Conductor connection structure and method for manufacturing the same

Abstract

To provide a conductor connection structure that performs pre-heating from the start of laser irradiation to efficiently increase the temperature of an abutting joint surface, thereby improving the productivity of laser welding, and a method for manufacturing the same.SOLUTION: A conductor connection structure 1 comprises an electric wire 10 having a plurality of element wires 22 and a plate-like conductor 30, and the electric wire 10 and the conductor 30 are connected to each other in the conductor connection structure 1. With the plurality of element wires 22 formed in a plate state, end faces 221 of the plurality of element wires and an end face 321 of the conductor are abutted and connected to each other. The end face 321 of the conductor is provided with at least one conductor extension part 31 projecting toward the direction of the electric wire 10 from an end in a width direction of the conductor 30. Laser traces L5, which are caused by irradiation with a laser beam L, are formed between side faces 222 of the plurality of element wires and a side face 311 of the conductor extension part, and between end faces 221 of the plurality of element wires and the end face 321 of the conductor, respectively.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to a conductor connection structure and a method for manufacturing the same. [Background technology]

[0002] A wide variety of electronic devices are installed in automobiles, and wire harnesses are arranged to transmit power, control signals, etc. to the electronic devices. The wire harnesses include multiple electric wires and connectors, and are connected to the electronic devices or other wire harnesses by fitting the connectors to the connectors of the electronic devices or the connectors of other wire harnesses.

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

[0004] Patent Document 1 discloses an electric wire with terminal, which includes an electric wire in which a conductor made of a material primarily containing a first metal is coated with an insulating material, and a terminal made of a material primarily containing a second metal different from the first metal and connected to the conductor exposed at one end of the electric wire. The electric wire with terminal further includes an alloy layer containing the first metal and the second metal formed along the entire outer periphery of the contact portion between the conductor and the terminal, spanning the conductor and the terminal. Specifically, the conductor, which includes multiple strands, and the terminal are butted together, and the contact portion between the conductor and the terminal is joined using a laser welder. The resulting joint between the conductor and the terminal forms an alloy layer, establishing electrical continuity and a strong bond between them. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2018-190617 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the multiple core wires exposed by the stripping process are heated and pressurized to form the electric wire conductor into a desired shape (plate-like, cylindrical, etc.) to fit the mating terminal, and then the electric wire conductor is butt-joined to the terminal by laser welding. When the electric wire conductor formed before welding has high strength and density, it is difficult to raise the temperature required for laser welding at the laser irradiation start position, resulting in a problem of insufficient welding of the butt-joining surfaces. One possible solution to this problem is to use a high-power laser irradiation device or a combined laser, but this leads to increased manufacturing costs. For these reasons, improving productivity when butt-joining by laser welding has been an issue.

[0007] The present invention has been made in view of the problems inherent in the prior art, and an object of the present invention is to provide a conductor connection structure and a manufacturing method thereof that improves the productivity of laser welding by efficiently raising the temperature of the butt joint surfaces through preheating from the start of laser irradiation. [Means for solving the problem]

[0008] A conductor connection structure according to one aspect of the present invention comprises an electric wire having a plurality of strands and a plate-shaped conductor, and is a conductor connection structure in which the electric wire and the conductor are connected, wherein the plurality of strands are formed into a plate shape and the end faces of the plurality of strands and the end face of the conductor are butted against each other to be connected, and the end face of the conductor is provided with at least one conductor extension portion that protrudes from the end of the conductor in the width direction toward the electric wire, and laser marks caused by irradiation with laser light are formed between the side faces of the plurality of strands and the side faces of the conductor extension portion, and between the end faces of the plurality of strands and the end face of the conductor.

