JP5331310B2 - Electromagnetic shielding cable - Google Patents

Description

  The present invention relates to an electromagnetic shielding cable having an electromagnetic shielding layer made of a braid.

  As a technique of an electromagnetic shielding cable having an electromagnetic shielding layer composed of a braid, for example, it is disclosed in Patent Document 1 below. Hereinafter, the electromagnetic shielding cable disclosed in the following Patent Document 1 will be described with reference to FIG.

  In FIG. 3A, the electromagnetic shielding cable 1 includes a cable core 2, an electromagnetic shielding layer 3 provided on the cable core 2, and a sheath 4 covered on the electromagnetic shielding layer 3. Has been. In FIG. 3B, the electromagnetic shielding layer 3 is manufactured by simultaneously knitting (knitting) a bundle 5 of conductive metal strands and a bundle 6 of soft magnetic metal strands. In the case of FIG. 3B, the bundle 5 of conductive metal strands is formed by arranging four strands (the number is 4). Similarly, the bundle 6 of soft magnetic metal wires is formed by arranging four wires (the number is 4). Note that the four strands are actually arranged in such a way that the neighbors are in contact with each other without a gap as shown in FIG.

  The bundle of metal wires (5, 6) is called a pick p. Since the electromagnetic shielding layer 3 is provided so as to wind around the cable core 2 as shown in FIG. 3A, a plurality of picks p are present in the circumferential direction of the cable core 2. . Regarding the electromagnetic shielding layer 3, the number of picks in the circumferential direction is called a hit number.

When viewed in the circumferential direction, the electromagnetic shielding layer 3 is manufactured such that the braiding density as a ratio of the surface area of the metal strand covering and occupying the surface of the cable core 2 is 95% or more (braiding Density: Ratio of the surface area of the metal wire occupying the surface of the cable core 2 to the surface area of the cable core 2). Since the electromagnetic shielding layer 3 has a structure having a stitch 7 as shown in FIG. 3B, the electromagnetic shielding layer 3 is manufactured by devising a knitting method or the like so that the opening area of the stitch 7 is minimized. The electromagnetic shielding layer 3 covers the surface of the cable core 2 by 95% or more as a whole to shield the electromagnetic wave.
JP 2006-331758 A

  By the way, in the electromagnetic shielding layer 3 of the above prior art, as can be seen from this knitting method, when viewed in the circumferential direction of the cable core 2, a bundle 5 of conductive metal wires and a soft magnetic metal element are used. It is manufactured in such a state that the bundle of wires 6 becomes a half ratio. Therefore, even if the braiding density of the electromagnetic shielding layer 3 is 95% or more as a whole, the braiding density of only the portion formed by the bundle 6 of soft magnetic metal wires that is effective for the electromagnetic shielding effect is 47.5. %. That is, it cannot be said that the high electromagnetic shielding effect is obtained.

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to provide the electromagnetic shielding cable from which the high electromagnetic shielding effect is acquired.

The electromagnetic shielding cable of the present invention according to claim 1 made to solve the above problems is a braid composed of a conductive metal strand and a soft magnetic metal strand, and covers the surface of the cable core. In the electromagnetic shielding cable having an electromagnetic shielding layer in which the braid density as a whole of the occupied braid is 95% or more in the circumferential direction of the cable core, the braid includes the pick of the conductive metal wire and the soft magnetic wire. It consists of a braid of metal wire picks,
The electromagnetic shielding layer is formed by picking a conductive metal element wire for a predetermined number of shots represented by the number of picks in the circumferential direction of the cable core , and the remaining number of shots. was formed with a pick of the soft magnetic metal filament, the number of strikes that are formed by the soft magnetic metal filament, braid density relative to the total beat number of metal strands occupying over the surface of the cable core 90 It is characterized by being configured to be at least%.

  According to the present invention having such characteristics, a high electromagnetic shielding effect can be obtained. That is, in the electromagnetic shielding layer, the part formed by the soft magnetic metal wire contributes to the magnetic shielding, and the part formed by the soft magnetic metal wire covers the surface of the cable core and occupies it. Since the density is secured at 90% or more (the braid density as a whole of the braid is secured at 95% or more), a high electromagnetic shielding effect can be obtained. The fact that the braid density of only the portion formed of the soft magnetic metal wire is 90% or more will be described in the best mode for carrying out the invention.

  In the present invention, the portion of the electromagnetic shielding layer that is formed of the conductive metal wire is formed of a soft magnetic metal wire if it is formed by a predetermined number of strikes, but in a normal braiding manner. Since it is always in contact with the portion to be made, the induced current flowing through the portion formed by the soft magnetic metal wire can be easily released.

