JP2006127853A - Coaxial cable and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve electric contacting property and flexibility of a coaxial cable. <P>SOLUTION: The coaxial cable 1 is composed of an internal conductor 3, an insulator 5 covering the outer periphery of the internal conductor 3, an external conductor 7 arranged on the outer periphery of the insulator 5, a metal plating layer 11 formed on the external conductor 7, and a sheath 13 covering the outer periphery of the metal plating layer 11. Electric contacting property is improved by applying the plating layer 11on the surface of the external conductor 7, further, the external conductor is annealed by the heating temperature at tin plating, by the above, the hardness of the external conductor 7 is reduced and the external conductor is softened, and the flexibility of the coaxial cable 1 is improved as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a coaxial cable used for transmission of various communication signals used in mobile communication base stations and electronic equipment, and a method for manufacturing the same, and more particularly to improve electrical contact and flexibility. The present invention relates to an improved coaxial cable and a method for manufacturing the same.

  Referring to FIGS. 10 and 11, conventionally, as the coaxial cable 101, an inner conductor 103 provided at the center of the cable, an insulator 105 concentrically coated on the outer periphery of the inner conductor 103, and the insulator 105 In general, an outer conductor 107 is provided concentrically on the outer periphery, and a sheath 109 as an outermost layer is coated on the outer side of the outer conductor 107.

  The outer conductor 107 is formed into a corrugated pipe having a corrugated shape in order to improve, for example, mechanical characteristics such as bending characteristics of the coaxial cable 101 (see, for example, Patent Document 1).

The inner conductor 103 is made of, for example, a silver-plated copper wire, an annealed copper wire, a tin-plated annealed copper wire, a tin-plated copper-coated steel wire, or the like. The insulator 105 includes, for example, foamed or solid polyethylene, crosslinked polyethylene, PTFE, PFA (including foam), FEP (including foam), and the like. For the sheath 109, for example, PVC or polyethylene is used.
JP 2003-123564 A

  By the way, in the conventional coaxial cable 101, when forming the outer conductor 107, for example, an oxygen-free copper tape is formed into a pipe shape (cylindrical shape), and then the butt portion is welded in the longitudinal direction. The welded copper pipe is corrugated to have its own flexibility. However, when the outer conductor 107 is formed, the welded copper pipe becomes hard due to work hardening, and the coaxial cable 101 itself becomes hard. That is, in the above process, the butt portion of the copper tape is (1) work hardening by mechanical bending (corrugation), and (2) thermal hardening by rapid heating and subsequent rapid cooling during welding, It was easy to receive. Depending on the manufacturing conditions, the processed copper pipe may have a Vickers hardness (Hv) of about twice.

  In addition, in order to solve the above-mentioned problems of work hardening and thermal hardening, even if an attempt is made to perform annealing (annealing or tempering) after forming the outer conductor 107, the oxidation of the outer conductor 107 proceeds, so this is a solution. It must not have been.

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

  The 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 metal plating layer coated on the outer peripheral surface of the outer conductor. It is characterized by comprising.

  The 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 metal plating layer coated on the outer peripheral surface of the outer conductor. And a sheath covering the outer periphery of the metal plating layer.

  In the coaxial cable according to the present invention, the outer conductor is preferably formed by covering the outer conductor in a tubular shape with a metal tape material and corrugating.

  The coaxial cable according to the present invention is preferably configured such that the outer conductor is covered with a metal tape material in a smooth tubular shape in the coaxial cable.

  In the coaxial cable according to the present invention, preferably, the outer conductor is made of copper, oxygen-free copper, or a copper alloy, and the metal plating layer is made of a tin plating layer.

  The method of manufacturing a coaxial cable according to the present invention includes a step of covering an outer periphery of an inner conductor with an insulator and providing an outer conductor on the outer periphery of the insulator, and a step of applying a metal plating layer to the outer peripheral surface of the outer conductor. , Characterized by having.

