JP7434398B2 - terminal - Google Patents

Description

The present invention relates to a terminal, and particularly to a terminal used for connecting wire ends or connecting wires.

Usually, a copper-based conductor and a copper-based terminal with high electrical conductivity are used for power distribution wires. In recent years, aluminum-based conductors are sometimes used from the viewpoint of weight reduction. Furthermore, aluminum terminals are sometimes used for terminal connections of aluminum conductors. By fastening an aluminum-based conductor cable with an aluminum-based terminal, which is an aluminum-based conductor with an aluminum-based terminal attached thereto, to another connecting member with a bolt or the like, an electric circuit can be created and a current can be caused to flow.

However, if an aluminum conductor cable with an aluminum terminal is fastened to another connecting member with bolts, etc., and a current is repeatedly applied while these are connected, the area around the connecting part of the terminal and other connecting member may change depending on the current. The temperature around the connecting part changes as it generates and radiates heat. At this time, when viewed from a microscopic point of view, the connection between the terminal and other connecting members undergoes repeated thermal expansion and contraction, causing the surface of the terminal to shift, exposing a new contact surface, and oxidizing the exposed portion. Therefore, contact resistance between the terminal and other connecting members increases. Furthermore, since aluminum has a large coefficient of thermal expansion, the change in size due to thermal expansion becomes large, so that the contact resistance between the terminal and other connecting members is more likely to increase. As a result, the contact resistance between the terminal and other connecting members increases and the temperature rises, so it may be necessary to take measures to prevent a fire accident.

Therefore, aluminum-based terminals are known in which a copper-based material is used for the connection portion that connects to other connection members. For example, in Patent Document 1, the opposite ends of the aluminum rods are joined in a recess with a diameter slightly larger than the diameter of the opposite ends of the opposite aluminum rods provided at the opposite ends of the copper terminal battledore part, and both A copper-aluminum terminal is described in which a corrosion-protective material is interposed in a groove formed around the joint.

Utility Model Publication No. 53-85586

The copper-aluminum terminal described in Patent Document 1 is a terminal in which copper and aluminum are joined by friction welding, and the conductor connection part that connects to the aluminum rod (aluminum-based conductor wire) is made of an aluminum-based material, and other materials are used. A copper-based material is used for the terminal battledore portion that connects to the connecting member, and these opposing surfaces are joined by a joining surface.

However, when installing indoor wiring, there is limited space in which to install terminals and route conductors, and it is difficult to pull or bend the conductors after connecting the terminals to other connection members. In some cases, measures may be taken. At this time, the terminals are also subjected to a bending load in the same way as the conductor wires, which may cause cracks to occur at the joints of the terminals and cause them to break. Therefore, there is a need for terminals that can withstand bending during wiring of electric wires.

In this regard, in the copper-aluminum terminal described in Patent Document 1, as is clear from the fact that there is no description of the state of the bonded interface, the conductor is pulled after the terminal is connected to another connecting member. It does not focus on durability when being bent or bent. However, in a terminal in which an Al-based material such as aluminum and a Cu-based material such as copper are joined by friction welding, as described in Patent Document 1, these joints tend to be weak against bending and tension. .

Therefore, an object of the present invention is to provide a terminal in which cracks do not easily occur at the joint where an Al-based material and a Cu-based material are joined.

In order to achieve the above object, the gist of the present invention is as follows.

(1) It has a first connection part made of an Al-based material and connected to a conductive wire, and a second connection part made of a Cu-based material and connected to another conductor member, and the first connection part A first end portion that is a solid portion and a second end portion that is a solid portion of the second connecting portion are joined while facing each other, and the first opposing surface of the first end portion and the second end portion that are the solid portion of the second connecting portion are A terminal in which a bonding surface is formed between the second opposing surfaces of the second end, when viewed in a longitudinal section when cut along the longitudinal direction of the terminal passing through the center position of the bonding surface. , the first connection part is such that the terminal position of a microcrystalline region having an average crystal grain size of 3 μm or less of the Al-based material, which starts from the joint surface, is located at the terminal from the center position of the joint surface. It is defined by a first position separated in the longitudinal direction by a dimension corresponding to 3% of the equivalent circular diameter of the joint surface, and a second position separated by a dimension corresponding to 15% of the circular equivalent diameter of the joint surface. When the microcrystalline region is located in a first region and is divided into a first central region and a first outer peripheral region located around the first central region, the Al system in the first central region A terminal, wherein the ratio of the average crystal grain size of the Al-based material in the first outer peripheral region to the average crystal grain size of the material is in the range of 0.75 or more and 1.25 or less.

(2) The terminal according to (1) above, wherein the first end of the first connecting portion and the second end of the second connecting portion both have a substantially cylindrical shape.

(3) Seen in the longitudinal section, the second connecting portion is located at a fifth point spaced apart from the center position of the joint surface by a dimension corresponding to 3% of the equivalent circle diameter of the joint surface in the longitudinal direction of the terminal. A dimension corresponding to 15% of the equivalent circular diameter of the bonding surface in the longitudinal direction of the terminal, starting from the center position of the bonding surface, relative to the average crystal grain size of the Cu-based material in the second region defined by the position. The ratio of the average crystal grain size of the Cu-based material in the third region defined by the sixth position separated by a distance of 0.01 and the seventh position separated by a dimension corresponding to 20% of the equivalent circle diameter of the bonding surface is 0. The terminal according to (1) or (2) above, which is in the range of 75 or more and 1.25 or less.

(4) When viewed in the longitudinal section, the length dimension of the joining line, which is the line where the joining surface is exposed, is the circle equivalent diameter of the first end of the first connecting part and the length of the joining line, which is the line where the joining surface is exposed. Any one of (1) to (3) above, which is larger than the smaller equivalent circle diameter by 0.6% or more and 21.1% or less among the equivalent circle diameters of the second end. Terminals listed in .

(5) A bonding line that is a line where the bonding surface is exposed when viewed in the longitudinal section; a first outer circumference line that is a line where the outer circumferential surface of the first end of the first connection portion is exposed; and The average angle at the joint end position of the second connecting portion with any one of the second peripheral lines, which is a line on which the peripheral surface of the second end portion is exposed, is 78° or more and 88° or more. The terminal according to any one of (1) to (4) above, wherein the terminal is within a range of .

(6) When viewed in the longitudinal section, the bonding line, which is a line where the bonding surface is exposed, extends in the longitudinal direction to a bonding range of a size equivalent to 2% or more of the equivalent circle diameter of the bonding surface; and any one of (1) to (5) above, wherein at least a part of the bonding range has a range where two or more intersections between a perpendicular line to the longitudinal direction and the bonding line are formed. The terminal described in item 1.

(7) When WDX analysis is performed by scanning along the longitudinal direction of the terminal in the longitudinal section, the detected intensities of Al and Cu are both expressed as an intensity ratio to the sum of the detected intensities of all elements analyzed. The terminal according to any one of (1) to (6) above, wherein the scanning length of the area where the area is 90% or less is 5 μm or less.

According to the present invention, it is possible to provide a terminal in which cracks do not easily occur at the joint where an Al-based material and a Cu-based material are joined.