The electromagnetic shielding cable of the present invention according to claim 2 is the electromagnetic shielding cable according to claim 1, wherein the conductive metal wire and the soft magnetic metal wire constituting the electromagnetic shielding layer (13) . The element wire diameters are both 0.1 mm to 0.2 mm.

  According to the present invention having such characteristics, the desired high electromagnetic shielding effect can be obtained by setting the wire diameters of the conductive and soft magnetic metal wires to 0.1 mm to 0.2 mm. And also contributes to the improvement of the flexibility of the cable. Needless to say, if the flexibility of the cable is improved, the workability and handleability of the cable are improved.

  Regarding the strand diameter, if the strand diameter is less than 0.1 mm, the flexibility of the cable is improved, but the desired high electromagnetic shielding effect may not be obtained. On the other hand, if the strand diameter exceeds 0.2 mm, the desired high electromagnetic shielding effect can be obtained, but the flexibility of the cable may be lowered.

  According to the first aspect of the present invention, there is an effect that an electromagnetic shielding cable capable of obtaining a high electromagnetic shielding effect can be provided. Moreover, according to the second aspect of the present invention, it is possible to contribute to the improvement of the flexibility of the cable as well as the high electromagnetic shielding effect.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a configuration diagram of a cable and an electromagnetic shielding layer showing an embodiment of an electromagnetic shielding cable of the present invention. Moreover, FIG. 2 is explanatory drawing regarding an electromagnetic shielding effect. In addition, the electromagnetic shielding layer in FIG. 1 shall be shown typically.

  In FIG. 1, an electromagnetic shielding cable 11 of the present invention includes a cable core 12, an electromagnetic shielding layer 13 provided on the cable core 12, and a sheath 14 covered on the electromagnetic shielding layer 13. Has been. The electromagnetic shielding layer 13 is braided as shown in the figure, and includes a bundle 15 of conductive metal strands and a bundle 16 of soft magnetic metal strands, which are features of the present invention. It is manufactured by braiding.

  The electromagnetic shielding layer 13 is formed of a bundle of soft magnetic metal strands having a braid density of 95% or more in the circumferential direction A of the cable core 12 as a whole braid covering and occupying the surface of the cable core 12. It is manufactured so that the braid density of only the portion is 90% or more in the circumferential direction A of the cable core 12.

  Here, in terms of braiding terms, the bundle of metal wires (15, 16) is called a pick (same as p described in the background section). This is made up of one or more metal strands, and the number of metal strands contained in one pick is called a number of ends, and the number of picks per round (circumferential direction A) is It is called number of spindles.

  Conductive metal wires and soft magnetic metal wires having the same wire diameter are used. The wire diameter applied in the present invention is in the range of 0.1 mm to 0.2 mm, and will be described later with reference to FIG. 2, but a desired high electromagnetic shielding effect can be obtained (this book). According to the invention, if the wire diameter exceeds 0.2 mm, the flexibility of the cable may be reduced).

  As the conductive metal wire, a wire made of annealed copper or tin-plated annealed copper having good conductivity characteristics is used. The use of such soft copper or tin-plated soft copper having an excellent conductive property has an advantage that the induced current flowing in the soft magnetic metal wire can be easily released. And it can be expected that an excellent electromagnetic shielding effect can be obtained.

  As the soft magnetic metal wire, one made of electromagnetic soft iron or iron silicon steel having good magnetic properties (high magnetic permeability) is used. By using such an electromagnetic soft iron or iron silicon steel, it can be expected that the magnetic shielding effect is increased and an excellent electromagnetic shielding effect can be obtained.

  The electromagnetic shielding layer 13 is formed of a bundle 15 of conductive metal strands for a predetermined number of shots represented by the number of picks in the circumferential direction A, and the remaining number of shots is soft magnetic. It is manufactured so as to be formed by a bundle 16 of metal wire portions. Further, as described above, the electromagnetic shielding layer 13 is manufactured so that the braid density of only the portion formed by the bundle 16 of soft magnetic metal wires is ensured to be 90% or more. These points are features of the present invention.

  With respect to the number of strikes, in this embodiment, the portion formed by the bundle 15 of the conductive metal strands is illustrated so that there is only one strike, so the portion formed by the bundle 16 of the soft magnetic metal strands is The striking numbers may be determined so that the braid densities of 90% and 95% can be secured. It should be noted that the portion formed by the bundle 15 of conductive metal wires may be two or more strokes. As shown in this embodiment, when the portion formed by the bundle 15 of conductive metal wires is only one stroke, the portion formed by the bundle 16 of soft magnetic metal wires is 19 strokes or more (in one example) As a result, the braid densities of 90% and 95% are ensured, respectively.

  Even if the portion formed by the bundle 15 of the conductive metal strands is formed only by a predetermined number of strikes, it is formed by the bundle 16 of the soft magnetic metal strands if the usual knitting method is used as shown in the figure. Since it is always in contact with the part, the induced current flowing in the part formed by the bundle 16 of the soft magnetic metal wires can be easily released.

