Electric wires and cables

Abstract

To provide an electric wire and a cable which are capable of inhibiting electric corrosion.SOLUTION: An electric wire 1 includes a conductor 2 and an insulator 3 disposed so as to cover a periphery of the conductor 2. The conductor 2 includes: a first conductor part 2a using a first wire 211 composed of aluminum or aluminum alloy; and a second conductor part 2b using a second wire 221 composed of copper or copper alloy. The electric wire includes an electric corrosion inhibiting member 4 interposed between the first conductor part 2a and the second conductor part 2b so as to inhibit electrochemical corrosion between the first conductor part 2a and the second conductor part 2b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to electric wires and cables. [Background technology]

[0002] Conventionally, insulated wires comprising a conductor and an insulator covering the conductor have been widely used. Patent Document 1 proposes a wire using a metal-coated wire as the conductor, comprising a core made of aluminum or an aluminum alloy and a metal layer made of copper or a copper alloy covering the outer circumference of the core. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2018-56101 [Overview of the project] [Problems that the invention aims to solve]

[0004] When using both strands made of aluminum or aluminum alloy and strands made of copper or copper alloy as conductors in electric wires and cables, electrochemical corrosion (hereinafter referred to as galvanic corrosion) may occur, for example in humid environments, and countermeasures are desirable.

[0005] Therefore, the present invention aims to provide electric wires and cables capable of suppressing electrolytic corrosion. [Means for solving the problem]

[0006] The present invention aims to solve the above problems and provides an electric wire comprising a conductor and an insulator provided to cover the conductor, wherein the conductor has a first conductor portion using first strands made of aluminum or an aluminum alloy and a second conductor portion using second strands made of copper or a copper alloy, and an electrochemical corrosion suppression member provided interposed between the first conductor portion and the second conductor portion to suppress electrochemical corrosion between the first conductor portion and the second conductor portion.

[0007] Furthermore, the present invention aims to solve the above problems by providing a cable comprising a cable core containing a plurality of electric wires and a sheath provided to cover the periphery of the cable core collectively. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide electric wires and cables that can suppress electrolytic corrosion. [Brief explanation of the drawing]

[0009] [Figure 1] This figure shows an electric wire according to one embodiment of the present invention, where (a) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction, and (b) is a diagram illustrating the overlapping winding of the electrolytic corrosion suppression member. [Figure 2] This is an enlarged view of a portion of Figure 1(a). [Figure 3] (a) is a cross-sectional view showing a corrosion-inhibiting member, and (b) to (d) are diagrams showing modified versions thereof. [Figure 4] (a) and (b) are cross-sectional views showing modified examples of the conductor. [Figure 5] (a) and (b) are cross-sectional views showing modified examples of the conductor. [Figure 6] 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. [Modes for carrying out the invention]

[0010] [Embodiment] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0011] Figure 1 shows an electric wire 1 according to this embodiment, where (a) is a cross-sectional view showing a cross-section perpendicular to the longitudinal direction, and (b) is a diagram illustrating the overlapping winding of the electrolytic corrosion suppression member 4. Note that Figure 1(b) schematically shows a cross-section parallel to the longitudinal direction of the electric wire 1.

[0012] As shown in Figures 1(a) and 1(b), the electric wire 1 comprises a conductor 2 and an insulator 3 provided to surround the conductor 2. When the electric wire 1 is used, for example, as a power supply wire, its conductor cross-sectional area is 0.75 mm². 2 (0.75SQ) or more 350mm 2 (350SQ) or less. The electric wire 1 according to this embodiment is particularly effective in reducing the amount of copper used when its outer diameter (outer diameter of the insulator 3) is relatively large, such as 10 mm or more, and its conductor cross-sectional area is 60 mm². 2 (60SQ) or larger, more preferably 80mm 2 (80SQ) or larger. In this embodiment, the conductor cross-sectional area is approximately 100 mm². 2 (100SQ) was used. Note that the wire 1 is not limited to being used as a power supply wire, but may also be used as a signal wire for signal transmission, for example. When used as a signal wire, the outer diameter of the wire 1 is 0.8 mm or more and 2.0 mm or less, and the conductor cross-sectional area in this case is 0.10 mm². 2 (0.10SQ) or larger, 1mm 2 (1SQ) or less.

[0013] (Conductor 2) The conductor 2 has a first conductor portion 2a located at the center of the electric wire 1 (the center of the cross-section perpendicular to the longitudinal direction), and a second conductor portion 2b provided to surround the first conductor portion 2a.

[0014] The first conductor part 2a is composed of a plurality of first sub-stranded wires 21 formed by stranding first base wires 211 made of aluminum or an aluminum alloy. Examples of the aluminum alloy used as the first base wire 211 include an Al-Zr alloy, an Al-Ni-Zr alloy, an Al-Co-Zr alloy, an Al-Fe-Zr alloy, and the like. Note that the first base wire 211 may contain impurities inevitable in production. The tensile strength of the first base wire 211 is 200 MPa or less, and the elongation at break is 5% or more and 17% or less. The tensile strength and elongation at break of the first base wire 211 are smaller than those of the second base wire 221 described later. Here, a first base wire 211 made of aluminum with an outer diameter of 0.45 mm is used. The outer diameter of the first base wire 211 is, for example, 0.10 mm or more and 0.50 mm or less. The outer diameter of the first base wire 211 is preferably the same as or smaller than the outer diameter of the second base wire 221. For example, the outer diameter of the first base wire 211 is preferably 90% or more and 100% or less of the outer diameter of the second base wire 221. Thereby, the effect of reducing the outer diameter of the conductor 2 while reducing the amount of copper used in the conductor 2 can be easily obtained.

