JP6610817B1 - coaxial cable - Google Patents

Abstract

Provided is a coaxial cable that is not easily attenuated when a high-frequency signal is transmitted over a long distance and is easy to bend and route when a long distance is routed. SOLUTION: An inner conductor 2, an insulator 3 covering the periphery of the inner conductor 2, and a resin layer 411 and a metal layer 412 provided on one surface of the resin layer 411 are wound around the insulator 3. And the outer conductor 4 having the braided shield 42 covering the outer periphery of the tape member 41 and the sheath 5 covering the periphery of the outer conductor 4, and the inner conductor 2 twists a plurality of strands 2a. And a compression stranded conductor that has been compressed so that a cross-sectional shape perpendicular to the cable longitudinal direction has a predetermined shape, and at least a part of the tape member 41 is not in close contact with the insulator 3 and is a metal layer 412 is the outer side, and is wound around the insulator 3 vertically. [Selection] Figure 1

Description

  The present invention relates to a coaxial cable.

  In recent years, the market for human collaborative robots and small articulated robots is expanding as a measure to improve productivity. As a robot cable used for such a robot, a movable part cable wired to a movable part of the robot and a fixed part cable for connecting the robot and a control device are used.

  In addition, there exists patent document 1 as prior art document information relevant to invention of this application.

Japanese Patent No. 3671729

  For example, the fixed portion cable may transmit over a long distance of about 25 m to 100 m. In recent years, it has been required to transmit a high-frequency signal (for example, a band of 10 MHz to 6 GHz) such as a video signal taken by a camera installed in a robot or the like using a coaxial cable. Therefore, the coaxial cable used for the fixed portion cable is required to have high transmission characteristics capable of transmitting a high-frequency signal over a long distance.

  As such a coaxial cable, it can be considered that a tape member such as a copper tape provided with a copper foil on a resin layer is used as an external conductor. However, in such a coaxial cable, when a tape member such as a copper tape is spirally wound, a phenomenon called “suckout” in which abrupt attenuation occurs in a predetermined frequency band (for example, several GHz band) occurs. End up.

  In addition, as a coaxial cable used for the fixed portion cable, in the case where a tape member is vertically wound around the entire periphery of the insulator as shown in Patent Document 1 in close contact with the insulator. In this case, there is a restriction on the shape and location when the long distance from the robot to the control device is routed. For example, when a coaxial cable is bent and routed, there is a possibility that the high-frequency signal transmission characteristics may be deteriorated, for example, by pressing the insulator that is in close contact with the inner conductor or tape member that is difficult to bend. was there. For this reason, a coaxial cable that satisfies both high-frequency signal transmission characteristics (attenuation characteristics) and flexibility (flexibility) in long-distance transmission is desired.

  Therefore, an object of the present invention is to provide a coaxial cable that is not easily attenuated when a high-frequency signal is transmitted over a long distance and is easy to bend and route when a long distance is routed.

In order to solve the above problems, the present invention has an internal conductor, an insulator covering the periphery of the internal conductor, a resin layer, and a metal layer provided on one surface of the resin layer. An outer conductor having a tape member wound around an insulator and a braided shield covering an outer periphery of the tape member; and a sheath covering the outer conductor; and the inner conductor twists a plurality of strands. The tape member is formed of a compressed stranded conductor that is compressed so that a cross-sectional shape perpendicular to the cable longitudinal direction is a predetermined shape, and at least a part of the tape member enters a gap between the strands of the braided shield By having an inner air layer between the insulator and the inner air layer, the maximum distance from the surface of the insulator to the inner surface of the tape member is 5 μm or more and 30 μm or less in the inner air layer, A coaxial cable is provided that floats from the surface of the insulator to the braided shield side, and the tape member is vertically wound around the insulator with the metal layer as the outside.

  According to the present invention, it is possible to provide a coaxial cable that is not easily attenuated when a high-frequency signal is transmitted over a long distance and is easy to bend and route when extending a long distance.

It is a figure which shows the coaxial cable which concerns on one embodiment of this invention, (a) is sectional drawing which shows a cross section perpendicular | vertical to a cable longitudinal direction, (b) is the A section enlarged view. It is sectional drawing which shows a cross section perpendicular | vertical to the longitudinal direction of a tape member. It is explanatory drawing explaining a test of flexibility.