  The method of manufacturing a coaxial cable according to the present invention includes a step of covering an outer periphery of an inner conductor with an insulator and providing an outer conductor on the outer periphery of the insulator, and a step of applying a metal plating layer to the outer peripheral surface of the outer conductor. And a step of covering the outer periphery of the metal plating layer with a sheath.

  The method of manufacturing a coaxial cable according to the present invention includes a step of covering an outer periphery of an inner conductor with an insulator and providing an outer conductor coated with a metal plating layer on the outer periphery of the insulator, and an outer peripheral surface of the outer conductor. And a step of coating a sheath on the outer periphery of the coated metal plating layer.

  The method for manufacturing a coaxial cable according to the present invention is the method for manufacturing a coaxial cable, wherein the outer conductor is made of a metal tape material, and the metal tape material is coated on the outer periphery of the insulator in a tubular shape and then corrugated. It is preferable.

  In the method for manufacturing a coaxial cable according to the present invention, in the method for manufacturing a coaxial cable, the outer conductor is preferably made of a metal tape material, and the metal tape material is covered with a smooth tube around the outer periphery of the insulator.

  In the method for manufacturing a coaxial cable according to the present invention, in the method for manufacturing a coaxial cable, the outer conductor is preferably made of copper, oxygen-free copper, or a copper alloy, and the metal plating layer is preferably made of a tin plating layer.

  As understood from the means for solving the above problems, according to the coaxial cable of the present invention, a metal plating layer is applied to the surface of the outer conductor, and a sheath is applied to the surface of the metal plating layer. Therefore, the electrical contact property is improved. Furthermore, since the outer conductor is annealed (annealed or annealed) according to the heating temperature at the time of metal plating, the hardness of the outer conductor can be lowered and mechanically softened, and the flexibility can be improved.

  According to the manufacturing method of the coaxial cable of the present invention, for example, a metal plating layer can be easily provided on the surface of the outer conductor of the cable core by passing a metal plating tank storing molten metal plating, A sheath can be applied to the surface of the metal plating layer, and the electrical contact property of the coaxial cable can be improved by the metal plating layer. Moreover, since the outer conductor is annealed (annealed or annealed) at the heating temperature of the molten metal plating at the time of the above metal plating, the hardness of the outer conductor can be lowered to make it mechanically flexible. Can also be improved.

  Further, according to the manufacturing method of the coaxial cable of the present invention, the outer periphery of the insulator can be coated using an external conductor on which a metal plating layer has been applied in advance, and the electrical contact property of the coaxial cable can be improved by this metal plating layer. It can be improved.

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

  1 and 2, a coaxial cable 1 according to this embodiment includes an inner conductor 3, an insulator 5 covering the outer periphery of the inner conductor 3, and a metal tape material on the outer periphery of the insulator 5. A cable core 9 is composed of an outer conductor 7 that is covered with a welded seam tube and corrugated (corrugated), and a metal plating layer is applied to the surface of the outer conductor 7 of the cable core 9. For example, a tin plating layer 11 and a sheath 13 covering the outer periphery of the tin plating layer 11.

  In this embodiment, the inner conductor 3 is made of a silver-plated annealed copper wire having an outer diameter of 0.91 mm. The insulator 5 is made of, for example, PTFE as a fluororesin.

  Further, the outer conductor 7 is formed into a tubular shape (pipe shape) by a method such as welding of a butt of the copper tape while forming an oxygen-free copper tape, for example, as a metal tape material into a cylindrical shape vertically attached to the outer periphery of the insulator 5. ) And formed into a corrugated tube by corrugated spiral processing. Furthermore, the outer diameter of the outer conductor 7 is about 3.6 mm, the tape thickness is about 0.2 mm, the corrugation pitch is about 2 mm, and the corrugation depth is about 0.4 mm. Furthermore, the sheath 13 is polyethylene.

