JP7687872B2 - Electric wire, electrical connection part using the same, electric wire with terminal, and method for manufacturing the electric wire - Google Patents

Description

The present invention relates to an electric wire, an electrical connection part using the electric wire, an electric wire with a terminal, and a method for manufacturing the electric wire.

Conventionally, connector terminals are plated with metals such as gold, silver, and tin to protect the base material from corrosion while ensuring the conductivity of the electrical contacts. In addition, a reaction suppression layer such as a nickel layer may be provided between the base material and the metal plating to suppress reaction between the base material and the metal plating of the connector terminal.

In recent years, as electronic devices have become more sophisticated, digital signals with high frequencies of several GHz to several tens of GHz have come to be used. Patent Document 1 discloses a method for manufacturing electrical contacts that enables stable low inductive reactance in the transmission of high frequency signals. This method includes a step of forming a nickel-phosphorus alloy plating film on the surface of a copper plating film formed on the surface of a base material, and a step of forming a surface plating film on the surface of the nickel-phosphorus alloy plating film. The nickel-phosphorus alloy plating film is made non-magnetic by setting the phosphorus content of the nickel-phosphorus alloy plating film within a specified range.

Patent No. 5966506

Conventional electrical contacts have a multi-layer structure that includes a copper plating film, a nickel-phosphorus alloy plating film, and a surface plating film, and the material ratios are carefully controlled to make the nickel-phosphorus alloy plating film non-magnetic. Furthermore, conventional technology uses expensive gold as the surface plating film. Therefore, electrical contacts manufactured using conventional methods may be expensive to manufacture.

On the other hand, when silver or tin is used instead of gold for the surface plating film, the surface of the surface plating is covered with a non-conductive natural oxide film. Therefore, from the viewpoint of electrical conductivity, it is preferable to provide a mechanism for applying a large load to break or peel off the natural oxide film. However, providing such a mechanism may result in a deterioration in the quality of the high frequency signal due to the shape of the connector terminal.

Thus, although metal plating used on electrical contacts is useful for ensuring conductivity and protecting the base material, it can lead to increased manufacturing costs or reduced quality of high-frequency signals.

The present invention was made in consideration of the problems inherent in the conventional technology. The object of the present invention is to provide an electric wire that uses a graphene film to enable electrical connection to a mating electric wire without metal plating on the electrical contacts, as well as an electrical connection part, an electric wire with terminals, and a method for manufacturing the electric wire.

The electric wire according to this embodiment of the present invention comprises a conductor and an insulating layer that covers the conductor, and the axial end face of the conductor is covered with a graphene film.

An electrical connection component according to another aspect of the present invention includes a pair of electric wires including a conductor and an insulating layer covering the conductor, and the axial end faces of the conductor in each of the pair of electric wires are covered with a graphene film. The graphene films in each of the pair of electric wires are in contact with each other.

An electric wire with terminal according to another aspect of the present invention includes a conductor and an insulating layer covering the conductor, and the axial end face of the conductor is covered with a graphene film. The electric wire with terminal includes a terminal provided on the electric wire so that the graphene film on the end face contacts a mating electric wire, thereby electrically connecting the electric wire and the mating electric wire.

A method for manufacturing an electric wire according to another aspect of the present invention is a method for manufacturing an electric wire having a conductor and an insulating layer that covers the conductor, in which the axial end face of the conductor is covered with a graphene film using an electrophoretic deposition method.

According to the present invention, by using a graphene film, it is possible to provide an electric wire that can be electrically connected to a mating electric wire without using metal plating on the electrical contacts, an electrical connection part using the same, an electric wire with terminals, and a method for manufacturing the electric wire.

