JP2008078082A - Metallic cable - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metallic cable and a paired metallic cable with cross talk reduced and weight saved, and capable of being connected with an existing connector. <P>SOLUTION: An outer envelope is divided into an inner and an outer layers, a protrusion is formed inside the outside layer of the outer envelope so as to widen an interval between the outside layer of the outer envelope and the inside layer of the outer envelope, with metal core wires wrapped in the inside layer of the outer envelope. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a metallic cable that reduces crosstalk, reduces weight, and can be attached to an existing connector.

  As shown in FIG. 6, the paired metallic cable 101 which is a kind of metallic cable has a plurality of twisted wires 3 formed by twisting two insulated core wires 2, and each paired twisted wire 3 is one. The central interposition 5 is separated in the circumferential direction by the partition 4, and the outer skin 106 is provided on the outer periphery of the central interposition 5. The insulation core wire 2 is a metal core wire 108 provided with an outer skin (insulation coating) 109.

  The conventional pair-type metallic cable 101 can perform high-speed transmission of 1 Gbps at the maximum. The paired metallic cable 101 is required to have excellent transmission characteristics, and the frequency band is 250 MHz. The higher the frequency, the more difficult it is to improve the crosstalk between the twisted wires 3, the return loss, and the characteristic impedance. As a countermeasure, the structure shown in FIG. 6 is used. That is, by separating each pair of stranded wires 3 by a partition 4 in the circumferential direction one by one by a central cross 5 having a cross-shaped cross section, the crosstalk generated between each pair of stranded wires 3 can be reduced in return loss while adapting to the requirements. The characteristic impedance is also adapted to the requirements.

Japanese Patent Laid-Open No. 11-053958

  10GBASE-T, an Ethernet (registered trademark) with a transmission speed of 10 Gbps using a paired metallic cable, aiming for standardization in 2006 at the 802.3 standardization organization of IEEE (American Institute of Electrical and Electronics Engineers) The realization of In this 10 Gbps Ethernet (registered trademark), the bandwidth is expanded from the conventional maximum of 250 MHz to 500 MHz, and a crosstalk generated between adjacent pair-type metallic cables that has not been specified so far is newly specified. The

  Usually, in the communication cable wiring system, only one pair of four paired metallic cables 101 as shown in FIG. 6 is not wired, and a plurality of these four pairs of paired metallic cables 101 are adjacent to each other. Lay multiple lines. For this reason, an environment in which crosstalk between the paired metallic cables 101 easily occurs.

  In general, in order to satisfy the above-mentioned crosstalk definition between a pair-type metallic cable (hereinafter simply referred to as a metallic cable), it is necessary to make the twist pitch of the pair-twisted wire finer than before, and at the same time, the adjacent metallic It is effective to increase the distance between the twisted wires between the cables. This is because the crosstalk between the twisted wires is inversely proportional to the square of the distance between the twisted wires.

Therefore, in order to increase the distance between the twisted pairs of adjacent metallic cables, it is preferable to increase the outer diameter (diameter) of the outer cover. However, in order to increase the outer diameter of the outer skin, if the thickness of the outer skin is simply increased to 2 mm or 3 mm, for example,
1. The weight per unit length of cable increases.
2. Consumes a large amount of skin material.
3. Deviations in skin thickness tend to occur, and the cross-sectional shape is difficult to stabilize to a prescribed shape such as a circle.
4). Connectors suitable for conventional outer diameter cables, for example, 8-pole 8-core modular plugs compatible with the paired metallic cable in FIG. Cannot be installed.
There are disadvantages.

  Therefore, the present inventor has devised a pair-type metallic cable 111 as shown in FIG. This pair-type metallic cable 111 has a plurality of twisted wires 3 formed by twisting two insulated core wires 2, and has a central intervening 5 separating each pair of twisted wires 3 by a partition 4 in the circumferential direction one by one. The outer skin 6 is provided with an outer skin 6 on its outer periphery, and a projection 7 is formed on the outer skin 6 to widen the distance between the outer surface of the outer skin 6 and the central skin 5.

  The protrusion 7 has a trapezoidal cross section, and a plurality of protrusions 7 are arranged at regular intervals in the circumferential direction along the inner periphery of the outer skin 6, so that the outer skin 6 has a gear-like cross section. Although the protrusion 7 can be formed on the outer side of the outer skin 6, the distance between the twisted wires between adjacent cables can be increased, but here, it is formed on the inner side of the outer skin 6.

With this configuration, the distance between the outer surface of the outer skin 6 and the central interposition 5 is widened, and the outer diameter of the outer skin 6 is larger than that of the conventional paired metallic cable 101 shown in FIG. Thereby, when the several pair type metallic cable is made to adjoin, the distance between the twisted pair wires of adjacent cables can be enlarged conventionally. Therefore, the pair-type metallic cable 111 of FIG. 7 is compared with simply increasing the thickness of the outer skin,
1. The weight per unit length of cable does not increase much.
2. Does not consume large amounts of skin material.
3. Deviations in skin thickness are unlikely to occur, and the cross-sectional shape is likely to be stabilized to a prescribed shape such as a circle.
There is an advantage.

