Communication cable

Abstract

To provide a communication cable having electrical characteristics, capacitance and conductor resistance.SOLUTION: The communication cable includes a plurality of twisted pairs in which a plurality of insulated wires each having a conductor and an insulating layer covering the conductor are twisted in one direction, a press-winding layer covering the plurality of twisted pairs, and a shielding layer covering the press-winding layer. A length between the conductors and the shielding layer is more than 0. 2325mm and less than 0. 7225mm, and a collective twist pitch of the plurality of twisted pairs is more than 20mm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a communication cable. [Background technology]

[0002] In recent years, communication cables such as LAN (Local Area Network) cables have been used to connect a variety of devices, such as between servers, between servers and switches, between servers and personal computers, sensors for robots, and gigabit-capacity cameras, and are therefore required to be suitable for high-speed data communication.

[0003] Patent Document 1 describes a cable for movable parts that includes a plurality of twisted electric wires, a tape layer that covers the plurality of electric wires, and a shielding layer that covers the tape layer. The electric wire includes a conductor in which a plurality of metal wires are twisted together, and an insulator that covers the conductor. The cable for movable parts in Patent Document 1 has partial gaps between the tape layer and the shielding layer to enhance the flexibility and bending resistance of the cable for movable parts. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-36486 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the cable for moving parts described in Patent Document 1 cannot comply with Category 6A (Cat. 6A) or higher of the ANSI / TIA-568 standard. Cat. 6A requires that the return loss, capacitance, and conductor resistance satisfy certain conditions. Therefore, when a cable for moving parts such as that described in Patent Document 1 is used for high-speed data communication, there is room for improvement in the return loss, conductor resistance, and capacitance.

[0006] Therefore, an object of the present invention is to provide a communication cable that satisfies the requirements for return loss, conductor resistance, and capacitance in the Category 6A standard. [Means for solving the problem]

[0007] In order to solve the above problem, according to one aspect of the present invention, a plurality of twisted-pair wires in which a plurality of insulated wires, each having a conductor and an insulating layer covering the conductor, are twisted together in one direction; a winding that covers the plurality of twisted wire pairs; a shielding layer covering the winding layer; and the distance between the conductor and the shielding layer is greater than 0.2325 mm and less than 0.7225 mm; The twist pitch of the plurality of twisted pairs is greater than 20 mm. A communications cable is provided. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a communication cable that satisfies the requirements for return loss, conductor resistance, and capacitance of Cat. 6A. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a communication cable according to an embodiment of the present invention. [Figure 2] FIG. 2 is a flowchart of a method for manufacturing a communication cable according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes communication cables according to embodiments of the present invention. However, the communication cables of the present invention are not limited to the embodiments described below. In this specification, the symbol "to" indicating a range of values ​​means that the upper and lower limits of the range are included.

[0011] (Communication cable configuration) FIG. 1 is a cross-sectional view of a communication cable 10 according to an embodiment of the present invention.

[0012] The communication cable 10 is a so-called LAN cable, and includes a plurality of twisted pairs 20, a winding layer 40, and a shielding layer 50. In addition to the above configuration, the communication cable 10 may also include a spacer 30 and an outer sheath layer 60. As shown in FIG. 1 , in this embodiment, the communication cable 10 includes a plurality of twisted pairs 20, a spacer 30, the winding layer 40, the shielding layer 50, and the outer sheath layer 60.

[0013] The communication cable 10 has a plurality of twisted pairs 20 and interposers 30 twisted together in a fixed direction at a predetermined twisting pitch. Here, "twisting pitch" refers to the longitudinal distance of the plurality of twisted pairs 20 or interposers 30 required for a pair of twisted pairs 20 to make one circuit when the plurality of twisted pairs 20 and interposers 30 are twisted together. The number of twisted pairs 20 is not particularly limited as long as there is more than one. In this embodiment, the number of twisted pairs 20 is four.