FIG. 1 is a perspective view showing an example of an electric wire according to an embodiment of the present invention. 1 is a cross-sectional view showing an example of an electric wire according to an embodiment of the present invention. FIG. 2 is a perspective view showing an example of a state before a pair of electric wires are connected. FIG. 4 is a side view showing an example of a state after a pair of electric wires are connected. 5A to 5C are schematic diagrams illustrating an example of a method for producing the electric wire according to the present embodiment. FIG. 2 is a cross-sectional view showing an example of an electric wire with a terminal according to the present embodiment. FIG. 4 is a cross-sectional view showing another example of an electric wire with a terminal according to the present embodiment. FIG. 2 is a cross-sectional view showing an example of a state before an electric wire with a first terminal and an electric wire with a second terminal are connected. FIG. 4 is a cross-sectional view showing an example of a state after a first terminal-fitted wire and a second terminal-fitted wire are connected to each other.

The electric wire and its manufacturing method, electrical connection parts, and electric wire with terminal according to this embodiment will be described in detail below 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.

[Electric wire]
First, an electric wire 10 according to the present embodiment will be described with reference to Fig. 1 and Fig. 2. As shown in Fig. 1 and Fig. 2, the electric wire 10 according to the present embodiment includes a conductor 11 and an insulating layer 12 that covers the conductor 11.

The conductor 11 extends in the axial direction. The conductor 11 may be composed of only one strand, may be a bunched strand in which multiple strands are twisted together, or may be a composite strand in which multiple bunched strands are twisted together. The diameter of the conductor 11 may be 0.2 mm or more, 1 mm or more, 3 mm or more, or 5 mm or more. The diameter of the conductor 11 may be 30 mm or less, 25 mm or less, or 20 mm or less. The conductor 11 may contain at least one metal selected from the group consisting of copper, copper alloy, aluminum, aluminum alloy, etc.

The insulating layer 12 covers the conductor 11. Specifically, the insulating layer 12 covers the outer surface of the conductor 11 in the circumferential direction so as to surround it. The insulating layer 12 also covers the conductor 11 in the axial direction. The axial end of the conductor 11, which is the outer surface in the radial direction perpendicular to the axial direction, may be covered with the insulating layer 12 so as not to be exposed, or a part of the insulating layer 12 may be stripped off to expose the outer surface. In this embodiment, the outer surface of the conductor 11 is covered with the insulating layer 12 in the circumferential direction up to the end face in the axial direction of the conductor 11. This allows the end of the conductor 11 to be protected by the insulating layer 12, and there is no need to strip off a part of the insulating layer 12.

The thickness of the insulating layer 12 may be 0.2 mm or more, 0.4 mm or more, or 0.6 mm or more. The thickness of the insulating layer 12 may be 2 mm or less, 1.9 mm or less, or 1.8 mm or less. The insulating layer 12 may contain a resin composition.

The resin composition may contain at least one of polyolefin and polyvinyl chloride. The polyolefin may contain at least one resin selected from the group consisting of polyethylene, polypropylene, ethylene copolymers, and propylene copolymers. The resin in the resin composition may be crosslinked by irradiation or the like. The resin composition may contain various additives such as a flame retardant and an antioxidant.

The electric wire 10 may further include a shield layer that covers the insulating layer 12, and a sheath layer that further covers the shield layer. The shield layer can suppress the emission of electromagnetic waves from the conductor 11. The shield layer may be a metal foil or a mesh-like metal member. The sheath layer may contain a resin composition. The composition of the resin composition of the sheath layer may be the same as or different from the resin composition of the insulating layer 12.

The axial end face of the conductor 11 is covered with a graphene film 13. The graphene film 13 may be graphene or a stack of graphene. Graphene is a conductive material made from an inexpensive carbon source. Graphene is a film-like substance having a thickness of one atom and a planar hexagonal lattice structure formed by ^sp2 bonds between carbon atoms. Graphene is a conductive material and does not have ferromagnetism, so it is possible to suppress deterioration in the quality of high-frequency signals of several GHz to several tens of GHz. In addition, graphene is a nonmetal and is therefore not easily oxidized, making it suitable as an electrical contact.