[0015] Each first sub-stranded wire 21 constituting the first conductor part 2a is formed by collectively stranding a plurality of first base wires 211. That is, each first sub-stranded wire 21 is composed of a collectively stranded wire in which a plurality of first base wires 211 are collectively stranded. By collectively stranding a plurality of first base wires 211 to form the first sub-stranded wire 21, the first base wires 211 can easily move within the first sub-stranded wire 21, and the shape of the first sub-stranded wire 21 can easily change due to an external force. Therefore, it is possible to reduce the gaps between the first sub-stranded wires 21 and between the first sub-stranded wire 21 and the second sub-stranded wire 22 (described later) by the force when twisting the second sub-stranded wire 22 described later, and reduce the outer diameter of the conductor 2. In the present embodiment, the first sub-stranded wire 21 is formed of a collectively stranded wire in which 16 first base wires 211 are collectively stranded. Note that the number of first base wires 211 constituting the first sub-stranded wire 21 is not limited to 16. That is, the number of first base wires 211 constituting the first sub-stranded wire 21 may be less than 16 or more than 16.

[0016] Also, in the present embodiment shown in FIG. 1, the number of the first sub-strands 21 constituting the first conductor portion 2a is 19, but it is not limited thereto. The number of the first sub-strands 21 constituting the first conductor portion 2a can be appropriately changed within the range where the ratio of the number of the first sub-strands 21 to the number of the second sub-strands 22 (the number of the first sub-strands 21 / the number of the second sub-strands 22) described later is 40 / 60 or more and 60 / 40 or less. Further, the outer diameter of the first sub-strand 21 is preferably the same as or smaller than the outer diameter of the second sub-strand 22 described later. Thereby, the first sub-strand 21 made of aluminum or an aluminum alloy, which is more easily deformed than the second sub-strand 22 made of copper or a copper alloy, is more easily deformed by the force received from the second sub-strand 22 side. Therefore, it is easy to obtain the effect of reducing the outer diameter of the conductor 2 while reducing the amount of copper used for the conductor 2.

[0017] The first conductor portion 2a is formed by concentrically twisting a plurality of first sub-strands 21. In the present embodiment, one first sub-strand 21 is provided at the center of the electric wire 1, six first sub-strands 21 are provided around it, and twelve first sub-strands 21 are further provided around it, and a total of 19 first sub-strands 21 are concentrically twisted to form the first conductor portion 2a. The concentric twisting configuration of the first conductor portion 2a is not limited thereto. For example, the first conductor portion 2a may have a configuration in which one first sub-strand 21 is provided at the center and six first sub-strands 21 are concentrically twisted around it. Also, the first conductor portion 2a may have a configuration in which one first sub-strand 21 is provided at the center, six first sub-strands 21 are provided around it, twelve first sub-strands 21 are provided around it, and a plurality of first sub-strands 21 are further arranged around it and concentrically twisted. By forming the first conductor portion 2a by concentric twisting, it becomes possible to increase the conductor cross-sectional area while reducing the outer diameter, making the entire conductor 2 have a small diameter, which leads to a reduction in the overall diameter of the electric wire 1. The number of the first sub-strands 21 used for the first conductor portion 2a is not limited to 19. For example, the twelve first sub-strands 21 in the outermost layer may be omitted to make it seven, or eighteen first sub-strands 21 may be further added to the outermost layer to make it 37.

[0018] The second conductor section 2b is constructed by twisting together multiple second strands 22, each made of copper or a copper alloy, and these strands 22 are twisted around the first conductor section 2a. The second strands 221 may be plated with Zn (e.g., amorphous Zn), Ni, Sn, etc. on their surface. The tensile strength of the second strands 221 is 220 MPa or more, and the elongation at break is 10% or more. The tensile strength and elongation at break of the second strands 221 are greater than those of the first strands 211. Here, the second strands 221 are made of Sn-plated soft copper wire with an outer diameter of 0.45 mm, the same outer diameter as the first strands 211. The outer diameter of the second strands 221 is, for example, 0.10 mm or more and 0.50 mm or less. It is preferable that the outer diameter of the second strands 221 is the same as or larger than the outer diameter of the first strands 211. This makes it easier to reduce the amount of copper used in conductor 2 while also reducing the outer diameter of conductor 2.

[0019] Each second stranded wire 22 constituting the second conductor section 2b is formed by twisting together multiple second strands 221. By twisting together multiple second strands 221 to form the second stranded wire 22, the second strands 221 become more mobile within the second stranded wire 22, making it easier for the shape of the second stranded wire 22 to change due to external forces. Therefore, the force applied when twisting the second stranded wires 22 together can reduce the gaps between the second stranded wires 22 and between the first stranded wire 21 and the second stranded wire 22, thereby reducing the outer diameter of the conductor 2. In this embodiment, similar to the first stranded wire 21 described above, 16 second strands 221 were twisted together to form the second stranded wire 22. However, the number of second strands 221 constituting the second stranded wire 22 is not limited to 16. The number of second strands 221 constituting the second stranded wire 22 may be less than 16 or more than 16.

[0020] Furthermore, in this embodiment shown in Figure 1, the number of second strands 22 constituting the second conductor section 2b is set to 18, but this is not limited to this. The number of second strands 22 constituting the second conductor section 2b can be appropriately changed within the range where the ratio of the number of first strands 21 to the number of second strands 22 (number of first strands 21 / number of second strands 22) is between 40 / 60 and 60 / 40. In addition, it is preferable that the outer diameter of the second strands 22 be the same as or larger than the outer diameter of the first strands 21. This makes the first strands 21, which are made of aluminum or an aluminum alloy and are more easily deformed than the second strands 22 made of copper or a copper alloy, more easily deformed by the force received from the second strands 22 side (that is, the first strands 21 can be easily deformed by the second strands 22, which are harder than the first strands 21). Therefore, it becomes easier to achieve the effect of reducing the outer diameter of conductor 2 while reducing the amount of copper used in conductor 2.

