2-core parallel shielded electric wire

Abstract

To provide a two core parallel shield electric wire capable of improving terminal processability while maintaining adhesion between two insulation electric wires and metal foil.SOLUTION: A two core parallel shield electric wire 1 includes: two insulated electric wires 10 disposed in parallel; a metal foil 20 vertically attached around the two insulated electric wires 10; a resin film 30 having a thickness of 25 μm or less wound in a state of having spacing S of 0.5 mm or more in a longitudinal direction on the metal foil 20; a shield braid 40 which can be electrically continuous with the metal foil 20, and which is formed by braiding a conductive wire and covers over the metal foil 20 and the resin film 30; and an insulator 50 disposed in contact with the shield braid 40 on the shield braid 40.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a two-core parallel shielded wire.

Background Art

[0002] Conventionally, for example, a two-core parallel shielded wire has been proposed in which two insulated wires are arranged in parallel, a drain wire such as a bare wire is provided along the two insulated wires, a metal foil is vertically attached around them, and a resin tape is wound on the metal foil (see, for example, Patent Document 1). Such a two-core parallel shielded wire is configured to suppress rapid signal attenuation (sackout) in the high-frequency region by vertically attaching a metal foil.

[0003] In addition, in the above two-core parallel shielded wire, since the metal foil is vertically attached to the two insulated wires, the adhesion between the two insulated wires and the metal foil is not high, and ultimately, sackout may occur or the communication characteristics may become unstable. However, in the two-core parallel shielded wire described in Patent Document 1, since the resin tape is wound on the metal foil, the adhesion between the two insulated wires and the metal foil is ensured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For the purpose of improving the bending resistance and the like, the inventors of the present application have considered a two-core parallel shielded wire in which a braided shield formed by braiding a metal wire or the like is covered on the one described in Patent Document 1, and an insulator is coated on the braided shield by extrusion molding or the like. However, for this two-core parallel shielded wire, it is necessary to perform terminal processing on both the drain wire and the shield braid, and the terminal processability is not good at all.

[0006] The present invention has been made to solve such conventional problems, and an object thereof is to provide a two-core parallel shielded wire capable of improving terminal processability while ensuring the adhesion between two insulated wires and a metal foil.

Means for Solving the Problems

[0007] The two-core parallel shielded wire of the present invention is a two-core parallel shielded wire including two insulated wires arranged in parallel and a metal foil longitudinally attached around the two insulated wires, wherein a resin film with a thickness of 25 μm or less wound around the metal foil with a gap of 0.5 mm or more in the longitudinal direction, a shield braid formed by braiding conductive wires, covering the metal foil and the resin film, and being electrically conductive with the metal foil, and an insulator provided in contact with the shield braid on the shield braid.

Effects of the Invention

[0008] According to the two-core parallel shielded wire according to the present invention, it is possible to improve terminal processability while ensuring the adhesion between two insulated wires and a metal foil.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described along preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be appropriately changed without departing from the gist of the present invention. Also, in the embodiments shown below, there are some places where the illustration and description of some configurations are omitted. However, it goes without saying that well-known or well-understood technologies are appropriately applied within the range that does not conflict with the content described below regarding the details of the omitted technologies.

[0011] FIG. 1 is a top view showing the wiring structure of a two-core parallel shielded wire according to an embodiment of the present invention. As shown in FIG. 1, the two-core parallel shielded wire 1 electrically connects, for example, a first device M1 and a second device M2 mounted in a vehicle.

[0012] The first device M1 and the second device M2 are devices that transmit and receive high-frequency signals, for example, in the range of 200 MHz or more and 26.5 GHz or less. The two-core parallel shielded wire 1 is wired between such first device M1 and second device M2. The first device M1 and the second device M2 transmit signals having opposite phases to each other with respect to two insulated wires (refer to reference numeral 10 in FIG. 2) described later. The receiving side synthesizes and outputs the difference of each received signal.

[0013] FIG. 2 is a perspective view showing the two-core parallel shielded wire 1 shown in FIG. 1. As shown in FIG. 2, the two-core parallel shielded wire 1 includes two insulated wires 10, a metal foil 20, a resin film 30, a shield braid 40, and an insulator 50.

[0014] The two insulated wires 10 are arranged side by side and parallel to each other, and each is composed of a conductor 11 coated with an insulator 12. The conductor 11 is composed of a conductive metal such as a soft copper wire, a copper alloy wire, a tinned soft copper wire, a tinned copper alloy wire, a silver-plated soft copper wire, and a silver-plated copper alloy wire. The insulator 12 is composed of PE (Polyethylene), PP (Polypropylene), or PTFE (Polytetrafluoroethylene), or foamed PE, PP, or PTFE.