The number of graphene layers contained in the graphene film 13 may be three or more. By using three or more layers of graphene, it is possible to prevent the intrusion of oxygen and water and suppress the movement of metal atoms due to ion migration. There is no particular upper limit on the number of graphene layers. The number of graphene layers may be 100 layers or less, 50 layers or less, or 30 layers or less.

The thickness of the graphene film 13 may be 0.9 nm to 10 μm from the viewpoint of contact reliability. The thickness of the graphene film 13 can be obtained by observing a cross section of the graphene film 13 with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) and measuring the thickness.

Next, a method for manufacturing an electrical connection part 1 from an electric wire 10 will be described with reference to Figures 3 and 4. Figure 3 is a perspective view showing an example of a state before a pair of electric wires 10 are connected. Figure 4 is a side view showing an example of a state after a pair of electric wires 10 are connected.

First, as shown in FIG. 3, a pair of electric wires 10 including an electric wire 10 and a mating electric wire 10 is prepared. The mating electric wire 10 is the same as the electric wire 10, and includes a conductor 11 and an insulating layer 12 that covers the conductor 11. The axial end face of the conductor 11 in each of the pair of electric wires 10 is covered with a graphene film 13. Then, the pair of electric wires 10 are arranged so that the graphene films 13 of each of the pair of electric wires 10 face each other. Next, as shown in FIG. 4, the pair of electric wires 10 are brought close to each other in the axial direction, and the graphene films 13 of each of the pair of electric wires 10 are brought into contact with each other, thereby forming an electrical connection part 1.

As described above, the electric wire 10 according to this embodiment includes a conductor 11 and an insulating layer 12 that covers the conductor 11, and the axial end face of the conductor 11 is covered with a graphene film 13.

The electrical connection part 1 according to this embodiment includes a pair of electric wires 10 including a conductor 11 and an insulating layer 12 that covers the conductor 11. The axial end faces of the conductor 11 in each of the pair of electric wires 10 are covered with a graphene film 13. The graphene films 13 in each of the pair of electric wires 10 are in contact with each other.

Since the graphene film 13 is conductive, the conductors 11 of a pair of electric wires 10 are electrically connected via the graphene film 13 by directly contacting the graphene films 13 with each other. Therefore, according to the electric wire 10 of this embodiment, by using the graphene film 13, it is possible to electrically connect with the mating electric wire 10 without using metal plating for the electrical contacts.

Normally, metals such as copper and aluminum used for the conductor 11 have a natural oxide film formed on the surface, so that a good electrical connection cannot be obtained by simply butting the end faces of the conductor 11 together as in this embodiment. Even if the end faces of the conductor 11 are silver-plated or tin-plated, a good electrical connection cannot be obtained because it is not easy to destroy or remove the natural oxide film by simply butting the end faces of the conductor 11 together. Furthermore, gold plating, which is less likely to produce a natural oxide film, requires a ferromagnetic nickel layer as a reaction suppression layer between the gold plating and the connector terminal base material such as copper, which may degrade high-frequency signals.

On the other hand, the electric wire 10 according to the present embodiment allows electrical connection without using metal-plated connector terminals, eliminating the need for expensive materials such as gold plating, and a removal mechanism for removing the natural oxide film of metal plating such as silver and tin. In addition, since the graphene film 13 is not ferromagnetic, deterioration of the quality of high-frequency signals such as several GHz to several tens of GHz can be suppressed.

[Method of manufacturing electric wire]
Next, a method for manufacturing the electric wire 10 according to the present embodiment will be described with reference to Fig. 5. In the method for manufacturing the electric wire 10 according to the present embodiment, an end face in the axial direction of the conductor 11 is covered with the graphene film 13 by using an electrophoretic deposition method (EPD method).

