terminal

Abstract

To provide a terminal which suppresses cracking of the terminal and cutting and falling of an electric wire when used under a vibration environment, and has a relatively small temperature rise amount even if energization is repeated for a long time under the vibration environment.SOLUTION: The terminal 1 is made of aluminum or an aluminum alloy and includes the conducting wire-connecting portion 10 and the plate-shaped portion 20 that has the first main surface 21a and the second main surface 21a facing the first main surface 21b and in which the through-hole 22 penetrating the first main surface 21a and the second main surface 21b is formed. An annular portion 20a of the plate-shaped portion 20 defined by the through hole 22 and an imaginary concentric circle R having a diameter that is 1.5 times the hole diameter of the through hole 22 has, in a crystal orientation analysis performed on a first cross-sectional region including a first main surface 21a and a second cross-sectional region including a second main surface 21b out of four cross-sectional regions obtained by dividing a plate thickness of the plate-shaped portion 20 into four equal parts when viewed from a predetermined cross section, a ratio of measurement points having a GAM value in a range of 1 ° or more and less than 3 ° with respect to all measurement points being 70% or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a terminal made of aluminum or an aluminum alloy. [Background technology]

[0002] Copper-based conductors and copper-based terminals are typically used in power distribution cables. In recent years, aluminum-based conductors have been used to reduce weight, and aluminum-based terminals are sometimes used to connect the terminals of aluminum-based conductors. By fastening an aluminum-based conductor cable with aluminum-based terminals, in which aluminum-based terminals are attached to an aluminum-based conductor, to a connecting member using bolts or the like, an electric circuit can be formed and current can flow.

[0003] Of these, Patent Document 1, for example, describes an aluminum-based terminal in which a spring portion formed in a spring shape and a terminal main body portion formed in a predetermined shape from an aluminum-based material separate from the spring portion are joined together to form an integrated unit, and the aluminum-based material of the spring portion has greater tensile strength and less elongation than the terminal main body portion.By adopting such a configuration, it is possible to provide an aluminum-based terminal that is easy to process and has the necessary strength as a spring piece, thereby achieving both easy processability of the terminal and strength of the spring portion.

[0004] Patent Document 2 also describes a steel sheet containing 0.2 to 0.9 mass% Cu, 0.6 to 1.4 mass% Mg, and the balance being Al and unavoidable impurities, with the unavoidable impurities being restricted to 0.8 mass% or less Si, 0.6 mass% or less Fe, 0.15 mass% or less Mn, 0.3 mass% or less Cr, 0.3 mass% or less Zn, 0.1 mass% or less Ti, and 0.15 mass% or less Zr, with a thickness of more than 1.0 mm and less than 3.0 mm, a grain size of 35 to 300 μm, and a conductivity of 50% IA. The document describes an aluminum-based terminal in which a Ni plating film with a thickness of 0.5 to 5.0 μm is formed on the surface of an aluminum alloy plate that is CS or less, and an Sn plating film with a thickness of 1 to 10 μm is further formed on the Ni plating film. By adopting this configuration, it is possible to provide an aluminum-based terminal that can be bolted and crimped with strong stress initially, and that has little strength loss even when left in a temperature environment of 170°C or less for a long period of time, and that has little stress relaxation in the temperature range of 170°C or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-18698 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-183098 Summary of the Invention [Problem to be solved by the invention]

[0006] The fastening parts between the aluminum-based terminals and the connecting members may generate heat due to temperature changes in the aluminum-based terminals caused by repeated current flow, which may cause stress relaxation in the aluminum-based terminals and increase the contact resistance between the aluminum-based terminals and the connecting members, and in the worst case scenario, this may lead to a fire.

[0007] In this regard, the aluminum-based terminal described in Patent Document 1 has a spring portion used in vehicle wire harnesses, and by controlling the tensile strength and elongation of the aluminum-based material of the spring portion, it is possible to obtain workability and also ensure the strength required for the spring piece, thereby achieving both workability for the terminal and strength for the spring portion. However, particularly in a vibrating environment, wear due to vibration and stress relaxation caused by frictional heat associated with vibration increase contact resistance, causing further heat generation when current is applied. Therefore, there was a need to suppress the temperature rise in aluminum-based terminals when current is applied repeatedly over long periods of time, particularly in a vibrating environment.

[0008] Furthermore, the aluminum-based terminal described in Patent Document 2 suppresses the reduction in fastening strength due to creep and stress relaxation even in high-temperature environments of 170°C or less by specifying the material composition (A5000 series) of the crimping portion. However, sufficient consideration has not been given to aspects such as controlling the crystal orientation, and there is room for improvement, particularly in terms of making it less likely for the terminal to crack when placed in a vibrating environment, or for the conductor (electric wire) connected to the terminal to break or fall off, and in suppressing the amount of temperature rise when electricity is repeatedly passed through the terminal for long periods of time in a vibrating environment.

[0009] Therefore, the present invention has been made in consideration of the above problems, and aims to provide a terminal that controls the characteristics of the aluminum-based conductor that makes up the plate-shaped portion, thereby suppressing cracking of the terminal and breakage or disconnection of the electric wire connected to the terminal when used in a vibrating environment, and that exhibits a relatively small amount of temperature rise even when current is repeatedly passed through the terminal for a long period of time in a vibrating environment. [Means for solving the problem]

[0010] The inventors have thoroughly studied the properties of the aluminum-based conductor that constitutes the plate-like portion, and have focused on controlling the crystalline structure of the aluminum-based conductor; more specifically, on controlling the GAM value, which represents the difference in crystal orientation between measurement points included in a first cross-sectional region that includes the first main surface and a second cross-sectional region that includes the second main surface opposite the first main surface, within the annular portion defined by the through hole of the plate-like portion and a virtual concentric circle having a diameter 1.5 times the diameter of the through hole.They have found that by increasing the proportion of measurement points in both the first and second cross-sectional regions where the GAM values ​​are within a specific range, it is possible to suppress cracking of the terminal and breakage or detachment of the electric wire connected to the terminal when used in a vibrating environment, and further that the amount of temperature rise when electricity is repeatedly passed through the terminal for a long period of time in a vibrating environment is relatively small, thereby reducing stress relaxation in the terminal and maintaining low contact resistance, and have completed the present invention.