[0014] The lower limit of the twisting pitch is more than 20 mm. If the lower limit of the twisting pitch is 20 mm or less, the length of the insulated wires 21 per meter of the communication cable 10 becomes too long, resulting in poor conductor resistance. The upper limit of the twisting pitch varies depending on the configuration of the winding layer 40 in the twisted pair wire 20. When the winding layer 40 is a resin film, the upper limit of the twisting pitch is preferably less than 50 mm in order to improve bending characteristics. When the winding layer 40 is a resin tube, the upper limit of the twisting pitch is preferably less than 80 mm in order to improve bending characteristics.

[0015] Each of the multiple twisted pair wires 20 has two insulated wires 21. The two insulated wires 21 are twisted together in a fixed direction at a predetermined twist pitch. Here, the "twist pitch" refers to the distance in the longitudinal direction of the twisted pair wire 20 required for one insulated wire 21 to make one turn when two insulated wires 21 are twisted together.

[0016] The insulated wire 21 has a conductor 22 and an insulating layer 23 that covers the conductor 22 .

[0017] The conductor 22 is a conducting wire made of a conductive metal material. The type of conductor 22 is not particularly limited as long as it is made of a conductive metal material. The conductor 22 may be a solid wire or a twisted wire made by twisting together multiple wires. In this embodiment, the conductor 22 is made by twisting together multiple annealed copper wires. The conductor 22 is twisted so that the multiple annealed copper wires have a predetermined twist pitch. Here, the "twist pitch" means the distance in the longitudinal direction of the conductor 22 required for any one annealed copper wire to make one turn when multiple annealed copper wires are twisted together.

[0018] The thickness of the conductor 22 (diameter of the cross section perpendicular to the longitudinal direction) is not particularly limited. The thickness of the conductor 22 is selected appropriately depending on the use and type of the communication cable 10. The diameter of the conductor 22 is, for example, within a range of 0.34 to 0.42 mm. In this embodiment, the diameter of the conductor 22 is 0.38 mm.

[0019] The insulating layer 23 covers the conductor 22. The material of the insulating layer 23 is not particularly limited as long as it has insulating properties. In the present embodiment, the insulating layer 23 is made of polyethylene. The thickness of the insulating layer 23 is not particularly limited as long as the distance between the conductor 22 and the shielding layer 50 falls within a predetermined range. The thickness of the insulating layer 23 is set in relation to the thickness of the winding layer 40 so that the distance between the conductor 22 and the shielding layer 50 falls within a predetermined range. The thickness of the insulating layer 23 is preferably within a range of 0.10 to 0.30 mm, and more preferably within a range of 0.12 to 0.15 mm.

[0020] The insert 30 separates the multiple twisted pairs 20 from one another. The insert 30 extends in the longitudinal direction of the communication cable 10. The shape of the insert 30 is not particularly limited as long as it can separate the multiple twisted pairs 20 from one another. In this embodiment, the cross-sectional shape of the insert 30 perpendicular to the extension direction is a plus sign shape. That is, in this embodiment, the insert 30 is a cross insert. The material of the insert 30 is also not particularly limited as long as it can perform the above-mentioned function. In this embodiment, the material of the insert 30 is polyethylene. The insert 30 is twisted together with the multiple twisted pairs 20 along the longitudinal direction of the communication cable 10 at a twisting pitch.

[0021] The winding layer 40 covers the twisted pairs 20 and the interposer 30 on the inner side of the shielding layer 50. The winding layer 40 maintains a constant distance between the twisted pairs 20 and the shielding layer 50. The winding layer 40 is wound or extruded over the twisted pairs 20 and the interposer 30. The thickness of the winding layer 40 is not particularly limited as long as the distance between the conductor 22 and the shielding layer 50 is within a predetermined range. The thickness of the winding layer 40 is set in relation to the thickness of the insulating layer 23 so that the distance between the conductor 22 and the shielding layer 50 is within a predetermined range. The thickness of the winding layer 40 is preferably within a range of 0.05 to 0.20 mm, for example, and more preferably within a range of 0.10 to 0.20 mm.

[0022] The structure of the winding layer 40 is not particularly limited as long as it can perform the above-mentioned functions. The winding layer 40 may be made of a resin film or a resin tube.

