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

Abstract

The invention provides a compressed stranded wire conductor, a cable using the same, and a connection structure. The outer diameter of the compressed stranded wire conductor (1) is less than 0.1 mm, and the compressed stranded wire conductor (1) is provided with a first metal part (2) and a second metal part (3). The first metal part (2) has a central part (21) and a plurality of peripheral parts (22) twisted in a spiral shape around the central part (21), and the central part (21) and the plurality of peripheral parts (22) are embedded with each other to form a circular cross section as a whole; a second metal part (3) made of a metal having a higher conductivity than that of the first metal part (2) and covering the central part (21) and each of the plurality of peripheral parts (22); the central portion (21) and the plurality of peripheral portions (22), and adjacent peripheral portions (22) are in close contact with each other with a second metal portion (3) therebetween.

Description

Technical Field

[0001] This invention relates to compressed stranded conductors, cables using them, and connection structures. Background Technology

[0002] In recent years, for example, cables containing more than 100 wires have been used, and in the wires used in such cables, conductors with an outer diameter of less than 0.1 mm are used.

[0003] It should be noted that, as prior art information related to this invention, there are patent documents 1 and 2.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2000-4604

[0007] Patent Document 2: Japanese Patent Application Publication No. 2015-167092 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] As described above, thin-diameter conductors, such as single-wire conductors, while exhibiting good electrical properties, are prone to breakage when subjected to bending, twisting, or other actions. Therefore, to improve resistance to bending and other forces, stranded conductors, consisting of multiple bare metal wires twisted together, are desirable for thin-diameter conductors. However, in this case, the electrical properties deteriorate due to the small contact area between the bare metal wires, necessitating a larger outer diameter to ensure the desired conductor cross-sectional area.

[0010] To address this issue, compressed stranded conductors, which are formed by compressing stranded conductors, can be considered. Using compressed stranded conductors increases the contact area between the bare metal wires, thus improving electrical properties. Additionally, the outer diameter can be reduced. However, when manufacturing very fine compressed stranded conductors with an outer diameter of 0.1 mm or less, issues arise such as easy breakage of the bare metal wires during compression and manufacturing difficulties. Furthermore, while using compressed stranded conductors improves electrical properties, their properties are still inferior to those of single-wire conductors, thus further improvements in electrical properties are desired.

[0011] Therefore, the object of the present invention is to provide a compressed stranded conductor that can be easily manufactured and has improved electrical characteristics, a cable using the compressed stranded conductor, and a connection structure.

[0012] Methods for solving problems

[0013] To address the aforementioned problems, this invention provides a compressed stranded conductor with an outer diameter of 0.1 mm or less and comprising a first metal portion and a second metal portion. The first metal portion has a central portion and a plurality of peripheral portions spirally stranded around the central portion, wherein the central portion and the plurality of peripheral portions are interlocked to form a circular cross-section. The second metal portion is made of a metal with a higher conductivity than the first metal portion and covers the central portion and each of the plurality of peripheral portions. The central portion and the plurality of peripheral portions, as well as adjacent peripheral portions, are in close contact with each other by sandwiching the second metal portion.

[0014] In addition, to solve the above problems, the present invention provides a cable having at least the above-mentioned compressed stranded conductor and a sheath covering the compressed stranded conductor.

[0015] Furthermore, to address the aforementioned problems, the present invention provides a connection structure formed by connecting a conductor to an electrode formed on a substrate using solder; the conductor is a compressed stranded wire conductor with an outer diameter of 0.1 mm or less, and includes a first metal portion and a second metal portion; the first metal portion has a central portion and a plurality of peripheral portions spirally twisted around the central portion, the central portion and the plurality of peripheral portions interlocking to form a circular cross-section; the second metal portion is made of a metal with a higher conductivity than the first metal portion, and covers each of the central portion and the plurality of peripheral portions; the central portion and the plurality of peripheral portions, as well as adjacent peripheral portions, sandwich the second metal portion in close contact; the solder does not penetrate the interior of the compressed stranded wire conductor.