  For example, the tin plating layer 11 as the metal plating layer is shown in FIG. 6 which will be described later in detail, for example, as a tin plating apparatus in the same line or a separate line after the corrugating process of the outer conductor 7. The tin plating layer 11 is applied to the surface of the outer conductor 7 by passing through the molten tin plating tank 15 as shown in FIG. The tin plating layer 11 improves the electrical contact property of the coaxial cable 1 and further anneals (anneales or anneals) the outer conductor 7 at the heating temperature of the molten tin plating tank 15. Since it can be lowered and mechanically softened, the flexibility of the coaxial cable 1 can also be improved.

  The inner conductor 3 and the insulator 5 are made of the above materials in this embodiment. For example, the inner conductor 3 is made of various materials such as copper, tin-plated copper, and silver-plated copper-coated steel wire. The insulator 5 can be applied with PFA (including a foam structure) depending on conditions.

  Further, in this embodiment, the outer conductor 7 is formed into a corrugated pipe by corrugated spiral processing after being formed into a tubular shape using an oxygen-free copper tape as a metal tape material. However, it may be a smooth copper pipe as shown in FIG. The coaxial cable 1 shown in FIG. 3 is the same as the coaxial cable shown in FIG. 1 except that the outer conductor 7 is formed of a smooth copper pipe formed from a metal tape material in a tubular shape. .

  Further, the corrugation process may be spiral or independent. The material of the outer conductor 7 can be not only copper but also copper alloy.

  Further, the outer conductor 7 may be tubularly coated on the outer periphery of the insulator 5 using a metal tape material in which a metal plating layer has been previously applied. For example, the outer conductor 7 can be formed into a tubular shape using a copper tape whose surface is pre-plated with tin.

  Next, a method for manufacturing the coaxial cable 1 according to the embodiment of the present invention will be described. Note that members similar to those of the coaxial cable 1 of the above-described embodiment are described with the same reference numerals.

  The coaxial cable 1 is manufactured through manufacturing processes such as an insulating process, an outer conductor (corrugated) forming process, a tin plating process, and a sheath extrusion process. The cable core 9 constituting a part of the coaxial cable 1 is generally extruded by an insulating extrusion device (not shown) so as to cover the outer periphery of the inner conductor 3 with the outer conductor coating device. Thus, the outer conductor 7 is coated on the outer periphery of the insulator 5.

  For example, in the insulating process, the inner conductor 3 wound on the inner conductor feeding reel (not shown) is sent to a die of an insulating extruder (not shown). In this insulation extruder, for example, PTFE as a fluororesin as the insulator 5 is coated on the outer periphery of the inner conductor 3, and the insulation-coated inner conductor 17 shown in FIG.

  As shown in FIG. 4, the outer conductor (corrugated) forming step is performed by feeding the insulating coated inner conductor 17 formed in the above-described insulating step to the delivery reel 19, and The insulating covering inner conductor 17 is sent to the welding machine 21. On the other hand, a copper tape 7A as a metal tape material which is a raw material of the outer conductor 7 is wound on a copper tape feed reel 23, and the copper tape 7A is sent to the welding machine 21 through the outer conductor coating device 25.

  In the outer conductor coating apparatus 25, as shown in FIG. 5, the copper tape 7A is gradually wound around the outer periphery of the insulator 5 in a vertically attached state by a former (not shown) having a trumpet-shaped opening. The butt joint of the copper tape 7A is welded by the welding machine 21 to be formed into a welded seam tubular shape. Next, the outer conductor 7 of the weld seam is sandwiched between a pair of upper and lower caterpillars 29 of the take-up caterpillar 27 as shown in FIGS. 4 and 5 and sent out to the corrugator 31 provided on the downstream side.

  In the corrugator 31, the outer conductor 7 is corrugated (corrugated) by rotating the push rod 33 so as to press the outer periphery of the outer conductor 7 inward as shown in FIG. To be molded. In this embodiment, the corrugation process is formed in a spiral shape. Note that this corrugation processing may be in other forms such as an annular shape as described above, for example, a ring-shaped bent portion formed in the ring shape along the axial direction of the outer conductor 7 (annular shape). I do not care.