FIG. 1A is a perspective view of the terminal of the first embodiment. FIG. 1B is a diagram showing a first region, a second region, and a third region of the terminal of the first embodiment, and is a longitudinal cross-sectional view on the virtual plane P of FIG. 1A. FIG. 1C is a diagram showing the first central region and the first outer peripheral region of the terminal of the first embodiment, and is a longitudinal cross-sectional view on the virtual plane P of FIG. 1A. FIG. 2 is a longitudinal sectional view showing the internal structure of the terminal of the second embodiment. FIG. 3 is a vertical cross-sectional view of a main part of a joint surface constituted by a curved surface, showing an example before and after joining, and FIG. 3(a) is a vertical cross-sectional view showing the state before joining. 3(b) is a vertical cross-sectional view showing the state after joining. FIG. 4 is a vertical cross-sectional view of a main part of a joint surface formed by a curved surface, showing another example before and after joining, and FIG. 4(a) is a vertical cross-sectional view showing the state before joining. , FIG. 4(b) is a longitudinal sectional view showing the state after bonding. FIG. 5 is a vertical cross-sectional view of a main part showing another example of a joint surface formed by a curved surface before and after joining, and FIG. 5(a) is a vertical cross-sectional view showing the state before joining. , FIG. 5(b) is a longitudinal cross-sectional view showing the state after bonding. FIG. 6 is a diagram for explaining a method for evaluating three-point bending of a terminal.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments, and various changes can be made without changing the gist of the present invention.

<First embodiment>
FIG. 1A is a perspective view of the terminal of the first embodiment. Moreover, FIG. 1B is a diagram showing the first region, second region, and third region of the terminal of the first embodiment, and is a longitudinal cross-sectional view on the virtual plane P of FIG. 1A. Moreover, FIG. 1C is a diagram showing the first central region and the first outer peripheral region of the terminal of the first embodiment, and is a longitudinal cross-sectional view on the virtual plane P of FIG. 1A.

The terminal 1 has a first connection part 11 made of an Al-based material and connected to the conductor 7, and a second connection part 12 made of a Cu-based material to which another conductor member 8 is connected. The first end 11a, which is a solid part of the first connecting part 11, and the second end 12a, which is a solid part of the second connecting part 12, are joined in a state where they are opposed to each other to form the first end 11a. A terminal 1 in which a bonding surface 3 is formed between a first opposing surface 31 of the second end 12a and a second opposing surface 32 of the second end 12a, the longitudinal direction of the terminal 1 passing through the center position _C0 of the bonding surface 3. When viewed in a longitudinal cross-section taken along the direction , a first position 41 separated by a dimension corresponding to 3% of the circle equivalent diameter D of the joint surface 3 in the longitudinal direction X of the terminal 1, starting from the center position C ₀ of the joint surface 3; The microcrystalline region is located within the first region 51 defined by the second position 42 separated by a dimension corresponding to 15% of the diameter D, and the microcrystalline region is defined by the first central region 61 and around the first central region 61. When partitioning into a first outer circumferential region 62 located at It is in the range of 1.25 or more.

In this terminal 1, there is a region where fine crystal grains of the Al-based material exist around the joint surface 3 of the first connection portion 11 made of the Al-based material with the second connection portion 12 made of the Cu-based material. In the microcrystalline region that is spread out and near the bonding surface 3, the grain size of the Al-based material in the first central region 61 and the grain size of the Al-based material in the first outer peripheral region 62 located around it are the same. , are almost the same size. In this way, by expanding the area where fine crystal grains of the Al-based material exist in and around the bonding surface 3 with the Cu-based material, the Al-based material will resist deformation when the terminal 1 is pulled or bent. The joint portion between the material and the Cu-based material can be made sufficiently durable. If the crystal grain size of the Al-based material is fine and uniform at the joint surface 3 with the Cu-based material and its surroundings, local deformation will occur when the terminal 1 is pulled or bent. This is thought to be because the entire terminal 1 can be gently deformed without causing any deformation.

In addition, in this terminal 1, a first connection part 11 made of an Al-based material and a second connection part 12 made of a Cu-based material are joined at a joint surface 3, and a second connection part 11 made of an Al-based material is joined at a joint surface 3. Since the 2-connection portion 12 is made of a Cu-based material, contact resistance with other conductor members 8 can be reduced.

Therefore, by using this terminal 1, it is possible to provide a terminal 1 in which cracks do not easily occur at the joint where the Al-based material and the Cu-based material are joined.

[About the terminal configuration]
As shown in FIG. 1A, the terminal 1 includes a first connection part 11 made of an Al-based material and connected to the conductor 7, and a second connection part 12 made of a Cu-based material and connected to another conductor member 8. and has.

As the Al-based material constituting the first connection portion 11, pure aluminum or an aluminum alloy can be used. Here, from the viewpoint of increasing the conductivity of the first connecting portion 11, it is preferable to use pure aluminum as the Al-based material. On the other hand, from the viewpoint of increasing the durability strength of the first connecting portion 11, it is preferable to use an aluminum alloy as the Al-based material. Examples of pure aluminum include industrial pure aluminum; for example, in addition to aluminum, it contains 0.3% by weight or less of Fe (iron), 0.1% by weight or less of Si (silicon), and other elements. Those containing 0.1% by weight or less in total can be used. On the other hand, from the viewpoint of not reducing the conductivity of the first connecting portion 11, it is preferable that the aluminum alloy contains few additive elements, such as Fe (iron), Si (silicon), Cu (copper), Mg (magnesium). ), Mn (manganese), Cr (chromium), Zn (zinc), and Ti (titanium) each at 1% by weight or less, and other elements in a total amount of 0.1% by weight or less can be used.

As the Cu-based material constituting the second connection portion 12, pure copper or a copper alloy can be used. Here, from the viewpoint of increasing the conductivity of the second connection portion 12, it is preferable to use pure copper as the Cu-based material. On the other hand, from the viewpoint of increasing the durability strength of the second connecting portion 12, it is preferable to use a copper alloy as the Cu-based material. Examples of pure copper include tough pitch copper and oxygen-free copper, and for example, copper containing other elements in a total amount of 0.1% by weight or less in addition to copper can be used. On the other hand, from the viewpoint of not reducing the conductivity of the second connection part 12, the copper alloy preferably contains few additive elements, such as those containing 1% by weight or less of each of Sn (tin) or Cr (chromium). , brass can be used.

In this terminal 1, as shown in FIG. 1B, the first end portion 11a, which is a solid portion of the first connecting portion 11, and the second end portion 12a, which is a solid portion of the second connecting portion 12, are mutually connected. The joint surface 3 is formed between the first opposing surface 31 of the first end 11a and the second opposing surface 32 of the second end 12a, which are the opposing surfaces at this time. It is formed.

Here, it is preferable that the first opposing surface 31 of the first end 11a and the second opposing surface 32 of the second end 12a both have a substantially circular shape and are arranged substantially concentrically. . In particular, it is more preferable that the first end portion 11a of the first connecting portion 11 and the second end portion 12a of the second connecting portion 12 both have a substantially cylindrical shape. In this way, the first opposing surface 31 and the second opposing surface 32 have a substantially circular shape, and more preferably, the first end 11a and the second end 12a have a substantially cylindrical shape. When the first connecting portion 11 and the second connecting portion 12 are joined, the first end portion 11a and the second end portion 12a are heated evenly, so that crystal grains can be made to exist more uniformly.

