Method for manufacturing aluminum wires, method for manufacturing aluminum wires with crimp terminals, and apparatus for manufacturing aluminum wires.

Abstract

To provide a manufacturing method capable of manufacturing an aluminum wire of high connection reliability by welding and electrically integrating all strands constituting a terminal part through one time of arc-welding even in the case of a thick aluminum wire when welding the terminal part of a conductor consisting of a plurality of strands of the aluminum wire.SOLUTION: A manufacturing method of an aluminum wire includes: an exposure step of forming a conductor exposed part by peeling an insulation coating layer and exposing a conductor in a terminal part of the aluminum wire; and an integration step of forming an electrically integrated strand integration part in a distal end portion of the conductor exposed part by forming a plasma arc between an end face of the conductor exposed part and a distal end of an electrode of an arc discharge device disposed oppositely to the end face and solidifying the conductor exposed part after fusing terminal parts of all the strands constituting the conductor exposed part by the plasma arc with which the end face is irradiated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an aluminum electric wire, a method for manufacturing an aluminum electric wire with a crimp terminal, and a manufacturing apparatus for an aluminum electric wire.

Background Art

[0002] Conventionally, when connecting the end of an electric wire having a conductor composed of a plurality of strands to the end of another electric wire or the like, an aluminum electric wire with a crimp terminal is used. Generally, in the case of an aluminum electric wire, since each strand constituting the conductor has a property of easily forming an oxide film on its surface, the formed oxide film tends to inhibit the conduction between the strands in the conductor. For this reason, as a means for ensuring conduction between strands by peeling off the oxide film of the strands, the end of a conductor composed of a plurality of aluminum strands is crimped and connected with a crimp terminal. However, it is impossible to completely peel off the oxide films of all the strands constituting the conductor. In particular, in the case of a thick aluminum electric wire with a conductor size exceeding 3 sq(mm 2 ), sufficient conduction may not be obtained.

[0003] For example, in Patent Document 1, the entire outer periphery of the conductor portion is coated with solder to form a solder coating portion, the conductor portion coated with the solder is placed on the conductor crimping portion of the crimp terminal, and a strong crimping portion is formed by crimping with a strength such that the solder coating portion of the conductor portion cracks, and a weak crimping portion is formed by crimping with a strength such that the solder coating portion does not crack due to the crimping force on the tip side of the strong crimping portion. The conductor crimping portion is clamped, and an aluminum electric wire with a crimp terminal formed by connecting the conductor portion and the conductor crimping portion is described.

[0004] In the technique of Patent Document 1, by previously welding the strands in the conductor with solder and attaching a crimp terminal, the connection reliability when connecting an aluminum electric wire to another electric wire or the like can be improved. However, solder for aluminum is very expensive, and welding with solder takes a very long time, so there are problems in practical use.

[0005] Arc welding and laser welding can be used to weld strands together within a conductor, for example, 3 sq (mm 2 When welding the end faces of conductors that make up thick aluminum wires exceeding a certain thickness using methods such as arc welding, the welding area (irradiation area) is limited to a certain range. Therefore, it is difficult to melt and solidify the entire end face of the conductor in a single welding pass, resulting in the problem that it is not possible to obtain aluminum wires with high connection reliability. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-26905 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a method for manufacturing aluminum wires and an apparatus for manufacturing aluminum wires, and a method for manufacturing aluminum wires with crimp terminals using said aluminum wires, which enable the welding of the terminal portion of a conductor consisting of multiple strands of aluminum wire using arc welding, so that even in the case of thick aluminum wires, all strands constituting the terminal portion can be melted and solidified in a single arc welding, thereby electrically integrating them and enabling the production of aluminum wires with high connection reliability in a short time. [Means for solving the problem]