  Referring to FIG. 6, the cable core 9 is immersed in a molten tin plating 37 of, for example, a molten tin plating tank 15 as a tin plating apparatus, so that the surface of the outer conductor 7 is coated with the tin plating layer 11. . A fixed amount of molten tin plating 37 melted at 300 ° C. is always stored in the molten tin plating tank 15, and the cable core 9 passes through the molten tin plating tank 15 for a predetermined time set in advance. Sometimes, the molten tin plating 37 is uniformly coated on the outer surface of the outer conductor 7 of the cable core 9. A die 38 for making the molten tin plating 37 uniform may be provided at the outlet of the molten tin plating tank 15.

  Thereafter, the cable core 9 to which the tin plating layer 11 is applied passes through the die 39B of the extrusion head 39A of the sheath extrusion device 39, and the sheath 13 of, for example, polyethylene resin is formed on the corrugated tube 35 of the outer conductor 7 The coaxial cable 1 shown in FIGS. 1 and 2 is manufactured by extrusion molding so as to cover the outer periphery of the tin plating layer 11. The coaxial cable 1 passes through the cooling tank 41 and is cooled, and is then wound around the take-up reel 43. The plating coating and the sheath extrusion may be a series as shown in FIG. 6 or may be separate steps although not shown.

  Referring to FIG. 7, the inner conductor 3 is made of silver-plated annealed copper wire with an outer diameter of 0.91 mm, the insulator 5 is PTFE, the outer conductor 7 has an outer diameter of about 3.6 mm, and the tape thickness is about 0.2 mm. A cable core 9 having a diameter of 2 mm, a corrugation pitch of about 2 mm, and a corrugation depth of about 0.4 mm is immersed in a 300 ° C. molten tin plating tank 15 so that the tin plating layer 11 is uniformly formed on the outer conductor 7. The rate of change of the measurement result of the Vickers hardness (Hv) of the outer conductor 7 when coated is shown. In addition, the measured value of the Hv hardness in FIG. 7 is investigated at four points in the circumferential direction of the coaxial cable 1 and is an average value thereof.

  The graph of FIG. 8 shows that the Vickers hardness of the outer conductor 7 when the cable core 9 is immersed in a molten tin plating tank 15 at 350 ° C. and the tin plating layer 11 is uniformly applied on the outer conductor 7 ( The change rate of the measurement result of Hv) is shown. The measured value of the Hv hardness is an average value obtained by examining four points in the circumferential direction of the coaxial cable 1 as in FIG.

  From the above, as shown in the graphs of FIGS. 7 and 8, by increasing the immersion time of the cable core 9, the hardness of the outer conductor 7 is reduced. It can be seen that annealing (annealing or annealing) is effectively performed on the outer conductor 7 depending on the temperature.

  Referring to FIG. 9, since the hardness of the outer conductor 7 can be lowered and mechanically softened as described above, the flexibility of the coaxial cable 1 can also be improved. In this regard, the result of a cantilever deflection test of the coaxial cable 1 corresponding to the time of immersion in the 300 ° C. hot-dip tin plating tank 15 is shown. As conditions for the cantilever deflection test, the sample length of the coaxial cable 1 is 100 mm, and the load applied to the tip of the sample is 250 g.

  As can be seen from the graph of FIG. 9, since the rate of change in deflection (%) of the coaxial cable 1 increases as the immersion heating time in the molten tin plating tank 15 increases, the flexibility of the coaxial cable 1 is improved. is doing.

  From the above, by applying the tin plating layer 11 to the outer conductor 7, not only the flexibility of the coaxial cable 1 can be improved but also the contact resistance of the coaxial cable 1 can be reduced. As a result, when the outer conductor 7 of the coaxial cable 1 is connected to the connector, the (electrical) contact resistance of the dissimilar metal can be reduced (reduced), so that there is an effect of suppressing intermodulation distortion. Particularly, when the outer conductor 7 is corrugated (corrugated), the contact area with the connector tends to be small, so that tin plating, which is a metal material that can be easily soldered to the connector, is preferable.