[0023] When the winding layer 40 is a resin film, examples of the resin film material include polyester, polypropylene, polyethylene, nylon, aramid fiber, and acrylic fiber. In this specification, the term "resin film" encompasses not only thin resin films but also nonwoven fabrics, woven fabrics, and the like. In this embodiment, when the winding layer 40 is made of a resin film, the material of the winding layer 40 is polypropylene tape. The number of winding layers 40 is not particularly limited as long as it does not impair the purpose and effect of this embodiment. The width of the resin film is preferably greater than 5 mm and less than 25 mm. For example, the width of the resin film is 15 mm. The resin film is wound transversely with respect to the twisted pair wires 20 and the interposer 30. Here, "transversely wound" means that the resin film is wound spirally so that a portion of the resin film overlaps the twisted pair wires 20 and the interposer 30.

[0024] When the winding layer 40 is a resin tube, it is formed by extrusion molding, for example. Examples of materials for the resin tube include polyethylene, polyester, and polypropylene. Polyethylene may also contain ethylene vinyl acetate (EVA). In this embodiment, when the winding layer 40 is a resin tube, the resin tube is a polyethylene tube.

[0025] The shielding layer 50 covers the winding layer 40 on the inner side of the outer jacket layer 60. The shielding layer 50 shields from external noise and protects the multiple twisted pairs 20 and the interposer 30. The shielding layer 50 has a first shielding layer 51 that covers the winding layer 40, a second shielding layer 52 that covers the first shielding layer 51, and a drain wire 53 that is arranged outside the first shielding layer 51 and inside the second shielding layer 52.

[0026] The first shielding layer 51 covers the winding layer 40. The first shielding layer 51 is, for example, a metal laminate tape. Examples of metal laminate tapes include Al / PET tape in which aluminum foil (Al) is laminated on a polyethylene terephthalate film. In this embodiment, the first shielding layer 51 is an Al / PET tape. The first shielding layer 51 is wound transversely on the winding layer 40 along the longitudinal direction of the communication cable 10. The thickness of the first shielding layer 51 is, for example, in the range of 0.01 to 0.1 mm. A drain wire 53 is arranged on the outside of the first shielding layer 51.

[0027] The drain wire 53 functions as a ground wire and is, for example, a tin-plated annealed copper wire having an outer diameter in the range of 0.2 to 0.5 mm.

[0028] The second shielding layer 52 covers the first shielding layer 51. The second shielding layer 52 is, for example, a tin-plated annealed copper wire braid.

[0029] The outer sheath layer 60 is made of resin and covers the second shielding layer 52. The outer sheath layer 60 protects the shielding layer 50 together with the multiple twisted pairs 20, the filler 30, and the push-up layer 40. The outer sheath layer 60 may be a single layer or multiple layers. In this embodiment, the outer sheath layer 60 has a single-layer structure. The material of the outer sheath layer 60 is a resin, and is not particularly limited as long as it can perform the above-mentioned functions. Examples of materials for the outer sheath layer 60 include polyvinyl chloride and polyolefin. In this embodiment, the material of the outer sheath layer 60 is polyvinyl chloride. The thickness of the outer sheath layer 60 is not particularly limited. The thickness of the outer sheath layer 60 is, for example, within a range of 0.3 to 1.0 mm, and more preferably within a range of 0.3 to 0.5 mm. In this embodiment, the thickness of the outer sheath layer 60 is, for example, 0.35 mm.

[0030] In the communication cable 10 according to this embodiment, the distance L between the conductor 22 and the shielding layer 50 is greater than 0.2325 mm and less than 0.7225 mm, and preferably greater than or equal to 0.3225 mm and less than or equal to 0.5325 mm. In other words, in this embodiment, the sum of the thickness of the insulating layer 23 and the thickness of the winding layer 40 is greater than 0.2325 mm and less than 0.7225 mm, and preferably greater than or equal to 0.3225 mm and less than or equal to 0.5325 mm.

