JP2016201272A - Noise shield cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise shield cable that has excellent noise inhibition performance and can reduce noise even at a high frequency.SOLUTION: A noise shield cable 1 comprises a conductor wire, an insulator layer provided around the conductor wire, and a noise shield layer that is provided around the insulator layer, and comprises a cladding powder 81 having a magnetic layer 81a and an electric conductor layer 81b mixed with an insulation material.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a noise shielded cable.

  As a method of suppressing noise from the cable, the insulating material contained in the jacket covering the cable core wire is composed of a composite magnetic body made of a flat or needle-like soft magnetic powder and an organic binder, and the soft magnetic powder A method is known in which the surface portion of the metal is an oxidized metal or alloy (see Patent Document 1).

Japanese Patent No. 3712846

  The larger the aspect ratio of the soft magnetic powder, the greater the magnetic permeability of the layer containing the powder, and the higher the magnetic permeability of the layer containing the powder, the better the noise suppression performance, but the increased aspect ratio of the soft magnetic powder. Has mechanical limitations.

  In addition, magnetic materials generally have a high-frequency permeability attenuation known as the limit of Snoek, and therefore cannot cope with higher frequency bands.

  Therefore, an object of the present invention is to provide a noise shielded cable that has excellent noise suppression performance and can reduce noise at high frequencies.

  In order to achieve the above object, the present invention provides the following noise shielded cable.

[1] A conductor wire, an insulator layer provided around the conductor wire, and a clad powder provided around the insulator layer and having a magnetic layer and a conductor layer were mixed with an insulating material. Noise shield cable with a noise shield layer.
[2] The noise shield cable according to [1], wherein the clad powder has a flat shape.
[3] The noise shielded cable according to [2], wherein the flat clad powder has a flat direction (in-plane direction) oriented in a cable longitudinal direction and a circumferential direction.
[4] The noise shield cable according to [2] or [3], wherein a flatness ratio expressed by a maximum length / thickness of the flat clad powder is 2 or more and 90 or less.
[5] The noise shield cable according to any one of [2] to [4], wherein a flatness expressed by a maximum length / thickness of the magnetic layer is 4 or more and 180 or less.
[6] The noise shielded cable according to any one of [1] to [5], wherein the conductor layer attenuates an electromagnetic wave having a frequency higher than a Snoek limit of the magnetic body constituting the magnetic layer. .
[7] The noise shield cable according to any one of [1] to [6], wherein a mixing ratio of the clad powder to the insulating material in the noise shield layer is 5 to 60 vol%.

  ADVANTAGE OF THE INVENTION According to this invention, the noise shield cable which is excellent in noise suppression performance and can also reduce the noise in a high frequency can be provided.

It is a cross-sectional view showing a schematic configuration of a noise shielded cable according to an embodiment of the present invention. It is sectional drawing which shows the structure of the clad powder used with the noise shield cable shown in FIG. (A) And (b) is a perspective view which shows the structure of the clad powder used with the noise shield cable shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a noise shielded cable according to an embodiment of the present invention. 2 is a cross-sectional view showing the configuration of the clad powder used in the noise shielded cable shown in FIG. 1, and FIG. 3 is a perspective view of the same.

  A noise shielded cable 1 shown in FIG. 1 includes a plurality of (three in this embodiment) insulated wires 4 in which the conductor wire 2 is covered with an insulator 3 and inclusions 5 around the plurality of insulated wires 4. Resin tape layer 6 wound in an intervening manner, shield layer 7 provided around resin tape layer 6, noise shield layer 8 provided around shield layer 7, and provided around noise shield layer 8 And a sheath 9 as an insulating protective layer made of a resin or the like. Although not limited to the above configuration, at least one insulator layer is disposed between the conductor wire 2 and the noise shield layer 8.

  The conductor wire 2 is formed by twisting a plurality (seven in this embodiment) of fine metal wires 2a. The insulated wire 4 transmits a signal of 1 MHz to 10 GHz, for example. In addition, although the insulated wire 4 was made into multiple in this Embodiment, one may be sufficient. The insulated wire 4 may be a twisted pair wire that transmits a differential signal.

  The resin tape layer 6 is formed, for example, by winding a resin tape around the plurality of insulated wires 4 with the inclusions 5 interposed therebetween and in the cable longitudinal direction. As the resin tape, for example, a tape made of a resin such as polyethylene terephthalate (PET) or polypropylene resin can be used.

  The shield layer 7 is formed by braiding a conducting wire and connected to the ground. The shield layer 7 may be one in which a tape with a conductor is wound.

  The noise shield layer 8 is a noise shield layer in which a clad powder 81 having a magnetic layer 81a and a conductor layer 81b is mixed with a resin 80 which is an insulating material. The noise shield layer 8 can be formed, for example, by extrusion coating the resin 80 mixed with the clad powder 81. The clad powder 81 is preferably dispersed almost uniformly in the noise shield layer 8 (resin 80).

