Aluminum wire with aluminum terminal

Abstract

To provide an aluminum wire with an aluminum terminal that ensures electrical conductivity and suppresses temperature rise after repeated energization.SOLUTION: An aluminum wire with aluminum terminal has a composition containing 0.01 mass% or more and 3.00 mass% or less of Fe and 0.01 mass% or more and 0.50 mass% or less of Si, with the remainder being Al and unavoidable impurities, and when crystal orientation analysis is performed on a cross section by an electron backscatter diffraction method, the percentage of a region having a GAM value of less than 2° in a measurement region is 20% to 50%. The aluminum wire with an aluminum-based conductor is made of a plurality of aluminum-based element wires having a wire diameter of 0.10 mm to 0.83 mm, the aluminum-based conductor being connected to the aluminum-based terminal via a connection portion in a state where the aluminum-based conductor is inserted into an insertion portion of the aluminum-based terminal, and in the cross section of the connection portion, the filling rate of the aluminum-based conductor in an annular internal region of the connection portion is 85% or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an aluminum-based electric wire with an aluminum-based terminal. [Background technology]

[0002] Traditionally, copper-based materials such as copper and copper alloys, which have high electrical conductivity, have been used for the conductors of power distribution cables. However, in recent years, with the aim of reducing workload through weight reduction, there has been a shift to conductors made of aluminum-based materials such as aluminum and aluminum alloys (hereinafter referred to as aluminum-based conductors).

[0003] For distribution wires that carry higher voltages, thicker conductors are used compared to conductors for indoor wiring. Therefore, when switching to aluminum-based conductors, which have a conductivity approximately two-thirds lower than that of copper, the conductors of the conventional thick distribution wires must be made even thicker, i.e., their cross-sectional area must be increased. For example, when such aluminum-based distribution conductors with large cross-sectional area are used to connect to equipment such as switchboards and data centers that must be routed in narrow, limited routing spaces, considerable force is required to bend the wires due to their rigidity during installation, making routing difficult.

[0004] To address this problem, the wire can be made soft and flexible by softening the coating material of the wire or by reducing the diameter of the multiple strands that make up the conductor.

[0005] However, when an aluminum-based conductor made of aluminum-based wires with a small wire diameter is connected to an aluminum-based terminal, the insulating oxide film formed on the surface of the aluminum-based wire makes it difficult to establish electrical continuity between the aluminum-based wires and the aluminum-based terminal, or between the aluminum-based wires themselves. In particular, when an aluminum-based electric wire with an aluminum-based terminal is repeatedly energized during use, the aluminum-based wires that were previously in contact with each other may move due to thermal expansion and contraction, exposing new surfaces of the aluminum-based wires, and an oxide film may form on the new surfaces, resulting in an increase in resistance. For this reason, it is necessary to connect the aluminum-based conductor to the aluminum-based terminal more firmly.

[0006] From the viewpoint of making the electric wire easier to bend, the wire diameter is 0.10 mm or more and 0.83 mm or less. As for the number of wires, the greater the number, the more contact there will be between the aluminum-based wires having an oxide coating at the connection between the terminal and the electric wire, increasing the resistance of the connection and increasing the amount of temperature rise when electricity is repeatedly passed through it, so it is particularly necessary that the number be 60 or more.

[0007] Patent Document 1 also discloses that in a terminal crimping structure for an aluminum electric wire in which a terminal is crimped to an aluminum electric wire consisting of a number of twisted wires and a coating that coats the twisted wires, in order to maintain the electrical characteristics of the connection regardless of changes in the environment when crimping a terminal to the aluminum electric wire, the compression rate of the conductor portion of the aluminum electric wire in the region of the wire barrel where conductivity with the aluminum electric wire is ensured is 50 to 70% in terms of the ratio of the cross-sectional area of ​​the conductor portion of the aluminum electric wire at the crimped portion to the cross-sectional area of ​​the conductor portion of the aluminum electric wire before crimping. However, there is room for further improvement in the technology of Patent Document 1. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2005-327690 A Summary of the Invention [Problem to be solved by the invention]

[0009] An object of the present disclosure is to provide an aluminum-based electric wire with an aluminum-based terminal that ensures electrical conductivity and further suppresses temperature rise after repeated current flow. [Means for solving the problem]

