Compressed stranded wire conductor, cable using the same, and connection structure

Abstract

The present invention provides a compressed stranded wire conductor that is easy to manufacture and has improved electrical properties, as well as a cable and connection structure using the same. [Solution] The compressed stranded wire conductor 1 has an outer diameter of 0.1 mm or less and comprises a first metal part 2 having a central part 21 and a plurality of peripheral parts 22 twisted spirally around the central part 21, with the central part 21 and the plurality of peripheral parts 22 fitting together to form a circular cross-section as a whole, and a second metal part 3 made of a metal with higher conductivity than the first metal part 2 and covering each of the central part 21 and the plurality of peripheral parts 22, with the central part 21 and the plurality of peripheral parts 22, and adjacent peripheral parts 22, in close contact with each other with the second metal part 3 in between.

Description

Technical Field

[0001] The present invention relates to a compressed stranded conductor, a cable using the same, and a connection structure.

Background Art

[0002] In recent years, cables containing a large number of electric wires, for example, 100 or more, have been used. In the electric wires used in such cables, very thin conductors with an outer diameter of, for example, 0.1 mm or less have been used.

[0003] As prior art document information related to the invention of this application, there are Patent Documents 1 and 2.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When using, for example, a single wire conductor as the above-mentioned thin conductor, although the electrical characteristics are good, it is easily broken when subjected to operations such as bending and twisting. Therefore, in order to enhance the resistance to bending and the like, it is desirable to use a stranded conductor in which a plurality of metal strands are twisted as the above-mentioned thin conductor. However, in this case, since the contact area between the metal strands is small, the electrical characteristics deteriorate, and the outer diameter of the conductor also increases in order to secure the desired conductor cross-sectional area.

[0006] To address these challenges, one could consider using compressed stranded conductors. By using compressed stranded conductors, the contact area between metal strands can be increased, improving electrical properties, and the outer diameter can also be reduced. However, when manufacturing extremely thin compressed stranded conductors with an outer diameter of 0.1 mm or less, there is a challenge in that the metal strands are prone to breakage during compression, making manufacturing difficult. Furthermore, although compressed stranded conductors can improve electrical properties, their electrical properties are inferior to those of single-strand conductors, so further improvement in electrical properties is desirable.

[0007] Therefore, the present invention aims to provide a compressed stranded wire conductor that is easy to manufacture and has improved electrical properties, as well as a cable and connection structure using the same. [Means for solving the problem]

[0008] The present invention aims to solve the above problems and provides a compressed stranded wire conductor comprising: a first metal part having an outer diameter of 0.1 mm or less, a central part, and a plurality of peripheral parts twisted spirally around the central part, wherein the central part and the plurality of peripheral parts are fitted together to form a circular cross-section as a whole; and a second metal part made of a metal with higher conductivity than the first metal part, covering the central part and the plurality of peripheral parts, wherein the central part and the plurality of peripheral parts, and adjacent peripheral parts, are in close contact with each other across the second metal part.

[0009] Furthermore, the present invention aims to solve the above problems by providing a cable comprising at least the compressed stranded conductor and a sheath covering the periphery of the compressed stranded conductor.

[0010] Furthermore, the present invention aims to solve the above problems and provides a connection structure in which a conductor and an electrode formed on a substrate are connected by solder, wherein the conductor has an outer diameter of 0.1 mm or less and comprises a central part and a plurality of peripheral parts twisted spirally around the central part, the central part and the plurality of peripheral parts are fitted together to form a circular cross-section as a whole, and a second metal part made of a metal with higher conductivity than the first metal part and covering the central part and the plurality of peripheral parts, the central part and the plurality of peripheral parts and adjacent peripheral parts are in close contact with the second metal part in between, and the present invention provides a connection structure in which the solder does not penetrate into the interior of the compressed stranded conductor. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a compressed stranded wire conductor that is easy to manufacture and has improved electrical properties, as well as a cable and connection structure using the same. [Brief explanation of the drawing]