Figure 5 shows an electrophoretic device 50 used in the electrophoretic deposition method. The electrophoretic device 50 includes an electrophoretic tank 51, a dispersion liquid 52, a cathode 53, and an anode 54. The electrophoretic tank 51 contains the dispersion liquid 52. At least a portion of the cathode 53 and the anode 54 is immersed in the dispersion liquid 52. The cathode 53 and the anode 54 are connected to a DC power source 55. In this embodiment, the conductor 11 of the electric wire 10 is used as the anode 54.

The dispersion liquid 52 contains graphene or graphene oxide. The dispersion medium of the dispersion liquid 52 may contain water. The concentration of graphene or graphene oxide in the dispersion liquid 52 may be 0.001 mg/L or more and 500 mg/L or less from the viewpoint of forming a graphene film 13 or a graphene oxide film of an appropriate thickness. The concentration may be 0.005 mg/L or more and 50 mg/L or less. In addition to graphene or graphene oxide, the dispersion liquid 52 may contain various additives such as a pH buffer solution and a preservative.

The cathode 53 may be a soluble cathode or an insoluble cathode. The soluble cathode may be a copper-containing metal such as phosphorus-containing copper, electrolytic copper, or oxygen-free copper, or a nickel-containing metal such as nickel or a nickel alloy. The insoluble cathode may be carbon, platinum, or platinum-coated titanium, etc.

Before immersing the conductor 11 of the electric wire 10 in the dispersion liquid 52, the natural oxide film on the end surface may be removed. The natural oxide film may be physically removed by polishing or the like, or may be chemically removed by using a chemical solution. The chemical solution may be appropriately selected depending on the characteristics of the natural oxide film. The chemical solution may be, for example, an acidic solution such as sulfuric acid, hydrochloric acid, or nitric acid.

In the electrophoretic deposition method, when a voltage is applied between the cathode 53 and the anode 54 by the DC power supply 55, the graphene or graphene oxide in the dispersion liquid 52 migrates toward the conductor 11, which is the anode 54, and is deposited on the axial end face of the conductor 11. As a result, a graphene film 13 or graphene oxide film is formed on the end face of the conductor 11.

After the graphene film 13 or graphene oxide film is formed on the end face of the conductor 11, the electric wire 10 may be pulled out of the dispersion liquid 52 and then dried. The drying temperature when drying the graphene film 13 or graphene oxide film may be 80°C to 120°C. The drying time may be 5 minutes to 30 minutes. The drying atmosphere may be an inert gas atmosphere such as nitrogen to prevent oxidation of the conductor 11 of the electric wire 10.

When a graphene oxide film is formed on the end face of the conductor 11, the graphene oxide film may be reduced to produce the graphene film 13. The graphene oxide film may be reduced by a known method such as a chemical reduction process, a thermal reduction process, or a photoreduction process.

The thickness of the graphene film 13 or graphene oxide film can be controlled by adjusting the concentration of graphene or graphene oxide in the dispersion liquid 52, the voltage between the electrodes of the cathode 53 and the anode 54, and the time for which the voltage is applied. For example, the thickness of the graphene film 13 or graphene oxide film can be increased by increasing the voltage between the electrodes or increasing the time for which the voltage is applied. On the other hand, the thickness of the graphene film 13 or graphene oxide film can be decreased by decreasing the voltage between the electrodes or shortening the time for which the voltage is applied.

In this embodiment, the conductor 11 of the electric wire 10 is used as the anode 54, and a graphene film or graphene oxide film is formed on the end surface of the conductor 11 by electrophoretic deposition. However, the conductor 11 of the electric wire 10 can be used as the cathode 53 by adjusting the pH of the dispersion liquid 52 and changing the zeta potential of the graphene or graphene oxide in the dispersion liquid 52 from negative to positive.

As described above, the method for manufacturing the electric wire 10 according to this embodiment is a method for manufacturing an electric wire 10 including a conductor 11 and an insulating layer 12 that covers the conductor 11, and uses electrophoretic deposition to cover the axial end face of the conductor 11 with a graphene film 13.

