JP7395341B2 - Shield members and shield wires - Google Patents

Description

The present invention relates to a shield member and a shielded wire.

2. Description of the Related Art Conventionally, a metal braid formed into a cylindrical shape by braiding metal wires, for example, has been known. Such a metal braid is used as a shielded wire by inserting an electric wire or the like into the tube (see, for example, Patent Document 1). Further, the braid may be formed of plated fibers in which the fibers are plated with metal.

JP 2015-69733 Publication

Here, regarding the braid described in Patent Document 1, there is a demand to reduce the number of metal members, and a part of the braid may be formed of non-metallic fibers as long as the shielding effect is not extremely reduced. . This is because, while exhibiting a shielding effect, the amount of metal material can be reduced and costs can be held down.

Here, for the above-mentioned braid, the shielding effect in the low frequency range tends to be dominated by the conductor resistance (resistance of the metal wire or plated fiber). Therefore, it is preferable that the conductor resistance is low, but since metal wires and the like are woven into the braid, the length of the metal wires and the like in the braid at a predetermined distance is longer than the predetermined distance. Therefore, the resistance value increases and the shielding effect in the low frequency range decreases.

Therefore, it is possible to consider a shielding member that is aligned in the same direction as the electric wires to be shielded without weaving metal wires, etc., but it is difficult to maintain the shape due to gaps between the aligned metal wires, etc. This will lead to a decrease in effectiveness.

The present invention has been made to solve these conventional problems, and its purpose is to reduce the number of metal members, reduce the shielding effect due to deformation, and improve the shielding effect in the low frequency range. An object of the present invention is to provide a shield member and a shielded electric wire that can suppress a decrease in .

The shield member according to the present invention includes a cylindrical portion formed into a cylindrical shape by weaving a plurality of non-metallic fibers, and a conductor wire that is at least one of a metal wire or a plated fiber in which the fiber is metal-plated. an alignment part formed by knitting the cylindrical part in the cylinder axis direction of the cylindrical part, and the surface area of the cylindrical part and the alignment part on the outside of the cylinder is The surface area of the alignment portion inside and outside the cylinder is 80% or more and 90% or less.

According to the present invention, since the cylindrical portion is formed into a cylindrical shape by weaving a plurality of non-metallic fibers, the number of metal members can be reduced. In addition, compared to a shielding member in which metal wires, etc. are simply drawn in the same direction as the electric wires to be shielded, there are no gaps in the metal wires, etc., and the shielding effect is prevented from deteriorating due to deformation. I can do it. In addition, the surface area of the alignment part inside and outside the cylinder is set to be 62% or more and 90% or less of the surface area of the cylindrical part and the alignment part on the outside of the cylinder. Therefore, more than a certain amount of conductor wire is arranged along the cylinder axis, and the length of the conductor wire is difficult to increase relative to the length of the shield member, suppressing the increase in resistance value and improving the shielding effect in the low frequency range. It is also possible to suppress the decline. Therefore, while reducing the number of metal members, it is possible to suppress deterioration of shielding effectiveness due to deformation and deterioration of shielding effectiveness in a low frequency range.

FIG. 1 is a perspective view showing the configuration of a shielded wire according to an embodiment of the present invention. 2 is a partially enlarged plan view of the shield member shown in FIG. 1. FIG. It is a graph showing the measurement results of shielding effects according to Examples and Comparative Examples.

Hereinafter, the present invention will be explained along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be modified as appropriate without departing from the spirit of the present invention. In addition, in the embodiments described below, illustrations and explanations of some components are omitted, but the details of the omitted techniques will be described within the scope of not contradicting the content described below. It goes without saying that publicly known or well-known techniques are applied as appropriate.

FIG. 1 is a perspective view showing the configuration of a shielded wire according to an embodiment of the present invention. As shown in FIG. 1, a shielded wire 1 according to the present embodiment protects an internal wire 20 from noise arriving from the outside, and includes a shield member 10 and a wire arranged inside the shield member 10. The electric wire 20 is provided. In FIG. 1, the electric wire 20 includes an insulated electric wire 21 and a drain wire 22.

The insulated wire 21 is connected to a predetermined target to transmit power, signals, etc., and includes a conductor 21a and an insulator 21b. The conductor 21a is made of, for example, an annealed copper wire, a copper alloy wire, a tin-plated annealed copper wire, a tin-plated copper alloy wire, a silver-plated annealed copper wire, a silver-plated copper alloy wire, or the like. The insulator 21b is provided around the outer periphery of the conductor 21a, and is made of, for example, PE (Polyethylene), PP (Polypropylene), PTFE (Polytetrafluoroethylene), foamed PE, PP, PTFE, or the like. .