[0012] [Figure 1] (a) is a schematic cross-sectional view showing a cross-section perpendicular to the longitudinal direction of a compressed stranded conductor according to one embodiment of the present invention, and (b) is a photograph showing a cross-section perpendicular to the longitudinal direction of the compressed stranded conductor. [Figure 2] This is a cross-sectional view showing a section perpendicular to the longitudinal direction of a cable according to one embodiment of the present invention. [Figure 3] (a) is a cross-sectional view showing a cross-section perpendicular to the longitudinal direction of a multi-core cable, which is a cable according to one embodiment of the present invention, and (b) is a cross-sectional view of the strands constituting the multi-core cable. [Figure 4] (a) is a plan view showing a connection structure according to one embodiment of the present invention, and (b) is a photograph showing a cross-section of the connection portion between the compressed stranded conductor and the electrode. [Figure 5] For comparison with the present invention, this is a photograph showing a cross-section of the connection point between a stranded conductor, which consists of seven metal wires concentrically twisted together, and an electrode. [Modes for carrying out the invention]

[0013] [Embodiment] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0014] Figure 1(a) is a schematic cross-sectional view showing a cross-section perpendicular to the longitudinal direction of the compressed stranded conductor 1 according to this embodiment, and Figure 1(b) is a photograph showing a cross-section perpendicular to the longitudinal direction of the compressed stranded conductor 1. The compressed stranded conductor 1 has an outer diameter of 0.1 mm (38 AWG) or less, which is very small. In order to accommodate the multi-core and miniaturization of cables, even smaller diameter conductors are required, and the outer diameter of the compressed stranded conductor 1 is more preferably 0.061 mm (43 AWG) or less.

[0015] As shown in Figures 1(a) and 1(b), the compressed stranded conductor 1 comprises a first metal part 2 and a second metal part 3, which are made of different metal materials. The second metal part 3 is made of a metal with higher conductivity than the first metal part 2. In this embodiment, the first metal part 2 is made of copper or a copper alloy, and the second metal part 3 is made of silver. Because copper alloys and silver have high adhesion, delamination is less likely to occur during the compression process described later, and wire breakage due to delamination is also less likely to occur. In addition, because silver has high conductivity, using it as the second metal part 3 has the advantage of greatly improving the electrical characteristics (attenuation characteristics) of the compressed stranded conductor 1.

[0016] In this embodiment, as the first metal part 2, a copper alloy containing silver, indium, and tin in copper is used. As a result, even when the diameter is reduced, it becomes difficult to break the wire, and it is possible to maintain a sufficiently high conductivity (for example, about 85%). Note that as the copper serving as the base of the copper alloy constituting the first metal part 2, it is desirable to use pure copper with a purity of 99.99% or more. By using such pure copper, disconnection caused by impurities in the copper alloy can be suppressed. Since the first metal part 2 has a very small diameter and is compressed, it is easily affected by impurities. Therefore, it is particularly effective to use pure copper with a purity of 99.99% or more as the copper serving as the base of the copper alloy constituting the first metal part 2. Note that even when copper is used as the first metal part 2, in order to make it difficult to break the wire even when the diameter is reduced, it is desirable to use pure copper such as oxygen-free copper with a purity of 99.99% or more.

[0017] In this embodiment, a copper alloy is used for the first metal part 2 and silver is used for the second metal part 3. However, the present invention is not limited to this. If the conductivity of the second metal part 3 is higher than that of the first metal part 2, an appropriate metal material may be selected. For example, it is also possible to use a copper alloy for the first metal part 2 and copper (pure copper) for the second metal part 3.

[0018] The first metal part 2 includes a central part 21 disposed at the center of the conductor and a plurality of peripheral parts 22 spirally twisted around the central part 21. Here, six peripheral parts 22 are disposed around one central part 21. The central part 21 has a substantially hexagonal shape in a cross-sectional view perpendicular to the longitudinal direction (hereinafter, simply referred to as a cross-sectional view), and each peripheral part 22 is formed in a substantially fan shape extending radially outward from the six sides of the central part 21. The central part 21 and each peripheral part 22 are fitted to each other to form a circular cross-section as a whole.

