JP2023045115A - Coaxial cable and multicore cable - Google Patents

Abstract

To provide a coaxial cable that barely causes sudden attenuation in a predetermined frequency band and has a reduced loss.SOLUTION: A coaxial cable 1 comprises a conductor 2, an insulator 3 that covers the outer face of the conductor 2, a shield layer 4 that covers the outer face of the insulator 3, and a sheath 5 that covers the outer face of the shield layer 4. The shield layer 4 comprises a spiral shield part 41 in which metal strands 411 being elliptical in a cross section perpendicular to a longitudinal direction are spirally wound around the insulator 3, and a collective plating part 42 that covers the outer face of the spiral shield part 41 and is composed of conductive plating.SELECTED DRAWING: Figure 1

Description

The present invention relates to coaxial cables and multicore cables.

Coaxial cables are used as high-frequency signal transmission cables for internal wiring of electronic devices such as imaging devices used for autonomous driving, smartphones, tablet terminals, etc., or as wiring for machine tools such as industrial robots. .

As a conventional coaxial cable, a tape member such as a copper tape having a copper foil on a resin layer is spirally wound around an insulator to form a shield layer (for example, Patent Document 1). reference).

JP-A-2000-285747

However, in the conventional coaxial cable described above, wrinkles in the tape member and gaps around the shield layer due to the wrinkles in the tape member cause radiation loss and multiple reflections. There is a problem that the loss in the region becomes large. In addition, the above-described conventional coaxial cable has a problem that a phenomenon called suck-out occurs in which rapid attenuation occurs in a predetermined frequency band (for example, a band of several GHz such as 1.25 GHz).

On the other hand, in order to eliminate the above-described gap around the shield layer, for example, it is conceivable to form a hot-dip tin-plated layer on the outer layer of the braided shield. However, in this case, although the radiation loss can be reduced, the skin effect causes the signal current to concentrate on the protruding portion of the wires forming the braided shield. As a result, the cross-sectional area of the portion through which the current passes becomes small, increasing the conductor loss of the cable.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a coaxial cable in which abrupt attenuation is unlikely to occur in a predetermined frequency band and loss is reduced.

In order to solve the above problems, the present invention includes a conductor, an insulator that surrounds the conductor, a shield layer that surrounds the insulator, and a sheath that surrounds the shield layer. , the shield layer includes a horizontally wound shield portion configured by spirally winding a plurality of metal wires having an elliptical cross section perpendicular to the longitudinal direction around the insulator, and the horizontally wound shield portion. A coaxial cable having a bulk plating portion of conductive plating surrounding the periphery.

Further, in order to solve the above-mentioned problems, the present invention provides a conductor, an insulator covering the circumference of the conductor, a shield layer covering the circumference of the insulator, a sheath covering the circumference of the shield layer, and the shield layer includes a horizontally wound shield portion configured by spirally winding a plurality of metal wires around the insulator, and a batch plating portion made of hot-dip plating covering the periphery of the horizontally wound shield portion. and, the plurality of metal wires are rectangular metal wires having a rectangular cross-sectional shape perpendicular to the longitudinal direction of the metal wires and an arc-shaped outer edge along the cable circumferential direction Provide a coaxial cable.

Further, in order to solve the above problems, the present invention provides a multicore cable including at least one coaxial cable.

According to the present invention, it is possible to provide a coaxial cable in which abrupt attenuation is unlikely to occur in a predetermined frequency band and loss is reduced.

BRIEF DESCRIPTION OF THE DRAWINGS 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 an A section enlarged view of (a). FIG. 4 is a cross-sectional view showing a terminal portion of a cable assembly according to one embodiment of the present invention; FIG. 5 is a cross-sectional view showing a cross section perpendicular to the cable longitudinal direction of a coaxial cable according to another embodiment of the present invention; 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a multicore cable according to one embodiment of the present invention; FIG.

[Embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

1A and 1B are views showing a coaxial cable according to the present embodiment, FIG. 1A being a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the cable, and FIG. The coaxial cable 1 is used, for example, as an imaging device used for automatic driving or the like, internal wiring of electronic devices such as smartphones and tablet terminals, or wiring in machine tools such as industrial robots.