[0011] That is, the gist of the present invention is as follows. (1) A terminal comprising: a conductor connection portion made of aluminum or an aluminum alloy and connected to a conductor; and a plate-like portion integrally formed with the conductor connection portion, the plate-like portion having a first main surface and a second main surface opposite the first main surface, and a through hole penetrating the first main surface and the second main surface, wherein, in a cross section of the annular portion of the plate-like portion defined by the through hole and imaginary concentric circles having a diameter 1.5 times the diameter of the through hole, when viewed in a cross section cut along an imaginary plane including the central axis of the through hole, the annular portion of the plate-like portion is divided into four cross-sectional regions obtained by dividing the plate-like portion into four equal sections, a first cross-sectional region including the first main surface and a second cross-sectional region including the second main surface, and the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value is in the range of 1° or more and less than 3° is 70% or more of all measurement points in each cross-sectional region. (2) The terminal described in (1) above, wherein in the crystal orientation analysis, the proportion of measurement points in the first cross-sectional area and the second cross-sectional area where the GAM value is in the range of 1° or more and less than 2° is 70% or more of all measurement points in each area. (3) Made of aluminum, the annular portion of the plate-shaped part has a strength of 800N / mm 2 More than 1500N / mm 2 Indentation hardness H in the following range IT The terminal according to (1) or (2) above, (4) Made of aluminum alloy, the annular portion of the plate-shaped part has a resistance of 2100N / mm 2 More than 4200N / mm 2 Indentation hardness H in the following range IT The terminal according to any one of (1) to (3) above, having: (5) A terminal according to any one of (1) to (4) above, having one or more surface treatment layers selected from the group consisting of a Zn layer, a Sn layer, a Ni layer, a Ni-P layer, and a Cu layer on at least a portion of one or both of the first main surface and the second main surface. [Effects of the Invention]

[0012] According to the present invention, the characteristics of the aluminum-based conductor that constitutes the plate-shaped portion can be controlled, thereby making it possible to provide a terminal that is capable of suppressing cracking of the terminal and breakage or disconnection of the electric wire connected to the terminal when used in a vibrating environment, and that exhibits a relatively small temperature rise even when current is repeatedly passed through the terminal for a long period of time in a vibrating environment. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a perspective view showing an example of the configuration of a terminal according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the terminal of FIG. 1 taken along an imaginary plane P including the central axis of the through hole. [Figure 3] FIG. 3 is a perspective view showing an example of a terminal-attached electric wire in which the terminal according to the embodiment of the present invention is attached to the tip end of the electric wire by crimping and integrally formed. [Figure 4] 4(a) and 4(b) are schematic diagrams showing the relationship between the orientation of the main surface of the plate-shaped part of the terminal and the vibration directions V1 and V2 when a vibration test is performed on a terminal-attached wire in each of two mutually perpendicular vibration directions V1 and V2. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, preferred embodiments of the terminal of the present invention will be described in detail.

[0015] Fig. 1 is a perspective view showing an example of the configuration of a terminal according to an embodiment of the present invention. Fig. 2 is a cross-sectional view of the terminal of Fig. 1 cut along an imaginary plane P including the central axis of the through hole. Fig. 3 is a perspective view showing an example of a terminal-attached electric wire formed by crimping a terminal according to an embodiment of the present invention onto the tip end of an electric wire to form an integral structure. For convenience, the surface treatment layer 24 is omitted from Fig. 2.

[0016] The terminal 1 is made of aluminum or an aluminum alloy and includes a conductor connection portion 10 for connection to a conductor wire, and a plate-like portion 20 formed integrally with the conductor connection portion 10, the plate-like portion 20 having a first main surface 21a and a second main surface 21b opposite to the first main surface 21a, and having a through hole 22 penetrating the first main surface 21a and the second main surface 21b. An annular portion 20a of the plate-like portion 20 defined by the through hole 22 and an imaginary concentric circle R having a diameter 1.5 times the diameter of the through hole 22 is located at the center of the through hole 22. When viewed in a cross section cut by a virtual plane P including the axis C, the thickness of the plate-shaped portion 20 is divided into four equal parts. In a crystal orientation analysis performed by electron backscatter diffraction (EBSD) on a first cross-sectional region 23a including the first main surface 21a and a second cross-sectional region 23b including the second main surface 21b, the proportion of measurement points in the first cross-sectional region 23a and the second cross-sectional region 23b where the GAM value is in the range of 1° or more and less than 3° is 70% or more of all measurement points in each region.

[0017] When evaluating the strain distribution in the annular portion 20a of the plate-like portion 20, the inventors focused on the GAM value, which is the average of the misorientation values ​​between all adjacent measurement points, as a numerical value representing the overall strain in the annular portion 20a. In this case, the inventors discovered that by setting the ratio of the number of measurement points in the annular portion 20a of the plate-like portion 20 of the terminal 1, where the GAM value, which is the average of the misorientation values ​​between all adjacent measurement points, is in the range of 1° or more and less than 3°, to at least 70% of all measurement points, it is possible to suppress cracking of the terminal and breakage or disconnection of the electric wire connected to the terminal when used in a vibrating environment, and to relatively reduce the amount of temperature rise when electricity is repeatedly applied for a long period of time, not only in an environment without vibration but also in a vibrating environment.

[0018] A connecting member (not shown) such as a terminal block is connected adjacent to the first main surface 21a or the second main surface 21b of the plate-like portion 20 of the terminal 1, and a fastening member (not shown) is provided so as to sandwich the plate-like portion 20 and the connecting member. For example, the terminal 1 can be connected by placing the connecting member adjacent to the plate-like portion 20 of the terminal 1 and inserting a fastening member such as a bolt through the through hole 22 to fasten the terminal 1 and the connecting member together with the fastening member so as to sandwich them.