[0019] The second metal part 3 covers each of the central part 21 and a plurality (here, six) of peripheral parts 22. The central part 21, the plurality of peripheral parts 22, and the peripheral parts 22 adjacent to each other in the circumferential direction are in close contact with each other with the second metal part 3 interposed therebetween. As a result, the second metal part 3 having a higher conductivity is filled in a strip shape between the first metal parts 2, so that the conductivity of the entire compressed stranded conductor 1 is improved and the electrical characteristics are improved. For example, even when transmitting a high-frequency signal in which the skin effect appears, the electrical characteristics are less likely to deteriorate due to the second metal part 3 having a high conductivity. Further, since the first metal part 2 is covered with the second metal part 3, disconnection is less likely to occur in the compression process described later, so that manufacturing becomes easier even if the diameter is reduced.

[0020] The compressed stranded conductor 1 is formed by using seven metal strands 4 in which the second metal part 3 is covered around the first metal part 2. That is, the second metal part 3 is a plating layer that covers the periphery of the first metal part 2. In the present embodiment, a silver-plated copper alloy wire provided with the second metal part 3 made of silver plating around the first metal part 2 made of a copper alloy is used as the metal strand 4.

[0021] When manufacturing the compressed stranded conductor 1, first, seven metal strands 4 are concentrically twisted, and after performing heat treatment (for example, temperature 300 ° C, wire speed 80 m / min) on the obtained twisted wire, the twisted wire is passed through a die to perform a compression process. The heat treatment before compression is performed to make the metal strands 4 easier to deform and to reduce the occurrence of disconnection in the compression process. In particular, in the present embodiment, since compression is performed with high strength to such an extent that the metal strands 4 are in close contact with each other almost without gaps, the heat treatment before compression is essential. In the compression process, for example, it may be adjusted so that the tensile strength is 500 MPa or more and 650 MPa or less and the elongation is about 1%. Thereafter, heat treatment is performed again (for example, temperature about 600 ° C, wire speed 70 m / min or less). As a result, the strain imparted in the compression process is removed, and accordingly, the decrease in conductivity due to the strain is eliminated, and the conductivity of the compressed stranded conductor 1 is improved. As described above, the compressed stranded conductor 1 is obtained.

[0022] Furthermore, if a metal wire 4 consisting only of the first metal part 2 without the second metal part 3 is used, an oxide film will form on the surface of the first metal part 2 during the heat treatment before compression. This oxide film will reduce the conductivity of the compressed stranded conductor 1 and also deteriorate its appearance. In addition, if a metal wire 4 consisting only of the first metal part 2 is used, scratches may occur on the surface of the metal wire 4 due to friction with the die during the compression process, making it easier for the wire to break starting from these scratches. In contrast, in this embodiment, a metal wire 4 with the second metal part 3 covering the first metal part 2 is used, so there is no risk of an oxide film forming during heat treatment, and a good appearance can be maintained. Also, during the compression process, the second metal part 3 acts as a protective layer that protects the surface of the first metal part 2, making it less likely for the wire to break.

[0023] In the compressed stranded wire conductor 1 according to this embodiment, the ratio of the cross-sectional area occupied by the second metal portion 3 to the total cross-sectional area in a cross-section perpendicular to the longitudinal direction is preferably 10% or more. This increases the proportion of the second metal portion 3, which has high conductivity, thereby improving the overall conductivity of the compressed stranded wire conductor 1 and improving its electrical characteristics.

