WO2024185001A1 - Flexible conductor and electrical apparatus - Google Patents

Abstract

The present invention provides a flexible conductor comprising a plurality of copper foils layered in the thickness direction, the flexible conductor having low electrical resistance as a result of the layered plurality of copper foils being ultrasonically bonded to each other at both ends in the copper foil extension direction. The present invention also provides an electrical apparatus comprising the flexible conductor, a movable part fastened to a first end out of first and second ends of the flexible conductor, and a terminal to which the second end is fastened.

Description

Flexible conductors and electrical equipment

The present disclosure relates to ultrasonically bonded flexible conductors and electrical devices including the flexible conductors.

　Prior art discloses a flexible conductor that has a conductive and flexible flexible portion formed by stacking multiple thin copper plates, and terminal portions provided at both ends of the flexible portion, and that in manufacturing this flexible conductor, the thin plates are tin-plated, and the tin plating is melted by resistance welding or the like to join the stacked thin plates (for example, Patent Document 1).

JP 2013-131434 A

However, in conventional bonding methods in which the tin plating is melted to bond stacked copper foils, bonding is performed via the plating layer. This means that when electricity is passed through the tin plating layer, current flows through the tin plating layer, which has a higher electrical resistance than copper, resulting in an issue of increased electrical resistance compared to a flexible conductor made of copper foil without tin plating.

The present disclosure has been made to solve the problems described above, and aims to provide a flexible conductor in which multiple copper foils are ultrasonically bonded, and an electrical device equipped with the flexible conductor.

The flexible conductor disclosed herein comprises multiple copper foils stacked in the thickness direction, and the multiple copper foils are ultrasonically bonded to each other at both ends in the extension direction of the copper foil.

The electrical device according to the present disclosure includes the above-mentioned flexible conductor, and of the first and second ends of the flexible conductor, a movable part that is fastened to the first end and a terminal to which the second end is fastened.

The flexible conductor according to the present disclosure can provide a flexible conductor with a low electrical resistance value when current is applied, compared to conventional flexible conductors in which laminated copper foils are joined by tin plating. In addition, the electrical device according to the present disclosure can provide an electrical device with a low electrical resistance value.

1 is a schematic side view showing a state in which a switch including a flexible conductor according to a first embodiment of the present disclosure is in an open state. 1 is a schematic side view showing a state in which a switch including a flexible conductor according to a first embodiment of the present disclosure is closed; FIG. 1 is a perspective view of a flexible conductor according to a first embodiment of the present disclosure. FIG. 11 is a perspective view of a flexible conductor according to a second embodiment of the present disclosure. FIG. 11 is a perspective view of a flexible conductor according to a third embodiment of the present disclosure. 6 is a schematic diagram of a flexible conductor according to a third embodiment of the present disclosure, corresponding to a cross section taken along line AA' in FIG. 5.

Below, an embodiment of the present disclosure will be described with reference to the attached drawings. Note that the drawings are schematic, and the interrelationships of sizes and positions shown in different drawings are not necessarily described accurately and may be changed as appropriate. In the following description, similar components are illustrated with the same reference numerals, and their names and functions are the same or similar. Therefore, detailed descriptions thereof may be omitted.

Embodiment 1.
The flexible conductor 1 in the first embodiment will be described with reference to Figures 1, 2 and 3. Figure 1 is a schematic side view showing a state in which a switch 11 including the flexible conductor 1 in the first embodiment is in an open state, that is, a state in which a movable contact 4 and a fixed contact 5, which will be described later, are not in contact with each other. For the sake of convenience, in Figure 1, a part of the front surface of the vacuum interrupter 16 is omitted to show the inside of the vacuum interrupter 16.

