Method for manufacturing a conductor connection structure

Abstract

To provide a method for manufacturing a conductor connection structure that includes a step of joining one end of an electric wire having a plurality of element wires gathered in a bundle to one end of a conductor formed in a plate shape, and can restrain the element wires from protruding when the electric wire and the conductor are joined.SOLUTION: A method for manufacturing a conductor connection structure includes a step of: preparing a conductor formed in a plate shape and an electric wire having a plurality of element wires gathered in a bundle, a step of texturing one end surface of the conductor, pressing one end portion of the electric wire against the textured surface of the conductor to temporarily join the electric wire and the conductor, and a step of welding the temporary joint portion between the electric wire and the conductor to join the electric wire and the conductor.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a conductor connection structure.

Background Art

[0002] Automobiles are equipped with a variety of electronic devices, and wire harnesses are routed to transmit power, control signals, etc. to the electronic devices. A wire harness includes a plurality of electric wires and connectors, and is connected to an electronic device or another wire harness by fitting the connector to the connector of the electronic device or the connector of another wire harness.

[0003] Generally, a wire with a terminal (a wire with a conductor) that constitutes such a wire harness includes an electric wire and a terminal fitting (a conductor) attached to the end of the electric wire (see Patent Document 1).

[0004] Patent Document 1 discloses a wire with a terminal including an electric wire in which a conductor portion made of a material mainly composed of a first metal is coated with an insulating material, and a terminal made of a material mainly composed of a second metal different from the first metal and connected to the conductor portion exposed at one end of the electric wire. In the wire with a terminal, an alloy layer containing the first metal and the second metal is formed across the conductor portion and the terminal on the entire outer peripheral edge of the contact portion between the conductor portion and the terminal. Specifically, in a state where the conductor portion including a plurality of strands and the terminal are butted against each other, the contact portion between the conductor portion and the terminal is melted and joined by a laser welder. The joint portion between the conductor portion and the terminal thus formed becomes an alloy layer, and the conductor portion and the terminal are electrically connected and firmly joined.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the wire with terminals described in Patent Document 1 has the following problems. For example, when a wire 18 having a plurality of strands 16 and a strand forming portion 14 in which the strands 16 are formed into a rectangular shape is abutted against the end face of a conductor 12 as shown in FIG. 7, the strand 14A tends to protrude outward from the strand forming portion 14. That is, while the end face of the conductor 12 is flat, since the strand forming portion 14 at the end of the wire 18 has the strands in a bundled state, when the end of the wire 18 is abutted against the end face of the conductor 12, the strand 14A will protrude outward. When the strand 14A protrudes outward, the tip of the sharp strand 14A may tear the protective tape or tube for insulation provided on the wire 18. In order to prevent this, measures such as forming the protective tape or tube provided on the wire 18 thick or cutting the protruding strand 14A are necessary.

[0007] The present invention has been made in view of the problems of such prior art. And the object of the present invention is to provide a method for manufacturing a conductor connection structure including a step of joining one end of a wire in which a plurality of strands are bundled together and one end of a conductor formed in a plate shape, and capable of suppressing the protrusion of the strands when joining the wire and the conductor.

Means for Solving the Problems

[0008] The method for manufacturing a conductor connection structure according to an aspect of the present invention includes a step of preparing a conductor formed in a plate shape and a wire in which a plurality of strands are bundled together, a step of performing uneven processing on one end face of the conductor, a step of pressing one end portion of the wire against the uneven processed surface of the conductor to temporarily join the wire and the conductor, and a step of welding the temporarily joined portion of the wire and the conductor to join the wire and the conductor.

Effects of the Invention

[0009] According to the present invention, in a method for manufacturing a conductor connection structure including a step of joining one end of an electric wire in which a plurality of strands are bundled together and one end of a conductor formed in a plate shape, a method for manufacturing a conductor connection structure capable of suppressing the protrusion of the strands when joining the electric wire and the conductor can be provided.