It is preferable that the first opposing surface 31 of the first end 11a and the second opposing surface 32 of the second end 12a both have an equivalent circle diameter of 25 mm or less. If the equivalent circle diameter of the first opposing surface 31 and the second opposing surface 32 exceeds 25 mm, cooling after joining the first connecting portion 11 and the second connecting portion 12 is likely to be insufficient, and the joining surface Since the crystal grain size in the vicinity of terminal 3 becomes non-uniform, durability against deformation when the terminal 1 is pulled or bent tends to decrease. Note that the lower limit of the equivalent circle diameters of the first opposing surface 31 and the second opposing surface 32 is not particularly limited, but may be, for example, 7 mm or more.

As shown in FIG. 1B, the first connecting portion 11 has the joining surface 3 as the starting end when viewed in a longitudinal section taken along the longitudinal direction X of the terminal 1 passing through the center position _C0 of the joining surface 3. The terminal position of the microcrystalline region where the average crystal grain size of the Al-based material is 3 μm or less is the circle equivalent diameter D of the joint surface 3 in the longitudinal direction X of the terminal 1, starting from the center position _C0 of the joint surface 3. It is located within a first region 51 defined by a first position 41 separated by a dimension corresponding to 3% of the diameter D of the joint surface 3, and a second position 42 separated by a dimension corresponding to 15% of the equivalent circle diameter D of the joint surface 3. It is configured as follows. This expands the region where fine crystal grains of the Al-based material exist in the range from the bonding surface 3 to the position within the first region 51, so that it is particularly resistant to deformation when the terminal 1 is pulled or bent. The Al-based material near the bonding surface 3, which is softer and less durable than the Cu-based material, can be made sufficiently durable. Such a microstructure in which fine crystal grains of the Al-based material exist in the range from the bonding surface 3 to the inside of the first region 51 can be used, for example, when bonding the first connection portion 11 and the second connection portion 12. It can be obtained by cooling the vicinity of the joint surface 3 with water cooling or the like. On the other hand, if the terminal position of this microcrystalline region is not within the range of 3% or more and 15% or less of the equivalent circular diameter D of the joint surface 3 in the longitudinal direction _X of the terminal 1 starting from the center position C0 of the joint surface 3; , and it is not within the range of more than 15% of the equivalent circle diameter D of the joint surface 3 in the longitudinal direction There is a risk that the terminal 1 may be damaged due to insufficient durability against deformation. Furthermore, if the terminal position of this microcrystalline region is in a range exceeding 15% of the equivalent circle diameter D of the joint surface 3 in the longitudinal direction X, the vicinity of the joint surface 3 is heated more than necessary, and aluminum Since a copper intermetallic compound is generated and the vicinity of the bonding surface 3 becomes brittle, the terminal 1 may not be able to sufficiently withstand deformation when pulled or bent, and the terminal 1 may break. Therefore, the terminal position of this microcrystalline region is in the range of 5% to 12% of the equivalent circular diameter D of the bonding surface 3 in the longitudinal direction X of the terminal 1, starting from the center position _C0 of the bonding surface 3. It is preferable that it is in the range of 6% or more and 10% or less of the equivalent circle diameter D of the joint surface 3.

The terminal position of this microcrystalline region is determined by measuring 105 μm in width using an optical microscope with a magnification of 1000 times with respect to the longitudinal section of the terminal 1 when cut along the longitudinal direction X passing through the center position _C0 of the bonding surface 3. The bonding surface 3 is exposed in the image obtained by taking an image in an observation area of 80 μm vertically, passing through the center position _C0 of the bonding surface 3 and including the center line C along the longitudinal direction X of the terminal 1. When _the average crystal grain size of the Al-based material is measured by dividing the bonding line, which is a line parallel to the longitudinal direction X, into 1% of the equivalent circle diameter D from the center position , among the sections where the average crystal grain size is 3 μm or less, the terminal end position can be in the section farthest from the bonding surface 3. In other words, the longitudinal section is measured by dividing it into sections of 1% from the center position C ₀ in the following manner: divisions exceeding 0% but not more than 1% of the equivalent circle diameter D of the joint surface 3, and divisions exceeding 1% and not more than 2%. Find the average crystal grain size of the Al-based material, and first find the position of the boundary between the section where the average crystal grain size is over 3 μm and the section smaller than that by 1% of the equivalent circle diameter D. This can be the terminal position of the microcrystalline region. For example, the average crystal grain size in a section that is 10% or less of the equivalent circle diameter D of the joint surface 3 is all 3 μm or less, and the average crystal grain size in a section that is more than 10% and 11% or less of the equivalent circle diameter D of the joint surface 3. is 3.5 μm, the end position of this microcrystalline region is 10% of the equivalent circle diameter D of the bonding surface 3.

The equivalent circle diameter D of the bonding surface 3 is determined by polishing the terminal 1 in the longitudinal direction X from the Al-based material side to the Cu-based material side, with the cross section perpendicular to the longitudinal direction X as the polishing surface. Then, the cross-section at the moment when the entire surface of the polished surface is changed to Cu-based material is polished to a mirror surface, photographed with an optical microscope, and the area of the bonding surface 3 is determined by analyzing the obtained image. The diameter of a circle having an area equal to can be defined as the equivalent circle diameter D. Further, if the appearance of the terminal 1 is visually observed and it is clear that the bonding surface 3 is circular, the diameter of the bonding surface 3 may be directly measured with a caliper.

In the first connecting portion 11, microcrystalline regions in which the average crystal grain size of the Al-based material is 3 μm or less are located in the first central region 61 and around the first central region 61, as shown in FIG. 1C. When partitioning into the first outer peripheral region 62, the ratio of the average crystal grain size of the Al-based material in the first outer peripheral region 62 to the average crystal grain size of the Al-based material in the first central region 61 is 0.75 or more. 25 or less. As a result, in the microcrystalline region, the grain size of the Al-based material in the first central region 61 and the grain size of the Al-based material in the first outer peripheral region 62 located around it become approximately the same size. Therefore, when the terminal 1 is pulled or bent, local deformation is less likely to occur, and as a result, the terminal deforms as a whole. It can be made durable enough. On the other hand, if the ratio of the average crystal grain size of the Al-based material in the first peripheral region 62 to the average crystal grain size of the Al-based material in the first central region 61 is less than 0.75 or more than 1.25, Since the crystal grain size in the crystal region becomes non-uniform, the terminal 1 may not be able to withstand enough deformation when being pulled or bent, and the terminal 1 may be destroyed. The ratio of the average crystal grain size of the Al-based material in the first outer peripheral region 62 to the average crystal grain size of the Al-based material in the first central region 61 is preferably in the range of 0.85 or more and 1.15 or less, and 0.90. A range of 1.10 or less is more preferable.