As shown in FIG. 1, the switch 11 according to this embodiment includes a flexible conductor 1, a first terminal 12 (a fixed terminal on the flexible conductor side electrically connected to the movable contact 4 via the flexible conductor 1), a driving device tip 13, a first movable part 14 (a movable part connected to the movable contact 4), a vacuum valve 16, a fixed part 17 (a movable part connected to the fixed contact 5), a second terminal 19 (a fixed terminal on the vacuum valve side electrically connected to the fixed contact 5), a bolt 20 and a nut 23 that fix the first terminal 12 and the flexible conductor 1, a bolt 21 that fixes the fixed part 17 and the second terminal 19, and a nut 22 that fixes the first movable part 14, the flexible conductor 1, and the driving device tip 13. The switch 11 includes the fixed contact 5 and the fixed part 17 as fixed members, and the movable contact 4 and the first movable part 14 as movable parts.

The flexible conductor 1 includes a flexible part 38 having electrical conductivity and flexibility, a first end 32, and a second end 33. The first end 32 and the second end 33 are located so as to sandwich both ends of the flexible part 38. Here, the first end 32 and the second end 33 may be a part on one end side or the other end side of the flexible part 38. In other words, the first end 32 and the second end 33 of the flexible conductor 1 are not limited to edges, etc., but may be a part excluding the flexible part 38. For example, if the flexible part 38 is not in the center of the flexible conductor 1 but is located off-center, one end may be the central part of the flexible conductor 1.

The first end 32 of the flexible conductor 1 is fastened to the driving device tip 13 and the first movable part 14, for example, by a nut 22. That is, the first end 32 of the flexible conductor 1 is connected to the movable part of the switch 11. That is, the first end 32 of the flexible conductor 1 is electrically connected to the first movable part 14.

The first end 32 of the flexible conductor 1 only needs to be connected to the first movable part 14, and does not have to be connected to the tip 13 of the driving device.

The drive device tip 13 and the first movable part 14 are fastened together with a nut 22.

The driving device tip 13 is connected to an external driving device (not shown). The driving device is driven, for example, by spring force. The driving device includes an insulating rod connected to the first movable part 14.

The second end 33 of the flexible conductor 1 is fastened to the first terminal 12, for example, by a bolt 20 and a nut 23. That is, the second end 33 of the flexible conductor 1 of the switch 11 is connected to the fixed part of the switch 11. In addition, the second end 33 of the flexible conductor 1 is electrically connected to the first terminal 12.

In addition, the first end 32 and the second end 33 that are coupled to the driving device tip 13, the first movable part 14, and the first terminal 12 as the mating members do not refer only to the outer periphery or the end of the flexible conductor 1, and the part that is coupled to the mating member may be located closer to the center than the outer periphery of the flexible conductor 1.

The fixed portion 17 and the second terminal 19 are fastened with a bolt 21. In addition, the fixed portion 17 and the second terminal 19 are electrically connected.

FIG. 2 is a schematic side view showing the state in which the switch 11 including the flexible conductor 1 of embodiment 1 is closed, i.e., the state in which the movable contact 4 and the fixed contact 5 are in contact. For ease of explanation, FIG. 2 omits part of the front of the vacuum valve 16 to show the inside of the vacuum valve 16. In FIG. 2, the same reference numerals as in FIG. 1 indicate the same configuration, and therefore explanations are omitted.

As shown in Figure 2, the movable contact 4 and the fixed contact 5 in the vacuum valve 16 are in contact. In other words, the electrical circuit of the switch 11 is in a closed state.

The driving device transmits power to the driving device tip 13 to move in the direction of the arrow shown in FIG. 2. When power is transmitted to the driving device tip 13, the power is transmitted to the first movable part 14 connected to the driving device tip 13.

When power is transmitted from the drive tip 13 to the first movable part 14, the movable contact 4 moves in a direction approaching the fixed contact 5. As the movable contact 4 moves, the movable contact 4 and the fixed contact 5 come into contact, and the switch 11 in the open state shown in Figure 1 transitions to the switch 11 in the closed state shown in Figure 2.

The flexible conductor 1 follows the movement of the first movable part 14 when the switch 11 transitions from an open state to a closed state and from a closed state to an open state.

The switch 11 to which the flexible conductor 1 of the present invention is applied is not limited to a circuit breaker that uses a vacuum valve, but may be other electrical equipment such as a disconnector in which a fixed part and a movable part are electrically connected. The flexible conductor 1 can be easily adapted for use in switches and other electrical equipment having a different configuration from the switch 11 of this embodiment.