[0024] Furthermore, the inventors have found that when forming a very small diameter compressed stranded wire conductor 1 with an outer diameter of 0.1 mm or less, as in this embodiment, the ratio of the cross-sectional areas of the first metal part 2 and the second metal part 3 changes before and after the compression process. More specifically, it was found that the ratio of the cross-sectional area occupied by the second metal part 3 to the total cross-sectional area becomes larger after the compression process than before the compression process (i.e., the ratio of the cross-sectional area occupied by the first metal part 2 to the total cross-sectional area becomes smaller). This is thought to be because, when the first metal part 2, which is relatively hard and where stress is more concentrated, is stretched more than the second metal part 3, which is relatively softer, while being stretched and compressed through the die during the compression process.

[0025] As an example, we will describe the case where seven metal strands 4, each having an outer diameter of 0.045 mm and a second metal part 3 (plating layer) thickness of 1 μm or less, are twisted together to form compressed stranded conductors 1 with outer diameters of 0.092 mm and 0.089 mm (38 AWG). Before compression, the ratio of the cross-sectional area of ​​the second metal part 3 to the total cross-sectional area of ​​the compressed stranded conductor 1 is approximately 4.4% or less. In contrast, Table 1 shows the measurement results of the cross-sectional area of ​​the compressed stranded conductor 1 actually manufactured. In Examples 1 and 2, the outer diameter was 0.092 mm, and in Examples 3 and 4, the outer diameter was 0.089 mm. In Examples 1 and 3, the line speed was 50 m / min, and in Examples 2 and 4, the line speed was 20 m / min. The cross-sectional area of ​​the compressed stranded conductor 1 was measured by image analysis using a microscope. Specifically, the cross-section of the compressed stranded conductor 1 was photographed using a microscope (Keyence VHX-5000), and the captured image was analyzed using the microscope's area measurement function to measure the cross-sectional area of ​​the central part 21 and surrounding part 22 of the first metal part 2, and the cross-sectional area of ​​the second metal part 3.

[0026] [Table 1]

[0027] As shown in Table 1, in all of Examples 1 to 4, the ratio of the cross-sectional area occupied by the second metal part 3 to the total cross-sectional area is 10% or more. Also, from Table 1, it can be seen that in the first metal part 2, the cross-sectional area of ​​the central part 21 is smaller than the average value of the cross-sectional areas of the multiple surrounding parts 22. This is thought to be because the compressive stress was concentrated in the central part 21. The cross-sectional area of ​​the central part 21 should be between 92% and 95% of the average value of the cross-sectional areas of the multiple surrounding parts 22. By applying stress and compressing so that the cross-sectional area of ​​the central part 21 and the cross-sectional areas of the multiple surrounding parts 22 are in this ratio, the adhesion between the first metal part 2 and the second metal part 3 can be improved, and the area of ​​the void 5 can be reduced.

[0028] Furthermore, if the proportion of the second metal part 3, which is the plating layer, becomes too large, it may lead to a decrease in mechanical strength. Therefore, in a cross-section perpendicular to the longitudinal direction, the ratio of the cross-sectional area occupied by the second metal part 3 to the total cross-sectional area should be 15% or less.

[0029] Furthermore, in this embodiment, the thickness of the second metal portion 3 is greater than the thickness of the outer surface of the compressed stranded conductor 1 (conductor outer surface) at least between the multiple peripheral portions 22. This is because there are two layers of the second metal portion 3 between the peripheral portions 22, while there is only one layer of the second metal portion 3 on the outer surface of the compressed stranded conductor 1.

[0030] Furthermore, it is desirable that the compressed stranded conductor 1 is compressed so that there are virtually no gaps between the metal strands 4, and in a cross section perpendicular to the longitudinal direction, the ratio of the area of ​​the air gap 5 to the area of ​​the circumscribed circle of the conductor, which is the circumscribed circle that circumscribes the compressed stranded conductor 1, should be 1.5% or less. As a result, each metal strand 4 is in close contact with each other without gaps (in surface contact), improving electrical properties and suppressing unintentional unraveling of the strands during terminal processing, thereby improving workability during terminal processing. In addition, since the amount of air present between the metal strands 4 is extremely small, voids are less likely to occur when soldering the compressed stranded conductor 1 to electrodes, etc. (this point will be discussed later). Since the metal strands 4 are not bonded to each other, each metal strand 4 can move relative to each other in the longitudinal direction when subjected to actions such as bending, twisting, shaking, and rubbing (referred to as bending and other actions), and has high resistance to bending and other actions.

