Communication cable

Abstract

To provide a communication cable that can meet the return loss, near-end crosstalk loss, and conductor resistance requirements of Category 6A standards. [Solution] The communication cable comprises a plurality of stranded wires, each having a conductor and an insulating layer covering the conductor, twisted together in one direction; a winding layer covering the plurality of stranded wires; and a shielding layer covering the winding layer. The shielding layer includes an insulating layer and a conductive layer laminated on the insulating layer. The distance between the conductor and the shielding layer is 0.150 mm or more and less than 0.230 mm. The aggregate pitch of the plurality of stranded wires is greater than 20 mm and less than 80 mm. The conductive layer has a plurality of slits formed therein that electrically divide the conductive layer.

Description

Technical Field

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

Background Art

[0002] In recent years, communication cables such as LAN (Local Area Network) cables are used for connecting various devices such as between servers, between servers and switches, between servers and personal computers, robot sensors, cameras with a giga capacity, etc., and are required to be suitable for high-speed data communication.

[0003] Patent Document 1 describes a LAN cable having a plurality of twisted wires, a tape layer covering the plurality of wires, and a shield layer covering the tape layer. The wire has a conductor in which a plurality of metal strands are twisted and an insulator covering the conductor. In the LAN cable of Patent Document 1, by partially providing a gap between the tape layer and the shield layer, the flexibility and bending resistance of the LAN cable are enhanced.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the LAN cable described in Patent Document 1 cannot comply with the ANSI / TIA-568 standard Category 6A (Cat.6A) or higher. Category 6A requires that the return loss (RL), near-end crosstalk (NEXT), and conductor resistance meet predetermined conditions. Therefore, when using a LAN cable like the one described in Patent Document 1 for high-speed data communication, there is room for improvement in terms of return loss, near-end crosstalk, and conductor resistance.

[0006] Therefore, the object of the present invention is to provide a communication cable that can satisfy the conditions for return loss, near-end crosstalk loss, and conductor resistance in the Category 6A standard. [Means for solving the problem]

[0007] To solve the above problems, according to one aspect of the present invention, Multiple stranded wires, each having a conductor and an insulating layer covering the conductor, are twisted together in one direction. The aforementioned multiple stranded wires are covered by a pressing layer, A shielding layer covering the aforementioned winding layer, It has, The aforementioned shielding layer is The base layer, A conductive layer laminated on the aforementioned base layer, Includes, The distance between the conductor and the shielding layer is 0.150 mm or more and less than 0.230 mm. The combined twist pitch of the aforementioned multiple stranded wires is greater than 20 mm and less than 80 mm. The conductive layer has a plurality of slits formed therein that electrically divide the conductive layer. A communication cable will be provided. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a communication cable that can satisfy the conditions for return loss, near-end crosstalk loss, and conductor resistance in the Category 6A standard. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view of a communication cable according to an embodiment of the present invention. [Figure 2] Figures 2A to 2C show the structure of the shielding layer. [Figure 3] Figure 3 is a flowchart of a method for manufacturing a communication cable according to an embodiment of the present invention. [Modes for carrying out the invention]

[0010] The following describes a communication cable according to an embodiment of the present invention. However, the communication cable of the present invention is not limited to the embodiments shown below. In this specification, the "~" indicating a numerical range includes both an upper limit and a lower limit.

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

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

[0013] The communication cable 10 consists of multiple stranded wires 20 and intervening 30 twisted together in a predetermined twisting pitch in a specific direction. Here, "twisting pitch" refers to the distance in the longitudinal direction of the intervening 30 or the communication cable 10 when tracing one pair of stranded wires 20 from the multiple pairs of stranded wires 20 that are twisted together to form a spiral, and completing one rotation around the spiral axis. The number of stranded wires 20 is not particularly limited as long as there are multiple pairs. In this embodiment, the number of stranded wires 20 is four.

[0014] The collective twist pitch is greater than 20 mm and less than 80 mm. When the collective twist pitch is 20 mm or less, the length of the insulated wire 21 per 1 m of the communication cable 10 becomes long, resulting in poor conductor resistance. When the collective twist pitch is 80 mm or more, the pitch is unstable (the variation becomes large), and the internal structure within the communication cable 10 is unstable, resulting in poor near-end crosstalk attenuation.

