Terminal-equipped electric wire and method for manufacturing the same

Abstract

The present application provides a terminal-equipped electric wire capable of maintaining low resistance between a conductor and a terminal and sufficiently ensuring electrical connection and a manufacturing method thereof. The terminal-equipped electric wire has a terminal connected to a conductor by being compressed through a hollow portion, the material used for the conductor has a tensile strength greater than that of the material used for the terminal, the terminal has three or more compression portions in the length direction of the conductor, in a case where the cross-sectional area of the conductor is set as S (mm 2 ), the length in the length direction of the compression portion, that is, the compression width is set as W (mm), and the length in the length direction of the non-compression portion between adjacent compression portions, that is, the compression interval is set as L (mm), the value of the compression width W and the value of the compression interval L respectively satisfy the following relational expressions (1) and (2). 0.01 × S + 2.5 ≤ W ≤ 0.07 × S + 3.5... (1) -1.0 ≤ L ≤ 0.145 × S + 3.75... (2).

Description

Technical Field

[0001] This invention relates to terminal wires and methods for manufacturing the same. Background Technology

[0002] Previously, from the perspective of conductivity, wires with terminals, which connect the conductor and the terminal of the wire, used conductors and terminals made of copper or copper alloys. However, in recent years, from the perspective of lightweighting, research is being conducted on using aluminum materials (aluminum or aluminum alloys) to form conductors and terminals.

[0003] In addition, as prior art information related to the invention of this application, there is Patent Document 1.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 98 / 54790 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In terminald wires, the stress acting on the connection between the conductor and the terminal decreases over time. Consequently, the contact force between the conductor and the terminal decreases, and their resistance may increase. In particular, aluminum is more prone to stress mitigation than copper, making it susceptible to the aforementioned problems when connecting terminals made of aluminum to conductors made of aluminum. If current flows through the conductor when the resistance between the conductor and the terminal is high, heat will be generated in the terminald wire, which may become a major cause of wire breakage and poor contact.

[0009] Therefore, the object of the present invention is to provide a terminal wire and a method thereof that can maintain a low resistance between the conductor and the terminal and sufficiently ensure electrical connection.

[0010] Methods for solving problems

[0011] To address the aforementioned problems, this invention provides a terminald wire comprising: a wire including a conductor and an insulating layer covering the conductor; and a terminal having a hollow portion for insertion into the conductor exposed at the end of the wire. The terminal is connected to the conductor by compressing the hollow portion while the conductor is inserted within it. The tensile strength of the material used for the conductor is greater than the tensile strength of the material used for the terminal. The terminal has three or more compression portions along the length of the conductor. The cross-sectional area of ​​the conductor is defined as S (mm²). 2When the length of the compression section along the length direction, i.e. the compression width, is set to W (mm), and the length of the non-compression section located between adjacent compression sections along the length direction, i.e. the compression interval, is set to L (mm), the value of the compression width W and the value of the compression interval L satisfy the following relationships (1) and (2), respectively.

[0012] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0013] -1.0≤L≤0.145×S+3.75...(2)

[0014] Furthermore, to solve the aforementioned problems, the present invention provides a method for manufacturing a terminald wire, which comprises: a wire including a conductor and an insulating layer covering the conductor; and a terminal having a hollow portion for insertion into the conductor exposed at the end of the wire, wherein the hollow portion is compressed while the conductor is inserted into the hollow portion to connect with the conductor. The method for manufacturing the terminald wire includes: a preparation step of preparing a wire and a terminal for which the tensile strength of the material used for the conductor is greater than the tensile strength of the material used for the terminal; and a connection step of forming three or more compression portions on the terminal by compressing it three or more times while the conductor exposed at the end of the wire is inserted into the hollow portion, thereby connecting the terminal to the conductor. The connection step includes a step of forming a new compression portion between adjacent compression portions already formed, and the cross-sectional area of ​​the conductor is set to S (mm²). 2 When the length of the compression section along the length direction, i.e. the compression width, is set to W (mm), and the length of the non-compression section located between adjacent compression sections along the length direction, i.e. the compression interval, is set to L (mm), the compression section is formed in such a way that the value of the compression width W and the value of the compression interval L satisfy the following relationship (1) and (2) respectively.

[0015] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0016] -1.0≤L≤0.145×S+3.75...(2)

[0017] Invention Effects

[0018] According to the present invention, a terminal wire capable of maintaining low resistance between the conductor and the terminal and sufficiently ensuring electrical connection is provided, and a method thereof for manufacturing the same. Attached Figure Description

[0019] Figure 1(a) is a cross-sectional view of a terminal wire according to an embodiment of the present invention. Figure 1 (b) is an enlarged view of its A section.

[0020] Figure 2 Figures (a) to (c) in the diagram illustrate the manufacturing method of wires with terminals.

[0021] Figure 3 Figures (a) and (b) illustrate the behavior of the terminals and conductors during the formation of the third compression section.

[0022] Figure 4 This is an explanatory diagram showing the overview of a high-temperature environment exposure test.

[0023] Figure 5 This is an explanatory diagram illustrating the method for measuring resistivity.

[0024] Figure 6 (a) shows the measured resistivity R2 after a high-temperature environmental exposure test with varying compression width W.

[0025] Figure 6 (b) is a graph showing the measured resistivity R2 after a high-temperature environmental exposure test with varying compression interval L.

[0026] Figure 6 (c) is a diagram representing the overlapping state.

