JP7016022B2 - Terminal - Google Patents

Description

The present disclosure relates to terminals.

Conventionally, Patent Document 1 discloses a terminal (columnar metal terminal) connected to the coil terminal by winding the coil terminal (metal wire).

Japanese Unexamined Patent Publication No. 11-186023

By the way, when the metal wire is wound around the columnar metal terminal, if the adhesion between the metal wire and the columnar metal terminal is low, the bonding strength between the metal wire and the columnar metal terminal may decrease.

Therefore, in the present disclosure, by improving the workability when winding the metal wire around the columnar metal terminal, the adhesion between the metal wire and the columnar metal terminal at the time of winding is improved, and the bonding strength between the two can be ensured. The purpose is to provide a terminal that can be used.

In order to achieve the above object, the terminal according to one embodiment of the present disclosure includes a columnar metal terminal and a metal wire wound around the columnar metal terminal, and the melting point of the first metal forming the metal wire is set. It is lower than the melting point of the second metal forming the columnar metal terminal, and an intermetal compound layer between the first metal and the second metal is provided at the interface between the metal wire and the columnar metal terminal.

According to the present disclosure, workability when winding a metal wire around a columnar metal terminal can be enhanced, and as a result, the bonding strength between the metal wire and the columnar metal terminal can be ensured.

FIG. 1 is a schematic view showing terminals according to an embodiment. FIG. 2 is a cross-sectional view showing a terminal according to an embodiment. FIG. 3 is an explanatory diagram showing a state in which a metal wire is entwined with a columnar metal terminal according to an embodiment. FIG. 4 is a flow chart showing a process of entwining a metal wire around a columnar metal terminal according to an embodiment. FIG. 5 is a diagram showing a process of making an assembly, thermocompression bonding, and joining according to an embodiment. FIG. 6 is a flow chart showing a process of joining a metal wire to a columnar metal terminal of an assembly according to an embodiment. FIG. 7 is an explanatory diagram illustrating a conduction path during resistance welding according to the embodiment. FIG. 8 is an enlarged image showing the intermetallic compound layer of the terminal and its periphery according to the embodiment. FIG. 9 is a graph showing the relationship between the ratio of the crack length to the interface length and the thickness of the intermetallic compound in the terminal according to the embodiment. FIG. 10 is a cross-sectional view showing the terminal according to the modified example 1. FIG. 11 is a cross-sectional view showing the terminal according to the modified example 2. FIG. 12 is a cross-sectional view showing the terminal according to the modified example 3. FIG. 13 is a front view showing a schematic configuration of the terminal according to the modified example 4. FIG. 14 is a cross-sectional view showing a terminal according to the modified example 4 in which a plurality of metal wires having different wire diameters are metal-bonded.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Each of the embodiments described below is a comprehensive or specific example. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, steps, the order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, the components not described in the independent claim indicating the highest level concept are described as arbitrary components.

It should be noted that each figure is a schematic view and is not necessarily exactly illustrated. Further, in each figure, the same reference numerals are given to substantially the same configurations, and duplicate explanations will be omitted or simplified.

Hereinafter, the terminal and the method of joining the terminal according to the embodiment of the present disclosure will be described.

[Constitution]
FIG. 1 is a schematic view showing a terminal 1 according to an embodiment. As shown in FIG. 1, the terminal 1 is provided with respect to the stator 100 which is a part of the motor. Specifically, the terminal 1 is provided on a plurality of coils 101 constituting the stator 100. The terminal 1 supplies electric power to the coil 101 from a circuit board mounted on a power supply unit that supplies electric power to the motor. The terminal 1 includes a columnar metal terminal 10 and a metal wire 20.

FIG. 2 is a cross-sectional view showing the terminal 1 according to the embodiment. Specifically, FIG. 2 is a cross-sectional view of the cut surface including the line II-II in FIG.

As shown in FIG. 2, the columnar metal terminal 10 is a columnar metal member electrically connected to the coil 101. The columnar metal terminal 10 is electrically connected to the metal wire 21 which is a part of the metal wire 20. Specifically, the columnar metal terminal 10 is joined to the metal wire 21 in a state in which the metal wire 21 is wound. The columnar metal terminal 10 is, for example, a member in which the periphery of a base metal layer 11 containing iron (Fe) as a main component is coated with a plating layer 12 made of a second metal containing copper (Cu) as a main component. In the present embodiment, the metal wire 21 and the columnar metal terminal 10 are joined in a state where the metal wire 21 is entwined with the columnar metal terminal 10. Here, "entangled" means that the wire is tied around the object in a wound state, and the portion where the metal wires 21 overlap each other due to the tied (intersection 23: FIG. 3). See) means that it exists. The metal wire 21 is singly wound around the columnar metal terminal 10 except for the intersection 23.