Brief Description of Drawings

[0010]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a method for manufacturing a conductor connection structure according to the present embodiment will be described in detail with reference to the drawings. Note that the dimensional ratios in the drawings are exaggerated for convenience of explanation and may be different from the actual ratios.

[0012] The manufacturing method of the conductor connection structure of this embodiment includes a step of preparing a conductor formed in a plate shape and an electric wire in which a plurality of strands are bundled together (hereinafter also referred to as "step A"). Further, it includes a step of performing uneven processing on one end face of the conductor (hereinafter also referred to as "step B"). Furthermore, it includes a step of pressing one end portion of the electric wire against the surface of the conductor on which the uneven processing has been performed to temporarily join the electric wire and the conductor (hereinafter also referred to as "step C"). Furthermore, it includes a step of welding the temporarily joined portion of the electric wire and the conductor to join the electric wire and the conductor (hereinafter also referred to as "step D").

[0013] In a wire with a conductor, when appropriately joining the wire and the conductor, it is ideal that both the joining part (end part) of the wire and the joining part (end part) of the conductor are completely flat. However, in reality, at least the end part of the wire is not flat because it is an aggregate of a plurality of strands, that is, in a bundled shape. Moreover, some of the plurality of strands may protrude to the outside, which may also cause problems as described above. Therefore, in the manufacturing method of the conductor connection structure of this embodiment, when the end part of the wire is pressed against the end face of the conductor, even if there are strands protruding to the outside, uneven processing is performed on the joining part of the plate-shaped conductor end face with the wire so that the protruding strands are absorbed. That is, in this embodiment, when the end part of the wire is butted against and pressed against the end face of the conductor with uneven processing, the strands protruding to the outside are pushed into the recesses formed by the uneven processing, so that the strands protruding to the outside can be suppressed. Therefore, it is possible to prevent tearing of the insulating protective tape, tube, etc. applied to the wire caused by the strands protruding to the outside. As a result, it is possible to reduce measures such as forming the protective tape, tube, etc. thicker or cutting the protruding strands. In addition, in this embodiment, it goes without saying that by butting and joining the conductor and the wire, it is possible to realize a space-saving connection compared to the form of overlapping and connecting the conductor and the wire, and improve the added value.

[0014] An example of the conductor connection structure obtained by the manufacturing method of the conductor connection structure of the present embodiment is shown in FIG. 1. The wire with a conductor (conductor connection structure) 10 shown in FIG. 1 is formed by joining a conductor 12 and a wire 18 in which a plurality of strands 16 are bundled together. One end of the wire 18 has a strand forming portion 14 in which the strands 16 are compression molded. The joint portion between the conductor 12 and the strand forming portion 14 forms a joint portion 20 formed by melting the conductor 12 and the strand forming portion 14 by welding. In this way, the interface between the conductor 12 and the strand forming portion 14 of the wire 18 consists of the joint portion 20, and the conductor 12 and the wire 18 are electrically connected and firmly joined. And, unlike the conventional one shown in FIG. 7, in the wire 10 with a conductor shown in FIG. 1, there is no or little situation where the strands jump out to the outside from the end of the strand forming portion 14. This is because when joining the conductor 12 and the strand forming portion 14 of the wire 18, the strands that jumped out to the outside were pushed into the recesses formed by the uneven processing. Hereinafter, each step of the manufacturing method of the conductor connection structure of the present embodiment will be described in detail.

[0015] [Step A] Step A is a step of preparing a conductor formed in a plate shape and a wire in which a plurality of strands are bundled together.

[0016] Examples of the conductor formed in a plate shape include a terminal, a bus bar, etc., which have a certain thickness and have a surface for joining with a wire at one end. The end face, which is one end of the conductor, is a portion for joining with a plurality of strands of the wire, and is a flat surface in the conductor prepared in Step A. Further, the conductor may be a laminated thin plate having conductivity. The material of the conductor may be any material having conductivity, and examples thereof include copper, aluminum, or an alloy of a metal having conductivity.