The electrophoretic deposition method does not require heat treatment and can form a film in a non-vacuum and at room temperature, so the graphene film 13 can be easily formed on the end surface of the conductor 11 at low cost.

In this embodiment, an example of coating the end face of the conductor 11 with the graphene film 13 using the electrophoretic deposition method has been described, but the method of coating the end face of the conductor 11 with the graphene film 13 is not limited to this. For example, the end face of the conductor 11 may be coated with the graphene film 13 using a CVD (chemical vapor deposition) method, a transfer method, or a synthesis method. In the transfer method, a pressing member having a graphene film 13 disposed on its surface may be pressed against the end face of the conductor 11 to transfer the graphene film 13 to the end face of the conductor 11. In the synthesis method, the graphene film 13 may be synthesized by heating the end face of the conductor 11 on which an organic material such as polymethyl methacrylate and a carbon source such as graphene oxide are disposed, using a laser. By these methods, the end face of the conductor 11 can be coated with the graphene film 13.

[Terminal wire]
Next, the electric wire with terminal 100 according to the present embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a cross-sectional view showing an electric wire with a first terminal 200 which is an example of the electric wire with terminal 100. Fig. 7 is a cross-sectional view showing an electric wire with a second terminal 300 which is an example of the electric wire with terminal 100.

First, the electric wire with a first terminal 200 according to the present embodiment will be described with reference to FIG. 6. As shown in FIG. 6, the electric wire with a first terminal 200 includes an electric wire 10 and a terminal 210 (terminal 110). The terminal 210 is provided on the electric wire 10 such that the graphene film 13 on the end surface contacts the mating electric wire 10, which is the electric wire 10 of the electric wire with a second terminal 300, and the electric wire 10 and the mating electric wire 10 are electrically connected. Specifically, the graphene film 13 is provided on the end surface of the conductor 11 so as not to contact the terminal 210. The terminal 210 is provided on the electric wire 10 such that the graphene film 13 is visible from the outside of the terminal 210. The electric wire 10 is provided so as to be able to swing in the axial direction relative to the terminal 210. The terminal 210 includes a first holding portion 220 and a first housing 230.

The first holding portion 220 holds the electric wire 10 by clamping the outer peripheral surface of the electric wire 10. The first holding portion 220 includes a clamping portion 221, a restricting portion 222, and a pressing portion 223.

The clamping portion 221 is provided to clamp the alignment portion 321 of the electric wire with second terminal 300. The clamping portion 221 is disposed near the end of the conductor 11 on which the graphene film 13 is provided. The clamping portion 221 surrounds the electric wire 10 along the circumferential direction of the electric wire 10 with a space therebetween. The clamping portion 221 is provided so that the cylindrical wall portion of the alignment portion 321 of the electric wire with second terminal 300 can be inserted into the space between the clamping portion 221 and the electric wire 10. The radial positions of the electric wire with first terminal 200 and the electric wire with second terminal 300 are adjusted by clamping the alignment portion 321 with the clamping portion 221.

The clamping portion 221 may include a protrusion 221a disposed in a position facing the electric wire 10 and protruding toward the electric wire 10. The protrusion 221a contacts the outer surface of the core-aligning portion 321, thereby ensuring a connection between the electric wire with the first terminal 200 and the electric wire with the second terminal 300 so that the electric wire with the second terminal 300 does not come off the electric wire with the first terminal 200.

The restricting portion 222 surrounds the electric wire 10 along the outer surface of the electric wire 10 of the electric wire with the first terminal 200. Therefore, the restricting portion 222 can prevent the electric wire 10 of the electric wire with the first terminal 200 from bending when the electric wire 10 of the electric wire with the first terminal 200 is pressed axially by the mating electric wire 10 of the electric wire with the second terminal 300.