[0016] Invention Effects

[0017] According to the present invention, it is possible to provide a compressed stranded conductor that is easy to manufacture and achieves improved electrical characteristics, cables using the conductor, and connection structures. Attached Figure Description

[0018] Figure 1 In the figures, (a) is a cross-sectional view schematically showing a section perpendicular to the length direction of a compressed stranded conductor according to an embodiment of the present invention, and (b) is a photograph showing a section perpendicular to the length direction of the compressed stranded conductor.

[0019] Figure 2 This is a cross-sectional view showing a cable perpendicular to its length direction according to one embodiment of the present invention.

[0020] Figure 3 In the diagram, (a) is a cross-sectional view of a multi-core cable of an embodiment of the present invention, perpendicular to the length direction, and (b) is a cross-sectional view of the stranded wires constituting the multi-core cable.

[0021] Figure 4 In the image, (a) is a top view showing the connection structure of 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.

[0022] Figure 5 This photograph shows a cross-section of the connection between a stranded conductor, consisting of seven bare metal wires concentrically twisted together, and an electrode, for comparison with the present invention.

[0023] Explanation of reference numerals in the attached figures

[0024] 1…compressed stranded conductor, 2…first metal part, 21…center part, 22…peripheral part, 3…second metal part, 4…bare metal wire, 5…gap, 10…cable, 10a…multi-core cable, 100…connection structure, 101…substrate, 102…electrode, 104…solder. Detailed Implementation

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] Figure 1 (a) is a schematic cross-sectional view showing the section perpendicular to the length direction of the compressed stranded conductor 1 of this embodiment. Figure 1 (b) is a photograph showing a cross-section of the compressed stranded conductor 1 perpendicular to its length. The outer diameter of the compressed stranded conductor 1 is 0.1 mm (38 AWG) or less, which is very small. In order to meet the requirements of multi-core and small-diameter 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.

[0027] like Figure 1 (a) and Figure 1 As shown in (b), the compressed stranded conductor 1 includes a first metal portion 2 and a second metal portion 3 made of different metal materials. The second metal portion 3 is made of a metal with a higher conductivity than the first metal portion 2. In this embodiment, the first metal portion 2 is made of copper or a copper alloy, and the second metal portion 3 is made of silver. Since copper alloy and silver have high adhesion, peeling is less likely to occur during the compression process described later, and wire breakage caused by peeling is also less likely to occur. Furthermore, since silver has high conductivity, using it as the second metal portion 3 also has the advantage of significantly improving the electrical characteristics (attenuation characteristics) of the compressed stranded conductor 1.

[0028] In this embodiment, a copper alloy containing silver, indium, and tin is used as the first metal part 2. This reduces the likelihood of wire breakage even with a smaller diameter and maintains a sufficiently high conductivity (e.g., around 85%). It should be noted that copper, as the base material of the copper alloy constituting the first metal part 2, is prone to breakage if it contains many impurities; therefore, pure copper with a purity of 99.99% or higher is preferred. Furthermore, when using copper as the first metal part 2, oxygen-free copper or similar pure copper with a purity of 99.99% or higher is also preferred to prevent wire breakage even with a smaller diameter.

[0029] It should be noted that in this embodiment, the first metal part 2 is made of copper alloy and the second metal part 3 is made of silver, but this is not a limitation. As long as the conductivity of the second metal part 3 is higher than that of the first metal part 2, an appropriate metal material can be selected. For example, the first metal part 2 can be made of copper alloy and the second metal part 3 can be made of copper (pure copper).

[0030] The first metal portion 2 has a central portion 21 disposed at the center of the conductor and a plurality of peripheral portions 22 spirally interlocked around the central portion 21. Here, six peripheral portions 22 are disposed around the central portion 21. The central portion 21 is approximately hexagonal in shape in a cross section (hereinafter simply referred to as the cross section) perpendicular to the length direction, and each peripheral portion 22 is formed into a generally fan shape extending radially outward from the six sides of the central portion 21. Moreover, the central portion 21 and each peripheral portion 22 fit together to form a circular cross section as a whole.