[0027] Figure 7 In the figure, (a) is a graph showing the measured results of the increase rate of resistivity after the high-temperature environmental exposure test when the compression width W is varied, and (b) is a graph showing the measured results of the increase rate of resistivity after the high-temperature environmental exposure test when the compression interval L is varied.

[0028] Figure 8 In the figure, (a) is a graph showing the relationship between the conductor cross-sectional area S and the compression width W in the region where the resistivity R2 is below 100% after the high-temperature environment exposure test, and (b) is a graph showing the relationship between the conductor cross-sectional area S and the compression interval L in the region where the resistivity R2 is below 100% after the high-temperature environment exposure test.

[0029] Figure 9 In the figure, (a) is a graph showing the relationship between the conductor cross-sectional area S and the compression width W in the region where the resistivity R2 is less than 100% and the resistivity increase rate is less than 20% after the high-temperature environment exposure test, and (b) is a graph showing the relationship between the conductor cross-sectional area S and the compression interval L in the region where the resistivity R2 is less than 100% and the resistivity increase rate is less than 20% after the high-temperature environment exposure test.

[0030] Symbol Explanation

[0031] 1: Wire with terminal, 2: Wire, 3: Conductor, 4: Insulation layer, 5: Terminal, 6: Cylindrical part, 7: Hollow part, 8: Extension part, 9: Bolt hole, 10: Compression part, 101: First compression part, 102: Second compression part, 103: Third compression part, 11: Uncompressed part. Detailed Implementation

[0032] [Implementation Method]

[0033] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0034] (Simplified structure of a wire with terminals)

[0035] Figure 1 (a) is a cross-sectional view of the terminal wire according to this embodiment. Figure 1 (b) is an enlarged view of its A section. For example... Figure 1 As shown in (a) and (b), the terminald wire 1 includes a wire 2 and a terminal 5. The terminald wire 1 can be used, for example, as a wiring material for use in buildings, wind turbines, railway vehicles, automobiles, etc.

[0036] The wire 2 has a conductor 3 and an insulation layer 4 covering the conductor 3. The conductor 3 can be a metal wire, a stranded wire formed by twisting multiple metal wires together, or a composite stranded wire formed by further twisting multiple stranded wires together. The metal material constituting the conductor 3 can be, for example, pure aluminum or an aluminum alloy (hereinafter referred to as "aluminum material"). Pure aluminum is a material composed of Al and unavoidable impurities.

[0037] Examples of pure aluminum include, for example, electrical grade pure aluminum (ECAl). Examples of aluminum alloys include, for example, Al-Zr and Al-Fe-Zr. Al-Zr is an aluminum alloy with the following chemical composition: containing 0.03 to 1.5% by mass of Zr and 0.1 to 1.0% by mass of Fe and Si, with the balance being Al and unavoidable impurities. Al-Fe-Zr is an aluminum alloy containing 0.01 to 0.10% by mass of Zr, less than 0.1% by mass of Si, 0.2 to 1.0% by mass of Fe, less than 0.01% by mass of Cu, less than 0.01% by mass of Mn, less than 0.01% by mass of Mg, less than 0.01% by mass of Zn, less than 0.01% by mass of Ti, and less than 0.01% by mass of V, with the balance being Al and unavoidable impurities. In Al-Zr, "0.1 to 1.0% by mass of Fe and Si" has the following meaning. In the case containing both Fe and Si, the combined concentration of Fe and Si is 0.1–1.0% by mass. In the case containing Fe but not Si, the concentration of Fe is 0.1–1.0% by mass. In the case containing Si but not Fe, the concentration of Si is 0.1–1.0% by mass. It should be noted that "not containing" here means, for example, below the detection limit in high-frequency inductively coupled plasma optical emission spectrometry.

[0038] The insulating layer 4 is made of, for example, a fluorine-based resin, an olefin-based resin, or a silicone-based resin. The insulating layer 4 is provided along the entire length of the wire 2, but in this embodiment, a predetermined length of the insulating layer 4 is removed from the end of the wire 2, exposing a portion of the end of the conductor 3.

[0039] Terminal 5 includes a cylindrical portion 6 with a hollow portion 7 and an extension portion 8, which are integrally formed. Terminal 5 may be formed by stamping one end of a tube to create a plate-shaped extension portion 8. Alternatively, terminal 5 may be formed by drilling a hole in one end of a cylindrical base material to create the cylindrical portion 6, and by stamping the other end to create the extension portion 8. The hollow portion 7 has a cylindrical shape with an opening on one side.

[0040] Terminal 5 is made of aluminum, for example. More specifically, pure aluminum or an aluminum alloy is preferred. Pure aluminum is a material composed of Al and unavoidable impurities. For example, electrical pure aluminum (ECAl) can be listed. As an aluminum alloy, Al-Fe-Zr can be listed as an example. Al-Fe-Zr is an aluminum alloy containing 0.01 to 0.10% by mass of Zr, less than 0.1% by mass of Si, 0.2 to 1.0% by mass of Fe, less than 0.01% by mass of Cu, less than 0.01% by mass of Mn, less than 0.01% by mass of Mg, less than 0.01% by mass of Zn, less than 0.01% by mass of Ti, and less than 0.01% by mass of V, with the balance being Al and unavoidable impurities.