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

  1A and 1B are diagrams showing a coaxial cable according to the present embodiment, in which FIG. 1A is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the cable, and FIG.

  As shown in FIG. 1, the coaxial cable 1 includes an inner conductor 2, an insulator 3 that covers the periphery of the inner conductor 2, an outer conductor 4 that covers the periphery of the insulator 3, and a sheath 5 that covers the periphery of the outer conductor 4. And. The coaxial cable 1 is used, for example, as a cable for a fixed part that connects a robot and a control device in a factory or the like, and has a length of, for example, about 25 m to 100 m.

(Inner conductor 2)
In the coaxial cable 1 according to the present embodiment, the inner conductor 2 is compressed so that a plurality of strands 2a are twisted and the cross-sectional shape perpendicular to the cable longitudinal direction is a predetermined shape such as a circular shape. It consists of a compression stranded conductor. In the present embodiment, the inner conductor 2 is formed by compressing a stranded conductor in which seven strands 2a are concentrically twisted through a die having a smaller diameter and a circular outlet than the stranded conductor. did. The strand 2a arranged at the center has a substantially hexagonal shape in sectional view, and the six strands 2a arranged in the periphery have a substantially fan shape in sectional view. In the coaxial cable 1 according to the present embodiment shown in FIG. 1, an example in which the inner conductor 2 is configured by a compression stranded conductor having a circular cross-sectional shape is shown, but the cross-sectional shape is a shape other than a circular shape ( For example, the inner conductor 2 may be formed of a compressed twisted wire conductor that has been compressed into a polygonal shape such as a square shape. Since the inner conductor 2 is a compression stranded conductor having a circular cross-sectional shape, the coaxial cable 1 can be easily bent in any direction, and therefore, the inner conductor 2 is easily bent and routed.

  A normal stranded wire conductor is more flexible and easier to bend than a single wire conductor, but has a low electrical conductivity because there are many gaps between the strands. By using a compression stranded conductor as the inner conductor 2 as in the present embodiment, the strands 2a are in close contact with each other, and there is no gap between the strands 2a. Therefore, the conductivity is improved and good attenuation characteristics are obtained. As well as bendability. Moreover, since a compression twisted wire conductor is a twisted wire conductor, it is hard to be disconnected when bent compared with a single wire conductor.

  In order to obtain good attenuation characteristics, the electrical conductivity of the compression stranded conductor used as the inner conductor 2 is desirably 99% IACS or more. In the present embodiment, an annealed copper wire made of pure copper that has not been plated is used as the strand 2a of the inner conductor 2 in order to achieve high electrical conductivity. However, it may be applied as long as the plating has a conductivity of 99% IACS or higher. For example, an annealed copper wire subjected to silver plating may be used as the strand 2a. In addition, when the wire 2a is compressed through a die, distortion is imparted to the wire 2a and the electrical conductivity is lowered. Thereafter, the heat treatment (annealing treatment) is performed to remove the distortion and to conduct 99% IACS or more. Rate can be realized.

(Insulator 3)
The insulator 3 has a dielectric constant as low as possible in order to improve the transmission characteristics of high-frequency signals (more specifically, for example, it is difficult to attenuate when transmitting a high-frequency signal in a band of 10 MHz to 6 GHz for a long distance). It is desirable to use one. In the present embodiment, the insulator 3 is composed of a foamed layer 31 made of a foamed resin covering the periphery of the inner conductor 2 and a non-foamed layer 32 made of a non-foamed resin covering the periphery of the foamed layer 31. It was.