Here, the first central region 61 is set in a region closer to the center of the microcrystalline region of the Al-based material. More specifically, the first central region 61 passes through the center position _C0 of the joint surface 3, is at or near the center line C along the longitudinal direction X of the terminal 1, and is a circle extending from the center line C. It is set in an area surrounded by the third position 43 located on the outer circumferential surface 21 side by a dimension corresponding to 5% (D/20) of the equivalent diameter D. On the other hand, the first outer peripheral region 62 can be set in a region closer to the outer peripheral surface 21 in the microcrystalline region of the Al-based material. More specifically, the first outer circumferential region 62 has a fourth position 44 located on the center line C side by a dimension corresponding to 5% (D/20) of the equivalent circle diameter D from the first outer circumferential line 21a; It is set in the area surrounded by the outer circumferential line 21a.

Here, the average crystal grain size of the Al-based material in the first central region 61 is the first central region of the portion corresponding to the microcrystalline region in the vertical cross-sectional image used to find the end position of the microcrystalline region described above. 61, a line segment that spans 50 grain boundaries is drawn along the longitudinal direction X, and the length of the segment that spans the grain boundaries is divided by 50. If it is not possible to draw a line segment that spans 50 grain boundaries along the center line C, you may use multiple images taken in the same way, or draw multiple line segments on the same image. Good too. Similarly, regarding the average crystal grain size of the Al-based material in the first outer circumferential area 62, the first outer circumferential area when the terminal 1 is cut along the longitudinal direction X so as to pass through the center position _C0 of the joint surface 3. A vertical cross section including 62 was photographed in an observation area of 105 μm in width x 80 μm in height using an optical microscope with a magnification of 1000 times, and a line such that 50 grain boundaries spanned the first outer peripheral region 62 of the part corresponding to the microcrystalline region. It can be determined by drawing a line segment along the longitudinal direction X and dividing the length of the portion of the line segment that straddles the grain boundary by 50.

The conducting wire 7 connected to the first connecting portion 11 is not particularly limited, and may be composed of a single strand, a stranded wire made by twisting a plurality of strands, or a stranded wire made by twisting a plurality of strands. It may be a bundled wire. As an example of the material of the conducting wire 7, an Al-based material including pure aluminum and an aluminum alloy can be mentioned.

As shown in FIG. 1B, the second connecting portion 12 is of the bonding surface 3 when viewed in a longitudinal section taken along the longitudinal direction X of the terminal 1 so as to pass through the center position _C0 of the bonding surface 3. Cu-based material in a second region 52 defined by a center position _C0 and a fifth position 45 separated from the center position C0 by a distance corresponding to 3% of the equivalent circle diameter D of the joint surface 3 in the longitudinal direction X of the terminal 1. a sixth position 46 that is spaced from the center position _C0 of the joint surface 3 in the longitudinal direction X of the terminal 1 by a dimension corresponding to 15% of the equivalent circle diameter D of the joint surface 3, The ratio of the average crystal grain size of the Cu-based material in the third region 53 defined by the seventh position 47 separated by a dimension corresponding to 20% of the equivalent circle diameter D of the joint surface 3 is 0.75 or more and 1. It is preferably in the range of 25 or less. As a result, the average crystal grain of the Cu-based material is formed between the second region 52, which is near the joint surface 3, and the third region 53, which is sufficiently far away from the joint surface 3 and is not affected by the heat during joining. Since the diameters are approximately the same size, the effect of frictional heat near the joint surface 3 is small, making it difficult to form an intermetallic compound between aluminum and copper, making it easier to pull or bend the terminal 1. The bonded portion of the Al-based material and the Cu-based material can be made sufficiently durable against deformation caused by

The second connecting portion 12 includes a plate-like connecting portion 12b at a position separated from the joining surface 3 (in the terminal 1 of FIG. 1, on the other end side in the longitudinal direction X with respect to the joining surface 3). The plate-like connecting portion 12b includes a through hole S, through which a fastening member 9 such as a bolt can be inserted to mechanically and electrically connect to another conductor member 8.

The first connecting portion 11 and the second connecting portion 12 are scanned along the longitudinal direction X of the terminal ₁ in a longitudinal section taken along the longitudinal direction When performing WDX analysis, the scanning length of the region where the detected intensity of Al and Cu is 90% or less as an intensity ratio to the total detected intensity of all analyzed elements is 5 μm or less. It is preferable. As a result, Cu atoms and Al atoms are appropriately diffused in the bonding surface 3, so that the bonding strength between the first connecting portion 11 and the second connecting portion 12 can be further increased. On the other hand, if the scanning length of the region where the detection intensity of Al and Cu is 90% or less exceeds 5 μm, a brittle intermetallic compound of aluminum and copper is generated near the bonding surface 3, and the intermetallic compound is Since cracks tend to form starting from the generated locations, the bonding strength between the first connecting portion 11 and the second connecting portion 12 tends to decrease.

[About the terminal manufacturing method]
Next, a method for manufacturing the terminal 1 will be explained.

First, in the first lathe processing step, lathe processing is performed on the end face of the copper round bar that will become the second connecting portion 12, so that protrusions and grooves, which will be described later, can be formed in the portion that will become the second end portion 12a. This first lathe processing step does not have to be performed in a mode including the second end portion 12a having a substantially cylindrical shape as shown in FIG.

In the friction welding process that is performed after the first lathe processing process, the aluminum round bar that will become the first connection part 11 and the copper round bar that will become the second connection part 12 are placed facing each other while the friction welding device is being heated. The aluminum round rod and the copper round rod are placed in a tool and rotated relative to each other, and the aluminum and copper rods are pressed together to heat them by friction, and then pressed together with a larger upset pressure to join them. In particular, in the terminal 1 of the present invention, the frictional heat at the outer periphery caused by the high circumferential speed of the aluminum round bar and the copper round bar is suppressed, and the coarsening of crystal grains at the outer periphery caused by this is suppressed. In order to suppress this, when heating the aluminum round rod and copper round rod by friction, water is sprayed onto the part where the aluminum round rod and copper round rod come into contact, thereby reducing the outer periphery of the part to be joined by friction welding. Perform friction welding while cooling with water. Thereby, the crystal grain size at the bonding surface 3 can be controlled to be substantially uniform.

In the second lathe process performed after the friction welding process, the end of the first connection part 11 on the side where the second connection part 12 is not joined is cut by lathe process so that it becomes hollow, and the conductive wire 7 A conductive wire connecting portion 11b is formed to connect the ends of the wire by crimping.

In the heat treatment step performed after the second lathe processing step, the first connection portion 11 is softened by heat treatment. This makes it possible to crimp the conductor 7 to the first connection part 11 with a relatively weak force in the crimping process in the subsequent process, reducing the amount of stress relaxation when the terminal 1 side is energized, and The bond at the crimped portion can be further strengthened and maintained.

In the first forging step performed after the heat treatment step, the end of the second connecting portion 12 on the side to which the first connecting portion 11 is not joined is placed in a mold and compressed, thereby forming the second connecting portion 12. A plate-like connecting portion 12b is formed on the plate-like connecting portion 12b.

In a punching step performed after the first forging step, a through hole S is provided in the plate-like connecting portion 12b by punching.

In a plating process performed after the punching process, the terminal 1 is produced by plating the surfaces of the first connection part 11 and the second connection part 12. More specifically, after Cu base plating is applied to the surfaces of the first connection part 11 and the second connection part 12 to improve adhesion, the outermost layer is subjected to Sn plating.