Metal bonding is, for example, a bonding method capable of forming an intermetallic compound layer composed of bonding objects at an interface between bonding objects. Metal bonding includes thermocompression bonding, ultrasonic bonding, diffusion bonding and resistance welding. In this embodiment, a case where the metal wire 21 is welded to the columnar metal terminal 10 by resistance welding, which is an example of metal bonding, will be described. Resistance welding is more suitable than other joining methods in terms of metal joining the metal wire 21 to the columnar metal terminal 10.

The base metal layer 11 is, for example, a rectangle having a short side of about 0.4 mm and a long side of 0.6 mm in the axial direction, and the thickness of the plating layer 12 is about 25 μm. Further, in the metal wire 20, the wire diameter of the metal wire 21 is about 0.15 mm.

The columnar metal terminal 10 is a quadrangle in the axial direction. The columnar metal terminal 10 is not limited to a quadrangle in the axial direction, and may be, for example, a polygonal shape other than the quadrangle, a circular shape, an elliptical shape, an oval shape, or the like.

The columnar metal terminal 10 has a rectangular cross section in a direction orthogonal to the axial direction of the columnar metal terminal 10, and has a pair of long side surfaces and a pair of short side surfaces. The long side surface is a surface whose cross section constitutes the long side of a rectangle, and the short side surface is a surface whose cross section constitutes the short side of a rectangle. The long side surface of the columnar metal terminal 10 is a joint terminal surface 110 to which the metal wire 21 is metal-bonded. The cross section of the columnar metal terminal 10 in the direction orthogonal to the axial direction may have a shape in which there is no distinction between a long side and a short side, that is, a square. In this case, the pair of facing side surfaces of the columnar metal terminal can be the joint terminal surface.

The metal wire 21 constitutes a part of the metal wire 20 and is a metal wire. Specifically, the metal wire 21 is formed of a first metal containing aluminum (Al) as a main component. The metal wire 21 forms an intersection 23 in which the metal wires 21 overlap each other in the circumferential direction of the columnar metal terminal 10. The intersection 23 is formed so as to be in contact with either short side surface.

An intermetallic compound layer 24 formed by metal bonding is formed at the interface between the bonding terminal surface 110 of the columnar metal terminal 10 and the metal wire 21. The intermetallic compound layer 24 is made of an alloy of the second metal forming the plating layer 12 and the first metal forming the metal wire 21. Specifically, the intermetallic compound layer 24 is formed by temporarily mixing the first metal and the second metal by resistance welding and then re-curing. The thickness (layer thickness) of the intermetallic compound layer 24 is preferably 5 μm or less.

[Terminal joining method]
A method of joining the metal wire 20 to the columnar metal terminal 10 will be described.

First, the columnar metal terminal 10 and the metal wire 20 before joining will be described.

The columnar metal terminal 10 is a rectangular columnar shape having a rectangular shape in the axial direction, and a pair of long side surfaces thereof are joint terminal surfaces 110. Further, the intersecting portion 23 of the metal wire 21 is not arranged on the joint terminal surface 110, and the intersecting portion 23 is arranged only on the pair of short side surfaces of the columnar metal terminal 10. The columnar metal terminal 10 is, for example, a member in which the periphery of the base metal layer 11 is covered with the plating layer 12, and the intermetallic compound layer 24 is not formed at the time before joining. As described above, since the plating layer 12 is formed of a second metal containing copper as a main component, it has a melting point according to the melting point of copper (1083 ° C.).

Further, in the metal wire 20, the metal wire 21 is coated with a resin layer 22 made of an insulating resin. The metal wire 20 is, for example, an enamel wire, a lead wire, or the like. The metal wire 21 is made of, for example, a first metal containing aluminum as a main component. The resin layer 22 is made of a resin material such as urethane, polyester, polyesterimide, or polyamideimide. Further, as described above, since the metal wire 21 is formed of a first metal containing aluminum as a main component, it has a melting point according to the melting point of aluminum (660 ° C.).