As shown in FIGS. 1(a) and 1(b), a coaxial cable 1 includes a conductor 2, an insulator 3 provided so as to cover the conductor 2, and an insulator 3 provided so as to cover the periphery of the insulator 3. and a sheath 5 provided so as to cover the periphery of the shield layer 4. - 特許庁

The conductor 2 is composed of a twisted wire conductor in which a plurality of metal wires are twisted together. In this embodiment, an annealed copper wire having an outer diameter of 0.285 mm is used as the metal wire, and the conductor 2 is formed by twisting seven metal wires. However, the number and outer diameter of the metal wires are not limited to this. In addition, from the viewpoint of improving electrical conductivity and mechanical strength, the metal wires include tin (Sn), silver (Ag), indium (In), titanium (Ti), magnesium (Mg), iron (Fe), and the like. A copper alloy wire containing may be used. Moreover, the metal wire used for the conductor 2 may be an aluminum wire or an aluminum alloy wire.

Alternatively, the conductor 2 may be a compressed stranded wire conductor obtained by twisting metal wires and then compressing the wire so that the cross-sectional shape perpendicular to the longitudinal direction of the cable is circular. By using a compressed twisted wire conductor as the conductor 2, the electrical conductivity is improved, good transmission characteristics are obtained, and flexibility can be maintained.

The insulator 3 is made of, for example, a fluororesin such as PFA (perfluoroalkoxyalkane) or FEP (tetrafluoroethylene/hexafluoropropylene copolymer), polyethylene, polypropylene, or the like. In this embodiment, the insulator 3 made of FEP with an outer diameter of 0.98 mm is used. The insulator 3 may be a foamed resin, or may be made of a crosslinked resin to improve heat resistance. Moreover, the insulator 3 may further have a multilayer structure. For example, a first non-foamed layer made of non-foamed polyethylene is provided around the conductor 2, a foamed layer made of foamed polyethylene is provided around the first non-foamed layer, and a second non-foamed layer made of non-foamed polyethylene is provided around the foamed layer. A three-layer structure having two non-foamed layers can also be used. In this embodiment, the insulator 3 made of PFA is formed around the conductor 2 by tube extrusion. By forming the insulator 3 by tube extrusion, the insulator 3 can be easily peeled off from the conductor 2 at the time of terminal processing, and the terminal processability is improved.

The sheath 5 is made of, for example, a fluororesin such as PFA or FEP, polyvinyl chloride, crosslinked polyolefin, or the like. In this embodiment, the sheath 5 made of fluororesin and having a thickness of 0.1 mm is formed by tube extrusion.

(Shield layer 4)
In the coaxial cable 1 according to the present embodiment, the shield layer 4 includes the horizontally wound shield portion 41 in which a plurality of metal wires 411 are spirally wound around the insulator 3, and the entire circumference of the horizontally wound shield portion 41. and a conductive collective plating portion 42 provided so as to collectively cover.

In the present embodiment, since the metal wires 411 are fixed by the collectively plated portion 42, in order to secure the bendability of the coaxial cable 1, the metal wires 411 should have a low yield strength that is likely to be plastically deformed. material must be used. More specifically, the metal wire 411 preferably has a tensile strength of 200 MPa or more and 380 Pa or less and an elongation of 7% or more and 20% or less.

In the present embodiment, as the metal wire 411, a silver-plated annealed copper wire having a plating layer 411b made of silver around a metal wire 411a made of an annealed copper wire is used. The metal wire 411a is not limited to the annealed copper wire, and may be a copper alloy wire, an aluminum wire, an aluminum alloy wire, or a wire having a low softening temperature obtained by adding a small amount of metal element (for example, titanium, magnesium, etc.) to pure copper. can be used. Moreover, the metal forming the plated layer 411b is not limited to silver, and may be tin or gold, for example. It is also possible to omit the plating layer 411b.

