Method for producing multipair transmission cable and composite cable

Abstract

To realize a multipair transmission cable and a composite cable in which deterioration of the transmission characteristics is suppressed.SOLUTION: A method for producing a multi-pair transmission cable according to one embodiment is a producing method of a multi-pair transmission cable including a plurality of twisted pairs, each of which is formed by twisting a pair of electric wires at a first pitch, and includes a pair twisting step S1 for twisting the pair of electric wires in a first direction to produce a twisted pair, and a bunch twisting step S2 for twisting the plurality of twisted pairs produced in the pair twisting step S1 in the first direction to produce a cable assembly. In the pair twisting step S1, a pair of wires is twisted with a second pitch shorter than the first pitch. In the bunch twisting step S2, a plurality of twisted wires is twisted while twisting.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a cable. [Background technology]

[0002] A multi-pair transmission cable is known that includes multiple twisted pairs of wires and a sheath that covers the twisted pairs. Each twisted pair includes a pair of twisted electric wires, and is generally called a "twisted pair cable." In this specification, multiple twisted pairs of wires may be collectively referred to as a "cable assembly."

[0003] When manufacturing a cable assembly, multiple twisted pair wires are sometimes twisted together while adding twist backs (Patent Document 1). By twisting multiple twisted pair wires together while adding twist backs, distortion of each twisted pair wire is prevented, and the attenuation of the multi-pair transmission cable can be stabilized. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2011-514649 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, when manufacturing a multi-pair transmission cable that requires bending durability, it is preferable to match the twisting direction of each twisted pair (hereinafter referred to as the "pair twisting direction") with the twisting direction of multiple twisted pairs (hereinafter referred to as the "collective twisting direction").

[0006] If the pair twisting direction and the group twisting direction are different, when a twist is applied to the multi-pair transmission cable, a force that loosens the twist acts on either the twisted pair wires or the cable assembly, and a force that tightens the twist acts on the other, which can result in buckling of the multi-pair transmission cable.

[0007] However, when multiple twisted pairs are twisted in the same direction as the twisting direction while adding twists, a rotational force acts on each twisted pair in the opposite direction to the twisting direction, which may cause the twist pitch of each twisted pair (the twist pitch of a pair of electric wires) to stretch.

[0008] As a result, in cable assemblies and multi-pair transmission cables that include them, the twist pitch of each twisted pair becomes longer than the designed value, which may result in a deterioration in transmission characteristics, such as an increase in crosstalk.

[0009] The present inventors inspected a multi-pair transmission cable whose transmission characteristics did not satisfy the standard values, and obtained the results shown in Table 1. More specifically, they inspected a cable assembly of four-pair LAN (Local Area Network) cables whose transmission characteristics did not satisfy the Category 5e (Cat.5e) standard values, and obtained the results shown in Table 1. The inspected cable assembly was manufactured by twisting four twisted pairs in the same direction as the pair twisting direction, with twist backs added.

[0010] In this test, the twist pitch of each of the four twisted pairs (No. 1 to No. 4) that make up the cable assembly was measured at three different points (points a, b, and c), and the average value (mm) was calculated. Furthermore, the ratio of the calculated average value to the design value (mm) (average value / design value) was calculated as the elongation rate (%).

[0011] The design values ​​of the twist pitch of each twisted pair (No. 1 to No. 4) are intentionally shifted to prevent crosstalk.

[0012] [Table 1]

[0013] This test confirmed that the twist pitch of all twisted pairs had elongated. Furthermore, the average elongation rate of the twist pitch of the four twisted pairs was approximately 110%. [Means for solving the problem]

[0014] A method for manufacturing a multi-pair transmission cable according to one embodiment includes a plurality of twisted pairs, each of which is formed by twisting a pair of electric wires at a first pitch, and includes a pair twisting step of twisting the pair of electric wires in a first direction to manufacture the twisted pairs, and a group twisting step of twisting the plurality of twisted pairs manufactured by the pair twisting step in the first direction to manufacture a cable assembly. In the pair twisting step, the pair of electric wires are twisted at a second pitch that is shorter than the first pitch, and in the group twisting step, the plurality of twisted pairs are twisted while being twisted back.