  As the foam layer 31, for example, a layer made of radiation cross-linked foamed polyethylene can be used. The foaming degree in the foaming layer 31 may be 40 to 70. When the foaming degree of the foaming layer 31 is less than 40, the dielectric constant increases and the high-frequency signal transmission characteristics deteriorate, and when the foaming degree exceeds 70, the foaming layer 31 becomes too soft and bent. This is because the external force generated in the coaxial cable 1 is easily crushed and the transmission characteristics of the high-frequency signal are deteriorated. As the non-foamed layer 32, a layer made of non-foamed radiation-crosslinked polyethylene formed by tube extrusion around the foamed layer 31 can be used. The non-foamed layer 32 plays the role of protecting the foamed layer 31 and maintaining the outer shape (cross-sectional shape) of the insulator 3 in a circular shape while having insulating properties. That is, by having the non-foamed layer 32, it is possible to prevent the foamed layer 31 from being crushed when the coaxial cable 1 is bent, etc., thereby suppressing the deterioration of the transmission characteristics of the high-frequency signal. Can do.

(Outer conductor 4)
The outer conductor 4 has a tape member 41 that is vertically attached around the insulator 3 and a braided shield 42 that covers the outer periphery of the tape member 41.

(Tape member 41)
FIG. 2 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the tape member 41. As shown in FIGS. 1 and 2, the tape member 41 includes a resin layer 411 and a metal layer (metal foil) 412 provided on one surface of the resin layer 411. The tape member 41 is formed, for example, by providing a metal layer 412 made of copper or aluminum on one surface of a resin layer 411 made of PET (polyethylene terephthalate).

  At least a part of the tape member 41 is not in close contact with a part of the insulator 3. The tape member 41 is vertically wound around the insulator 3 with the metal layer 412 on the outside. Further, the tape member 41 is not bonded and fixed to the outer periphery of the insulator 3. The tape member 41 is held by a braided shield 42 provided on the outer periphery thereof so as not to be unwound (so that the longitudinal auxiliary winding is not opened and the insulator 3 is not exposed).

  Here, “at least a part of the tape member 41 is not in close contact with the insulator 3” means that a part or all of the tape member 41 provided by vertical side winding around the insulator 3 is the insulator 3. It means not touching the surface. Specifically, as shown in FIG. 1B, a range in which the maximum distance d from the surface of the insulator 3 to the inner surface of the tape member 41 (the surface facing the surface of the insulator 3) is 5 μm or more and 30 μm or less. The state in which the tape member 41 floats from the surface of the insulator 3 to the braided shield 42 side. Note that the maximum distance d is an insulator when the coaxial cable 1 is cut at a predetermined position, and then the cross section of the cut portion (cross section perpendicular to the cable longitudinal direction) is observed using an optical microscope or an electron microscope. 3 is obtained by measuring the maximum value of the linear distance from the surface of 3 to the inner surface of the tape member 41.

  In the coaxial cable 1, since the tape member 41 is provided in a vertically attached winding around the insulator 3 in the state as described above, when the coaxial cable 1 is bent, the tape member 41 is attached to the surface of the insulator 3. Therefore, the stress on the insulator 3 caused by bending can be relieved and flexibility can be imparted to the coaxial cable 1. As a result, in the coaxial cable 1, the coaxial cable 1 is not stiff, and has good flexibility (for example, flexibility that is more flexible than the coaxial cable 1 in which the tape member 41 is spirally wound around the insulator 3). (Flexibility)). That is, the coaxial cable 1 has good high-frequency signal transmission characteristics in long-distance transmission, and is easy to route when it is bent and routed over long distances. In particular, when the distance d is 5 μm or more and 30 μm or less, the above-described functions and effects are easily obtained.

  Therefore, "at least a part of the tape member 41 is not in close contact with the insulator 3" means that one end of the tape member 41 in the circumferential direction overlaps the outer periphery of the other end. A portion that is not in close contact with the insulator 3 occurs in the vicinity of the end in the circumferential direction, or an air layer formed between the insulator 3 and the tape member 41 after bending the coaxial cable 1 or the like. It does not include that the tape member 41 is not in close contact with the insulator 3.

  From the viewpoint of facilitating bending of the coaxial cable 1, it is preferable to wind the tape member 41 in a spiral shape. However, in this case, a phenomenon called “suckout” in which abrupt attenuation occurs in a predetermined frequency band (for example, a band of several GHz) occurs. In the present embodiment, in order to suppress such a suck-out and improve the transmission characteristics of high-frequency signals in long-distance transmission, the tape member 41 is wound vertically.