[0008] To achieve the above objective, the gist of the present invention is as follows. [1] A method for manufacturing an aluminum wire having a conductor composed of a plurality of strands made of an aluminum-based material and an insulating coating layer covering the conductor, wherein the terminal portion of the aluminum wire has an exposed conductor portion integrated in an exposed state, The process involves removing the insulating coating layer at the terminal end of the aluminum wire to expose the conductor and form an exposed conductor portion, An integration process is performed by forming a plasma arc between the end face of the exposed conductor portion and the tip of an electrode of an arc discharge device positioned opposite the end face, thereby melting and solidifying the terminal portions of all the strands constituting the exposed conductor portion with the plasma arc irradiated onto its end face, and thereby forming an electrically integrated strand portion at the tip of the exposed conductor portion. Includes, The aforementioned integration process is, When x is the distance between the end face of the exposed conductor and the tip of the electrode of the arc discharge device, and d is the diameter of the end face of the exposed conductor that is irradiated with the plasma arc, A method for manufacturing an aluminum electric wire, characterized in that the arc length corresponding to the distance x is set such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor portion. [2] The method for manufacturing an aluminum electric wire according to [1] above, characterized in that the integration step is performed by setting the arc current value to a value corresponding to the distance x such that the energy density of the plasma arc is constant according to the diameter d of the end face of the exposed conductor portion. [3] A method for manufacturing an aluminum wire with a crimp terminal, A method for manufacturing an aluminum wire with a crimp terminal, characterized by including a crimping step of crimping and attaching a crimp terminal to the exposed conductor portion including the strand-integrated portion of the aluminum wire described in [1] or [2] above. [4] An aluminum wire manufacturing apparatus having an exposed conductor portion integrated in an exposed state at the terminal end of an aluminum wire having a conductor composed of a plurality of strands made of an aluminum-based material and an insulating coating layer covering the conductor, Shield case and Arc discharge device and Equipped with, The aforementioned arc discharge device Electrodes and, An earth chuck is installed as a counter electrode at a position opposite to the aforementioned electrode, and grips the exposed conductor portion such that the tip portion, which is the part that melts and solidifies, is exposed to the electrode side. A power supply unit that applies a voltage between the electrode and the earth chuck, A drive unit that adjusts the distance between the electrode and the earth chuck, An inert gas supply unit that supplies inert gas, At least the power supply unit and the control unit that controls the drive unit Equipped with, When x is the distance between the end face of the exposed conductor and the tip of the electrode of the arc discharge device, and d is the diameter of the end face of the exposed conductor that is irradiated with the plasma arc, An aluminum wire manufacturing apparatus characterized in that the drive unit is controlled by the control unit, thereby setting the arc length corresponding to the distance x such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor portion. [5] The aluminum wire manufacturing apparatus according to [4] above, characterized in that the drive unit and the power supply unit are controlled by the control unit so that the energy density of the plasma arc is set to an arc current value corresponding to the distance x such that the energy density of the plasma arc is constant according to the diameter d of the end face of the exposed conductor. [Effects of the Invention]

[0009] The present invention aims to provide a method for manufacturing aluminum wires and an apparatus for manufacturing aluminum wires, as well as a method for manufacturing aluminum wires with crimp terminals using said aluminum wires. This method enables the welding of the terminal portion of a conductor consisting of multiple strands of aluminum wire using arc welding, and allows for the electrical integration of all strands constituting the terminal portion in a single arc welding, even in the case of thick aluminum wires, thereby enabling the production of aluminum wires with high connection reliability in a short time and with ease. [Brief explanation of the drawing]

[0010] [Figure 1] This is a diagram illustrating the manufacturing method of aluminum electric wire according to the present invention. [Figure 2] This is a diagram illustrating a conventional method for manufacturing aluminum electric wires. [Figure 3] It is a schematic cross-sectional view of the terminal part of an aluminum electric wire used in the method for manufacturing an aluminum electric wire of the present invention, where (A) shows the state before stripping the insulating coating layer, and (B) shows the state after stripping the insulating coating layer to expose the conductor. [Figure 4] It is a schematic diagram showing the manufacturing apparatus of the aluminum electric wire of the present invention. [Figure 5] It is a schematic cross-sectional view showing a part of an aluminum electric wire in which a stranded wire integrated part is formed at the terminal part by the method for manufacturing an aluminum electric wire of the present invention. [Figure 6] It is a schematic diagram showing an example when the integration process constituting the method for manufacturing an aluminum electric wire of the present invention is performed. [Figure 7] It is a perspective view showing an example of the shape of a crimp terminal before crimping. [Figure 8] It is a schematic cross-sectional view of an aluminum electric wire with a crimp terminal manufactured by the aluminum electric wire with a crimp terminal of the present invention.