[0019] When connecting the terminal 1 to a connecting member, it is desirable to ensure a sufficient contact area at the portion of the plate-like portion 20 that comes into contact with the connecting member to reduce contact resistance. There are various contact configurations for fastening the terminal 1 to a connecting member, such as a terminal block. One example of a configuration with a small contact area is inserting a fastening member, such as a bolt, through the through hole 22 and fastening the terminal 1 to the connecting member with a specified torque. In this configuration, the terminal 1 and the connecting member are connected with high contact pressure at the portion of the plate-like portion 20 where the washer surrounding the through hole 22 makes contact, thereby reducing contact resistance. However, when the terminal 1 is placed in a vibrating environment while connected to the connecting member, wear due to contact vibrations and stress relaxation in the terminal 1 due to temperature changes caused by frictional heat occur, reducing the contact pressure between the terminal 1 and the connecting member. As a result, the contact area decreases and the contact resistance increases due to the formation of an oxide film, making the fastening portion between the terminal 1 and the connecting member more susceptible to heat generation. The plate-shaped portion 20 of the terminal 1 is generally formed by forging or the like, and such plate-shaped portion 20 often has large surface distortions and is in a hard state, so that stress relaxation is likely to occur due to the temperature rise caused by repeated current flow, especially in a vibrating environment.

[0020] In this regard, in the present invention, by optimizing the manufacturing conditions of the plate-like portion 20 of the terminal 1, the proportion of measurement points in the first cross-sectional region 23a and the second cross-sectional region 23b, which are regions near the surfaces (first principal surface 21a and second principal surface 21b), where the GAM value is in the range of 1° to 3° is adjusted to 70% or more of all measurement points. This reduces the distortion of the surface of the terminal 1 and adjusts it to within an appropriate range. This reduces the temperature rise and the accompanying stress relaxation when electricity is repeatedly applied for a long period of time, not only in a vibration-free environment but also in a vibration environment. Therefore, it is possible to provide a terminal that is less likely to crack or the wire to break or fall off when used in a vibration environment, and that experiences a relatively small temperature rise even when electricity is repeatedly applied for a long period of time in a vibration environment.

[0021] As shown in FIG. 1, the terminal 1 includes a conductor connection portion 10 and a plate-shaped portion 20. The terminal 1 is formed from an aluminum-based material including aluminum (pure aluminum) and aluminum alloys. The aluminum alloy may contain, in addition to aluminum, one or more elements selected from the group consisting of Ti, B, V, Fe, Si, Cu, Mn, Mg, and Zn. Examples of such aluminum-based materials include pure aluminum A1050 and A1070, and aluminum alloy A5052.

[0022] The conductor connection portion 10 of the terminal 1 is configured to connect to a conductor 51, for example, as shown in Fig. 3. Here, the conductor 51 is composed of at least one or more elemental wires 51a, for example, as shown in Fig. 3. The conductor 51 may be a stranded wire in which a plurality of elemental wires 51a are twisted together as shown in Fig. 3, a bundled wire in which a plurality of elemental wires 51a are bundled, or a single elemental wire 51a. The conductor 51 and the elemental wire 51a are preferably made of an aluminum-based material including pure aluminum and an aluminum alloy, or a copper-based material including pure copper and a copper alloy, and more preferably made of an aluminum-based material.

[0023] An insulating coating 52 may be provided on the outer periphery of the portion of the conductor 51 that is not connected to the terminal 1. Furthermore, a sheath 53 may be provided on the outer periphery of the insulating coating 52.

[0024] In Figure 3, at one end of an electric wire 50 having a conductor 51, an insulating coating portion 52, and a sheath 53, the insulating coating portion 52 covering the outer periphery of the conductor 51 and the sheath 53 covering the outer periphery of the insulating coating portion 52 are stripped from the electric wire 50, exposing the conductor 51.

[0025] As shown in Fig. 3, one end of the terminal 1 is provided with a tubular conductor connection portion 10 into which the conductor 51 exposed at one end of the electric wire 50 is inserted. When the conductor connection portion 10 of the terminal 1 is crimped with the conductor 51 inserted into it, a crimped portion 11 is formed, and an electric wire with a terminal is obtained. The conductor connection portion 10 is crimped to the conductor 51 via the crimped portion 11, and is electrically connected to the conductor 51. At the crimped portion 11, the conductor connection portion 10 of the terminal 1 is crimped to the conductor 51 of the electric wire 50.

[0026] Here, an example is shown in which the conductor connection part 10 has a closed tubular shape, but the shape of the conductor connection part 10 is not limited as long as the conductor connection part 10 can be crimped to the conductor 51. The conductor connection part 10 may have, for example, an open shape.

[0027] On the other hand, as shown in FIGS. 1 and 3 , a plate-shaped portion 20 is provided on the other end side of the terminal 1. The plate-shaped portion 20 is formed integrally with the conductor connection portion 10 and has a first main surface 21a and a second main surface 21b opposite the first main surface 21a. A through-hole 22 is formed through the first main surface 21a and the second main surface 21b. This allows a fastening member such as a bolt (not shown) to be inserted through the through-hole 22, making it easier to mechanically and electrically connect the plate-shaped portion 20 of the terminal 1 to a connecting member. Here, from the viewpoint of facilitating insertion of a cylindrical fastening member through the through-hole 22, it is preferable that the through-hole 22 be circular. Note that the connecting member to which the terminal 1 is connected may include a terminal block or the like as well as the plate-shaped portion of another terminal (not shown).

