JP2015005440A - Differential transmission cable and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential transmission cable which can inhibit the generation of a cavity between an insulator and a conductive shield layer and a method of producing the same.SOLUTION: This invention provides a differential transmission cable at least comprising two inner conductors 2, an insulator 3 provided to collectively cover the two inner conductors 2, and a conductive shield layer 4 provided on the outer periphery of the insulator 3. The conductive shield layer 4 is made of a seamless metal layer that closely contacts with the outer periphery of the insulator 3.

Description

  The present invention relates to a differential transmission cable and a method for manufacturing the same.

  As a differential transmission cable for high-speed transmission, two inner conductors, an insulator provided so as to cover the two inner conductors at once, and a conductive shield layer (external) provided on the outer periphery of the insulator And a conductor) are known.

  In the conventional differential transmission cable, the conductive shield layer is made of a metal tape. More specifically, the conductive shield layer is formed by vertically wrapping metal tape around the outer periphery of the insulator, spirally winding the metal tape around the outer periphery of the insulator, or sandwiching the insulator from above and below with the metal tape. Configured.

  In the conventional differential transmission cable, a presser winding tape is generally wound around the outer periphery of the conductive shield layer so that the metal tape does not loosen.

  As prior art document information related to the invention of this application, there are Patent Documents 1 and 2.

Special table 2008-542999 gazette JP 2012-169251 A

  However, in the conventional differential transmission cable using a metal tape for the conductive shield layer, a gap (gap) is easily generated between the insulator and the conductive shield layer, and the characteristics such as skew deteriorate due to this gap. There was a problem that.

  Accordingly, an object of the present invention is to provide a differential transmission cable and a method for manufacturing the same that can solve the above-described problems and can suppress the generation of a gap between an insulator and a conductive shield layer.

  The present invention has been devised to achieve the above object, and includes at least two inner conductors, an insulator provided so as to collectively cover the two inner conductors, and the insulator. A differential transmission cable including a conductive shield layer provided on an outer periphery, wherein the conductive shield layer is a differential transmission cable made of a seamless metal layer in close contact with the outer periphery of the insulator.

  The present invention also includes at least two inner conductors, an insulator provided so as to collectively cover the two inner conductors, and a conductive shield layer provided on the outer periphery of the insulator; A method for manufacturing a differential transmission cable comprising a differential transmission cable, wherein the conductive shield layer made of a seamless metal layer in close contact with the outer periphery of the insulator is provided on the outer periphery of the insulator by extrusion of a metal sheath. It is a manufacturing method of a cable.

  While feeding the two inner conductors collectively covered with the insulator as a core wire into a metal sheath extruder, supplying a metal material as an extruded material, and extruding the extruded material around the core wire, The conductive shield layer may be formed by forming a metal pipe apart from the core wire and molding the metal pipe according to the outer shape of the core wire with a molding die.

  The molding die may be provided with a cooling means for cooling the metal pipe.

  The cooling means may include a cooling water circulation path formed so as to pass through the inside of the molding die, and a cooling water circulation means for circulating cooling water through the cooling water circulation path.

  ADVANTAGE OF THE INVENTION According to this invention, the differential transmission cable which can suppress that a space | gap arises between an insulator and an electroconductive shield layer, and its manufacturing method can be provided.

It is a cross-sectional view of a differential transmission cable according to an embodiment of the present invention. It is a figure which shows the manufacturing apparatus of the differential transmission cable used for the manufacturing method of the differential transmission cable which concerns on one embodiment of this invention, (a) is a longitudinal cross-sectional view, (b) is the 2B-2B sectional view taken on the line It is. It is a principal part enlarged view of Fig.2 (a).

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a differential transmission cable according to the present embodiment.

  As shown in FIG. 1, the differential transmission cable 1 includes at least two inner conductors 2 arranged in parallel, and an insulator 3 provided so as to collectively cover the two inner conductors 2; And a conductive shield layer (external conductor) 4 provided on the outer periphery of the insulator 3.