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] [Manufacturing Apparatus for Aluminum Electric Wire] The present invention relates to an aluminum wire manufacturing apparatus having an exposed conductor portion integrated in an exposed state at the terminal end of an aluminum wire having a conductor composed of a plurality of strands made of an aluminum-based material and an insulating coating layer covering the conductor, comprising a shield case and an arc discharge device, wherein the arc discharge device comprises an electrode, an earth chuck installed as a counter electrode at a position opposite to the electrode and gripping the conductor exposed portion with the tip side portion, which is the melted and solidified part, exposed to the electrode side, a power supply unit that applies a voltage between the electrode and the earth chuck, a drive unit that adjusts the distance between the electrode and the earth chuck, an inert gas supply unit that supplies an inert gas, and a control unit that controls at least the power supply unit and the drive unit, wherein when the distance between the end face of the conductor exposed portion and the tip of the electrode of the arc discharge device is x, and the diameter of the end face of the conductor exposed portion irradiated with the plasma arc is d, the control unit controls the drive unit to set the arc length corresponding to the distance x such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the conductor exposed portion.

[0013] Figure 2 is an explanatory diagram illustrating a conventional method for manufacturing aluminum electric wires. An aluminum electric wire has a conductor composed of multiple strands made of an aluminum-based material, and an insulating coating layer covering the conductor. As shown in Figure 2, an aluminum electric wire is used in which the insulating coating layer 33 of the terminal portion 30 is stripped to form an exposed conductor portion 31. The inventors investigated a case in which an exposed conductor portion is formed in an exposed state on the terminal portion 30 of such an aluminum electric wire using arc welding, and found that, in particular, 3 sq (mm 2When the material is thicker than ), as shown in Figure 2, the plasma arc P is formed between the electrode 11 of the arc discharge device (see Figure 4) and the end face 31a of the exposed conductor. However, when using a normal arc welding method, the irradiation area (irradiation spot) of the plasma arc P on the end face 31a of the exposed conductor becomes narrow, making it difficult to irradiate the entire end face 31a of the exposed conductor with the plasma arc P. Furthermore, in such cases, with a single arc welding, the welded portion w is formed only in the central region of the end face 31a, and an unwelded portion u remains in the outer peripheral region of the end face. As a result, it is not possible to weld all the individual wires 32 constituting the exposed conductor 31 together to form an integrated exposed conductor 31, and it has been found that stable electrical conductivity cannot be obtained for all the individual wires constituting the conductor.

[0014] Figure 1 is a diagram illustrating the manufacturing method of aluminum electric wire according to the present invention. As shown in Figure 1, the manufacturing apparatus for aluminum electric wire according to the present invention sets the distance x (arc length) between the end face 31a of the exposed conductor portion and the tip of the electrode 11 so that the irradiation spot diameter of the plasma arc P irradiated substantially radially from the electrode 11 is substantially the same as the diameter d of the end face 31a of the exposed conductor portion. As a result, all the strands 32 constituting the end face 31a of the exposed conductor portion can be easily integrated in a short time with a single arc welding. Furthermore, since all the strands 32 constituting the end face 31a of the exposed conductor portion are welded and a strand-integrated portion is formed, these strands 32 are electrically connected to each other, so it is possible to manufacture aluminum electric wires with high connection reliability when connecting to, for example, crimp terminals.

[0015] (Aluminum wire) Before describing in detail the aluminum wire manufacturing apparatus of the present invention, we will first describe the aluminum wire to which the manufacturing apparatus of the present invention is used. Figure 3 is a schematic cross-sectional view showing an example of an aluminum wire. As shown in Figure 3(A), the aluminum wire 1 comprises a conductor 3 composed of a plurality of strands 2 and an insulating coating layer 4.

[0016] The shape of the cross-section perpendicular to the extension direction of the conductor 3 (hereinafter also referred to as the cross-section of the conductor 3) may be circular or rectangular. The conductor 3 may also be compressed. The conductor 3 may be a bundle of multiple strands 2 as shown in Figure 3(A), or a stranded wire made by twisting multiple strands 2 together.

[0017] The strands 2 constituting the conductor 3 are made of an aluminum-based material. That is, the conductor 3 is made of an aluminum-based material. From the viewpoint of reducing the electrical resistance of the conductor 3, it is preferable that the composition of the conductor 3 contains 99.0% by mass or more of Al. That is, it is preferable that the conductor 3 is made of pure aluminum.