[0028] As shown in FIG. 2, when the terminal 1 is viewed in a cross section cut by an imaginary plane P including the central axis C of the through hole 22, the annular portion 20a of the plate-like portion 20 defined by the through hole 22 and an imaginary concentric circle R having a diameter 1.5 times the diameter of the through hole 22 has a crystal orientation analysis by electron backscatter diffraction (EBSD) performed on a first cross-sectional region 23a including the first main surface 21a and a second cross-sectional region 23b including the second main surface 21b among four cross-sectional regions obtained by dividing the thickness of the plate-like portion 20 into four equal parts. In this analysis, the proportion of measurement points in the first cross-sectional region 23a and the second cross-sectional region 23b where the GAM value is in the range of 1° or more and less than 3° is 70% or more of all measurement points. 2, the four cross-sectional regions obtained from the annular portion 20a of the plate-shaped portion 20 are vertically defined by lines R1 and R2 perpendicular to the first and second main surfaces 21a and 21b, including an imaginary concentric circle R having a diameter 1.5 times the diameter of the through-hole 22, and horizontally defined by lines S1 to S3 parallel to the first and second main surfaces 21a and 21b, which divide the thickness of the plate-shaped portion into four equal parts. Of the four cross-sectional regions horizontally defined by the lines S1 to S3 dividing the thickness into four equal parts, the first cross-sectional region 23a including the first main surface 21a and the second cross-sectional region 23b including the second main surface 21b are regions in which internal stress occurs due to processes such as forging and polishing performed to form the plate-shaped portion 20. Therefore, it is desirable to remove this internal stress and keep distortion within an appropriate range. Therefore, by adjusting the proportion of measurement points in the first cross-sectional region 23a and the second cross-sectional region 23b where the GAM value is in the range of 1° or more and less than 3° to 70% or more of all measurement points, distortion in these regions, which are often in contact with connecting members and washers, is reduced, thereby reducing the temperature rise when current is repeatedly applied for a long period of time in a vibration environment and when current is repeatedly applied for a long period of time in an environment without vibration, and also suppressing the accompanying stress relaxation.In addition, even if stress relaxation occurs due to frictional heat caused by vibration and temperature rise during current application, it is possible to maintain low contact resistance with the connecting members.

[0029] In particular, from the viewpoint of further reducing the amount of temperature rise when current is repeatedly applied for a long period of time in a vibration environment or when current is repeatedly applied for a long period of time in an environment without vibration, in the crystal orientation analysis using the above-mentioned electron backscatter diffraction (EBSD) method, it is preferable that the proportion of measurement points in the first cross-sectional region 23a and the second cross-sectional region 23b where the GAM value is in the range of 1° or more and less than 2° is 70% or more of all measurement points in each region.

[0030] The "GAM value" in this specification can be obtained, for example, from crystal orientation analysis data obtained by continuously measuring crystal orientation data using an EBSD detector (OIM5.0 HIKARI, manufactured by TSL) attached to a high-resolution scanning analytical electron microscope (JSM-7001FA, manufactured by JEOL Ltd.) and then calculating (processing) the measured crystal orientation data using analysis software (OIM Analysis, manufactured by TSL Solutions). "EBSD" stands for Electron Backscatter Diffraction and is a crystal orientation analysis technique that utilizes backscattered electron Kikuchi diffraction, which occurs when a copper-based wire sample is irradiated with an electron beam within a scanning electron microscope (SEM). "OIM Analysis" is software that analyzes data measured by EBSD. The measurement targets are at least one location in the first cross-sectional area 23a and one location in the second cross-sectional area 23b of the surface of the terminal 1, where the plate-shaped portion 20 is embedded in resin and the cross section perpendicular to the extension direction of the plate-shaped portion 20 is mirror-finished by electrolytic polishing. The measurement targets can each measure 800 μm long and 800 μm wide. Measurements can be performed with a step size of 0.1 μm, for example. That is, measurement points in the measurement area are set every 0.1 μm, for example. From these measurement points, measurement points with a reliability index (CI) of 0.1 or higher are selected as measurement points, and the GAM value at each measurement point can be calculated using the Map-Kernel Average Misorientation analysis software.

[0031] Here, the CI value is a value used as an index for indexing a crystal orientation analysis pattern obtained by the EBSD method and for evaluating whether the calculated crystal orientation is correct. In other words, the CI value is a value that reflects the reliability of the crystal orientation measured by the EBSD method in a cross section perpendicular to the extension direction of the plate-shaped portion 20. This CI value can be calculated from the Map-Confidence Index of the analysis software (OIM Analysis, manufactured by TSL) by analyzing the crystal orientation data obtained in the cross section by the EBSD detector as described above.

[0032] When the terminal 1 is made of aluminum (pure aluminum) such as A1050 or A1070, the annular portion 20a of the plate-like portion 20 has a resistance of 800 N / mm 2 More than 1500N / mm 2 Indentation hardness H in the following range IT Here, it is preferable that the indentation hardness H IT is 800N / mm 2 If the indentation hardness H of the annular portion 20a of the plate-like portion 20 is less than 1 / 2, the plate-like portion 20 of the terminal 1 will be too soft and weak, which may cause plastic deformation or fracture in the vicinity of the through-hole 22 of the plate-like portion 20 where the load due to fastening is concentrated during or after fastening of the electric wire to the terminal 1. As a result, it may become difficult to perform the installation using the terminal 1. On the other hand, if the indentation hardness H of the annular portion 20a of the plate-like portion 20 is less than 1 / 2, the plate-like portion 20 of the terminal 1 will be too soft and weak. IT is 1500N / mm 2 If the indentation hardness H is larger than 1000 kJ / s, the stress relaxation of the plate-shaped portion 20 of the terminal 1 due to the temperature rise increases. IT is 800N / mm 2 More than 1500N / mm 2 Compared to the case where the temperature is within the range below, there is a possibility that the temperature rise will be even greater when electricity is repeatedly applied in a vibrating environment.

[0033] Furthermore, when the terminal 1 is made of an aluminum alloy such as A5052, the annular portion 20a of the plate-like portion 20 has a resistance of 2100 N / mm 2 More than 4200N / mm 2Indentation hardness H in the following range IT Here, it is preferable that the indentation hardness H IT is 2100N / mm 2 If the indentation hardness H of the annular portion 20a of the plate-like portion 20 is less than 1 / 2, the plate-like portion 20 of the terminal 1 will be too soft and weak, which may cause plastic deformation or fracture in the vicinity of the through-hole 22 of the plate-like portion 20 where the load due to fastening is concentrated during or after fastening of the electric wire to the terminal 1. As a result, it may become difficult to perform the installation using the terminal 1. On the other hand, if the indentation hardness H of the annular portion 20a of the plate-like portion 20 is less than 1 / 2, the plate-like portion 20 of the terminal 1 will be too soft and weak. IT is 4200N / mm 2 If the indentation hardness H is larger than 1000 kJ / s, the stress relaxation of the plate-shaped portion 20 of the terminal 1 due to the temperature rise increases. IT is 2100N / mm 2 More than 4200N / mm 2 Compared to the case where the temperature is within the range below, there is a possibility that the temperature rise will be even greater when electricity is repeatedly applied in a vibrating environment.

