JP2005174598A - High frequency coaxial cable - Google Patents

Abstract

A high-frequency coaxial cable excellent in shielding performance is provided.
A high frequency coaxial cable includes an inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, and an outer periphery of the outer conductor. And a covered sheath 11. In addition, the outer conductor 25 has a single or multiple structure including a laminate tape 19 in which metal layers 15 and 17 are bonded to both surfaces of the resin layer 13, and the laminate tape 19 is bonded to the insulator 5 by an adhesive layer 21. It is stuck on the outer periphery. Further, the surfaces of the metal layers 15 and 17 on one end side in the circumferential direction of the laminate tape 19 are provided with surfaces of the metal layers 15 and 17 extending in the circumferential direction from the position of the adhesive layer 21 on the other end side of the laminate tape 19. Overlapped polymerized portions 23 are provided. Even if the coaxial cable 1 is bent, no gap is generated in the overlapping portion 23.
[Selection] Figure 1

Description

  The present invention relates to a high-frequency coaxial cable, and more particularly, to a high-frequency coaxial cable excellent in shielding performance used for television broadcasting.

  Referring to FIGS. 7A, 7B, and 7C, conventionally, a high-frequency coaxial cable 101 for television broadcasting generally has an inner conductor 103 and an insulation covering the outer periphery of the inner conductor 103. Body 105, first outer conductor 107 vertically provided on the outer periphery of insulator 105, second outer conductor 109 provided on the outer periphery of first outer conductor 107, and outer periphery of second outer conductor 109 And a sheath 111 covered with

  For example, the inner conductor 103 is made of annealed copper wire, the insulator 105 is made of foamed polyethylene, and the first outer conductor 107 is a laminate tape in which aluminum foils 115 and 117 are attached to both surfaces of a plastic tape 113, and the second outer conductor The conductor 109 is a braid of tinned annealed copper wire, and the sheath 111 is polyvinyl chloride (PVC). The cable 101 having the above structure is referred to as an “FB coaxial cable”.

  Further, the first outer conductor 107 of the laminate tape composed of the aluminum foil 115, the plastic tape 113, and the aluminum foil 117 is vertically attached as shown in the VII part of FIG. 7B and FIG. 7C. In this overlapping portion 119, the aluminum foil 117 of the inner laminate tape and the aluminum foil 115 of the outer laminate tape are in electrical contact. However, when the cable 101 is bent, the laminate tape outside the radius of curvature of the bend is excessively pulled inside the radius of curvature and a gap is formed in the overlapped portion 119, so that the amount of transmission signal leakage increases. There was a problem.

  Therefore, although not shown as another conventional high-frequency coaxial cable, as the overlapping portion 119 of the first outer conductor 107, the remaining first outer conductor 107 is vertically attached to the outer periphery of the insulator 105. The inner peripheral surfaces on both ends are overlapped and folded so as to be in contact with each other, and at least a part of the overlapping portion of the folded portion is bonded in the longitudinal direction (see, for example, Patent Document 1).

  Referring to FIG. 8, another conventional high-frequency coaxial cable 121 is a high-frequency coaxial cable having substantially the same structure as that in FIG. 7, and the aluminum foil 115 on the insulator 105 side of the laminate tape of the first outer conductor 107. Is provided with an adhesive layer 123, and the insulator 105 and the first outer conductor 107 are adhered to each other so that no gap is formed in the overlapped portion 119 of the laminate tape.

  Referring to FIG. 9, another conventional high-frequency coaxial cable 125 is a cable having substantially the same structure as that in FIG. 7, and the first outer conductor 107 has an aluminum foil 117 attached to one side of the plastic tape 113. This is a laminate tape, and an adhesive layer 123 is provided on the plastic tape 113 of the laminate tape, and the insulator 105 and the first outer conductor 107 are adhered to each other so that no gap is formed in the overlapped portion 119 of the laminate tape. Yes.