[0009] A manufacturing method of a conductor connection structure according to an embodiment of the present invention is a manufacturing method of a conductor connection structure comprising an electric wire having a plurality of wires and a plate-shaped conductor, and connecting the electric wire and the conductor, and includes the steps of: abutting the end faces of the plurality of plate-shaped wires against an end face of the conductor, which has at least one conductor extension portion protruding from the widthwise end of the conductor toward the electric wire; and forming laser marks by irradiating laser light between the side faces of the plurality of wires and the side faces of the conductor extension portion, and between the end faces of the plurality of wires and the end face of the conductor. [Effects of the Invention]

[0010] According to the present invention, a conductor connection structure and a manufacturing method thereof can be provided in which preheating is performed from the start of laser irradiation, thereby efficiently raising the temperature of the butt joint surface and improving the productivity of laser welding. [Brief explanation of the drawings]

[0011] [Figure 1A] 1 is a side view showing an example of a conductor connection structure according to an embodiment of the present invention. [Figure 1B] 1 is a plan view showing an example of a conductor connection structure according to an embodiment of the present invention. [Figure 1C] FIG. 1C is an enlarged view of the joint portion of FIG. 1B. [Figure 2] FIG. 2 is a plan view showing a state before laser welding in the conductor connection structure according to the present embodiment. [Figure 3] 3 is a plan view illustrating an example of a conductor in the conductor connection structure according to the embodiment. FIG. [Figure 4] 3 is a plan view illustrating an example of a conductor in the conductor connection structure according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] The conductor connection structure and the manufacturing method thereof according to the present embodiment will be described in detail below with reference to the drawings. Note that the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0013] [Conductor connection structure] 1A, an electric wire with conductor 1 to which the conductor connection structure according to this embodiment is applied includes an electric wire 10 and a conductor 30 connected to the tip of the electric wire 10. Specifically, the electric wire with conductor (conductor connection structure) 1 includes an electric wire 10 having a plurality of element wires 22 and a plate-shaped conductor 30, and the electric wire 10 and the conductor 30 are connected to each other.

[0014] The electric wire 10 is a coated electric wire having a plurality of wires 22 and an insulating sheath 21 that covers the plurality of wires 22. The plurality of wires 22 may be made of a conductive metal material such as copper, a copper alloy, aluminum, or an aluminum alloy. The insulating sheath 21 is made of a resin material that is flexible and electrically insulating. The structure of the plurality of wires 22 (electric wire conductor) is not limited to a twisted wire in which a plurality of core wires are twisted together, and may be other forms (single-core wire, braided wire, etc.). At one end of the electric wire 10, the insulating sheath 21 is removed to expose a portion of the plurality of wires 22.

[0015] The exposed wires 22 are formed into a substantially rectangular shape in plan view, with end surfaces 221 of the wires formed on the conductor 30 side for butt-joining. The wires 22 and end surfaces 221 are formed into a plate shape before welding. The wires 22 may be formed by ultrasonic welding, resistance welding, heat welding, or other methods. The shape of the wires 22 may be any shape that fits the mating conductor 30, and may be flat or cylindrical.

[0016] The conductor 30 is formed as a flat conductor body 32, and has an end surface 321 of the conductor for butt-joining on the side of the electric wire 10. The end surface 321 of the conductor is provided with at least one conductor extension 31 that protrudes from an end of the conductor 30 in the width direction toward the electric wire 10. The conductor 30 may be a substantially rectangular parallelepiped plate-like member, a bus bar, or a laminated thin plate.

[0017] The conductor 30 is made of a conductive metal, and at least the end portion and the end surface 321 of the conductor are plate-shaped components. The conductor 30 is formed by processing a plate made of a conductive metal material such as copper, a copper alloy, aluminum, or an aluminum alloy. The conductor 30 may be made of a single-layer metal plate, or may be made of a laminated plate made by stacking multiple thin metal plates. The surface of the conductor 30 may also be subjected to a surface treatment such as plating.

[0018] In this embodiment, the thickness of the conductor 30 is approximately the same as the thickness of the plurality of wires 22. The thickness of the conductor 30 is not particularly limited, but can be, for example, 3 mm to 6 mm.