[0031] (Cable 10) Figure 2 is a cross-sectional view showing a section perpendicular to the longitudinal direction of the cable 10 according to this embodiment. As shown in Figure 2, the cable 10 uses the compressed stranded wire conductor 1 according to this embodiment as its conductor, and comprises at least the compressed stranded wire conductor 1 and a sheath covering the periphery of the compressed stranded wire conductor 1. In the example in Figure 2, the cable 10 is shown as a coaxial cable in which an insulator 11, a shield layer 12, and a jacket layer 13 are sequentially provided around the compressed stranded wire conductor 1. In this case, the outermost jacket layer 13 corresponds to the sheath.

[0032] The insulator 11 is formed to surround the compressed stranded wire conductor 1, which is the central conductor. Here, the case where the insulator 11 is a single layer is shown, but it is not limited to this, and the insulator 11 may be composed of multiple layers. In this case, the insulator 11 may have a foamed layer made of foamed resin that surrounds the compressed stranded wire conductor 1, and a non-foamed skin layer that surrounds the foamed layer. By having a foamed layer, the dielectric constant of the insulator 11 can be reduced, which can improve the electrical characteristics, especially when transmitting high-frequency signals. Because the foamed layer has air bubbles, insulation between the compressed stranded wire conductor 1 and the shield layer 12 can be ensured by covering it with a non-foamed skin layer.

[0033] The shield layer 12 consists of a horizontally wound shield in which multiple metal wires 12a are spirally wound around the insulator 11. The metal wires 12a are made of copper or a copper alloy. The metal wires 12a may be plated with silver, tin, or the like on their surface. In order to increase the conductivity and mechanical strength of the shield layer 12, it is desirable to use metal wires 12a made of silver-plated copper alloy.

[0034] The jacket layer 13 is provided so as to cover the periphery of the shield layer 12. The jacket layer 13 may be constructed, for example, by wrapping a resin tape around it. More specifically, for example, the jacket layer 13 may be made up of two layers, with the first layer being made by spirally wrapping a non-adhesive resin tape so that a portion of the width overlaps, and the second layer being made by using an adhesive resin tape with a hot-melt adhesive layer on one side of the resin layer, and spirally wrapping the resin tape with the adhesive layer facing inward so that a portion of the width overlaps. After that, the adhesive layer can be melted by heating to bond it to the first layer of non-adhesive resin tape, thereby forming the jacket layer 13. As the resin that makes up the resin tape, PET (polyethylene terephthalate), PI (polyimide), PEEK (polyether ether ketone), PEI (polyetherimide), etc. can be used.

[0035] Here, the case where cable 10 is a coaxial cable has been described, but the specific structure of cable 10 is not limited to that shown in the illustration. For example, it may be an insulated wire in which an insulator 11 is provided around a compressed stranded conductor 1.

[0036] Furthermore, as shown in Figures 3(a) and (b), the cable 10 may also be a multi-core cable 10a using a compressed stranded wire conductor 1 as the core conductor. In the example in Figure 3, the multi-core cable 10a comprises a cable core 15 formed by twisting together 12 sub-stranded wires 14, which are made by twisting together 16 of the cable 10 (coaxial cable) shown in Figure 2, a binding tape 16 wrapped around the cable core 15, a single shield layer 17 covering the binding tape 16, and a sheath 18 covering the single shield layer 17.

[0037] The cable core 15 is constructed by twisting together three strands 14 and then twisting nine more strands 14 around them. The twisting direction in each layer of the cable core 15 is the same. The binding tape 16 is spirally wrapped around the cable core 15 so that a portion of its width overlaps with the tape. The single shield layer 17 consists of a braided shield made by braiding together multiple strands. The sheath 18 is preferably formed by tube extrusion so that the resin constituting the sheath 18 does not get into the spaces between the strands of the single shield layer 17.