In the coaxial cable 1 according to the present embodiment, the metal wire 411 forming the horizontally wound shield portion 41 of the shield layer 4 has a shape (cross-sectional shape) in a cross section perpendicular to the longitudinal direction of the metal wire 411 from an ellipse to It is composed of elliptical metal wires. In particular, the metal wire 411 composed of an elliptical metal wire has a shape in a cross section perpendicular to the longitudinal direction of the metal wire 411.
It is preferable that the elliptical shape satisfies 35% or more and 50% or less of the ellipticity obtained in . For example, even if a metal wire having a circular cross section is used, the metal wire may be spirally wound so that the cross section perpendicular to the longitudinal direction of the cable may have an elliptical shape. However, in the present embodiment, the cross-sectional shape is not an elliptical shape because the cut surface is inclined with respect to the longitudinal direction of the metal wire 411, but the cross-sectional shape of the metal wire 411 itself. (Cross-sectional shape perpendicular to the longitudinal direction of the metal wire 411) is an elliptical shape. The major axis and minor axis used for the ellipticity expressed by the above formula are obtained not from the cross section perpendicular to the longitudinal direction of the cable but from the cross section perpendicular to the longitudinal direction of the metal wire 411 . The cross-sectional shape of the metal wire 411 can be controlled by the shape of the die used for wire drawing.

By using an elliptical metal wire as the metal wire 411, the metal wire 411 is arranged in close contact with (proximity to) the insulator 3 side as compared with the case of using a metal wire having a circular cross section. Also, a gap is less likely to occur between the shield portion 41 and the batch plating portion 42 . Therefore, even when the cable 1 is bent and wired, rapid attenuation is unlikely to occur in a predetermined frequency band, and transmission with reduced loss is possible. In particular, by using an elliptical metal wire having an ellipticity of 35% or more and 50% or less as the metal wire 411, the metal wire 411 is in closer contact with the insulator 3 than when a metal wire having a circular cross section is used. It is possible to arrange the metal wires 411 close to each other (adjacent), widen the cross-sectional area through which the current passes (current-passing cross-sectional area), and reduce the conductor loss in the shield layer 4. .

As the collectively plated portion 42 made of hot-dip plating, one made of tin was used. However, the material is not limited to this, and the collectively plated portion 42 may be made of, for example, silver, gold, copper, zinc, or the like. However, from the viewpoint of ease of manufacture, it is more preferable to use the batch plating portion 42 made of tin.

When forming the collectively plated portion 42, first, a plurality of metal wires 411 are twisted around the insulator 3 to form the laterally wound shield portion 41, and then the wire is passed through a plating bath in which molten tin is stored. A batch plating portion 42 is formed by cooling. That is, the batch plated portion 42 is a hot-dip plated layer formed by hot-dip plating.

Plating in which tin is retained at a temperature of 250° C. or more and less than 300° C. after applying flux to the periphery of the horizontally wound shield portion 41 so that tin can easily adhere to the entire periphery of the horizontally wound shield portion 41 . It is desirable to pass it through a tank. The linear velocity when passing through the plating bath is, for example, 40 m/min or more and 80 m/min or less, more preferably 50 m/min or more and 70 m/min or less. The flux is intended to make it easier for the molten tin to adhere to the entire periphery of the laterally wound shield portion 41, and contains chlorine and zinc as its main components. As the flux, for example, a rosin-based flux or the like can be used. The wire that has passed through the plating layer is preferably passed through a die to remove unnecessary tin. At this time, by adjusting the hole diameter of the die, the amount of tin adhered, that is, the thickness of the batch plating portion 42 can be adjusted.

When forming the batch plating portion 42, the silver forming the plating layer 411b in the portion that contacts the molten tin (that is, hot-dip plating) diffuses into the tin in the plating tank, and the metal wire 411 and the batch plating portion 42 are separated. An intermetallic compound 411c containing copper and tin is formed between (that is, between the metal wire 411a and the batch plating portion 42 and in contact with the surface of the metal wire 411a). When the present inventors performed EDX analysis (analysis by energy dispersive X-ray spectroscopy) using a SEM (scanning electron microscope), the surface of the metal wire 411 (metal wire 411 and collectively plated portion 42) It was confirmed that an intermetallic compound 411c composed of copper and tin was present in a layered manner between . That is, the intermetallic compound 411c is formed by a metallic diffusion reaction between the metal element (such as tin) forming the batch plating portion 42 formed by hot-dip plating and the metal element (such as copper) forming the main component of the metal wire 411. A compound layer is formed on the surface of the metal wire 411 . The thickness of the layer of the intermetallic compound 411c is, for example, about 0.2 μm to 1.5 μm. Although the intermetallic compound 411c is considered to contain silver constituting the plating layer 411b, the amount of silver in the intermetallic compound 411c is so small that it is difficult to detect by EDX analysis.