[0041] The cylindrical portion 6 is formed into a cylindrical shape with a circular cross-section, and a hollow portion 7 is formed inside it, allowing the conductor 3, which is exposed at the end of the wire 2, to be inserted. The inner diameter N (mm) of the cylindrical portion 6 is approximately 90% to 95% of the outer diameter of the conductor 3, and the conductor 3, exposed at the end of the wire 2, is inserted through the opening of the hollow portion 7. When inserting the conductor 3 through the opening of the hollow portion 7, if the outer diameter of the conductor 3 is compressed to the same extent as the inner diameter of the cylindrical portion 6 using a strap or the like, damage to the conductor 3 can be reduced, and the conductor 3 can be smoothly inserted into the hollow portion 7. Furthermore, the thickness A (mm) of the cylindrical portion 6 is determined by the ratio of the cross-sectional area of ​​the cylindrical portion 6 corresponding to the uncompressed portion 11 of the terminal 5 when the conductor 3 is inserted into the hollow portion 7 and compressed, to the cross-sectional area of ​​the conductor 3 corresponding to the uncompressed portion 11 of the terminal 5. That is, the cross-sectional area of ​​the cylindrical portion 6 of the non-compression portion 11 of terminal 5 is set to T (mm²). 2 Furthermore, the cross-sectional area of ​​the conductor 3 of the non-compression portion 11 of terminal 5 is set to S (mm²). 2 In the case of (T / S), the ratio is determined by the formula. This ratio is preferably in the range of 1.0 to 3.0. If it is less than 1.0, the thickness A of the cylindrical portion 6 is small, and therefore the cylindrical portion 6 may elongate and break due to compression. If it is greater than 3.0, the cylindrical portion 6 is mainly compressed, and the conductor 5 is not sufficiently compressed, which may result in insufficient mechanical connection. The cross-sectional area T (mm²) of the cylindrical portion 6 corresponding to the uncompressed portion 11 of the terminal 5 is... 2 From T = (((2A+N) / 2) 2 -(N / 2) 2 The thickness A of the cylindrical portion 6 can be calculated by multiplying π by π. As long as the cross-sectional area T of the cylindrical portion 6, which is obtained by the ratio of the cross-sectional area T of the cylindrical portion 6 of the non-compression portion 11 of terminal 5 to the cross-sectional area S of the conductor 3 of the non-compression portion 11 of terminal 5, and the inner diameter N of the cylindrical portion 6 are determined, the thickness A of the cylindrical portion 6 can be derived.

[0042] It should be noted that the surface of terminal 5 and the inner surface of cylindrical portion 6 can also be plated with Sn or Ag. Alternatively, a composite containing conductive particles can be applied to the exposed conductor 3 before insertion into the hollow portion 7. Alternatively, a composite can be applied to or filled into the hollow portion 7 of cylindrical portion 6 before insertion of the exposed conductor 3. For example, a fluorinated oil or silicone oil containing conductive particles composed of Ni-P or Ni-B, Ni, and Zn, or a mixture thereof, can be used as the composite containing conductive particles. Terminal 5 is connected to conductor 3 by compressing the hollow portion 7 (cylindrical portion 6) while conductor 3 is inserted into the hollow portion 7.

[0043] The extension 8 is configured to connect to terminals, bolts, or the like on the external connection side. In this embodiment, the extension 8 is formed in the shape of a plate and is provided with bolt holes 9 for inserting bolts or the like for connecting to external terminals.

[0044] In the terminal wire 1 of this embodiment, three or more compression portions 10 are formed in the cylindrical portion 6 of the terminal 5 along the length of the conductor 3. Here, the case of three compression portions 10 will be described, but the number of compression portions 10 may also be four or more. The portion of the cylindrical portion 6 located between adjacent compression portions 10 is referred to as the non-compression portion 11. The compression portion 10 is the portion compressed by the compression mold 20 (described later), becoming a surface that is substantially flat along its length. The non-compression portion 11 is the portion not pressed by the compression mold 20, and its outer diameter is larger than that of the compression portion 10. Between the compression portion 10 and the non-compression portion 11, a conical portion is formed by deformation caused by the pressing of the compression mold 20, and this conical portion is contained within the non-compression portion 11. Details regarding the compression portion 10 and the non-compression portion 11 will be described later.

[0045] In the compression process, a pair of compression molds 20 with a semi-segmented structure are used. The pair of compression molds 20 are used to apply a predetermined pressure to the cylindrical portion 6 of the terminal 5, causing the compressed portion of the cylindrical portion 6 to compress and deform (plasticly deform). The shape of each compression mold 20 can be, for example, a semi-circular shape, a protruding shape, or a hexagonal shape in cross-sectional view. In this embodiment, there is no particular limitation, but the compression ratio of the conductor 3 is preferably 50% or more and 95% or less. Here, the compression ratio refers to the ratio of the cross-sectional area of ​​the conductor 3 corresponding to the non-compressed portion 11 of the terminal 5 and the cross-sectional area of ​​the conductor 3 corresponding to the compressed portion 10 in a cross section perpendicular to the length direction of the conductor 3 when the terminal 5 with the conductor 3 inserted in the hollow portion 7 is compressed. That is, when the cross-sectional area of ​​the conductor 3 corresponding to the non-compressed portion 11 of the terminal 5 is set as S (mm 2 Furthermore, the cross-sectional area of ​​the conductor 3 corresponding to the compression section 10 is set as D (mm²). 2 In the case of (D / S), it can be calculated using the formula (D / S)×100. If the compression ratio is as described above, the decrease in contact force between conductor 3 and terminal 5 caused by stress relief between conductor 3 and terminal 5 can be suppressed, thus suppressing the increase in the resistance ratio of the terminald wire 1. It should be noted that when multiple metal wires are used as conductor 3, the cross-sectional area S of conductor 3 can be calculated by multiplying the cross-sectional area of ​​a single metal wire by the number of metal wires.