FIG. 3 is a perspective view of the flexible conductor 1 according to embodiment 1.

The flexible conductor 1 has multiple copper foils 41 stacked in the thickness direction. The multiple copper foils 41 are, for example, rectangular with long and short sides. The thickness of the copper foils 41 is, for example, about 0.1 mm.

The flexible conductor 1 also includes ultrasonic joints 34, fastening surfaces 35, and fastening holes 36. For example, the ultrasonic joints 34 are located at both ends of the multiple copper foils 41 in the long side direction.

As shown in FIG. 3, among the multiple copper foils 41 included in the flexible conductor 1, the outermost copper foil 42 has a fastening surface 35 for fastening to a mating member on a surface different from the laminated surface, i.e., when the multiple copper foils 41 are laminated, the surface different from the laminated surfaces of the two copper foils located on the outermost sides in the lamination direction. Hereinafter, the fastening surface is referred to as the surface of the surface layer excluding the flexible portion 38, rather than the entire surface of the surface layer of the flexible conductor 1. The area where the flexible conductor 1 is fastened to the mating member may be a part of the fastening surface 35, and may be in contact with the first movable portion 14 at the fastening area 37 shown in FIG. 3, for example.

In the ultrasonic joint 34 of the flexible conductor 1, multiple stacked copper foils 41 are ultrasonically joined to each other. The ultrasonic joint 34 refers to the portion where multiple stacked copper foils 41 are ultrasonically joined to each other.

As shown in FIG. 3, in the flexible conductor 1 according to this embodiment, the ultrasonic joints 34 are located on the fastening surface 35 at locations that correspond to the four corners of the copper foil 41.

The x marks in Figure 3 are processing marks that occur on the conductor surface during ultrasonic bonding. The processing marks occur at the position clamped between the horn and anvil of the equipment that performs the ultrasonic bonding. Figure 3 shows a case where there are three processing marks at each of the four corners of the copper foil 41 where the ultrasonic bonding portion 34 is located, but the number of processing marks is not limited to three.

Furthermore, the location of the ultrasonic joints 34 is not limited to the four corners of the copper foil 41, as long as the location does not impair the flexibility of the flexible conductor 1.

Furthermore, the ultrasonic bonding portion 34 where ultrasonic bonding is performed is not limited to the outer periphery of the flexible conductor 1 as shown in FIG. 4, but may be provided in the center, such as a portion adjacent to the fastening hole 36. It may also be provided in a portion other than the fastening region 37.

When ultrasonic bonding is performed on the ultrasonic bonding portion 34 of the flexible conductor 1, ultrasonic vibrations are applied to the copper foil 41, so that adjacent copper foils 41 are bonded together and integrated.

The ultrasonic joint 34 of the flexible conductor 1 is joined to integrate the multiple copper foils 41 in the thickness direction, so that when attaching the flexible conductor 1 to the movable part or terminal, the flexible conductor 1 can be easily electrically connected to the drive device tip 13 of the switch 11, the first movable part 14, the first terminal 12, etc., without the copper foils 41 coming apart.

In parts of the flexible conductor 1 other than the ultrasonic joint 34, the copper foils 41 are not joined to each other. Because the copper foils 41 are not joined to each other, the copper foils 41 can bend freely, and the flexible conductor 1 can follow the movement of the first movable part 14.

The multiple copper foils 41 of the flexible conductor 1 are preferably ultrasonically bonded to one another in the area corresponding to the fastening surface 35. It is also desirable that the ultrasonic bonded portion 34 at least partially overlaps with the area corresponding to the fastening region 37. The area corresponding to the fastening surface 35 refers to the area of the copper foil 41 onto which the fastening surface 35 is projected in the thickness direction of the flexible conductor 1.

By performing ultrasonic bonding on the ultrasonic bonding portion 34 that overlaps at least a portion of the fastening region 37, the bonding at the ultrasonic bonding portion 34 can suppress contact resistance by pressing the fastening region 37 when attaching the flexible conductor 1 in addition to the bonding by ultrasonic bonding, and can lower the electrical resistance compared to a simple ultrasonic bond.