The pressing portion 223 is provided at the end of the first holding portion 220 opposite to the clamping portion 221. When the electric wire 10 is pressed in the axial direction by the mating electric wire 10, the pressing portion 223 applies a force to the electric wire 10 to push back the mating electric wire 10. Specifically, the pressing portion 223 includes a housing portion 223a and an elastic body 223b housed in the housing portion 223a. The housing portion 223a surrounds the outer periphery of the electric wire 10 and has a space in which the electric wire 10 and the elastic body 223b are arranged. In this embodiment, a coil spring is used as the elastic body 223b, and the coil spring is provided so as to be wound around the electric wire 10. One end of the coil spring is fixed to the electric wire 10 via the elastic body fixing portion 223c.

As shown in FIG. 8, when the electric wire 10 of the electric wire with first terminal 200 is not pressed against the mating electric wire 10, the coil spring abuts against a pair of inner walls that face each other in the axial direction of the housing portion 223a. The elastic body fixing portion 223c is disposed at a position close to the inner wall of the pair of facing inner walls that is provided on the graphene film 13 side.

As shown in FIG. 9, when the electric wire 10 of the electric wire with first terminal 200 is pressed against the mating electric wire 10, one end of the coil spring abuts against the inner wall of the pair of inner walls that is farther from the graphene film 13. Meanwhile, the other end of the coil spring is fixed to the electric wire 10 via the elastic body fixing part 223c. Therefore, when the electric wire 10 is pressed in the axial direction, the coil spring is compressed. Due to the restoring force of the elastic body, the pressing part 223 pushes back the mating electric wire 10 by the electric wire 10, so that the electric wire 10 and the mating electric wire 10 can be maintained in a state pressed against each other via the graphene film 13.

The first housing 230 covers the outer surface of the first holding portion 220. The second joint portion 231 of the first housing 230 is joined to the first joint portion 224 provided on the radial outer surface of the first holding portion 220.

Next, the electric wire with second terminal 300 according to this embodiment will be described with reference to FIG. 7. As shown in FIG. 7, the electric wire with second terminal 300 includes an electric wire 10 and a terminal 310 (terminal 110). The terminal 310 is provided on the electric wire 10 such that the graphene film 13 on the end surface contacts the mating electric wire 10, which is the electric wire 10 of the electric wire with first terminal 200, and the electric wire 10 and the mating electric wire 10 are electrically connected. Specifically, the graphene film 13 is provided on the end surface of the conductor 11 so as not to contact the terminal 310. The terminal 310 is provided on the electric wire 10 such that the graphene film 13 is visible from the outside of the terminal 310. The terminal 310 includes the electric wire 10, a second holding portion 320, and a second housing 330.

The second holding portion 320 holds the electric wire 10 by clamping the outer peripheral surface of the electric wire 10. The second holding portion 320 includes a core alignment portion 321 and an electric wire fixing portion 322.

The core-aligning section 321 surrounds the outer circumference of the electric wire 10 and adjusts the radial position of the mating electric wire 10 relative to the electric wire 10 so that the mating electric wire 10 is electrically connected to the electric wire 10 when the mating electric wire 10 is brought close to the electric wire 10 in the axial direction and brought into contact with the electric wire 10. The core-aligning section 321 adjusts the connection position of the electric wire 10 and the mating electric wire 10, so that the electrical connection between the electric wire 10 and the mating electric wire 10 can be made more reliable.

The alignment portion 321 is a cylindrical member that extends in the axial direction along the outer surface of the electric wire 10 and has an inner diameter larger than the outer diameter of the electric wire 10. The alignment portion 321 includes a covered portion 321a and a non-covered portion 321b that is formed continuously in the axial direction with the covered portion 321a. The covered portion 321a covers the outer surface of the electric wire 10 in the circumferential direction to suppress the electric wire 10 from moving radially within the alignment portion 321. The non-covered portion 321b is provided so that the counterpart electric wire 10 can be inserted, and the electric wire 10 of the second terminal-attached electric wire 300 is not disposed in the space surrounded by the non-covered portion 321b. The alignment portion 321 is formed such that the covered portion 321a and the non-covered portion 321b are continuously formed in the axial direction. Therefore, when the mating wire 10 is inserted into the core-aligning section 321, the radial position of the mating wire 10 is adjusted to be the same as the radial position of the wire 10 of the second terminal-attached wire 300.