[0010] [1] An aluminum-based electric wire with an aluminum-based terminal, comprising: 0.01% by mass or more and 3.00% by mass or less of Fe and 0.01% by mass or more and 0.50% by mass or less of Si, with the remainder being Al and unavoidable impurities; when crystal orientation analysis is performed on a cross section by electron backscatter diffraction method, the area ratio of a region having a GAM value of less than 2° in a measurement region is 20% or more and 50% or less; and the aluminum-based electric wire is composed of a plurality of aluminum-based element wires having a wire diameter of 0.10 mm or more and 0.83 mm or less, the aluminum-based conductor being connected to the aluminum-based terminal via a connection part in a state where the aluminum-based conductor is inserted into an insertion part of the aluminum-based terminal, and in the cross section of the connection part, the filling factor of the aluminum-based conductor occupying an annular internal region of the connection part is 85% or more. [2] The aluminum-based electric wire with aluminum-based terminal according to the above [1], wherein the aluminum-based conductor further contains Zr in an amount of 0.01 mass % or more and 0.45 mass % or less. [3] The aluminum-based electric wire with aluminum-based terminal according to [1] or [2] above, wherein the aluminum-based conductor further contains one or more elements selected from the group consisting of Cu, Mn, Mg and Zn in a total amount of 0.01% by mass or more and 0.50% by mass or less. [4] The aluminum-based electric wire with aluminum-based terminal according to any one of [1] to [3] above, wherein in a cross section of the connection portion, a ratio of the number of aluminum-based element wires that account for 95% or less of an average area of ​​all the aluminum-based element wires in a cross section of a portion of the aluminum-based electric wire that is not inserted into the insertion portion to the total number of the aluminum-based element wires is 50% or more. [5] The aluminum-based electric wire with aluminum-based terminal according to any one of [1] to [4] above, wherein in a cross section of the connection, the proportion of aluminum-based wires having an aspect ratio (L1 / L2) of 1.1 or more, calculated by dividing the dimension (L1) of the longest straight line by the dimension (L2) of the shortest straight line perpendicular to the long straight line, to the total number of the aluminum-based wires, is 50% or more. [6] The aluminum-based electric wire with aluminum-based terminal according to any one of [1] to [5] above, wherein in a cross section of the connection portion, a ratio of the number of aluminum-based element wires that is 105% or more of an average circumferential length of all the aluminum-based element wires in a cross section of a portion of the aluminum-based electric wire that is not inserted into the insertion portion to the total number of the aluminum-based element wires is 50% or more. [7] The aluminum-based electric wire with an aluminum-based terminal according to any one of the above [1] to [6], wherein a ratio of the number of aluminum-based element wires in contact with the aluminum-based terminal in a cross section of the connection portion to the number of aluminum-based element wires arranged in an outermost layer of an aluminum-based conductor in a cross section of a portion of the aluminum-based electric wire not inserted into the insertion portion is 110% or more. Effect of the Invention

[0011] According to the present disclosure, it is possible to provide an aluminum-based electric wire with an aluminum-based terminal that ensures electrical conductivity and further suppresses temperature rise after repeated current passage. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing an example of a main configuration of an aluminum-based electric wire with an aluminum-based terminal according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a detailed description will be given based on an embodiment.

[0014] As a result of extensive research, the present inventors have found that by using an aluminum-based electric wire that is composed of aluminum-based wires having a predetermined wire diameter and that has predetermined composition and physical properties, and by controlling the internal structure of a connection portion that connects the aluminum-based electric wire to an insertion portion of an aluminum-based terminal, it is possible to ensure conductivity between the aluminum-based electric wire and the aluminum-based terminal, and further to suppress a temperature rise after repeated current passage through an aluminum-based electric wire with an aluminum-based terminal, and have completed the present disclosure based on this finding.

[0015] An aluminum-based electric wire with an aluminum-based terminal according to an embodiment has a composition containing 0.01% by mass or more and 3.00% by mass or less of Fe and 0.01% by mass or more and 0.50% by mass or less of Si, with the remainder being Al and unavoidable impurities, and when crystal orientation analysis is performed on a cross section by electron backscatter diffraction method, the area ratio of a region having a GAM value of less than 2° in a measurement region is 20% to 50%. The aluminum-based electric wire is made of a plurality of aluminum-based element wires having a wire diameter of 0.10 mm to 0.83 mm, and the aluminum-based conductor of the aluminum-based electric wire is connected to the aluminum-based terminal via a connection portion in a state where the aluminum-based conductor is inserted into an insertion portion of the aluminum-based terminal, and in the cross section of the connection portion, the filling rate of the aluminum-based conductor occupying an annular internal region of the connection portion is 85% or more.

[0016] Fig. 1 is a perspective view showing an example of a main configuration of an aluminum-based electric wire with an aluminum-based terminal of an embodiment. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. As shown in Figs. 1 and 2, an aluminum-based electric wire with an aluminum-based terminal 1 includes an aluminum-based electric wire 10 and an aluminum-based terminal 20.

[0017] As shown in Fig. 1, the aluminum-based electric wire 10 has an aluminum-based conductor wire 12, an insulating coating 13 covering the outer periphery of the aluminum-based conductor wire 12, and a sheath 14 covering the outer periphery of the insulating coating 13. At one end side of the aluminum-based electric wire 10 (the left end side in Fig. 1), the insulating coating 13 covering the outer periphery of the aluminum-based conductor wire 12 and the sheath 14 covering the outer periphery of the insulating coating 13 are stripped from the aluminum-based electric wire 10, exposing the aluminum-based conductor wire 12.