Ultrasonic bonding can solid-phase bond the copper foils together. The flexible conductor 1 according to this embodiment is bonded by ultrasonic bonding while the copper foils are still in their original state. This means that unlike methods such as spot welding, which melt the tin plating to bond the copper foils, there is no need to plate the copper foils 41 with tin or other metals for bonding.

In this way, by directly joining the copper foils 41 together without using tin plating, which has a higher electrical resistance than copper foil, the electrical resistance of the flexible conductor 1 can be made lower than that of a flexible conductor connected by conventional plating. Therefore, when creating a flexible conductor with the same resistance, the number of copper foils 41 that form the flexible conductor 1 can be reduced compared to a flexible conductor that uses tin plating.

In addition, since each copper foil 41 is not plated, the process of plating the copper foil 41 can be omitted, thereby reducing manufacturing costs.

There is also a method of spot welding the base copper foil to create a flexible conductor, but because copper melts at high temperatures, an oxide film forms on the surface, which must be removed. With ultrasonic bonding, bonding occurs in a solid state, so bonding can be done below the melting point of the base material, such as copper, and no oxide film is formed.

In addition, in the ultrasonic bonding portion 34, it is preferable that the laminated copper foil 41 is ultrasonically bonded without a plated layer, but some layers may be bonded through a plated layer.

As shown in FIG. 3, the flexible conductor 1 has a fastening hole 36 on the fastening surface 35. The flexible conductor 1 is fastened to the mating member through the fastening hole 36. When fastening, a bolt 20, a nut 22, and a nut 23 are used. When the flexible conductor 1 is fastened to the mating member through the fastening hole 36, fastening is not limited to using a bolt and a nut, and may be performed by means of fitting, welding, or the like.

The flexible conductor 1 having the fastening hole 36 makes it easier to use it in switches and other electrical equipment other than the switch 11 of this embodiment, compared to when the flexible conductor 1 does not have the fastening hole 36.

Fastening holes 36 do not have to be provided.

Next, we will explain the manufacturing method of the switch 11 of this embodiment.

First, prepare the flexible conductor 1 of embodiment 1, i.e., the flexible conductor 1 in which each layer is ultrasonically bonded to each other, the vacuum valve 16, and the switch 11 to which the vacuum valve is attached (excluding the vacuum valve 16, the flexible conductor 1, etc.). The ultrasonically bonded flexible conductor 1 can be manufactured by applying ultrasonic vibrations between the copper foils 41 stacked in the thickness direction. The manufacturing method of the flexible conductor 1 will be described in detail later.

Next, the vacuum valve 16 is attached to the switch 11, and then the flexible conductor 1 is attached to the first movable part 14 (movable electrode rod) connected to the vacuum valve 16. The first movable part 14 is attached to the first movable part 14 through the fastening hole 36 of the flexible conductor 1 so that the first movable part 14 passes through the fastening hole 36, and the first movable part 14 and the flexible conductor 1 are joined. At this time, each copper foil 41 of the flexible conductor 1 is ultrasonically bonded at the ultrasonic bonding part 34, and each copper foil 41 does not come apart, so it can be easily attached to the first movable part 14. The first movable part 14 and the flexible conductor 1 can be attached by fastening with a nut. The first movable part 14 and the flexible conductor 1 can be attached by other methods such as fitting, without being limited to fastening with a nut.

Next, the flexible conductor 1 is attached to the first terminal 12. The fastening hole of the first terminal 12 is aligned with the fastening hole 36 of the flexible conductor 1, and the flexible conductor 1 is attached by fastening the flexible conductor 1 with a nut 23 through a bolt 20. The method of attaching the first movable part 14 and the flexible conductor 1 is not limited to fastening with a bolt, and other methods such as fitting may also be used.