[0046] (Manufacturing method for wires with terminals)

[0047] When manufacturing the terminald wire 1, the first step is to prepare the wire 2 and the terminal 5. At this time, the materials for the conductor 3 and the terminal 5 are selected such that the tensile strength of the material used for the conductor 3 is greater than that of the material used for the terminal 5 (for example, greater than 20 MPa or more). For example, when using ECA1 as the material for the terminal 5, Al-Fe-Zr (tensile strength difference: approximately 24 MPa or more) or Al-Zr (tensile strength difference: approximately 46 MPa or more) can be used as the material for the conductor 3 as materials with greater tensile strength. Furthermore, even when using the same materials for both the conductor 3 and the terminal 5, the tensile strength of the materials can be adjusted according to the heat treatment conditions, processing degree, etc., during the manufacturing process.

[0048] In the preparation process, the insulation layer 4 of the wire 2 is removed by a predetermined length from the end of the wire 2 along its length, exposing a portion of the conductor 3. Then, the exposed portion of the conductor 3 of the wire 2 is inserted into the hollow portion 7 of the cylindrical portion 6 formed in the terminal 5.

[0049] Then, with the conductor 3 inserted into the hollow portion 7, the cylindrical portion 6 of the terminal 5 is compressed three or more times to form three or more compressed portions 10 on the terminal, thereby performing a connection process to connect the terminal 5 to the conductor 3. Here, the case where the cylindrical portion 6 of the terminal 5 is compressed three times to form three compressed portions 10 on the terminal 5 will be described.

[0050] In the connection process, firstly, as Figure 2 As shown in (a), the first compression portion 101 is formed by pressing the cylindrical portion 6 near the end of the extension portion 8 (near the end of the conductor 3) using the compression mold 20. Then, as... Figure 2 As shown in (b), the second compression section 102 is formed by pressing the end of the hollow section 7 in the cylindrical section 6 near the opening side (insulating layer 4 side) with the compression mold 20.

[0051] After that, as Figure 2 As shown in (c), the cylindrical portion 6 is compressed by pressing the compression mold 20 at the midpoint between the first compression portion 101 and the second compression portion 102 to form the third compression portion 103. Thus, the connecting process includes forming a new third compression portion 103 between the already formed adjacent first and second compression portions 101 and 102. Uncompressible portions 11 are formed between the first compression portion 101 and the third compression portion 103, and between the third compression portion 103 and the second compression portion 102, respectively. It should be noted that the case where the second compression portion 102 is formed after the first compression portion 101 is formed has been described here, but the first compression portion 101 can also be formed after the second compression portion 102 is formed, or the first compression portion 101 and the second compression portion 102 can be formed simultaneously.

[0052] The first to third compression portions 101 to 103 are formed by applying a predetermined pressure to the entire circumference of the cylindrical portion 6 using a compression mold 20, thereby compressing and deforming the cylindrical portion 6 (plastic deformation). In this embodiment, the cross-sectional shape of each compression portion 101 to 103, perpendicular to the length direction (axial direction) of the conductor 3, is hexagonal. By forming each compression portion 101 to 103, the terminal 5 can be compressed and connected to the conductor 3, resulting in a terminal wire 1.

[0053] (Details of the compression section 10 and the non-compression section 11)

[0054] Here, the behavior of terminal 5 and conductor 3 during the formation of compression section 10 is investigated. For example... Figure 3 As shown in (a), when the terminal 5 and conductor 3 are pressed using the compression mold 20, both the terminal 5 (cylindrical portion 6) and conductor 3 extend in the length direction due to the effect of the pressing. In this embodiment, the tensile strength of the material used for the terminal 5 is lower than that of the material used for the conductor 3, so the terminal 5 deforms to a greater extent, and the difference in elongation between the terminal 5 and conductor 3 is ΔL.

[0055] like Figure 3 As shown in (b), the state in which the first and second compression portions 101 and 102 are formed is set as the initial state. In this state, if the compression mold 20 presses the middle position of the first and second compression portions 101 and 102, the terminal 5 will elongate by an amount ΔL more than the conductor 3 due to the effect of the pressing. Therefore, a contact force (axial contact force) between the terminal 5 and the conductor 3 is generated in the first and second compression portions 101 and 102, which can reduce the contact resistance between the two.

[0056] Due to the effect of the difference ΔL in the elongation of terminal 5 and conductor 3, the contact force (axial contact force) between terminal 5 and conductor 3 can be increased, and the contact resistance between them can be reduced. Although the contact force between terminal 5 and conductor 3 will decrease over time, in this embodiment, a force that stretches terminal 5 and conductor 3 together, i.e., axial contact force, is applied not only in the radial direction but also in the longitudinal direction (axial direction). This axial contact force supports the relaxation of the radial contact force, suppressing the increase in the resistance value between terminal 5 and conductor 3 caused by changes over time.

[0057] To further increase the contact force (axial contact force) between terminal 5 and conductor 3 and further reduce the contact resistance, it is only necessary to further increase the elongation strain. Regarding the elongation strain ε, if the elongation caused by compression is denoted as ΔL, and the compression interval ( Figure 3 (b) If the interval between adjacent compressed portions 10 in the length direction (i.e., the length of the non-compressed portion 11 along the length direction) is set to L, it can be expressed by the following formula.

[0058] ε=ΔL / L

[0059] Therefore, by increasing the elongation ΔL caused by compression and decreasing the compression interval L, the elongation strain caused by compression can be increased, further increasing the contact force (axial contact force) between terminal 5 and conductor 3, and further reducing the contact resistance between the two.