[0031] The second metal portion 3 covers the central portion 21 and each of the plurality of (six in this case) peripheral portions 22. Furthermore, the central portion 21 and the plurality of peripheral portions 22, as well as adjacent peripheral portions 22 in the circumferential direction, are tightly fitted together by the second metal portion 3. Therefore, since the second metal portion 3, which has higher conductivity, fills the spaces between the first metal portions 2 in a stripe pattern, the conductivity of the entire compressed stranded conductor 1 is increased, and its electrical characteristics are improved. For example, even when transmitting high-frequency signals that generate a skin effect, the electrical characteristics are less likely to deteriorate due to the high conductivity of the second metal portion 3. In addition, because the first metal portion 2 is covered by the second metal portion 3, wire breakage becomes less likely during the compression process described later, thus facilitating manufacturing even with smaller diameters.

[0032] The compressed stranded conductor 1 is constructed using seven bare metal wires 4 that surround a second metal portion 3 around a first metal portion 2. That is, the second metal portion 3 is a plating layer covering the periphery of the first metal portion 2. In this embodiment, a silver-plated copper alloy wire with a silver-plated second metal portion 3 surrounding a first metal portion 2 made of copper alloy is used as the bare metal wire 4.

[0033] In manufacturing the compressed stranded conductor 1, firstly, seven bare metal wires 4 are concentrically stranded. The resulting stranded wire is then heat-treated (e.g., at a temperature of 300°C and a line speed of 80 m / min), and then compressed through a die. The heat treatment before compression is performed to make the bare metal wires 4 easily deformable and less prone to breakage during the compression process. In particular, in this embodiment, compression is performed with high strength until the bare metal wires 4 are almost seamlessly bonded together; therefore, heat treatment before compression is necessary. It should be noted that, during the compression process, the tensile strength can be adjusted to be, for example, 500 MPa or more and 650 MPa or less, with an elongation of approximately 1%. Afterward, another heat treatment is performed (e.g., at a temperature of approximately 600°C and a line speed of 70 m / min or less). Therefore, the strain imposed during the compression process is eliminated, thereby eliminating the decrease in conductivity caused by strain, and thus increasing the conductivity of the compressed stranded conductor 1. Thus, the compressed stranded conductor 1 can be obtained.

[0034] It should be noted that when using bare metal wire 4 consisting only of the first metal portion 2 and lacking the second metal portion 3, an oxide film is formed on the surface of the first metal portion 2 during the heat treatment before compression. Due to this oxide film, the conductivity of the compressed stranded conductor 1 decreases, and its appearance deteriorates. Furthermore, when using bare metal wire 4 consisting only of the first metal portion 2, if damage occurs on the surface of the bare metal wire 4 during the compression process due to friction with the mold, breakage is likely to occur starting from this damage. In contrast, in this embodiment, since bare metal wire 4 with the second metal portion 3 surrounding the first metal portion 2 is used, there is no concern about oxide film formation during heat treatment, and a good appearance can be maintained. Additionally, during the compression process, the second metal portion 3 also acts as a protective layer for the surface of the first metal portion 2, thus reducing the likelihood of breakage.

[0035] In the compressed stranded conductor 1 of this embodiment, the cross-sectional area occupied by the second metal portion 3 in a section perpendicular to the length direction can be 10% or more of the total cross-sectional area. This increases the proportion of the second metal portion 3 with high conductivity, thereby improving the overall conductivity of the compressed stranded conductor 1 and enhancing its electrical characteristics.

[0036] It should be noted that the inventors conducted research and found that when forming a very fine-diameter compressed stranded 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 portion 2 and the second metal portion 3 changes before and after the compression process. More specifically, it is known that compared to before the compression process, after the compression process, the proportion of the cross-sectional area occupied by the second metal portion 3 in the total cross-sectional area increases (i.e., the proportion of the cross-sectional area occupied by the first metal portion 2 in the total cross-sectional area decreases). This is believed to be because, during the compression process, when the first metal portion 2, which is harder and has higher stress concentration, is stretched more than the second metal portion 3, which is softer.

[0037] As an example, a compressed stranded conductor 1 with outer diameters of 0.092 mm and 0.089 mm (38AWG) is described by stranding seven bare metal wires 4, each with an outer diameter of 0.045 mm and a thickness of 1 μm or less for the second metal portion 3 (which serves as a plating layer), together. The ratio of the cross-sectional area of ​​the second metal portion 3 before compression to the total cross-sectional area of ​​the compressed stranded conductor 1 is approximately 4.4% or less. Table 1 shows the measurement results of the cross-sectional area of ​​the actually manufactured compressed stranded conductor 1. In Examples 1 and 2, the outer diameter was set to 0.092 mm; in Examples 3 and 4, the outer diameter was set to 0.089 mm; in Examples 1 and 3, the line speed was set to 50 m / min; and in Examples 2 and 4, the line speed was set to 20 m / min.