[0034] Indentation hardness H of the annular portion 20a IT can be the indentation hardness of a portion of at least one of the first main surface 21a and the second main surface 21b located in the annular portion 20a. In this case, it is preferable that the indentation hardness of the portion of at least one of the first main surface 21a and the second main surface 21b located in the annular portion 20a be within the above-mentioned range.

[0035] Indentation hardness H IT can be measured using a nanoindenter (microindentation hardness tester) or the like in accordance with, for example, ISO14577-1:2002. At this time, the test temperature is set to 25°C, the load (test force) when the diamond indenter is pressed into the annular portion 20a of the plate-like portion 20, which is the test piece, is set to 0.01 N, and the pressing time of the indenter is set to 10 seconds. The measurement is performed five times while changing the measurement location in the annular portion 20a of the plate-like portion 20, and the average of the measured values ​​is taken as the indentation hardness H IT The measurement results can be as follows.

[0036] The terminal 1 preferably has one or more surface treatment layers 24 selected from the group consisting of Zn, Sn, Ni, Ni-P, and Cu on at least a portion of one or both of the first and second main surfaces 21a and 21b of the plate-shaped portion 20. Examples of the surface treatment layer 24 include, but are not limited to, a plating layer. In particular, a surface treatment layer 24 made of Sn is commonly used for electrical contacts. Because of its softness, it can easily destroy oxide films, thereby reducing contact resistance. Furthermore, a surface treatment layer 24 made of Ni or Ni-P is a hard material, thereby improving durability. Furthermore, a surface treatment layer 24 made of Cu exhibits intermediate properties between a Sn plating layer and a Ni plating layer, providing a good balance between electrical resistivity and durability. Thus, the constituent elements of the surface treatment layer 24 can be appropriately selected depending on the application of the terminal 1.

[0037] The terminal 1 can be suitably used as a wire connecting member used when connecting electric wires to each other or as a terminal connecting member used when connecting an electric wire to an external electronic device. That is, the plate-shaped portion 20 of the terminal 1 may be electrically connected to another electric wire with a terminal or to a connection terminal provided on a connected portion of the external electronic device. In particular, even when the terminal 1 is placed in a vibration environment, the terminal 1 and the conductor connected to the terminal 1 are unlikely to be damaged. Therefore, a wire connecting member or terminal connecting member made of the terminal 1 can be suitably used even in a vibration environment, and can be suitably used, for example, inside a distribution board installed near equipment that generates vibration, such as a machine tool, a blower, a pump, a motor, or an overhead crane.

[0038] Next, a method for manufacturing the terminal 1 will be described.

[0039] First, in the first forging step, when a closed-type terminal 1 is manufactured using a round bar made of an aluminum-based material, the center of the cross section perpendicular to the extension direction of the round bar is compressed by forging to form the conductor connection portion 10, and then the end opposite the conductor connection portion 10 is placed in a mold and compressed by forging to form the plate-shaped portion 20. When a closed-type terminal 1 is manufactured using a pipe material made of an aluminum-based material, the middle portion along the extension direction of the pipe material may be compressed by forging to form the conductor connection portion 10 at a portion including one end, and the opposite end may be compressed by forging to form the plate-shaped portion 20. When an open-type or closed-type terminal 1 is manufactured using a plate material made of an aluminum-based material, the conductor connection portion 10 may be formed by forging to form a portion including one end of the plate material, and the opposite end may be compressed by forging to form the plate-shaped portion 20. In either case, the compression rate of the compression process used to form the plate-shaped portion 20 is preferably in the range of 30% to 50%. In particular, by setting the processing rate in the first forging step to 30% or more, the mechanical strength of the terminal 1 is increased, making it easier to obtain the mechanical strength required to fasten the terminal 1 with a bolt, etc. On the other hand, by setting the processing rate in the first forging step to 50% or less, defects such as cracks can be made less likely to occur during processing to obtain the terminal 1.

[0040] After the first forging step, a first heat treatment step is performed. The first heat treatment step is performed to reduce the deformation resistance of the plate-shaped portion 20 work-hardened by the first forging step and to remove internal stresses generated during the first forging step, thereby adjusting the GAM values ​​in the first cross-sectional region and the second cross-sectional region. The first heat treatment step is performed at a temperature range of 300°C to 450°C for a long period of time of at least one hour, preferably at a temperature range of 300°C to 450°C for a period of at least one hour to three hours. Here, by performing the first heat treatment step for at least one hour, the internal stresses generated during the first forging step can be removed, resulting in the plate-shaped portion 20 being in a state with minimal distortion.

[0041] After the first heat treatment step, a second forging step is performed. In the second forging step, the plate-shaped portion 20 is placed in a die and further compressed by forging. The compression ratio in the second forging step is preferably in the range of 30% to 50%. In particular, by setting the compression ratio in the second forging step to 30% or more, the mechanical strength of the terminal 1 is increased, making it easier to obtain the mechanical strength required for fastening the terminal 1 with a bolt or the like. On the other hand, by setting the compression ratio in the second forging step to 50% or less, defects such as cracks are less likely to occur during processing to obtain the terminal 1. Note that the second forging step in the present invention is distinguished from the first forging step, which is performed before the first heat treatment step, in that it is performed after the first heat treatment step.

[0042] The second heat treatment process, which is performed after the second forging process, is performed to remove internal stresses generated during the first and second forging processes performed on the plate-shaped portion 20 and adjust the GAM values ​​in the first and second cross-sectional regions. From the perspective of removing internal stresses generated in the plate-shaped portion 20, the second heat treatment process is performed at a temperature ranging from 300°C to 450°C for a long period of time of at least two hours, preferably at a temperature ranging from 300°C to 450°C for a period of time ranging from 2 hours to 4 hours. The second heat treatment process may also be performed at the same temperature range and for the same time as the first heat treatment process. By performing the second heat treatment process for at least two hours, internal stresses generated during the first and second forging processes are removed, reducing distortion in the plate-shaped portion 20 and minimizing temperature rise even when current is repeatedly applied for a long period of time in a vibrating environment. The second heat treatment step in the present invention is performed after the second forging step, and is therefore distinguishable from the first heat treatment step which is performed before the second forging step.