FIG. 3 is an explanatory diagram showing a state in which the metal wire 20 is entwined with the columnar metal terminal 10 according to the embodiment. FIG. 3A shows a state in which the metal wire 20 is entwined with the columnar metal terminal 10 as viewed from a direction orthogonal to the axial direction of the columnar metal terminal 10. FIG. 3B shows a state in which the metal wire 20 is entwined with the columnar metal terminal 10 as viewed from the axial direction of the columnar metal terminal 10. Further, FIG. 4 is a flow chart showing a process of entwining the metal wire 20 with the columnar metal terminal 10 according to the embodiment.

As shown in FIGS. 3 and 4, first, the columnar metal terminal 10 is fixed to a jig (not shown). As a result, the columnar metal terminal 10 is in a state where the metal wire 20 can be wound (S111). After that, the metal wire 20 is wound around the columnar metal terminal 10 while receiving a constant tension. As described above, the metal wire 21 of the metal wire 20 is formed of a first metal containing aluminum as a main component. The melting point of the first metal is lower than the melting point of the second metal forming the plating layer 12. Specifically, the melting point of the first metal is 300 ° C. or higher lower than the melting point of the second metal. That is, when the temperature is the same, the metal wire 21 is more flexible than the plating layer 12. Since the resin layer 22 covering the metal wire 21 is also more flexible than the metal, the metal wire 20 is generally more flexible than the plating layer 12. At the time of winding, the relatively flexible metal wire 20 is wound around the plating layer 12 having a relatively high hardness, so that the metal wire 20 can be easily brought into close contact with the plating layer 12.

Further, when the metal wire 20 is wound around the first turn and the second turn, the metal wire 20 is wound around the columnar metal terminal 10 so as to overlap the winding start portion of the metal wire 20. As a result, an intersection 23 in which the metal wires 20 intersect with each other is formed (S112). The intersection 23 is arranged so as to avoid the joint terminal surface 110 of the columnar metal terminal 10 and come into contact with any of the short side surfaces.

Further, the metal wire 20 is wound around the columnar metal terminal 10 for several turns (S113). The metal wire 20 is wound around the columnar metal terminal 10 so as to be substantially coiled except for the intersection 23. After that, unnecessary parts of the metal wire 20 are cut with nippers or the like, and the metal wire 20 is arranged to obtain the assembly 200 shown in FIG. FIG. 5 is a diagram showing steps of making, thermocompression bonding, and joining the assembly 200 according to the embodiment.

Next, the metal wire 20 is joined to the columnar metal terminal 10. In the present embodiment, the metal wire 20 is realized by thermocompression bonding and resistance welding to the columnar metal terminal 10.

FIG. 6 is a flow chart showing a step of joining the metal wire 20 to the columnar metal terminal 10 of the assembly 200 according to the embodiment. As shown in FIGS. 5 and 6, first, the above-mentioned assembly 200 is arranged between a pair of welding electrodes 30 provided in a resistance welder (S121). Specifically, the assembly 200 is arranged between the pair of welding electrodes 30 so that the pair of bonding terminal surfaces 110a of the columnar metal terminals 10 and the pair of welding electrodes 30 face each other on a one-to-one basis.

Next, the assembly is thermocompression bonded by a pair of welding electrodes 30 (S122). At this time, the resistance welder passes a current as shown by an arrow Y1 in FIG. 5 through the pair of welding electrodes 30. At the same time, the resistance welder sandwiches the metal wire 21 with a pair of welding electrodes 30 and applies a load so that the metal wire 21 is crushed. As a result, the pair of welding electrodes 30 generate heat to heat the metal wire 20, so that the resin layer 22 of the metal wire 20 is melted and peeled off from the metal wire 21 of the metal wire 20 to be removed. The pair of welding electrodes 30 pushes the metal wire 21 by a predetermined pushing amount. Further, since the metal wire 21 and the columnar metal terminal 10 are crimped by the pair of welding electrodes 30, the metal wire 21 and the columnar metal terminal 10 come into contact with each other.

Next, the resistance welding machine causes the metal wire 21 and the metal wire 21 to flow due to the electric resistance between the columnar metal terminal 10 and the metal wire 21 by passing an electric current through the pair of welding electrodes 30 as shown by the arrow Y2 in FIG. Joule heat is generated in the columnar metal terminal 10. As a result, the metal wire 21 is melted, and the metal wire 21 is resistance welded to the columnar metal terminal 10 (S123).