[0015] Each of the plurality of twisted pairs 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" means the distance in the length direction of the twisted pair 20 required for one of the insulated wires 21 to make one turn when the 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 wire formed of a conductive metal material. The type of the conductor 22 is not particularly limited as long as it is formed of a conductive metal material. The conductor  22 may be a single wire or a stranded wire formed by twisting a plurality of wires together. In the present embodiment, the conductor 22 is a stranded wire formed by twisting a plurality of soft copper wires so as to have a predetermined twist pitch. Here, the "twist pitch" means the distance in the length direction of the conductor 22 required for any one of the soft copper wires to make one turn when the plurality of soft copper wires are twisted together.

[0018] The thickness of the conductor 22 (the diameter of the cross section orthogonal to the length direction) is not particularly limited. The thickness of the conductor 22 is appropriately selected according to the use and type of the communication cable 10. The diameter of the conductor 22 is, for example, within the range of 0.34 to 0.42 mm. In the present embodiment, the diameter of the conductor 22 is 0.34 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 this 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 is 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 is within a predetermined range. The thickness of the insulating layer 23 is preferably in the range of 0.10 to 0.30 mm, and more preferably in the range of 0.12 to 0.15 mm.

[0020] The intervening 30 isolates the multiple stranded wires 20 from each other. The intervening 30 extends in the longitudinal direction of the communication cable 10. The shape of the intervening 30 is not particularly limited as long as it can isolate the multiple stranded wires 20 from each other. In this embodiment, the cross-sectional shape of the intervening 30 perpendicular to the direction of extension is a plus sign shape. That is, in this embodiment, the intervening 30 is a cross-shaped intervening. The material of the intervening 30 is also not particularly limited as long as it can perform the above function. In this embodiment, the material of the intervening 30 is polyethylene. The intervening 30 is twisted together with the multiple stranded wires 20 along the longitudinal direction of the communication cable 10 at a predetermined twisting pitch.

[0021] The press-wound layer 40 covers the stranded wires 20 and the interlayer 30 inside the shielding layer 50. The press-wound layer 40 maintains a constant distance between the stranded wires 20 and the shielding layer 50. The press-wound layer 40 is wound or extruded over the stranded wires 20 and the interlayer 30. The thickness of the press-wound 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 press-wound 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 press-wound layer 40 is preferably in the range of 0.02 to 0.20 mm, and more preferably in the range of 0.02 to 0.06 mm.

[0022] The pressing layer 40 is made of a resin film. Examples of resin film materials include polyethylene terephthalate, polyester, polypropylene, polyethylene, nylon, aramid fibers, and acrylic fibers. In this specification, "resin film" is a concept that includes not only thin films of resin, but also nonwoven fabrics, woven fabrics, etc. In this embodiment, when the pressing layer 40 is made of a resin film, the material of the pressing layer 40 is polyethylene terephthalate tape or a polypropylene sheet. The number of pressing 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 around the paired wires 20 and the intervening 30. Here, "transverse winding" means winding the resin film spirally around the paired wires 20 and the intervening 30 such that a portion of the resin film overlaps.

[0023] The shielding layer 50 covers the winding layer 40 inside the outer sheath layer 60. The shielding layer 50 shields against external noise and other elements, and protects the multiple stranded wires 20 and the intervening 30. The shielding layer 50 is formed by winding a shielding tape horizontally over the winding layer 40. The shielding tape is a metal laminate tape. The shielding layer 50 (shielding tape) has a base layer 51 and a conductive layer 52. When the winding layer 40 is covered, the base layer 51 may be positioned inside the shielding layer 50, or the conductive layer 52 may be positioned inside the shielding layer 50. In this embodiment, the conductive layer 52 is positioned inside the shielding layer 50.

[0024] The material of the base layer 51 is not particularly limited as long as it has insulating properties. Examples of materials for the base layer 51 include various resins. Examples of resins include polyethylene terephthalate. The thickness of the base layer 51 is not particularly limited. The thickness of the base layer 51 is preferably in the range of 10 to 30 μm, and more preferably in the range of 12 to 25 μm. When the thickness of the base layer 51 is within this range, it becomes easier to wrap the shielding layer 50 around the winding layer 40.

[0025] The material of the conductive layer 52 is not particularly limited as long as it is a conductor. Examples of conductors include metals. Examples of metals include aluminum. The thickness of the conductive layer 52 is not particularly limited. The thickness of the conductive layer 52 is preferably in the range of 10 to 50 μm, and more preferably in the range of 20 to 40 μm. When the thickness of the conductive layer 52 is in this range, a sufficient shielding effect is more easily obtained. Also, when the thickness of the conductive layer 52 is in this range, it is easier to wrap the shielding layer 50 around the winding layer 40.