[0038] (Connection structure 100) Figure 4(a) is a plan view showing the connection structure 100 according to this embodiment, and Figure 4(b) is a photograph showing a cross-section of the connection portion between the compressed stranded wire conductor 1 and the electrode 102.

[0039] As shown in Figure 4(a), the connection structure 100 is constructed by connecting the compressed stranded conductor 1 and the electrodes 102 formed on the substrate 101 with solder 104. The illustrated example shows the case where multiple cables 10 (coaxial cables) from Figure 2 are connected to the substrate 101. The substrate 101 has multiple electrodes 102 (signal electrodes) corresponding to the compressed stranded conductor 1 of each cable 10, and a common ground electrode 103 for each cable 10. The multiple electrodes 102 are arranged perpendicular to the extension direction of the cable 10, and the ground electrode 103 is formed on the extension side of the cable 10, further than the multiple electrodes 102.

[0040] At the end of the cable 10, the shield layer 12 is exposed from the end of the jacket layer 13, the insulator 11 is exposed from the end of the shield layer 12, and the compressed stranded conductor 1 is exposed from the end of the insulator 11. The shield layer 12 of each cable 10 is collectively connected to a common ground electrode 103 by solder 105, and the compressed stranded conductor 1 of each cable 10 is connected to the corresponding electrode 102 by solder 104.

[0041] As shown in Figure 4(b), the compressed stranded conductor 1 maintains a state in which the central part 21 and multiple peripheral parts 22, and adjacent peripheral parts 22, are in close contact with each other, with the second metal part 3 in between. The compressed stranded conductor 1 is less likely to unravel during terminal processing and can easily maintain its cross-sectional shape. Therefore, the solder 104 does not penetrate into the interior of the compressed stranded conductor 1, and the solder 104 is evenly soldered so as to surround the outer surface of the compressed stranded conductor 1. As a result, voids (air bubbles) are less likely to form in the solder 104, and the compressed stranded conductor 1 is less likely to come loose from the solder 104, resulting in high connection reliability. In addition, because the cross-sectional shape of the compressed stranded conductor 1 is less likely to be disturbed, it is possible to easily make the surface of the solder 104 into a clean arc shape.

[0042] In contrast, with a stranded conductor made by simply twisting seven metal strands 4 concentrically, as shown in Figure 5, for example, solder 104 can easily seep between the metal strands 4, disrupting their arrangement and making voids 106 more likely to occur. As a result, variations in the degree to which the metal strands 4 are fixed can occur, and if a pulling force is applied to the conductor for any reason, the stranded conductor may come loose from the solder 104, or stress may concentrate on only some of the metal strands 4, causing a break in the connection, resulting in low connection reliability. Furthermore, the disruption of the metal strands 4 also disrupts the surface of the solder 104, making it difficult for the surface of the solder 104 to form a clean arc shape, thus degrading its appearance.

[0043] Furthermore, in the connection structure 100 according to this embodiment, the twist of the compressed stranded conductor 1 is less likely to unravel, thus reducing the area required for soldering (to the same extent as when using a single-wire conductor). As a result, it becomes possible to connect multiple compressed stranded conductors 1 in parallel at a narrow pitch, contributing to higher wiring density and miniaturization of equipment using the circuit board 101. In addition, in the connection structure 100 according to this embodiment, the compressed stranded conductor 1 can maintain its cross-sectional shape during terminal processing, thus reducing the variation in capacitance values ​​of multiple cables 10 (coaxial cables). This improves the quality of signals transmitted through multiple cables 10. Moreover, when including a large number of cables 10, such as 100 or more, tuning to adjust capacitance becomes easier.