Then, the resistance welder releases the load applied to the assembly by the pair of welding electrodes 30. In this way, the terminal 1 in which the metal wire 21 is electrically connected to the columnar metal terminal 10 can be obtained.

Next, the pushing amount at the time of thermocompression bonding performed in step S122 of FIG. 6 will be specifically described. The resistance welder pushes the metal wire 21 in the direction in which the pair of welding electrodes 30 approach each other. Specifically, the resistance welder applies a load to the metal wire 20 by a pair of welding electrodes 30 and pushes the metal wire 20 with a specified load calculated by using the diameter, the number of turns, and the withstand force of the metal wire 20 or more. , Transform. The position obtained by subtracting the pushing amount of the metal wire 20 from the diameter of the metal wire 20 is the height of the metal wire 20 from the columnar metal terminal 10.

Further, in order to appropriately thermocompression-bond the metal wire 20 by the pair of welding electrodes 30, a load cell is used to detect that the metal wire 21 and the pair of welding electrodes 30 are in contact with each other. As a result, the resistance welder can push the metal wire 21 with the pushing amount from the point of contact with the metal wire 21.

When the metal wire 21 is pushed into the welding electrode 30 on one side by a predetermined pushing amount, the metal wire 21 is deformed according to the pushing amount. In this way, the surface of the metal wire 21 on the outer peripheral side of the terminal 1 is flattened, the metal wire 21 wound for several turns and the plurality of contact surfaces of the welding electrode 30 are evenly contacted, and electricity is supplied through all the contact surfaces. It will be possible.

By winding the metal wire 21 around the columnar metal terminal 10 for a plurality of turns, it is possible to secure the parallelism between the welding electrode 30 and the assembly 200. Further, it becomes possible to disperse the load applied to each metal wire 21. By dispersing the load applied to the metal wire 21, the amount of deformation of the metal wire 21 becomes insensitive to the load. If it is insensitive to a load, it is unlikely to be deformed even with a large load, so that it becomes easy to control the load during thermocompression bonding and resistance welding. That is, it becomes easy to control the amount of deformation of the metal wire during thermocompression bonding and resistance welding by a load.

Next, the joining in step S123 of FIG. 6 will be specifically described.

First, when the metal wire 20 is resistance-welded to the columnar metal terminal 10, if the temperature of the metal wire 21 rises too high, the metal wire 21 may be crushed, resulting in disconnection or melting. Therefore, the resistance welder controls the current flowing through the pair of welding electrodes 30 so that defects such as disconnection or fusing do not occur in the metal wire 21.

FIG. 7 shows an assembly 200 arranged between the pair of welding electrodes 30. FIG. 7 is an explanatory diagram illustrating a conduction path during resistance welding according to the embodiment. FIG. 7 is a view of the assembly 200 as viewed in the axial direction.

As shown in FIG. 7, the path through which the current flows linearly from one welding electrode 30 to the other welding electrode 30 via the assembly 200 is defined as the conduction path D1, and from one welding electrode 30 to the other welding electrode 30. The paths of the current flowing through the metal wire 21 bypassing the columnar metal terminal 10 are the conduction paths D2 and D3.

Here, when a current is passed from one welding electrode 30 to the other welding electrode 30, the electric resistance value between the metal wire 21 of the metal wire 20 on one side and the columnar metal terminal 10 and the metal wire 20 on the other side are obtained. Due to the electric resistance value between the metal wire 21 and the columnar metal terminal 10, Joule heat is generated in the metal wire 21 and the columnar metal terminal 10. In addition, Joule heat is generated due to the electric resistance value of each element constituting the metal wire 21 and the columnar metal terminal 10. Gradually, the Joule heat generated in the base metal layer 11 of the columnar metal terminal 10 propagates to the plating layer 12 and the metal wire 21 of the columnar metal terminal 10. As a result, the plating layer 12 and the metal wire 21 of the columnar metal terminal 10 are locally melted on the contact surface between the metal wire 21 and the columnar metal terminal 10. As a result, aluminum, which is the main component of the metal wire 21, and copper, which is the main component of the plating layer 12, are mixed. After that, when the supply of electric current is stopped, an intermetallic compound layer 24 of aluminum and copper is formed at the interface between the metal wire 21 and the columnar metal terminal 10 (see FIG. 2).