[0026] Figure 2A is a longitudinal cross-sectional view of the shielding layer 50 in the front-back direction, Figure 2B is a plan view of the shielding layer 50, and Figure 2C is a plan view of another modified example of the shielding layer 50. The conductive layer 52 of the shielding layer 50 (shielding tape) has a plurality of slits 53 formed therein that electrically divide the conductive layer 52. The arrangement of the plurality of slits 53 is not particularly limited as long as the above function is performed. The plurality of slits 53 may extend along the width direction of the conductive layer 52 and be arranged at predetermined intervals (Figures 2A, B), or they may extend along the width direction and length direction of the conductive layer 52 and be arranged in a matrix (Figures 2A, C). The plurality of slits 53 may also be arranged diagonally with respect to the length direction of the conductive layer 52. The width of each slit 53 is not particularly limited as long as the above function is performed. The width of each slit 53 is preferably in the range of 0.01 to 0.3 mm, and more preferably in the range of 0.02 to 0.25 mm. If the width of each slit 53 is within the specified range, it becomes easier to suppress the charging of the conductive layer 52 and to satisfy alien crosstalk. The spacing between multiple slits 53 is preferably within the range of 5 to 300 mm. If the spacing between multiple slits 53 is within the above range, the spacing between the slits 53 can be kept at an appropriate level when wound onto the pressing layer 40.

[0027] The width of the shielding layer 50 (shielding tape) is not particularly limited, but it is preferably in the range of 5 to 30 mm, and more preferably in the range of 15 to 25 mm. If the width of the shielding layer 50 (shielding tape) is less than 5 mm, it will take a long time to wrap. On the other hand, if the width of the shielding layer 50 (shielding tape) is more than 30 mm, it will be difficult to handle.

[0028] The outer layer 60 is made of resin and covers the conductive layer 52. The outer layer 60 protects the shielding layer 50. The outer layer 60 may be a single layer or multiple layers. In this embodiment, the outer layer 60 has a single-layer structure. The material of the outer layer 60 is resin and is not particularly limited as long as it can perform the above functions. Examples of materials for the outer layer 60 include polyvinyl chloride and flame-retardant polyethylene. In this embodiment, the material of the outer layer 60 is polyvinyl chloride. The thickness of the outer layer 60 is not particularly limited. The thickness of the outer layer 60 is, for example, in the range of 0.3 to 1.0 mm, and more preferably in the range of 0.3 to 0.5 mm. In this embodiment, the thickness of the outer layer 60 is, for example, 0.30 mm.

[0029] In the communication cable 10 according to this embodiment, the distance L between the conductor 22 and the shielding layer 50 is 0.150 mm or more and less than 0.230 mm, preferably 0.150 mm or more and 0.205 mm or less. 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 0.150 mm or more and less than 0.230 mm, preferably 0.150 mm or more and 0.205 mm or less.

[0030] Here, "the distance L between the conductor 22 and the shielding layer 50" is the shortest distance between the conductor 22 and the shielding layer 50 (see the double arrow in Figure 1). The distance L between the conductor 22 and the shielding layer 50 is measured at multiple points for each of the four stranded wires 20 (eight insulated wires 21). The measurement method is not particularly limited. For example, the communication cable 10 is cut at an arbitrary position in a direction perpendicular to its length, and the distance L is measured for each insulated wire 21.

[0031] Note that the distance L between the conductor 22 and the shielding layer 50 does not need to be satisfied for all insulated wires 21. For example, it is sufficient if more than half of the insulated wires 21 included in the communication cable 10 satisfy the condition. 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.

[0032] If the distance L between the conductor 22 and the shielding layer 50 is 0.150 mm or more and less than 0.230 mm (0.150 mm or more and 0.205 mm or less), the distance between the conductor 22 and the shielding layer 50 becomes appropriate, and the return loss requirements for Category 6A of the ANSI / TIA-568 standard can be met.

[0033] (Method of manufacturing communication cables) Figure 3 is a flowchart of the manufacturing method for the communication cable 10 according to Embodiment 1.

[0034] The communication cable 10 can be manufactured, for example, by the following method. Here, we describe a communication cable 10 having multiple stranded wires 20, an interlayer 30, a winding layer 40, a shielding layer 50, and an outer sheath layer 60.