[0015] In addition, in the example shown in FIG. 2, the conductor 11 is composed of a single wire, but it is not limited to a single wire and may be composed of a stranded wire made of a plurality of strands or the like. Further, each strand may be one having a metal plating on a tensile strength fiber. The tensile strength fiber is a fiber material chemically synthesized from a raw material such as petroleum, and has a tensile strength at break of 1 GPa or more and an elongation at break of 1% or more and 10% or less. Examples of the tensile strength fiber include fibers such as aramid fiber, polyarylate fiber, and PBO fiber. A metal foil 20 is provided on the two insulated wires 10 having such a conductor 11.

[0016] The metal foil 20 is formed by forming a metal such as aluminum or copper on a flexible foil and is vertically attached to the two insulated wires 10. The metal foil 20 may be composed only of a metal, or may be a resin tape with a metal thin film adhered thereto or a resin tape with a metal vapor-deposited thereon. When the metal foil 20 is formed of a resin tape, it is arranged such that the metal surface faces outward.

[0017] Here, as shown in FIG. 2, the two-core parallel shielded wire 1 according to the present embodiment is configured not to include a drain wire. The drain wire is, for example, a bare wire arranged along the two insulated wires 10 and is brought into contact with the metal foil 20 to be electrically connected. As will be described later, in the two-core parallel shielded wire 1 according to the present embodiment, since the shield braid 40 is in contact with the metal foil 20 to be in a conductive state, terminal processing (ground connection) may be performed on the shield braid 40, and the drain wire is unnecessary.

[0018] The resin film 30 is wound around the metal foil 20 with a gap S in the longitudinal direction. This resin film 30 is composed of, for example, a PET (Polyethylene Terephthalate) foil.

[0019] The shield braid 40 is formed by braiding conductive wires and covers the metal foil 20 and the resin film 30. Here, the conductive wires constituting the shield braid 40 are composed of, similar to the conductor 11, soft copper wires, copper alloy wires, tin-plated soft copper wires, tin-plated copper alloy wires, silver-plated soft copper wires, silver-plated copper alloy wires, and the like. Further, the conductive wires are not limited to these, and may be those obtained by applying metal plating to tensile strength fibers, carbon fibers, or the like.

[0020] The insulator 50 is provided on the shield braid 40 and is composed of PE, PP, or PTFE, or foamed PE, PP, or PTFE, similar to the insulator 12 of the insulated wire 10. In particular, in this embodiment, since the insulator 50 is extrusion-molded or the like and is provided in pressing contact on the shield braid 40, it exerts an action of pressing the shield braid 40 toward the metal foil 20 side.

[0021] Here, in this embodiment, the gap S in the longitudinal direction of the resin film 30 is set to 0.5 mm or more, and the thickness of the resin film 30 is set to 25 μm or less. For this reason, the shield braid 40 is brought into contact conduction with the metal foil 20 through the gap S of the resin film 30. That is, since the gap S is 0.5 mm or more, a sufficient interval is provided for the shield braid 40 to enter, and since the thickness of the resin film 30 is 25 μm or less, a situation where it becomes too thick and the shield braid 40 cannot reach the metal foil 20 does not occur. As a result of the above, the shield braid 40 is brought into contact conduction with the metal foil 20 through the gap S of the resin film 30.

[0022] In addition, since the resin film 30 is wound around the metal foil 20, the metal foil 20 comes into close contact with the two insulated electric wires 10, and the communication characteristics can be stabilized.

[0023] Here, in the present embodiment, the width of the resin film 30 is 1 mm or more and 5 mm or less, the winding pitch is 2.5 mm or more and 10.5 mm or less, and it is preferable that the resin film 30 is wound on the metal foil 20 with a longitudinal gap S of 0.5 mm or more and 9.0 mm or less.

[0024] This is because it is possible to prevent a situation where it becomes difficult to bring the metal foil 20 into close contact with the two insulated electric wires 10 due to the width of the resin film 30 being less than 1 mm, and it is also possible to prevent a situation where the gap S becomes extremely small due to the width of the resin film 30 exceeding 5 mm. Furthermore, since the winding pitch is 2.5 mm or more and 10.5 mm or less, it is possible to prevent a situation where it becomes difficult to secure the gap S due to the winding pitch being less than 2.5 mm, and it is also possible to prevent a situation where it becomes difficult to bring the metal foil 20 into close contact with the two insulated electric wires 10 due to the winding pitch exceeding 10.5 mm. Moreover, by setting the gap S to be not only 0.5 mm or more but also 9.0 mm or less, it is possible to prevent a situation where it becomes difficult to bring the metal foil into close contact with the two insulated electric wires 10 by the resin film 30.

[0025] For the two-core parallel shielded electric wire 1 as described above, the resin film 30 can ensure the adhesion of the metal foil 20 to the two insulated electric wires 10, and since the shield braid 40 is electrically connected to the metal foil 20, only the shield braid 40 needs to be subjected to terminal processing, and the terminal processability can be improved.