[0018] One end side (the right end side in FIG. 1 ) of the aluminum-based terminal 20 is provided with a tubular insertion portion 21 into which the aluminum-based conductor 12 exposed at one end side of the aluminum-based electric wire 10 is inserted. When the insertion portion 21 of the aluminum-based terminal 20 is crimped with the aluminum-based conductor 12 of the aluminum-based electric wire 10 inserted into the insertion portion 21 of the aluminum-based terminal 20, the insertion portion 21 is crimped to the aluminum-based electric wire 10 so as to cover the outer periphery of the aluminum-based conductor 12. When the insertion portion 21 of the aluminum-based terminal 20 is crimped to the aluminum-based conductor 12, a connection portion 21a is formed in the insertion portion 21. The aluminum-based terminal 20 is electrically connected to the aluminum-based conductor 12 via the connection portion 21a.

[0019] A flat shuttlecock portion 22 is provided on the other end side of the aluminum-based terminal 20. For example, the shuttlecock portion 22 has a through hole 22a. By inserting a fastening member (not shown) such as a bolt through the through hole 22a of the shuttlecock portion 22, the aluminum-based terminal 20 is electrically connected to a terminal block (not shown).

[0020] The aluminum-based conductor wire 12 of the aluminum-based electric wire 10 is composed of a plurality of aluminum-based element wires 11. The aluminum-based conductor wire 12 may be a stranded wire in which a plurality of aluminum-based element wires 11 are stranded together as shown in Fig. 1, or a bundled wire in which a plurality of aluminum-based element wires 11 are bundled together.

[0021] The external shape of the cross section of the aluminum-based conductor wire 12 perpendicular to the longitudinal direction L of the aluminum-based electric wire 10 may be circular as shown in Fig. 1, or may be flat. The aluminum-based conductor wire 12 may be compressed.

[0022] The composition of the aluminum-based wires 11 constituting the aluminum-based electric wire 10, i.e., the composition of the aluminum-based conductor wire 12, contains 0.01 mass % or more and 3.00 mass % or less of Fe and 0.01 mass % or more and 0.50 mass % or less of Si, with the remainder being Al and unavoidable impurities.

[0023] Fe (iron) is an element that improves the strength of the aluminum-based wire 11 and the aluminum-based conductor 12. The content of Fe contained in the aluminum-based conductor is 0.01% by mass or more, preferably 0.05% by mass or more, and more preferably 0.10% by mass or more. When the content of Fe is 0.01% by mass or more, the strength of the aluminum-based wire is improved, and the tensile strength and impact resistance of the connection part (crimped part) between the end of the stranded wire (aluminum-based conductor) in which multiple aluminum-based wires are stranded and the aluminum-based terminal can be improved. In addition, the content of Fe contained in the aluminum-based conductor is 3.00% by mass or less, and when high conductivity is required, a smaller Fe content is better, so that the content is preferably 0.25% by mass or less.

[0024] Si (silicon) is an element that improves the strength of the aluminum-based wire 11 and the aluminum-based conductor 12. The Si content of the aluminum-based conductor is 0.01% by mass or more, and preferably 0.05% by mass or more. When the Si content is 0.01% by mass or more, the strength of the aluminum-based wire increases, and the deterioration of the crimped part strength and impact resistance at the connection part can be sufficiently suppressed. In addition, the Si content of the aluminum-based conductor is 0.50% by mass or less, preferably 0.20% by mass or less, and more preferably 0.15% by mass or less. When the Si content exceeds 0.50% by mass, the electrical conductivity decreases, which becomes a practical problem.

[0025] Furthermore, when the Al (aluminum) content is 96.30 mass % or more, the electrical conductivity of the aluminum-based element wire 11 and the aluminum-based conductor wire 12 can be improved, and alloying due to added elements can be prevented. Furthermore, the aluminum-based conductor wire is more likely to deform at the connection between the aluminum-based conductor wire and the aluminum-based terminal. As a result, the contact resistance decreases, and electrical continuity becomes easier. From this viewpoint, the Al content is preferably 99.70 mass % or more. In terms of alloy number, a pure aluminum composition such as A1070 or A1080 is preferable.

[0026] Furthermore, when the aluminum-based conductor further contains 0.01% by mass or more and 0.45% by mass or less of Zr (zirconium), not only the strength of the aluminum-based element wire 11 or the aluminum-based conductor wire 12 can be improved, but also the heat resistance can be improved. Therefore, even if the aluminum-based conductor wire is used in a place where the surrounding temperature is high or the temperature rises due to self-heating caused by current flow, the decrease in tensile strength can be suppressed. The lower limit of the Zr content is more preferably 0.02% by mass or more, and even more preferably 0.05% by mass or more. The upper limit of the Zr content is more preferably 0.15% by mass or less, and even more preferably 0.10% by mass or less.

[0027] Furthermore, if the aluminum-based conductor further contains one or more elements selected from the group consisting of Cu (copper), Mn (manganese), Mg (magnesium) and Zn (zinc) in a total amount of 0.01% by mass or more and 0.50% by mass or less, the strength of the aluminum-based element wire 11 and the aluminum-based conductor wire 12 can be improved, and the tensile strength and impact resistance at the connection between the end of the stranded wire (aluminum-based conductor wire) in which multiple aluminum-based element wires are stranded and the aluminum-based terminal can be improved. On the other hand, if the aluminum-based conductor wire contains too many of these elements, the electrical conductivity decreases. Therefore, the lower limit of the total amount of the one or more elements is more preferably 0.05% by mass or more, and even more preferably 0.10% by mass or more. The upper limit of the total amount is more preferably 0.40% by mass or less, and even more preferably 0.30% by mass or less.