[0035] As shown in Figure 3, the method for manufacturing the communication cable 10 includes the steps of preparing a plurality of twisted wire pairs 20 twisted in one direction at a predetermined twisting pitch (S110), forming a press-wound layer 40 (S120), forming a shielding layer 50 (S130), and forming an outer sheath layer 60 (S140).

[0036] In the step of preparing multiple stranded wires 20 (S110), first, the conductor 22 is covered with an insulating layer 23 to form an insulated wire 21. Next, multiple (in this case, two) insulated wires 21 are bundled together and twisted in one direction at a predetermined twisting pitch to form stranded wires 20. Then, intervening 30 are placed so that each stranded wire 20 does not come into contact with each other, and then each stranded wire 20 and intervening 30 are twisted together so that the combined twisting pitch is greater than 20 mm and less than 80 mm.

[0037] In the step of forming the press-wound layer 40 (S120), the press-wound layer 40 is formed on multiple stranded wires 20 and intervening 30. Specifically, the press-wound layer 40 is formed by horizontally winding polyethylene terephthalate tape or polypropylene tape while the wires are twisted in a certain direction at a predetermined twisting pitch. Alternatively, in this embodiment, the press-wound layer 40 is formed by extruding polyethylene terephthalate tape or polyethylene into a tube shape on multiple conductors 22 and intervening.

[0038] Here, the distance between the conductor 22 and the shielding layer 50 is adjusted to be between 0.150 mm and less than 0.230 mm.

[0039] In the step of forming the shielding layer 50 (S130), the shielding layer 50 is formed on top of the pressing layer 40. Specifically, a shielding tape with slits 53 formed in the conductive layer 52 is wound horizontally with the conductive layer 52 facing inward to form the shielding layer 50.

[0040] In the step of forming the outer sheath layer 60 (S140), the outer sheath layer 60 is formed on the outside of the pressing layer 40. 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 to obtain the communication cable 10.

[0041] (effect) As described above, according to the present invention, the distance between the conductor 22 and the shielding layer 50 including the slit is 0.150 mm or more and less than 0.230 mm, and the twisting pitch of the multiple stranded wires 20 is greater than 20 mm and less than 80 mm, so that the return loss, near-end crosstalk loss, and conductor resistance of the ANSI / TIA-568 standard Category 6A can be improved. [Examples]

[0042] The present invention will be described in more detail below with reference to examples. However, the scope of the present invention is not limited in any way by these examples, and the embodiments can be modified without departing from the spirit of the invention.

[0043] 1. Fabrication of communication cables (1) Fabrication of communication cable 1 Multiple soft copper wires (conductors) were extruded and coated with polyethylene to form an insulated wire having an insulating layer. Next, two insulated wires were twisted together to form a paired wire. Then, four paired wires were placed on a polyethylene cross-shaped separator and twisted together so that the bundled twisting pitch was 70 mm. A polyethylene terephthalate tape was then wrapped around the wire with a 1 / 2 overlap to a thickness of 0.040 mm (wound while overlapping by 1 / 2 of the tape width) to form a press-wound layer. Next, a 12 μm thick Al / PET tape was wrapped with a 1 / 2.5 overlap to form a shielding layer. Multiple slits were formed in the aluminum portion of the Al / PET tape at intervals of 30 mm along the width direction of the tape and at intervals of 7 mm along the length direction of the tape. Finally, a communication cable 1 of Example 1 was fabricated with a polyvinyl chloride extruded coating, having an outer sheath layer with a thickness of 0.30 mm. The distance between the conductor and the shielding layer of communication cable 1 was within the range of 0.210 mm to 0.225 mm.

[0044] (2) Preparation of communication cables 2-15 Except for the configuration of the communication cable shown in Table 1, communication cables 2 to 15 for Examples 2 to 11 and Comparative Examples 1 to 4 were manufactured in the same manner as communication cable 1 for Example 1.