  The thickness d1 of the resin layer 411 is preferably 9 μm or more and 16 μm or less. This is because if the thickness d1 is less than 9 μm, the tape member 41 is easily broken, and if it exceeds 16 μm, it becomes hard and the coaxial cable 1 is difficult to bend. The thickness d2 of the metal layer 412 is preferably 7 μm or more and 11 μm or less. This is because if the thickness d2 is less than 7 μm, the metal layer 412 is easily cracked when bent, and if it exceeds 11 μm, it becomes hard and the coaxial cable 1 becomes difficult to bend. In the present embodiment, the thickness d1 of the resin layer 411 is 12 μm, and the thickness d2 of the metal layer 412 is 9 μm.

  A part of the tape member 41 enters the gap 6 between the strands formed on the radially inner side of the braided shield 42 (see FIG. 1B). In addition, an inner air layer 7 is formed. For example, as shown in FIG. 1B, a gap 6 is formed between a plurality of first strands 421a constituting a first braided shield 421 of a braided shield 42 to be described later. The tape member 41 provided so as to be in contact with the first braided shield 421 is configured to enter. The inner air layer 7 is provided between the insulator 3 and the tape member 41 at the portion where the tape member 41 enters the gap 6. The tape member 41 is loosely wound around the insulator 3 (without being in close contact with the surface of the insulator 3) so that the inner air layer 7 is formed between the tape member 41 and the insulator 3.

  For example, when the tape member 41 is vertically wound around the insulator 3, the tape member 41 is loosely vertically wound so that a part of the inner surface of the tape member 41 does not contact the surface of the insulator 3, and then loosely vertically wound. The first braided shield 421 is provided around the tape member 41 so that the entire outer periphery of the tape member 41 is pressed (tightened) against the insulator 3 side by the first braided shield 421 of the braided shield 42. Thereby, a part of the tape member 41 is structured to enter the gap 6 between the first strands 421a constituting the first braided shield 421, and in the portion where the tape member 41 enters the gap 6, the insulator 3 and The inner air layer 7 can be formed between the tape member 41 and the tape member 41. With this configuration, the tape member 41 and the insulator 3 can move (slide) relative to the cable longitudinal direction or the cable circumferential direction when the coaxial cable 1 is bent at the time of routing. Therefore, the flexibility (flexibility) of the coaxial cable 1 is improved, and the coaxial cable 1 is easily bent. The tape member 41 and the first braided shield 421 are preferably formed continuously on the same production line.

  In order to improve the sliding between the tape member 41 and the insulator 3, the resin layer 411 of the tape member 41 may be made of a fluororesin. The resin layer 411 is located between the inner conductor 2 and the metal layer 412, and preferably has a dielectric constant as low as possible in order to contribute to transmission characteristics. An example of a fluororesin having a low dielectric constant and suitable for the resin layer 411 is PTFE (polytetrafluoroethylene). By using the tape member 41 having the resin layer 411 made of PTFE, it is possible to realize the coaxial cable 1 that is easier to bend and has better transmission characteristics of high-frequency signals.

  Further, for example, if the tape member 41 is tightly wound (closely adhered) by being bonded to the insulator 3, the tape member 41 is stretched and bent when the coaxial cable 1 is bent. There is a risk that the tape member 41 may be broken due to bending or bending. In this case, when the coaxial cable 1 is bent, the insulator 3 may be cracked, or the arrangement of the strands constituting the braided shield 42 may be disturbed and the strands may be disconnected. As in this embodiment, by loosely wrapping the tape member 41 around the insulator 3, the coaxial cable 1 can be more easily bent, and the tape member 41 can be prevented from being broken when the coaxial cable 1 is bent. Further, it is possible to prevent the insulator 3 from being cracked and the wires constituting the braided shield 42 from being broken.