[0044] (Operation and Effects of the Embodiment) As described above, the compressed stranded wire conductor 1 according to this embodiment has an outer diameter of 0.1 mm or less and comprises a first metal part 2 having a central part 21 and a plurality of peripheral parts 22 twisted spirally around the central part 21, with the central part 21 and the plurality of peripheral parts 22 fitting together to form a circular cross-section as a whole, and a second metal part 3 made of a metal with higher conductivity than the first metal part 2 and covering each of the central part 21 and the plurality of peripheral parts 22, and the central part 21 and the plurality of peripheral parts 22, and adjacent peripheral parts 22 to each other are in close contact with the second metal part 3 in between.

[0045] This configuration results in a cross-sectional view showing the highly conductive second metal portion 3 arranged in a streaky pattern, thereby increasing the overall conductivity of the compressed stranded conductor 1 and improving its electrical properties. Furthermore, by using a metal wire 4 in which the first metal portion 2 is covered by the second metal portion 3, the second metal portion 3 acts as a protective layer, making it possible to realize a compressed stranded conductor 1 that is small in diameter yet less prone to breakage during manufacturing. While it is conceivable to manufacture with low tension to prevent breakage, this would make tension adjustment difficult, increasing the difficulty of manufacturing and making it difficult to obtain the desired electrical properties. According to this embodiment, even when manufactured with a relatively high tension, breakage is less likely to occur, thus enabling the realization of a compressed stranded conductor 1 that is easy to manufacture and has good productivity.

[0046] (Summary of the embodiments) Next, the technical concept understood from the embodiments described above will be described using the reference numerals and other symbols from the embodiments. However, the reference numerals and other symbols in the following description are not limited to the components in the claims that are specifically shown in the embodiments.

[0047] [1] A compressed stranded wire conductor (1) having an outer diameter of 0.1 mm or less, comprising a first metal part (2) having a central part (21) and a plurality of peripheral parts (22) twisted spirally around the central part (21), wherein the central part (21) and the plurality of peripheral parts (22) are fitted together to form a circular cross-section as a whole, and a second metal part (3) made of a metal with higher conductivity than the first metal part (2) covering the central part (21) and the plurality of peripheral parts (22), wherein the central part (21) and the plurality of peripheral parts (22), and adjacent peripheral parts (22) are in close contact with each other with the second metal part (3) in between.

[0048] [2] The compressed stranded wire conductor (1) according to [1], wherein in a cross section perpendicular to the longitudinal direction, the ratio of the cross-sectional area occupied by the second metal part (3) to the total cross-sectional area is 10% or more.

[0049] [3] The compressed stranded wire conductor (1) according to [1], wherein in a cross section perpendicular to the longitudinal direction, the ratio of the cross-sectional area occupied by the second metal part (3) to the total cross-sectional area is 15% or less.

[0050] [4] The compressed stranded wire conductor (1) according to [1], wherein in a cross section perpendicular to the longitudinal direction, the cross-sectional area of ​​the central part (21) is smaller than the average value of the cross-sectional areas of the plurality of surrounding parts (22).

[0051] [5] The second metal portion (3) is a compressed stranded wire conductor (1) according to [1], wherein the thickness between at least the multiple peripheral portions (22) is greater than the thickness on the outer surface of the conductor.

[0052] [6] The compressed stranded wire conductor (1) according to [1], wherein the first metal part (2) is made of copper or a copper alloy and the second metal part (3) is made of silver.

[0053] [7] The compressed stranded wire conductor (1) according to [1], wherein the first metal part (2) is made of a copper alloy and the second metal part (3) is made of copper.

[0054] [8] A compressed stranded wire conductor (1) as described in [1], having an outer diameter of 0.061 mm or less.

[0055] [9] The compressed stranded wire conductor (1) according to [1], wherein in a cross section perpendicular to the longitudinal direction, the ratio of the area of ​​the void (5) to the area of ​​the circumscribed circle of the conductor is 1.5% or less.

[0056]

[10] A cable (10, 10a) comprising at least a compressed stranded conductor (1) as described in any one of [1] to [9], and a sheath (jacket layer 13, sheath 18) covering the compressed stranded conductor (1).