[0038] [Table 1]

[0039]

[0040] As shown in Table 1, it can be seen that in any of Embodiments 1 to 4, the cross-sectional area occupied by the second metal portion 3 accounts for 10% or more of the total cross-sectional area. Furthermore, according to Table 1, in the first metal portion 2, the cross-sectional area of ​​the central portion 21 is smaller than the average cross-sectional area of ​​the plurality of peripheral portions 22. This is believed to be because compressive stress is concentrated in the central portion 21. It is preferable that the cross-sectional area of ​​the central portion 21 is 92% or more and 95% or less of the average cross-sectional area of ​​the plurality of peripheral portions 22.

[0041] It should be noted that if the proportion of the second metal part 3 as the coating becomes too large, it may lead to a decrease in mechanical strength. Therefore, in a cross-section perpendicular to the length direction, the proportion of the cross-sectional area occupied by the second metal part 3 to the total cross-sectional area is preferably less than 15%.

[0042] Furthermore, in this embodiment, the thickness of the second metal portion 3 among the plurality of peripheral portions 22 is greater than the thickness of the outer peripheral surface (conductor outer peripheral surface) of the compressed stranded conductor 1. 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 peripheral surface of the compressed stranded conductor 1.

[0043] Furthermore, the compressed stranded conductor 1 is preferably compressed in such a way that there are almost no gaps between the bare metal wires 4. In a cross-section perpendicular to the length direction, the area of ​​the gap 5 relative to the area of ​​the circumcircle of the compressed stranded conductor 1 is preferably 1.5% or less. This results in the bare metal wires 4 being in close contact with each other without gaps (in a surface contact state), improving electrical characteristics and suppressing accidental unwinding during end processing, thus improving workability during end processing. Additionally, since the amount of air present between the bare metal wires 4 is extremely small, voids are less likely to form when the compressed stranded conductor 1 is brazed to electrodes, etc. (this will be discussed later). It should be noted that since the bare metal wires 4 are not bonded together, they can move relative to each other in the length direction when subjected to bending, twisting, oscillation, or diameter reduction compression (referred to as bending actions), exhibiting high resistance to bending actions.

[0044] (Cable 10)

[0045] Figure 2 This is a cross-sectional view showing the cable 10 of this embodiment, perpendicular to its length direction. (Example) Figure 2 As shown, the cable 10 uses the compressed stranded conductor 1 of this embodiment as its conductor, and at least has the compressed stranded conductor 1 and a sheath covering the compressed stranded conductor 1. Figure 2 In the example shown, cable 10 is a coaxial cable in which an insulator 11, a shielding layer 12, and an outer jacket 13 are sequentially arranged around a compressed stranded conductor 1. In this case, the outermost outer jacket 13 is equivalent to a sheath.

[0046] The insulator 11 is formed to cover the area surrounding the compressed stranded conductor 1, which serves as the central conductor. Here, a single layer of insulator 11 is shown, but it is not limited to this; the insulator 11 may also be composed of multiple layers. In this case, the insulator 11 may have a foamed layer made of foamed resin covering the compressed stranded conductor 1 and a non-foamed skin layer covering the area surrounding the foamed layer. By having a foamed layer, the dielectric constant of the insulator 11 can be reduced, and in particular, the electrical characteristics can be improved when transmitting high-frequency signals. Since the foamed layer contains air bubbles, insulation between the compressed stranded conductor 1 and the shielding layer 12 can be ensured by covering its area with a non-foamed skin layer.

[0047] The shielding layer 12 is composed of a transversely wound shielding element formed by spirally winding multiple bare metal wires 12a around the insulator 11. The bare metal wires 12a are made of copper or copper alloy. The bare metal wires 12a may also be plated with silver, tin, or the like. To improve the conductivity and mechanical strength of the shielding layer 12, it is preferable to use bare metal wires 12a made of silver-plated copper alloy.

