or the like in this space. Further, one or more optical fibers may be accommodated in one tape 2. As explained above, since the coaxial cable manufactured according to the present invention has an insulating layer formed of a folded tape, the insulating layer has a large amount of space, so that a coaxial cable with low attenuation can be obtained.

Next, the manufacturing method of the present invention will be explained.

FIG. 3 is a diagram explaining the principle of the manufacturing method. In the figure, the winding of the bending tape 2 is shown for only one piece in order to reduce the complexity of the figure, but in reality, the same wrapping can be used for any desired textbook. First, a metal wire that will become the center conductor 1 is drawn out straight from a bobbin 11, and this becomes the central axis of the cable and its manufacture. Next, a plastic 2 bent into a U or V shape is wrapped around this.

This tape 2 is fed out from the tape pad 12, and immediately thereafter guided to a bending machine 16, where it is bent into a U or V shape in cross section, and immediately thereafter wound onto the center conductor 1. In reality, a plurality of tapes are wound, but in order to stably perform this winding, it is effective to use a gathering die 17 for the tape 2. Moreover, the gathering die 17 can be used to wrap a plurality of tapes 2, the former 16, and the tape 2. It is better to rotate together with the pad 12. In this way, a central conductor and an insulating layer outside it are provided. Immediately after a plurality of tapes 2 are twisted together, it is effective to wrap the tapes 5 horizontally immediately after twisting them to increase their strength. Next, the outer conductor 3 is guided into a cylindrical molding machine 18 with a pad-shaped metal tape 13 attached vertically.
By surrounding the insulator, a cylindrical outer conductor is formed. Thereafter, if necessary, the tape 4 serving as the outer covering may be horizontally wound, or an extrusion covering may be applied in a separate step. Further, after the tape 3 is formed into a cylinder, the joining portions of the tape may be welded. As mentioned above, the principle of the manufacturing method of the present invention is to bend and form a flat tape onto a straightly fed center conductor, attach a plurality of tapes with the die part, wrap the tape horizontally around the center conductor, and then apply the tape to the outside. The principle is to perform cylindrical molding and providing the conductor in a series, and it is also possible to perform the tape Fujimaki sheath on the outer conductor and the seam welding of the outer conductor in a series.

Since production is possible using such a simple method, the present invention is extremely easy to implement, requires simple equipment, and has extremely high productivity.

It goes without saying that a plurality of coaxial cables of the present invention provided with an appropriate jacket (tape wrapping layer and/or extruded coating layer) may be assembled.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a coaxial cable that can be manufactured according to the present invention, FIG. 2 is a sectional view of the cable showing another structure according to the present invention, and FIG. 3 is a perspective view illustrating the principle of the coaxial cable manufacturing method of the present invention. It is a diagram. In these figures, 1 is a center conductor, 2 is a folded tape, 3 is an outer conductor, 4 is an outer cover, 5 is a horizontally wound tape, 10 is an optical fiber, 11 is a bobbin, and 12, 13, 14, 15 are tape pad, 16 is a bending machine, 17 is a set of dies,
18 indicates a cylindrical former. Car diagram Wan 2 Zu Li 3 diagram

Claims (1)

[Claims] 1. On a central conductor running in the longitudinal direction, a plurality of plastic flat tapes are bent into U- or V-shaped cross sections and wrapped radially to form an insulating structure, and the tape is placed on the outside of the tape. A coaxial cable characterized in that the above-mentioned insulating structure is pressed and held by horizontal winding, and then a metal tape is vertically attached and formed around it to form a cylindrical outer conductor in a series of steps. Production method.