[0021] In this embodiment, the first strand 211 and the second strand 221 are made of the same outer diameter, and the number of first strands 211 constituting the first sub-strand 21 is the same as the number of second strands 221 constituting the second sub-strand 22. As a result, the outer diameters of the first sub-strand 21 and the second sub-strand 22 are almost the same. This makes it less likely for gaps to form between the sub-strands 21 and 22 due to concentric twisting.

[0022] The second conductor section 2b is constructed by twisting 18 second strands 22 around the first conductor section 2a, thereby ensuring that the entire conductor 2 is concentrically twisted. In other words, the conductor 2 is constructed by concentrically twisting multiple (19 in this case) first strands 21 and multiple (18 in this case) second strands 22. This makes it possible to increase the conductor cross-sectional area while reducing the outer diameter, resulting in a smaller diameter for the entire conductor 2 and leading to a smaller diameter for the entire electric wire 1.

[0023] The ratio of the number of first stranded wires 21 to the number of second stranded wires 22 used in conductor 2 (number of first stranded wires 21 / number of second stranded wires 22) should be between 40 / 60 and 60 / 40. Furthermore, the ratio of the cross-sectional area of ​​the first conductor section 2a (= sum of the cross-sectional areas of each first stranded wire 21) to the cross-sectional area of ​​the second conductor section 2b (= sum of the cross-sectional areas of each second stranded wire 22) should be between 40 / 60 and 60 / 40. This suppresses the increase in the resistance of conductor 2 and reduces heat generation, while also reducing the amount of copper used, resulting in a smaller diameter wire 1, and enabling the creation of a lightweight and easily bendable wire 1. For example, to reduce the amount of copper used in conductor 2 while making the wire 1 smaller in diameter, and to increase the conductivity of conductor 2 by reducing its resistance (=conductor resistance), the ratio of the cross-sectional area of ​​the first conductor section 2a to the cross-sectional area of ​​the second conductor section 2b should be 40 / 50 or more and 50 / 50 or less (more preferably 40 / 50 or more and 45 / 55 or less). On the other hand, to reduce the amount of copper used in conductor 2 while making the wire 1 smaller in diameter, and to make the wire 1 lighter and easier to bend, the ratio of the cross-sectional area of ​​the first conductor section 2a to the cross-sectional area of ​​the second conductor section 2b should be 50 / 50 or more and 60 / 40 or less (more preferably 55 / 45 or more and 60 / 40 or less). Furthermore, the same effect as when changing the ratio of the cross-sectional areas described above can be obtained by changing the ratio of the first stranded wires 21 to the number of second stranded wires 22 used in conductor 2 within the range of 40 / 60 or more and 60 / 40 or less.

[0024] By the way, when forming the conductor 2, a second stranded wire 22 made of copper or a copper alloy is twisted around a first conductor portion 2a made of aluminum or an aluminum alloy to form a second conductor portion 2b. At this time, since the first conductor portion 2a made of aluminum or an aluminum alloy is relatively soft and easy to deform, when the second stranded wire 22 made of copper or a copper alloy, which has higher rigidity compared to the first stranded wire 21, is twisted around the first conductor portion 2a, the first conductor portion 2a is pushed inward (towards the cable center side) (compressed) by the force applied during the twisting. As a result, the first stranded wire 21 constituting the first conductor portion 2a is crushed, the gaps inside the first conductor portion 2a become smaller, and the outer diameter of the first conductor portion 2a becomes smaller (that is, the outer diameter of the first conductor portion 2a is smaller compared to the state before twisting the second stranded wire 22). Thereby, the outer diameter of the entire conductor 2 can be reduced, and the entire diameter of the electric wire 1 can be made smaller.

[0025] That is, by forming the first conductor portion 2a of aluminum or an aluminum alloy, it is possible to reduce the outer diameter of the conductor 2 while maintaining the conductor cross-sectional area, and also to reduce the outer diameter of the entire electric wire 1. For example, in this embodiment, the conductor cross-sectional area is 100 mm 2 (100 SQ), but it is possible to reduce the outer diameter of the conductor 2 to the outer diameter equivalent to 80 mm 2 (80 SQ) in a conventional conductor using only copper strands.

[0026] Also, by forming the first conductor portion​​​Incidentally, the first strand 211, which is made of aluminum or an aluminum alloy, is susceptible to damage and may easily break if damaged. However, by providing a second conductor part 2b made of copper or a copper alloy so as to surround the first conductor part 2a, the first strand 211 constituting the first conductor part 2a is protected from damage by the second conductor part 2b, and the breakage of the first strand 211 can be suppressed.

[0028] Furthermore, by constructing the second conductor section 2b, where the load is concentrated during bending, from relatively high-strength copper or a copper alloy, the bending resistance can be improved. Also, by constructing the second conductor section 2b from copper or a copper alloy, it is possible to suppress the resistance value of conductor 2 from becoming too high, and it becomes possible to maintain electrical characteristics that are almost equivalent to those of conventional electric wires using conductors made only of copper or a copper alloy.