[0048] The outer layer 13 is provided to cover the periphery of the shielding layer 12. The outer layer 13 is preferably constructed, for example, by winding a resin tape. More specifically, for example, the outer layer 13 can be constructed as a two-layer structure: a first layer consisting of a non-adhesive resin tape wound in a spiral shape with a partial overlap in the width direction; and a second layer consisting of an adhesive resin tape having a heat-melt adhesive layer on one side of the resin layer, wound in a spiral shape with the adhesive layer of the resin tape as the inner side, with a partial overlap in the width direction. Then, by heating, the adhesive layer is melted and bonded to the non-adhesive resin tape of the first layer, thus forming the outer layer 13. As the resin constituting the resin tape, PET (polyethylene terephthalate), PI (polyimide), PEEK (polyetheretherketone), PEI (polyetherimide), etc., can be used.

[0049] Here, the case where cable 10 is a coaxial cable has been described, but the specific structure of cable 10 is not limited to the structure shown in the figure. For example, it can also be an insulated wire with an insulator 11 surrounding the compressed stranded conductor 1.

[0050] In addition, such as Figure 3 As shown in (a) and (b), cable 10 can also be a multi-core cable 10a using compressed stranded conductor 1 as the core wire. Figure 3 In the example, the multi-core cable 10a includes cable cores 15, a binding strap 16 wound around the cable cores 15, a general shielding layer 17 covering the binding strap 16, and a sheath 18 covering the general shielding layer 17. The cable cores 15 are made of 12 strands, and the 16 strands are wound around the cable cores. Figure 2 The cable 10 (coaxial cable) shown is twisted together to form a sub-stranded wire 14, which is formed by twisting these 12 sub-stranded wires 14 together.

[0051] The cable core 15 is constructed by twisting three sub-strands 14 together and then twisting nine more sub-strands 14 around it. The twisting direction in each layer of the cable core 15 is the same. A binding tape 16 is spirally wound around the cable core 15, overlapping a portion of its width. The overall shielding layer 17 is a braided shield composed of multiple bare wires. The sheath 18 can be formed by tube extrusion to prevent the resin constituting the sheath 18 from entering between the bare wires of the overall shielding layer 17.

[0052] (Connection structure 100)

[0053] Figure 4 (a) is a top view showing the connection structure 100 of this embodiment. Figure 4 (b) is a photograph showing a cross-section of the connection between the compressed stranded conductor 1 and the electrode 102.

[0054] like Figure 4 As shown in (a), the connection structure 100 is constructed by connecting the compressed stranded wire conductor 1 to the electrode 102 formed on the substrate 101 using solder 104. In the example shown, multiple strands are depicted... Figure 2 The cable 10 (coaxial cable) is connected to the substrate 101. Multiple electrodes 102 (signal electrodes) corresponding to the compressed stranded conductors 1 of each cable 10 and a ground electrode 103 shared by each cable 10 are formed on the substrate 101. The multiple electrodes 102 are arranged perpendicularly to the extension direction of the cable 10, and the ground electrode 103 is formed closer to the extension side of the cable 10 than the multiple electrodes 102.

[0055] At the end of cable 10, shielding layer 12 protrudes from the end of outer jacket 13, insulator 11 protrudes from the end of shielding layer 12, and compressed stranded conductor 1 protrudes from the end of insulator 11. Furthermore, the shielding layer 12 of each cable 10 is connected to a common grounding electrode 103 via solder 105, and the compressed stranded conductor 1 of each cable 10 is connected to its corresponding electrode 102 via solder 104.

[0056] like Figure 4 As shown in (b), the compressed stranded conductor 1 is not easily unraveled during processing and its cross-sectional shape can be easily maintained. That is, the compressed stranded conductor 1 maintains a state where the central portion 21 and multiple peripheral portions 22, as well as adjacent peripheral portions 22, are tightly packed with the second metal portion 3 sandwiched between them. Therefore, the solder 104 does not enter the interior of the compressed stranded conductor 1, and brazing can be performed uniformly by having the solder 104 surround the outer peripheral surface of the compressed stranded conductor 1. Therefore, voids (bubbles) are less likely to form in the solder 104, and the compressed stranded conductor 1 is less likely to detach from the solder 104, resulting in high connection reliability. Furthermore, since the cross-sectional shape of the compressed stranded conductor 1 is less prone to irregularity, the surface of the solder 104 can be easily formed into a regular arc shape.