Furthermore, in order to connect an aluminum electric wire to the obtained terminal 1, the following steps are performed.

First, in the compound insertion step, a compound material is inserted into the inner surface of the conducting wire connecting portion 11b in order to improve the adhesion between the conducting wire 7 and the conducting wire connecting portion 11b. The compound material is mainly composed of mineral oil and zinc powder, and is used to properly connect the conductive wire 7 and the conductive wire connection portion 11b. More specifically, the compound material plays roles such as ensuring good conductivity of the aluminum wire with the aluminum crimp terminal, destroying the oxide film of the conductor 7 and the oxide film of the conductor connection portion 11b, and waterproofing the crimp portion.

In the crimping process performed after the compound insertion process, the conductor 7 is inserted into the conductor connection part 11b, and a force is applied to the conductor connection part 11b from one direction using a crimping tool, thereby bonding the conductor 7 and the conductor connection part 11b. Crimp. The larger the depression amount of the crimping recess, which is the depressed portion of the conducting wire connecting portion 11b, in other words, the larger the pushing force during crimping, the more firmly the conducting wire 7 and the conducting wire connecting portion 11b are joined.

<Second embodiment>
FIG. 2 is a longitudinal sectional view showing the internal structure of the terminal of the second embodiment. In addition, each component shown in FIG. 2 is given the same reference numeral when it is the same as the component of the terminal 1 shown in FIG.

In the terminal 1 shown in the first embodiment, the first connecting portion 11 and the second connecting portion 12 have the same diameter (wire diameter), but the present invention is not limited to this. For example, as shown in the terminal 1A of FIG. 2, the first connecting portion 11 and the second connecting portion 12 may have different diameters.

More specifically, the first connection part 11 and the second connection part ₁₂ are such that the joint surface 3A is The length dimension of the joining line 30A, which is the exposed line, is the equivalent circle diameter D ₁ of the first end 11 a of the first connecting portion 11 and the equivalent circle diameter D 2 of the second end 12 a of the second connecting portion _{12 .} It is preferable that the diameter is larger than the smaller equivalent circle diameter by a size of 0.6% or more and 21.1% or less. In particular, by increasing the length of the joining line 30A by 0.6% or more with respect to the smaller of the equivalent circle diameters _D1 and _D2 , it is possible to withstand larger bending loads. It can also be durable. On the other hand, if the length dimension of the joining line 30A is made larger than 21.1% of the smaller equivalent circle diameter of the circle equivalent diameters _D1 and _D2 , the first connection part 11 and the second connection part 11 and the second Since the force applied when friction welding the connecting portion 12 is dispersed, cracks are likely to occur on the joint surface 3A. In particular, it is more preferable that the length of the joining line 30A is greater than or equal to 2.0% and less than or equal to 11.0% with respect to the smaller of the equivalent circle diameters D ₁ and D ₂ .

The bonding line 30A is a bonding surface 3A formed at a portion where the first opposing surface 31A of the first connecting portion 11 and the second opposing surface 32A of the second connecting portion 12 face each other, as shown in FIG. It is visible in a longitudinal section like this. Therefore, in the terminal 1A of this embodiment, as shown in FIG. Contains parts not included in

In the terminal 1 shown in the first embodiment, the joint surface 3 of the first connecting portion 11 and the second connecting portion 12 is relative to the outer circumferential surface 21 of the first end portion 11a and the outer circumferential surface 22 of the second end portion 12a. Although an embodiment has been shown in which the plane is configured to be a perpendicular plane, the present invention is not limited thereto. For example, as shown in the terminal 1A in FIG. 2, the joint surface 3A of the first connecting portion 11 and the second connecting portion 12 is connected to the outer circumferential surface 21 of the first end 11a or the outer circumferential surface 22 of the second end 12a. It may also be configured non-vertically.

In particular, as shown in FIG. 2(a), when the terminal 1A is cut along the longitudinal direction X passing through the center position _C0 of the bonding surface 3A, the bonding surface 3A is exposed. The joining line 30A, which is a line in which the outer peripheral surface 21 of the first end 11a of the first connecting part 11 is exposed, the first outer peripheral line 21a, which is a line where the outer peripheral surface 21 of the first end 11a of the first connecting part 11 is exposed, and the outer periphery of the second end 12a of the second connecting part 12. The average joint angle that is the average of angles θ ₁ and θ ₂ at joint end positions T ₁ and T ₂ between the surface 22 and any one of the second peripheral lines 22 a that are exposed lines is , preferably in the range of 78° or more and 88° or less. Thereby, the bonding strength between the first connecting portion 11 and the second connecting portion 12 can be further increased. On the other hand, when the average joining angle exceeds 88°, the maximum tensile stress due to bending occurs at or near the outer circumferential surfaces 21 and 22 of the terminal 1A, so cracks generated at these parts are likely to propagate to the inside of the terminal 1A. Cracking progresses more easily. Therefore, the average joining angle is more preferably 78° or more and 84° or less.

Here, the joint end positions T ₁ and T ₂ are the inner peripheral line of the first outer peripheral line 21a and the second outer peripheral line 22a (the second outer peripheral line 22a in FIG. 2(a)), and the joint line 30A, and are located on both outer circumferential lines. Further, the angles θ ₁ and θ ₂ at the joint end positions T ₁ and T ₂ are angles formed by the outer circumferential line and the joint line 30A, respectively, but the angles are obtuse angles exceeding 90° (for example, 95°). In this case, it refers to an acute angle (for example, 85°) between the extension line of the outer circumferential line and the joining line 30A, regardless of the description in FIG. 2(a).

In the terminal 1 shown in the first embodiment, the bonding surface 3 of the first connecting portion 11 and the second connecting portion 12 is configured as a flat surface, but the present invention is not limited thereto. For example, as shown in the terminal 1A of FIG. 2, the joint surface 3A of the first connecting portion 11 and the second connecting portion 12 may be configured by a curved surface. Since the bonding surface 3A is composed of a curved surface having protrusions, undulations, etc., even if a crack occurs on or near the outer peripheral surfaces 21, 22 of the terminal 1A, the tensile stress at the tip of the crack is dispersed, so that the crack can be removed from the terminal. It is possible to make it difficult for the light to be transmitted to the inside of 1A.

In particular, as shown in FIG. 2(b), when the terminal 1A is cut along the longitudinal direction X passing through the center position _C0 of the bonding surface 3A, the bonding surface 3A is exposed. The joining line 30A, which is a line formed by the bonding line 30A, may extend in the longitudinal direction X over a joining range 54 corresponding to 2% or more of the equivalent circle diameter of the joining surface 3A. At this time, the terminal 1A has two or more points of intersection between the perpendicular line Q perpendicular to the longitudinal direction It is preferable to have a range. For example, the terminal 1A in FIG. 2(b) is configured to have intersection points M ₁ and M ₂ as intersections between the perpendicular line Q perpendicular to the longitudinal direction X in this range and the joining line 30A. Here, one end or both ends of the range having two or more points of intersection with the joining line 30A may overlap with one end or both ends of the joining range 54. Note that the equivalent circle diameter of the joint surface 3A is the smaller of the equivalent circle diameter _D1 of the first end 11a of the first connecting portion 11 and the equivalent circle diameter _D2 of the second end 12a of the second connecting portion 12. It can be set as the equivalent circle diameter.