By winding the metal wire 21 around the columnar metal terminal 10 for a plurality of turns, it is possible to disperse the current flowing through the individual metal wires 21. By dispersing the current flowing through the metal wire 21, the calorific value of the metal wire 21 becomes insensitive to the current value. If it is insensitive to the current during resistance welding, it is difficult to melt even with a large current, so it is possible to easily control the current value during resistance welding. That is, it becomes easy to control the molten state of the first metal and the second metal at the time of resistance welding by the current value.

[Effects, etc.]
As described above, the terminal 1 according to the present embodiment includes the columnar metal terminal 10 and the metal wire 20 wound around the columnar metal terminal 10, and the melting point of the first metal forming the metal wire 20 is The interface between the metal wire 20 and the columnar metal terminal 10 is provided with an intermetal compound layer 24 between the first metal and the second metal, which is lower than the melting point of the second metal forming the columnar metal terminal 10. ..

According to this, the melting point of the first metal forming the metal wire 20 is lower than the melting point of the second metal forming the columnar metal terminal 10. Therefore, when the metal wire 20 is under the same environmental temperature, the metal wire 20 is a columnar metal. It is in a more flexible state than the terminal 10. At the time of winding, the relatively flexible metal wire 20 is wound around the columnar metal terminal 10 having a relatively high hardness, so that the workability when winding the metal wire 20 around the columnar metal terminal 10 can be improved. can.

Further, by winding the relatively flexible metal wire 20 around the columnar metal terminal 10 having a relatively high hardness, the metal wire 20 can be easily brought into close contact with the columnar metal terminal 10. If the adhesion between the metal wire 20 and the columnar metal terminal 10 is high, thermocompression bonding and resistance welding can be stably performed. As a result, the bonding strength between the metal wire 20 and the columnar metal terminal 10 is ensured. Can be done.

Further, the melting point of the first metal is 300 degrees or more lower than the melting point of the second metal.

According to this, since the melting point of the first metal is 300 degrees or more lower than the melting point of the second metal, the metal wire 20 is in a more flexible state than the columnar metal terminal 10 under the same environmental temperature. Can be. Therefore, the workability at the time of winding can be further improved.

The main component of the first metal is aluminum, and the main component of the second metal is copper.

According to this, aluminum and copper are generally metals having low electrical resistance. A metal with low electrical resistance is insensitive to the current during resistance welding and can be said to be a metal that is difficult to weld. A metal with high electrical resistance is sensitive to the current during resistance welding, so if a constant current is applied, it will melt instantly. On the other hand, if it is insensitive to the current during resistance welding, it is difficult to melt even with a large current, so that it is possible to easily control the current value during resistance welding. That is, it becomes easy to control the molten state of the first metal and the second metal at the time of resistance welding by the current value.

Further, since the main component of the first metal is aluminum and the main component of the second metal is copper, the columnar metal terminal 10 and the metal wire 20 can be formed of relatively inexpensive aluminum and copper. Therefore, the manufacturing cost can be suppressed.

The thickness of the intermetallic compound layer 24 is 5 μm or less.

FIG. 8 is an enlarged image showing the intermetallic compound layer 24 of the terminal 1 and its periphery according to the embodiment. Specifically, FIG. 8 shows a region surrounded by the broken line L1 in FIG. In FIG. 8, the base metal layer 11, the plating layer 12, the intermetallic compound layer 24, and the metal wire 21 of the columnar metal terminal 10 are arranged in this order from the bottom. As shown in FIG. 8, crack C may occur in the intermetallic compound layer 24. The crack C extends along the axial direction of the columnar metal terminal 10 in the intermetallic compound layer 24. Here, the length of the intermetallic compound layer 24 in the axial direction of the columnar metal terminal 10 is defined as the interface length, and the length of the crack C in the same direction is defined as the crack length. Further, the length of the intermetallic compound layer 24 in the direction orthogonal to the axial direction of the columnar metal terminal 10 is defined as the thickness (layer thickness).

FIG. 9 is a graph showing the relationship between the ratio of the crack length to the interface length and the thickness of the intermetallic compound layer 24 in the terminal 1 according to the embodiment. As shown in FIG. 9, when the thickness of the intermetallic compound layer 24 is larger than 5 μm, it can be seen that crack C is generated in which the ratio of the crack length to the interface length is 100%. On the other hand, when the thickness of the intermetallic compound layer 24 is 5 μm or less, it can be seen that crack C in which the ratio of the crack length to the interface length is 100% does not occur. That is, if the thickness of the intermetallic compound layer 24 is 5 μm or less, it is possible to prevent the crack C from growing to the same level as the interface length.