[0018] The aluminum wire manufacturing apparatus and the manufacturing method described later in the present invention can be applied to any size of conductor size (nominal cross-sectional area) of the aluminum wire 1, and the conductor size (mm 2 ) For example, 3.0 mm 2 20.0mm 2 The following applies: From the viewpoint of obtaining the effects of the present invention more significantly, the lower limit of the conductor size is preferably 3 mm. 2 It is larger than that. On the other hand, from the viewpoint of making the conductor size easily applicable to arc welding technology, 16.0 mm is preferable. 2 The following applies. Note that the diameter and area of ​​the end face of the exposed conductor at the end of an aluminum wire are usually the same as the diameter and cross-sectional area (nominal cross-sectional area) of the conductor.

[0019] The insulating coating layer 4 that constitutes the aluminum wire 1 has electrical insulating properties and covers the outer circumference of the conductor 3. The insulating coating layer 4 is made of, for example, an electrically insulating resin. The shape of the insulating coating layer 4 is cylindrical.

[0020] In the aluminum wire manufacturing apparatus of the present invention, as shown in Figure 3(B), at the terminal portion of the aluminum wire 1, the insulating coating layer 4 covering the outer circumference of the conductor 3 is stripped from the aluminum wire 1 (so-called stripping), thereby forming an exposed conductor portion 31 at the terminal portion 30.

[0021] (Overview of aluminum wire manufacturing equipment) The aluminum wire manufacturing apparatus A of the present invention comprises a shield case 20 and an arc discharge device 10, as shown in Figure 4. The target of processing by the manufacturing apparatus A is the exposed conductor portion 31 formed at the terminal portion 30 of the aluminum wire 1 described above.

[0022] (Arc discharge device) As shown in Figure 4, the arc discharge device 10 of the aluminum wire manufacturing apparatus A of the present invention comprises an electrode 11, an earth chuck 12 installed as a counter electrode opposite the electrode 11 and gripping the exposed conductor portion 31 with the tip portion, which is the part to be melted and solidified, exposed to the electrode 11, a power supply unit 13 that applies a voltage between the electrode 11 and the earth chuck 12, a drive unit 14 that adjusts the distance between the electrode 11 and the earth chuck 12, an inert gas supply unit 15 that supplies an inert gas, and a control unit 16 that controls at least the power supply unit 13 and the drive unit 14.

[0023] Electrode 11 is usually a non-consumable electrode. The material of electrode 11 is not particularly limited, but tungsten is often used. In the aluminum wire manufacturing apparatus A of the present invention, electrode 11 becomes the anode when arc welding is performed.

[0024] The earth chuck 12 is positioned opposite the electrode 11 as the counter electrode. The earth chuck 12 grips the exposed conductor portion 31 of the terminal portion 30 of the aluminum wire to be welded, with the tip portion, which is the part to be melted and solidified, exposed to the electrode side. The earth chuck 12 becomes the cathode when arc welding is performed. The material of the earth chuck 12 can be any conductive material and is not particularly limited, but copper is an example.

[0025] The power supply unit 13 applies a voltage between the electrode 11 and the earth chuck 12 (between the electrodes). The application of voltage between the electrodes generates arc plasma between the electrode 11 and the end face 31a of the terminal portion 30 of the aluminum wire held by the earth chuck 12. The arc plasma generates high heat, causing arc welding to occur on the end face 31a of the exposed conductor portion of the aluminum wire terminal portion 30, forming a wire-integrated portion at the tip of the exposed conductor portion 31. In this invention, since the arc length may be set longer than in conventional devices, it is preferable to use a power supply unit 13 capable of applying high voltage and high current.

[0026] In the aluminum wire manufacturing apparatus of the present invention, the electrode 11 is connected to the power supply unit in reverse polarity, with the electrode 11 on the anode side and the earth chuck 12 on the cathode side, as described above. This is the opposite of the conventional arc welding method, where the electrode 11 is connected to the power supply unit in reverse polarity, with the electrode 11 on the cathode side and the earth chuck 12 that grips the aluminum wire on the anode side. Since the oxide film on the surface of the aluminum wire has a melting point of 2000°C or higher, when arc welding is performed with positive polarity, the inside of the wire, which has a lower melting point, melts first, making it difficult to fuse the wires together. Therefore, in the present invention, by performing arc welding with reverse polarity, electrons in the arc discharge are released from the oxide generated on the surface of the aluminum wire and reduced, resulting in a so-called cleaning action. As a result, the wires at the end of the aluminum wire melt and solidify, making it easier to form a unified wire section.