[0029] Furthermore, by constructing the second conductor section 2b from copper or a copper alloy, connection to terminals of conductor 2 becomes easier compared to the case where the entire conductor 2 is constructed from aluminum or an aluminum alloy. For example, when the entire conductor 2 is constructed from aluminum or an aluminum alloy, it was necessary to use terminals with a special structure to maintain the strength of the connection. However, by constructing the second conductor section 2b from copper or a copper alloy, conventionally used terminals (for example, terminals that are crimped and fixed to the end of conductor 2) can be used, and conventional soldering connections are also possible, thus improving versatility.

[0030] Furthermore, conventional electric wires that use only copper or copper alloy as conductors sometimes sag under their own weight when wired in a floating position. However, in the electric wire 1 according to this embodiment, the first conductor section 2a is made lighter by using aluminum or an aluminum alloy, and the rigidity of the electric wire 1 is ensured by using copper or a copper alloy for the second conductor section 2b. Therefore, even when the electric wire 1 is wired in a floating position (for example, bent into a U-shape), it is possible to suppress it from sagging under its own weight.

[0031] (Electrolytic corrosion suppression member 4) As described above, in this embodiment, the first conductor portion 2a is made of aluminum or an aluminum alloy, and the second conductor portion 2b is made of copper or a copper alloy. Because aluminum and copper have a large standard electrode potential difference, electrochemical corrosion (hereinafter referred to as galvanic corrosion) may occur depending on the environment in which it is used, such as in a humid environment. Therefore, in this embodiment, a galvanic corrosion suppression member 4 is provided between the first conductor portion 2a and the second conductor portion 2b to suppress galvanic corrosion between the first conductor portion 2a and the second conductor portion 2b.

[0032] In this embodiment, the electrolytic corrosion suppression member 4 consists of one or more conductive tape members spirally wound around the first conductor portion 2a. In this embodiment, the case in which the electrolytic corrosion suppression member 4 consists of one tape member 41 will be described. Details of the tape member 41 will be described later. The second conductor portion 2b is formed by spirally twisting a plurality of second stranded wires 22 around this electrolytic corrosion suppression member 4.

[0033] As shown in Figure 1(b), the tape member 41, which is the electrolytic corrosion suppression member 4, is wrapped around the first conductor portion 2a such that a portion of it overlaps (wraps) in the width direction. The wrap length (overlap width) when wrapping is preferably between 1 / 3 and 1 / 2 of the width of the tape member 41. For example, the width of the tape member 41 is between 10 mm and 50 mm. By having a wrap length of 1 / 3 or more of the width of the tape member, gaps between the tape members are suppressed even when the electric wire 1 is bent. Furthermore, by having a wrap length of 1 / 2 or less of the width of the tape member, it is suppressed that three or more tape members overlap, which suppresses the occurrence of gaps in the wrapped portion and makes it possible to stabilize the electrical characteristics of the conductor 2, as well as suppressing an increase in the diameter of the conductor 2.

[0034] In this embodiment, the twisting direction of the first conductor section 2a and the winding direction of the electrolytic corrosion suppression member 4 are in opposite directions. This makes it possible to firmly tighten the twist of the first conductor section 2a with the electrolytic corrosion suppression member 4 so that the twist does not loosen, thereby suppressing the increase in contact resistance due to loosening of the twist and the deterioration of the electrical characteristics of the conductor 2 caused by it. The twisting direction of the first conductor section 2a is the direction in which the first stranded wire 21 rotates from one end to the other when viewed from one end of the electric wire 1. The winding direction of the electrolytic corrosion suppression member 4 is the direction in which the tape member 41 rotates from one end to the other when viewed from one end of the electric wire 1.

[0035] Furthermore, in this embodiment, the winding direction of the galvanic corrosion suppression member 4 and the twisting direction of the second conductor section 2a are in the same direction. In other words, the twisting direction of the first conductor section 2a and the twisting direction of the second conductor section 2a are in opposite directions. As a result, by twisting the second conductor section 2a together, the first conductor section 2a is tightened further, suppressing loosening of the twist, and the first conductor section 2a is compressed inward, making the overall outer diameter of the conductor 2 smaller. The twisting direction of the second conductor section 2b is the direction in which the second stranded wire 22 rotates from one end to the other when viewed from one end of the electric wire 1.

[0036] Furthermore, by making the winding direction of the galvanic corrosion suppression member 4 and the twisting direction of the second conductor portion 2a the same, as shown in Figure 2, it becomes possible to push the galvanic corrosion suppression member 4 inward, thereby reducing the gap 5 that forms around the galvanic corrosion suppression member 4. In other words, the galvanic corrosion suppression member 4 is pushed from the second conductor portion 2b side to the first conductor portion 2a side, and the galvanic corrosion suppression member 4 fits between adjacent first stranded wires 21, reducing the gap 5 around the galvanic corrosion suppression member 4. As a result, the contact area between the first conductor portion 2a and the second conductor portion 2b and the galvanic corrosion suppression member 4 can be increased, thus reducing the contact resistance between the first conductor portion 2a and the second conductor portion 2b and the galvanic corrosion suppression member 4, and further improving the electrical characteristics of the conductor 2. In addition, when connecting terminals to the ends of the conductor 2 by crimping, the twist is less likely to loosen, so less air gap is likely to form around the galvanic corrosion suppression member 4, and the resistance at the connection part between the conductor 2 and the terminal can be reduced.