The order of attachment is not limited to the above, and the order of attachment may be changed as appropriate, for example by previously connecting a part of the flexible conductor 1 before attaching the vacuum valve 16 to the switch 11. Also, while the method of manufacturing the switch 11 having the vacuum valve 16 has been described here, other electrical devices such as disconnectors can be manufactured in a similar manner.

Embodiment 2.
The flexible conductor 2 in the second embodiment will be described with reference to Fig. 4. Description of the same configuration as in the first embodiment will be omitted. In Fig. 4, the same reference numerals as in Figs. 1 to 3 indicate the same or corresponding parts.

FIG. 4 is a perspective view of the flexible conductor 2 according to the second embodiment. As shown in FIG. 4, the flexible conductor 2 of this embodiment differs from the flexible conductor 1 of the first embodiment in the position of the ultrasonic joint 34. The following will focus on the differences from the flexible conductor 1 of the first embodiment.

As shown in FIG. 4, in the flexible conductor 2 according to this embodiment, the ultrasonic joint 34 is located in a range of the fastening surface 35 that includes the fastening hole 36. In other words, the ultrasonic joint 34 is included in the fastening surface 35. Note that the ultrasonic joint 34 and the fastening surface 35 may partially overlap.

In this way, the ultrasonic joint 34 may be provided in a portion adjacent to the fastening hole 36. By ultrasonically joining the portion adjacent to the fastening hole 36, when the flexible conductor 2 is attached and fastened with a bolt or nut, pressure is applied, making the contact stronger and further reducing the contact resistance.

By performing ultrasonic bonding in an area including the fastening holes 36, which are the current path, the copper foils 41 in the current path are firmly bonded together. By firmly bonding the copper foils 41 together, the electrical resistance of the flexible conductor 2 can be reduced compared to when the copper foils 41 are fastened with bolts and nuts. Furthermore, if there is no need to reduce the electrical resistance of the flexible conductor 2, the number of copper foils 41 that form the flexible conductor 2 can be reduced.

The x marks in Figure 4 are processing marks that occur on the conductor surface during ultrasonic bonding. After ultrasonic bonding, processing marks remain on the fastening surface 35 that is fastened to the mating member, but since the processing marks are concave, they do not affect the contact with the mating member. The number of processing marks is not limited to the number shown in the figure. In addition, the arrangement pattern of the processing marks may be, for example, arranged in a grid pattern.

Embodiment 3.
The flexible conductor 3 in the third embodiment will be described with reference to Fig. 5 and Fig. 6. Description of the same configuration as in the first embodiment will be omitted. In Fig. 5 and Fig. 6, the same reference numerals as in Figs. 1 to 4 indicate the same or corresponding parts.

FIG. 5 is a perspective view of the flexible conductor 3 according to the third embodiment. FIG. 6 is a schematic diagram of the flexible conductor 3 according to the third embodiment, corresponding to a cross section taken along line A-A' in FIG. 5. The flexible conductor 3 of this embodiment differs from the flexible conductor 1 of the first embodiment in that a plating layer is provided on the copper foil 42. The following will focus on the differences from the flexible conductor 1 of the first embodiment.

The flexible conductor 3 in this embodiment is located at the outermost position among the multiple copper foils 41, and the copper foil 42 that is fastened to the mating member has a plating layer of tin or the like on the side that is fastened to the mating member.

The plating layer may be provided over the entire side of the copper foil 42 that is fastened to the mating member, or, for example, only on the fastening surface 35.

When bare copper foil is exposed to oxygen for a long period of time, an oxide film forms on the surface. To prevent this from happening, it is possible to plate all of the copper foil.

If a plating that melts due to the frictional heat generated by ultrasonic bonding, such as tin plating, is used, the frictional heat generated between the copper foils 41 will cause the plating to melt before bonding is completed in the solid phase, causing slippage between the copper foils. Slippage will prevent the ultrasonic vibrations from being transmitted, resulting in poor bonding.

By providing a plating layer only on the side of the copper foil 42 that is fastened to the mating member, slippage between the copper foils 41 is suppressed, and poor bonding is prevented. In addition, because the ultrasonic bonding portion 34 of the copper foil 41 is firmly bonded, no oxide film is formed on the copper foil 41 that is bonded to other copper foils 41.