[0027] The drive unit 14 adjusts the distance between the electrode 11 and the earth chuck 12. This distance adjustment is usually performed by moving the electrode 11 relative to the end face 31a of the exposed conductor portion, as shown in Figure 6, but the earth chuck 12, which grips the end face 31a of the exposed conductor portion, may also be moved relative to the electrode 11. A motor cylinder or the like is used as the drive unit.

[0028] The inert gas supply unit 15 supplies inert gas between the electrode 11 and the end face 31a of the exposed conductor portion of the aluminum wire, i.e., to the area where the arc plasma is generated. The inert gas is used as a shielding gas to protect the arc discharge from the atmosphere. In Figure 4, the inert gas supply unit 15 is integrated with the torch portion of the arc discharge device 10, but the inert gas supply unit 15 may be provided separately from the torch portion. Furthermore, the supply of inert gas from the inert gas supply unit may be controlled by providing a supply valve. The inert gas used is not particularly limited, but examples include argon gas and helium gas.

[0029] The control unit 16 controls at least the power supply unit 13 and the drive unit 14. The control unit 16 may also control the inert gas supply unit 15, and the inert gas may be supplied only when a voltage is applied between the electrodes and a plasma arc is generated.

[0030] The control unit 16 controls the drive unit 14 so that the arc length corresponding to the distance x is set so that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face 31a of the exposed conductor portion. With this configuration, even if the diameter d of the end face of the exposed conductor portion of the aluminum wire is large, the entire surface of the end face 31a of the exposed conductor portion can be arc-welded to form a strand-integrated portion at the tip of the exposed conductor portion 31. A specific example of the control is to acquire data on the relationship between the distance x and the irradiation spot diameter of the plasma arc in advance, and then control the distance x so that the irradiation spot diameter of the plasma arc is the same as the diameter d of the end face of the exposed conductor portion of the aluminum wire mounted on the device.

[0031] Furthermore, in addition to controlling the arc length as described above, it is preferable that the control unit 16 controls the drive unit 14 and the power supply unit 13 so that the energy density of the plasma arc remains constant according to the diameter d of the end face of the exposed conductor, by setting the arc current value according to the distance x. Normally, when the arc length is long, if arc discharge is performed under the same current value conditions as when the arc length is short, the energy density of the plasma arc decreases. With this configuration, even when the diameter d of the end face of the exposed conductor of the aluminum wire is large and the arc length is set to be long, the entire surface of the end face 31a of the exposed conductor can be arc welded under the same arc plasma irradiation time conditions to form a strand-integrated portion at the tip of the exposed conductor 31. Specific examples of control include obtaining data in advance on the relationship between distance x and the irradiation spot diameter of the plasma arc, and the current and energy density under those conditions, controlling the distance x so that the irradiation spot diameter of the plasma arc is the same as the diameter d of the end face of the exposed conductor of the aluminum wire mounted on the device, and controlling the current so that the energy density remains constant.

[0032] Furthermore, the inventors conducted further experiments and studies on the relationship between the diameter d of the end face and the distance x in an apparatus with a configuration similar to the aluminum wire manufacturing apparatus of the present invention, where the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor, and arc welding can be suitably performed. As a result, they found that the distance x (mm) with respect to the diameter d (mm) of the end face of the exposed conductor, in which arc welding can be suitably performed, has the following relationship: Formula (I). Formula (I) allows for easy determination and setting of the distance x (arc length) at which the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor when the diameter of the end face of the exposed conductor is d. For this reason, it is preferable from the viewpoint of improving work efficiency that the control unit 14 by the control unit 16 sets the distance x (arc length) from the diameter d of the end face of the exposed conductor of the aluminum wire mounted in the apparatus based on the relationship of Formula (I).

number

[0033] (Shield case) The aluminum wire manufacturing apparatus of the present invention includes a shielding case 20. The shielding case 20 is provided to protect the arc plasma between the electrodes of the arc discharge apparatus from the outside air and / or to shield the generated electromagnetic waves. By including the shielding case 20, the manufacturing of aluminum wires can be carried out more efficiently and safely.