[0028] The remainder other than the above-mentioned components are unavoidable impurities. The unavoidable impurities may be unavoidably contained in the manufacturing process, and depending on the content, may be a factor in reducing the electrical conductivity and strength of the aluminum-based element wire 11 and the aluminum-based conductive wire 12. Therefore, it is preferable that the content of the unavoidable impurities is small. Examples of the unavoidable impurities include elements such as Ni (nickel), Cr (chromium), V (vanadium), and Ga (gallium). The upper limit of the content of the unavoidable impurities is preferably 0.500 mass% or less, more preferably 0.010 mass% or less, in terms of the total of the above elements.

[0029] Moreover, the composition of aluminum-based terminal 20 is preferably a pure aluminum composition such as A1070 or A1080, from the viewpoint of lowering contact resistance and facilitating electrical continuity.

[0030] When a crystal orientation analysis is performed by electron backscatter diffraction (EBSD) on the cross section of the aluminum-based conducting wire 12 having the above composition, the area ratio of the region having a GAM value of less than 2° to the measurement region (hereinafter simply referred to as the area ratio of the region) is 20% to 50%. The cross section of the aluminum-based conducting wire 12 is a cross section perpendicular to the longitudinal direction L of the aluminum-based conducting wire 12 in the portion of the aluminum-based electric wire 10 that is not inserted into the insertion portion 21 of the aluminum-based terminal 20.

[0031] When the area ratio of the above region is 20% or more, a certain number of crystal grains having a small GAM value of less than 2° are present, and therefore when the insertion portion 21 is crimped while the aluminum-based conductor wire 12 is inserted into the insertion portion 21, the aluminum-based conductor wire 12 is easily deformed at the connection portion 21a, and the oxide coating of the aluminum-based element wire 11 and the aluminum-based conductor wire 12 can be easily destroyed. As a result, the conductivity between the aluminum-based electric wire 10 and the aluminum-based terminal 20 is ensured, and furthermore, the temperature rise after repeated current application of the aluminum-based electric wire 1 with the aluminum-based terminal can be suppressed. In addition, when the area ratio of the above region is 50% or less, breakage of the aluminum-based element wire 11 and the aluminum-based conductor wire 12 due to the excessive number of crystal grains having a small GAM value of less than 2°, which cannot withstand tension and bending during installation, can be suppressed. From this viewpoint, the lower limit of the area ratio of the above region is 20% or more, preferably 30% or more, and the upper limit of the area ratio of the above region is 50% or less, preferably 45% or less.

[0032] The GAM (grain average misorientation) value indicates the average misorientation between adjacent measurement points within the same crystal grain. The GAM value can be obtained from crystal orientation analysis data that is calculated (processed) by using an EBSD detector (TSL, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope (JEOL, JSM-7001FA) to continuously measure crystal orientation data, and the measured crystal orientation data is calculated (processed) using analysis software (TSL, OIM Analysis). "EBSD" is an abbreviation for Electron Backscatter Diffraction, and is a crystal orientation analysis technique that uses the backscattered electron Kikuchi diffraction that occurs when an electron beam is irradiated on an aluminum-based conductor, which is a measurement sample, in a scanning electron microscope (SEM).

[0033] The measurement object is a surface of a cut surface (cross section of an aluminum-based conductor) cut perpendicular to the longitudinal direction of an aluminum-based conductor, which is polished to a mirror finish, and the measurement area is 25 μm × 60 μm. The measurement is performed with a step size of 0.1 μm. Using analysis software, the area ratio of the area having a GAM value of less than 2° is calculated by Map-Grain Average Misorientation. This measurement is performed multiple times, for example, three times (n = 3), and the average value is calculated to be the above-mentioned area ratio. Note that the above-mentioned measurement is performed by regarding the boundary where the orientation difference between adjacent measurement points is 5° or more as the grain boundary surface.

[0034] Furthermore, the diameter (wire diameter) of the plurality of aluminum-based element wires 11 constituting the aluminum-based conductor wire 12 is 0.10 mm or more and 0.83 mm or less. When the diameter of the aluminum-based element wires 11 is within the above range, the aluminum-based conductor wires 12 of the aluminum-based electric wire 10 can be bent softly and flexibly while ensuring electrical conductivity and suppressing temperature rise after repeated current passing through the wires.

[0035] The aluminum-based electric wire 1 with aluminum-based terminal is composed of a plurality of aluminum-based element wires 11 having the above-mentioned wire diameter, and the aluminum-based conductor wire 12 having the above-mentioned composition and area ratio is connected to the aluminum-based terminal 20 via the connection part 21a in a state where it is inserted into the insertion part 21 of the aluminum-based terminal 20. As shown in Figures 1 and 2, in a cross section of the connection part 21a in the insertion part 21 of the aluminum-based terminal 20, the filling rate of the aluminum-based conductor wire 12 in the annular internal region 21b of the connection part 21a is 85% or more. The cross section of the connection part 21a is a cross section of the connection part 21a perpendicular to the longitudinal direction L of the aluminum-based conductor wire 12.