[0060] To increase the difference ΔL between the elongation of terminal 5 and conductor 3 caused by compression, the length of the compression section 10 along its length direction, i.e., the compression width W, can be set to an appropriate width corresponding to the cross-sectional area of ​​the conductor. The compression width W can be controlled by adjusting the size of the compression mold 20 used, and the compression interval L can be controlled by adjusting the position of each compression section 101 to 103 (the position along the length direction of conductor 3).

[0061] The inventors conducted an experiment to investigate the effects of compression width W and compression interval L. First, the compression load on the compression mold 20 was fixed at 12t, the compression interval L (mm) was fixed at 7mm, and the compression width W (mm) was varied during the experiment. In the experiment, a conductor with a cross-sectional area of ​​50mm² was used. 2 and 250mm 2 The conductor 3 of the wire 2 has a conductor cross-sectional area of ​​50 mm². 2 For the sample, the compression ratio was set to 60%–95%, for a conductor cross-sectional area of ​​250 mm². 2 For the samples, the compression ratio was set to 70%–95%. When using a conductor with a cross-sectional area of ​​50 mm²... 2 In the case of wire 2 (approximately 10mm in diameter), the inner diameter N of the cylindrical portion 6 of terminal 5 is 10.2mm, and the thickness A is 3.0mm, when using a conductor with a cross-sectional area of ​​250mm². 2 In the case of wire 2 (approximately 23.6 mm in diameter), the inner diameter N of the cylindrical portion 6 of terminal 5 is 21.8 mm, and the thickness A is 5.2 mm (in the following experiments, terminals of the same size are used for terminal 5). If the compression width W (mm) increases, the compression ratio of conductor 3 also increases.

[0062] (Determination of the rate of increase in resistivity)

[0063] Next, assuming the extension 8 of the terminald wire 1, which is connected to the conductor 3 by compressing terminal 5, is connected to the terminal on the external connection side by bolts or the like, the aluminum plate 13 is fixed to the extension 8 by bolts (not shown), thereby producing a specimen for high-temperature environmental exposure testing. The following high-temperature environmental exposure test is performed: the high-temperature environmental exposure test specimen is placed as follows... Figure 4The aluminum plate was placed in a constant temperature bath 14 set to 200°C as shown and kept in the atmosphere for 100 hours. Every 10 hours, the plate was removed from the bath for bolt installation and removal. The high-temperature exposure test simulated the electrical test environment. It should be noted that although the case where the aluminum plate is fixed to the lower side of the extension 8 is shown, the same results can be obtained even when it is fixed to the upper side of the extension 8.

[0064] The resistivity ratio before and after the high-temperature environmental exposure test is measured, and the resistivity ratio increase rate is calculated from these resistivity ratios. It should be noted that when the resistivity ratio between conductor 3 and terminal 5 before and after the high-temperature environmental exposure test (after 100 hours) is set as R1 and R2 respectively, the resistivity ratio increase rate (%) can be calculated using the formula ((R2-R1) / R1)×100.

[0065] (Determination of resistivity)

[0066] Here, the resistivity ratio (initial resistivity ratio) R1 of the terminald wire 1 before the high-temperature environmental exposure test is determined by the so-called four-terminal method. Figure 5 The four-terminal method will be explained.

[0067] First, a constant current of 1A is supplied to the entire terminal wire 1, and the resistance value R0 between points P and Q is measured. Here, point P is one end of the cylindrical portion 6 of terminal 5, corresponding to the front end of the inserted conductor 3. Point Q is the part of conductor 3 that does not contact terminal 5. Point S is the other end of the cylindrical portion 6 of terminal 5, the entry point for inserting conductor 3. With the distance between points P and S set as L1, the distance between points Q and S set as L2, and the resistance value per unit length of conductor 3 set as α, the initial resistance ratio R1 (%) can be calculated using the formula {(R0-L2×α) / (L1×α)}×100. The resistance value per unit length of conductor 3 can be measured beforehand, or the resistance value between L2 points can be measured and divided by the length between L2 points to obtain the resistance value per unit length.

[0068] Furthermore, the resistance ratio R2 after the high-temperature environmental exposure test was measured using the same four-terminal method as when measuring the resistance ratio (initial resistance ratio) before the test, after cooling the terminal wire 1 to room temperature. Specifically, a constant current of 1A was supplied to the entire terminal wire 1 after the high-temperature environmental exposure test, and the resistance value R between point P and point Q was measured. The resistance value α per unit length of conductor 3 remained unchanged before and after the high-temperature environmental exposure test and was used as the same value. The resistance ratio R2 (%) can be calculated using the formula {(R-L2×α) / (L1×α)}×100. It should be noted that a resistance meter manufactured by Hioki Electric Co., Ltd. was used to measure the resistance value. The experimental results of the resistance ratio R2 after the high-temperature environmental exposure test (after 100 hours) are as follows: Figure 6 As shown in (a).

[0069] like Figure 6 As shown in (a), the cross-sectional area of ​​conductor 3 is 50 mm². 2 In the samples, it can be seen that the larger the compression width W, the lower the resistivity R2. However, if the compression width W is too large, the resistivity R2 increases, and there exists a compression width W where the resistivity R2 reaches a minimum value. It can be seen that in conductor 3 with a cross-sectional area of ​​250 mm²... 2 In the sample, the larger the compression width W, the lower the resistivity R2.

