Electric wire with terminal and manufacturing method of the same

Abstract

To provide an electric wire with a terminal capable of easily cutting off water to a contact part of a conductive part and a terminal of the electric wire, and a manufacturing method of the same.SOLUTION: An electric wire with a terminal comprises: an electric wire having a conductive part and an insulation coating that coats the conductive part; and a terminal including a conductive conductive crimp part that crimps the conductive part of the electric wire. A front surface exposed to an external part of the conductive part of the electric wire and the terminal is continuously coated by a graphene oxide coating film. A manufacturing method of the electric wire with the terminal, comprise the steps of: preparing the electric wire having the conductive part and the insulation coating that coats the conductive part and the terminal having the conductive conductive crimp part that crimps the conductive part of the electric wire, and a fluid dispersion containing the graphene oxide; and immersing the electric wire with the terminal into the fluid dispersion containing the graphene oxide, and continuously coating the front surface exposed to the external part of the conductive part of the electric wire with the terminal and the terminal with a graphene oxide coated film by an electrophoresis deposition method.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electric wire with a terminal and a method for producing the same. [Background technology]

[0002] In terminals of connectors and the like, metal plating such as gold, silver, tin, etc. is generally applied to protect the terminal base material while ensuring the conductivity of the electrical contact. In addition, the connection between the conductor part of the electric wire and the connector terminal is mainly made by "crimping", and the crimped part where the connector terminal and the electric wire come into contact is usually similarly metal plated. However, the metal plating on the surface of the connector terminal and the electric wire material such as copper or aluminum have different ionization tendencies, so dissimilar metals come into contact with each other, and the presence of electrolytes such as water at the boundary between the dissimilar metals may cause galvanic corrosion.

[0003] Various proposals have been made to solve the above problems. Patent Document 1 proposes an electric wire with a terminal, which includes an electric wire having a conductor and an insulating coating surrounding the conductor, and a terminal having a water-stopping part that adheres closely to the outer surface of the insulating coating, a conductor crimping part that crimps the conductor, and a water-stopping holding part that adheres closely to the outer surface side of the water-stopping part and holds the water-stopping part. This configuration can prevent water from entering the part where the conductor of the electric wire and the terminal are connected, thereby preventing galvanic corrosion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6766659 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 requires a process of applying and hardening a waterproofing agent when forming the waterproofing portion. In addition, it is difficult to apply the waterproofing agent only to the crimped portion while avoiding the contact portion (conductive portion) of the connector, and a complex mechanism and process are required to achieve this. In other words, after crimping the conductor portion of the electric wire and the connector terminal to establish electrical continuity, a complex and numerous process steps are required, such as applying and hardening the waterproofing agent, and then crimping and fixing the connector terminal and the insulating portion of the electric wire.

[0006] The present invention has been made in consideration of the problems inherent in the conventional techniques, and an object of the present invention is to provide an electric wire with a terminal that is capable of realizing waterproofing of the contact portion between the conductor portion of the electric wire and the terminal with a simple structure, and a manufacturing method thereof. [Means for solving the problem]

[0007] A terminal-attached wire according to an embodiment of the present invention comprises an electric wire having a conductor portion and an insulating coating covering the conductor portion, and a terminal having a conductive conductor crimping portion that crimps the conductor portion of the electric wire, and the conductor portion of the electric wire and the surfaces exposed to the outside of the terminal are continuously covered with a graphene oxide coating.

[0008] Moreover, a manufacturing method for an electric wire with a terminal according to an embodiment of the present invention includes a step of preparing an electric wire with a terminal, the electric wire including a conductor portion and an insulating coating covering the conductor portion, and a terminal having a conductive conductor crimping portion that crimps the conductor portion of the electric wire, and a dispersion liquid containing graphene oxide; and a step of immersing the electric wire with the terminal in the dispersion liquid containing graphene oxide, and continuously coating the conductor portion of the electric wire with the terminal and the surface exposed to the outside of the terminal with a graphene oxide coating by electrophoretic deposition. Effect of the Invention

[0009] According to the present invention, it is possible to provide an electric wire with a terminal that can realize waterproofing at the contact portion between the conductor portion of the electric wire and the terminal with a simple configuration, and a method for manufacturing the same. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a perspective view showing an example of an electric wire with a terminal according to the present embodiment. [Diagram 2] FIG. 2 is a side view of the electric wire with terminal shown in FIG. [Diagram 3] FIG. 3 is a diagram showing how the electric wire with terminal shown in FIGS. 1 and 2 is continuously coated with a graphene oxide film by electrophoretic deposition. [Figure 4] FIG. 2 is a side view of an electric wire with a terminal on which a graphene oxide coating is formed. [Diagram 5] 1 is an electron microscope photograph showing the state in which a graphene oxide coating is formed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an electric wire with a terminal and a method for manufacturing the same 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 the convenience of explanation and may differ from the actual ratios.