In addition, a plating layer may be provided on the entirety or part of the copper foil 41 located on the outermost side opposite the copper foil 42 that is fastened to the opposing member, opposite the fastening surface 35 of the copper foil 42.

It is also desirable to apply plating only to the side of the copper foil 42 that is fastened to the mating member, but a plating layer may be provided on a part of the side of the copper foil 42 that is not fastened to the mating member, or a plating layer may be provided on a part of the other copper foil 41.

For plating, it is recommended to use materials such as tin and silver that are suitable for the temperature during ultrasonic bonding.

In FIG. 6, ten sheets of copper foil 41 are shown, but the number of sheets of copper foil 41 is not limited to ten.

Next, a method for manufacturing a flexible conductor according to embodiments 1 to 3 will be described. The method for manufacturing a flexible conductor according to embodiments 1 to 3 includes step 101 of stacking multiple copper foils 41 in the thickness direction, and step 102 of ultrasonically joining the multiple stacked copper foils 41 to each other at both ends in the extension direction of the stacked copper foils 41.

Furthermore, the above step 102 of ultrasonically bonding the stacked copper foils 41 to each other may include step 102a of ultrasonically bonding the stacked copper foils 41 to each other on the fastening surface 35 of the flexible conductor.

Furthermore, the above step 102 of ultrasonically bonding the multiple stacked copper foils 41 to each other may include step 102b of ultrasonically bonding the multiple stacked copper foils 41 to each other at the corners of the stacked copper foils 41.

Furthermore, the manufacturing method of the flexible conductor according to the first to third embodiments includes step 103 of forming a plating layer on the fastening surface 35 of the copper foil 41, and step 103 of forming the plating layer may be performed before the above step 101, or between the above step 101 and the above steps 102, 102a, and 102b, or even after the above steps 102, 102a, and 102b.

In other words, to produce an ultrasonically bonded flexible conductor, the copper foil 41 laminated in the thickness direction is clamped between a horn and anvil attached to the ultrasonic bonding machine, and ultrasonic vibrations are transmitted to the copper foil 41 while applying pressure. In this way, the oxide film and dirt on the bonding interface are removed, and the crystal grains between each piece of copper foil 41 are brought close enough to the interatomic distance, allowing the copper foils 41 to be bonded together.

In addition, in each of the above embodiments described in this specification, the material, ingredients, dimensions, shape, relative positional relationship, implementation conditions, etc. of each component may be described, but these are examples in all aspects and each embodiment is not limited to what has been described. Therefore, countless modified examples not exemplified are expected within the scope of each embodiment. For example, this includes cases where any component is modified, added, or omitted, and even cases where at least one component in at least one embodiment is extracted and combined with a component of another embodiment.

1, 2, 3 Flexible conductor, 11 Switch, 12 First terminal, 14 First movable part, 16 Vacuum valve, 17 Fixed part, 32 First end, 33 Second end, 35 Fastening surface, 36 Fastening hole, 41, 42 Copper foil

Claims (6)

A plurality of copper foils are laminated in a thickness direction,
A flexible conductor in which a plurality of laminated copper foils are ultrasonically bonded to each other at both ends in the extending direction of the copper foils. Among the plurality of copper foils, the copper foil located at the outermost position has a fastening surface to be fastened to a mating member on a surface different from the surface on which the copper foil is laminated,
The flexible conductor according to claim 1 , wherein the plurality of laminated copper foils are ultrasonically bonded to each other between the plurality of copper foils and in the areas corresponding to the fastening surfaces. The flexible conductor according to claim 2, in which the multiple laminated copper foils are ultrasonically bonded to each other at the corners of the copper foil on the fastening surface. The flexible conductor according to any one of claims 2 to 3, having a plating layer on the fastening surface. A flexible conductor according to any one of claims 2 to 4, having a fastening hole on the fastening surface. A flexible conductor according to any one of claims 1 to 5;
a movable part fastened to the first end of the flexible conductor; and
a terminal to which the second end is fastened; and
Electrical equipment equipped with

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