[0015] A method for manufacturing a composite cable according to one embodiment is a method for manufacturing a composite cable in which multiple cables are collectively coated, and includes a multi-pair transmission cable manufacturing process for manufacturing a multi-pair transmission cable including multiple twisted pairs in which a pair of electric wires is twisted at a first pitch, a cable preparation process for preparing multiple cables including the multi-pair transmission cable manufactured by the multi-pair transmission cable manufacturing process, and a combining process for twisting the multiple cables prepared by the cable preparation process.The multi-pair transmission cable manufacturing process also includes a pair twisting process for twisting a pair of the electric wires in a first direction to manufacture the twisted pair, and a bunch twisting process for twisting the multiple twisted pairs manufactured by the pair twisting process in the first direction to manufacture a cable assembly.Furthermore, in the pair twisting process, the pair of electric wires are twisted at a second pitch shorter than the first pitch, the bunch twisting process twists the multiple twisted pairs while twisting them back, and the combining process twists the multiple cables in the first direction. [Effects of the Invention]

[0016] According to the present invention, a multi-pair transmission cable and a composite cable in which degradation of transmission characteristics is prevented or suppressed are realized. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of a composite cable according to an embodiment. [Figure 2] FIG. 2 is an enlarged cross-sectional view of the multi-pair transmission cable shown in FIG. [Figure 3] 3 is a process diagram showing an example of a method for manufacturing the multi-pair transmission cable shown in FIG. 2. [Figure 4] 2 is a process diagram showing an example of a method for manufacturing the composite cable shown in FIG. 1. [Figure 5] 10 is a diagram showing measurement results of the transmission characteristics (near-end crosstalk attenuation) of a multi-pair transmission cable according to an embodiment. FIG. [Figure 6] 1 is a diagram showing the transmission characteristics (power sum near-end crosstalk attenuation) of a multi-pair transmission cable according to an embodiment; DETAILED DESCRIPTION OF THE INVENTION

[0018] An embodiment of the present invention will be described below with reference to the drawings. In all drawings used to describe the embodiment, the same or substantially the same components and elements will be designated by the same reference numerals. Furthermore, as a general rule, components and elements that have already been described will not be described again.

[0019] <Composite cable overview> 1 is a cross-sectional view of a composite cable 100 according to this embodiment. The composite cable 100 includes a plurality of units including a multi-pair transmission cable 1.

[0020] More specifically, the composite cable 100 includes one multi-pair transmission cable 1, two multi-pair transmission cables 2, and three multi-core cables 3. The composite cable 100 further includes a tension member 4 and a sheath 5.

[0021] The multi-pair transmission cable 1 is a LAN cable that meets the Category 5e (Cat.5e) standard. Each multi-pair transmission cable 2 is a LAN cable that meets the Category 7 (Cat.7) standard. Each multi-core cable 3 is a 4-core LAN cable that meets the Category 5 (Cat.5) standard.

[0022] The multi-pair transmission cable 1, the multi-pair transmission cable 2, and the multi-core cable 3 are arranged around the tension member 4 and twisted in the same direction. The sheath 5 covers the multi-pair transmission cable 1, the multi-pair transmission cable 2, and the multi-core cable 3 collectively.

[0023] There are no particular limitations on the use of the composite cable 100. However, as will be described later, the composite cable 100 has excellent bending durability. Therefore, the composite cable 100 is suitable for use in situations where vibrations or movements are applied, and is suitable for use as a crossover wire (jumper wire) laid between railway cars, for example.

[0024] <Outline of multi-pair transmission cable> Fig. 2 is an enlarged cross-sectional view of the multi-pair transmission cable 1 shown in Fig. 1. The multi-pair transmission cable 1 has a cable assembly 20 made up of a plurality of twisted pair wires 10 that are twisted together.