The end of the drain wire 22 is connected to a ground point in order to ground the noise blocked by the shield member 10. This drain wire 22 is a bare wire without an insulator 21b, and is electrically connected to the shield member 10. Similarly to the conductor 21a of the insulated wire 21, the drain wire 22 is made of, for example, an annealed copper wire, a copper alloy wire, a tin-plated annealed copper wire, a tin-plated copper alloy wire, a silver-plated annealed copper wire, a silver-plated copper alloy wire, etc. There is.

In addition, although the conductor 21a of the insulated wire 21 and the drain wire 22 are assumed to be a single wire in FIG. 1, the present invention is not limited to this, and may be a stranded wire in which a plurality of wires are twisted.

FIG. 2 is a partially enlarged plan view of the shield member 10 shown in FIG. The shield member 10 shown in FIGS. 1 and 2 includes a cylindrical portion 11 and an alignment portion 12. The shield member 10 shown in FIGS.

The cylindrical portion 11 is formed into a cylindrical shape by weaving a plurality of non-metallic fibers. In this embodiment, the non-metallic fiber is, for example, a polyarylate fiber (an example of a tensile strength fiber having a tensile strength at break of 1 GPa or more and an elongation rate at break of 1% or more and 10% or less). Note that the non-metallic fibers are not limited to these, and other tensile strength fibers such as aramid fibers and PBO fibers may be employed, and not only tensile strength fibers but also other fibers (for example, carbon fibers) may be employed. may have been done.

The aligned portion 12 is formed by weaving a conductor wire into the cylindrical portion 11 in the axial direction of the cylindrical portion 11 . In this embodiment, the conductor wire is made of a polyarylate fiber plated with copper. Note that the conductor wire is not limited to this, and may be a metal wire such as copper or tin. Furthermore, the plated fibers are not limited to polyarylate fibers with metal plating, but may be other fibers (for example, other tensile strength fibers) with metal plating. Further, the metal plating is not limited to copper plating, and may be plating made of other metals such as tin.

The aligned portion 12 may be formed by weaving the conductor wire after the cylindrical portion 11 is formed, or may be formed by weaving the conductor wire together with the formation of the cylindrical portion 11. In particular, when knitting the conductor wire together with the formation of the cylindrical part 11, the non-metallic fibers forming the cylindrical part 11 are wound on a movable bobbin, and the conductor wire is wound on a bobbin that does not move in the weaving direction. I'll keep it. By pulling out and weaving the fibers and conductor wires wound around these bobbins, it is possible to form the cylindrical portion 11 and to weave the conductor wires extending in the direction of the cylinder axis.

As described above, the shield member 10 according to the present embodiment has a structure in which the number of metal members is reduced because the cylindrical portion 11 is made of non-metallic fibers as described above. In addition, since the alignment portion 12 is woven in the direction of the cylinder axis of the cylindrical portion 11, there is no gap between the metal wires, etc., compared to a shield member in which metal wires, etc. are simply aligned. The structure prevents the shielding effect from deteriorating due to deformation.

Furthermore, in this embodiment, the surface area of the cylindrical part 11 and the alignment part 12 on the outside of the cylinder (the surface area of the shield member 10) is 62% or more and 90% or less of the surface area of the alignment part 12 inside and outside the cylinder. has been done.

By adopting such a configuration, the shield member 10 according to the present embodiment has a certain amount or more of conductor wires arranged along the cylinder axis, and the length of the conductor wires is smaller than the length of the shield member 10. It does not easily become long, suppresses an increase in resistance value, and suppresses a decrease in shielding effectiveness in a low frequency range.

Next, examples and comparative examples according to the present invention will be described. FIG. 3 is a graph showing measurement results of shielding effects according to Examples and Comparative Examples.

First, for Example 1, a cylindrical part was formed using 48 strands of polyarylate fibers, and 12 copper-plated polyarylate fibers were woven together with the cylindrical part and aligned in the axial direction of the cylinder to form a shield member. Formed. As a result, the surface area of the alignment portion inside and outside the cylinder was 90% of the surface area of the shield member. Note that the copper-plated polyarylate fiber had a resistance value of 1 Ω/m.