[0036] When the filling rate of the area of ​​the aluminum-based conductor 12 in the area of ​​the annular inner region 21b in the cross section of the connection portion 21a is 85% or more, the ratio of the aluminum-based element wires 11 constituting the aluminum-based conductor 12 to each other increases, so that the oxide film between the aluminum-based element wires 11 is easily destroyed, and the resistance of the aluminum-based conductor 12 is low. In addition, even after the aluminum-based electric wire 1 with aluminum-based terminal is repeatedly energized, it is not easily affected by thermal expansion and contraction, and can maintain low resistance. On the other hand, when the filling rate is less than 85%, the oxide film between the aluminum-based element wires 11 is not easily destroyed, and the resistance of the aluminum-based conductor 12 is not easily reduced. In addition, the aluminum-based electric wire 1 with aluminum-based terminal is easily increased in resistance after repeatedly energized, generating heat, and in the worst case, may catch fire.

[0037] In addition, in the cross section of the connecting portion 21a, the ratio of the number of aluminum-based element wires 11 that is 95% or less of the average area of ​​all the aluminum-based element wires 11 in the cross section of the portion not inserted into the insertion portion 21 of the aluminum-based electric wire 10 (hereinafter also simply referred to as the uninserted portion) to the total number of the aluminum-based element wires 11 is preferably 50% or more. In this way, if the ratio of the number of aluminum-based element wires 11 in the annular inner region 21b that has an area (cross-sectional area) that is 95% or less of the average area of ​​all the aluminum-based element wires in the cross section of the uninserted portion to the total number of the aluminum-based element wires 11 in the annular inner region 21b is 50% or more, the number of deformed (crushed) aluminum-based element wires 11 is large, so that the oxide film destruction of the aluminum-based element wires 11 further occurs, and the resistance of the aluminum-based conductor wire 12 further decreases.

[0038] Furthermore, in the cross section of the connection portion 21a, the proportion of aluminum-based wires having an aspect ratio (L1 / L2) of 1.1 or more, calculated by dividing the dimension (L1) of the longest straight line by the dimension (L2) of the shortest straight line perpendicular to the long straight line, to the total number of aluminum-based wires 11 is preferably 50% or more. In this way, when the proportion of aluminum-based wires having an aspect ratio (L1 / L2) of 1.1 or more to the total number of aluminum-based wires 11 is 50% or more, the number of deformed aluminum-based wires 11 is large, so that the oxide film destruction of the aluminum-based wires 11 further occurs, and the resistance of the aluminum-based conducting wire 12 further decreases.

[0039] In addition, in the cross section of the connecting portion 21a, the ratio of the number of aluminum-based element wires 11 that is 105% or more of the average circumferential length of all the aluminum-based element wires 11 in the cross section of the portion of the aluminum-based electric wire 10 that is not inserted into the insertion portion 21 is preferably 50% or more relative to the total number of the aluminum-based element wires 11. In this way, when the ratio of the number of aluminum-based element wires 11 in the annular inner region 21b that has a circumferential length that is 105% or more of the average circumferential length of all the aluminum-based element wires in the cross section of the non-inserted portion relative to the total number of the aluminum-based element wires 11 in the annular inner region 21b is 50% or more, the number of deformed aluminum-based element wires 11 is large, so that the oxide film destruction of the aluminum-based element wires 11 further occurs, and the resistance of the aluminum-based conductor wire 12 further decreases.

[0040] Also, the ratio of the number of aluminum-based element wires 11 in contact with the aluminum-based terminal 20 in the cross section of the connection portion 21a to the number of aluminum-based element wires 11 arranged in the outermost layer of the aluminum-based conductor wire 12 in the cross section of the portion of the aluminum-based electric wire 10 that is not inserted into the insertion portion 21 is preferably 110% or more. In this way, when the ratio of the number of aluminum-based element wires 11 in the annular inner region 21b that is in contact with the insertion portion 21 of the aluminum-based terminal 20 in the cross section of the connection portion 21a to the number of aluminum-based element wires arranged in the outermost layer (outermost circumference) in the cross section of the non-inserted portion is 110% or more, the number of deformed aluminum-based element wires 11 is large, so that further destruction of the oxide film of the aluminum-based element wires 11 occurs, and the resistance of the aluminum-based conductor wire 12 is further reduced.

[0041] Even if the number of aluminum-based element wires 11 constituting the aluminum-based conductor wire 12 is 60 or more, the aluminum-based electric wire 1 with aluminum-based terminal can ensure electrical conductivity and further suppress temperature rise after repeated current passage.

[0042] Such an aluminum-based electric wire with aluminum-based terminal can ensure conductivity and suppress temperature rise after repeated current passage, even when multiple aluminum-based wires with thin wire diameter are used in the aluminum-based conductor. Furthermore, since the aluminum-based electric wire can be bent softly and flexibly, it can be suitably used in devices that require bending for wiring in a narrow space, such as switchboards and data centers. There is no risk of fire when connecting the aluminum-based electric wire with aluminum-based terminal, so it can be used safely and securely.