[0031] Here, "distance L between conductor 22 and shielding layer 50" is the shortest distance between conductor 22 and shielding layer 50 (see the double-headed arrow in FIG. 1). The distance L between conductor 22 and shielding layer 50 is measured at multiple locations for each of the four twisted pairs 20 (eight insulated wires 21). The measurement method is not particularly limited. For example, the communication cable 10 is cut at any position in a direction perpendicular to the longitudinal direction, and the distance L is measured for each insulated wire 21.

[0032] The distance L between the conductor 22 and the shielding layer 50 does not necessarily have to be satisfied for all insulated wires 21. For example, it is sufficient that more than half of the insulated wires 21 included in the communication cable 10 satisfy the distance L. In this embodiment, the condition for the distance L between the conductor 22 and the shielding layer 50 is satisfied for all insulated wires 21.

[0033] If the distance L between the conductor 22 and the shielding layer 50 is greater than 0.2325 mm and less than 0.7225 mm (greater than 0.3225 mm and less than 0.5325 mm), the distance between the conductor 22 and the shielding layer 50 (first shielding layer 51) is appropriate, and the return loss and capacitance requirements of Category 6A of the ANSI / TIA-568 standard can be met.

[0034] (Communication cable manufacturing method) FIG. 2 is a flowchart of a method for manufacturing the communication cable 10 according to the first embodiment.

[0035] The communication cable 10 can be manufactured, for example, by the following method. Here, the communication cable 10 having a plurality of twisted pairs 20, a filler 30, a winding layer 40, a shielding layer 50, and an outer jacket layer 60 will be described.

[0036] As shown in FIG. 2, the manufacturing method of the communication cable 10 includes a step (S110) of preparing a plurality of twisted pairs 20 twisted in one direction at a predetermined twisting pitch, a step (S120) of forming a winding layer 40, a step (S130) of forming a shielding layer 50, and a step (S140) of forming an outer sheath layer 60.

[0037] In the step (S110) of preparing a plurality of twisted pairs 20, polyethylene is extruded from the die of an extruder while conveying a plurality of annealed copper wires twisted in one direction at a predetermined twist pitch in the length direction, and conductors 22 are coated with insulating layer 23 to form insulated wires 21. Next, a plurality of insulated wires 21 (two in this case) are gathered together and twisted in one direction at a predetermined twist pitch to form twisted pairs 20. Next, interposers 30 are arranged so that the twisted pairs 20 do not come into contact with each other, and then the twisted pairs 20 and interposers 30 are twisted together.

[0038] In the step (S120) of forming the winding layer 40, the winding layer 40 is formed around the plurality of twisted pairs 20 and the interposers 30. Specifically, the winding layer 40 is formed by twisting the plurality of twisted pairs 20 and the interposers 30 in a fixed direction at a predetermined twisting pitch and then winding a polypropylene tape across the twisted pairs 20 and the interposers 30. Alternatively, in this embodiment, the winding layer 40 is formed by extruding polyethylene into a tube shape around the plurality of conductors 22 and the interposers.

[0039] Here, the thickness of the insulating layer 23 and the thickness of the winding layer 40 are adjusted so that the distance between the conductor 22 and the shielding layer 50 is greater than 0.2325 mm and less than 0.7225 mm.

[0040] In the step (S130) of forming the shielding layer 50, the shielding layer 50 is formed on the winding layer 40. Specifically, in this embodiment, first, an Al / PET tape is wound horizontally to form the first shielding layer 51, and then the first shielding layer 51 is covered with a tin-plated soft copper wire braid to form the second shielding layer 52.

[0041] In the step (S140) of forming the outer sheath layer 60, the outer sheath layer 60 is formed on the plurality of twisted pairs 20 and the interposer 30 on which the winding layer 40 and the shielding layer 50 have been formed. Specifically, in this embodiment, polyvinyl chloride is extruded from the die of an extruder to cover the shielding layer 50 with the outer sheath layer 60, thereby obtaining the communication cable 10.