[0043] In particular, from the viewpoint of further increasing the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value is in the range of 1° or more and less than 2°, and further reducing the amount of temperature rise when current is repeatedly applied over a long period of time, it is preferable to carry out both the first heat treatment step and the second heat treatment step in a temperature range of 350°C or more and 450°C or less.

[0044] After the second heat treatment step, a polishing step is performed in which the first main surface 21a and the second main surface 21b of the plate-shaped portion 20 are polished by sandblasting. This makes the first main surface 21a and the second main surface 21b of the terminal 1 flatter, thereby increasing the contact area with the connecting member connected to the terminal 1 and reducing the contact resistance with the connecting member.

[0045] In the punching step performed after the polishing step, through-holes 22 are formed in the plate-like portion 20 by punching.

[0046] After the punching process, it is preferable to perform a deburring process in which the portions of the through hole 22 that open to the first main surface 21a and the second main surface 21b are chamfered by lathe processing in order to remove burrs around the through hole 22 that were generated in the punching process.

[0047] Thereafter, a third heat treatment step is preferably performed to adjust the hardness of the annular portion 20a of the plate-shaped portion 20. The third heat treatment step can be performed at a temperature range of 300°C to 600°C for a time period ranging from 1 hour to 3 hours. The third heat treatment step may also be performed in the same temperature range and for the same time period as one or both of the first and second heat treatment steps. Here, by performing the third heat treatment step, the indentation hardness H IT can be adjusted to a preferred range. In this specification, the heat treatment steps performed before the polishing step are referred to as the first heat treatment step and the second heat treatment step, and the heat treatment step performed after the polishing step is referred to as the third heat treatment step.

[0048] After the third heat treatment step, if the plate-shaped portion 20 has a surface treatment layer 24, a plating step is performed. As an example, a surface treatment layer consisting of one or more plating layers selected from the group consisting of a Zn layer, a Sn layer, a Ni layer, a Ni-P layer, and a Cu layer may be formed on the surface of the plate-shaped portion 20. In addition, to improve adhesion with the connecting member, a Zn layer may be formed on the surface of the plate-shaped portion 20 by double zincate treatment, an Ni-P plating layer may be formed thereon, a thin Cu plating layer (Cu strike plating layer) may be formed thereon, and an Sn plating layer may be formed on the surface of that.

[0049] In this manner, the terminal 1 of this embodiment can be obtained.

[0050] Next, a method for manufacturing the terminal-fitted electric wire 100 in which the terminal 1 and the electric wire 50 are crimped will be described.

[0051] First, in the compound insertion process, a compound material is applied to the inside of the conductor connection portion 10 to improve adhesion between the conductor connection portion 10 and the conductor 51. The compound material is mainly composed of mineral oil and zinc powder and is used to ensure a good connection between the conductor connection portion 10 and the conductor 51. When the compound material is provided inside the conductor connection portion 10, it plays a role in ensuring good conductivity of the terminal-attached wire 100, destroying the oxide coatings on the conductor connection portion 10 and the conductor 51, and waterproofing the crimped portion 11.

[0052] In the crimping process carried out after the compound insertion process, the conductor 51 is inserted into the conductor connection portion 10, and a crimping tool is used to apply force to the conductor connection portion 10 from one direction to crimp the conductor connection portion 10 and the conductor 51 together, forming the crimped portion 11. The larger the depression of the crimped portion 11, in other words, the greater the pressing force during crimping, the stronger the bond between the conductor connection portion 10 and the conductor 51. In this way, the electric wire with terminal 100 is obtained.

[0053] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, but includes all aspects encompassed by the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention. [Example]

[0054] Next, in order to further clarify the effects of the present invention, examples of the present invention and comparative examples will be described, but the present invention is not limited to these examples of the present invention.

[0055] (Invention Examples 1 to 32, Comparative Examples 1 to 6) The aluminum-based material used was the type of material listed in Tables 1 and 3. In both the inventive examples and comparative examples, a round bar with a diameter of 17 mm was used as the aluminum-based material. In a first forging step, the center of this round bar was compressed to form a wire connection portion, and the end opposite the wire connection portion was placed in a mold and compressed by forging at the processing ratio listed in Tables 1 and 3 to form a plate-like portion. Next, in a first heat treatment step, heat treatment was performed in an atmospheric heating furnace at the temperature and for the time listed in Tables 1 and 3.

[0056] After the first heat treatment step, the plate-shaped portion was placed in a die and subjected to a second forging step in which the plate-shaped portion was compressed by forging at the working ratios shown in Tables 1 and 3, thereby further compressing the plate-shaped portion.

[0057] In Inventive Examples 1 to 32, after the second forging step, a second heat treatment step was performed in an atmospheric heating furnace at the temperature and for the time shown in Tables 1 and 3. On the other hand, in Comparative Examples 1 to 6, the second heat treatment step was not performed.

[0058] Thereafter, a polishing process was carried out in which both main surfaces (first main surface and second main surface) of the plate-like portion were polished by sandblasting using an alumina-silicon carbide abrasive (manufactured by Fuji Manufacturing Co., Ltd., model number: Fuji Random A-30) as abrasive particles. Thereafter, a punching process was carried out in which through-holes 22 with a hole diameter of 11 mm were formed in the plate-like portion by punching using a die having an upper die and a lower die, and then chamfering was carried out by lathe processing.

[0059] Subsequently, in Inventive Examples 7 to 16, 23 to 32 and Comparative Examples 1, 2, 4, and 5, a third heat treatment step was performed in an atmospheric heating furnace at the temperature and for the time shown in Tables 1 and 3. On the other hand, Inventive Examples 1 to 6, 17 to 22 and Comparative Examples 3 and 6 did not perform the third heat treatment step.