[0043] Next, an example of a method for producing the aluminum-based electric wire 1 with the aluminum-based terminal will be described.

[0044] First, there will be described an example of a method for producing the aluminum-based electric wire 10. The method for producing the aluminum-based electric wire 10 includes a continuous casting and rolling step, a heat treatment step, a first wire drawing step, a second wire drawing step, a stranding step, and an extrusion step.

[0045] In the continuous casting and rolling process, various raw materials are selected so as to obtain a desired composition, and then cast and rolled to obtain a wire rod. In this process, it is preferable to use a Properti type continuous casting and rolling machine combining a casting wheel and a belt, which can continuously pour molten metal into a ring-shaped groove mold to cast the wire, and then continuously roll the wire to obtain a wire rod, from the viewpoint of manufacturing efficiency.

[0046] After the continuous casting and rolling process, a heat treatment process is performed at 350°C to 450°C. The heat treatment process is performed for the purpose of homogenizing the composition and metal structure by recrystallizing it, and for the purpose of precipitating intermetallic compounds to improve electrical conductivity. In addition, the aluminum-based wire rod after the second wire drawing process described below is more likely to have a desired GAM value. The heat treatment process can be performed using a method such as batch heat treatment or high-frequency heating.

[0047] After the heat treatment process, a first wiredrawing process is performed in which continuous wiredrawing (warm wiredrawing) is performed in a heating furnace at 150°C or more and less than 250°C. If the temperature is less than 150°C, it becomes difficult to obtain the desired GAM value in the aluminum-based wire after the second wiredrawing process described below, and if the temperature is 250°C or more, the aluminum-based wire becomes too soft and breaks, making it impossible to draw. The processing rate of the first wiredrawing process is 80% or more and 98% or less so that the desired GAM value is easily obtained when the aluminum-based electric wire is manufactured. The processing rate is calculated by dividing the cross-sectional area of ​​the wire after wiredrawing by the cross-sectional area of ​​the wire before wiredrawing and multiplying the result by 100.

[0048] After the first wiredrawing step, a second wiredrawing step is performed in which cold drawing is performed to obtain an aluminum-based wire. The working ratio of the second wiredrawing step is 50% or more and 99% or less.

[0049] In this way, by properly controlling the continuous casting and rolling process, the composition of the aluminum-based wire can be kept within a predetermined range. Also, by properly controlling the heat treatment process, the first wiredrawing process, and the second wiredrawing process, the area ratio of the region having a GAM value of less than 2° to the measurement region in the cross section of the aluminum-based wire can be made 20% or more and 50% or less.

[0050] After the second wire drawing step, a stranding step is performed in which a plurality of aluminum-based element wires are stranded together using a stranding machine to obtain a stranded aluminum-based conductor wire. When the aluminum-based conductor wire is a bundled wire, the aluminum-based conductor wire is obtained by bundling a plurality of aluminum-based element wires.

[0051] After the stranding step, an extrusion step is carried out to coat the outer periphery of the aluminum-based conductor wire with an insulating coating and a sheath, thereby obtaining an aluminum-based electric wire.

[0052] Next, in order to improve the adhesion between the aluminum-based conductor 12 of the aluminum-based electric wire 10 and the insertion portion 21 of the aluminum-based terminal 20, a compound insertion step is performed in which a compound material (not shown) is applied to the inside of the insertion portion 21. The compound material is mainly composed of mineral oil and zinc powder, and is used to satisfactorily connect the aluminum-based conductor 12 and the insertion portion 21. When the compound material is provided inside the insertion portion 21, the compound material plays a role of ensuring good conductivity of the aluminum-based electric wire 1 with aluminum-based terminal, destroying the oxide film of the aluminum-based conductor 12 and the oxide film of the insertion portion 21, waterproofing the connection portion 21a, etc.

[0053] After the compound insertion step, the aluminum-based conducting wire 12 is inserted into the insertion portion 21 of the aluminum-based terminal 20, and a crimping or compressing step is performed in which a force is applied to the insertion portion 21 using a crimping device or a compression device to connect the aluminum-based conducting wire 12 and the insertion portion 21. In the crimping step, a force is applied to the insertion portion 21 in one direction, and in the compression step, a force is applied isotropically to the insertion portion 21. In this manner, an aluminum-based electric wire with an aluminum-based terminal can be obtained.

[0054] It is also preferable to apply ultrasonic vibrations at the same time as applying force to the insertion portion 21. The time for applying ultrasonic vibrations may be changed. When ultrasonic vibrations are applied, the aluminum-based conductive wire 12 moves so as to eliminate voids within the insertion portion 21, thereby increasing the filling rate at the connection portion 21a. The filling rate can also be controlled by changing the speed of crimping or compression. This makes it easier to obtain a predetermined connection state at the connection portion 21a, and further suppresses the initial resistance of the connection portion 21a and the amount of temperature rise after repeated current application.