[0012] <Manufacturing method of electric wire with terminal> First, a method for producing an electric wire with terminal of the present embodiment will be described. The method for producing an electric wire with terminal of the present embodiment includes a step of preparing an electric wire with terminal including an electric wire having a conductor portion and an insulating coating covering the conductor portion, and a terminal having a conductive conductor crimping portion for crimping the conductor portion of the electric wire, and a dispersion liquid containing graphene oxide. The method also includes a step of immersing the electric wire with terminal in the dispersion liquid containing graphene oxide, and continuously covering the conductor portion of the electric wire with terminal and the surface exposed to the outside of the terminal with a graphene oxide coating by electrophoretic deposition.

[0013] In a typical electric wire with a terminal, only the crimped portion, excluding the contact portion between the conductor portion of the electric wire and the terminal, is coated with an insulating resin or the like. In contrast, in this embodiment, graphene oxide is used as the material, and a graphene oxide coating is formed continuously not only at the crimped portion but also at the contact portion between the conductor portion of the electric wire and the terminal by electrophoretic deposition. Graphene oxide selectively adheres only to the conductive portion exposed to the outside when an electric field is generated, and does not adhere to the insulating coating portion of the electric wire. Therefore, unlike the conventional method, a process of removing an excess film formed on the insulating coating after processing is not necessary. Therefore, in this embodiment, it is possible to achieve waterproofing of the contact portion between the conductor portion of the electric wire and the terminal through a simple process.

[0014] 1 and 2 show an example of an electric wire with a terminal. The electric wire with a terminal 10 shown in FIG. 1 and FIG. 2 shows a state in which an electric wire 1 having a conductor portion 2 consisting of multiple core wires and an insulating coating 3 is attached to a terminal 4. The terminal 4 has a ring terminal 5 at an end thereof and a wire clamping portion 7 at a rear portion thereof. Between the ring terminal 5 and the wire clamping portion 7, there is a conductor crimping portion 6 for crimping and fixing the conductor portion 2 of the electric wire 1. The ring terminal 5 has a ring hole, and when connecting to a mating connection terminal, a pin or a bolt is inserted into the ring hole to connect and fix. In addition, the wire clamping portion 7 is crimped with the electric wire 1 placed on the terminal 4, thereby fixing the insulating coating 3 of the electric wire 1. Furthermore, in the conductor crimping portion 6, the conductor portion 2 of the electric wire 1 is fixed in a crimped state, and the terminal 4 and the conductor portion 2 of the electric wire 1 are in a conductive state.

[0015] In this embodiment, a graphene oxide coating is formed on the electric wire with terminal as described above by employing an electrophoretic deposition method. That is, the electric wire with terminal is immersed in a dispersion liquid containing graphene oxide (hereinafter also referred to as a "graphene oxide dispersion liquid"), and a graphene oxide coating is formed by electrophoretic deposition with the electric wire with terminal serving as the anode. In this way, a graphene oxide coating is formed only on the conductor portion of the electric wire with terminal. The conductor portion of the electric wire with terminal is a portion of the electric wire with terminal that is conductive, and includes the terminal itself and the conductor portion of the electric wire.

[0016] Electrophoretic deposition is a technique used to form a film on the surface of a component, and is a film formation method in which, for example, particles are dispersed in water to prepare a dispersion liquid, electrodes are inserted into the dispersion liquid, and a voltage is applied to cause the charged particles in the dispersion liquid to migrate and deposit on the electrodes. Since electrophoretic deposition does not require heat treatment and can form a film in a non-vacuum and at room temperature, it is possible to easily form a graphene oxide film at low cost.

[0017] In this embodiment, when forming a graphene oxide coating on the conductor surface of the terminal-attached electric wire by electrophoretic deposition, a dispersion liquid containing graphene oxide having a negative zeta potential can be used. Then, when a process by electrophoretic deposition is performed with the terminal-attached electric wire on the anode side, graphene oxide moves by electrophoresis toward the terminal-attached electric wire on the anode side and is deposited on the terminal of the terminal-attached electric wire and the surface of the conductor part of the electric wire. Furthermore, in the electrophoretic deposition method, graphene oxide moves by Coulomb force due to an external electric field and is firmly deposited on the terminal of the terminal-attached electric wire and the surface of the conductor part of the electric wire. Therefore, graphene oxide can be deposited as a film not only in a planar form as in the spin coating method, but also on a complex form of the conductor part surface.