As another conventional high-frequency coaxial cable, the outer conductor is a metal tape, and this metal tape surrounds the periphery of a cylindrical insulating layer (corresponding to the above-mentioned insulator) and overlaps the edge portion of the cable. A seam portion formed in the longitudinal direction is provided, and the metal tape is fixed to an inner surface of an outer jacket (corresponding to the above-described sheath) through an adhesive layer, and a metal is provided on an overlapping portion of the seam portion of the metal tape. A direct contact portion between the tapes and an adhesive portion obtained by adhering the metal tapes with an adhesive layer are provided (for example, see Patent Document 2).
JP 2002-352639 A JP 47-35885 A

  By the way, in the prior art, in the high-frequency coaxial cable 101 having the structure of FIG. 7, as described above, when the cable 101 is bent, a gap is generated in the overlapped portion 119, so that the amount of transmission signal leakage increases. There was a problem that.

  In addition, the high-frequency coaxial cable of Patent Document 1 has an overlapped portion of the folded portion, and a part of the overlapped portion is bonded in the longitudinal direction. There was a problem of requiring a lot.

  Further, in the high-frequency coaxial cables 121 and 125 having the structure shown in FIGS. 8 and 9, since the adhesive layer 123 is not conductive or has low conductivity, the adhesive layer of the overlapping portion 119 of the laminated tape of the first outer conductor 107 is used. Since there is no electrical contact at 123, the transmission signal in the coaxial cable leaks.

  In addition, the high-frequency coaxial cable of Patent Document 2 has a problem that the outer conductor is a metal tape and is heavy, and cannot be thinned in consideration of the load applied when the cable is bent. In addition, since the overlapping portion of the metal tape is bonded with an adhesive layer, if a cable bending load is applied to the overlapping portion, the thin metal tape will break.

  The present invention has been made to solve the above-described problems.

  The high-frequency coaxial cable of the present invention includes an inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, and a sheath covering the outer periphery of the outer conductor. In the high-frequency coaxial cable, the outer conductor is configured with one or multiple structures including a laminate tape in which a first metal layer and a second metal layer are bonded to both surfaces of a resin layer, and the surface of the first metal layer of the laminate tape Is adhered to the outer periphery of the insulator by an adhesive layer, and is extended in the circumferential direction from the position of the adhesive layer on the other end side of the laminate tape on the surface of the second metal layer on the one end side in the circumferential direction of the laminate tape. A superposed portion where the surfaces of the first metal layer are overlapped is provided.

  In the high-frequency coaxial cable according to the present invention, in the high-frequency coaxial cable, a second metal layer extending in a circumferential direction from a position of the first metal layer and the resin layer of the laminate tape outside the overlap portion is provided on the inside of the overlap portion. It is preferable to provide the 2nd superposition | polymerization part superimposed on the surface of the 2nd metal layer of the laminate tape.

  In the high-frequency coaxial cable according to the present invention, in the high-frequency coaxial cable, the surface of the first metal layer of the laminate tape is adhered to the outer periphery of the insulator with an adhesive layer, and the superposed portion is formed on the laminate tape on the one end side. An extension portion is provided by extending the first metal layer in the circumferential direction from the position of the resin layer and the second metal layer, and the first metal layer of the laminate tape on the other end side is provided on the surface of the first metal layer of the extension portion. A first superposed portion having a superposed surface is provided, and a second metal layer extending in a circumferential direction from the position of the first metal layer and the resin layer of the laminate tape outside the first superposed portion is provided on the laminate tape on the one end side. It is preferable to provide a second polymerization portion superimposed on the surface of the second metal layer.

  The high-frequency coaxial cable of the present invention includes an inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, and a sheath covering the outer periphery of the outer conductor. In the high-frequency coaxial cable, the outer conductor is configured with one or multiple structures including a laminate tape in which a metal layer is bonded to one side of the resin layer, and the resin layer side of the laminate tape is attached to the outer periphery of the insulator by an adhesive layer. A superposed portion in which a metal layer extended in the circumferential direction from the position of the adhesive layer and the resin layer on the other end side of the laminate tape is superposed on the surface of the metal layer on one end side in the circumferential direction of the laminate tape while being stuck Is provided.