  The tape member 41 has one end in the circumferential direction so that the insulator 3 is not exposed when the coaxial cable 1 is bent and the tape member 41 opens (unwinds vertically). It is preferable that the auxiliary winding is vertically attached so as to overlap the outer periphery of the other end. That is, the width w perpendicular to the longitudinal direction of the tape member 41 is preferably larger than the length of the outer periphery of the insulator 3. More specifically, the width w of the tape member 41 is desirably 1.3 times or more and less than 1.7 times the length of the outer periphery of the insulator 3. If the width w of the tape member 41 is less than 1.3 times the length of the outer periphery of the insulator 3, the tape member 41 may open and the insulator 3 may be exposed when the coaxial cable 1 is bent. This is because if the length of the outer periphery of the insulator 3 exceeds 1.7 times, the overlapping portion increases so that the coaxial cable 1 is hard and difficult to bend. Further, the width w of the tape member 41 is set to be 1.3 times or more and less than 1.7 times the outer peripheral length of the insulator 3, thereby forming a gap formed between the plurality of first strands 421 a. 6, the tape member 41 provided so as to be in contact with the first braided shield 421 can easily enter, and it is effective to provide the inner air layer 7 between the insulator 3 and the tape member 41.

(Braided shield 42)
The braided shield 42 is provided around the tape member 41, and is provided around the first braided shield 421 formed by weaving the first strands 421a and the first braided shield 421. The braided shield 42 is located outside the first strand 421a. A second braided shield 422 formed by weaving second strands 422a having a large diameter. For example, as described above, the braided shield 42 is provided with the first braided shield 421 by braiding a plurality of strands 421a around the tape member 42 loosely vertically wound around the insulator 3, and further, The first braided shield 421 can be formed by braiding a plurality of strands 422a and providing the second braided shield 422 in contact with the first braided shield 421. The formation of the first braided shield 421 and the second braided shield 422 may be performed continuously on the same production line or may be performed on separate production lines.

  The second braided shield 422 provided on the outside is mainly for shielding noise from the outside. The coaxial cable 1 is used in, for example, a factory, and is affected by large energy noise such as low-frequency noise caused by turning on and off a motor that drives a robot, a control device, and the like. For this reason, in the second braided shield 422, it is desirable to use the second strand 422a having a large outer diameter to reduce the conductor resistance.

  On the other hand, the first braided shield 421 provided on the inner side is mainly for suppressing internal signals from being radiated to the outside. Since the coaxial cable 1 transmits a high-frequency signal of 10 MHz to 6 GHz, for example, if the braided shield mesh (gap between the strands) is large, the signal is likely to be radiated to the outside. For this reason, in the first braided shield 421, it is desirable to use the first strands 421a having a small outer diameter to reduce the mesh. Moreover, if the outer diameter of the 1st strand 421a of the 1st braided shield 421 is enlarged, the coaxial cable 1 will become difficult to bend.

  More specifically, the outer diameter of the first strand 421a is preferably 0.08 mm or more and 0.14 mm or less in order to realize bendability and fineness of the mesh. Further, the outer diameter of the second strand 422a is preferably 0.10 mm or more and 0.16 mm or less in order to realize bendability and small conductor resistance. In order to clarify the functions of the first braided shield 421 and the second braided shield 422, the outer diameter of the first strand 421a may be 90% or less of the outer diameter of the second strand 422a. Here, the outer diameter of the first strand 421a is 0.12 mm, and the outer diameter of the second strand 422a is 0.14 mm.

(Sheath 5)
The sheath 5 is made of an insulating resin such as PVC (polyvinyl chloride), urethane, or polyolefin. The sheath 5 is formed by extrusion molding. However, if solid molding is performed, the resin constituting the sheath 5 enters between the strands 422a of the braided shield 42, and the coaxial cable 1 becomes hard and difficult to bend. Therefore, in the present embodiment, the sheath 5 is formed by tube extrusion. Accordingly, the resin constituting the sheath 5 is prevented from entering between the strands 422a of the braided shield 42, and the sheath 5 and the braided shield 42 are separated. That is, in the present embodiment, the sheath 5 and the braided shield 42 are not in close contact with each other, and the air layer 8 is formed between the strands 422a constituting the braided shield 42. With this configuration, the braided shield 42 can move relatively freely in the sheath 5 and the coaxial cable 1 can be easily bent.