[0018] FIG. 3 shows a state in which a treatment by electrophoretic deposition is performed in this embodiment. The apparatus shown in FIG. 3 includes an electrophoretic tank 30 filled with a graphene oxide dispersion liquid 22 containing graphene oxide, and a power source 12. In the electrophoretic tank 30, graphene oxide 24 is dispersed in a dispersion medium. The negative electrode of the power source 12 is connected to the cathode 16 via a wiring 14. The positive electrode of the power source 12 is connected to the conductor part 2 of the electric wire with terminal 10 via a wiring 18. In this state, when a voltage is applied from the power source 12 to the electric wire with terminal 10 on the anode side and the cathode 16 to perform a treatment by electrophoretic deposition, graphene oxide having a negative zeta potential moves toward the electric wire with terminal 10 on the anode side. Due to this behavior, graphene oxide is deposited on the surfaces exposed to the outside of the terminal 4 and the conductor part 2, which are the conductor parts of the electric wire with terminal 10, to form a film. In this manner, a graphene oxide coating is formed on the conductor part of the electric wire with terminal 10.

[0019] 4 shows a state in which a graphene oxide coating is formed on the conductor portion of the electric wire with terminal 10. That is, a graphene oxide coating 26 is formed continuously on the surface exposed to the outside of the terminal 4 of the electric wire with terminal 10 and on the conductor portion 2 of the electric wire with terminal 10. The state in which a graphene oxide coating is formed on the surface of a terminal is shown in an electron microscope photograph in Fig. 5. Fig. 5 shows a state in which a graphene oxide coating A is formed on the surface of a terminal 4. The graphene oxide coating shown in Fig. 5 is an example formed to a thickness of 5 nm with a graphene oxide dispersion concentration of 40 mg / L, an applied voltage of 3 V, and a film formation time of 1 minute.

[0020] In this embodiment, it is preferable to select a dispersion medium that does not dissolve the insulating coating of the electric wire as the dispersion medium used for preparing the graphene oxide dispersion. This is because, as described above, when forming the graphene oxide film, the insulating coating of the electric wire is also immersed in the graphene oxide dispersion. For example, materials such as polyvinyl chloride and polyethylene are used as the insulating coating of the electric wire, and a dispersion medium that does not dissolve these materials can be selected from, for example, water, ethanol, propanol, isopropanol, acetone, dimethylformamide, etc. In this embodiment, the concentration of graphene oxide in the graphene oxide dispersion is preferably 0.001 to 0.1 mass %, and more preferably 0.005 to 0.01 mass %, from the viewpoint of forming a graphene oxide coating with an appropriate thickness.

[0021] In addition to graphene oxide, a pH buffer solution, a preservative, and the like can be added to the graphene oxide dispersion.

[0022] The graphene oxide-containing dispersion can be prepared by adding graphene oxide to a measured amount of water. The dispersion may be prepared by dispersing graphene oxide in water, or may be a commercially available graphene oxide dispersion.

[0023] Before forming a graphene oxide coating on the electric wire with terminal, it is preferable to remove an oxide film on the surface of the conductor of the electric wire with terminal. The method for removing the oxide film is not particularly limited, and the oxide film may be removed physically by polishing or the like, or may be removed chemically by using a chemical solution. The chemical solution can be appropriately selected depending on the characteristics of the oxide film. The chemical solution may be, for example, an acidic solution such as sulfuric acid, hydrochloric acid, or nitric acid.

[0024] Before forming a graphene oxide coating on the electric wire with terminal, the conductor surface of the electric wire with terminal may be smoothed. The method for smoothing the conductor surface is not particularly limited, and the conductor surface may be smoothed by polishing or the like. Among the polishing methods, it is preferable to smooth the surface of the conductive base material by chemical mechanical polishing. Chemical mechanical polishing (CMP) is a method in which a chemical solution such as an acid or base is applied to the conductor surface, and the conductor surface is mechanically polished by abrasive particles or the like to smooth the conductor surface. According to CMP, the conductor surface can be modified by the chemical solution so that it is easier to polish, which makes mechanical polishing easier and allows a smooth and good surface to be finished.