Further, in Example 2, ten copper-plated polyarylate fibers were used, and the surface area was set to 62%. The other configurations are the same as in the first embodiment.

In addition, in Comparative Example 1, eight copper-plated polyarylate fibers were used, and the surface area was set to 47%. The other configurations are the same as in the first embodiment.

Furthermore, in Comparative Example 2, a braid was formed using non-metallic fibers and conductor wires in which each wire was inclined at 30 degrees in the direction of the cylinder axis. As for the non-metallic fibers, PET (Polyethylene Terephthalate) fibers were used. As for the conductor wire, the same copper-plated polyarylate fiber as in Example 1 was used. Regarding the braid (shield member) formed by weaving both, the surface area of the conductor wire inside and outside the cylinder was 69% of the surface area of the shield member.

In Examples 1 and 2, the shielding effect exceeded both Comparative Examples 1 and 2 in the low frequency range (10 kHz or more and 500 kHz or less).

Further, in Comparative Example 1, the shielding effect did not exceed 50 dB in the low frequency region, and was lower than that in Comparative Example 2 in most of the low frequency region. As a result, it was found that when the surface area of the aligned portion was less than 62%, the shielding effect may be lower than that of Comparative Example 2.

Therefore, it has been found that the surface area of the alignment portion inside and outside the cylinder is preferably 62% or more and 90% or less with respect to the surface area of the shield member.

Note that in Example 1, in which the surface area of the alignment portion inside and outside the cylinder was 90% of the surface area of the shield member, the shielding effect exceeded both Comparative Examples 1 and 2 even in the high frequency range. Although not shown, it was found that when the surface area is 80% or more and 90% or less, the shielding effect exceeds both Comparative Examples 1 and 2 even in the high frequency range (5 MHz to 400 MHz).

In this manner, the shield member 10 according to the present embodiment includes the cylindrical portion 11 formed into a cylindrical shape by weaving a plurality of non-metallic fibers, so that the number of metal members can be reduced. In addition, compared to a shielding member in which metal wires, etc. are simply drawn in the same direction as the electric wire 20 to be shielded, there is no gap between the metal wires, etc., and a reduction in the shielding effect due to deformation is prevented. be able to. In addition, the surface area of the alignment part 12 inside and outside the cylinder is set to be 62% or more and 90% or less of the surface area of the cylindrical part 11 and the alignment part 12 on the outside of the cylinder. Therefore, a certain amount or more of the conductor wire is arranged along the cylinder axis, and the length of the conductor wire is difficult to increase with respect to the length of the shield member 10, suppressing the increase in resistance value and improving the shielding effect in the low frequency range. It is also possible to suppress the decrease in Therefore, while reducing the number of metal members, it is possible to suppress deterioration of shielding effectiveness due to deformation and deterioration of shielding effectiveness in a low frequency range.

Furthermore, since the shielded wire 1 according to the present embodiment includes the shield member 10 and the wire 20 disposed inside the shield member 10, the shielding effect may be reduced due to deformation while reducing the number of metal members. Furthermore, it is possible to provide the shielded wire 1 that suppresses deterioration of the shielding effect in the low frequency range.

Although the present invention has been described above based on the embodiments, the present invention is not limited to the above embodiments, and changes may be made without departing from the spirit of the present invention, and well-known and publicly known techniques may be used. May be combined.

For example, in the above embodiment, the alignment part 12 is woven into the cylindrical part 11 and extends in the axial direction of the cylinder, but the axial direction and the cylindrical axis do not need to be completely aligned; It may be inclined by a certain degree (for example, 5° or less) with respect to the cylinder axis. This is because the same effect can be obtained also by this.

1: Shielded wire 10: Shield member 11: Cylindrical portion 12: Aligned portion 20: Electric wire 21: Insulated wire 21a: Conductor 21b: Insulator 22: Drain wire

Claims (2)

A cylindrical part formed into a cylindrical shape by weaving multiple non-metallic fibers;
an aligned portion formed by weaving at least one conductor wire of a metal wire or a plated fiber in which metal plating is applied to the cylindrical portion in the axial direction of the cylindrical portion;
A shield member characterized in that a surface area of the alignment part inside and outside the cylinder is 80% or more and 90% or less of a surface area of the cylindrical part and the alignment part on the outside of the cylinder. The shield member according to claim 1;
an electric wire arranged inside the shield member;
A shielded wire characterized by comprising:

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