JP2022136634A - Bonding structure for conductors and ultrasonic bonding method for conductors - Google Patents

Abstract

To provide a bonding structure for conductors and an ultrasonic bonding method for conductors that can suppress generation of burrs and perform ultrasonic bonding of conductors.SOLUTION: A conductor 15 is formed by intertwisting a plurality of wires. In order to perform ultrasonic bonding, first, an aggregate obtained by aggregating conductors 15a, 15b of a plurality of electric wires is arranged between an anvil 7 and a hone 5 opposite in a vertical direction. Gathers 9 are arranged on both sides of the aggregate of the conductors 15a, 15b. Subsequently, with the gathers 9 sandwiching and regulating the aggregate in a width direction, ultrasonic vibration is applied to the aggregate from the hone 5 while the aggregate is sandwiched by the anvil 7 and the hone 5 in the vertical direction and is collectively applied with a pressure. In this case, a diameter of a wire 19a arranged at an alignment part of the anvil 7 and the gather 9 and a wire 19b arranged at an alignment part of the hone 5 and the gather 9 is greater than a diameter of at least some wires 19b arranged in another parts.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a conductor bonding structure in which conductors of a plurality of electric wires are ultrasonically bonded together, and a conductor ultrasonic bonding method.

A wire harness used in an automobile or the like is used by joining a plurality of electric wires. For joining such electric wires, for example, the insulation coating of each of a plurality of electric wires is peeled off to expose the core wire, the tips of the core wires are aligned and overlapped, and in this state, the core wires are sandwiched. Thus, there is a method of joining core wires together by ultrasonic joining or the like (for example, Patent Document 1).

International Publication 2019/225492

FIG. 5(a) is a schematic diagram showing a general ultrasonic bonding apparatus 100. FIG. The ultrasonic bonding apparatus 100 mainly includes a horn 105, an anvil 107, gathers 109, and the like. The horn 105 arranged to face the anvil 107 is connected to a vibration source (not shown).

A plurality of conductors 111 are positioned between anvil 107 and horn 105 . Gathers 109 are arranged on both sides of the plurality of conductors 111 . In addition, the conductor 111 is configured by, for example, twisting a plurality of strands.

Next, as shown in FIG. 5B, with the conductor 111 placed on the anvil 107, both sides of the conductor 111 are sandwiched by the gathers 109, and the horn 105 is lowered from above to sandwich the conductor 111. In this state, while pressing the conductor 111 from above by the horn 105 (arrow X in the drawing), the horn 105 applies ultrasonic vibrations to the conductors 111, thereby joining the conductors 111 to form a joint 113. be.

However, since the horn 105 and the gathers 109 are movable, it is difficult to completely zero the clearance between the horn 105 and the gathers 109 and between the gathers 109 and the anvil 107 . FIG. 6 is an enlarged conceptual diagram of the Y portion of FIG. 5(b). As shown, for example, a predetermined clearance 115 is formed between the horn 105 and the gathers 109 . On the other hand, as described above, the conductor is deformed during ultrasonic bonding because the conductor is compressed. Therefore, part of the conductor enters the clearance 115, which causes so-called burrs.

The present invention has been made in view of such problems, and aims to provide a conductor bonding structure and a conductor ultrasonic bonding method capable of ultrasonically bonding conductors while suppressing the generation of burrs. aim.

In order to achieve the above-mentioned object, a first invention is a conductor joint structure in which conductors of a plurality of electric wires are ultrasonically welded to each other, wherein the conductors of the electric wire are composed of a plurality of strands, and a plurality of conductors are formed. At least the diameter of the strands arranged at the position corresponding to the mating part of the mold is larger than the diameter of at least part of the strands of the other parts in the joints that are gathered and joined. It is a joint structure of a conductor that

The joint portion has a substantially rectangular cross-section perpendicular to the axial direction of the electric wire, and the wire diameters of the wires positioned at least at four corners of the joint portion are larger than the diameters of the wire wires in at least part of other portions. may

A diameter of the wire positioned at the outer peripheral portion of the joint portion may be larger than a diameter of at least a portion of the wire positioned inside.

The electric wire may be made of a conductor whose main component is aluminum.

According to the first invention, by arranging the wire having a relatively large diameter at the portion corresponding to the mating portion of the molds, even if the wire is deformed during ultrasonic bonding, the molds are not separated from each other. It is difficult for part of the wire to enter the clearance of Therefore, it is possible to suppress the generation of burrs.

For example, in the case of a joint with a substantially rectangular cross section, the mating parts of the mold are generally near the four corners. , the occurrence of burrs can be suppressed.