[0037] As shown in Figure 3(a), the tape member 41 used as the electrolytic corrosion suppression member 4 in this embodiment integrally comprises a first metal layer 411 made of aluminum or an aluminum alloy formed on one side, a second metal layer 412 made of copper or a copper alloy formed on the other side, a conductive adhesive layer 413 provided between the first metal layer 411 and the second metal layer 412 to bond them together and provide electrical conductivity, and a plating layer 414 made of tin formed on the surface of the second metal layer 412 by electroplating. The tape member 41 is wrapped around the first conductor portion 2a with the first metal layer 411 on the first conductor portion 2a side and the second metal layer 412 on the second conductor portion 2b side (see Figure 1(b)).

[0038] The thickness of the first metal layer 411, made of aluminum or an aluminum alloy, and the thickness of the second metal layer 412, made of copper or a copper alloy, should be between 7 μm and 25 μm. By setting the thickness of the first metal layer 411 and the second metal layer 412 to 7 μm or more, it is possible to suppress the breakage of the tape member 41, even when terminals are fixed at the ends by crimping. Furthermore, by setting the thickness of the first metal layer 411 and the second metal layer 412 to 25 μm or less, it is possible to suppress the tape member 41 from becoming too rigid, making it difficult to bend the electric wire 1, or causing the conductor 2 to become too large in diameter. Furthermore, if the thickness of the first metal layer 411 and the second metal layer 412 is greater than 25 μm, the tape member 41 becomes harder, which may cause the edge portion of the spirally wound tape member 41 (the step created in the wrapped portion) to rub against the conductor portions 2a and 2b, potentially damaging them. However, as in this embodiment, by making the thickness of the first metal layer 411 and the second metal layer 412 less than 25 μm, it is possible to suppress such problems.

[0039] As the conductive adhesive layer 413, a hot-melt adhesive in which conductive particles are dispersed can be used. As the hot-melt adhesive, for example, an acrylic adhesive can be used. As the conductive particles, for example, Ni particles can be used. The thickness of the conductive adhesive layer 413 should be determined considering the particle size of the conductive particles used, and should be between 1 and 2 times the particle size of the conductive particles. In this embodiment, Ni particles with a particle size of about 6 μm were used as the conductive particles, in which case the thickness of the conductive adhesive layer 413 should be between 6 μm and 12 μm.

[0040] As shown in Figure 1(b), the tape member 41 is wound so that a portion of it overlaps in the width direction, resulting in a contact area between the first metal layer 411 made of aluminum or an aluminum alloy and the second metal layer 412 made of copper or a copper alloy. This contact area may be susceptible to galvanic corrosion. Therefore, to suppress galvanic corrosion at the contact area between the first metal layer 411 and the second metal layer 412, a tin plating layer 414 is provided on the surface of the second metal layer 412.

[0041] [Table 1]

[0042] As shown in Table 1, the standard electrode potential difference between aluminum (Al) and copper (Cu) is large, at 2V or more, and even at the natural potential close to the actual operating environment (natural potential in a 0.1M NaCl aqueous solution), the potential difference is 0.5V or more, making galvanic corrosion likely. In contrast, the standard electrode potential of tin (Sn) is closer to that of aluminum than that of copper, and at the natural potential close to the actual operating environment (natural potential in a 0.1M NaCl aqueous solution), it is approximately midway between the potentials of aluminum and copper. Therefore, by interposing tin between copper and aluminum, it is possible to reduce the potential difference between adjacent metals and suppress galvanic corrosion. Thus, by providing a plating layer 414 made of tin on the surface of the second metal layer 412, it is possible to suppress galvanic corrosion in the overlapping portion.

[0043] Furthermore, it is undesirable to use a plating layer 414 formed by hot-dip plating; it is preferable to use one formed by electroplating. This is because, in hot-dip plating, some of the copper melts into the molten tin, resulting in copper being included in the plating. Moreover, in hot-dip plating, a small amount of copper is sometimes intentionally added to the molten tin to suppress copper leaching, which can result in a large amount of copper being included in the plating. When copper is included in the plating, galvanic corrosion is more likely to occur due to the potential difference between the copper and the aluminum. In addition, compared to electroplating, hot-dip plating tends to result in uneven plating thickness, making it more prone to problems such as peeling in areas where the plating is thin. Therefore, it is desirable to form the plating layer 414 by electroplating, which does not include copper in the plating during the manufacturing process and tends to produce a uniform thickness.

[0044] In this embodiment, tin-plated soft copper wire is used as the second strand 221. For the tin plating used on this second strand 221, it is desirable to use hot-dip plating, which has low manufacturing costs and is easy to mass-produce. As mentioned above, when tin plating is hot-dip plating, the plating layer contains a large amount of copper, so galvanic corrosion is likely to occur when it comes into direct contact with aluminum or aluminum alloys. Therefore, even when using a tin-plated second strand, it is necessary to provide a galvanic corrosion suppression member 4 to suppress galvanic corrosion between the first and second conductor parts 2a and 2b.

[0045] (Modified example of the electrolytic corrosion suppression member 4) In this embodiment, a first metal layer 411 made of aluminum or an aluminum alloy and a second metal layer 412 made of copper or a copper alloy are joined by a conductive adhesive layer 413. However, the invention is not limited to this, and as shown in Figure 3(b), a tape member 41a made of a clad material in which the first metal layer 411 made of aluminum or an aluminum alloy and the second metal layer 412 made of copper or a copper alloy are directly joined may be used as the electrolytic corrosion suppression member 4.

