JP6551763B2 - Coaxial cable and cable using the same - Google Patents

Description

  The present invention relates to a coaxial cable and a cable using the same.

  Conventionally, in the signal line of a medical cable used for medical applications such as ultrasonic diagnosis, a coaxial structure capable of reducing the influence of internal signal leakage and external noise in order to efficiently transmit high frequency signals. Is adopted (see, for example, Patent Document 1).

  In the coaxial structure, in order to reduce the capacitance, a foamed insulator that contains many bubbles and has a lower dielectric constant than a non-foamed insulator that does not contain bubbles is used as the insulator. (See, for example, Patent Document 2).

Unexamined-Japanese-Patent No. 2002-367444 JP, 2011-228064, A JP 2012-104371 A Unexamined-Japanese-Patent No. 5-45729

  By the way, when forming a foam insulator, bubbles are generated in the insulating resin by a pressure enhancement method such as a physical foaming method or a chemical foaming method (see, for example, Patent Document 3), but the diameter of the medical cable is reduced. In the case of using a central conductor having a small outer diameter in order to aim at, the central conductor may not be able to withstand the foaming pressure at the time of bubble generation, and may be damaged or broken.

  In addition, in the pressure enhancement methods such as the physical foaming method and the chemical foaming method, even if an attempt is made to form a thin foam insulation as the diameter of the medical cable is reduced, the bubbles are uniformly dispersed in the insulating resin. It is difficult to form a foamed insulation, and desired electrical characteristics cannot be realized.

  In addition, as a method for forming a foam insulator around the center conductor, a method is also known in which a foam insulation tape is wound around the center conductor to form a foam insulator (see, for example, Patent Document 4). Since the foam insulation tape contains a large number of air bubbles, it tends to be broken starting from the air bubbles due to the winding tension when winding around the center conductor.

  In particular, when a foam insulation tape is wound around a central conductor which is AWG (American Wire Gauge) 48 or less, it is necessary to use a foam insulation tape having a very thin thickness and a very narrow width, as described above, Since the foamed insulating tape is broken by the winding tension, it is almost impossible to wrap the foamed insulating tape around the central conductor to obtain a foamed insulator.

  Therefore, it is an object of the present invention to avoid the damage and breakage of a central conductor even when using a central conductor with a small outer diameter, and to realize a coaxial cable capable of realizing desired electrical characteristics To provide a cable using the

The present invention devised to achieve this object includes a center conductor and an insulator formed around the center conductor, and the insulator is disposed around the center conductor. a void-containing layer having a plurality of voids which are, a reinforcing layer for reinforcing the vacuous layer is disposed between the center conductor and the void-containing layer, Tona is, the gap from the inside of the insulator A coaxial cable having an opening that expands toward the outside of the insulator .

  The void-containing layer is preferably made of polytetrafluoroethylene or polyethylene, and the reinforcing layer is preferably made of polyethylene terephthalate.

  The void-containing layer is preferably penetrated by the void.

  In the void-containing layer, the voids are preferably arranged in a staggered manner at equal intervals.

  The void containing layer is preferably thicker than the reinforcing layer.

Further, the present invention includes a center conductor and an insulator formed around the center conductor, and the insulator has a plurality of gaps arranged around the center conductor. and containing layer, and a reinforcing layer for reinforcing the vacuous layer is disposed between the center conductor and the void-containing layer, Tona is, the gap toward the outside of the insulator from the inside of the insulator It is a cable which has a core unit formed by twisting together a plurality of coaxial cables consisting of an opening which is enlarged accordingly.

  According to the present invention, even when using a central conductor with a small outer diameter, it is possible to prevent damage and breakage of the central conductor and achieve a desired electrical characteristic, and a coaxial cable Cable can be provided.

It is a cross section showing a coaxial cable concerning the present invention. It is a perspective view showing an insulating tape. It is a cross section showing a medical cable concerning the present invention.

  Hereinafter, preferred embodiments of the present invention will be described according to the attached drawings.