[0042] (effect) As described above, according to the present invention, the distance between the conductor 22 and the shielding layer 50 is greater than 0.2325 mm and less than 0.7225 mm, and the twist pitch of the multiple twisted pairs 20 is greater than 20 mm, thereby improving the return loss, conductor resistance, and capacitance of Category 6A of the ANSI / TIA-568 standard. [Example]

[0043] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited by these examples, and the embodiments can be modified without departing from the spirit of the present invention.

[0044] 1. Making a communication cable (1) Preparation of communication cable 1 Polyethylene was extrusion-coated around multiple annealed copper wires (conductors) to form an insulated wire with an insulating layer. Two insulated wires were then twisted together to form a twisted pair wire. Four twisted pairs were then placed around a polyethylene cross insert, twisted together to a twisting pitch of 70 mm, and a 0.2 mm thick polypropylene tape was then wound around the twisted pair layer in a 1 / 2 overlap (with the tape overlapping by 1 / 2 the tape width) to form a push-winding layer. A 12 μm thick Al / PET tape was then wound around in a 1 / 4 overlap to form a first shielding layer. The first shielding layer was then covered with a tin-plated annealed copper wire braid to form a second shielding layer. A communication cable 1 of Example 1 was fabricated using polyvinyl chloride extrusion coating and having a 0.35 mm thick outer jacket layer. The distance between the conductor and the shielding layer of the communication cable 1 was within the range of 0.5225 to 0.5325 mm.

[0045] (2) Preparation of communication cable 2 Next, four twisted pairs were arranged around a polyethylene cross insert and twisted together at a twisting pitch of 70 mm, and a polyethylene extrusion coating with a thickness of 0.2 mm was applied as a winding layer to obtain a communication cable 2 of Example 2 in the same manner as communication cable 1. The distance between the conductor and the shielding layer of communication cable 2 was within the range of 0.5225 to 0.5325 mm.

[0046] (3) Manufacturing of communication cables 3 to 45 Communication cables 3, 6, 9 to 23, 28, and 30 to 43 of Examples 3, 6, and 9 to 23 and Comparative Examples 3, 5 to 18 were fabricated in the same manner as communication cable 1 of Example 1, with the constituent requirements of the communication cables being as shown in Tables 1 and 2. Communication cables 4, 5, 7, 8, 24 to 27, 29, 44, and 45 of Examples 4, 5, 7, 8, 24, and 25 and Comparative Examples 1, 2, 4, 19, and 20 were fabricated in the same manner as communication cable 2 of Example 2, with the constituent requirements of the communication cables being as shown in Tables 1 and 2.

[0047] 2. Evaluation (1) Evaluation of return loss For each communication cable wound to a 120mm inner diameter, the return loss (RL) between 0.772 and 500MHz was measured at 801 points using a network analyzer. The evaluation criteria for return loss (RL) were as follows, based on the minimum margin of error from the standard value described in "6.4.6 Return loss (Category 6A)" of "6. TRANSMISSION REQUIREMENTS" in the ANSI / TIA-568.2-D standard. Evaluation criteria ○: Minimum width is 1.0 dB or more △: Minimum width is 0 dB or more and less than 1.0 dB ×: Minimum width is less than 0 dB

[0048] (2) Conductor resistance evaluation Conductor resistance was measured in accordance with "6.6.1 Horizontal cable dc resistance" of the ANSI / TIA-568-2.D standard. Conductor resistance was evaluated according to the following criteria. ○:23.6Ω / 100m or less ×:23.6Ω / over 100m

[0049] (3) Evaluation of capacitance The capacitance was measured in accordance with "6.6.4 Horizontal cable Mutual capacitance" of the ANSI / TIA-568-2.D standard. The capacitance was evaluated according to the following criteria: ○: 5.6nF or less ×: More than 5.6nF

[0050] (4) Evaluation of bending characteristics Each communication cable was cut to a length of 1.6 m, and with a load of 300 gf applied to one end, it was bent near the middle of the cable with a bending radius of 25 mm, a bending angle of ±90°, and a bending speed of 60 cycles / min. The bending characteristics were evaluated in parallel with a conductivity test. The bending characteristics were evaluated according to the following criteria. ○: No breakage even after bending more than 300,000 times ×: Breakage after less than 300,000 bending cycles