[0034] [Manufacturing method for aluminum electric wire] The present invention provides a method for manufacturing an aluminum electric wire, which has a conductor composed of a plurality of strands made of an aluminum-based material and an insulating coating layer covering the conductor, and an aluminum electric wire having an exposed conductor portion integrated in an exposed state at the terminal portion of the aluminum electric wire, comprising: an exposure step of peeling off the insulating coating layer at the terminal portion of the aluminum electric wire to expose the conductor and form an exposed conductor portion; and an integration step of forming a plasma arc between the end face of the exposed conductor portion and the tip of an electrode of an arc discharge device arranged opposite to the end face, and melting and then solidifying the terminal portions of all the strands constituting the exposed conductor portion with the plasma arc irradiated onto its end face, thereby forming an electrically integrated strand portion at the tip of the exposed conductor portion, wherein the integration step is performed by setting the arc length corresponding to the distance x such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor portion, where x is the distance between the end face of the exposed conductor portion and the tip of the electrode of the arc discharge device, and d is the diameter of the end face of the exposed conductor portion irradiated with the plasma arc.

[0035] The method for manufacturing aluminum wires of the present invention is a method-based representation of the aluminum wire manufacturing apparatus of the present invention described above, and can be carried out using the aluminum wire manufacturing apparatus described above. The method for manufacturing aluminum wires will be described in detail below.

[0036] (Exposure process) The exposure process involves stripping the insulating coating layer at the end of the aluminum wire to expose the conductor and form an exposed conductor section. Through this exposure process, the aluminum wire shown in Figure 3A is modified to produce the aluminum wire shown in Figure 3(B), where the insulating coating layer 4 at the end 30 of the aluminum wire is removed, forming an exposed conductor section 31. The insulating coating layer at the end of the aluminum wire can be stripped using a general-purpose wire stripper.

[0037] (integration process) The integration process, as shown in Figure 6, is performed by forming a plasma arc P between the end face 31a of the exposed conductor portion and the tip of the electrode 11 of the arc discharge device, which is positioned opposite the end face 31a. The plasma arc P irradiated onto the end face 31a of the exposed conductor portion 31 melts the terminal portions of all the strands constituting the exposed conductor portion 31, and then solidifies it, thereby forming an electrically integrated strand portion 34 at the tip of the exposed conductor portion 31. Through the integration process, an aluminum wire with an exposed conductor portion 31 formed at the terminal portion 30 shown in Figure 3(B) is transformed into an aluminum wire with a strand portion 34 formed at the tip of the exposed conductor portion 31, as shown in Figure 5.

[0038] The integration process is performed by setting the arc length corresponding to the distance x such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the conductor exposed portion, where x is the distance between the end face 31a of the exposed conductor portion and the tip of the electrode 11 of the arc discharge device, and d is the diameter of the end face of the exposed conductor portion irradiated with the plasma arc. A specific example of such control is to acquire data on the relationship between the distance x and the irradiation spot diameter of the plasma arc in advance, as described above, and then control the distance x so that the irradiation spot diameter of the plasma arc is the same as the diameter d of the end face of the exposed conductor portion of the aluminum wire mounted on the device.

[0039] As a result, as described in the section on the manufacturing apparatus for aluminum electric wires above, all the individual wires 32 constituting the end face 31a of the exposed conductor portion 31 can be easily welded in a short time with a single arc welding. For example, when connecting to crimp terminals, it is possible to manufacture aluminum electric wires with high connection reliability.

[0040] Furthermore, the integration process is preferably carried out by setting the arc current value according to the distance x so that the energy density of the plasma arc remains constant according to the diameter d of the end face of the exposed conductor. Normally, when the arc length is long, if the arc discharge is performed under the same current value conditions as when the arc length is short, the energy density of the plasma arc decreases. By controlling the current value in this way, even when the diameter d of the end face of the exposed conductor of the aluminum wire is large and the arc length is set to be long, the entire surface of the end face 31a of the exposed conductor can be arc welded under the same arc plasma irradiation time conditions to form an integrated wire section. Specific examples of such control include obtaining data in advance on the relationship between distance x and the irradiation spot diameter of the plasma arc, and the current and energy density under those conditions, and then controlling the distance x so that the irradiation spot diameter of the plasma arc is the same as the diameter d of the end face of the exposed conductor of the aluminum wire mounted on the device, and controlling the current so that the energy density remains constant.