  As shown in FIG. 1, a coaxial cable 100 according to a preferred embodiment of the present invention includes a central conductor 101, an insulator 102 formed around the central conductor 101, and a periphery of the insulator 102. A protective body 103 is formed, a shield 104 surrounded by the periphery of the protective body 103, and a jacket 105 formed by the periphery of the shield 104.

  The central conductor 101 constitutes an internal conductor of a coaxial structure, and is formed of a material having high conductivity such as copper or copper alloy, for example, and a single wire on the surface of which silver plating or tin plating is applied. Or it consists of a stranded wire.

  The insulator 102 and the protector 103 constitute an insulator having a coaxial structure, and among these, the insulator 102 has a plurality of gaps 106 formed uniformly distributed at equal intervals on one side. And an insulating tape 107 spirally wound around the center conductor 101 with one side as an outer peripheral surface.

  Thereby, the void ratio of the insulator 102 can be made uniform along the longitudinal direction of the coaxial cable 100, and as a result, the dielectric constant of the insulator 102 becomes uniform along the longitudinal direction of the coaxial cable 100. It is possible to realize desired electrical characteristics in the cable 100.

  The protector 103 suppresses a reduction in the porosity of the insulator 102 due to foreign matters entering the gap 106 or damage to the insulating tape 107, and the protection wound around the insulator 102. It consists of a protective layer that is non-extruded (tube extruded) around the tape or insulator 102.

  The shield 104 constitutes an outer conductor of a coaxial structure, and includes, for example, a braided shield or a horizontally wound shield formed of a material having high conductivity such as copper or copper alloy.

  The jacket 105 is formed of, for example, a resin having high mechanical properties and chemical resistance, such as a fluorine resin, and suppresses deterioration of the electrical properties and the like due to damage to the shield 104.

  The gap 106 is opened toward one surface of the insulating tape 107, and the opening is enlarged toward the surface of the one surface. This is because the outer peripheral surface disposed outside the inner peripheral surface disposed on the inner side when the insulating tape 107 is wound around the center conductor 101 has a longer circumference, and thus the insulating tape 107 serving as the outer peripheral surface. Because one side of is stretched.

  As shown in FIG. 2, it is preferable that the gaps 106 have a round shape and are arranged in a staggered manner at equal intervals.

  As a result, it is possible to prevent the winding tension when the insulating tape 107 is wound around the center conductor 101 from being locally concentrated, and to effectively prevent the insulating tape 107 from being broken during the production of the coaxial cable 100. It is possible to

  The insulating tape 107 includes a gap-containing layer 108 having a thickness of about 25 μm or less in which the gap 106 is formed, a reinforcing layer 109 having a thickness of about 5 μm or less, which is thermally fused to the gap-containing layer 108, And the overall thickness is about 30 μm or less.

  The void containing layer 108 is formed of a material having a low dielectric constant such as polytetrafluoroethylene or polyethylene, and the reinforcing layer 109 is formed of a material having a high mechanical strength such as polyethylene terephthalate.

  Among these, the reinforcing layer 109 is particularly preferably formed of super-stretched polyethylene terephthalate having a tensile strength of about 400 MPa.

  Thereby, even if the thickness of the reinforcing layer 109 is about 5 μm or less, it is possible to sufficiently suppress the stretching or breakage of the void-containing layer 108 due to the winding tension when the insulating tape 107 is wound around the central conductor 101. Therefore, it is possible to contribute to reducing the diameter of the coaxial cable 100.

  The insulating tape 107 is embossed or punched by embossing or punching a low dielectric constant sheet made of a material having a low dielectric constant such as polytetrafluoroethylene or polyethylene to form embossed or penetrating holes. The low dielectric constant sheet in which the holes are formed and the reinforcing sheet formed of a material having high mechanical strength such as polyethylene terephthalate are thermally fused and attached to be integrated to form an insulating sheet, and then the insulating sheet is formed. Cut to the desired width and length to make.

  As a result, the embossed or through hole becomes a bottomed concave void 106 and the void-containing layer 108 having the void 106 is reinforced by the reinforcing layer 109. Therefore, when the insulating tape 107 is wound around the central conductor 101 Thus, the void containing layer 108 is stretched by the winding tension to suppress the void 106 from being crushed, and it is possible to suppress the void containing layer 108 from being broken starting from the void 106 having weak mechanical strength.