In addition, from the viewpoint of suppressing the propagation of cracks from the center position C ₀ to the intersection points M ₁ and M ₂ , it is preferable that the straight line distances from the center position C ₀ to the intersection points M ₁ and M ₂ are equal. , each is preferably short. Further, the maximum value of the straight line distance from the center position C ₀ to the intersection M ₁ and the intersection M ₂ is the circle equivalent diameter D 1 of the first end 11a of the first connection portion 11 and the circle equivalent diameter D ₁ of the second connection portion 12, respectively. It is preferable that the equivalent circle diameter _D2 of the two end portions 12a is one-third or less of the smaller equivalent circle diameter. On the other hand, if there are intersections M ₁ and M ₂ near the outer peripheral surfaces 21 and 22 of the terminal 1A, a gap will likely exist at that position depending on the manufacturing conditions, promoting crack propagation. The straight line distance from ₀ to the intersection point M ₁ or the intersection point M ₂ is the equivalent circle diameter D ₁ of the first end 11 a of the first connection portion 11 and the equivalent circle diameter D 2 of the second end 12 a of the second connection portion ₁₂ It is preferable that the diameter is one-tenth or more of the smaller equivalent circle diameter.

The bonding surface 3A constituted by such a curved surface is an end surface of an Al-based material that becomes the first end 11a of the first connecting portion 11 and an end surface of the Cu-based material that becomes the second end 12a of the second connecting portion 12. It can be manufactured by performing lathe processing on one or both of the end faces and forming protrusions and grooves in the portions that will become the first end 11a and the second end 12a.

For example, as shown in FIG. 3(a), a portion of the Cu-based material that will become the second end 12a is lathed to form a circular base having a diameter _L1 and a height H as the protrusion 12c. In this case, as shown in FIG. 3(b), the terminal 1B has a convex portion 12c' at the second end 12a, and there is a bonding line 30B, which is a line where the bonding surface 3B is exposed. It is possible to obtain a joint region 54 having intersection points M ₃ and M ₄ with a perpendicular line Q perpendicular to the longitudinal direction X.

In addition, as shown in FIG. 4(a), when a portion of the Cu-based material that will become the second end 12a is lathed to form a cone with a height H as the protrusion 12d, the height H may be adjusted appropriately. By adjusting, as shown in FIG. 4(b), the terminal 1C has a convex portion 12d' on the second end 12a, and the bonding line 30C, which is the line where the bonding surface 3C is exposed, and the first A first outer circumferential line 21a, which is a line where the outer circumferential surface 21 of the end portion 11a is exposed, and a second outer circumferential line 22a, which is a line where the outer circumferential surface 22 of the second end portion 12a of the second connecting portion 12 is exposed. To obtain an object in which the average of the angles θ ₃ and θ ₄ at the joint end positions T ₅ and T ₆ is in the same range as the above-mentioned angles θ ₁ and θ ₂ , for example, in the range of 78° or more and 88° or less. I can do it. Further, this terminal 1C can have intersection points M ₅ and M ₆ between the joining range 54, which is the range where the joining line 30C exists, and the perpendicular line Q perpendicular to the longitudinal direction X.

In addition, as shown in FIG. 5(a), a portion of the Cu-based material that will become the second end 12a is lathe-processed to form a groove 12e with a groove depth E, a groove width _L2 , and a diameter L of the groove inner wall surface. ₃ , as shown in FIG. 5(b), the terminal 1D has a recess 12e' in the first end 11a, and a bonding line 30D, which is a line where the bonding surface 3D is exposed. It is possible to obtain an intersection point M ₇ , M ₈ , M ₉ , M ₁₀ between the joining range 54, which is the range where the joining line 30D exists, and the perpendicular line Q perpendicular to the longitudinal direction X. can.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes all aspects included in the concept of the present invention and the scope of the claims. It can be modified to .

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.

(Invention Examples 1 to 20 and Comparative Examples 1 to 6)
An aluminum round bar made of alloy number 1070-O with a wire diameter of 19 mm and a copper round bar made of alloy number 1100-O with a wire diameter of 19 mm were prepared, and a terminal was produced in the following steps. However, for Inventive Example 11, a round bar of aluminum alloy number 6101 was used as the aluminum round bar. Further, for Inventive Example 12, a brass C2600 round rod was used as the copper round rod. Further, for Inventive Example 13, round bars with a wire diameter of 8 mm were used as the aluminum round rod and the copper round rod, respectively. Further, for Inventive Example 14, round bars with a wire diameter of 25 mm were used as the aluminum round rod and the copper round rod, respectively.

First, in Examples 15 to 20 of the present invention, as the first lathe processing step, the end face of the copper round bar is lathed to form a cone with a height H listed in Table 1 and a cone with a diameter L ₁ listed in Table 1. A circular base having a base portion with a height H, a circular groove having a groove depth E, a groove width L, and a diameter L ₃ of the inner wall surface of the groove described in Table 1 is used as a projection or groove at the second end 12a. It was formed in the part where it becomes. In other examples of the present invention and comparative examples, the first lathe processing step was not performed.

Next, as a friction welding process, the aluminum round bar that will become the first connection part 11 and the copper round bar that will become the second connection part 12 are placed in a jig of a friction welding device in a state facing each other, and the aluminum The round rod and the copper round rod are rotated relative to each other at the rotational speeds listed in Table 1, and the "Presence or absence of water injection to the part where the aluminum round rod and copper round rod contact" column in Table 1 is set to "Yes". '', the aluminum round rod and the copper round rod were heated by friction by pressing them at the rotational pressing pressure and pressing time listed in Table 1 while spraying water on the contact area. . Thereafter, the rotation was stopped at the time shown in Table 1, and then the aluminum round bar and the copper round bar were joined by pressing with the upset pressure shown in Table 1.

After the friction welding process, as a second lathe process, the end of the first connection part 11 on the side where the second connection part 12 is not joined is cut by lathe process so that it becomes hollow, and the conductor is connected. A portion 11b was formed. Next, as a heat treatment step, heat treatment was performed at a heating temperature of 350° C. and a holding time of 2 hours to soften the first connecting portion 11.

After that, as a first forging process, the end of the second connecting part 12 on the side to which the first connecting part 11 is not joined is placed in a mold and compressed, thereby forming a plate-shaped connection to the second connecting part 12. A portion 12b was formed. In the formed plate-like connection part 12b, a through-hole S was provided in the plate-like connection part 12b by punching as a punching process.

Next, as a plating process, the surfaces of the first connection part 11 and the second connection part 12 were subjected to Cu base plating to improve adhesion, and then Sn plating was applied to the outermost layer, thereby producing the terminal 1. .

[Various measurement and evaluation methods]
The characteristics described below were evaluated using the terminals according to the above-mentioned examples of the present invention and comparative examples. The evaluation conditions for each characteristic are as follows.