[0017] On one hand, as for the electric wire, it is an aggregate of linear strands having conductivity, that is, the strands are aggregated in a bundle shape, and the end portion on the side joined to the conductor is configured such that a plurality of strands are joined to each other, for example, by ultrasonic bonding. Further, the bundled strands are shaped to have the same shape as the end face of the conductor in a state where they are, for example, ultrasonically bonded. The tip face of such a bundled strand abuts against the end face of the conductor, and the bundled strand is electrically connected (butted connection) to the conductor. Then, in order to maintain the electrical connection state between the bundled strand and the conductor, as will be described later, the joint portion between the bundled strand and the conductor is fusion-bonded by welding. Note that the "butted connection" means a state where, as shown in FIG. 1, the tip face of the strand forming portion 14 of the electric wire 18 is pressed against the end face of the conductor 12, and the conductor 12 and the strand forming portion 14 are electrically connected.

[0018] Also, at one end of the electric wire, a covering portion (not shown) is stripped and the strands are exposed. Note that the shape of the electric wire may be flat or cylindrical, but at the tip portion, it is shaped such that the cross section is rectangular. That is, it is preferably shaped to have the same shape as the end portion of the conductor. However, different shapes may be used as long as sufficient bonding strength can be ensured between the end face of the conductor and the end portion of the electric wire joined to the end face. Examples of the material of the electric wire include copper, aluminum, or an alloy of a metal having conductivity, similar to the conductor.

[0019] [Process B] Process B is a process of performing uneven processing on one end face of the conductor. In FIGS. 2A and 2B, a form in which the uneven processing is performed by knurling is shown. FIG. 2A shows a side view of the conductor 12 after knurling, and FIG. 2B shows an end view of the conductor 12, that is, the surface on which the knurling is performed. As shown in FIGS. 2A and 2B, the end face of the conductor 12 has unevenness in a herringbone pattern formed by knurling. That is, the end face of the conductor 12 includes a plurality of recesses, and in Process C described later, the strands of the electric wire protruding to the outside enter the plurality of recesses.

[0020] The concavo-convex processing performed in Project B includes the above-mentioned knurling processing and the like. For example, it may be processed into a shape in which a large number of convex shapes with pointed tips such as a conical shape are arranged. Also, the knurling processing may be either cutting processing or rolling processing. As an example of knurling processing, there is a herringbone knurling processing with a recess depth of 0.2 to 2.0 mm. As will be described later, in order for the tip of the strand of the electric wire not to protrude outside and to sufficiently enter the recess, the depth of the recess by the concavo-convex processing is preferably 0.2 to 2.0 mm.

[0021] In FIGS. 2A and 2B, a form in which herringbone-patterned concavo-convexities are formed on one end surface of the conductor by knurling processing is shown, but knurling processing in which flat-patterned concavo-convexities are formed may also be used. However, in terms of sufficiently suppressing the protrusion of the strand to the outside, knurling processing in which herringbone-patterned concavo-convexities are formed is preferable.

[0022] The knurling processing of one end surface of the conductor can be performed by a conventional method using a knurling machine.

[0023] [Process C] Step C is a step of pressing one end of an electric wire against a surface where uneven processing has been performed on a conductor (hereinafter, the portion where uneven processing has been performed on the surface is referred to as the "uneven processed portion"). That is, one end of the electric wire is pressed against the end face of the conductor that has been uneven processed in Step B. More specifically, the aggregate of strands exposed at one end of the electric wire is pressed against the uneven processed portion of the end face of the conductor, and the strands protruding to the outside are pushed into the concave portion of the uneven processed portion. An example in which knurling is adopted as the uneven processing is shown in FIGS. 3 to 5 for the state. And the portion where knurling is performed is called the "knurled portion". First, as shown in FIG. 3, the knurled portion 22 of the end face of the conductor 12 is opposed to the end of the strand forming portion 14 of the electric wire 18. Next, as shown in FIG. 4, the end of the strand forming portion 14 of the electric wire 18 is brought into contact with the knurled portion 22 of the end face of the conductor 12. Further, as shown in FIG. 5, it is pressed so that the strands protruding to the outside from the end of the strand forming portion 14 are pushed into the concave portion formed in the knurled portion 22 of the end face of the conductor 12. Through the above steps, a temporary joint portion 24 is formed between the conductor 12 and the strand forming portion 14. And by temporarily joining in this way, it is possible to suppress the strands at the end of the strand forming portion 14 from protruding to the outside. On the other hand, after performing Step C, if the strands protrude to the outside, it is preferable to temporarily separate the electric wire pressed against the conductor from the conductor and repeat Step C until the strands no longer protrude to the outside.