[0045] 2. Evaluation (1) Evaluation of return loss For each communication cable wound to have an inner diameter of 120 mm, the return loss (RL) between 1 and 500 MHz was measured at 801 points using a network analyzer. The evaluation criteria for the return loss (RL) were determined as follows, according to the minimum range from the standard value described in "6. TRANSMISSION REQUIREMENTS" "6.4.6 Return loss (Category 6A)" of the ANSI / TIA-568.2-D standard. Evaluation Criteria ○: Minimum amplitude is 1.0 dB or higher △: Minimum range is between 0dB and less than 1.0dB ×: Minimum width is less than 0dB

[0046] (2) Evaluation of near-end crosstalk attenuation The near-end crosstalk attenuation was evaluated in accordance with ANSI / TIA-568-2.D standard "6.6.9 Horizontal cable NEXT Ioss". For each communication cable wound to a handle diameter of 120 mm, a network analyzer was used to measure 801 points for each pair between 1 and 500 MHz, and the minimum margin from the standard value below was determined. The near-end crosstalk attenuation was evaluated according to the following criteria. ○: Minimum margin is 2.0dB or higher △: Minimum margin is between 0dB and less than 2.0dB ×: Minimum margin is less than 0dB

[0047] (3) Evaluation of conductor resistance Conductor resistance was measured in accordance with ANSI / TIA-568-2.D standard "6.6.1 Horizontal cable dc resistance". Conductor resistance was evaluated according to the following criteria. ○:23.6Ω / 100m or less ×:23.6Ω / over 100m

[0048] (4) Evaluation of manufacturability Regarding manufacturability, we visually observed whether or not a winding restraint layer was formed. Manufacturability was evaluated according to the following criteria. ○: The retaining layer was wound correctly. ×: The retaining layer has broken.

[0049] (5) Overall evaluation The overall evaluation was based on the following criteria. ○: The evaluation result for (1) to (3) above was "○". △: One of the evaluation results from (1) to (3) above was "△". ×: Any of the evaluation results from (1) to (3) above were "×".

[0050] Table 1 shows the parameters of each communication cable that was fabricated, along with the evaluation results for each.

[0051] [Table 1]

[0052] As shown in Table 1, in the communication cables 1 to 11 of Examples 1 to 11, where the distance between the conductor and the shielding layer was 0.150 mm or more and less than 0.230 mm, the twisting pitch of multiple stranded wires was greater than 20 mm and less than 80 mm, and the shielding layer had slits formed in the conductive layer, the return loss, conductor resistance, and capacitance were all good. In particular, the communication cables 3 to 11 of Examples 3 to 11, in which the distance between the conductor and the shielding layer was 0.150 mm or more and 0.205 mm or less, showed even better reflection attenuation.

[0053] On the other hand, the communication cable 12 of Comparative Example 1, which had a twisted stranding pitch of 80 mm or more, exhibited poor near-end crosstalk attenuation. Furthermore, the communication cable 14 in Comparative Example 3, which had a twisted wire pitch of 20 mm or less, exhibited poor conductor resistance. This is thought to be due to the increased length of the insulated wire per meter of the communication cable. In Comparative Example 2, the communication cable 13, where the distance L between the conductor and the shielding layer was not within the range of 0.150 mm or more and less than 0.230 mm, exhibited poor return loss. The communication cable 15 of Comparative Example 4, in which the distance L between the conductor and the shielding layer was less than 0.150 mm, had poor manufacturability. This was because the push-wound layer broke during the cross-winding process. [Industrial applicability]

[0054] The communication cable according to the present invention is useful, for example, for high-speed communication LAN cables. [Explanation of Symbols]

[0055] 10 Communication Cables 20 stranded wires 21 Insulated wires 22 Conductors 23 Insulating layer 30 Intervention 40. Pressed layer 50 shielding layer 51 Base layer 52 Conductive layer 53 Slits 60 Outer layer

Claims

1. Multiple stranded wires, each having a conductor and an insulating layer covering the conductor, are twisted together in one direction. The aforementioned multiple stranded wires are covered by a pressing layer, A shielding layer covering the aforementioned winding layer, It has, The aforementioned shielding layer is The base layer, A conductive layer laminated on the aforementioned base layer, Includes, The distance between the conductor and the shielding layer is 0.150 mm or more and less than 0.230 mm. The combined twist pitch of the aforementioned multiple stranded wires is greater than 20 mm and less than 80 mm. The conductive layer has a plurality of slits formed therein that electrically divide the conductive layer. Communication cable.

2. A communication cable according to claim 1, The plurality of slits are characterized in that they are arranged at predetermined intervals or in a matrix. Communication cable.

3. A communication cable according to claim 1, The distance between the conductor and the shielding layer is characterized by being 0.150 mm or more and 0.205 mm or less. Communication cable.

4. A communication cable according to claim 1, The plurality of stranded wires are further characterized by having intervenes that separate them from one another. Communication cable.

5. A communication cable according to claim 1, It is further characterized by having an outer covering layer that covers the shielding layer, Communication cable.

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