JPS6226125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in communication cables such as coaxial cables and balanced pair cables.

When a communication cable is laid in a conduit under a one-way road, a creep phenomenon occurs in which the cable moves in the direction of travel of the vehicle or other vehicle on the ground due to the action of inertia as the vehicle or other vehicle travels in one direction. arise. In this case, if the cable sheath is fixed, the internal cable core may move, causing the core wire or coaxial core to protrude or buckle at the connection part, causing trouble.

The creep phenomenon of the cable core can be prevented by making the frictional force between the sheath and the cable core sufficiently large.

As shown in Fig. 1, the communication cable manufacturing method that implements this involves integrating the cable core 1 with a core wrap 2 on its outer periphery, and integrating the core wrap 2 with a sheath 3 on its outer periphery. It becomes necessary. Cable core 1 and core wrap 2
Although integration with the core wrap 2 and sheath 3 can be sufficiently achieved by wrapping with tape, etc., it is difficult to sufficiently integrate the core wrap 2 and the sheath 3. The reason for this is that when extruding the sheath, a certain amount of clearance is provided between the core wrap 2 and the sheath 3 to make it easier to make the cross section of the sheath 3 circular and to prevent the core 1 from being affected by heat. This is because there is.

In order to strengthen the integrity between the core wrap 2 and the sheath 3, it is conceivable to use a material with a large coefficient of friction, such as a rubber tape, as the core wrap 2.
However, in this case, in the drying process after the core wrap is coated, the presence of the rubber tape or the like makes it difficult for internal moisture to escape, resulting in a very long drying time.

SUMMARY OF THE INVENTION An object of the present invention is to provide a communication cable in which the integrity between the cable core and the cable sheath is sufficiently and reliably maintained, and the cable core can be dried during the manufacturing process without any problem.

The communication cable of the present invention will be described with reference to FIGS. 2 and 3, which correspond to embodiments thereof. The cable core 1 is provided with a first core wrap layer 2A having air permeability and heat shielding properties around the outer periphery of the cable core 1. and said first
A second core-wrap layer 2B is provided on the outer periphery of the core-wrap layer 2A, which has adhesion to the adhesive layer of the double-sided adhesive laminate tape described below and has air permeability.A metal tape 4 is provided on the outer periphery of the second core-wrap layer 2B. A layer of double-sided adhesive laminate tape 7 having adhesive layers 5 and 6 is provided on both sides of the laminate tape 7, a cable sheath 3 made of plastic is provided around the outer periphery of the layer of laminate tape 7, and an inner adhesive surface 5 of the laminate tape 7 is provided with a cable sheath 3 made of plastic. is the second core wrap layer 2
B, and the adhesive layer 6 on the outer periphery is adhered to the cable sheath 3.

Note that in the present invention, adhesion includes fusion.

Next, a specific example of the present invention will be explained with reference to FIG. The cable core 1 has an inner layer made of a 24-cut assembly 1A made up of 24 0.9mmφ paper insulation cuts.
Eight coaxial cores 1B were twisted around the outer periphery, and eight 0.9 mmφ paper insulating cuts 1C were twisted around the outer periphery. For the coaxial core 1B, the center conductor was made of annealed copper wire of 2.6 mmφ, and the outer conductor was finished with an outer diameter of 10 mmφ, and a soft iron tape or paper tape was wrapped around the outer periphery to give an outer diameter of 11 mmφ. The first core wrap layer 2A was made by winding four sheets of paper tape horizontally to have an outer diameter of 41 mm. The second core wrap layer 2B was formed by roughly winding one sheet of polyethylene tape. Such a second core wrap layer 2B has air permeability. The double-sided adhesive laminate tape 7 used was an aluminum tape with polyethylene layers provided as adhesive layers on both sides. The cable sheath 3 was provided by extruding polyethylene to a thickness of 2 mm. In this state, the cable outer diameter was 46mm.

Such a communication cable is subjected to a drying process with the second core wrap layer 2B provided thereon to remove internal moisture and improve insulation resistance and dielectric strength. After that, the laminated tape 7 is covered vertically, and the cable sheath 3 is extruded and coated on the outside, and the heat generated at this time causes the adhesive layer 5 on the inside of the laminated tape 7 to
is adhered to the second core wrap layer 2B by fusion,
The outer adhesive layer 6 is adhered to the cable sheath 3 by fusion bonding and is integrated.

The second core wrap layer 2B is formed by loosely winding polyethylene tape, and this is to facilitate the release of moisture during the drying process, but it also serves to improve the flexibility of the cable. In addition, when a large number of small holes are made in the polyethylene tape, the second core wrap layer 2B can also be formed by vertically splicing coating or the like.

As explained above, in the communication cable according to the present invention, a layer of double-sided adhesive laminate tape is provided between the second core wrap layer and the cable sheath to achieve integration between the cable core and the cable sheath. can improve sex. Furthermore, in the present invention, a second core-wrap layer that is adhesive to the laminate tape and has air permeability is provided around the outer periphery of the first core-wrap layer that is air-permeable and has heat-insulating properties. It can be dried without any problem, and can also be bonded to the cable sheath, which is good in terms of productivity.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional communication cable, Figure 2 is a cross-sectional view of a conventional communication cable.
The figure is a cross-sectional view showing an example of the double-sided adhesive laminate tape used in the present invention, FIG. 3 is a cross-sectional view showing an example of the communication cable according to the present invention, and FIG. 4 is a specific implementation of the communication cable according to the present invention. FIG. 3 is a cross-sectional view showing an example. DESCRIPTION OF SYMBOLS 1...Cable core, 2A...First core wrap layer, 2B...Second core wrap layer, 3...Cable sheath, 4...Metal tape, 5, 6...Adhesive layer, 7...Double-sided adhesive laminate tape.

Claims (1)

[Claims] 1. A first core-wrap layer that is breathable and has heat-insulating properties is provided on the outer periphery of the cable core, and has adhesion to the adhesive layer of the double-sided adhesive laminate tape described later on the outer periphery of the first core-wrap layer and has breathable properties. A second core wrap layer having adhesive properties is provided, a layer of double-sided adhesive laminate tape having adhesive layers on both sides of the metal tape is provided on the outer periphery of the second core wrap layer, and a layer of double-sided adhesive laminate tape having adhesive layers on both sides of the metal tape is provided, and a layer of plastic is provided on the outer periphery of the laminate tape layer. What is claimed is: 1. A communication cable comprising: a cable sheath comprising: an inner adhesive layer of said laminate tape being adhered to said second core wrap layer; and an outer adhesive layer of said laminate tape being adhered to said cable sheath.