[0070] Similarly, the cross-sectional area of ​​conductor 3 is 50 mm². 2 The compression width W is fixed at 3mm, and the cross-sectional area of ​​conductor 3 is fixed at 250mm². 2 The compression width W was fixed at 7 mm, and the compression load of the compression mold 20 was fixed at 12 t. The compression interval L was varied, and the resistivity R2 after the high-temperature environmental exposure test was calculated. The experimental results are shown below. Figure 6 (b). The cross-sectional area of ​​conductor 3 is 50 mm². 2 In the samples, it can be seen that the larger the compression interval L, the lower the resistivity R2. However, if the compression interval L is too large, the resistivity R2 increases, and there exists a compression interval L where the resistivity R2 reaches a minimum value. It can be seen that when the cross-sectional area of ​​conductor 3 is 250 mm²... 2 In the sample, the larger the compression interval L, the lower the resistivity R2. Additionally, in... Figure 6 (b) also includes a region where the compression interval L is negative, indicating that the compression sections 10 overlap. Figure 6(c) The overlapping state is shown. The compression width W of the first compression section 101, the second compression section 102, and the third compression section 103 pressed by the compression mold 20 overlaps with a compression interval L. With the distance from the right end of the first compression section 101 to the left end of the second compression section 102 set as WL, the compression interval L can be calculated using L = (WL - 3W) / 2. Here, in the case of the overlapping state of the compression sections 10, the value of the compression interval L is negative.

[0071] Figure 7 (a) is a graph where the horizontal axis represents the compression width W and the vertical axis represents the rate of increase in resistivity. With the compression load of the compression mold 20 fixed at 12t, for a conductor with a cross-sectional area of ​​50mm²... 2 The sample and conductor cross-sectional area are 250 mm². 2 For both samples, the compression interval L was fixed at 7 mm, while the compression width W was varied. The increase rate of resistivity before and after the high-temperature environmental exposure test was calculated. Figure 7 As shown in (a), it can be seen that for both types of samples, the larger the compression width W becomes, the lower the rate of increase in resistivity becomes. However, if the compression width W is too large, the rate of increase in resistivity will increase. There is a compression width W where the rate of increase in resistivity becomes the minimum.

[0072] Figure 7 (b) is a graph where the horizontal axis represents the compression interval L and the vertical axis represents the rate of increase in resistivity. Similarly, with the compression load of the compression mold 20 fixed at (12t), the cross-sectional area of ​​the conductor 3 is 50mm². 2 The compression width W is fixed at 3mm, and the cross-sectional area of ​​conductor 3 is 250mm². 2 With the compression width W fixed at 7 mm, the compression interval L was varied to determine the increase rate of resistivity before and after the high-temperature environmental exposure test.

[0073] like Figure 7 As shown in (b), the cross-sectional area of ​​conductor 3 is 50 mm². 2 The cross-sectional area of ​​the sample and conductor 3 is 250 mm². 2 For the samples, generally speaking, the smaller the compression interval L, the lower the rate of increase in resistivity. However, if the compression interval L is too small, the rate of increase in resistivity increases, and there exists a compression interval L where the rate of increase in resistivity reaches a minimum. Furthermore, in... Figure 7 (b) also includes a region where the compression interval L is negative, indicating that the compression sections 10 are overlapping. Regarding Figure 7 The overlapping state of (b) is also with Figure 6 (c) The same state as the overlapping state shown in the figure. The compression width W of the first compression part 101, the second compression part 102, and the third compression part 103 pressed by the compression mold 20 overlaps with the compression interval L.

[0074] Figure 8 (a) is the cross-sectional area S (mm²) of conductor 3 with the horizontal axis set as the horizontal axis. 2 A graph with the vertical axis set to the compression width W (mm). Additionally, Figure 8 (b) is a graph with the horizontal axis set to the cross-sectional area S (mm²) of conductor 3 and the vertical axis set to the compression interval L (mm). Here, the cross-sectional area of ​​conductor 3 is 38 mm². 2 Above and 500mm 2 Under the following conditions, a compression width W (mm) and compression interval L (mm) were found to satisfy the requirement that the resistivity R2 after high-temperature environmental exposure test is less than 100%. The results show that when the compression width W (mm) satisfies Equation (1) and the compression interval L (mm) satisfies Equation (2), the resistivity R2 after high-temperature environmental exposure test is less than 100%.

[0075] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0076] -1.0≤L≤0.145×S+3.75...(2)

[0077] The region shown in equation (1) is Figure 8 (a) is the slanted portion. Similarly, the region shown in equation (2) is... Figure 8 (b) The slanted portion. For example, in conductor 3, the cross-sectional area S is 50 mm². 2 In this case, the compression width W can be selected from 3mm to 7mm and the compression interval L can be selected from -1mm to 11mm. By using the compression width W and compression interval L within the above range, the resistivity R2 after the high temperature environment exposure test can be less than 100%.

[0078] Furthermore, a suitable compression width W (mm) and compression interval L (mm) were found. This is the case where conditions (1) and (2) below are both met. Compared with the case where the target specifications of compression width W and compression interval L are met after the high-temperature environmental exposure test, the range of options is smaller.

[0079] (1) The resistivity R2 after the high temperature environment exposure test is below 100%.

[0080] (2) The rate of increase in resistivity is less than 20%.