The intermetallic compound 411c is formed between the metal wires 411 and the batch-plated portion 42, so that when the coaxial cable 1 is repeatedly bent or twisted, the surface of the metal wires 411 is The batch-plated portion 42 is less likely to peel off from the metal wire 411 and the batch-plated portion 42 is less likely to form a gap. As a result, even when the coaxial cable 1 is bent or twisted, the laterally wound shield portion 41 can be kept fixed by the batch plating portion 42 from the outside of the laterally wound shield portion 41, and the shield layer 4 and the shield layer 4 can be fixed. The distance to the conductor 2 becomes difficult to change. Therefore, in the coaxial cable 1, the shielding effect is less likely to deteriorate due to bending or twisting, and rapid attenuation in a predetermined frequency band is less likely to occur. The thickness of the layer of the intermetallic compound 411c can be obtained by observing a cross section of the coaxial cable 1 (a cross section perpendicular to the longitudinal direction of the coaxial cable 1) using an optical microscope or an electron microscope, for example.

A plated layer 411b made of silver remains on the portion of the metal wire 411 that does not come into contact with the batch plating portion 42 (the portion of the metal wire 411 that does not come into contact with tin melted during plating). That is, the plated layer 411b made of silver remains on the metal wire 411 at the inner side (on the insulator 3 side) in the radial direction of the cable. That is, the shield layer 4 in the coaxial cable 1 according to the present embodiment has the plurality of metal wires 411 covered with the collectively plated portion 42 rather than the outer peripheral portion 4a where the plurality of metal wires 411 are covered with the collectively plated portion 42. The electrical conductivity of the inner peripheral portion 4b where the plated layer 411b is exposed is high. In the transmission of high-frequency signals, the current concentrates on the insulator 3 side of the shield layer 4. Therefore, the presence of the plated layer 411b having high electrical conductivity such as silver on the inner peripheral portion 4b of the shield layer 4 allows the shield layer It is possible to suppress the decrease in the conductivity of 4 and maintain good attenuation characteristics. The electrical conductivity of the tin plating forming the batch plating portion 42 is 15% IACS, and the electrical conductivity of the silver plating forming the plating layer 411b is 108% IACS.

The outer peripheral portion 4a referred to here is a portion (that is, a portion where the intermetallic compound 411c is formed) where the metal wire 411 is in contact with molten plating (such as tin) during hot-dip plating. The inner peripheral portion 4b is a portion where the plated layer 411b made of silver plating or the like remains.

The shield layer 4 has a spaced portion 45 where circumferentially adjacent metal wires are spaced apart from each other. Note that it is not necessary for all the metal wires 411 to be spaced apart, and there may be a contact portion where some of the metal wires 411 that are adjacent in the circumferential direction are in contact with each other. At the contact portion, the outer circumference of the horizontally wound shield portion 41 has a filling portion filled with the collectively plated portion 42 between the metal wires 411 adjacent in the circumferential direction.

The shield layer 4 has a connecting portion 43 in which the metal wires 411 adjacent in the circumferential direction are connected by the collectively plated portion 42 at the spaced portion 45 . It is desirable that the collectively plated portion 42 be provided so as to collectively cover the entire periphery of the laterally wound shield portion 41 in the circumferential direction and the axial direction, and mechanically and electrically connect the plurality of metal wires 411 . In the shield layer 4 of the coaxial cable 1 according to the present embodiment, connecting portions 43 are provided between adjacent inner peripheral portions 4b. Since the periphery of the inner peripheral portion 4b is not covered with the collectively plated portion 42, there is no contact between the inner peripheral portions 4b of the adjacent metal wires 411 and between the outer surface of the insulator 3 and the collectively plated portion 42 (connecting portion 43). ), there is an air layer 44 between them.

Regarding this air layer 44 , the inner surface of the connecting portion 43 facing the outer surface of the insulator 3 has a curved shape that is recessed toward the inner side of the connecting portion 43 (outside in the cable radial direction). That is, in the spaced portion 45, the inner surface of the connecting portion 43 has a recessed shape that is recessed outward in the cable radial direction. By having such a curved shape, an air layer 44 of a predetermined size can be provided between the outer surface of the insulator 3 and the inner surface of the connecting portion 43, so that the shielding effect is less likely to decrease, and the predetermined (for example, a frequency band up to 26 GHz), the coaxial cable 1 is less prone to abrupt attenuation. In addition, since the inner surface of the connecting portion 43 has a curved shape, the collectively plated portion 42 is less likely to crack or peel off.