  As can be understood from the means for solving the above-described problems, according to the present invention, on the other side of the laminate tape except for the superposed portion, the surface of the metal layer is substantially the entire outer periphery of the insulator via the adhesive layer. Therefore, moisture can be prevented from entering between the insulator and the laminate tape, and attenuation of the transmission signal due to the wetting can be prevented. Furthermore, even if the coaxial cable is bent, there is no phenomenon that a gap is generated in the overlapped portion because the laminate tape moves in accordance with the bending. Moreover, even if the polymerized portion is located at the bent portion, the metal layers of the polymerized portions are simply overlapped and electrically contacted to each other so that the degree of freedom is large, so that the expansion and contraction elongation does not concentrate. Will not break. Therefore, even if the coaxial cable is bent, the amount of transmission signal leakage does not increase at the overlapped portion.

  In addition, the present invention can be applied to all high-frequency coaxial cables having a laminate tape in which a metal layer is bonded to one or both sides of a resin layer as an external conductor. That is, the outer conductor can be applied to one or multiple structures including at least a laminate tape.

  Embodiments of the present invention will be described below with reference to the drawings.

  Referring to FIGS. 1A, 1B, and 1C, a high-frequency coaxial cable 1 according to the first embodiment includes an inner conductor 3 and an insulator 5 that covers the outer periphery of the inner conductor 3. The first outer conductor 7 provided vertically on the outer periphery of the insulator 5, the second outer conductor 9 provided on the outer periphery of the first outer conductor 7, and the outer periphery of the second outer conductor 9 are covered. And a sheath 11.

  For example, the inner conductor 3 is made of annealed copper wire, the insulator 5 is made of foamed polyethylene, and the first outer conductor 7 is, for example, an aluminum foil 15 as a first metal layer on both sides of a plastic tape 13 as a resin layer. For example, a laminate tape 19 with an aluminum foil 17 as a second metal layer is pasted, and the surface of the aluminum foil 15 of the laminate tape 19 is vertically attached to the outer periphery of the insulator 5 via an adhesive layer 21. Has been. The second outer conductor 9 is a braid of tinned annealed copper wire, and the sheath 11 is polyvinyl chloride (PVC).

  Furthermore, as shown in FIG. 1B and I portion of FIG. 1B, the laminate tape 19 has one end side in the circumferential direction of the laminate tape 19 (left side in FIG. 1C). On the surface of the aluminum foil 17, a superposed portion 23 is provided in which the surface of the aluminum foil 15 on the other end side in the circumferential direction of the laminate tape 19 (on the right side in FIG. 1C) is overlapped. That is, since the adhesive layer 21 is not provided on the surface of the aluminum foil 15 of the outer laminate tape 19 in the superposed portion 23, the aluminum foil 17 of the inner laminate tape 19 and the outer laminate tape 19 are used in the superposed portion 23. The aluminum foil 15 is in electrical contact.

  In this embodiment, the outer conductor 25 is composed of the first outer conductor 7 and the second outer conductor 9, and the outer conductor 25 includes one or more of the first outer conductors 7 that are the laminate tape 19. It may be a multiple structure.

  With the above configuration, since the surface of the aluminum foil 15 is bonded to almost the entire outer periphery of the insulator 5 through the adhesive layer 21 on the other surface of the laminate tape 19 except the superposed portion 23, the insulator 5 and the laminate tape In addition to preventing moisture from entering between the two, the transmission signal can be prevented from being attenuated due to the wetness, and even when the high-frequency coaxial cable 1 is bent, the laminate tape 19 moves according to the bending. Thus, the phenomenon that the laminate tape 19 outside the bending radius of curvature is excessively pulled inside the curvature radius and a gap is formed in the overlapped portion 23 is eliminated.

  Moreover, even if the overlapped portion 23 is located at the bent portion, the aluminum foil 17 and the aluminum foil 15 of the overlapped portion 23 have a large degree of freedom simply by being overlaid and in electrical contact with each other. Therefore, the aluminum foil 17 and the aluminum foil 15 are not broken. Therefore, even if the high-frequency coaxial cable 1 is bent, the amount of leakage of the transmission signal does not increase at the overlapping portion.

  Referring to FIG. 2, the overall structure of the high-frequency coaxial cable 27 of the second embodiment is substantially the same as that of the high-frequency coaxial cable 1 of the first embodiment. To explain. Only the structure in the vicinity of the portion where the first outer conductors 7 are overlapped will be described as a different point, and the others are the same.