[0025] More specifically, the multi-pair transmission cable 1 has a cable assembly 20 made up of four twisted pairs 11, 12, 13, and 14. In other words, the multi-pair transmission cable 1 is a four-pair transmission cable (four-pair LAN cable).

[0026] Around the cable assembly 20, a separator 30, a shielding tape 41, an outer conductor 42, and a holding tape layer 50 are provided in this order from the radially inner side to the radially outer side.

[0027] The multi-pair transmission cable 2 shown in FIG. 1 has substantially the same structure as the multi-pair transmission cable 1 shown in FIG.

[0028] <Twisted pair wire> Each twisted pair wire 10 is a twisted pair cable having a pair of twisted electric wires 15. Each electric wire 15 is an insulated electric wire having an inner conductor 16 and an insulator 17 that covers the inner conductor 16.

[0029] The pair of electric wires 15 constituting each twisted pair 10 is twisted in a first direction at a first pitch P1 (mm). In other words, each twisted pair 10 is composed of two electric wires 15 twisted in the first direction at the first pitch P1.

[0030] The first pitch P1 is a twist pitch design value (mm) that is preset to satisfy the transmission characteristics required for the multi-pair transmission cable 1. However, the first pitch P1 of each twisted pair wire 10 is set to a different value to prevent crosstalk.

[0031] Each pair of electric wires 15 is twisted counterclockwise in the cross section shown in Fig. 2. In the following description, the twisting direction of the pair of electric wires 15 in each twisted pair wire 10 may be referred to as the "twisting direction." In other words, the twisting direction in this embodiment is the first direction (leftward).

[0032] In this embodiment, the internal conductor 16 is made of a copper wire, and the insulator 17 is made of polyethylene.

[0033] <Cable assembly> The cable assembly 20 is a bundle of four twisted wire pairs 11, 12, 13, and 14. More specifically, the cable assembly 20 is configured by the four twisted wire pairs 11, 12, 13, and 14 twisted at a predetermined pitch. In the following description, the twist direction of the four twisted wire pairs 11, 12, 13, and 14 may be referred to as the "collective twist direction."

[0034] The four twisted wire pairs 11, 12, 13, and 14 constituting the cable assembly 20 are twisted in the same direction as the pair twisting direction. More specifically, the four twisted wire pairs 11, 12, 13, and 14 shown in Fig. 2 are twisted counterclockwise in the cross section shown in Fig. 2. In other words, the collective twisting direction in this embodiment is the first direction (leftward).

[0035] In this way, the pair twisting direction and the group twisting direction are the same in the multi-pair transmission cable 1 according to this embodiment. More specifically, the four twisted pairs 11, 12, 13, and 14 constituting the cable assembly 20 are twisted left-handed, and the pairs of wires 15 constituting each of the twisted pairs 11, 12, 13, and 14 are also twisted left-handed.

[0036] <Separator> The separator 30 is made of polyethylene and covers the cable assembly 20. In other words, the separator 30 is a covering layer that holds the four twisted wire pairs 11, 12, 13, and 14 together.

[0037] <Shield layer> As described above, the shielding tape 41 and the outer conductor 42 are provided around the cable assembly 20. The shielding tape 41 is a PET (Poly Ethylene Terephthalate) tape with a metal such as aluminum vapor-deposited on its surface. From another perspective, the shielding tape 41 is a laminate tape in which a metal film is laminated on one surface of a PET film.

[0038] The shielding tape 41 is wrapped around the separator 30 to cover the separator 30. More specifically, the shielding tape 41 is wrapped horizontally around the outer periphery of the separator 30. However, the shielding tape 41 may also be wrapped vertically.

[0039] The outer conductor 42 is formed in a cylindrical (sleeve-like or tubular) shape using a conducting wire such as a copper wire or a copper alloy wire, or a resin thread covered with a metal film, etc. The outer conductor 42 is placed over the shielding tape 41 to cover the shielding tape 41.