[0026] FIG. 3 and FIG. 4 are conceptual diagrams showing the winding pitch and the gap S. As shown in FIGS. 3 and 4, the resin film 30 is not limited to one (see FIG. 3), and two resin films 31 and 32 may be wound so as to cross each other (see FIG. 4).

[0027] First, as shown in FIG. 3, when one resin film 30 is wound, both the gap S and the winding pitch P are basically substantially constant. However, as shown in FIG. 4, when two resin films 31 and 32 are wound so as to cross each other, the gap S has different values depending on the location in the width direction.

[0028] Specifically, in the portion C1 where the two resin films 30 completely cross each other in the width direction (the portion where the other resin film 32 is hidden by one resin film 31), the longitudinal gap S1 shows the maximum value. Also, in the portion C2 where the two resin films 30 do not cross each other in the width direction (the portion where one resin film 31 does not hide a part of the other resin film 32), the longitudinal gap S2 shows the minimum value. Note that the gap S2 showing the minimum value is the total value of the two gaps S2a and S2b divided by the resin films 31 and 32.

[0029] In such a case, if the gap S1, which is the maximum value, is 0.5 mm or more, conduction between the shield braid 40 and the metal foil 20 can be achieved at that location. Also, if the gap S2, which is the minimum value, is 9.0 mm or less, the metal foil 20 can be suitably adhered to the two insulated wires 10 by the resin film 30.

[0030] Furthermore, the winding pitches P1 and P2 of the two resin films 31 and 32 may be different from each other. In this case, the smaller winding pitch may be 2.5 mm or more and 10.5 mm or less. For example, if the smaller winding pitch is 2.5 mm or more, since the other winding pitch is larger than that, it is possible to prevent a situation where both winding pitches become less than 2.5 mm and it becomes difficult to secure the gap S. Also, if the smaller winding pitch is 10.5 mm or less, it is easy to adhere the metal foil 20 to the two insulated wires 10 by the smaller winding pitch, and there is no problem even if there is a resin film 30 with a larger winding pitch.

[0031] Next, the characteristics of the two-core parallel shielded wire 1 according to this embodiment will be described. FIGS. 5 and 6 are graphs showing shield characteristics. FIG. 5 shows the characteristics when the resin film 30 is wound with the gap S being 9 mm or less, and FIG. 6 shows the characteristics when the resin film 30 is not wound.

[0032] As shown in FIGS. 5 and 6, when the resin film 30 is not wound, the variation in the attenuation amount is larger compared to the case where the resin film 30 is wound so that the gap S is 9 mm or less. That is, when the resin film 30 is not wound, it can be seen that the adhesion between the metal foil 20 and the two insulated wires 10 cannot be ensured, and the shield characteristics are unstable.

[0033] On the other hand, when the resin film 30 is wound so that the gap S is 9 mm or less, it can be seen that the shield characteristics are stable because the adhesion between the metal foil 20 and the two insulated wires 10 can be ensured.

[0034] FIG. 7 is a graph comparing a representative example of the characteristics when the resin film 30 is wound so that the gap S is 0.5 mm or more and 9 mm or less, and a representative example of the characteristics when the resin film 30 is wound so that the gap S exceeds 9 mm. In FIG. 7, the characteristics when the resin film 30 is wound so that the gap S is 0.5 mm or more and 9 mm or less are shown by a solid line, and the characteristics when the resin film 30 is wound so that the gap S exceeds 9 mm are shown by a broken line.

[0035] As shown in FIG. 7, when the resin film 30 is wound so that the gap S is 0.5 mm or more and 9 mm or less, not only can the adhesion between the metal foil 20 and the two insulated wires 10 be ensured, but also the electrical continuity between the shield braid 40 and the metal foil 20 is ensured. As a result, the shielding effect is preferably exhibited.

[0036] On the other hand, when the resin film 30 is wound so that the gap S is less than 0.5 mm, although the adhesion between the metal foil 20 and the two insulated wires 10 can be ensured, the conductivity between the shield braid 40 and the metal foil 20 becomes unstable. As a result, for example, when communicating between the first device M1 and the second device M2 shown in FIG. 1, noise is likely to leak to the outside and the shielding performance becomes unstable.