  Known cable cores 12 and sheaths 14 are used. Briefly describing them, the cable core 12 is produced by, for example, manufacturing a plurality of insulation cores by covering a conductor with an insulator made of a thermoplastic resin such as polyvinyl chloride or polyethylene, and twisting the insulation cores. After the fitting, an intervention is provided to form a substantially circular shape in cross section, and after this, a press-wound tape is wound, and a sheath made of a thermoplastic resin such as polyvinyl chloride or polyethylene is extruded onto the press-wound tape. Manufactured by coating.

  The sheath 14 is provided to protect the electromagnetic shielding cable 11, and is made of, for example, a thermoplastic resin such as polyvinyl chloride or polyethylene. If necessary, the sheath 14 is made of a flame retardant, an ultraviolet absorber, a heat stabilizer, or an oxidation. It is manufactured by extrusion coating after blending known additives such as inhibitors.

  Next, the electromagnetic shielding effect of the electromagnetic shielding cable 11 of the present invention will be described with reference to FIG. In addition, FIG. 1 shall also be referred as needed.

  The vertical axis of the graph of FIG. 2 is an axis indicating the shielding effect (S [dB]). Further, the horizontal axis is an axis indicating the strand diameter (diameter t [mm]) of the soft magnetic metal strand. As a condition, the frequency of the noise source is 100 kHz, and the distance from the noise source is 0.1 m. The graph of FIG. 2 plots the shielding effect under this condition and shows this as a result.

  In the graph of FIG. 2, the result that rises to the right on the upper side is that the braid density of only the soft magnetic metal wires covering and occupying the surface of the cable core is 100% in the circumferential direction of the cable core. For example, it shows a shielding effect of the case where the entire surface of the cable core is covered with only soft magnetic metal wires without any gaps (100% is formed of a bundle 15 of conductive metal wires. It is excluded from the scope of the present invention because it does not include a portion). On the other hand, as a result of rising to the right on the lower side, the braid density of only the portion formed by the bundle 16 of soft magnetic metal wires as in the present invention is 90% in the circumferential direction A of the cable core 12. It shows the shielding effect when It can be seen that there is almost no difference between the two results.

  In the present invention, the criterion for determination is to have a shielding effect (electromagnetic shielding effect) of 40 [dB] or more (if at least 40 [dB], it is determined that the shielding effect is high). From the graph of FIG. 2, the braid density of only the portion formed by the bundle 16 of soft magnetic metal wires is 90% in the circumferential direction A of the cable core 12 as in the present invention. It can be seen that a high shielding effect can be obtained when the element wire diameter is in the range of 0.1 mm to 0.2 mm.

  In the present invention, when the strand diameter exceeds 0.2 mm, it is considered that although the high shielding effect is obtained, the flexibility of the cable may be lowered.

  As described above, as described with reference to FIGS. 1 and 2, according to the present invention, there is an effect that it is possible to provide the electromagnetic shielding cable 11 that can obtain a high electromagnetic shielding effect.

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is a block diagram which shows one Embodiment of the electromagnetic shielding cable of this invention, and an electromagnetic shielding layer. It is explanatory drawing regarding an electromagnetic shielding effect. It is a figure of the electromagnetic shielding cable of a prior art example, (a) is a block diagram of the whole cable, (b) is a block diagram of an electromagnetic shielding layer.

Explanation of symbols

A circumferential direction of cable core 11 electromagnetic shielding cable 12 cable core 13 electromagnetic shielding layer 14 sheath 15 bundle of conductive metal strands 16 bundle of soft magnetic metal strands

Claims (2)

The braid density of the entire braid covering and occupying the surface of the cable core is 95% or more in the circumferential direction of the cable core, which is a braid composed of conductive metal strands and soft magnetic metal strands. In an electromagnetic shielding cable having an electromagnetic shielding layer,
The braid comprises a braid of a pick of the conductive metal strand and a pick of the soft magnetic metal strand,
The electromagnetic shielding layer is formed by picking a conductive metal element wire for a predetermined number of shots represented by the number of picks in the circumferential direction of the cable core , and the remaining number of shots. Is formed with a pick of soft magnetic metal wire,
The number out of the soft magnetic metal filament constituting an electromagnetic shielding layer, the braid density relative to the total beat number of metal strands occupying over the surface of the cable core is configured so as to be 90% An electromagnetic shielding cable characterized by that. The electromagnetic shielding cable according to claim 1,
An electromagnetic shielding cable, wherein both the conductive metal strands and the soft magnetic metal strands constituting the electromagnetic shielding layer have a diameter of 0.1 mm to 0.2 mm.

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