Furthermore, by having the air layer 44 between the adjacent metal wires 411, compared to the case where all the metal wires 411 adjacent in the circumferential direction are in contact with each other, the collective plating portion is not affected when bending or twisting is applied. 42 is less likely to crack or peel off. In order to further suppress cracking and peeling of the collectively plated portion 42 , the collectively plated portion 42 is preferably made of a material that is more flexible than the metal wire 411 . As a result, when the coaxial cable 1 is bent or twisted, the collectively plated portion 42 between the metal wires 411 is stretched, and the flexibility of the shield layer 4 as a whole is improved. The distance between the metal wires 411 adjacent in the circumferential direction (the distance along the cable circumferential direction) is preferably half or less of the outer diameter (maximum outer diameter, here the major diameter) of the metal wires 411 . Thereby, the conductor loss of the shield layer 4 can be suppressed.

Moreover, it is preferable that the space occupation ratio of the collectively plated portion 42 is 50% or less with respect to the gap between the metal wires 411 . Here, the gap between the metal wires 411 means a circumscribed circle of the horizontally wound shield part 41 (a circle having a minimum diameter centered on the center of the cable and containing all the metal wires 411 of the horizontally wound shield part 41). It is a space between the outer surface of the insulator 3 and a space in which the metal wire 411 does not exist. In other words, the space occupation ratio of the air layer 44 in the gap between the metal wires 411 is preferably larger than 50%, and the space occupation ratio of the air layer 44 in the gap is equal to the space occupation ratio of the batch plating portion 42. should be larger than

More preferably, the collectively plated portion 42 is formed only outside the center of each of the plurality of metal wires 411 constituting the laterally wound shield portion 41 in the cable radial direction in a cross section perpendicular to the longitudinal direction of the cable. . As a result, dielectric loss and conductor loss caused by the collective plating portion 42 can be suppressed. A dashed-dotted line indicated by reference numeral 46 in FIG. 1 indicates an imaginary line connecting the centers of the metal wires 411 .

For example, if the shield layer 4 is composed of only the horizontally wound shield portion 41, gaps are generated between the metal wires 411, resulting in deterioration of noise characteristics. Furthermore, due to the effect of gaps between the metal wires 411, a phenomenon called suck-out occurs in which rapid attenuation occurs in a predetermined frequency band (for example, a band of 10 GHz to 25 GHz). As in the present embodiment, by providing the collectively plated portion 42 made of hot-dip plating so as to cover the entire periphery of the horizontally wound shield portion 41, the collectively plated portion 42 can block the gaps between the metal wires 411. , can improve the shield effect. As a result, signal transmission loss is less likely to occur. Furthermore, since the gap between the metal wires 411 is eliminated, it is possible to suppress the occurrence of suck-out.

Furthermore, by providing the collectively plated portion 42 so as to cover the circumference of the horizontally wound shield portion 41, the metal wire 411 is unwound when the shield layer 4 is exposed by removing the sheath 5 at the cable terminal portion during terminal processing. It becomes difficult, and it becomes possible to perform terminal processing easily. Furthermore, by providing the collectively plated portion 42 so as to cover the circumference of the horizontally wound shield portion 41, it is possible to stably maintain the impedance constant in the longitudinal direction of the cable.

(cable assembly)
Next, a cable assembly using the coaxial cable 1 will be described. FIG. 2 is a cross-sectional view showing the terminal portion of the cable assembly according to this embodiment.

As shown in FIG. 2 , cable assembly 10 includes coaxial cable 1 according to the present embodiment and terminal member 11 integrally provided at least one end of coaxial cable 1 .

The terminal member 11 is, for example, a connector, a sensor, a board mounted in a connector or sensor, or a board in an electronic device. FIG. 2 shows a case where the terminal member 11 is the substrate 11a. A signal electrode 12 to which the conductor 2 is connected and a ground electrode 13 to which the shield layer 4 is connected are formed on the substrate 11a. The substrate 11a is a printed circuit board in which a conductor pattern including the signal electrodes 12 and the ground electrodes 13 is printed on a base material 16 made of resin.