[0019] The conductor 30 (conductor body 32) may have a hole penetrating the front and back surfaces of the conductor body 32. A fastening member such as a bolt or a screw may be inserted into this hole, and the conductor 30 may be fastened to a connected portion of various devices, etc., for fixed and electrically connected. Furthermore, the conductor 30 may be formed with a leaf spring or a protrusion to prevent it from coming loose when inserted into a connector, etc.

[0020] 1B, in the conductor-equipped electric wire 1, a plurality of wires 22 are formed into a plate shape, and end faces 221 of the plurality of wires are connected to an end face 321 of the conductor by butting them against each other. At least one conductor extension 31 is provided on the end face 321 of the conductor, protruding from an end of the conductor 30 in the width direction toward the electric wire 10.

[0021] 2, the gap a formed between the side surface 311 of the conductor extension 31 and the side surface 222 of the plurality of strands 22 is preferably 0 mm or more and 0.8 mm or less, and more preferably 0 mm. A gap a of 0 mm indicates that no gap is formed between the conductor extension 31 and the plurality of strands 22, and the conductor extension 31 and the plurality of strands 22 are in contact with each other. By setting the gap a within the above range, the plurality of strands 22 are preheated when the laser light is scanned from the scanning start position L3 to the scanning intermediate position L4, as described below, and the temperature of the butt joint surfaces can be efficiently increased.

[0022] 3, the width b of the conductor extension 31 is preferably 2 mm or more and 5 mm or less. Furthermore, the length c of the conductor extension 31 is preferably 0.75 mm or more and 2 mm or less. By setting the width b and length c of the conductor extension 31 within the above ranges, as will be described later, the plurality of strands 22 are preheated when the laser light is scanned from the scanning start position L3 to the scanning intermediate position L4, and the temperature of the butt joint surfaces can be efficiently increased.

[0023] The conductor extensions 31 may protrude from both widthwise ends of the conductor 30 toward the electric wire 10 as shown in FIG. 4, and in this case, the shape of the conductor extensions 31 may be asymmetric.

[0024] In this embodiment, the end faces 221 of the multiple wires and the end face 321 of the conductor are butted against each other and connected. Specifically, the side faces 222 of the multiple wires and the side faces 311 of the conductor extension, and the end faces 221 of the multiple wires and the end face 321 of the conductor are welded and electrically connected by irradiation with laser light. As shown by the thick lines in FIGS. 1B and 1C , L-shaped laser marks L5 are formed between the side faces 222 of the multiple wires and the side faces 311 of the conductor extension, and between the end faces 221 of the multiple wires and the end face 321 of the conductor, due to the irradiation of laser light L.

[0025] In conventional methods of welding by irradiating a laser beam, if the strength and density of the shaped electric wire conductor before welding are high, it is difficult to raise the temperature at the laser irradiation start position to the level required for laser welding, and the butt joint surfaces may not be sufficiently welded. In the conductor connection structure of this embodiment, laser scanning is initiated from the portion between the side surface 222 of the plurality of wires and the side surface 311 of the conductor extension portion (scanning start position L3, described below), thereby preheating the plurality of wires 22 and then welding the butt joint surfaces. This preheating improves heat absorption efficiency, allowing for an efficient temperature increase at the butt joint surfaces. Furthermore, welding can be easily performed across the entire butt joint surfaces using a commonly used infrared (IR) laser, without requiring a high-power device or a composite laser. Therefore, the conductor connection structure of this embodiment can reduce manufacturing costs and improve productivity by easing welding conditions.

[0026] As described above, the conductor connection structure of this embodiment is a conductor connection structure 1 that includes an electric wire 10 having a plurality of element wires 22 and a plate-shaped conductor 30, and that connects the electric wire 10 and the conductor 30. Then, with the plurality of element wires 22 formed into a plate shape, end faces 221 of the plurality of element wires and an end face 321 of the conductor are butted against each other and connected. At least one conductor extension portion 31 that protrudes from an end of the conductor 30 in the width direction toward the electric wire 10 is provided on the end face 321 of the conductor. Furthermore, laser marks L5 caused by irradiation with laser light L are formed between the side faces 222 of the plurality of element wires and the side faces 311 of the conductor extension portion, and between the end faces 221 of the plurality of element wires and the end face 321 of the conductor.