[0057] In contrast, in the case of a stranded conductor consisting of only 7 bare metal wires twisted concentrically, for example... Figure 5As shown, solder 104 can penetrate between bare metal wires 4, causing the arrangement of the bare metal wires 4 to become disordered and prone to voids 106. Consequently, the fixation of the bare metal wires 4 becomes unsatisfactory. If a force is applied to stretch the conductor for some reason, stress may concentrate on only a portion of the bare metal wires 4, leading to wire breakage and reduced connection reliability. Furthermore, the disorder of the bare metal wires 4 also causes the surface of the solder 104 to become disordered, making it difficult for the solder 104 to form a regular arc shape, resulting in a deteriorated appearance.

[0058] Furthermore, in the connection structure 100 of this embodiment, since the twisting of the compressed stranded conductor 1 is difficult to untangle, the area required for soldering can be reduced (to the same extent as in the case of using a single conductor). As a result, multiple compressed stranded conductors 1 can be connected in parallel with a narrow pitch, which helps to increase the density of wiring and to miniaturize devices using the substrate 101.

[0059] (The role and effects of the implementation method)

[0060] As described above, the outer diameter of the compressed stranded conductor 1 in this embodiment is 0.1 mm or less and includes a first metal portion 2 and a second metal portion 3. The first metal portion 2 has a central portion 21 and a plurality of peripheral portions 22 spirally twisted around the central portion 21. The central portion 21 and the plurality of peripheral portions 22 are interlocked to form a circular cross-section. The second metal portion 3 is made of a metal with a higher conductivity than the first metal portion 2 and covers each of the central portion 21 and the plurality of peripheral portions 22. The central portion 21 and the plurality of peripheral portions 22, as well as adjacent peripheral portions 22, are sandwiched between each other and in close contact with the second metal portion 3.

[0061] This configuration results in a striped pattern of highly conductive second metal portions 3 when viewed in cross-section, thereby improving the overall conductivity of the compressed stranded conductor 1 and enhancing its electrical characteristics. Furthermore, by using bare metal wire 4 covered by the second metal portion 3 with the first metal portion 2, the second metal portion 3 functions as a protective layer, enabling the compressed stranded conductor 1 to achieve a small diameter while minimizing breakage during manufacturing. It should be noted that while manufacturing with low tension is considered to prevent breakage, this makes tension adjustment difficult, increases manufacturing complexity, and makes it difficult to obtain the desired electrical characteristics. According to this embodiment, even with relatively high tension during manufacturing, breakage is less likely, thus enabling the production of a compressed stranded conductor 1 that is easy to manufacture and has high productivity.

[0062] (Summary of Implementation Methods)

[0063] Next, the technical ideas learned from the embodiments described above will be described by reference to the accompanying reference numerals and the like. However, the symbols and the like described below do not limit the constituent elements in the claims to the components specifically shown in the embodiments.

[0064] [1] A compressed stranded wire conductor 1, having an outer diameter of 0.1 mm or less and comprising:

[0065] The first metal part 2 has a central part 21 and a plurality of peripheral parts 22 spirally interlocked around the central part 21, the central part 21 and the plurality of peripheral parts 22 fitting together to form a circular cross-section.

[0066] The second metal part 3 is made of a metal with a higher conductivity than the first metal part 2, and covers the central part 21 and each of the plurality of peripheral parts 22;

[0067] The central portion 21 and the plurality of surrounding portions 22, as well as adjacent surrounding portions 22, are in close contact with each other, sandwiching the second metal portion 3.

[0068] [2] According to the compressed stranded conductor 1 described in [1], in a cross section perpendicular to the length direction, the cross-sectional area occupied by the second metal part 3 accounts for more than 10% of the total cross-sectional area.

[0069] [3] According to the compressed stranded conductor 1 of [1], in a cross section perpendicular to the length direction, the cross-sectional area occupied by the second metal part 3 is 15% or less relative to the total cross-sectional area.

[0070] [4] According to the compressed stranded conductor 1 of [1], in a cross section perpendicular to the length direction, the cross-sectional area of ​​the central portion 21 is less than the average of the cross-sectional areas of the plurality of peripheral portions 22.