[0025] In this embodiment, as described above, the graphene oxide is moved by the Coulomb force caused by the external electric field by the electrophoretic deposition method, and is firmly deposited on the surface of the electric wire with terminal. Therefore, the adhesion of the graphene oxide can be adjusted by the Coulomb force. Here, when the external electric field is E (V / m) and the electrolysis is Q (C), the Coulomb force F (N) is given by F = qE. That is, the Coulomb force that the graphene oxide receives in the dispersion liquid can be controlled by the applied voltage or the charge of the graphene oxide. In addition, the charge of the graphene oxide can be adjusted by the zeta potential, that is, the pH of the dispersion liquid. Therefore, in order to increase the Coulomb force in order to improve the adhesion of the graphene oxide coating to the electric wire with terminal, it can be achieved by increasing the applied voltage and / or decreasing the pH of the dispersion liquid.

[0026] For these reasons, the voltage applied to each of the anode and cathode is preferably 1 to 100 V. In the electrophoresis tank, the distance between each of the anode and cathode electrodes can be set appropriately.

[0027] The voltage application time varies depending on the voltage, but is preferably 0.1 to 4 minutes. By setting the application time to 0.1 minutes or more, a good graphene oxide coating can be formed on the conductive base material. Furthermore, by setting the application time to 4 minutes or less, the thickness of the graphene oxide coating can be reduced. The voltage application time is more preferably 1 minute or more. Furthermore, the voltage application time is more preferably 3 minutes or less. Note that the longer the voltage application time, the thicker the graphene oxide coating becomes.

[0028] As described above, a graphene oxide coating can be formed on an electric wire with a terminal by the manufacturing method of an electric wire with a terminal of the present embodiment. In addition, in the present embodiment, a complicated process of applying and curing a waterproofing agent or an anticorrosive agent is not required. In addition, a complicated process or mechanism such as applying an anticorrosive (water-stopping) agent only to the crimped portion while avoiding the contact portion (conductive portion) of the conductor portion of the electric wire and the terminal can be subjected to anticorrosion treatment at the same time as the crimped portion. Furthermore, after the conductor portion of the electric wire is crimped and fixed to the terminal, the conductor portion of the electric wire can be connected to the anode in the electrophoretic deposition method to form an electric circuit required for film formation. Therefore, the circuit formation (power supply mechanism and parts (such as a clip for applying an electric field)) used in forming a film only on the conventional terminal parts by the electrophoretic deposition method is not required.

[0029] <Wire with terminal> The electric wire with terminal of the present embodiment includes an electric wire having a conductor portion and an insulating coating covering the conductor portion, and a terminal having a conductive conductor crimping portion that crimps the conductor portion of the electric wire. The conductor portion and the conductor crimping portion of the electric wire are continuously covered with a graphene oxide coating.

[0030] The electric wire with terminal of this embodiment can be manufactured by the manufacturing method of the electric wire with terminal of this embodiment described above. That is, as shown in Fig. 4, a graphene oxide coating is selectively formed only on the conductor part 2 and the terminal 4 of the electric wire with terminal 10, and the presence of the graphene oxide coating makes the contact part between the conductor part 2 of the electric wire 1 and the terminal 4 waterproof, thereby preventing galvanic corrosion.

[0031] In this embodiment, the terminal may be a splice terminal or the like in addition to a connector terminal as shown in Fig. 1. A splice terminal can cover exposed electric wires collectively, and can prevent galvanic corrosion that occurs at the crimped portion.

[0032] 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]

[0033] 1 electric wire 2 Conductor 3. Insulation coating 4 Terminals 6 Conductor crimping section 7 Wire clamping part 10 Wires with terminals 12 Power supply 14 18 Wiring 22 Graphene oxide dispersion 24 Graphene oxide 30 Electrophoresis tank

Claims

1. An electric wire having a conductor portion and an insulating coating covering the conductor portion; a terminal having a conductive conductor crimping portion that crimps a conductor portion of the electric wire; Equipped with An electric wire with a terminal, wherein a conductor portion of the electric wire and a surface exposed to an outside of the terminal are continuously covered with a graphene oxide coating.

2. The terminal-attached electric wire according to claim 1 , wherein the terminal is a connector terminal or a splice terminal.

3. A step of preparing an electric wire with a terminal, the electric wire including a conductor portion and an insulating coating covering the conductor portion, and a terminal having a conductive conductor crimping portion that crimps the conductor portion of the electric wire, and a dispersion liquid including graphene oxide; a step of immersing the electric wire with terminal in a dispersion liquid containing the graphene oxide, and continuously covering a conductor portion of the electric wire with terminal and an externally exposed surface of the terminal with a graphene oxide coating by an electrophoretic deposition method; A method for manufacturing an electric wire with a terminal, comprising:

Images