[0046] Furthermore, as shown in Figure 3(c), a tape member consisting of a copper tape 42 in which tin plating layers 422 and 423 are formed on both sides of a metal layer 421 made of copper or a copper alloy by electroplating may be used as the galvanic corrosion suppression member 4. In this case, the tin plating layer 422 (or 423) is interposed between the first conductor portion 2a made of aluminum or an aluminum alloy and the metal layer 421 made of copper or a copper alloy, thereby suppressing galvanic corrosion. Note that the plating layer 423 (or 422) on the opposite side of the first conductor portion 2a (i.e., the second conductor portion 2b side) can be omitted, but it is more desirable to form the plating layers 422 and 423 on both sides of the metal layer 421 to prevent discoloration of the metal layer 421, etc. By using a tape member composed of a tape member 41a or copper tape 42 as shown in Figures 3(b) and 3(c) as the electrolytic corrosion suppression member 4, the conductivity of the electrolytic corrosion suppression member 4 can be increased compared to a tape member 41 in which a conductive adhesive 413 is placed between the first metal layer 411 and the second metal layer 412. Therefore, when the electrolytic corrosion suppression member 4 is placed inside the conductor 2, the conductivity of the conductor 2 is less likely to decrease.

[0047] However, since the copper tape 42 is relatively hard, wear may occur on the first conductor portion 2a at the edges (the steps that occur in the overlapping portions). Also, when crimping the ends of the conductor 2 to form terminals, the plating layer 422 (or 423) on the first conductor portion 2a side may peel off, making it easier for galvanic corrosion to occur. Therefore, as shown in Figure 3(d), the galvanic corrosion suppression member 4 may further have an aluminum tape 43 made of aluminum or an aluminum alloy on the first conductor portion 2a side of the copper tape 42. In this case, the aluminum tape 43 and the copper tape 42 are arranged to be in direct contact without an adhesive member in between. That is, the aluminum tape 43 may be wound spirally around the first conductor portion 2a, and then the copper tape 42 may be wound spirally on the aluminum tape 43 to constitute the galvanic corrosion suppression member 4. The winding direction of the aluminum tape 43 should be the same as the winding direction of the copper tape 42.

[0048] As a result, the aluminum tape 43 acts as a buffer layer, suppressing wear of the first conductor portion 2a due to friction with the copper tape 42. Furthermore, even if the plating layers 422 and 423 peel off for some reason, such as crimping of terminals fixed to the end of the conductor 2, the metal layer 421 is prevented from directly contacting the first conductor portion 2a, thereby preventing galvanic corrosion of the first conductor portion 2a. For example, in addition to the tape member 41 in Figure 3(a) and the tape member 41a in Figure 3(b), the aluminum tape 43 can also be provided on the side of the first conductor portion 2a.

[0049] (Variation of Conductor 2) In this embodiment, the first conductor section 2a and the second conductor section 2b are made of a composite stranded wire formed by twisting together stranded wires 21 and 22. However, the invention is not limited to this, and the first conductor section 2a and the second conductor section 2b may be made of a stranded wire formed by twisting together single metal strands. In other words, the first conductor section 2a may be made by twisting together a plurality of first strands 211 made of aluminum or an aluminum alloy, and the second conductor section 2b may be made by twisting together a plurality of second strands 221 made of copper or a copper alloy in a spiral shape around the galvanic corrosion suppression member 4.

[0050] Furthermore, as shown in Figure 4(a), the first conductor portion 2a, which is made of aluminum or an aluminum alloy, may be a compressed conductor. For example, the first conductor portion 2a, which is made of a compressed conductor, can be formed by twisting together several first strands 211 (seven in the illustrated example) and then passing them through a wire drawing die to compress them. The galvanic corrosion suppression member 4 is provided around the first conductor portion 2a, which is made of a compressed conductor, and the second conductor portion 2b is formed by twisting together several second strands 221, which are made of copper or a copper alloy, around the galvanic corrosion suppression member 4. The second conductor portion 2b may also be compressed.

[0051] Furthermore, as shown in Figure 4(b), the first conductor portion 2a, made of aluminum or an aluminum alloy, may be composed of a single wire having an annular outer surface. In this case, the outer diameter of the first strand 211 constituting the first conductor portion 2a is preferably larger than the outer diameter of the multiple second strands 221 constituting the second conductor portion 2b. In this case as well, the second conductor portion 2b may be compressed.

[0052] The structure of the first conductor portion 2a as shown in Figures 4(a) and 4(b) reduces the gap between the first conductor portion 2a and the corrosion suppression member 4, thereby increasing the contact area between the first conductor portion 2a and the second conductor portion 2b and the corrosion suppression member 4. As a result, the contact resistance between the first conductor portion 2a and the second conductor portion 2b and the corrosion suppression member 4 is reduced compared to the case of conductor 2 shown in Figure 1(a), and the electrical characteristics of conductor 2 can be further improved.

[0053] Furthermore, although this embodiment describes the case where the first conductor portion 2a and the second conductor portion 2b are stranded conductors, the invention is not limited to this, and the first conductor portion 2a and the second conductor portion 2b may be braided conductors. More specifically, as shown in Figure 5(a), the first conductor portion 2a may be a strip-shaped first braided conductor formed by braiding together a plurality of first strands 211 made of aluminum or an aluminum alloy, and the second conductor portion 2b may be a second braided conductor formed by braiding together a plurality of second strands 221 made of copper or a copper alloy.

[0054] In the example shown in Figure 5(a), the first conductor portion 2a is formed by flattening an annular braided conductor. For example, when manufacturing a coaxial cable, a braided conductor is provided around a core that has an insulator covering the conductor. However, in this embodiment, an annular braided conductor is formed without passing through a core, and then the braided conductor is flattened by pressing or the like to form the first conductor portion 2a. A tape member 41 is spirally wrapped around the first conductor portion 2a as an electrolytic corrosion suppression member 4.