  Similar to the first embodiment, the first outer conductor 7 is a laminate tape 19 in which, for example, an aluminum foil 15 as a first metal layer and an aluminum foil 17 as a second metal layer are attached to both surfaces of a plastic tape 13. The surface of the aluminum foil 15 of the laminate tape 19 is vertically attached to the outer periphery of the insulator 5 via the adhesive layer 21.

  Further, the laminate tape 19 is disposed on the surface of the aluminum foil 17 on one end side in the circumferential direction of the laminate tape 19 (left side in FIG. 2) and on the other end side in the circumferential direction of the laminate tape 19 (right side in FIG. 2). A first overlapping portion 29 in which the surfaces of the aluminum foil 15 are overlapped is provided. Further, the first overlapping portion 29 is provided with an extended portion in which the aluminum foil 17 of the outer laminate tape 19 extends in the circumferential direction (left direction in FIG. 2) from the positions of the plastic tape 13 and the aluminum foil 15; A second overlapping portion 31 is provided in which the aluminum foil 17 of the extended portion is superimposed on the surface of the aluminum foil 17 of the inner laminate tape 19.

  Accordingly, the aluminum foil 17 of the inner laminate tape 19 and the aluminum foil 15 of the outer laminate tape 19 are in electrical contact with each other at the first overlap portion 29, and further, the inner laminate tape 19 is at the second overlap portion 31. The aluminum foil 17 and the aluminum foil 17 of the outer laminate tape 19 are in electrical contact.

  Referring to FIG. 3, the high-frequency coaxial cable 33 of the third embodiment has an overall structure that is substantially the same as that of the high-frequency coaxial cable 1 of the first embodiment. To explain. Only the structure in the vicinity of the overlapped portion of the first outer conductor 7 will be described as a different point, and the others are the same.

  Similar to the first embodiment, the first outer conductor 7 is a laminate tape 19 in which, for example, an aluminum foil 15 as a first metal layer and an aluminum foil 17 as a second metal layer are attached to both surfaces of a plastic tape 13. The surface of the aluminum foil 15 of the laminate tape 19 is vertically attached to the outer periphery of the insulator 5 via the adhesive layer 21.

  Further, in the laminate tape 19, the aluminum foil 15 on one end side (left side in FIG. 3) in the circumferential direction of the laminate tape 19 extends in the circumferential direction (right direction in FIG. 3) from the position of the plastic tape 13 and the aluminum foil 17. An extended portion 35 is provided. A first overlapping portion 37 is provided on the surface of the aluminum foil 15 of the extended portion 35 by overlapping the surface of the aluminum foil 15 on the other end side in the circumferential direction of the laminate tape 19 (right side in FIG. 3). Further, the first overlapping portion 37 is provided with an extended portion 39 in which the aluminum foil 17 of the outer laminate tape 19 extends in the circumferential direction (left direction in FIG. 3) from the positions of the plastic tape 13 and the aluminum foil 15. A second overlapping portion 41 is provided in which the aluminum foil 17 of the extended portion 39 is superposed on the surface of the aluminum foil 17 of the inner laminate tape 19.

  Therefore, in the 1st superposition | polymerization part 37, the aluminum foil 15 of the laminating tape 19 of the one end side and the aluminum foil 15 of the laminating tape 19 of the other end side are electrically contacting, Furthermore, in the 2nd superposition | polymerization part 41, one end side The aluminum foil 17 of the laminate tape 19 and the aluminum foil 17 of the laminate tape 19 on the other end side are in electrical contact.

  Referring to FIG. 4, the overall structure of the high-frequency coaxial cable 43 of the fourth embodiment is substantially the same as that of the high-frequency coaxial cable 1 of the first embodiment. To explain. Only the structure of the first outer conductor 7 and the structure in the vicinity of the portion where the first outer conductor 7 are overlapped will be described as different points, and the rest is the same.

  The first outer conductor 7 is a laminate tape 45 in which, for example, an aluminum foil 17 as a metal layer is attached to one surface of the plastic tape 13, and the surface of the plastic tape 13 of the laminate tape 45 is connected to the above insulator via the adhesive layer 21. Attached vertically to the outer periphery of 5.