[1] Measurement regarding material structure [1-1] Measurement of the end position of the microcrystalline region of the first connection part A longitudinal cross section was cut out along the longitudinal direction of the obtained terminal so as to pass through the center position of the joint surface, and the joint was performed. The periphery of the longitudinal section including the plane was filled with resin, the sample surface was finished to a mirror finish by wet polishing and buffing, and then electropolishing and anodizing were performed to obtain an analysis sample. The area around the joint interface of this analysis sample is photographed using an optical microscope with a polarizing plate inserted, and the resulting image is divided into areas within a range of more than 0% and 1% or less of the equivalent circle diameter from the joint surface, and 1% When the average crystal grain size of the Al-based material is measured in sections of 1% of the equivalent circle diameter from the bonding surface in the same manner as in the sections in the range of 2% or less, the average crystal grain size is 3 μm or less. Among the sections corresponding to the microcrystalline region, the terminal position in the section farthest from the bonding surface, with the bonding surface as the starting point, was determined. Here, the terminal position of the microcrystalline region is expressed as a relative value when the size of the equivalent circle diameter of the bonding surface is taken as 100%. The results are shown in Table 2.

[1-2] Measurement of the ratio of the average crystal grain size of the Al-based material in the first peripheral region to the average crystal grain size of the Al-based material in the first central region in the microcrystalline region Obtained in [1-1] above In the image that is displayed, a line that spans 50 grain boundaries along the center line is included in the microcrystalline region, which is a section where the average grain size is 3 μm or less, as a line segment included in the first central region. The average crystal grain size of the Al-based material at the center line position was determined by drawing the line segment along the longitudinal direction and dividing the length of the portion of the line segment that spanned the grain boundary by 50. Similarly, regarding the average crystal grain size of the Al-based material in the first outer circumferential area, regarding a longitudinal section including the first outer circumferential area when the terminal is cut along the longitudinal direction so as to pass through the center position of the joint surface, Using an optical microscope with a magnification of 1000 times, a photograph was taken in an observation area of 105 μm in width x 80 μm in height, and a distance corresponding to 5% of the equivalent circle diameter was placed inward from the outer periphery of the bonding surface in the first outer peripheral region of the part corresponding to the microcrystalline region. It was calculated by drawing a line segment in the longitudinal direction that passes through a certain fourth position and spanning 50 grain boundaries, and dividing the length of the part of the line segment that spans grain boundaries by 50. . Then, the ratio was determined from the values of the average crystal grain size of the Al-based material in the first central region and the average crystal grain size of the Al-based material in the first peripheral region. The results are shown in Table 2.

[1-3] Measurement of the ratio of the average crystal grain size of the Cu-based material in the third region to the average crystal grain size of the Cu-based material in the second region at the second connection part Obtained in [1-1] above The area around the joint surface of the analysis sample is photographed using an optical microscope with a polarizing plate inserted, and the resulting image is a line obtained by translating the joint line, which is the line where the joint surface is exposed, in the longitudinal direction. , from the center position of the joint surface to a section within a range of more than 0% to 1% of the equivalent circle diameter from the joint surface, and a section within a range of more than 1% to 2% of the equivalent circle diameter, for each 1% of the equivalent circle diameter. The average crystal grain size of the Cu-based material in the second region, which is a section in the range of more than 0% and 3% or less, when measuring the average crystal grain size of the Cu-based material by dividing up to 20%, and 15 The average crystal grain size of the Cu-based material in the third region, which is a section in the range of more than 20%, was determined. Then, the ratio was determined from the obtained average crystal grain size of the Cu-based material in the second region and the average crystal grain size of the Cu-based material in the third region. The results are shown in Table 2.

[2] Measurement and evaluation of the shape of the joint surface Of the analysis sample obtained in [1-1] above, the area around the joint surface was photographed using an optical microscope, and the obtained image was taken with reference to the scale. The length dimension of the bonding line, which is the line where the bonding surface was exposed, was calculated. In addition, the equivalent circle diameter of the first end of the first connection part and the equivalent circle diameter of the second end of the second connection part are determined, and for the smaller of these, the equivalent circle diameter of the joining line is determined. The ratio of increase in length dimension was determined.

Also, from this image, we can see that the bonding line is the line where the bonding surface is exposed, and the outer circumferential line is the line where the outer circumferential surface of the first or second end on both sides of the bonding line is exposed. The average of the angles at the joint end positions, which are the angles with the first end and the second outer circumferential line, was determined to be the average joint angle of the first end and the second end. Here, when the angle between the outer circumferential line and the joining line is an obtuse angle, the acute angle between the extension line of the outer peripheral line and the joining line is defined as the angle at the joining end position.

Further, from this image, the size along the longitudinal direction of the bonding area, which is the area where the bonding line exists, was measured, and the relative value was determined when the equivalent circle diameter of the bonding surface was taken as 100%. In addition, the presence or absence of a range in which two or more points of intersection of the perpendicular line perpendicular to the longitudinal direction and the joining line were formed in this joining range was investigated. The results are shown in Table 2.

[3] Measurement of the scanning length of the region where the detection intensity of Al and Cu is 90% or less For the longitudinal section of the obtained terminal cut along the longitudinal direction passing through the center position of the bonding surface, On a line parallel to the longitudinal direction (center line) passing through the center position of WDX analysis was performed. From the obtained data, the detected intensities of Al and Cu at the center line near the joint surface are both detected at an intensity ratio of 90% or less relative to the total detected intensities of all elements analyzed. The scanning length of the area was measured. The results are shown in Table 2.

[4] Evaluation of 3-point bending test The bending strength was measured by a 3-point bending method in accordance with JIS Z2248 in the arrangement shown in FIG. More specifically, two jigs R ₂ and R ₃ are provided on the lower side of the sample material, and the joint surfaces are provided at equal intervals between the two jigs R ₂ and R ₃ . When the sample material is fixed and a load F is applied to the joint with the jig _R1 attached to the head of the tensile tester from above, the sample material is deformed into a shape along the jig _R1 . The presence or absence of cracks in and around the joints was evaluated. Here, as the test material, an aluminum conducting wire was inserted and crimped into the conducting wire connection part, and a copper plate material, which is another conductive member, was fixed with bolts to the plate-like connection part. In this sample material, the conductive wire and other conductive members were configured so that the aluminum conductive wire and the copper plate extended the same distance from the joint surface. Further, the lower jigs R ₂ and R ₃ were both cylindrical (depth 20 mm) with tips having a radius of curvature of 50 mm, and were arranged at an interval of 100 mm. On the other hand, the upper jig _R1 had a cylindrical tip (depth 20 mm) with a radius of curvature listed in Table 1. Further, the pushing displacement amount of the upper jig _R1 was set to be equal to the thickness of the terminal. In addition, if the obtained terminal had a step at or near the joint, the step was removed using a grinder or a file and used as a test material.

When the test materials were visually observed after the test, those in which no cracks occurred were evaluated as "○" because they were able to withstand bending at a predetermined radius of curvature. On the other hand, in the visual observation of the sample materials after the test, those in which cracks were generated were evaluated as "x" because they could not withstand bending at a predetermined radius of curvature. The results are shown in Table 2.