[0060] Thereafter, in Inventive Examples 1, 2, 4 to 18, 20 to 32 and Comparative Examples 1 to 6, a Zn layer, a Ni layer, a Cu layer, and a Sn layer were formed in this order over the entire first and second main surfaces of the plate-shaped portion, thereby forming a plating layer with a total thickness of 16 μm as a surface treatment layer on the plate-shaped portion.On the other hand, in Inventive Examples 3 and 19, no surface treatment layer was formed.

[0061] In this manner, terminals of the present invention and comparative examples were obtained.

[0062] [Various measurement and evaluation methods] The terminals according to the present invention and the comparative example were used to carry out the following characteristic evaluations. The evaluation conditions for each characteristic are as follows, and the results are shown in Tables 2 and 4.

[0063] [1] Measurement of the GAM value of the measurement points included in the first cross-sectional area and the second cross-sectional area The GAM values ​​for the measurement points within the first and second cross-sectional regions were obtained by continuously measuring crystal orientation data using an EBSD detector (TSL, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope (JEOL, JSM-7001FA). The measured crystal orientation data was then calculated (processed) using analysis software (TSL Solutions, OIM Analysis). The measurement targets were three locations within the first and second cross-sectional regions on the cross section containing the central axis of the through hole, as seen on the surface of the terminals obtained in the present invention and comparative examples, each embedded in resin and mirror-finished by electrolytic polishing to a cross section perpendicular to the extension direction of the plate-shaped portion. The measurement regions were each 800 μm long x 800 μm wide. Measurements were performed with a step size of 0.1 μm. Among the measurement points in the measurement area, those with a reliability index (CI) of 0.1 or higher were extracted as measurement points, and the analysis software Map-Kernel Average Misorientation was selected to calculate the GAM value at each measurement point.

[0064] Here, the reliability index (CI) was calculated from the Map-Confidence Index of the analysis software (OIM Analysis, manufactured by TSL) by analyzing the crystal orientation data obtained in the cross section by the EBSD detector.

[0065] From the GAM value data obtained in each measurement region, the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 3° to the total number of all measurement points in the first cross-sectional region, and the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 3° to the total number of all measurement points in the second cross-sectional region were calculated, and the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 3° for the first cross-sectional region and the second cross-sectional region with the smaller ratio is shown in Tables 2 and 4. In addition, the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 2° to the total number of all measurement points in the first cross-sectional area, and the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 2° to the total number of all measurement points in the second cross-sectional area were calculated, and the values ​​of the ratio of the number of measurement points with GAM values ​​in the range of 1° or more and less than 2° for the first cross-sectional area and the second cross-sectional area with the smaller ratio are listed in Tables 2 and 4.

[0066] [2] Indentation hardness H of the annular part of the plate IT Indentation hardness H IT The indentation hardness of the annular portion of the plate-shaped portion was measured using an ultra-micro indentation hardness tester ENT-2100 manufactured by Elionix Co., Ltd., for example, in accordance with ISO14577-1:2002. At this time, the test temperature was set to 25°C, the load (test force) when pressing the diamond indenter into the annular portion of the plate-shaped portion, which is the test piece, was set to 0.01 N, and the pressing time of the indenter was set to 10 seconds. The measurement was performed five times while changing the measurement location in the region corresponding to the annular portion of the first main surface and the second main surface of the plate-shaped portion 20, and the average of the measured values ​​was taken as the indentation hardness H IT The measurement results are shown in Tables 2 and 4.

[0067] [3] Vibration test for terminals To evaluate the cracking and characteristic changes of the terminals under vibration, a vibration test was conducted based on the vibration fatigue test described in "JIS C2805 Crimp Terminals for Copper Wire." A terminal 1 was fastened to one end of a 300 mm long electric wire (aluminum-based electric wire) 50 with a bolt 30. The terminal block 3 with the fastened terminal 1 was fixed to a vibration table 4 in the configuration shown in Figures 4(a) and 4(b). The vibration test was conducted with the other end of the electric wire 50 unconnected. The test consisted of eight hours of vibration along a vibration direction V1 (parallel to the thickness direction of the plate-like portion 20, as shown in Figure 4(a)) and eight hours of vibration along a vibration direction V2 (parallel to the main surface of the plate-like portion 20 and perpendicular to the extension direction of the plate-like portion 20, as shown in Figure 4(b)). The vibration test was conducted under vibration conditions of a single amplitude of 1.5 mm and a frequency of 33 Hz. The vibration test alternated between eight hours of vibration along a vibration direction V1 (parallel to the thickness direction of the plate-like portion 20, as shown in Figure 4(a)) and eight hours of vibration along a vibration direction V2 (parallel to the main surface of the plate-like portion 20 and perpendicular to the extension direction of the plate-like portion 20, as shown in Figure 4(b)).

[0068] [4] Evaluation of terminal cracking under vibration environment Regarding cracking of the terminal under a vibration environment, the terminal 1 was visually observed after the vibration test described in [3] above. If no breakage or detachment of the wire 50 from the terminal 1 was observed and no cracks occurred in the terminal 1, the terminal was evaluated as "Good." On the other hand, if the wire 50 was broken or detached or if cracks occurred in the terminal 1, the terminal was evaluated as "Poor." In the present invention examples and comparative examples, "Good" was evaluated as a pass level. The results are shown in Tables 2 and 4.