[0081] Figure 9 (a) is the cross-sectional area S (mm²) of conductor 3 with the horizontal axis set as the horizontal axis. 2 A graph with the vertical axis set to the compression width W (mm). Additionally, Figure 9 (b) is the cross-sectional area S (mm²) of conductor 3 with the horizontal axis set as the horizontal axis.2 A graph with the vertical axis set to the compression interval L (mm). Here, the cross-sectional area of ​​conductor 3 is 38mm². 2 Above 500mm 2 Under the following conditions, a compression width W (mm) and compression interval L (mm) were found to meet the two target specifications of (1) the resistivity R2 after the high-temperature environmental exposure test is less than 100% and (2) the resistivity increase rate after the high-temperature environmental test is less than 20%. The results show that when the compression width W (mm) meets the following equation (3) and the compression interval L (mm) meets the following equation (4), the two target specifications of (1) the resistivity R2 after the high-temperature environmental exposure test is less than 100% and (2) the resistivity increase rate before and after the high-temperature environmental exposure test is less than 20% are met.

[0082] 0.01×S+2.5≤W≤0.035×S+4.25...(3)

[0083] -1.0≤L≤0.09×S+4.5...(4)

[0084] The region shown in equation (3) is Figure 9 (a) is the slanted portion. Similarly, the region shown in equation (4) is... Figure 9 (b) The slanted portion. For example, in conductor 3, the cross-sectional area S is 50 mm². 2 In this case, the compression width W can be selected from 3mm to 6mm and the compression interval L can be selected from -1mm to 9mm. By using the compression width W and compression interval L within the above range, the resistivity R2 after the high temperature environment exposure test can be less than 100% and the resistivity increase rate can be less than 20%.

[0085] Based on the above results, by adjusting the compression width W and compression interval L to satisfy equations (1) and (2) to form the compression section 10, it is possible to obtain a terminal wire 1 with a smaller resistance ratio R2 after the high-temperature environment exposure test and meeting the above-mentioned target specifications. More preferably, by adjusting the compression width W and compression interval L to satisfy equations (3) and (4) to form the compression section 10, it is possible to obtain a terminal wire 1 with a smaller resistance ratio R2 and resistance ratio increase rate after the high-temperature environment exposure test and meeting the above-mentioned target specifications.

[0086] That is, the compression width W (mm) and compression interval L (mm) of the terminal wire 1 in this embodiment can be determined by the following formulas (1) and (2) and the cross-sectional area S (mm²) of the conductor 3. 2 It can be expressed by a relational expression.

[0087] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0088] -1.0≤L≤0.145×S+3.75...(2)

[0089] Even within this range, the resistivity increase rate can sometimes exceed 20% depending on the compression width W and compression interval L. To meet the target specifications (1) and (2) above, it is more preferable that the compression width W (mm) and compression interval L (mm) are the following formulas (3) and (4) and the conductor cross-sectional area S (mm²). 2 The relationship between ).

[0090] 0.01×S+2.5≤W≤0.035×S+4.25...(3)

[0091] -1.0≤L≤0.09×S+4.5...(4)

[0092] It should be noted that, for example, if the outer diameter of conductor 3 is small, and the compression width W is too small, it may not meet the target specifications. The conductor cross-sectional area S of conductor 3 can be, for example, 38 mm². 2 Above 500mm 2 the following.

[0093] (The role and effects of the implementation method)

[0094] As explained above, in the terminald wire 1 of this embodiment, the tensile strength of the material used for conductor 3 is greater than the tensile strength of the material used for terminal 5, and terminal 5 has three or more compression portions 10 along the length of conductor 3. The cross-sectional area of ​​conductor 3 is set to S (mm²). 2 When the length of the compression section 10 along the length direction, i.e. the compression width, is set to W (mm), and the length of the non-compression section 11 located between adjacent compression sections 10 along the length direction, i.e. the compression interval, is set to L (mm), the values ​​of the compression width W (mm) and the compression interval L (mm) satisfy the following relationships (1) and (2), respectively.

[0095] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0096] -1.0≤L≤0.145×S+3.75...(2)

[0097] More preferably, the values ​​of compression width W (mm) and compression interval L (mm) satisfy the following relationships (3) and (4), respectively.

[0098] 0.01×S+2.5≤W≤0.035×S+4.25...(3)

[0099] -1.0≤L≤0.09×S+4.5...(4)

[0100] With this configuration, regardless of the size (outer diameter, conductor cross-sectional area) of conductor 3, the contact force (axial contact force) between conductor 3 and terminal 5 can be increased, and the resistance between conductor 3 and terminal 5 can be kept low to ensure sufficient electrical connection of the terminal wire 1.

[0101] (Summary of Implementation Methods)

[0102] Next, the technical ideas grasped from the embodiments described above will be described using reference numerals and the like in the accompanying drawings. However, the symbols and the like in the following description do not limit the constituent elements in the claims to the components specifically shown in the embodiments.

[0103] [1] A terminal wire 1 includes: a wire 2 comprising a conductor 3 and an insulating layer 4 covering the conductor 3; and a terminal 5 having a hollow portion 7 for insertion into the end of the wire 2 where the conductor 3 is exposed, wherein the hollow portion 7 is compressed while the conductor 3 is inserted into the hollow portion 7 to connect with the conductor 3, wherein the tensile strength of the material used for the conductor 3 is greater than the tensile strength of the material used for the terminal 5, and the terminal 5 has three or more compression portions 10 along the length direction of the conductor 3, wherein the cross-sectional area of ​​the conductor 3 is S (mm²). 2 When the length of the compression section 10 along the length direction, i.e. the compression width, is set to W (mm), and the length of the non-compression section 11 located between adjacent compression sections 10 along the length direction, i.e. the compression interval, is set to L (mm), the value of the compression width W and the value of the compression interval L satisfy the following relationships (1) and (2), respectively.