[0041] [Manufacturing method for aluminum wires with crimp terminals] The present invention relates to a method for manufacturing an aluminum wire with a crimp terminal, which is performed using the aluminum wire manufactured in the above-described method for manufacturing an aluminum wire, and is characterized by including a crimping step of crimping and attaching a crimp terminal to the exposed conductor portion of the aluminum wire, including the portion where the strands are integrated.

[0042] Before describing the method for manufacturing aluminum wires with crimp terminals according to the present invention, we will first describe the crimp terminals used in the method for manufacturing aluminum with crimp terminals.

[0043] Figure 7 is a perspective view showing an example of the shape of a crimp terminal before crimping. The crimp terminal 40 is equipped with a wire barrel portion 41 and an insulation barrel portion 42. The wire barrel portion 41 is the part that is crimped to the exposed conductor portion 31 and the strand-integrated portion 34 of the aluminum wire manufactured by the aluminum wire manufacturing method shown in Figure 5, and the insulation barrel portion 42 is the part that is crimped to the insulating coating layer 33. The pin portion 43 has an arbitrary configuration and is a fastening part with a bolt or the like. Figure 7 shows an open barrel type crimp terminal, but other forms such as a closed barrel type may also be used. By being attached to the crimp terminal, the aluminum wire can be connected to other wires with high connection reliability.

[0044] The materials constituting the crimp terminal 40 are appropriately selected depending on the application of the aluminum wire with the crimp terminal and the type of aluminum-based material constituting the conductor. Among these, from the viewpoint of reducing the resistance of the aluminum wire with the crimp terminal, the materials constituting the crimp terminal 40 are preferably copper-based materials including copper and copper alloys, and more preferably pure copper and brass. Furthermore, from the viewpoint of reducing the resistance and weight of the aluminum wire 50 with the crimp terminal, the composition of the crimp terminal 40 is preferably such that it contains 99.0% by mass or more of Al. That is, it is preferable that the crimp terminal 40 be made of pure aluminum.

[0045] (Crimping process) In the crimping process, the crimp terminal is crimped onto the exposed conductor portion of the aluminum wire, including the integrated wire portion. Specifically, the crimping process is carried out as follows: First, the terminal portion 30 of the aluminum wire is placed on the inner surface of the crimp terminal 40. At this time, the position is adjusted so that the exposed conductor portion 31, including the integrated wire portion 34, is at the position of the wire barrel portion 41, and the insulating coating layer 33 is at the position of the insulation barrel portion 42. Next, the wire barrel portion 41 is crimped onto the exposed conductor portion 31, including the integrated wire portion 34. The insulation barrel portion 42 is also crimped onto the insulating coating layer 33. Crimping can be performed using a general crimping tool. In this way, the crimp terminal is attached to the exposed conductor portion 31, including the integrated wire portion 34, of the aluminum wire through the crimping process. A schematic cross-sectional view of the crimp terminal of the manufactured aluminum wire 50 with a crimp terminal is shown in Figure 8. After installation, the wire barrel portion 41 covers the outer circumference of the side of the aluminum electric wire 50 with terminals in an annular shape, along the direction of extension.

[0046] When the exposed conductor portion 31, including the wire integration portion 34, is crimped by the wire barrel portion 41, the wire barrel portion 41 destroys the oxide film (aluminum oxide film, not shown) that was formed on the surface before it was crimped to the crimp terminal 40, and the crimping is performed. Since the wire barrel portion 41 is connected to the exposed conductor portion 31, including the wire integration portion 34, without going through the oxide film, the contact resistance between the wire barrel portion 41 and the exposed conductor portion 31 can be reliably reduced. Furthermore, as described above, since all the wires are electrically connected to each other via the wire integration portion 34 and without going through the aluminum oxide film, the contact resistance between all the wires can be reliably reduced. Therefore, the manufactured aluminum wire with crimp terminal 50 has excellent connection reliability between the exposed conductor portion 31, i.e., the conductor of the aluminum wire, and the wire barrel portion 41 of the crimp terminal 40.