  In the differential transmission cable 1 according to the present embodiment, the conductive shield layer 4 is made of a seamless metal layer that is in close contact with the outer periphery of the insulator 3. Here, “close contact” refers to a state of close contact, and “seamless” refers to a continuous structure with no seam in any of the circumferential direction, longitudinal direction, and thickness direction. Means.

  The conductive shield layer 4 is formed by metal sheath extrusion. In the metal sheath extrusion, the two inner conductors 2 collectively covered with the insulator 3 are supplied as the core wire 5, and the conductive shield layer 4 is formed around the core conductor 5. The conductive shield layer 4 is made of, for example, copper, a copper alloy, or aluminum.

  Although not shown, an insulating layer may be formed on the outer periphery of the conductive shield layer 4. In the differential transmission cable 1, it is possible to omit a presser winding tape that is essential when a metal tape is used for the conductive shield layer 4. For example, a sheath is directly attached to the outer periphery of the conductive shield layer 4 by extrusion molding. It is also possible to form.

  Next, a method for manufacturing the differential transmission cable according to the present embodiment will be described. First, a differential transmission cable manufacturing apparatus used in the differential transmission cable manufacturing method according to the present embodiment will be described.

  As shown in FIGS. 2 and 3, the differential transmission cable manufacturing apparatus 21 is a rotating wheel type metal sheath extruder, and a rotating wheel 22 causes a die (die) 23 and a core (nipple) 24 to be interposed between them. The extrusion material 25 is supplied, and the extrusion material 25 is continuously extruded from the gap between the base 23 and the core metal 24.

  Although not shown, the rotary wheel 22 is attached to the main body frame and is configured to be rotationally driven by a drive source. Two grooves 26 are formed along the circumferential direction of the rotating wheel 22, and a metal material (metal wire) supplied as the extruded material 25 is accommodated in the grooves 26. The extruded material 25 is supplied from the tangential direction of the rotating wheel 22 and is supplied to the base 23 as the rotating wheel 22 rotates.

  The base 23 is defined by a die chamber 27. The die chamber 27 is attached to a case 29 attached to the main body frame so as to be rotatable around a shaft 28.

  The case 29 is provided with a heater 30 for heating the die chamber 27 so as to surround the die chamber 27. In addition, an abutment 31 that dams the extruded material 25 and guides it to the die chamber 27 is attached to the case 29.

  Further, the case 29 is provided with a molding die 33 for molding the extruded material 25 (a metal pipe 32 described later) extruded from the gap between the base 23 and the core metal 24 according to the outer shape of the core wire 5. .

  The molding die 33 is provided with a cooling means 34 for cooling the extruded material 25 (metal pipe 32) extruded from the gap between the base 23 and the core metal 24.

  In the present embodiment, the cooling means 34 includes: a cooling water circulation path 35 formed so as to pass through the inside of the molding die 33; and a cooling water circulation means such as a pump (not shown) that circulates the cooling water in the cooling water circulation path 35. Become. That is, the molding die 33 is a cooling water jacket type, and is maintained at a substantially constant temperature.

  In the method for manufacturing a differential transmission cable according to the present embodiment, a conductive shield layer made of a seamless metal layer is formed on the outer periphery of the insulator 3 by extrusion of a metal sheath using the differential transmission cable manufacturing apparatus 21 of FIG. 4 is provided.

  First, the two inner conductors 2 collectively covered with the insulator 3 as the core wire 5 are fed into the cored bar 24 of the differential transmission cable manufacturing apparatus 21, and the metal as the extruded material 25 is inserted into the groove 26 of the rotating wheel 22. Supply material (metal wire).

  The extruded material 25 is fed along with the rotation of the rotating wheel 22, stopped by the abutment 31, and continuously supplied to the die chamber 27 one after another. At this time, the extruded material 25 is in a semi-molten state at high temperature and high pressure due to the pressure to be pushed in, the heat generated from the plastic deformation, and the heating of the heater 30. The extruded material 25 in the semi-melted state is pushed out from the gap between the base 23 and the cored bar 24.