[0027] In the above-described conductor connection structure, laser scanning is initiated from the portion between the side surface 222 of the plurality of wires and the side surface 311 of the conductor extension portion, thereby preheating the plurality of wires 22 and then welding the butt joint surfaces. This allows the temperature of the butt joint surfaces to be efficiently increased, and welding can be easily performed over the entire butt joint surfaces. From the above, the conductor connection structure of this embodiment can provide a conductor connection structure that efficiently increases the temperature of the butt joint surfaces by preheating from the start of laser irradiation, thereby improving the productivity of laser welding.

[0028] [Method of manufacturing conductor connection structure] Next, a description will be given of a method for manufacturing the conductor-equipped electric wire (conductor connection structure) 1 according to this embodiment. The method for manufacturing the conductor-equipped electric wire 1 is a method for manufacturing a conductor connection structure 1 that includes an electric wire 10 having a plurality of element wires 22 and a plate-shaped conductor 30, and that connects the electric wire 10 and the conductor 30.

[0029] The manufacturing method of the conductor-equipped electric wire 1 includes a step of butting end faces 221 of a plurality of wires formed in a plate shape against an end face 321 of the conductor having at least one conductor extension portion 31 that protrudes from an end portion in the width direction of the conductor 30 toward the electric wire 10. This step is a preparation step before welding, by irradiation of laser light, between the side faces 222 of the plurality of wires and the side faces 311 of the conductor extension portion, and between the end faces 221 of the plurality of wires and the end face 321 of the conductor.

[0030] The manufacturing method of the conductor-equipped electric wire 1 includes a step of forming L-shaped laser marks L5 by irradiating laser light L between the side surfaces 222 of the plurality of wires and the side surfaces 311 of the conductor extension portion, and between the end surfaces 221 of the plurality of wires and the end surface 321 of the conductor. This step is a step of welding between the side surfaces 222 of the plurality of wires and the side surfaces 311 of the conductor extension portion, and between the end surfaces 221 of the plurality of wires and the end surface 321 of the conductor by irradiating laser light.

[0031] The laser light L may be scanned in the longitudinal direction L1 of the electric wire 10 and then in the width direction L2 of the electric wire 10. That is, in Figures 1B and 1C, the laser light L may be scanned in the direction of the arrow pointing from right to left and then in the direction of the arrow pointing from top to bottom. Specifically, the laser light L may be scanned in the longitudinal direction L1 of the electric wire 10 and then in the width direction L2 of the electric wire 10, with the portion between the side surface 222 of the multiple wires and the side surface 311 of the conductor extension portion set as the scanning start position L3 and the end portions of the end surfaces 221 of the multiple wires set as the scanning intermediate position L4.

[0032] As shown in Fig. 1C, the plurality of wires 22 have side surfaces 222 formed on the conductor extension 31 side. Meanwhile, the conductor extension 31 has side surfaces 311 formed on the conductor extension side on the plurality of wires 22 side. Scanning start position L3 is the portion of the plurality of wires 22 that is welded between the side surfaces 222 of the plurality of wires and the side surfaces 311 of the conductor extension. From the viewpoint of sufficiently preheating the plurality of wires 22, it is preferable to set scanning start position L3 at the tip of the side surfaces 311 of the conductor extension as shown in Fig. 1C.

[0033] On the other hand, the scanning intermediate position L4 is a corner where the end faces 221 and the side faces 222 (the upper side faces in FIG. 1C ) of the plurality of wires 22 intersect, and is a portion to be welded to the end faces 321 of the conductors. From the scanning intermediate position L4, the laser light L is scanned along the width direction L2 of the electric wire 10, thereby welding the butt joint surfaces.