[0104] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0105] -1.0≤L≤0.145×S+3.75...(2)

[0106] [2] As described in [1], the value of the compression width W and the value of the compression interval L satisfy the following equations (3) and (4) respectively.

[0107] 0.01×S+2.5≤W≤0.035×S+4.25...(3)

[0108] -1.0≤L≤0.09×S+4.5...(4)

[0109] [3] As described in [1] or [2], the terminal 5 of the wire 1 is made of aluminum material and the conductor 3 is made of aluminum material with a tensile strength greater than that of the aluminum material used in the terminal 5.

[0110] [4] A method for manufacturing a terminal wire 1, the terminal wire 1 comprising: a wire 2 including a conductor 3 and an insulating layer 4 covering the conductor 3; and a terminal 5 having a hollow portion 7 for insertion into the conductor 3 exposed at the end of the wire 2, wherein the hollow portion 7 is compressed while the conductor 3 is inserted into the hollow portion 7, thereby connecting the terminal wire 1 to the conductor 3; the method for manufacturing the terminal wire 1 comprising: a preparation step of preparing the wire 2 and the terminal 5, wherein the tensile strength of the material used for the conductor 3 is greater than the tensile strength of the material used for the terminal 5; and a connection step of forming three or more compression portions 10 on the terminal 5 by compressing the terminal 5 three or more times while the conductor 3 exposed at the end of the wire 2 is inserted into the hollow portion 7, thereby connecting the terminal 5 to the conductor 3; the connection step comprising forming a new compression portion 10 between adjacent compression portions 10 that have already been formed, and wherein the cross-sectional area of ​​the conductor 3 is set to S (mm²). 2 When the length of the compression section 10 along the length direction, i.e. the compression width, is set to W (mm), and the length of the non-compression section 11 located between adjacent compression sections 10 along the length direction, i.e. the compression interval, is set to L (mm), the compression section 10 is formed in such a way that the value of the compression width W and the value of the compression interval L satisfy the following relationship (1) and (2) respectively.

[0111] 0.01×S+2.5≤W≤0.07×S+3.5...(1)

[0112] -1.0≤L≤0.145×S+3.75...(2)

[0113] The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention as defined in the claims. Furthermore, it should be noted that a combination of all the features described in the embodiments is not necessarily necessary for solving the problem of the invention. In addition, the present invention can be implemented with appropriate modifications without departing from its spirit.

Claims

1. A terminal-equipped electric wire, comprising: an electric wire including a conductor and an insulating layer covering the conductor; and a terminal having a hollow portion for insertion of the conductor exposed at an end portion of the electric wire, the terminal being connected to the conductor by compressing the hollow portion with the conductor inserted therein, the material used for the conductor having a tensile strength greater than the material used for the terminal, the terminal having three or more compression portions in a length direction of the conductor, in a case where a cross-sectional area of the conductor is set as S, a length of the compression portion in the length direction, that is, a compression width, is set as W, and a length of a non-compression portion between adjacent compression portions in the length direction, that is, a compression interval, is set as L, the value of the compression width W and the value of the compression interval L respectively satisfy the following relational expressions (1), (2), (3), (4), 0.01 x S + 2.5 ≤ W ≤ 0.07 x S + 3.5 (1) -1.0 ≤ L ≤ 0.145 x S + 3.75 (2) 0.01 x S + 2.5 ≤ W ≤ 0.035 x S + 4.25 (3) -1.0 ≤ L ≤ 0.09 x S + 4.5 (4) 2. The terminal-equipped electric wire according to claim 1, wherein the terminal is composed of an aluminum material, and the conductor is composed of an aluminum material having a greater tensile strength than the aluminum material used for the terminal.

3. A method of manufacturing a terminal-equipped electric wire, the terminal-equipped electric wire comprising: an electric wire including a conductor and an insulating layer covering the conductor; and a terminal having a hollow portion for insertion of the conductor exposed at an end portion of the electric wire, the terminal being connected to the conductor by compressing the hollow portion with the conductor inserted therein, the method of manufacturing the terminal-equipped electric wire comprising: a preparation step of preparing the electric wire and the terminal, the material used for the conductor having a tensile strength greater than the material used for the terminal; and a connection step of connecting the terminal to the conductor by compressing the terminal three or more times to form three or more compression portions in the terminal in a state where the conductor exposed at the end portion of the electric wire is inserted into the hollow portion, the connection step including a step of forming a new compression portion between adjacent compression portions that have already been formed, and in a case where a cross-sectional area of the conductor is set as S, a length of the compression portion in the length direction, that is, a compression width, is set as W, and a length of a non-compression portion between adjacent compression portions in the length direction, that is, a compression interval, is set as L, the compression portions are formed in a manner that the value of the compression width W and the value of the compression interval L respectively satisfy the following relational expressions (1), (2), (3), (4), 0.01 x S + 2.5 ≤ W ≤ 0.07 x S + 3.5 (1) -1.0 ≤ L ≤ 0.145 x S + 3.75 (2) 0.01 x S + 2.5 ≤ W ≤ 0.035 x S + 4.25 (3) -1.0 ≤ L ≤ 0.09 x S + 4.5 (4) ​ ​ ​ ​ ​ ​ ​ wherein, The cross-sectional area S of the conductor is in mm 2 The compressed width W and the compressed interval L are in mm. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ wherein The cross-sectional area S of the conductor is in mm 2 The compressed width W and the compressed interval L are in mm.

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