  The thickness of the noise shield layer 8 is not particularly limited, but is preferably 100 to 1000 μm.

  As the base resin 80, for example, an olefin resin, a vinyl chloride resin, an ethylene-vinyl acetate polymer, a fluorine resin, a silicone resin, or the like can be used. Further, the resin 80 is preferably a crystalline system rather than an amorphous system in order to orient the flat direction when the clad powder 81 has a flat shape in the cable longitudinal direction and the circumferential direction.

  The mixing ratio of the clad powder 81 to the resin 80 is preferably 5 to 60 vol%, and more preferably 10 to 40 vol% in terms of cable flexibility and electromagnetic noise suppression effect.

  The clad powder 81 is a powder obtained by clad the magnetic layer 81a and the conductor layer 81b. For example, the clad powder 81 is laminated with a magnetic sheet and a conductor sheet, clad by rolling or the like, and then formed into a desired shape. It can be obtained by grinding.

  The shape of the clad powder 81 is not particularly limited as long as the magnetic layer 81a and the conductor layer 81b are clad. However, a flat shape is preferable.

  The overall shape of the flat clad powder 81 is not particularly limited, and various shapes can be adopted. For example, a cylindrical shape (disc shape) like the clad powder 81A shown in FIG. A prismatic shape (for example, a quadrangular prism shape) like the clad powder 81B shown in FIG.

  In the flat clad powder 81, the flat direction (in-plane direction) is preferably oriented in the cable longitudinal direction and the circumferential direction. When the clad powder 81 having a substantially disk shape is used, the clad powder 81 mixed with the clad powder 81 is extrusion molded so that the flat direction (in-plane direction) of the clad powder 81 is the cable longitudinal direction (extrusion). Direction) and circumferential direction. That is, the flat surface of the cladding powder 81 is substantially parallel to the cable longitudinal direction and the circumferential direction. Substantially parallel includes the case where the flat plane is inclined at 0 ° or more and 30 ° or less with respect to the cable longitudinal direction and the circumferential direction. The inclination is preferably 20 ° or less, more preferably 10 ° or less, and further preferably 5 ° or less.

  When the flat direction (in-plane direction) of the flat clad powder 81 is oriented in the cable longitudinal direction and the circumferential direction, it is preferable that the magnetic layer 81a is on the sheath 9 side and the conductor layer 81b is on the conductor wire 2 side. .

  The flatness expressed by the maximum length / thickness of the flat clad powder 81 is preferably 2 or more and 90 or less, more preferably 5 or more and 80 or less, and more preferably 10 or more and 70 or less. More preferably, it is 20 or more and 60 or less, and most preferably.

  If the flatness expressed by the maximum length / thickness of the clad powder 81 is less than 2, it is difficult to obtain a desired relative magnetic permeability, and if it exceeds 90, the magnetic layer 81a may be damaged when the noise shield layer 8A is formed. Increases nature. Therefore, the flatness of the clad powder 81 is preferably 2 or more and 90 or less. The size of the cladding powder 81 is preferably 1 μm or more and 20 μm or less in terms of the minimum diameter. Even if all of the clad powder 81 does not satisfy the flattening rate, 80% or more of the clad powder 81 may satisfy the flattening rate, and the remaining flatness may be less than 2.

  The layer thickness ratio between the magnetic layer 81a and the conductor layer 81b is preferably the magnetic layer 81a: the conductor layer 81b = 10: 1 to 1:10, more preferably 5: 1 to 1: 5, and 3: 1 to 1: 3 is more preferable, and 1: 1 is most preferable.

  As the magnetic layer 81a, it is preferable to use a high magnetic permeability material, for example, a magnetic material having a relative magnetic permeability of 1000 to 100,000 and capable of obtaining a noise reduction effect in a low frequency band.

  Specifically, for example, a cobalt-based amorphous ribbon, a tape in which an aluminum foil is laminated on a cobalt-based amorphous ribbon, a resin tape in which magnetic powder is blended, or the like can be used.

  As a material of the magnetic powder blended in the resin tape, a material made of a soft magnetic material is preferable. Examples of soft magnetic materials include ferrite powders such as Mn—Zn ferrite powders, Ni—Zn ferrite powders, Ni—Zn—Cu ferrite powders, Fe—Ni alloys (permalloy), Fe—Si—Al alloys, and the like. Soft magnetic metal powders such as alloys (Sendust) and Fe-Si alloys (silicon steel) can be used. The shape of the magnetic powder is not particularly limited, such as a granular shape (spherical shape), a flat shape, an elliptical shape, a rod shape, or a fiber shape, but a flat shape is preferable. It is preferable that the clad powder 81 has a flat direction substantially the same as the flat direction when the clad powder 81 has a flat shape. As the base resin, for example, an olefin resin, a vinyl chloride resin, an ethylene-vinyl acetate polymer, a fluorine resin, a silicone resin, or the like can be used.