[0051] (5) Evaluation of near-end crosstalk attenuation The near-end crosstalk attenuation was evaluated in accordance with "6.6.9 Horizontal cable NEXT Ioss" of the ANSI / TIA-568-2.D standard, by measuring each communication cable wound on a sheath (with an inner diameter of 120 mm) at 801 points between 0.772 and 500 MHz using a network analyzer, and determining the minimum margin from the standard value below. The near-end crosstalk attenuation was evaluated according to the following criteria. ○: Minimum margin is 2.0 dB or more △: Minimum margin is 0dB or more and less than 2.0dB ×: Minimum margin is less than 0 dB

[0052] (6) Overall evaluation The overall evaluation was based on the following criteria. ○: All the results of (1) to (3) above were "○", and the results of (4) and (5) above were "○". △: The evaluation results of (1) to (3) above were "○" ×: Any of the evaluation results in (1) to (3) above was “×”

[0053] Tables 1 and 2 show the parameters of the manufactured communication cables and the evaluation results.

[0054] [Table 1]

[0055] [Table 2]

[0056] As shown in Tables 1 and 2, communication cables 1 to 25 of Examples 1 to 25, in which the distance between the conductor and the shielding layer was greater than 0.2325 mm and less than 0.7225 mm (greater than 0.3225 mm and less than 0.5325 mm) and the twisting pitch of the multiple twisted pairs was greater than 20 mm, had good return loss, conductor resistance, and capacitance. In particular, the communication cables 15 to 23 of Examples 15 to 23, in which the winding layer was a resin film and the twisting pitch was less than 50 mm, had even better bending properties. Furthermore, the communication cables 2, 4, 5, 7, 8, 24, and 25 of Examples 2, 4, 5, 7, 8, 24, and 25, in which the wound layer was a resin tube and the twisting pitch was less than 80 mm, had even better bending properties.

[0057] On the other hand, the communication cables 26, 39 to 45 of Comparative Examples 1, 14 to 20, which had a twist pitch of 80 mm or more or a twist pitch of 20 mm or less, exhibited poor near-end crosstalk attenuation. Furthermore, the communication cables 39 to 45 of Comparative Examples 14 to 20, which had a twisting pitch of 20 mm or less, had poor conductor resistance, which is thought to be due to the increased length of the insulated wire per meter of the communication cable. The communication cables 29, 30, 32, 34, 36, 38, and 43 of Comparative Examples 4, 5, 7, 9, 11, 13, and 18, in which the distance L between the conductor and the shielding layer was 0.2325 mm or less, had poor capacitance. The communication cables 28, 30 to 343 of Comparative Examples 3 and 5 to 9, in which the winding layer was a resin film and the twisting pitch was 50 mm or more, had poor bending properties. [Industrial Applicability]

[0058] The communication cable according to the present invention is useful as a LAN cable capable of high-speed communication. [Explanation of symbols]

[0059] 10 Communication Cable 20 twisted pair wire 21 Insulated wire 22 Conductor 23 Insulating layer 30 intervention 40 Rolled layer 50 shielding layer 51 1st shielding layer 52 Second shielding layer 60 Outer layer

Claims

1. a plurality of twisted-pair wires in which a plurality of insulated wires, each having a conductor and an insulating layer covering the conductor, are twisted together in one direction; a winding layer that covers the plurality of twisted wire pairs; a shielding layer covering the winding layer; and the distance between the conductor and the shielding layer is greater than 0.2325 mm and less than 0.7225 mm; The twist pitch of the plurality of twisted pairs is greater than 20 mm. Communication cable.

2. 2. The communication cable of claim 1, The wrapping layer is a resin film, The twisting pitch is less than 50 mm. Communication cable.

3. 2. The communication cable of claim 1, The wound layer is a resin tube, The twisting pitch is less than 80 mm. Communication cable.

4. 2. The communication cable of claim 1, The insulating film further comprises an outer covering layer that covers the shielding layer. Communication cable.

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