  Further, the laminate tape 45 is disposed on the surface of the aluminum foil 17 on one end side (left side in FIG. 4) of the laminate tape 45 on the other end side (right side in FIG. 4) of the laminate tape 45 in the circumferential direction. A superposed portion 47 is provided in which the aluminum foil 17 of an extended portion extending in the circumferential direction (left direction in FIG. 4) from the positions of the plastic tape 13 and the adhesive layer 21 is overlapped.

  Therefore, in the superposed portion 47, the aluminum foil 17 of the laminate tape 45 on one end side and the aluminum foil 17 of the laminate tape 45 on the other end side are in electrical contact.

  As described above, the examples of FIGS. 2, 3 and 4 also have the same effects as those of FIG.

  Referring to FIG. 5, there are shown measurement result examples of the shielding attenuation measured by the triaxial method of IEC 61196-1 for the high-frequency coaxial cables of the first to fourth embodiments described above. Further, as a comparative example, a measurement result example of the shielding attenuation amount measured also for the conventional high-frequency coaxial cable 121 shown in FIG. 8 is shown.

  In this measurement method, as shown in FIG. 6, the ratio (dB) between the transmission signal input to the coaxial cable 49 and the transmission signal leaking from the outer conductor 51 of the coaxial cable 49 is measured. is there.

  One end side (right side in FIG. 6) of the coaxial cable 49 as a sample has a length of about 2 m as a coupling length in the insertion hole 55 provided in the left end wall of the first copper pipe 53 whose left end is closed in FIG. Only inserted. In the inserted coaxial cable 49, the outer conductor 51 is conducted through the insertion hole 55 of the first copper pipe 53 at a location where the sheath 11 is partially removed. An output portion 57 is provided at the other end of the first copper pipe 53. Further, inside the first copper pipe 53, the outer conductor 51 at one end of the inserted coaxial cable 49 is electrically connected to the second copper pipe 59, and the inner conductor 3 is provided at the end provided in the second copper pipe 59. After passing through the resistor 61, it is conducted to the output portion 57 at the other end of the first copper pipe 53.

  Therefore, when a transmission signal is input to the coaxial cable 49 from the left input portion 63 in FIG. 6 and leaks from the coaxial cable 49 inside the first copper pipe 53, the leakage occurs at the output portion 57 of the first copper pipe 53. Since the incoming transmission signal is detected, the ratio of the input signal to the output signal is measured.

  The graph of FIG. 5 is an approximate display of asymptotic lines of measurement values obtained by the measurement method described above. As can be seen from a comparison between the conventional high-frequency coaxial cable 121 and the high-frequency coaxial cables 1, 27, 33, 43 of the first to fourth embodiments, the structure of this embodiment is the conventional high-frequency coaxial cable. It can be confirmed that the cable 121 has better shielding properties. The electrical characteristics such as attenuation and the manufacturability of the cable are equivalent to the conventional high-frequency coaxial cable 121 and are excellent.

  In the first to fourth embodiments described above, the first outer conductor 7 and the second outer conductor 9 are provided as the outer conductor 25, but only the first outer conductor 7 may be provided. Or, conversely, a multiple structure including the first outer conductor 7 may be employed. In addition, the first outer conductor 7 is a laminate tape in which a metal layer is adhered to both surfaces of the plastic tape 13, but may be a laminate tape in which a metal layer is adhered to one surface of the plastic tape 13. That is, the high-frequency coaxial cable according to the embodiment of the present invention can be applied to all high-frequency coaxial cables provided with the laminated tape having the metal layer attached to both surfaces or one surface of the plastic tape 13 as the first outer conductor 7. is there. For example, the application can be applied to various applications including television. Further, the same effect can be obtained even when the plastic tape 13 has a horizontal winding structure.

  In addition, this invention is not limited to embodiment mentioned above, It can implement in another aspect by making an appropriate change.