At the end of the coaxial cable 1, the sheath 5 of a predetermined length is removed from the end to expose the shield layer 4, and the exposed shield layer 4 and the end of the insulator 3 are removed to form the conductor 2. is exposed. The exposed conductor 2 is fixed to the signal electrode 12 by a connecting material 14 such as solder, and the conductor 2 is electrically connected to the signal electrode 12 . Also, the exposed shield layer 4 is fixed to the ground electrode 13 by a connection material 15 such as solder, and the shield layer 4 is electrically connected to the ground electrode 13 . The conductor 2 and the shield layer 4 may be connected without using the connection materials 14 and 15 such as solder. or shield layer 4 may be connected. Moreover, when the terminal member 11 is a connector or a sensor, the conductor 2 or the shield layer 4 may be directly connected to the electrode or element.

(Actions and effects of the embodiment)
As described above, in the coaxial cable 1 according to the present embodiment, the shield layer 4 includes a plurality of metal wires 411 having an elliptical cross-sectional shape perpendicular to the longitudinal direction, which are spirally wound around the insulator 3 . It has a horizontally wound shield portion 41 configured by winding and a batch plated portion 42 made of hot-dip plating that covers the periphery of the horizontally wound shield portion 41 . Further, in the coaxial cable 1 according to the present embodiment, the cross-sectional shape of the metal wires 411 perpendicular to the longitudinal direction of the metal wires 411 constituting the horizontally wound shield portion 41 of the shield layer 4 has an ellipticity of 35. % or more and 50% or less of elliptical metal wire is used.

By configuring in this way, the shield layer 4 is connected substantially all around via the collectively plated portion 42, and the gaps between the metal wires 411 of the laterally wound shielding portion 41 can be closed by the collectively plated portion 42. It becomes possible to improve noise characteristics and suppress the occurrence of suck-out. That is, according to the present embodiment, it is possible to realize the coaxial cable 1 in which the shielding effect is less likely to deteriorate and in which rapid attenuation is less likely to occur in a predetermined frequency band (for example, a frequency band up to 26 GHz).

Furthermore, by using an elliptical metal wire 411 as the metal wire 411 constituting the horizontally wound shield part 41, the metal wire 411 is brought into closer contact with the insulator 3 to widen the cross-sectional area through which the current passes, thereby reducing the conductor loss. can be reduced. That is, according to the present embodiment, it is possible to realize the coaxial cable 1 in which abrupt attenuation is unlikely to occur in a predetermined frequency band and loss is reduced.

(Other embodiments)
In the above-described embodiment, the case of using an elliptical metal wire as the metal wire 411 constituting the horizontally wound shield part 41 has been described. A rectangular metal wire having a rectangular cross-sectional shape perpendicular to the longitudinal direction of the metal wire 411 and having an arcuate (arch-shaped) outer edge along the cable circumferential direction may be used. Of the outer edge of the rectangular metal wire, the surface facing the insulator 3 is preferably arcuate having the same curvature as the outer peripheral surface of the insulator 3 . Since the metal wire 411 made of a rectangular metal wire has such a shape, as shown in FIG. 3 is arranged in surface contact with the outer peripheral surface of . Even in this case, the same effects as those of the above-described embodiment can be obtained. It should be noted that the cross-sectional shape of the metal wire 411 does not have to be strictly elliptical or rectangular, and some deformation is allowed. For example, the cross-sectional shape of the metal wire 411 may be an elliptical and arcuate shape, that is, an elliptical shape whose major axis is curved in an arc along the cable circumferential direction.

Further, in the above-described embodiment, the batch-plated portion 42 is formed by hot-dip plating, but the batch-plated portion 42 may be formed by coating with conductive resin.

Furthermore, a multicore cable including at least one coaxial cable 1 described above may be used. For example, like a multi-core cable 100 shown in FIG. 102 is wound around the tape member 102, a blanket shield layer 103 is provided so as to collectively cover the periphery of the tape member 102, and a jacket 104 is provided so as to cover the periphery of the collective shield layer 103. FIG. The number of coaxial cables 1 included in aggregate core 101 is not limited to the illustrated one, and aggregate core 101 includes electric wires (power supply lines, signal lines, etc.) having different structures from coaxial cables 1. good too.