[0071] [5] According to the compressed stranded conductor 1 of [1], wherein in the second metal portion 3, the thickness of at least a plurality of peripheral portions 22 between each other is greater than the thickness at the outer peripheral surface of the conductor.

[0072] [6] According to the compressed stranded conductor 1 of [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.

[0073] [7] According to the compressed stranded conductor 1 of [1], the first metal part 2 is made of copper alloy and the second metal part 3 is made of copper.

[0074] [8] The outer diameter of the compressed stranded conductor 1 according to [1] is less than 0.061 mm.

[0075] [9] According to the compressed stranded conductor 1 described in [1], in a cross section perpendicular to the length direction, the area of ​​the gap 5 is less than 1.5% of the area of ​​the conductor's outer circle.

[0076]

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

[0077]

[11] A connection structure 100 is a connection structure formed by connecting a conductor to an electrode 102 formed on a substrate 101 by solder 104, wherein the conductor is a compressed stranded wire conductor 1 with an outer diameter of 0.1 mm or less, and comprises:

[0078] The first metal part 2 has a central part 21 and a plurality of peripheral parts 22 spirally interlocked around the central part 21, wherein the central part 21 and the plurality of peripheral parts 22 interlock to form a circular cross-section.

[0079] The second metal part 3 is made of a metal with a higher conductivity than the first metal part 2, and covers the central part 21 and each of the plurality of peripheral parts 22;

[0080] The central portion 21 and the plurality of surrounding portions 22, as well as adjacent surrounding portions 22, are in close contact with each other, sandwiching the second metal portion 3.

[0081] The solder 104 did not enter the interior of the compressed stranded conductor 1.

[0082] (Postscript)

[0083] The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that the combinations of features described in the embodiments are not necessarily all necessary for the method to solve the problems of the invention. In addition, the present invention can be implemented with appropriate modifications without departing from its spirit.

Claims

1. A compressed stranded wire conductor having an outer diameter of 0.1 mm or less and comprising: A first metal portion having a central portion and a plurality of peripheral portions spirally interlocked around the central portion, the central portion and the plurality of peripheral portions fitting together to form a circular cross-section overall. The second metal portion, made of a metal with a higher conductivity than the first metal portion, covers the central portion and each of the plurality of surrounding portions; The central portion and the plurality of surrounding portions, as well as adjacent surrounding portions, are in close contact with the second metal portion sandwiched between them.

2. The compressed stranded conductor according to claim 1, wherein, In a cross-section perpendicular to the length direction, the cross-sectional area occupied by the second metal part accounts for more than 10% of the total cross-sectional area.

3. The compressed stranded conductor according to claim 1, wherein, In a cross-section perpendicular to the length direction, the cross-sectional area occupied by the second metal part accounts for less than 15% of the total cross-sectional area.

4. The compressed stranded conductor according to claim 1, wherein, In a cross-section perpendicular to the length direction, the cross-sectional area of ​​the central portion is less than the average of the cross-sectional areas of the plurality of surrounding portions.

5. The compressed stranded conductor according to claim 1, wherein, In the second metal portion, the thickness of at least a plurality of peripheral portions relative to each other is greater than the thickness at the outer peripheral surface of the conductor.

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

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

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

9. The compressed stranded conductor according to claim 1, wherein, In a cross-section perpendicular to the length direction, the area of ​​the void is less than 1.5% of the area of ​​the conductor's circumcircle.

10. A cable comprising at least one compressed stranded conductor as claimed in any one of claims 1 to 9 and a sheath surrounding said compressed stranded conductor.

11. A connection structure formed by connecting a conductor to an electrode formed on a substrate using solder, wherein the conductor is a compressed stranded wire conductor with an outer diameter of 0.1 mm or less, and comprises: A first metal portion having a central portion and a plurality of peripheral portions spirally interlocked around the central portion, the central portion and the plurality of peripheral portions fitting together to form a circular cross-section overall. The second metal portion, made of a metal with a higher conductivity than the first metal portion, covers the central portion and each of the plurality of surrounding portions; The central portion and the plurality of surrounding portions, as well as adjacent surrounding portions, are in close contact with the second metal portion by sandwiching each other. The solder did not penetrate the interior of the compressed stranded conductor.

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