[0069] [5] Heat cycle test in an environment without vibration To evaluate the temperature rise during repeated current application, a heat cycle test was performed on the terminals 1 obtained in the present invention and comparative examples (which had not been subjected to a vibration test) with reference to the heat cycle test described in "JIS C 2810 General Rules for Electric Wire Connectors for Indoor Wiring - Non-Separable Type." More specifically, for each of the present invention and comparative examples, two aluminum-based electric wires with terminals, each 2 m or longer, were prepared, each with terminals of the same shape attached to both ends of the aluminum-based electric wire. These two aluminum-based electric wires with terminals were connected in series via a terminal block, with their second principal surfaces facing each other. The temperature of the aluminum-based electric wire was measured by making a slit in the insulating coating at the center of the aluminum-based electric wire and inserting a thermocouple so that it contacted the conductor of the aluminum-based electric wire. A thermocouple was also soldered to the plate-shaped portion of the terminal where the two aluminum-based electric wires with terminals were connected, and the temperature of the terminal was measured. At this time, without applying any vibration to the terminal, a current was applied for one hour at a value set so that the temperature of the aluminum-based electric wire would reach 105°C, and then the current was stopped for one hour, which constituted one cycle. The temperature of the terminal one hour after the 25th cycle of current application was compared to the temperature of the terminal one hour after the 500th cycle of current application, and the amount of temperature rise Δθ (°C) of the terminal one hour after the 500th cycle of current application was measured. At this time, the smaller the temperature rise, the better, as it allows for less heat generation in the aluminum-based electric wire with terminal.

[0070] The measured terminal temperature rise Δθ was rated as "A" if it was 2°C or less. A "B" was given if the temperature rise Δθ was greater than 2°C and less than 4°C, and a "C" was given if it was greater than 4°C and less than 6°C. A "D" was given if the temperature rise Δθ was greater than 6°C and less than 8°C, and an "E" was given if it exceeded 8°C. The present invention and comparative examples were rated in descending order of success as "A," "B," "C," "D," and "E," with "A," "B," and "C" being considered pass levels. The results are shown in Tables 2 and 4.

[0071] [6] Heat cycle test under vibration environment Regarding the temperature rise when current is repeatedly applied for a long period of time in a vibration environment, the heat cycle test described in [5] above was carried out on terminal 1 after the vibration test described in [3] above.

[0072] The measured terminal temperature rise Δθ was evaluated as "A" if it was 2°C or less. Furthermore, a temperature rise Δθ between 2°C and 4°C was evaluated as "B." A temperature rise Δθ between 4°C and 6°C was evaluated as "C." A temperature rise Δθ between 6°C and 8°C was evaluated as "D." On the other hand, a temperature rise Δθ exceeding 8°C was evaluated as "E." The examples of the present invention and the comparative examples were evaluated in descending order of success: "A," "B," "C," "D," and "E." Of these, "A," "B," "C," and "D" were evaluated as pass levels. The results are shown in Tables 2 and 4.

[0073] [Table 1]

[0074] [Table 2]

[0075] [Table 3]

[0076] [Table 4]

[0077] As shown in Tables 1 to 4, in Examples 1 to 32 of the present invention, when the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value was in the range of 1° or more and less than 3° was 70% or more of all measurement points, the temperature rise after the heat cycle test was 7°C or less in both an environment without vibration and an environment with vibration. In contrast, in Comparative Examples 1 to 6, the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value was in the range of 1° or more and less than 3° was outside the above range, and the temperature rise after the heat cycle test in an environment with vibration far exceeded 8°C in all cases.

[0078] Furthermore, in Examples 1 to 32 of the present invention, when the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value was in the range of 1° or more and less than 3° was 70% or more of all measurement points, no cracks in the terminals or breakage or detachment of the wires connected to the terminals were observed.

[0079] From these results, it was confirmed that when the proportion of measurement points in the first cross-sectional area and the second cross-sectional area where the GAM value is in the range of 1° or more and less than 3° is within the appropriate range of the present invention, the terminal of the present invention example is less likely to crack when used in a vibrating environment, and the wire connected to the terminal is less likely to break or fall off, and the temperature rise is small even when a heat cycle test is performed in a vibrating environment. [Explanation of symbols]

[0080] 1 terminal 10 Conductor connection 20 Plate-shaped part 20a Annular portion of plate-shaped part 21a 1st main surface 21b 2nd principal surface 22 Through hole 23a 1st cross-sectional area 23b Second cross-sectional area 24 Surface treatment layer 3 Terminal block 4. Shaking table 50 Electric wire 51 Conductor 51a Bare wire 52 Insulation coating 53 Sheath 100 Wires with terminals C Center axis of through hole P is an imaginary plane including the central axis of the through hole R is an imaginary concentric circle with a diameter 1.5 times the diameter of the through-hole R1, R2 A line containing imaginary concentric circles with a diameter 1.5 times the diameter of the through-hole Lines dividing the thickness of plate-shaped parts S1 to S3 into four equal parts V1, V2 vibration direction

Claims

1. Made of aluminum or an aluminum alloy, a conductor connection portion for connecting to the conductor; a plate-like portion integrally formed with the conductor connection portion, having a first main surface and a second main surface opposite to the first main surface, and having a through hole formed therein that penetrates the first main surface and the second main surface; A terminal comprising: A terminal in which, when viewed in a cross section cut along an imaginary plane including the central axis of the through hole, the annular portion of the plate-like portion defined by the through hole and an imaginary concentric circle having a diameter 1.5 times the diameter of the through hole is such that, in a crystal orientation analysis performed by electron backscatter diffraction (EBSD) on a first cross-sectional region including the first main surface and a second cross-sectional region including the second main surface out of four cross-sectional regions obtained by dividing the plate thickness of the plate-like portion into four equal parts, the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value is in the range of 1° or more and less than 3° is 70% or more of all measurement points in each of the first cross-sectional region and the second cross-sectional region.

2. 2. The terminal according to claim 1, wherein in the crystal orientation analysis, the proportion of measurement points in the first cross-sectional region and the second cross-sectional region where the GAM value is in the range of 1° or more and less than 2° is 70% or more of all measurement points in each region.

3. The annular portion of the plate-shaped portion is made of aluminum and has a strength of 800 N / mm ２ More than 1500N / mm ２ Indentation hardness H in the following range ＩＴ The terminal of claim 1 , comprising:

4. The annular portion of the plate-shaped portion is made of an aluminum alloy and has a strength of 2100 N / mm ２ More than 4200N / mm ２ Indentation hardness H in the following range ＩＴ The terminal of claim 1 , comprising:

5. 5. The terminal according to claim 1, wherein at least a portion of one or both of the first main surface and the second main surface has one or more surface treatment layers selected from the group consisting of a Zn layer, a Sn layer, a Ni layer, a Ni—P layer, and a Cu layer.

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