[0057]

[11] A connection structure (100) in which a conductor and an electrode (102) formed on a substrate (101) are connected by solder (104), wherein the conductor has an outer diameter of 0.1 mm or less and has a central part (21) and a plurality of peripheral parts (22) twisted spirally around the central part (21), and the central part (21) and the plurality of peripheral parts (22) are fitted together to form a first metal part (2) which as a whole has a circular cross-section, and the first A compressed stranded wire conductor (1) comprising a second metal part (3) made of a metal with higher conductivity than the metal part (2), covering the central part (21) and each of the multiple peripheral parts (22), wherein the central part (21) and the multiple peripheral parts (22), and adjacent peripheral parts (22) are in close contact with each other with the second metal part (3) in between, and the connection structure (100) wherein the solder (104) does not penetrate into the interior of the compressed stranded wire conductor (1).

[0058] (Note) Although embodiments of the present invention have been described above, the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention. In addition, the present invention can be implemented with appropriate modifications without departing from its spirit. [Explanation of symbols]

[0059] 1... Compressed stranded conductor 2...First metal part 21…Center 22... Surrounding area 3…Second metal part 4… Metal wire 5...Void 10… Cable 10a…Multi-core cable 100…Connection structure 101... Circuit board 102...Electrode 104... Handa

Claims

1. The outer diameter is 0.1 mm or less. A first metal part having a central part and a plurality of peripheral parts twisted spirally around the central part, wherein the central part and the plurality of peripheral parts are fitted together to form a circular cross-section as a whole, It comprises a second metal part made of a metal with higher conductivity than the first metal part, and covering the central part and each of the multiple surrounding parts, The central part and the multiple surrounding parts, and adjacent surrounding parts, are in close contact with each other, with the second metal part in between. Compressed stranded conductor.

2. In a cross-section perpendicular to the longitudinal direction, the ratio of the cross-sectional area occupied by the second metal part to the total cross-sectional area is 10% or more. The compressed stranded wire conductor according to claim 1.

3. In a cross-section perpendicular to the longitudinal direction, the ratio of the cross-sectional area occupied by the second metal part to the total cross-sectional area is 15% or less. The compressed stranded wire conductor according to claim 1.

4. In a cross-section perpendicular to the longitudinal direction, the cross-sectional area of ​​the central part is smaller than the average value of the cross-sectional areas of the multiple surrounding parts. The compressed stranded wire conductor according to claim 1.

5. The second metal portion has a thickness greater than the thickness on the outer surface of the conductor, at least between the multiple peripheral portions. The compressed stranded wire conductor according to claim 1.

6. The first metal part is made of copper or a copper alloy. The second metal part is made of silver. The compressed stranded wire conductor according to claim 1.

7. The first metal part is made of a copper alloy, The second metal part is made of copper. The compressed stranded wire conductor according to claim 1.

8. The outer diameter is 0.061 mm or less. The compressed stranded wire conductor according to claim 1.

9. In a cross-section perpendicular to the longitudinal direction, the ratio of the area of ​​the void to the area of ​​the circumscribed circle of the conductor is 1.5% or less. The compressed stranded wire conductor according to claim 1.

10. at least, A compressed stranded wire conductor according to any one of claims 1 to 9, A sheath covering the periphery of the compressed stranded conductor, cable.

11. A connection structure in which a conductor and an electrode formed on a substrate are connected by solder, The aforementioned conductor is The outer diameter is 0.1 mm or less. A first metal part having a central part and a plurality of peripheral parts twisted spirally around the central part, wherein the central part and the plurality of peripheral parts are fitted together to form a circular cross-section as a whole, It comprises a second metal part made of a metal with higher conductivity than the first metal part, and covering the central part and each of the multiple surrounding parts, The central part and the multiple peripheral parts, and adjacent peripheral parts, are in close contact with each other across the second metal part, forming a compressed stranded conductor. The solder has not penetrated into the interior of the compressed stranded conductor. Connection structure.

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