In addition, by arranging wires having a relatively large diameter over the entire circumference of the joint portion, it is possible to more reliably suppress the occurrence of burrs.

In addition, especially in a conductor whose main component is aluminum, the conductor is easily deformed, so that a part of the wire tends to enter the clearance and burrs are likely to occur. Therefore, a greater effect can be obtained in the case of an electric wire made of a conductor whose main component is aluminum.

A second invention is a method for ultrasonically joining conductors of a plurality of electric wires, in which an anvil, a horn arranged to face the anvil, and a direction orthogonal to the facing direction of the anvil and the horn face each other. Using a pair of gathers, an assembly in which a plurality of conductors are assembled is sandwiched between the anvil, the horn, and the gathers, and is placed at the joining portion of the anvil and the gathers when applying vibration while applying pressure. and a diameter of the wire arranged at the joining portion of the horn and the gather are larger than diameters of at least some of the wires arranged at other portions. It is a method of ultrasonic bonding of conductors.

The diameter of the wire arranged at the joint portion of the anvil and the gather is 1.5 times or more the clearance between the anvil and the gather, and the wire arranged at the joint portion of the horn and the gather. It is desirable that the diameter of the wire is 1.5 times or more the clearance between the horn and the gather.

According to the second invention, by arranging the wire having a relatively large diameter in the portion corresponding to the mating portion of the mold, it is difficult for part of the wire to enter the clearance between the molds, and burrs are formed. The occurrence can be suppressed.

Such an effect can be obtained more reliably by setting the wire diameter to 1.5 times or more the clearance.

ADVANTAGE OF THE INVENTION According to this invention, the joining structure of a conductor and the ultrasonic joining method of a conductor which can suppress generation|occurrence|production of a burr and can ultrasonically join conductors can be provided.

The figure which shows the joining structure 10. FIG. (a) is a figure which shows the joining method of the conductor 15, (b) is an enlarged view of the conductor 15a, (c) is an enlarged view of the conductor 15b. (a) is a diagram showing the arrangement of the wires 19a at the time of joining, and (b) is an enlarged view of the C portion of (a). The figure which shows the state to which the conductor was joined. (a) and (b) are diagrams showing a conventional bonding method of a conductor 111. FIG. FIG. 2 is a conceptual diagram showing a conventional joint 113;

A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a junction structure 10. As shown in FIG. The joint structure 10 is obtained by ultrasonically joining conductors 15 of a plurality of electric wires 17 to each other. The electric wire 17 is configured by covering the outer periphery of the conductor 15 with an insulating coating. A predetermined range of insulation coating is removed from the end of the electric wire 17 to expose the inner conductor 15 . The conductor 15 is configured by twisting a plurality of strands. Although the details will be described later, there are conductors (electric wires) made of wires with a relatively large diameter and conductors (electric wires) made of wires with a relatively small diameter.

Materials such as aluminum (aluminum or aluminum alloy) and copper (copper or copper alloy) can be applied to the conductor 15 of the electric wire 17, but aluminum (so-called pure aluminum) is the main component of the conductor 15. Electric wire 17 is desirable. For example, in the case of the aluminum-based conductor 15, since it is relatively softer than a copper-based material, it is easily deformed and burrs are likely to occur. Therefore, this embodiment is particularly effective for aluminum (especially pure aluminum-based) materials.

The conductors 15 of the plurality of electric wires 17 are arranged in the same direction, and the joints 13 are formed by ultrasonically joining the conductors 15 to each other at the distal ends of the conductors 15 . That is, the conductor 15 is integrated at the joint 13 . Note that the directions of the electric wires 17 do not necessarily have to be the same.

Next, a method for ultrasonically bonding the conductors 15 of the electric wires 17 using an ultrasonic bonding apparatus will be described. FIG. 2(a) is a diagram showing an ultrasonic bonding apparatus 1 for forming conductors by ultrasonic bonding. The ultrasonic bonding apparatus 1 has an anvil 7 , a horn 5 arranged to face the anvil 7 , and a pair of gathers 9 facing each other in a direction perpendicular to the facing direction of the anvil 7 and the horn 5 . A vibration source that vibrates the horn 5 is omitted from the drawing.

Here, as described above, in the present embodiment, the plurality of conductors 15 are composed of the conductors 15a having relatively large wire diameters and the conductors 15a having relatively large wire diameters. FIG. 2(b) is a diagram showing the conductor 15a, and FIG. 2(c) is a diagram showing the conductor 15b.