From the results in Tables 1 and 2, it can be seen that in the terminals of Examples 1 to 20 of the present invention, the terminal position of the microcrystalline region is within the first region, and the average amount of Al-based material in the first central region of this microcrystalline region is Since the ratio of the average crystal grain size of the Al-based material in the first outer peripheral region to the crystal grain size was in the range of 0.75 or more and 1.25 or less, it was bent along a jig _R1 with a curvature radius of 100 mm. In the evaluation of the 3-point bending test at that time, it was evaluated as "○".

On the other hand, in the terminals of Comparative Examples 1, 2, 3, and 5, the terminal position of the microcrystalline region was located closer to the bonding surface than the first region, and was outside the appropriate range of the present invention. Therefore, the terminals of Comparative Examples 1, 2, 3, and 5 were evaluated as "x" in the three-point bending test when bent along the jig _R1 with a radius of curvature of 100 mm.

Furthermore, in the terminal of Comparative Example 4, the terminal position of the microcrystalline region was located closer to the conducting wire than the first region, which was outside the appropriate range of the present invention. Further, the present invention is also characterized in that in the microcrystalline region, the ratio of the average crystal grain size of the Al-based material in the first peripheral region to the average crystal grain size of the Al-based material in the first central region exceeds 1.25. was outside the appropriate range. Therefore, the terminal of Comparative Example 4 was evaluated as "x" in the three-point bending test when it was bent along the jig _R1 with a radius of curvature of 100 mm.

Further, in the terminal of Comparative Example 6, in the microcrystalline region, the ratio of the average crystal grain size of the Al-based material in the first outer peripheral region to the average crystal grain size of the Al-based material in the first central region exceeds 1.25. This was outside the appropriate range of the present invention. Therefore, the terminal of Comparative Example 6 was evaluated as "x" in the evaluation of the three-point bending test when it was bent along the jig _R1 having a radius of curvature of 100 mm.

From this result, it is found that the terminal of the example of the present invention has the terminal position of the microcrystalline region within the first region, and the first outer periphery in this microcrystalline region with respect to the average crystal grain size of the Al-based material in the first central region. It was confirmed that cracking due to bending or tension is less likely to occur when the ratio of the average crystal grain size of the Al-based material in the range is in the range of 0.75 or more and 1.25 or less.

1, 1A to 1D Terminal 11 First connection part 11a First end part 11b Conductor connection part 12 Second connection part 12a Second end part 12b Plate connection part 12c, 12d Projection 12c', 12d' Convex part 12e Groove 12e' Recessed portion 21 Outer circumferential surface of the first end 21a First outer circumferential line 22 Outer circumferential surface of the second end 22a Second outer circumferential line 3, 3A Joint surface 30A Joint line 31, 31A First opposing surface 32, 32A Second opposing surface 41 1st position 42 2nd position 43 3rd position 44 4th position 45 5th position 46 6th position 47 7th position 48 One end of joining range 49 Other end of joining range 51 First area 52 Second area 53 Third region 54 Joint range 61 First central region 62 First outer peripheral region 7 Conductor 8 Other conductor members 9 Fastening member C Center line C ₀ Center position of joint surface D Equivalent circle diameter of joint surface E Groove depth F Load H Height of protrusion L Diameter of ₁ protrusion L ₂ Groove width L Diameter of inner wall of ₃ groove M ₁ to M Intersection of ₁₀ perpendicular line and bonding line P An imaginary line passing through the center of the bonding surface and along the longitudinal direction of the terminal Plane Q Perpendicular to the longitudinal direction R ₁ to R ₃ Jig S Through hole T ₁ to T ₈ Joint end position X Longitudinal direction of terminal θ ₁ to θ ₄ Angle at joint end position

Claims (7)

a first connection part made of an Al-based material and connected to the conductor;
a second connection part made of a Cu-based material and to which another conductor member is connected;
has
A first end portion, which is a solid portion of the first connection portion, and a second end portion, which is a solid portion, of the second connection portion are joined while facing each other, and the first end portion is a solid portion of the first connection portion. A terminal in which a bonding surface is formed between a first opposing surface and a second opposing surface of the second end,
Viewed in a longitudinal section when cut along the longitudinal direction of the terminal passing through the center position of the joint surface,
The first connection part is
Starting from the bonding surface, the terminal position of the microcrystalline region in which the average crystal grain size of the Al-based material is 3 μm or less is a circle of the bonding surface in the longitudinal direction of the terminal, starting from the center position of the bonding surface. located within a first region defined by a first position separated by a dimension corresponding to 3% of the equivalent diameter of the joint surface and a second position separated by a dimension corresponding to 15% of the circular equivalent diameter of the joint surface, and ,
When the microcrystalline region is divided into a first central region and a first peripheral region located around the first central region, the average crystal grain size of the Al-based material in the first central region is A terminal in which the ratio of the average crystal grain size of the Al-based material in the first outer peripheral region is in a range of 0.75 or more and 1.25 or less. The terminal according to claim 1, wherein the first end of the first connecting portion and the second end of the second connecting portion both have a substantially cylindrical shape. Seen in the longitudinal section,
The second connection part is
Average crystal grains of the Cu-based material in a second region defined by the center position of the bonding surface and a fifth position spaced apart by a dimension corresponding to 3% of the circular equivalent diameter of the bonding surface in the longitudinal direction of the terminal. a sixth position separated by a dimension corresponding to 15% of the equivalent circle diameter of the joint surface in the longitudinal direction of the terminal from the center position of the joint surface with respect to the diameter; According to claim 1 or 2, the ratio of the average crystal grain size of the Cu-based material in the third region defined by the seventh position separated by a dimension corresponding to % is in the range of 0.75 to 1.25. Terminals listed. When viewed in the longitudinal section, the length of the joining line, which is the line where the joining surface is exposed, is equal to the circle equivalent diameter of the first end of the first connecting portion and the second connecting portion of the second connecting portion. The terminal according to any one of claims 1 to 3, wherein the terminal is larger than the smaller equivalent circle diameter by 0.6% or more and 21.1% or less among the equivalent circle diameters of the end portions. When viewed in the longitudinal section, a joining line is a line where the joining surface is exposed, a first outer peripheral line is a line where the outer peripheral surface of the first end of the first connecting part is exposed, and the second The average angle at the joint end position between the outer circumferential surface of the second end of the connecting part and any one of the second outer circumferential lines, which is the exposed line, is 78° or more and 88° or less. 5. A terminal according to any one of claims 1 to 4, wherein the terminal is within the range. When viewed in the longitudinal section, the bonding line, which is a line where the bonding surface is exposed, extends in the longitudinal direction over a bonding range of a size equivalent to 2% or more of the equivalent circle diameter of the bonding surface, and
According to any one of claims 1 to 5, at least a part of the joining range has a range where two or more intersections between a perpendicular line perpendicular to the longitudinal direction and the joining line are formed. terminal. When WDX analysis was performed on the vertical section by scanning along the longitudinal direction of the terminal, the detected intensities of Al and Cu were both expressed as an intensity ratio of 90 to the sum of the detected intensities of all the elements analyzed. 7. The terminal according to any one of claims 1 to 6, wherein the scanning length of the area where the distance is 5 μm or less is 5 μm or less.

Images