[0055] According to the embodiment described above, by using an aluminum-based electric wire that is made up of aluminum-based wires having a predetermined wire diameter and has predetermined composition and physical properties, and by controlling the internal structure of the connection portion in the insertion portion of the aluminum-based terminal, it is possible to ensure conductivity between the aluminum-based electric wire and the aluminum-based terminal and to suppress a temperature increase after repeated current passage through the aluminum-based electric wire with the aluminum-based terminal.

[0056] Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes all aspects included in the concept and scope of the claims of the present disclosure, and can be modified in various ways within the scope of the present disclosure. EXAMPLES

[0057] Next, examples and comparative examples will be described, but the present invention is not limited to these examples.

[0058] (Examples 1 to 18, Comparative Examples 1 to 6) Various raw materials were selected so as to obtain the composition shown in Table 1, and a continuous casting and rolling process was performed using a continuous casting and rolling machine (manufactured by Properti) to obtain an aluminum-based rough wire. The composition in Table 1 was confirmed by a component analysis of the aluminum-based rough wire. Next, the aluminum-based rough wire was subjected to a heat treatment process at 450°C for 2 hours, and then a first wiredrawing process and a second wiredrawing process were performed under the conditions shown in Table 2 to obtain an aluminum-based element wire having a wire diameter shown in Table 2.

[0059] The obtained aluminum-based wires were twisted together using a twisting machine to obtain an aluminum-based conductor having the twisted structure shown in Table 2. Then, cross-linked polyethylene was arranged at a thickness of 2.0 mm on the outer peripheral surface of the aluminum-based conductor to obtain an insulated wire with an outer diameter of 18.7 mm, and then a PVC resin mixture was coated on the outer peripheral surface of the insulated wire to form a sheath with a thickness of 1.5 mm, thereby obtaining an aluminum-based electric wire with an outer diameter of 21.7 mm.

[0060] Next, a compound material (Compound A, manufactured by Furukawa Power Systems Co., Ltd.) was applied to the inside of the insertion part of the aluminum-based terminal. Then, the aluminum-based conductor of the obtained aluminum-based electric wire was inserted into the insertion part, and the insertion part was crimped while being subjected to ultrasonic vibration of 20 kHz using a crimping device or a compression device, thereby connecting the aluminum-based conductor and the insertion part to form a connection part. In this way, the aluminum-based conductor of the aluminum-based electric wire and the insertion part of the aluminum-based terminal were electrically connected via the connection part to obtain an aluminum-based electric wire with an aluminum-based terminal having the configuration shown in Table 2.

[0061] [Measurement and Evaluation] The aluminum-based electric wires with aluminum-based terminals obtained in the above Examples and Comparative Examples were subjected to the following measurements and evaluations. The results are shown in Table 3.

[0062] [1] GAM value The GAM value was obtained from the crystal orientation analysis data, which was calculated (processed) by using an EBSD detector (TSL, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope (JEOL, JSM-7001FA) to continuously measure crystal orientation data, and the measured crystal orientation data was calculated (processed) by analysis software (TSL, OIM Analysis). The measurement object was a surface of a cut surface of an aluminum-based conductor cut perpendicular to the longitudinal direction and polished to a mirror finish, and the measurement area was 25 μm × 60 μm. The measurement was performed with a step size of 0.1 μm. The area ratio of the area having a GAM value of less than 2° in the measurement area was calculated by Map-Grain Average Misorientation using the analysis software. This measurement was performed three times (n = 3), and the average value was taken as the area ratio of the area having a GAM value of less than 2° in the measurement area.

[0063] [2] Filling rate, wire cross-sectional area, aspect ratio (L1 / L2), perimeter, number of wires in contact with aluminum terminal The cross sections of the connection part and the part not inserted into the insertion part were observed with an optical microscope and the measurements were made using image processing software. Each cross section was polished to a mirror finish.

[0064] [3] Initial resistance The shuttlecock parts of two aluminum-based electric wires with aluminum-based terminals obtained in each Example and Comparative Example (aluminum-based electric wires with a total length of 400 mm, both ends of which had aluminum-based terminals connected) were bolted to a terminal block for aluminum-based terminals (manufactured by Fuji Denki Kogyo Co., Ltd.) with a torque of about 23 N·m, and the aluminum-based electric wires with aluminum-based terminals, the terminal block, and the aluminum-based electric wires with aluminum-based terminals were arranged in a straight line. The aluminum terminal on the side of the aluminum-based electric wire with aluminum-based terminal that was not fastened to the terminal block was clamped with an alligator clip, and the resistance was measured using the four-terminal method. In the resistance measurement, after the resistance measurement, the bolt was once loosened and then fastened again to measure the resistance, which was carried out three times, and the average value was taken as the initial resistance. Since the initial resistance changes depending on the size of the electric wire, it was calculated by multiplying the initial resistance (mΩ) by the wire size (mm 2) and the normalized initial resistance was 55 (mΩ mm 2 ) or less, it was deemed to have passed the test as it was deemed that heat generation could be suppressed.