  The flatness represented by the maximum length / thickness of the magnetic layer 81a in the flat clad powder 81 is preferably 4 or more and 180 or less, more preferably 8 or more and 160 or less, and more preferably 20 or more and 140. Or less, and most preferably 40 or more and 120 or less.

  The conductor layer 81b is preferably made of a material that attenuates electromagnetic waves having a frequency higher than the Snoek limit of the magnetic material constituting the magnetic layer 81a. It is preferable to use a high conductivity material, particularly a metal having a high conductivity. For example, copper, gold, silver, and aluminum can be used.

  The sheath 9 is made of, for example, the same resin as the base resin 80 used for the noise shield layer 8. By making the covering layer covering the shield layer 7 into a two-layer structure including the noise shield layer 8 and the sheath 9, the mechanical strength is reinforced. In addition, as a method of covering the outer periphery of the shield layer 7, both the noise shield layer 8 and the sheath 9 may be simultaneously coated by extrusion in consideration of the adhesiveness of the boundary surface between the noise shield layer 8 and the sheath 9. .

  The noise shielded cable according to the embodiment of the present invention can be applied to a communication cable, a LAN cable, a coaxial cable, a power cable, a control / instrumentation cable, and the like.

[Effect of this embodiment]
According to the present embodiment, the following effects can be obtained.
(1) Since the clad powder of the magnetic material layer and the conductive material layer is used, the aspect ratio of the magnetic material layer can be increased even if the overall thickness is the same as that of the magnetic material only. The noise shield cable with improved noise suppression performance can be provided.
(2) Since the clad powder has a conductor layer, it is possible to attenuate an electromagnetic wave having a frequency above the limit of Snoek of the magnetic material, so that it is possible to provide a noise shielded cable that can reduce noise at a high frequency.
(3) Since the aspect ratio of the entire clad powder can be made equal to that of the conventional magnetic powder while increasing the aspect ratio of the magnetic layer as described in (1) above, the level of difficulty in the flattening process (labour) Equivalent to body powder.
(4) Since the conductor layer that is harder to break than the magnetic body is integrated with the magnetic body layer, the conductor layer functions as a base material for preventing cracking of the magnetic body, so that cracking during coating can be prevented.
(5) Since the noise shield layer in which the clad powder having the magnetic layer and the conductor layer is mixed with the insulating material is provided, the shield layer (copper braid or the like) can be omitted.
(6) When flat clad powder is used, the flattening direction is oriented in the longitudinal direction and the circumferential direction of the cable, compared with the case where granular magnetic powder having the same mixing ratio as in this embodiment is used. Since the impedance increases, it is possible to increase the effect of suppressing electromagnetic noise (radiation noise) radiated from the cable.
(7) When flat clad powder is used, orienting the flat direction in the longitudinal direction and circumferential direction of the cable to obtain the same electromagnetic wave noise suppression effect as compared with the case of using granular magnetic powder This makes it possible to reduce the amount of magnetic powder.
(8) Since it is not necessary to use a ferrite core, it is aesthetically pleasing, there is no problem in handling such as cracking of the ferrite core, and the emission of electromagnetic noise can be suppressed without increasing the outer diameter of the cable.

  The embodiments of the present invention are not limited to the above-described embodiments, and various embodiments are possible.

  Further, it is possible to omit or change some of the constituent elements of the above-described embodiment within a range not changing the gist of the present invention. For example, the inclusion 5 may be omitted if there is no problem in winding the resin tape around the plurality of insulated wires 4.

1: noise shield cable 2: conductor wire, 2a: fine metal wire, 3: insulator, 4: insulated wire, 5: inclusion 6: resin tape layer, 7: shield layer, 8: noise shield layer, 9: sheath 80 : Resin, 81, 81A, 81B: clad powder 81a: magnetic layer, 81b: conductor layer

Claims (7)

  A noise shield layer comprising a conductor wire, an insulator layer provided around the conductor wire, and a clad powder provided around the insulator layer and having a magnetic layer and a conductor layer mixed with an insulating material Noise shielded cable with   The noise shielded cable according to claim 1, wherein the clad powder has a flat shape.   The noise shield cable according to claim 2, wherein the flat clad powder has a flat direction (in-plane direction) oriented in a cable longitudinal direction and a circumferential direction.   4. The noise shielded cable according to claim 2, wherein a flatness ratio expressed by a maximum length / thickness of the flat clad powder is 2 or more and 90 or less. 5.   The noise shielding cable according to any one of claims 2 to 4, wherein the flatness expressed by the maximum length / thickness of the magnetic layer is 4 or more and 180 or less.   The noise shield cable according to any one of claims 1 to 5, wherein the conductor layer attenuates electromagnetic waves having a frequency higher than a Snoek limit of a magnetic material constituting the magnetic layer. The noise shield cable according to any one of claims 1 to 6, wherein a mixing ratio of the clad powder to the insulating material in the noise shield layer is 5 to 60 vol%.

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