  Note that the void 106 formed through the punching process has a larger volume as the void 106 than the void 106 formed through the embossing process. Therefore, the porosity of the insulator 102 is increased to increase the porosity of the insulator 102. In order to reduce the dielectric constant, it is preferable that the void 106 formed through punching be adopted, and the void-containing layer 108 be penetrated by the void 106.

  Further, the air gap 106 may be a groove type. However, it is more preferable that the void 106 has a round shape because the low dielectric sheet with embossed and through holes formed therein is integral and does not separate, and thus the low dielectric sheet and the reinforcing sheet can be easily attached. .

  Therefore, according to the coaxial cable 100 according to the present embodiment, even if the central conductor 101 having a small outer diameter is used to reduce the diameter of the coaxial cable 100, a foamed insulator is used as the insulator 102. Therefore, the central conductor 101 can be prevented from being damaged or broken.

  Moreover, according to the coaxial cable 100 according to the present embodiment, the thin insulating tape 107 is used for the purpose of forming the thin insulator 102 as the coaxial cable 100 is made thinner. Even in this case, since the voids 106 are uniformly present in the void-containing layer 108, desired electrical characteristics can be realized.

  Furthermore, in the coaxial cable 100 according to the present embodiment, the thin insulating tape 107 is used for the purpose of forming the thin insulator 102 as the coaxial cable 100 is reduced in diameter. Even if the insulating tape 107 is reinforced by the reinforcing layer 109, the insulating tape 107 is not easily broken by the winding tension when the insulating tape 107 is wound around the center conductor 101.

  Therefore, according to the coaxial cable 100 according to the present embodiment, even when the insulating tape 107 is wound around the central conductor 101 that is AWG (American Wire Gauge) 48 or less, the insulating tape 107 does not break. The insulating tape 107 can be wound around the central conductor 101 to form the insulator 102.

  As shown in FIG. 3, a plurality of core wire units 200 formed by twisting a plurality of coaxial cables 100 are bundled by, for example, a bind tape 301, a braided shield 302, a sheath 303, etc. It can also be used as the cable 300. As a result, the diameter of the medical cable 300 can be reduced.

  As described above, according to the present invention, even when the central conductor 101 having a small outer diameter is used, damage or breakage of the central conductor 101 can be avoided and desired electrical characteristics can be realized. The coaxial cable 100 and a cable using the same can be provided.

DESCRIPTION OF SYMBOLS 100 coaxial cable 101 center conductor 102 insulator 103 protector 104 shield 105 jacket 106 air gap 107 insulating tape 108 air gap containing layer 109 reinforcing layer 200 core unit 300 medical cable

Claims (6)

A central conductor;
An insulator formed around the central conductor;
Equipped with
The insulator includes a void-containing layer having a plurality of voids disposed around the central conductor, and a reinforcing layer disposed between the central conductor and the void-containing layer to reinforce the void-containing layer. Do Ri, coaxial cable, characterized in that it consists of opening the gap is expanded to bring the outward of the insulator from the inside of the insulator. The coaxial cable according to claim 1 , wherein the void containing layer is formed of polytetrafluoroethylene or polyethylene, and the reinforcing layer is formed of polyethylene terephthalate. The void-containing layer, the coaxial cable according to claim 1 or 2 is penetrated by the air gap. The coaxial cable according to any one of claims 1 to 3 , wherein the void-containing layers are arranged in a staggered manner at equal intervals in each of the voids. The coaxial cable according to any one of claims 1 to 4 , wherein the void containing layer is thicker than the reinforcing layer. A central conductor, and an insulator formed around the central conductor, wherein the insulator has a plurality of voids disposed around the central conductor, and the center. a reinforcing layer for reinforcing the vacuous layer disposed between the conductor and the void-containing layer, Ri Tona, the gap is expanded to bring the outward of the insulator from the inside of the insulator A cable comprising a core unit formed by twisting a plurality of coaxial cables each having an opening .

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