(Summary of embodiment)
Next, technical ideas understood from the embodiments described above will be described with reference to the reference numerals and the like in the embodiments. However, each reference numeral and the like in the following description do not limit the constituent elements in the claims to the members and the like specifically shown in the embodiment.

[1] A conductor (2), an insulator (3) that surrounds the conductor (2), a shield layer (4) that surrounds the insulator (3), and a periphery of the shield layer (4) and a sheath (5) covering the insulator (3), wherein the shield layer (4) spirals a plurality of metal wires (411) having an elliptical cross-sectional shape perpendicular to the longitudinal direction around the insulator (3) A coaxial cable (1) having a horizontally wound shield part (41) wound in a shape and a batch plated part (42) made of conductive plating covering the circumference of the horizontally wound shield part (41). .

[2] A conductor (2), an insulator (3) surrounding the conductor (2), a shield layer (4) surrounding the insulator (3), and a circumference of the shield layer (4) and a sheath (5) covering the shield layer (4) is a horizontally wound shield portion ( 41), and a collectively plated portion (42) made of conductive plating that covers the periphery of the laterally wound shield portion (41), and the plurality of metal wires (411) are formed of the metal wires. A coaxial cable (1), which is a rectangular metal wire having a rectangular cross-sectional shape perpendicular to the longitudinal direction and an arc-shaped outer edge along the cable circumferential direction.

[3] The metal wire (411) has a cross-sectional shape perpendicular to the longitudinal direction of the metal wire (411) by the following formula: ellipticity = (major axis - minor axis) / major axis x 100%
The coaxial cable (1) according to [1], which is an ellipse satisfying 35% or more and 50% or less in the ellipticity obtained in .

[4] The collectively plated portion (42) is located radially outside the center of each of the plurality of metal wires (411) forming the laterally wound shield portion (41) in a cross section perpendicular to the longitudinal direction of the cable. A coaxial cable (1) according to any one of [1] to [3], wherein the coaxial cable (1) is formed only in

[5] The coaxial cable (1) according to any one of [1] to [4], wherein the metal wire (411) is a silver-plated wire.

[6] A multicore cable (100) comprising at least one coaxial cable (1) according to any one of [1] to [5].

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the scope of claims. Also, it should be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention. Moreover, the present invention can be modified appropriately without departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1... Coaxial cable 2... Conductor 3... Insulator 4... Shield layer 5... Sheath 41... Horizontal shield part 411... Metal wire 42... Batch plating part

Claims (6)

a conductor;
an insulator surrounding the conductor;
a shield layer surrounding the insulator;
a sheath that surrounds the shield layer,
The shield layer includes a horizontally wound shield portion configured by spirally winding a plurality of metal wires having an elliptical cross section perpendicular to the longitudinal direction around the insulator, and a periphery of the horizontally wound shield portion. and a collective plating portion made of conductive plating covering the
coaxial cable. a conductor;
an insulator surrounding the conductor;
a shield layer surrounding the insulator;
a sheath that surrounds the shield layer,
The shield layer includes a horizontally-wound shield portion configured by spirally winding a plurality of metal wires around the insulator, and a batch-plated portion made of hot-dip plating that covers the periphery of the horizontally-wound shield portion. have
The plurality of metal wires are rectangular metal wires having a rectangular cross-sectional shape perpendicular to the longitudinal direction of the metal wires and an arc-shaped outer edge along the cable circumferential direction.
coaxial cable. In the plurality of metal wires, the cross-sectional shape perpendicular to the longitudinal direction of the metal wires is the following formula: ellipticity = (major axis - minor axis) / major axis x 100%
An elliptical metal wire having an ellipticity of 35% or more and 50% or less obtained by
A coaxial cable according to claim 1 . The collectively plated portion is formed only outside the center of each of the plurality of metal wires constituting the laterally wound shield portion in the cable radial direction in a cross section perpendicular to the longitudinal direction of the cable,
A coaxial cable according to any one of claims 1 to 3. The metal wire is a silver-plated wire,
A coaxial cable according to any one of claims 1 to 4. At least one coaxial cable according to any one of claims 1 to 5,
multicore cable.

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