[0065] [4] Heat cycle test To evaluate the temperature rise after repeated current application, a heat cycle test was performed with reference to the heat cycle test described in "JIS C 2810 General Rules for Electric Wire Connectors for Indoor Wiring - Non-separable Type". Two aluminum-based electric wires with aluminum-based terminals (having the same length of 2m or more) obtained in each example and each comparative example were prepared, and the aluminum-based terminals were connected in series via a terminal block, and a current value was set so that the temperature of the aluminum-based electric wire would be 105°C. A slit was made in an arbitrary central part of the insulation coating of the aluminum-based electric wire, and a thermocouple was inserted so as to contact the aluminum-based conductor of the aluminum-based electric wire, and the temperature of the aluminum-based electric wire was measured. In addition, a thermocouple was soldered to the shuttlecock part of the aluminum-based terminal to measure the temperature of the aluminum-based terminal. A process of applying current at a set current value for 1 hour and then stopping the current for 1 hour was defined as one cycle, and the temperature rise (°C) of the aluminum-based terminal after 500 cycles was measured in comparison with the temperature of the aluminum-based terminal after 25 cycles. In terms of suppressing heat generation in the aluminum-based electric wire with the aluminum-based terminal, the smaller the temperature rise, the better.

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] As shown in Tables 1 to 3, in the above examples, an aluminum-based electric wire made of aluminum-based element wires having a predetermined wire diameter and having a predetermined composition and physical properties was used, and the internal structure of the connection part at the insertion part of the aluminum-based terminal was controlled to a predetermined configuration, so that the initial resistance was low and the temperature rise after repeated current application could be suppressed. The aluminum-based electric wire with aluminum-based terminal of such examples has an aluminum-based conductor made of aluminum-based element wires having a small wire diameter, so it can be bent softly and flexibly. On the other hand, in the above comparative examples, the composition of the aluminum-based electric wire was outside the predetermined range, or the physical properties of the aluminum-based electric wire were outside the predetermined range, so that the internal structure of the connection part could not be controlled to a predetermined configuration, and therefore the initial resistance was high and the temperature rise after repeated current application could not be suppressed. [Explanation of symbols]

[0070] 1. Aluminum-based wire with aluminum-based terminal 10. Aluminum-based electric wires 11 Aluminum-based wire 12 Aluminum conductor 13 Insulating coating 14 Sheath 20 Aluminum terminals 21 Insertion section 21a Connection 21b Circular inner region 22 Battledore Club 22a Through hole

Claims

1. an aluminum-based electric wire having an aluminum-based conductor comprising a plurality of aluminum-based element wires having a wire diameter of 0.10 mm or more and 0.83 mm or less, the aluminum-based electric wire having an aluminum-based conductor having an aluminum-based conductor wire and an aluminum-based terminal connected to the aluminum-based terminal via a connection portion in a state where the aluminum-based conductor wire is inserted into an insertion portion of the aluminum-based terminal, the aluminum-based electric wire ... electric wire is inserted into an insertion portion of the aluminum-based terminal, the aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based terminal connected to the aluminum-based terminal via a connection portion in a state where the aluminum-based electric wire is inserted into an insertion portion of the aluminum-based terminal, the aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based electric wire having an aluminum-based conductor wire and an aluminum-based electric wire In a cross section of the connection portion, the filling rate of the aluminum-based conductor in an annular internal region of the connection portion is 85% or more. Aluminum wire with aluminum terminals.

2. 2. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein the aluminum-based conductor further contains Zr in an amount of 0.01 mass % or more and 0.45 mass % or less.

3. 2. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein the aluminum-based conductor further contains one or more elements selected from the group consisting of Cu, Mn, Mg, and Zn in a total amount of 0.01 mass % to 0.50 mass %.

4. 4. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein in a cross section of the connection portion, a ratio of a number of aluminum-based element wires that account for 95% or less of an average area of ​​all the aluminum-based element wires in a cross section of a portion of the aluminum-based electric wire that is not inserted into the insertion portion to a total number of the aluminum-based element wires is 50% or more.

5. 4. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein in a cross section of the connection portion, a percentage of the number of aluminum-based wires having an aspect ratio (L1 / L2) of 1.1 or more, obtained by dividing the dimension (L1) of the longest straight line by the dimension (L2) of the shortest straight line perpendicular to the long straight line, relative to the total number of the aluminum-based wires, is 50% or more.

6. 4. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein in a cross section of the connection portion, a ratio of a number of aluminum-based element wires that is 105% or more of an average circumferential length of all the aluminum-based element wires in a cross section of a portion of the aluminum-based electric wire that is not inserted into the insertion portion to a total number of the aluminum-based element wires is 50% or more.

7. 4. The aluminum-based electric wire with aluminum-based terminal according to claim 1, wherein a ratio of the number of aluminum-based element wires in contact with the aluminum-based terminal in a cross section of the connection portion to the number of aluminum-based element wires arranged in an outermost layer of an aluminum-based conductor in a cross section of a portion of the aluminum-based electric wire not inserted into the insertion portion is 110% or more.

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