The conductor 15a is configured by twisting a plurality of strands 19a. The diameter of the wire 19a at this time is defined as D1. Similarly, the conductor 15b is configured by twisting a plurality of strands 19b. The diameter of the wire 19b at this time is defined as D2. At this time, the relationship is D1>D2. In addition, it is desirable that the wire 19a having a relatively large diameter is, for example, 0.45 mm or more. Moreover, the number of strands of the conductors 15a and 15b is not limited to the illustrated example, and the number of strands may be different between the conductors 15a and 15b.

In order to perform ultrasonic bonding, first, an assembly in which the conductors 15a and 15b of a plurality of electric wires 17 are assembled is arranged between the anvil 7 and the horn 5 facing each other in the vertical direction. Also, gathers 9 are arranged on both sides of the aggregate of the conductors 15a and 15b. That is, the assembly of the conductors 15a and 15b is sandwiched between the anvil 7 and the horn 5 in the vertical direction, and sandwiched between the pair of gathers 9 in the width direction.

Next, in a state in which the width direction of the aggregate is sandwiched and regulated by the gathers 9, as shown in FIG. (in the direction of arrow A in the figure), ultrasonic vibration is applied from the horn 5 to the assembly.

At this time, the wires 19a are arranged at the mating portion of the anvil 7 and the gathers 9 and the mating portion of the horn 5 and the gathers 9. As shown in FIG. Moreover, the wire 19b is not arranged at the joining portion of the anvil 7 and the gathers 9 and the joining portion of the horn 5 and the gathers 9, but is arranged at other portions. That is, the wire diameter (D1 in FIG. 2B) of the wire 19a arranged at the joint between the anvil 7 and the gather 9 and the wire 19b arranged at the joint between the horn 5 and the gather 9 is different from the other. is larger than the diameter (D2 in FIG. 2(c)) of at least some of the strands 19b arranged in the portion of . In the following description, the mating portion between the anvil 7 and the gathers 9 and the mating portion between the horn 5 and the gathers 9 may simply be referred to as mating portions of the mold.

In this way, when forming the aggregate of the conductors 15a and 15b, the aggregate is formed in advance so that the wire having a relatively large wire diameter is positioned at the position corresponding to the mating portion of the mold. .

FIG.3(b) is a C section enlarged view of Fig.3 (a). As described above, clearance 21 is formed between horn 5 and gathers 9 . Although illustration is omitted, a predetermined clearance is similarly formed between the anvil 7 and the gathers 9 . That is, a clearance is formed at the mating portion of the mold.

Here, the diameter (D1 in FIG. 2B) of the wire 19a arranged at the mating portion of the horn 5 and the gathers 9 corresponds to the clearance 21 (E in FIG. 3B) between the horn 5 and the gathers 9. is preferably 1.5 times or more. Similarly, it is desirable that the diameter of the wires 19a arranged at the joining portion between the anvil 7 and the gathers 9 is 1.5 times or more the clearance between the anvil 7 and the gathers 9. As described above, the larger the diameter of the wires with respect to the clearance, the less likely burrs are generated when the wires are compressed and ultrasonically bonded.

In FIG. 4, while the anvil 7 and the horn 5 sandwich the conductor aggregate from the top and bottom and pressurize it collectively (in the direction of the arrow A in the figure), the horn 5 applies ultrasonic vibration to the aggregate, so that a plurality of is a diagram showing a joint portion 13 in which the conductors of are gathered and joined.

Here, by observing the end face of the joint 13, it is possible to grasp the boundaries between the strands (that is, the shape of each strand after compression). Also, the mating portion of the mold can be grasped as a trace of the mating portion of the mold from the outer peripheral surface of the joint portion.

Therefore, from the joining portion 13, it is possible to grasp which part is the mating portion of the mold, where the wires 19a and 19b are located, and the shape of each wire after joining. Therefore, by checking the joint portion 13, at least the diameter of the wire arranged at the position corresponding to the mating portion of the mold is larger than the diameter of at least part of the wire in the other portion. can be grasped.

For example, when the cross section of the joint 13 in the direction perpendicular to the axial direction of the electric wire is substantially rectangular as shown in the figure, the mating portions of the mold are often positioned at the four corners of the joint 13. . Therefore, in this case, it is desirable that the diameter of the wires positioned at least at the four corners of the joint portion 13 is larger than the diameter of the wires positioned at least part of the other portions.

As described above, if the wire 19a having a relatively large diameter can be arranged only at the mating portion of the mold, the wires 19a and 19b may be mixed in other portions. For example, the wire 19b having a relatively small diameter may be arranged so as to be adjacent to the wire 19a arranged at the mating portion of the mold.