  The extruded material 25 pushed out from the gap between the base 23 and the core metal 24 is pushed out around the core wire 5 fed into the core metal 24. At this time, since the extruded material 25 has a high temperature of, for example, 400 ° C. to 600 ° C., when the extruded material 25 immediately after extrusion is brought into contact with the core wire 5, the insulator 3 is melted. Therefore, in the present embodiment, the extruded material 25 is extruded away from the core wire 5. A seamless metal pipe 32 is formed around the core wire 5 so as to be separated from the core wire 5.

  Thereafter, the core wire 5 and the metal pipe 32 are introduced into the molding die 33, and the metal pipe 32 is molded according to the outer shape of the core wire 5 by the molding die 33. The metal pipe 32 is cooled until reaching the molding die 33 and further reduced in diameter while being cooled by the cooling means 34 of the molding die 33 (cooling water circulating through the cooling water circulation path 35). At this time, in order to suppress the deformation of the insulator 3 due to heat, the cooling degree of the cooling means 34 and the position of the molding die 33 (distance from the base 23) so that the temperature of the metal pipe 32 is 100 ° C. or less. It is good to adjust.

  As described above, the conductive shield layer 4 made of a seamless metal layer in close contact with the outer periphery of the insulator 3 is formed, and the differential transmission cable 1 according to the present embodiment is obtained.

  Note that the thickness of the conductive shield layer 4 can be controlled by appropriately selecting the size of the gap between the base 23 and the core metal 24, that is, the outer diameter of the base 23 and the inner diameter of the core metal 24.

  As described above, in the differential transmission cable 1 according to the present embodiment, the conductive shield layer 4 is formed of a seamless metal layer that is in close contact with the outer periphery of the insulator 3.

  Thereby, it is possible to suppress the generation of a gap between the insulator 3 and the conductive shield layer 4 and to suppress deterioration of characteristics such as skew. The conductive shield layer 4 made of a seamless metal layer in close contact with the outer periphery of the insulator 3 can be formed by metal sheath extrusion.

  In addition, when a metal tape is used for the conductive shield layer 4 as in the prior art, the metal tape is likely to wrinkle when bent, causing deterioration of the characteristics. However, the differential transmission cable 1 according to the present embodiment has According to this, since the conductive shield layer 4 is formed of a seamless metal layer that is in close contact with the outer periphery of the insulator 3, the generation of wrinkles during bending can be suppressed.

  Further, when a metal tape is used for the conductive shield layer 4 as in the prior art, there is a problem that it is difficult to weld the conductive shield layer 4, but in the differential transmission cable 1 according to the present embodiment, It can respond also to welding by adjusting the thickness of the conductive shield layer 4 appropriately.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

1 differential transmission cable 2 inner conductor 3 insulator 4 conductive shield layer

Claims (5)

At least two inner conductors;
An insulator provided to collectively cover the two inner conductors;
A conductive shield layer provided on the outer periphery of the insulator;
In the differential transmission cable with
The differential transmission cable, wherein the conductive shield layer is made of a seamless metal layer in close contact with the outer periphery of the insulator. At least two inner conductors;
An insulator provided to collectively cover the two inner conductors;
A conductive shield layer provided on the outer periphery of the insulator;
A method of manufacturing a differential transmission cable comprising:
A method for manufacturing a differential transmission cable, comprising providing a conductive shield layer made of a seamless metal layer in close contact with the outer periphery of the insulator by extruding a metal sheath on the outer periphery of the insulator. The metal sheath extruder is fed with the two inner conductors collectively covered with the insulator as a core wire, and a metal material is supplied as an extruded material, and the extruded material is extruded around the core wire, Form a metal pipe away from the core wire,
The method for manufacturing a differential transmission cable according to claim 2, wherein the conductive shield layer is formed by molding the metal pipe in accordance with an outer shape of the core wire with a molding die. The method for manufacturing a differential transmission cable according to claim 3, wherein the molding die is provided with cooling means for cooling the metal pipe. The manufacturing method of the differential transmission cable according to claim 4, wherein the cooling means includes a cooling water circulation path formed so as to pass through the inside of the molding die, and a cooling water circulation means for circulating cooling water through the cooling water circulation path. Method.

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