[0024] [Step D] Step D is a step of welding the temporary joint between the electric wire and the conductor to join the electric wire and the conductor. That is, in Step D, the electric wire and the conductor temporarily joined in Step C are permanently joined. The joining of the electric wire and the conductor is performed by welding. Examples of welding include laser welding, resistance welding, spot welding, etc. Among them, laser welding, which is simple and can obtain a sufficient welding effect, is preferable. In the case of laser welding, for example, as shown in FIG. 6, a laser beam LB for welding is irradiated toward the temporary joint 24 between the conductor 12 and the electric wire 18 using a laser welding machine (not shown) disposed above the temporary joint 24. Here, since the depth that can be welded by laser welding is 3 mm or less, it is preferable that the irradiation of the laser beam LB is performed over the entire outer periphery of the temporary joint 24 between the electric wire and the conductor. By doing so, at the temporary joint 24, the joint 20 is formed and welded by the end face of the conductor 12 heated and melted by the laser beam LB and the end face of the strand forming portion 14.

[0025] The laser beam used for laser welding only needs to heat the irradiated part and be able to melt the conductor and the electric wire (strands) as described above. The type of laser beam (carbon dioxide laser, YAG laser, semiconductor laser, etc.) and the medium of the laser beam (gas, solid) can be appropriately selected as needed.

[0026] In the above manner, the end of the electric wire 18 and the end face of the conductor 12 are electrically connected, and the electric wire 10 with a conductor is completed.

[0027] As described above, since the strands of the electric wire are suppressed from protruding outside in Step C, even after laser welding is performed in Step D, the strands can be suppressed from protruding outside. Therefore, it is not necessary to reprocess the joint between the electric wire and the conductor, and the productivity can be improved. In addition, it is possible to prevent tearing of the insulating protective tape, tube, etc. applied to the electric wire caused by the strands protruding outside. As a result, it is possible to reduce measures such as forming the protective tape, tube, etc. thicker or cutting the protruding strands.

[0028] Although the present embodiment has been described above, the present embodiment is not limited to these, and various modifications are possible within the scope of the gist of the present embodiment.

Explanation of Reference Numerals

[0029] 10 Electric wire with conductor (conductor connection structure) 12 Conductor 14 Strand forming part 16 Strand 18 Electric wire 20 Joint part 22 Knurling part LB Laser beam

Claims

1. A step of preparing a conductor formed in a plate shape and an electric wire in which a plurality of strands are bundled together; A step of performing uneven processing on one end surface of the conductor; A step of pressing one end portion of the electric wire against the surface of the conductor subjected to the uneven processing to temporarily join the electric wire and the conductor; and A step of welding the temporary joint portion between the electric wire and the conductor to join the electric wire and the conductor. A manufacturing method of a conductor connection structure, including the above steps.

2. The manufacturing method of the conductor connection structure according to Claim 1, wherein the depth of the recess on one end surface of the conductor formed by the uneven processing is 0.2 to 2.0 mm.

3. The manufacturing method of the conductor connection structure according to Claim 1 or 2, wherein the uneven processing is performed by knurling.

4. The manufacturing method of the conductor connection structure according to Claim 3, wherein a diamond pattern is formed on one end surface of the conductor by the knurling.

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