On the other hand, at the stage of compressing and applying vibration to an assembly of conductors (strands), there is a risk that the positions of the strands will be displaced from the mating portion of the mold. For this reason, it is desirable to arrange the wires 19a having a relatively large diameter around the entire outer periphery of the assembly, and arrange the wires 19b having a relatively small diameter inside. In other words, it is desirable to arrange the wire 19b so as to cover the outer circumference of the wire 19b with the wire 19a.

By doing so, the diameter of the wires 19a positioned all around the outer periphery of the joint 13 after ultrasonic bonding is larger than the diameter of at least a part of the wires 19b positioned inside. That is, the wire 19b does not come into contact with the mold, and even if part of the wire 19a on the outer periphery moves during compression, the wire 19b is prevented from being arranged in the mating portion of the mold. can do.

As described above, the conductors 15 (15a, 15b) are joined together to form the joining portion 13 .

As described above, according to the present embodiment, when forming an aggregate of conductors (strands), strands 19a having a large strand diameter are arranged in advance at a portion corresponding to the mating portion of the mold. Therefore, it is possible to prevent part of the wire from entering the clearance between the molds. Therefore, it is possible to suppress the generation of burrs.

In the above description, an example in which two types of conductors 15a and 15b with different wire diameters are assembled to form the joint portion 13 has been described, but conductors with three or more wire diameters may be mixed. . In this case, at least the wire with the smallest diameter is formed into the assembly so as not to be positioned at the mating portion of the mold.

For example, when three types of conductors with different wire diameters are assembled, the wire with the second largest wire diameter may be placed in the mating portion of the mold, and more preferably, the wire with the largest wire diameter. The wire may be placed in the mating portion of the mold.

Ultrasonic bonding was performed using a conductor assembly in which wires with different wire diameters were arranged in the mating part of the mold, and the generation of burrs was evaluated. The horn-to-gather clearance and the anvil-to-gather clearance were both about 0.3 mm. A pure aluminum-based conductor was used.

In the assembly of conductors, when a wire with a wire diameter of 0.45 mm and a wire with a wire diameter of 0.29 mm are arranged at the position corresponding to the mating part of the mold, The presence or absence of burrs after sonic bonding was evaluated. As a result, no burrs were found with a wire diameter of 0.45 mm (that is, 1.5 times or more the clearance). On the other hand, in the wire having a wire diameter of 0.29 mm, part of the wire entered the clearance and burrs were generated.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical scope of the present invention is not influenced by the above-described embodiments. It is obvious that a person skilled in the art can conceive various modifications or modifications within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. be understood to belong to

For example, the number and arrangement of electric wires are not limited to the example shown in the figure, such as the number of strands constituting a conductor.

Reference Signs List 1: Ultrasonic bonding device 5: Horn 7: Anvil 9: Gather 10: Bonding structure 13: Joint portions 15, 15a, 15b: Conductor 17: Electric wire 19a , 19b . clearance

Claims (6)

A conductor joint structure in which conductors of a plurality of electric wires are ultrasonically joined together,
The conductor of the electric wire is composed of a plurality of strands,
In a joint where a plurality of conductors are assembled and joined, at least the diameter of the wire arranged at the position corresponding to the mating part of the mold is larger than the diameter of at least part of the wire in other parts A conductor junction structure characterized by being large. The joint portion has a substantially rectangular cross-section perpendicular to the axial direction of the electric wire, and the wire diameters of the wires located at least at four corners of the joint portion are larger than the diameters of the wire wires in at least part of other portions. 2. The conductor joint structure according to claim 1, wherein: 3. The conductor joint structure according to claim 1, wherein the diameter of the wires located in the outer peripheral portion of the joint portion is larger than the diameter of at least a part of the wires located inside. 4. The conductor joint structure according to claim 1, wherein the electric wire is made of a conductor whose main component is aluminum. An ultrasonic bonding method between conductors of a plurality of electric wires,
Using an anvil, a horn arranged to face the anvil, and a pair of gathers facing in a direction perpendicular to the facing direction of the anvil and the horn,
The diameter of the wire arranged at the joining portion of the anvil and the gather when an assembly of a plurality of conductors is sandwiched between the anvil, the horn, and the gather and is subjected to vibration while being pressurized. , a method for ultrasonically bonding a conductor, wherein the diameter of the wires arranged at the mating portion of the horn and the gather is larger than the diameter of at least a part of the wires arranged at other portions. . The diameter of the wire arranged at the joint portion of the anvil and the gather is 1.5 times or more the clearance between the anvil and the gather, and the wire arranged at the joint portion of the horn and the gather. 6. The method for ultrasonically bonding conductors according to claim 5, wherein the diameter of the wire is 1.5 times or more the clearance between the horn and the gather.

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