(A) is a side view of the high-frequency coaxial cable according to the first embodiment of the present invention, (B) is a cross-sectional view of (A), and (C) is a partially enlarged cross section of an I part of (B). FIG. It is a high-frequency coaxial cable according to the second embodiment of the present invention, and is a partial enlarged cross-sectional view of a position corresponding to a portion I in FIG. It is a high-frequency coaxial cable according to a third embodiment of the present invention, and is a partial enlarged cross-sectional view of a position corresponding to a portion I in FIG. It is a high frequency coaxial cable of 4th Embodiment of this invention, Comprising: It is a partial expanded sectional view of the position applicable to the I section of FIG. 1 (B). It is a graph of the measurement result of the shielding attenuation amount in the high frequency coaxial cable of the 1st-4th embodiment and the conventional high frequency coaxial cable. It is a schematic explanatory drawing which shows the shielding attenuation amount measuring method. (A) is a side view of a conventional high-frequency coaxial cable, (B) is a cross-sectional view of (A), and (C) is a partially enlarged cross-sectional view of a VII portion of (B). (A) is sectional drawing of the other conventional high frequency coaxial cable, (B) is a partial expanded sectional view of the VIII part of (A). It is another conventional high frequency coaxial cable, Comprising: It is a partial expanded sectional view of the position applicable to the VIII part of FIG. 8 (B).

Explanation of symbols

1 High-frequency coaxial cable (of the first embodiment)
3 Inner conductor 5 Insulator 7 First outer conductor 9 Second outer conductor 11 Sheath 13 Plastic tape (resin layer)
15 Aluminum foil (first metal layer)
17 Aluminum foil (second metal layer)
19 Laminate tape 21 Adhesive layer 23 Superposition part 25 High frequency coaxial cable (of the second embodiment)
27 First overlapping portion 29 Second overlapping portion 31 High-frequency coaxial cable (of the third embodiment)
33 Extension portion 35 First overlapping portion 37 Extension portion 39 Second overlapping portion 41 High-frequency coaxial cable (of the fourth embodiment)
43 Laminate tape 45 Polymerized part

Claims (4)

In a high-frequency coaxial cable comprising an inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, and a sheath covering the outer periphery of the outer conductor,
The outer conductor is configured with one or multiple structures including a laminate tape in which a first metal layer and a second metal layer are bonded to both surfaces of a resin layer, and the surface of the first metal layer of the laminate tape is formed by an adhesive layer. A first metal layer attached to the outer periphery of the insulator and extending in the circumferential direction on the surface of the second metal layer on one end side in the circumferential direction of the laminate tape from the position of the adhesive layer on the other end side of the laminate tape A high-frequency coaxial cable, characterized in that a superposed portion is formed by superimposing the surfaces.   A second metal layer extending in the circumferential direction from the position of the first metal layer and the resin layer of the laminate tape outside the polymer portion was superimposed on the surface of the second metal layer of the inner laminate tape on the polymerized portion. The high frequency coaxial cable according to claim 1, wherein a second overlapping portion is provided.   The surface of the first metal layer of the laminate tape is adhered to the outer periphery of the insulator with an adhesive layer, and the polymerized portion is positioned between the resin layer and the second metal layer of the first metal layer of the laminate tape on the one end side. An extended portion extending in the circumferential direction is provided, and a first overlapping portion is provided on the surface of the first metal layer of the extended portion so that the surface of the first metal layer of the laminate tape on the other end is overlapped. A second polymerization in which a first metal layer and a second metal layer extending in the circumferential direction from the position of the resin layer on the outer side of the one polymerization portion are superposed on the surface of the second metal layer of the laminate tape on the one end side. The high-frequency coaxial cable according to claim 1, wherein a portion is provided. In a high-frequency coaxial cable comprising an inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, and a sheath covering the outer periphery of the outer conductor,
The outer conductor is composed of one or multiple structures including a laminate tape in which a metal layer is adhered to one side of a resin layer, and the surface of the resin layer of the laminate tape is adhered to the outer periphery of the insulator with an adhesive layer, A superposition portion is provided on the surface of the metal layer on one end side in the circumferential direction of the laminate tape, and a superposed metal layer extending in the circumferential direction from the position of the adhesive layer and the resin layer on the other end side of the laminate tape is provided. High frequency coaxial cable.

Images