Further, the columnar metal terminal 10 is a polygonal columnar shape, the metal wire 20 has at least one intersection 23 connected to the columnar metal terminal, and the intersection 23 is an intermetallic compound layer 24 in the columnar metal terminal 10. Is placed on the side where is not formed.

When the intersection 23 of the metal wire 20 is provided with respect to the joint terminal surface 110 of the columnar metal terminal 10, the intersection 23 is sandwiched between the pair of welding electrodes 30 during thermocompression bonding and resistance welding. Since the intersection 23 is thicker than the other parts of the metal wire 20, there are some parts that do not come into contact with the pair of weld electrodes 30 in the other parts. As a result, thermocompression bonding and resistance welding may not be reliably performed at the portion of the metal wire 20 other than the intersection 23.

On the other hand, when the crossing portion 23 of the metal wire 20 is provided on the side surface of the columnar metal terminal 10 other than the joint terminal surface 110, that is, the side surface on which the intermetallic compound layer 24 is not formed, the crossing portions 23 are paired. It is arranged in a place not sandwiched by the welding electrode 30. Therefore, since only the single-wound portions of the metal wire 20 are arranged on the joint terminal surface 110 of the columnar metal terminal 10, the pair of welding electrodes 30 can be reliably brought into contact with these portions. .. Therefore, the certainty of thermocompression bonding and resistance welding can be improved.

Further, in the above embodiment, since the base metal layer 11 of the columnar metal terminal 10 is formed of a metal containing iron as a main component having a relatively high electric resistance, Joule heat is efficiently generated during resistance welding. be able to. On the other hand, since the plating layer 12 is formed of a second metal whose main component is copper, which has a relatively low electrical resistance, current easily flows on the surface layer of the columnar metal terminal 10 during resistance welding, and the metal wire 20 It is possible to suppress the flow of electricity concentrated on the metal wire 21. Therefore, it is possible to suppress the fusing of the metal wire 21.

[Modification 1]
In the above embodiment, the terminal 1 in which the metal wire 20 is wound around the columnar metal terminal 10 having the plating layer 12 and metal-bonded is exemplified. In this modification 1, a terminal 1A in which a metal wire 20 is wound around a columnar metal terminal 10a having no plating layer and metal-bonded to the terminal 1A will be described. In the following description, the same parts as those in the above embodiment may be designated by the same reference numerals and the description thereof may be omitted.

FIG. 10 is a cross-sectional view showing the terminal 1A according to the modified example 1. Specifically, FIG. 10 is a diagram corresponding to FIG. 2. As shown in FIG. 10, the columnar metal terminal 10a provided in the terminal 1A is entirely formed of a second metal containing copper as a main component, and a plating layer is not formed on the surface thereof. That is, before the metal wire 20 is wound, the surface of the columnar metal terminal 10a is in a state where the second metal is exposed as a whole.

By winding the metal wire 20 around such a columnar metal terminal 10a and performing thermal pressure bonding and resistance welding, the metal wire 21 of the metal wire 20 is located on the joint terminal surface 110a of the columnar metal terminal 10a. A metal-to-metal compound layer 24a is formed and metal-bonded. The intermetallic compound layer 24a is composed of aluminum, which is the main component of the first metal forming the metal wire 21, and copper, which is the main component of the second metal forming the columnar metal terminal 10a.

[Modification 2]
In the above embodiment, the columnar metal terminal 10 in which the plating layer 12 is formed of the second metal containing copper as a main component is exemplified. In this modification 2, the columnar metal terminal 10b in which the plating layer 12b is formed by the second metal containing nickel (Ni) as a main component will be described.

FIG. 11 is a cross-sectional view showing the terminal 1B according to the modified example 2. Specifically, FIG. 11 is a diagram corresponding to FIG. 2. As shown in FIG. 11, in the columnar metal terminal 10b provided in the terminal 1B, a plating layer 12b formed of a second metal containing nickel as a main component is coated on the base metal layer 11.

By winding the metal wire 20 around such a columnar metal terminal 10b and performing thermal pressure bonding and resistance welding, the metal wire 21 of the metal wire 20 becomes a plating layer 12b on the joint terminal surface 110b of the columnar metal terminal 10b. And the metal-to-metal compound layer 24b are formed and metal-bonded. The intermetallic compound layer 24b is composed of aluminum, which is the main component of the first metal forming the metal wire 21, and nickel, which is the main component of the second metal forming the columnar metal terminal 10a. Since the plating layer 12b is formed of a second metal containing nickel as a main component, it has a melting point according to the melting point of nickel (1455 ° C.). That is, even in this case, the melting point of the first metal containing aluminum as a main component is 300 degrees or more lower than the melting point of the second metal.