The wire fixing portion 322 clamps the wire 10 from the outer surface, fixing the wire 10 of the wire with second terminal 300 so that it does not swing axially relative to the terminal 310. This makes it difficult for the wire 10 of the wire with second terminal 300 to move axially even if it is pressed by the mating wire 10. This makes it easy for the wire 10 of the wire with second terminal 300 to maintain a state in which it presses the mating wire 10 in the axial direction.

The second housing 330 covers the outer surface of the second holding portion 320. The fourth joint portion 331 of the second housing 330 is joined via the third joint portion 323 provided on the radial outer surface of the second holding portion 320.

Next, a method for manufacturing an electrical connection part 1 from an electric wire with a first terminal 200 and an electric wire with a second terminal 300 will be described with reference to Figures 8 and 9. Figure 8 is a cross-sectional view showing an example of a state before the electric wire with a first terminal 200 and the electric wire with a second terminal 300 are connected. Figure 9 is a cross-sectional view showing an example of a state after the electric wire with a first terminal 200 and the electric wire with a second terminal 300 are connected.

First, as shown in FIG. 8, a pair of electric wires with terminals 100 including an electric wire 10 of an electric wire with a first terminal 200 and an electric wire 10 of an electric wire with a second terminal 300 are prepared. The axial end face of the conductor 11 in each of the pair of electric wires with terminals 100 is covered with a graphene film 13. Then, the electric wire with first terminal 200 and the electric wire with second terminal 300 are arranged so that the graphene films 13 in each of the pair of electric wires 10 face each other.

Next, as shown in FIG. 9, the electric wire with the first terminal 200 and the electric wire with the second terminal 300 are brought closer to each other in the axial direction to form the electrical connection part 1. Specifically, the graphene films 13 of the pair of electric wires 10 are brought into contact with each other, so that the conductor 11 of the electric wire with the first terminal 200 and the conductor 11 of the electric wire with the second terminal 300 are electrically connected via the graphene film 13. In this way, the electric wire with terminal 100 according to this embodiment can be electrically connected to the mating electric wire 10 by using the graphene film 13 without using metal plating on the electrical contacts.

As described above, the electric wire with terminal 100 according to this embodiment includes an electric wire 10 and a terminal 110. The electric wire 10 includes a conductor 11 and an insulating layer 12 that covers the conductor 11, and the axial end face of the conductor 11 is covered with a graphene film 13. The terminal 110 is provided on the electric wire 10 such that the graphene film 13 on the end face contacts the mating electric wire 10, electrically connecting the electric wire 10 and the mating electric wire 10.

The terminal-equipped electric wire 100 according to this embodiment includes a terminal 110 provided on the electric wire 10 so that the graphene film 13 on the end surface comes into contact with the mating electric wire 10, electrically connecting the electric wire 10 and the mating electric wire 10. This makes it easier to handle the electric wire 10, and by using the graphene film 13, it is possible to electrically connect the electric wire 10 to the mating electric wire 10 without using metal plating on the electrical contacts.

The terminal 110 may also include a pressing portion 223 that applies a force to the wire 10 to push back the mating wire 10 when the wire 10 is pressed axially by the mating wire 10. The pressing portion 223 connects the wire 10 of the first terminal 200 with the wire 10 of the second terminal 300 in a state in which the wire 10 is pressed axially. Even if the second terminal 300 moves away from the first terminal 200, the wire 10 of the first terminal 200 is pressed back and follows the wire 10 of the second terminal 300. Therefore, the electrical connection between the wire 10 of the first terminal 200 and the wire 10 of the second terminal 300 is maintained well.