[0047] Thus, the present invention provides a method for manufacturing aluminum wires with crimp terminals that allows for the quick and easy production of aluminum wires with crimp terminals that offer excellent connection reliability between the conductor of the aluminum wire and the crimp terminal. Such aluminum wires with crimp terminals are suitable for use in wire harnesses, preferably automotive wire harnesses, where good connection reliability between the aluminum wire and the crimp terminal is required. [Explanation of symbols]

[0048] 1. Aluminum wire 2, 32 strands 3 conductors 4.33 Insulating coating layer 10. Arc discharge device 11 electrodes 12 Earth Chuck 13 Power supply section 14 Drive Unit 15. Inert gas supply unit 16 Control Unit 20 Shield Cases 30 End section of aluminum wire 31 Exposed conductor portion 31a End face of exposed conductor 34 Wire integration part 40 Crimp terminals 41 Wire barrel section 42 Insulation barrel section 43. Hagoita (Japanese paddle game) section 50 Aluminum wires with crimp terminals A Aluminum wire manufacturing apparatus P Plasma Arc d Diameter of the end face of the exposed conductor w weld u Unwelded part x Distance between the end face of the exposed conductor and the tip of the electrode

Claims

1. A method for manufacturing an aluminum electric wire having a conductor composed of multiple strands made of an aluminum-based material and an insulating coating layer covering the conductor, wherein the terminal portion of the aluminum electric wire has an exposed conductor portion integrated in an exposed state, The process involves removing the insulating coating layer at the terminal end of the aluminum wire to expose the conductor and form an exposed conductor portion, An integration process is performed by forming a plasma arc between the end face of the exposed conductor portion and the tip of an electrode of an arc discharge device positioned opposite the end face, thereby melting and solidifying the terminal portions of all the strands constituting the exposed conductor portion with the plasma arc irradiated onto its end face, and thereby forming an electrically integrated strand portion at the tip of the exposed conductor portion. Includes, The aforementioned integration process is, When x is the distance between the end face of the exposed conductor and the tip of the electrode of the arc discharge device, and d is the diameter of the end face of the exposed conductor that is irradiated with the plasma arc, A method for manufacturing an aluminum electric wire, characterized in that the arc length corresponding to the distance x is set such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor portion.

2. The method for manufacturing an aluminum electric wire according to claim 1, characterized in that the integration step is performed by setting the arc current value to a value corresponding to the distance x such that the energy density of the plasma arc is constant according to the diameter d of the end face of the exposed conductor portion.

3. A method for manufacturing aluminum wires with crimp terminals, A method for manufacturing an aluminum electric wire with a crimp terminal, characterized by including a crimping step of crimping and attaching a crimp terminal to the exposed conductor portion including the strand-integrated portion of the aluminum electric wire described in claim 1 or 2.

4. An aluminum wire manufacturing apparatus having an exposed conductor portion integrated in an exposed state at the terminal end of an aluminum wire having a conductor composed of multiple strands made of an aluminum-based material and an insulating coating layer covering the conductor, Shield case and Arc discharge device and Equipped with, The aforementioned arc discharge device Electrodes and, An earth chuck is installed as a counter electrode at a position opposite to the aforementioned electrode, and grips the exposed conductor portion such that the tip portion, which is the part that melts and solidifies, is exposed to the electrode side. A power supply unit that applies a voltage between the electrode and the earth chuck, A drive unit that adjusts the distance between the electrode and the earth chuck, An inert gas supply unit that supplies inert gas, At least the power supply unit and the control unit that controls the drive unit Equipped with, When x is the distance between the end face of the exposed conductor and the tip of the electrode of the arc discharge device, and d is the diameter of the end face of the exposed conductor that is irradiated with the plasma arc, An aluminum wire manufacturing apparatus characterized in that the drive unit is controlled by the control unit, thereby setting the arc length corresponding to the distance x such that the irradiation spot diameter of the plasma arc is substantially the same as the diameter d of the end face of the exposed conductor.

5. The aluminum wire manufacturing apparatus according to claim 4, characterized in that the drive unit and the power supply unit are controlled by the control unit so that the energy density of the plasma arc is set to an arc current value corresponding to the distance x such that the energy density of the plasma arc is constant according to the diameter d of the end face of the exposed conductor.

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