(Characteristics of coaxial cable 1)
The coaxial cable 1 of Example 1 according to the present invention was manufactured by the manufacturing method described above, and the attenuation characteristics were measured. In the coaxial cable 1 of the first embodiment, the characteristic impedance is 75Ω, the distance d from the surface of the insulator 3 to the inner surface of the tape member 41 that is longitudinally wound is in the range of 5 μm to 30 μm, and the outer diameter is 7. It was set to 65 mm. For comparison, a coaxial cable of Comparative Example 1 having substantially the same configuration as that of Example 1 except that a normal stranded wire conductor was used as the inner conductor and the tape member was spirally wound was produced, and the attenuation characteristics were measured. . The measurement results of Example 1 and Comparative Example 1 are shown in Table 1.

  As shown in Table 1, the coaxial cable 1 of Example 1 has an attenuation characteristic in the 0.625 GHz band of 0.17 dB / m, an attenuation characteristic in the 1.25 GHz band of 0.28 dB / m, and a 6 GHz band. It can be seen that the attenuation characteristic is 0.82 dB / m, which is a very good attenuation characteristic. On the other hand, since the coaxial cable of Comparative Example 1 is also affected by sackout, the attenuation characteristic in the 0.625 GHz band is 0.49 dB / m, and the attenuation characteristic in the 1.25 GHz band is 1.41 dB / m. The attenuation characteristic in the m, 6 GHz band is 1.58 dB / m, which is a very large attenuation characteristic.

  Next, the coaxial cable 1 of Example 2 according to the present invention was produced in the same manner as the coaxial cable of Example 1, and tested for flexibility. In the coaxial cable 1 of Example 2, the distance d from the surface of the insulator 3 to the inner surface of the tape member 41 that is vertically wound is in the range of 5 μm to 30 μm. As shown in FIG. 3, in the flexibility test, the deflection of the coaxial cable 1 when one end of the coaxial cable 1 is fixed to the pedestal 91 and the other end is attached 1000 mm from the pedestal 91 and suspended by its own weight. The amount was measured. The amount of deflection was the distance from the base 91 to the coaxial cable 1 at a position 300 mm below the surface of the base 91. In consideration of the bending wrinkle applied to the coaxial cable 1, the amount of deflection was measured in the direction in which the bending wrinkle was applied (bending wrinkle direction) and in the opposite direction.

For comparison, Comparative Examples 2 and 3 in which the configuration of the inner conductor was changed and the tape member was vertically wound so as to be in close contact with the periphery of the insulator were prepared, and the same test was performed. In Comparative Example 2, the internal conductor 2 was a single wire conductor, and in Comparative Example 3, the internal conductor 2 was a stranded wire conductor. In both Example 2 and Comparative Examples 2 and 3, the conductor cross-sectional area was 0.82 mm ² and the characteristic impedance was 75Ω. Table 2 summarizes the results of the flexibility test.

  As shown in Table 2, in the coaxial cable 1 of Example 2 according to the present invention, it can be seen that the amount of deflection is as small as 150 mm or less in both the curl direction and the opposite direction, and good flexibility is obtained. On the other hand, in Comparative Example 2 in which the insulator and the tape member are in close contact with each other using a single wire conductor, the bending amount is 200 mm or more in both the bending heel direction and the opposite direction, and sufficient flexibility is obtained. It is not done. In Comparative Example 2, by using a stranded wire conductor, the amount of deflection is slightly smaller than that in Comparative Example 2, but due to the influence of the tape member 41 wound closely, the amount of deflection is 180 mm or more. It is getting bigger. Thus, the coaxial cable 1 according to the present invention realizes both good attenuation characteristics and good flexibility.

(Operation and effect of the embodiment)
As described above, in the coaxial cable 1 according to the present embodiment, the inner conductor 2 is formed by compressing the plurality of strands 2a so that the cross-sectional shape perpendicular to the cable longitudinal direction is a predetermined shape. The at least part of the tape member 41 is not in close contact with the insulator 3 but is wound around the insulator 3 with the metal layer 412 on the outside.

  The inner conductor 2 is composed of a compression stranded conductor, the tape member 41 is loosely wound around the insulator 3 (without being in close contact with the surface of the insulator 3), and the sheath 5 is formed by tube extrusion. Therefore, the transmission characteristic (attenuation characteristic) of the high-frequency signal of the coaxial cable 1 can be improved, and the flexibility of the coaxial cable 1 can be improved to facilitate bending. Can do. As a result, it is possible to realize the coaxial cable 1 that is not easily attenuated when a high-frequency signal is transmitted over a long distance and is easily bent and routed when the long distance is routed.