It is a side view explaining the outline of the coaxial cable of embodiment of this invention. It is an expanded sectional view of the arrow II-II line of FIG.1 and FIG.3. It is a side view explaining the outline of the coaxial cable of other embodiment of this invention. It is a schematic explanatory drawing which shows the external conductor (corrugate) shaping | molding process among the manufacturing processes of the coaxial cable of embodiment of this invention. FIG. 5 is a perspective view schematically showing the process of FIG. 4. It is a schematic explanatory drawing which shows the tin plating process and the sheath extrusion process among the manufacturing processes of the coaxial cable of embodiment of this invention. It is a graph which shows the hardness change rate of an outer conductor at the time of being immersed in a 300 degreeC tin plating tank. It is a graph which shows the hardness change rate of an external conductor at the time of being immersed in a 350 degreeC tin plating tank. It is a graph which shows the deflection amount change rate of the coaxial cable corresponding to the time immersed in a 300 degreeC hot-dip tin plating tank. It is a side view explaining the outline of the conventional coaxial cable. It is an expanded sectional view of the arrow VI-VI line of FIG.

Explanation of symbols

1 Coaxial cable 3 Inner conductor 5 Insulator 7 Outer conductor 7A Copper tape (metal tape material)
9 Cable core 11 Tin plating layer (metal plating layer)
13 Sheath 15 Molten tin plating tank (tin plating equipment)
21 Welding Machine 25 Outer Conductor Coating Device 35 Corrugated Pipe 37 Hot Tin Plating 38 Dice

Claims (11)

  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 metal plating layer coated on the outer peripheral surface of the outer conductor, Coaxial cable.   An inner conductor, an insulator covering the outer periphery of the inner conductor, an outer conductor provided on the outer periphery of the insulator, a metal plating layer coated on the outer peripheral surface of the outer conductor, and an outer periphery of the metal plating layer A coaxial cable comprising a sheath coated with   The coaxial cable according to claim 1 or 2, wherein the outer conductor is formed by covering a tubular shape with a metal tape material and corrugating.   The coaxial cable according to claim 1 or 2, wherein the outer conductor is formed by covering a smooth tube with a metal tape material.   5. The coaxial cable according to claim 1, wherein the outer conductor is made of copper, oxygen-free copper, or a copper alloy, and the metal plating layer is made of a tin plating layer. Covering the outer periphery of the inner conductor with an insulator and providing an outer conductor on the outer periphery of the insulator;
Applying a metal plating layer to the outer peripheral surface of the outer conductor;
A method for manufacturing a coaxial cable, comprising: Covering the outer periphery of the inner conductor with an insulator and providing an outer conductor on the outer periphery of the insulator;
Applying a metal plating layer to the outer peripheral surface of the outer conductor;
Covering the outer periphery of the metal plating layer with a sheath;
A method for manufacturing a coaxial cable, comprising: Coating the outer periphery of the inner conductor with an insulator, and providing an outer conductor coated with a metal plating layer in advance on the outer periphery of the insulator;
Coating the sheath around the outer periphery of the metal plating layer coated on the outer peripheral surface of the outer conductor;
A method for manufacturing a coaxial cable, comprising:   The coaxial cable according to claim 6, 7 or 8, wherein the outer conductor is made of a metal tape material, and the metal tape material is coated on the outer periphery of the insulator in a tubular shape and then corrugated. Method.   9. The method for manufacturing a coaxial cable according to claim 6, wherein the outer conductor is made of a metal tape material, and the metal tape material is coated on the outer periphery of the insulator in a smooth tubular shape. The coaxial cable according to claim 6, 7, 8, 9 or 10, wherein the outer conductor is made of copper, oxygen-free copper, or a copper alloy, and the metal plating layer is made of a tin plating layer. Method.

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