However, since this pair-type metallic cable 111 has a larger outer skin diameter than before,
4). An 8-pole 8-core modular plug (a type of connector) compatible with the paired metallic cable 101 of FIG. 6 cannot be attached.
5. When lateral pressure is applied, the protrusions apply local stress to the twisted pair.
There is a disadvantage. In particular, the fact that it cannot be assembled with an existing connector is a major obstacle in practice.

  Therefore, an object of the present invention is to provide a metallic cable that solves the above problems, reduces crosstalk, reduces weight, and can be attached to an existing connector.

  In order to achieve the above object, the metallic cable of the present invention has an outer skin divided into inner and outer double parts, and the protrusions are formed inside the outer skin so as to widen the distance between the outer skin and the inner skin. A metal core wire is included in the inner skin.

  The metal core wire may be an insulating core wire provided with an insulating coating.

  The metal core wire may be a twisted pair wire in which two insulating core wires are twisted together.

  The inner shell includes a plurality of twisted wires in which two insulating core wires are twisted as the metal core wires, and a central interposition that separates each pair of twisted wires one by one in the circumferential direction. May be.

  A plurality of the protrusions may be formed at intervals in the circumferential direction.

  The outer diameter of the inner skin may be 6.4 mm or less, and the outer diameter of the outer skin may be 8 mm or more.

  The present invention exhibits the following excellent effects.

  (1) Crosstalk can be reduced.

  (2) The weight can be reduced.

  (3) It can be attached to an existing connector.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the metallic cable 1 according to the present invention is a further improvement of the paired metallic cable 111 of FIG. 7, wherein the outer skin is divided into inner and outer doubles, and the outer outer skin is formed inside the outer outer skin. This is a pair-type metallic cable 1 in which the protrusions are formed so as to widen the distance between the inner skin and the inner skin.

  Here, four twisted wires 3 are provided. Therefore, the number of the insulation core wires 2 is eight. Further, the central interposition 5 has four partitions 4 for isolating each pair of twisted wires 3 one by one in the circumferential direction, and is formed in a cross shape in cross section. Of course, the number of the twisted wires 3 is not limited to this, and may be any number.

  The structure of the twisted pair 3 and the central interposition 5 is the same as the paired metallic cable 111 of FIG. When the difference from the paired metallic cable 111 of FIG. 7 is described, the paired metallic cable 1 of FIG. 1 has a double structure in which the outer skin 6 is divided into inner and outer outer skins 12 and 13, and the outer outer skin 12. A projection 14 is formed on the inside of the projection. In this case, a space is intentionally included between the outer skin 12 and the inner skin 13 by increasing the distance between the outer skin 12 and the inner skin 13. Thereby, while suppressing an increase in weight per unit length of the cable, the outer diameter of the cable can be increased to increase the distance between the twisted wires between adjacent cables, thereby effectively suppressing crosstalk.

In addition, since the paired metallic cable 1 of FIG. 1 has the outer skin 6 doubled, only the outer skin 12 can be peeled off leaving the inner skin 13, so that the outer diameter of the inner skin 13 can be reduced. If the outer diameter of the outer shell 12 of the conventional paired metallic cable 101 shown in FIG. 6 is the same as that of the conventional metallic cable 101, the outer connector 12 can be peeled to assemble with an existing connector.
Therefore, the pair-type metallic cable 1 of FIG.
1. The weight per unit length of cable does not increase much.
2. Does not consume large amounts of skin material.
3. Deviations in skin thickness are unlikely to occur, and the cross-sectional shape is likely to be stabilized to a prescribed shape such as a circle.
4). An 8-pole 8-core modular plug compatible with the paired metallic cable of FIG. 6 is attached.
5. Even if a lateral pressure is applied, there is an inner skin, so that no local stress is applied to the twisted pair.
There is an advantage.

  As a result, the paired metallic cable 1 according to the present invention not only conforms to strict requirements regarding electrical characteristics such as crosstalk between the pairs in the cable, return loss, and characteristic impedance, but also when the cables are adjacent to each other. The cable-to-cable crosstalk also meets the requirements, and further, compared with the conventional pair-type metallic cable 101, the economy, usability and productivity are comparable, and the practicality is excellent.

  Next, a method of assembling the paired metallic cable 1 of FIG. 1 with an existing connector will be described.

  The outer diameter of the cable received by the existing 8-pole 8-core modular plug is up to 6.5 mm. This is because the maximum outer diameter of the paired metallic cable is defined as 6.4 mm in TIA / EIA (American Telecommunications Industry Association / American Electronics Industry Association) 568B-2. Accordingly, it is desirable that the outer diameter of the inner skin 13 of the pair-type metallic cable 1 of FIG. 1 is 6.4 mm or less.

  By setting the outer diameter of the inner skin 13 to 6.4 mm or less, when the outer skin 12 is peeled off, the existing 8-pole 8-core modular plug can be attached by a conventional method.