[Modification 3]
In the above embodiment, the terminal 1 in which the metal wire 20 is wound around the columnar metal terminal 10 having the plating layer 12 and metal-bonded is exemplified. In the third modification, the terminal 1C in which the metal wire 20 is wound around the columnar metal terminal 10c having the double plating layers 12 and 12c and metal-bonded to the terminal 1C will be described.

FIG. 12 is a cross-sectional view showing the terminal 1C according to the modified example 3. Specifically, FIG. 12 is a diagram corresponding to FIG. 2. As shown in FIG. 12, in the columnar metal terminal 10c provided in the terminal 1C, the surface layer of the plating layer 12 is coated with a plating layer 12c made of a third metal containing tin (Sn) as a main component. The plating layer 12c is laminated on the entire surface of the plating layer 12 before the metal wire 20 is wound. Here, since the plating layer 12c is formed of a third metal containing tin as a main component, it has a melting point according to the melting point of tin (232 ° C.).

When the metal wire 20 is wound around such a columnar metal terminal 10c and heat-bonded, the columnar metal terminal 10c and the metal wire 20 are higher than the melting point of the third metal and lower than the melting point of the first metal. It is heated to the temperature. As a result, the plating layer 12c is pushed outward from the interface between the metal wire 20 and the plating layer 12 in order to receive the pressure from the pair of welding electrodes 30 in the molten state of the plating layer 12c.

After that, by performing resistance welding, the metal wire 21 of the metal wire 20 forms an intermetallic compound layer 24c with the plating layer 12 on the bonding terminal surface 110c of the columnar metal terminal 10c and is metal-bonded. The intermetallic compound layer 24c is composed of aluminum, which is the main component of the first metal forming the metal wire 21, and copper, which is the main component of the second metal forming the columnar metal terminal 10c. The plating layer 12c covers the surface of the plating layer 12 with the outer side of the metal wire 21 and the intermetallic compound layer 24.

As described above, if the columnar metal terminal 10c is provided with the plating layer 12c made of a third metal containing tin as a main component, the oxidation of the plating layer 12 made of a second metal containing copper as a main component can be suppressed. can. Further, the plating layer 12c fills the gap between the metal wire 21 and the columnar metal terminal 10c when it is melted during thermocompression bonding. By filling this gap, heat conduction during resistance welding is enhanced.

[Modification 4]
In the above embodiment, a case where one metal wire 20 is wound around a columnar metal terminal 10 and metal-bonded is exemplified. However, a plurality of metal wires may be wound around the columnar metal terminals. In this modification 4, as an example, a case where two metal wires 20d1 and 20d2 are wound around a columnar metal terminal 10d will be illustrated.

FIG. 13 is a front view showing a schematic configuration of the terminal 1D according to the modified example 4. As shown in FIG. 13, two metal wires 20d1 and 20d2 are wound around the columnar metal terminal 10d of the terminal 1D. Specifically, the two metal wires 20d1 and 20d2 have intersections 23d1 and 23d2, respectively, and these intersections 23d1 and 23d2 are arranged at positions where they do not overlap each other. Further, the two metal wires 20d1 and 20d2 are wound around the columnar metal terminal 10d in a double spiral shape so as not to overlap each other, and are metal-bonded to the columnar metal terminal 10d.

As described above, a plurality of metal wires 20d1 and 20d2 are provided, and each of them is wound around the columnar metal terminal 10d.

Thereby, by winding the plurality of metal wires 20d1 and 20d2 around one columnar metal terminal 10d, the columnar metal terminal 10d can be made common.

Here, the wire diameters of the plurality of metal wires 20d1 and 20d2 may be the same or different. Specifically, the wire diameters of the metal wires provided in each of the plurality of metal wires 20d1 and 20d2 may be the same or different.

FIG. 14 is a cross-sectional view of the terminal 1D according to the modified example 4 showing a state in which a plurality of metal wires 20d1 and 20d2 having different wire diameters are metal-bonded. In FIG. 14, only the metal wires 21d1 and 21d2 from which the resin layer has been removed are shown.