(Summary of embodiment)
Next, the technical idea grasped from the embodiment described above will be described with reference to the reference numerals in the embodiment. However, the reference numerals and the like in the following description are not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1] An inner conductor (2), an insulator (3) covering the periphery of the inner conductor (2), a metal layer (411) and a metal layer (1) provided on one surface of the resin layer (411) 412) and the outer conductor (4) having a tape member (41) wound around the insulator (3) and a braided shield (42) covering the outer periphery of the tape member (41), A sheath (5) covering the periphery of the conductor (4), and the inner conductor (2) is formed by twisting a plurality of strands (2a) and having a predetermined cross-sectional shape perpendicular to the cable longitudinal direction. It is composed of a compression twisted wire conductor that has been compressed so that at least a part of the tape member (41) is not in close contact with the insulator (3), and the metal layer (412) is the outside. Coaxial cable that is vertically wound around the insulator (3) (1).

[2] In the outer conductor (4), the braided shield (42) is not in close contact with the sheath (5), and an air layer is formed between the strands (422a) constituting the braided shield (42). (8) The coaxial cable (1) according to [1].

[3] The tape member (41) is vertically wound around the insulator (3) so that an inner air layer (7) is formed between the tape member (41) and the insulator (3). The coaxial cable (1) according to [1] or [2].

[4] Part of the tape member (41) enters the gap (6) between the strands (421a) of the braided shield (42), thereby forming the air layer (7). [3] The coaxial cable according to [3].

[5] The tape member (41) according to any one of [1] to [4], wherein the tape member (41) is wound so that one end in the circumferential direction overlaps the outer periphery of the other end. Coaxial cable (1).

[6] The braided shield (42) is provided around the tape member (41), and includes a first braided shield (421) formed by weaving first strands (421a), and the first braided shield ( 421) and a second braided shield (422) formed by weaving a second strand (422a) having a diameter larger than that of the first strand (421a), [1] to [1] 5] The coaxial cable (1) according to any one of the above.

[7] The coaxial cable (1) according to any one of [1] to [6], wherein the resin layer (411) of the tape member (41) is made of a fluororesin.

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Coaxial cable 2 ... Internal conductor 2a ... Wire 3 ... Insulator 4 ... External conductor 41 ... Tape member 411 ... Resin layer 412 ... Metal layer 42 ... Braided shield 421 ... 1st braided shield 421a ... 1st strand 422 ... Second braided shield 422a ... second strand 5 ... sheath 7 ... inner air layer 8 ... air layer

Claims (5)

An inner conductor,
An insulator covering the periphery of the inner conductor;
An outer conductor having a resin layer and a metal layer provided on one surface of the resin layer and having a braided shield covering a tape member wound around the insulator and an outer periphery of the tape member;
A sheath covering the periphery of the outer conductor,
The inner conductor is composed of a compressed twisted wire conductor that is formed by twisting a plurality of strands and being compressed so that a cross-sectional shape perpendicular to the cable longitudinal direction is a predetermined shape,
At least a part of the tape member has an inner air layer with the insulator by entering a gap between the strands of the braided shield. In the inner air layer, the tape extends from the surface of the insulator. In the range where the maximum distance to the inner surface of the member is 5 μm or more and 30 μm or less, it floats from the surface of the insulator to the braided shield side ,
The tape member is vertically wound around the insulator with the metal layer as the outside,
coaxial cable. The outer conductor, the braided shield is not in close contact with the sheath, and has an air layer between the strands constituting the braided shield,
The coaxial cable according to claim 1. The tape member is wound so that one end in the circumferential direction overlaps the outer periphery of the other end,
The coaxial cable according to claim 1 or 2 . The braided shield is provided around the tape member, and is provided around the first braided shield and the first braided shield, and has a diameter larger than that of the first strand. A second braided shield formed by weaving the second strands,
The coaxial cable according to any one of claims 1 to 3 . The resin layer of the tape member is made of a fluororesin,
The coaxial cable according to any one of claims 1 to 4 .

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