  As shown in FIG. 2, when the outer skin 12 is peeled off at the end of the paired metallic cable 1, the inner skin 13 is exposed. The terminal in which the inner skin 13 is exposed is adapted to the outer diameter of the 8-pole 8-core modular plug 21.

  When the outer diameter of the inner skin 13 is 6.4 mm, the outer diameter of the outer skin 12 is desirably 8 mm or more. That is, it is desirable that the thickness (projection part) of the outer skin 12 is 2 mm or more. As a result, the outer diameter of the paired metallic cable 1 of FIG. 1 is increased by 2 mm compared to the conventional paired metallic cable 101, and thereby the distance between the paired strands can be sufficiently increased between adjacent cables.

  Next, the crosstalk characteristic between cables when a plurality of paired metallic cables of FIG. 1 are adjacently wired will be described.

  As shown in FIG. 3, the required value of crosstalk between cables in 10GBASE-T, which is the IEEE standard, is 62.5 dB or more at 100 MHz and 52 dB or more at 500 MHz when expressed as near-end crosstalk between cables. is there. On the other hand, the paired metallic cable 11 of the present invention has crosstalk values of the first pair, the second pair, the third pair, and the fourth pair of the paired metallic cables 1 adjacent to each other. The required value of 10GBASE-T is satisfied in the entire frequency band.

Here, the inter-cable power sum near-end crosstalk is stored in the adjacent pair-type metallic cable B when a signal of voltage Vin is applied to the target pair-stranded wire housed in the target pair-type metallic cable A. If the voltage appearing between the four twisted wires is Vb1, Vb2, Vb3, Vb4,
20 log ₁₀ {(Vb1 + Vb2 + Vb3 + Vb4) / Vin}
It is a value defined by. The larger the absolute value of this value, the smaller the crosstalk noise.

  A pair-type metallic cable 41 shown in FIG. 4 is a modification of the pair-type metallic cable 1 shown in FIG. 1, and the number of protrusions 14 is reduced. In other words, a total of 12 protrusions 14 are provided for every 30 ° circumferential angle. Since the width (circumferential direction) of the protrusions 14 is not significantly different from the width of the protrusions 14 in the pair-type metallic cable 1 of FIG. 1, the smaller the number of protrusions 14, the greater the proportion of space occupied, which is advantageous for weight reduction. .

  In the embodiments described so far, the present invention is applied to the pair-type metallic cable. However, the present invention is not limited to this and can be applied to metallic cables having any structure. For example, the present invention is applied to a metallic cable that has a simple structure and a metallic cable that only has a sheath on the outer periphery of the metal core. That is, as shown in FIG. 5A, the metallic cable 51 has a double-sided outer skin and a protrusion 54 that extends inside the outer skin 52 so as to widen the space between the outer skin 53 and the inner skin 53. Form. As a result, the distance between the metal cores between adjacent cables can be increased to reduce crosstalk, the increase in the material of the outer skin can be suppressed, and the weight can be reduced. Further, FIG. As shown in FIG. 2, if the outer skin 52 is peeled off, it can be attached to an existing connector.

  In this way, the outer skin is divided into inner and outer double parts, a protrusion is formed on the inner side of the outer skin so as to widen the distance between the outer skin and the inner skin, and a metal core is included in the inner skin. If it is, the crosstalk between cables can be reduced, the weight can be reduced, and it can be attached to an existing connector regardless of the number of metal core wires and the presence or absence of interposition.

It is sectional drawing of the pair type metallic cable which shows one Embodiment of this invention. It is a figure which shows the method of assembling the pair type metallic cable of FIG. 1 with the existing connector. FIG. 3 is a crosstalk characteristic diagram between cables of the paired metallic cable of FIG. 2. It is sectional drawing of the pair type metallic cable which shows one Embodiment of this invention. (A) is sectional drawing of the metallic cable which shows one Embodiment of this invention, (b) is an assembly figure. It is sectional drawing of the conventional pair type metallic cable. It is sectional drawing of the pair type metallic cable which improved the conventional pair type metallic cable.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 Pair-type metallic cable 2 Insulation core wire 3 Paired strand 4 Partition 4 5 Center intervention 6 Outer skin 7, 14 Protrusion 12 Outer skin 13 Inner skin

Claims (6)

  The outer skin was divided into inner and outer double parts, the protrusions were formed inside the outer skin so as to widen the distance between the outer skin and the inner skin, and the metal core was included in the inner skin. Metallic cable characterized by   2. The metallic cable according to claim 1, wherein the metal core wire is an insulating core wire provided with an insulating coating.   The metallic cable according to claim 1 or 2, wherein the metal core wire is a twisted pair wire in which two insulating core wires are twisted together.   The inner shell includes a plurality of twisted wires in which two insulating core wires are twisted as the metal core wires, and a central interposition that separates each pair of twisted wires one by one in the circumferential direction. 3. The metallic cable according to 1 or 2, wherein   5. The metallic cable according to claim 1, wherein a plurality of the protrusions are formed at intervals in the circumferential direction.   5. The metallic cable according to claim 4, wherein an outer diameter of the inner skin is 6.4 mm or less, and an outer diameter of the outer skin is 8 mm or more.

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