As shown in FIG. 14, in a plurality of metal wires 20d1 and 20d2 having different wire diameters, the metal wires 21d1 and 21d2 are metal-bonded to the plating layer 12 on the bonding terminal surface 110d of the columnar metal terminal 10. Therefore, the intermetallic compound layers 24d1 and 24d2 are formed at the boundary between the metal wires 21d1 and 21d2 and the columnar metal terminal 10. Here, the wire diameters of the metal wires 21d1 and 21d2 in the metal-bonded state are lengths z1 and z2 along the axial direction of the columnar metal terminals 10 in the metal wires 21d1 and 21d2. Here, the case where the wire diameter of the metal wire 21d1 is larger than that of the metal wire 21d2 is illustrated. Further, the thicknesses h1 and h2 of the metal wires 21d1 and 21d2 along the direction orthogonal to the axial direction of the columnar metal terminals 10 are the same.

Before the metal joining, the metal wires 21d1 and 21d2 had circular cross sections (virtual lines L11 and L12 in FIG. 14) having different wire diameters from each other. At the time of manufacturing the terminal 1D, the metal wires 21d1 and 21d2 having different wire diameters are first pressed against the columnar metal terminal 10 so that the thickness is made uniform in the thermocompression bonding step and the terminal 1D is in close contact with the plating layer 12. Further, by being pressed in the resistance welding step, the metal wires 21d1 and 21d2 are made uniform in thickness h1 and h2 and metal-bonded to the columnar metal terminal 10. By making the thicknesses of the metal wires 21d1 and 21d2 uniform in the thermocompression bonding process, the quality of the resistance welding process is stabilized. Since the melting points of the metal wires 21d1 and 21d2 are lower than those of the columnar metal terminals 10d, it is possible to easily make the thicknesses of the metal wires 21d1 and 21d2 having different wire diameters uniform in the thermocompression bonding step.

As described above, even if the wire diameters of the plurality of metal wires 20d1 and 20d2 are different, the intermetallic compound layers 24d1 and 24d2 can be reliably formed.

[others]
Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments.

For example, a columnar metal terminal and a metal wire in a state where the metal wire is not entwined with the columnar metal terminal, that is, in a state where the metal wire does not have an intersection and is simply wound around the columnar metal terminal in a single layer. And may be metal-bonded.

Further, in the above embodiment, the case where the intermetallic compound layer 24 is formed of a first metal containing aluminum as a main component and a second metal containing copper as a main component is exemplified. Further, in the second modification, the case where the intermetallic compound layer 24b is formed of a first metal containing aluminum as a main component and a second metal containing nickel as a main component is exemplified. However, if the melting point of the first metal forming the metal wire is lower than the melting point of the second metal forming the columnar metal terminal, the main component of the first metal and the main component of the second metal are not limited to the above examples. .. Further, if the melting point of the first metal is lower than the melting point of the second metal, the difference may be less than 300 degrees.

In addition, there are also forms obtained by subjecting various modifications to the embodiments that can be conceived by those skilled in the art, and embodiments realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of the present invention. Included in the present invention.

1,1A, 1B, 1C, 1D terminals 10, 10a, 10b, 10c, 10d Columnar metal terminals 20, 20d1, 20d2 Metal wires 23, 23d1, 23d2 Intermetallic compounds 24, 24a, 24b, 24c, 24d1, 24d2 layer

Claims (6)

Polygonar columnar columnar metal terminals and
A metal wire wound around the columnar metal terminal is provided.
The melting point of the first metal forming the metal wire is lower than the melting point of the second metal forming the columnar metal terminal.
An intermetallic compound layer between the first metal and the second metal is provided at the interface between the metal wire and the columnar metal terminal .
The metal wire has at least one intersection tied to the columnar metal terminal.
The intersection is arranged on the side surface of the columnar metal terminal where the intermetallic compound layer is not formed.
Terminal. The terminal according to claim 1, wherein the melting point of the first metal is 300 degrees or more lower than the melting point of the second metal. The main component of the first metal is aluminum.
The terminal according to claim 2, wherein the main component of the second metal is copper. The terminal according to any one of claims 1 to 3, wherein the thickness of the intermetallic compound layer is 5 μm or less. The terminal according to any one of claims 1 to 4 , wherein a plurality of the metal wires are provided, and each of them is wound around the columnar metal terminal. The terminal according to claim 5 , wherein the plurality of metal wires have different wire diameters.

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