[0034] In the manufacturing method of the conductor connection structure of this embodiment, laser irradiation is started from the conductor extension portion 31 (scanning start position L3), and the plurality of strands 22 are preheated as the laser light scans from the scanning start position L3 to the scanning intermediate position L4. After preheating the plurality of strands 22, the butt joint surfaces are welded from the scanning intermediate position L4. Therefore, preheating improves the heat absorption efficiency, and the temperature of the butt joint surfaces can be efficiently increased. Furthermore, welding can be easily performed over the entire butt surfaces even with a commonly used infrared (IR) laser. Therefore, the manufacturing method of the conductor connection structure of this embodiment can reduce manufacturing costs and improve productivity by relaxing welding conditions.

[0035] 4, the conductor extensions 31 may protrude from both ends of the conductor 30 in the width direction toward the electric wire 10. In this case, the scanning start position L3 and the scanning intermediate position L4 may be set in either one of the two conductor extensions 31. The laser light L may be scanned in the longitudinal direction L1 of the electric wire 10 and then in the width direction L2 of the electric wire 10 in accordance with the scanning start position L3 and the scanning intermediate position L4.

[0036] As described above, the manufacturing method of the conductor connection structure according to this embodiment is a manufacturing method of a conductor connection structure 1 including an electric wire 10 having a plurality of wires 22 and a plate-shaped conductor 30, and connecting the electric wire 10 and the conductor 30. The manufacturing method includes a step of butting the end faces 221 of the plurality of wires formed in a plate shape against an end face 321 of a conductor having at least one conductor extension 31 protruding from an end of the conductor 30 in the width direction toward the electric wire 10. The manufacturing method also includes a step of forming laser marks L5 by irradiating laser light L between the side faces 222 of the plurality of wires and the side faces 311 of the conductor extension, and between the end faces 221 of the plurality of wires and the end face 321 of the conductor. Therefore, the manufacturing method of the conductor connection structure according to this embodiment can provide a manufacturing method of a conductor connection structure that efficiently increases the temperature of the butt joint surfaces by preheating from the start of laser irradiation, thereby improving the productivity of laser welding.

[0037] Although the present embodiment has been described above, the present embodiment is not limited to this, and various modifications are possible within the scope of the gist of the present embodiment. [Explanation of symbols]

[0038] 1 Conductor-attached wire (conductor connection structure) 10 Electric wire 22 Multiple wires 30 Conductors 31 Conductor extension 221 End faces of multiple wires 222 Side of multiple wires 311 Side of conductor extension 321 Conductor end face L laser light L1 Longitudinal direction of the wire L2 Wire width direction L3 Scan start position L4 Scanning midpoint L5 laser scar

Claims

1. A conductor connection structure comprising an electric wire having a plurality of wires and a plate-shaped conductor, the electric wire and the conductor being connected together, The plurality of wires are formed into a plate shape, and end faces of the plurality of wires and an end face of the conductor are butted against each other and connected to each other, At least one conductor extension portion is provided on an end surface of the conductor, protruding from an end portion in a width direction of the conductor toward the electric wire, A conductor connection structure in which laser marks are formed between the side surfaces of the plurality of wires and the side surfaces of the conductor extension portion, and between the end surfaces of the plurality of wires and the end surfaces of the conductor, due to irradiation with laser light.

2. A method for manufacturing a conductor connection structure comprising an electric wire having a plurality of wires and a plate-shaped conductor, the electric wire and the conductor being connected, a step of abutting end surfaces of the plurality of wires formed in a plate shape against an end surface of the conductor, the end surface having at least one conductor extension portion protruding from an end portion in a width direction of the conductor toward the electric wire; forming laser marks by irradiating laser light between the side surfaces of the plurality of wires and the side surfaces of the conductor extension portion, and between the end surfaces of the plurality of wires and the end surface of the conductor; A method for manufacturing a conductor connection structure comprising:

3. 3. The method for manufacturing a conductor connection structure according to claim 2, wherein the laser light is scanned along the longitudinal direction of the electric wire and then along the width direction of the electric wire, with the area between the side surfaces of the plurality of wires and the side surfaces of the conductor extension portion as the scanning start position and the ends of the end surfaces of the plurality of wires as the scanning intermediate position.

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