The terminal 110 may also include an alignment portion 321. The alignment portion 321 surrounds the outer periphery of the electric wire 10 and adjusts the radial position of the mating electric wire 10 relative to the electric wire 10 so that the mating electric wire 10 is electrically connected to the electric wire 10 when the mating electric wire 10 is brought close to the electric wire 10 in the axial direction and brought into contact with the electric wire 10. The alignment portion 321 adjusts the connection position of the electric wire 10 and the mating electric wire 10, so that the electrical connection between the electric wire 10 and the mating electric wire 10 can be made more reliable.

In the above embodiment, an example has been described in which the terminal 210 of the electric wire with the first terminal 200 includes the pressing portion 223, and the terminal 310 of the electric wire with the second terminal 300 includes the alignment portion 321. However, the electric wire with terminal 100 may also include a terminal 110 that includes the pressing portion 223 and the alignment portion 321.

In the above embodiment, the case where the alignment portion 321 includes a cylindrical member having an inner diameter larger than the outer diameter of the electric wire 10 has been described. However, the cylindrical member of the alignment portion 321 may have an inner diameter smaller than the outer diameter of the electric wire 10, and the alignment portion 321 may have a slit in the axial direction. In this way, the alignment portion 321 may be a split sleeve, and a stress such as an elastic force may be generated toward the center of the cylinder. By having the alignment portion 321 have a split sleeve structure, the conductors 11 can be aligned with high precision.

In the above embodiment, an example has been described in which the terminal-equipped electric wire 100 includes one electric wire 10. However, the terminal-equipped electric wire 100 may be a cable in which multiple electric wires 10 are bundled together, instead of a single electric wire 10. An example of a cable in which multiple electric wires 10 are bundled together is a twisted pair cable in which two electric wires are bundled together.

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

REFERENCE SIGNS LIST 1 Electrical connection part 10 Electric wire 11 Conductor 12 Insulating layer 13 Graphene film 100 Electric wire with terminal 200 Electric wire with first terminal 210 Terminal 223 Pressing portion 300 Electric wire with second terminal 310 Terminal 321 Centering portion

Claims (5)

A pair of electric wires including a conductor and an insulating layer covering the conductor,
an end surface of the conductor in each of the pair of electric wires in the axial direction is covered with a graphene film;
the graphene films in the pair of electric wires are in contact with each other,
An electrical connection component , wherein an outer surface of the conductor is covered with the insulating layer along a circumferential direction up to the end face in the axial direction . an electric wire including a conductor and an insulating layer covering the conductor, the axial end face of the conductor being covered with a graphene film;
a terminal provided on the electric wire such that the graphene film on the end surface comes into contact with a mating electric wire to electrically connect the electric wire and the mating electric wire;
Equipped with
An electric wire with a terminal , wherein an outer surface of the conductor is covered with the insulating layer along a circumferential direction up to the end face in the axial direction . The electric wire with terminal according to claim 2 , wherein the terminal includes a pressing portion that imparts to the electric wire a force for pressing back the mating electric wire when the electric wire is pressed in the axial direction by the mating electric wire. 4. The electric wire with terminal according to claim 2 or 3, wherein the terminal includes an alignment portion that surrounds an outer periphery of the electric wire and adjusts a radial position of the mating electric wire with respect to the electric wire so that the mating electric wire is electrically connected to the electric wire when the mating electric wire is brought close to the electric wire in the axial direction and brought into contact with the electric wire. A method for manufacturing an electric wire including a conductor and an insulating layer covering the conductor,
Using an electrophoretic deposition method, coating an axial end face of the conductor with a graphene film ;
A method for manufacturing an electric wire , wherein an outer surface of the conductor is covered with the insulating layer along a circumferential direction up to the end face in the axial direction .

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