[0037] Thus, according to the two-core parallel shielded wire 1 according to the present embodiment, the resin film 30 has a thickness of 25 μm or less and is wound on the metal foil 20 with a gap S of 0.5 mm or more in the longitudinal direction. The resin film 30 is covered with the shield braid 40, and the insulator 50 is further provided thereon. Therefore, the shield braid 40 can be electrically connected to the metal foil 20 through the gap S. As a result, it is not necessary to perform terminal processing on both the shield braid 40 side and the metal foil 20 side. For example, only the shield braid 40 needs to be subjected to terminal processing. In addition, since the resin film 30 is wound, the metal foil 20 is pressed toward the two insulated wires 10, and the adhesion between the two insulated wires 10 and the metal foil 20 is also ensured. Therefore, it is possible to improve the terminal processability while ensuring the adhesion between the two insulated wires 10 and the metal foil 20.

[0038] In addition, since the width of the resin film 30 is 1 mm or more and 5 mm or less, it is possible to prevent a situation where the width of the resin film 30 becomes less than 1 mm and it becomes difficult to bring the metal foil 20 into close contact with the two insulated wires 10, and it is possible to prevent a situation where the width of the resin film 30 exceeds 5 mm and the gap becomes extremely small. Further, since the winding pitch P is 2.5 mm or more and 10.5 mm or less, it is possible to prevent a situation where the winding pitch P becomes less than 2.5 mm and it becomes difficult to secure the above-described gap, and it is possible to prevent a situation where the winding pitch P exceeds 10.5 mm and it becomes difficult to bring the metal foil 20 into close contact with the two insulated wires 10 by the resin film 30. Furthermore, by setting the gap S to be not only 0.5 mm or more but also 9.0 mm or less, it is possible to prevent a situation where it becomes difficult to bring the metal foil 20 into close contact with the two insulated wires 10 by the resin film 30. From the above, it is possible to provide the two-core parallel shielded wire 1 that more suitably secures the adhesion between the two insulated wires 10 and the metal foil 20 while improving the terminal processability.

[0039] As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments, and modifications may be made without departing from the spirit of the present invention, or known and publicly known techniques may be combined.

[0040] For example, in the above-described embodiment, the two-core parallel shielded wire 1 does not require a drain wire, but is not limited thereto, and a drain wire may be provided. Needless to say, in this case, it is not necessary to perform terminal processing on the drain wire.

Explanation of Reference Numerals

[0041] 1: Two-core parallel shielded wire 10: Insulated wire 20: Metal foil 30, 31, 32: Resin film 40: Shield braid 50: Insulator P, P1, P2: Winding pitch S, S1, S2, S2a, S2b: Gap

Claims

1. A two-core parallel shielded wire comprising two insulated wires arranged in parallel and a metal foil longitudinally attached around the two insulated wires, two resin films with a thickness of 25 μm or less wound around the metal foil with a gap in the longitudinal direction, a shield braid formed by braiding conductive wires, covering the metal foil and the resin films, and electrically conductive with the metal foil, and an insulator provided in contact with the shield braid on the shield braid. The two resin films are wound so that their winding directions are opposite to each other and cross each other, and the maximum value of the gap in the longitudinal direction is 0.5 mm or more and the minimum value is 9.0 mm or less. A two-core parallel shielded wire characterized by the above.

2. A two-core parallel shielded wire comprising two insulated wires arranged in parallel and a one-layer metal foil longitudinally attached around the two insulated wires, a resin film with a thickness of 25 μm or less wound around the metal foil with a gap of 0.5 mm or more in the longitudinal direction, a shield braid formed by braiding conductive wires, covering the metal foil and the resin film, and electrically conductive with the metal foil, and an insulator provided in contact with the shield braid on the shield braid. A two-core parallel shielded wire characterized by the above.

3. A two-core parallel shielded wire comprising two insulated wires arranged in parallel and a metal foil longitudinally attached around the two insulated wires, a resin film with a thickness of 25 μm or less wound around the metal foil with a gap of 0.5 mm or more in the longitudinal direction, a shield braid formed by braiding conductive wires, covering the metal foil and the resin film, and electrically conductive with the metal foil, and an insulator provided in contact with the shield braid on the shield braid. The two insulated electric wires are such that the conductor is composed of a plurality of strands, and each strand is obtained by applying a metal plating to a tensile fiber having a tensile strength of 1 GPa or more and an elongation at break of 1% or more and 10% or less at the time of break. A two-core parallel shielded electric wire characterized by this.

4. A two-core parallel shielded electric wire including two insulated electric wires arranged in parallel and a metal foil longitudinally attached around the two insulated electric wires, A resin film with a thickness of 25 μm or less wound around the metal foil with a gap of 0.5 mm or more in the longitudinal direction, A shield braid formed by braiding conductive wires, covering the metal foil and the resin film, and being electrically conductive with the metal foil, An insulator provided in contact with the shield braid on the shield braid, The conductive wire of the shield braid is obtained by applying a metal plating to a tensile fiber having a tensile strength of 1 GPa or more and an elongation at break of 1% or more and 10% or less at the time of break, or is a carbon fiber. A two-core parallel shielded electric wire characterized by this.

Images