[0055] The second conductor section 2b is formed in a cylindrical shape so as to cover the entire perimeter of the first conductor section 2a. The second conductor section 2b is formed by braiding the second strands in a ring shape around the first conductor section 2a, which is the core material. In this way, the first conductor section 2a, made of aluminum or an aluminum alloy, and the second conductor section 2b, made of copper or a copper alloy and arranged around it, are both made of braided conductors, and the galvanic corrosion suppression member 4 is placed between these braided conductors. This structure makes it easy to wire in a way that conforms to the shape of narrow wiring locations between devices, and suppresses the reduction in lifespan and deterioration of electrical characteristics due to galvanic corrosion. Furthermore, when connecting the wire 1 to a device, the connectors and terminals that were used when connecting conductors made only of copper or copper alloy to the device can be fixed to the end of the conductor 2 by a predetermined fixing method such as crimping. Therefore, the wire 1 and the device can be connected without using special connectors or terminals.

[0056] In the example shown in Figure 5(a), the case in which the second conductor portion 2b is provided so as to cover the entire periphery of the first conductor portion 2a has been described. However, the conductor 2 may be configured using a pair of strip-shaped second conductor portions 2b, as shown in Figure 5(b), so that the first conductor portion 2a is sandwiched between the pair of second conductor portions 2b in the thickness direction of the conductor 2. In Figure 5(b), the galvanic corrosion suppression member 4 is constructed by wrapping a tape member 41 around the periphery of the first conductor portion 2a. However, the galvanic corrosion suppression member 4 may be constructed by interposing a pair of sheet-shaped galvanic corrosion suppression members 4 between the first conductor portion 2a and the second conductor portion 2b, respectively, or by wrapping tape members 41 around each of the second conductor portions 2b. The same effect as in the example in Figure 5(a) can be obtained in the example in Figure 5(b).

[0057] (Cable 10) Next, a cable 10 using electric wires 1 will be described. Figure 6 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 6, the cable 10 comprises a cable core 11 containing a plurality of electric wires 1, and a sheath 12 provided to cover the periphery of the cable core 11 collectively.

[0058] The cable core 11 is constructed by twisting together adjacent wires 1 in the circumferential direction of the cable so that they are in contact with each other. In this embodiment, the cable core 11 is constructed by twisting together three wires 1 and multiple thread-like interlinings 14. The interlinings 14 are arranged to fill the gaps around the wires 1 (the area surrounded by the three wires 1 including the center of the cable and the area surrounded by adjacent wires 1 and the sheath 12) in order to make the outer shape of the cable 10 closer to a circular shape. In this embodiment, jute is used as the interlining 14. However, the interlining 14 is not limited to jute, and may be made of other materials such as rayon (staple fiber).

[0059] Furthermore, the cable 10 is further equipped with a retaining tape 13 that is spirally wrapped around the cable core 11. The retaining tape 13 serves to hold the twist of the cable core 11 in place so that it does not unravel. For example, nonwoven tape or paper tape can be used as the retaining tape 13. In this embodiment, a nonwoven tape (staple fiber tape) made of rayon (staple fiber) was used as the retaining tape 13.

[0060] The sheath 12 is provided so as to cover the perimeter of the retaining tape 13. More specifically, the sheath 12 has an annular cross-section (a cross-section perpendicular to the longitudinal direction of the cable) formed by tube extrusion, and is provided so as not to penetrate between adjacent electric wires 1. The sheath 12 is made of, for example, an irradiation-crosslinked resin composition that has been irradiated and crosslinked by electron beam irradiation. Specifically, the sheath 12 can be made of, for example, irradiation-crosslinked flame-retardant polyethylene (FRPE) with a heat resistance temperature of 125°C or higher.

[0061] (Operation and Effects of the Embodiment) As described above, in the electric wire 1 according to this embodiment, the conductor 2 has a first conductor portion 2a using first strands 211 made of aluminum or an aluminum alloy, and a second conductor portion 2b using second strands 221 made of copper or a copper alloy, and is provided as an electrochemical corrosion suppression member 4 interposed between the first conductor portion 2a and the second conductor portion 2b to suppress electrochemical corrosion between the first conductor portion 2a and the second conductor portion 2b.

[0062] By having a first conductor section 2a made of aluminum or an aluminum alloy in the conductor 2, the amount of expensive copper used can be reduced, resulting in a low-cost, lightweight, and flexible electric wire 1. As a result, handling during wiring can be improved, and transportation costs can be reduced by compactly bundling the wires during delivery. This invention is particularly useful for large-diameter electric wires 1 with a conductor cross-sectional area of ​​60 mm², where the amount of copper used would be high if the entire conductor 2 were made of copper or a copper alloy. 2 This is particularly effective for electric wires 1 with an outer diameter of 10 mm or more (60SQ) or larger.

[0063] Furthermore, in this embodiment, because the galvanic corrosion suppression member 4 is provided, it is possible to suppress the occurrence of galvanic corrosion caused by contact between the first conductor portion 2a, which is made of aluminum or an aluminum alloy, and the second conductor portion 2b, which is made of copper or a copper alloy. Therefore, even in environments with high humidity, for example, it is possible to suppress a decrease in lifespan and a decrease in electrical characteristics due to galvanic corrosion.

[0064] (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.

[0065] [1] An electric wire (1) comprising a conductor (2) and an insulator (3) provided to cover the conductor (2), wherein the conductor (2) has a first conductor portion (2a) using first strands (211) made of aluminum or an aluminum alloy and a second conductor portion (2b) using second strands (221) made of copper or a copper alloy, and an electrochemical corrosion suppression member (4) provided interposed between the first conductor portion (2a) and the second conductor portion (2b) to suppress electrochemical corrosion between the first conductor portion (2a) and the second conductor portion (2b).

[0066] [2] The electric wire (1) described in [1], wherein the first conductor portion (2a) is made up of a plurality of first strands (211) or a plurality of first sub-strands (21) made up of a plurality of first strands (211) twisted together, the galvanic corrosion suppression member (4) consists of one or more tape members (41-43) that are spirally wound around the first conductor portion (2a) by overlapping winding, and the second conductor portion (2b) is made up of a plurality of second strands (221) or a plurality of second sub-strands (22) made up of a plurality of second strands (221) twisted together, spirally wound around the galvanic corrosion suppression member (4).

[0067] [3] The electric wire (2) according to [2], wherein the twisting direction of the first conductor portion (2a) and the winding direction of the electrolytic corrosion suppression member (4) are in opposite directions, and the winding direction of the electrolytic corrosion suppression member (4) and the twisting direction of the second conductor portion (2b) are in the same direction.

[0068] [4] The electric wire (1) according to [1], wherein the first conductor portion (2a) is a first braided conductor formed by braiding together a plurality of first strands (211), and the second conductor portion (2b) is a second braided conductor formed by braiding together a plurality of second strands (221).

[0069] [5] The electric wire (1) described in [1], wherein the electrolytic corrosion suppression member (4) has a tape member (41, 41a) integrally having a first metal layer (411) made of aluminum or an aluminum alloy formed on one surface, a second metal layer (412) made of copper or a copper alloy formed on the other surface, and a plating layer (414) made of tin formed on the surface of the second metal layer, with the first metal layer (411) on the first conductor portion (2a) side and the second metal layer (412) on the second conductor portion (2b) side.

[0070] [6] The electric wire (1) according to [1], wherein the electrolytic corrosion suppression member (4) has a copper tape (42) on both sides of a metal layer (421) made of copper or a copper alloy, with tin plating layers (422, 423) formed on both sides.

[0071] [7] The electric wire (1) according to [6], wherein the electrolytic corrosion suppression member (4) is provided on the first conductor portion (2a) side of the copper tape (42) and further comprises an aluminum tape (43) made of aluminum or an aluminum alloy.

[0072] [8] The first conductor portion (2a) is a compressed conductor, as described in [1].

[0073] A cable (10) comprising a cable core (11) containing a plurality of electric wires (1) as described in any one of items [9][1] to [8], and a sheath (12) provided to cover the periphery of the cable core (11) collectively.

[0074] (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]

[0075] 1...Electric wire 2... Conductor 2a...First conductor section 2b...Second conductor section 21...First child stranded wire 211...First strand 22…Second child stranded wire 221...Second strand 3…Insulator 4…Electrolytic corrosion suppression member 41... Tape component 411...first metal layer 412…Second metal layer 413...Conductive adhesive layer 414…Plating layer 42… Copper tape 421...Metal layer 422,423…Plating layer 43…Aluminum tape 10… Cable 11… Cable core 12...Sheath

Claims

1. A conductor and The conductor comprises an insulator provided to cover the periphery of the conductor, The conductor comprises a first conductor portion using first strands made of aluminum or an aluminum alloy, and a second conductor portion using second strands made of copper or a copper alloy. The device includes an electrochemical corrosion suppression member that is interposed between the first conductor portion and the second conductor portion to suppress electrochemical corrosion between the first conductor portion and the second conductor portion, The electrolytic corrosion suppression member has a copper tape in which a tin plating layer is formed on both sides of a metal layer made of copper or a copper alloy. Electric wire.

2. The first conductor portion is formed by twisting together a plurality of first strands, or a plurality of first strands formed by twisting together a plurality of first strands. The electrolytic corrosion suppression member consists of one or more tape members that are spirally wound around the first conductor portion by overlapping windings. The second conductor portion is constructed by twisting a plurality of the second strands, or a second stranded wire formed by twisting a plurality of the second strands together, in a spiral manner around the electrolytic corrosion suppression member. The electric wire according to claim 1.

3. The twisting direction of the first conductor portion and the winding direction of the electrolytic corrosion suppression member are in opposite directions. The winding direction of the electrolytic corrosion suppression member and the twisting direction of the second conductor portion are in the same direction. The electric wire according to claim 2.

4. The first conductor portion is a first braided conductor formed by braiding together a plurality of the first strands, The second conductor portion is a second braided conductor formed by braiding together a plurality of the second strands. The electric wire according to claim 1.

5. The electrolytic corrosion suppression member is provided on the first conductor side of the copper tape and further comprises an aluminum tape made of aluminum or an aluminum alloy. The electric wire according to claim 1.

6. The first conductor portion is made of a compression conductor. The electric wire according to claim 1.

7. A conductor and The conductor comprises an insulator provided to cover the periphery of the conductor, The conductor comprises a first conductor portion using first strands made of aluminum or an aluminum alloy, and a second conductor portion using second strands made of copper or a copper alloy. The device includes an electrochemical corrosion suppression member that is interposed between the first conductor portion and the second conductor portion to suppress electrochemical corrosion between the first conductor portion and the second conductor portion, The electrolytic corrosion suppression member has a tape member integrally comprising a first metal layer made of aluminum or an aluminum alloy formed on one side, a second metal layer made of copper or a copper alloy formed on the other side, and a plating layer made of tin formed on the surface of the second metal layer. The first metal layer is provided on the first conductor side, and the second metal layer is provided on the second conductor side. Electric wire.

8. A cable core comprising a plurality of electric wires as described in any one of claims 1 to 7, A sheath is provided to cover the entire perimeter of the cable core, The included cable.

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