[0040] As a result, a double-layered shielding layer 40 is formed by the shielding tape 41 and the outer conductor 42. However, the shielding layer 40 may be formed by either the shielding tape 41 or the outer conductor 42. In other words, the shielding layer 40 may be a single layer or multiple layers.

[0041] Sheath The pressure tape layer 50 can be formed using a known pressure tape, for example, by wrapping a resin tape around the shielding layer 40. When using a cloth tape as the pressure tape, it is preferable to use a 1 / 2 wrap. This allows the resin composition forming the sheath to permeate the cloth tape, preventing a decrease in peelability. When using a resin tape as the pressure tape, for example, a PET (Poly Ethylene Terephthalate) tape or the like can be used.

[0042] The pressure tape layer 50 forms the outermost layer of the multi-pair transmission cable 1. From another perspective, the cable assembly 20 is covered by the pressure tape layer 50, and the separator 30 and the shielding layer 40 are interposed between the cable assembly 20 and the pressure tape layer 50.

[0043] <Manufacturing method for multi-pair transmission cable> Next, an example of a method for manufacturing the multi-pair transmission cable 1 having the above configuration will be described. Figure 3 is a process chart showing the method for manufacturing the multi-pair transmission cable 1.

[0044] <Twisting process> In the twisting step S1 shown in Fig. 3, the twisted pair wire 10 shown in Fig. 2 is manufactured. More specifically, in the twisting step S1, the pair of electric wires 15 is twisted in a first direction at a second pitch P2 (mm). In other words, the pair of electric wires 15 is twisted left at the second pitch P2.

[0045] Here, the second pitch P2 is set to a length shorter than the first pitch P1, which is a design value (second pitch P2<first pitch P1). More specifically, the second pitch P2 is set to a length that is 90% or less of the first pitch P1. In this embodiment, the second pitch P2 is set to a length that is 90% of the first pitch P1.

[0046] As described above, the first pitch P1 of each twisted pair 10 is different from one another. Therefore, the second pitch P2 used when manufacturing each twisted pair 10 is also different from one another. For example, the second pitch in the twisting step S1 for manufacturing twisted pair 11 is different from the second pitch in the twisting step S1 for manufacturing twisted pair 12.

[0047] <Collective twisting process> In the group twisting step S2 shown in Fig. 3, the cable assembly 20 shown in Fig. 2 is manufactured. More specifically, in the group twisting step S2, the four twisted pairs 10 (twisted pairs 11, 12, 13, and 14) manufactured in the pair twisting step S1 are twisted in a first direction (leftward) at a predetermined pitch. In other words, the four twisted pairs 11, 12, 13, and 14 are twisted in the same direction as the pair twisting direction.

[0048] As a result, when twisting is applied to the multi-pair transmission cable 1 or the composite cable 100 including the same, a force to loosen or tighten the twist is selectively applied to both the twisted pairs 10 and the cable assembly 20. Therefore, buckling of the multi-pair transmission cable 1 is prevented or suppressed, and ultimately the bending durability of the composite cable 100 is improved.

[0049] Furthermore, in the group twisting step S2, the four twisted wire pairs 11, 12, 13, and 14 are twisted while being twisted back. Specifically, while the twisting machine that twists the four twisted wire pairs 11, 12, 13, and 14 makes one rotation, the bobbins that pay out each of the twisted wire pairs 11, 12, 13, and 14 are rotated in the direction opposite to the rotation direction of the twisting machine.

[0050] If the twist direction (collective twist direction) in the group twisting step S2 is the same as the twist direction (twist direction) in the pair twisting step S1, and a reverse twist is added, a force (rotational force / twist) in the opposite direction to the pair twisting direction is applied to the twisted pairs 11, 12, 13, and 14. As a result, there is a risk that the twist of the twisted pairs 11, 12, 13, and 14 will open up. In other words, there is a risk that the twist pitch of each twisted pair 11, 12, 13, and 14 will increase.

[0051] Therefore, in this embodiment, the twist pitch in the twisting step S1 is set in anticipation of the extension of the twist pitch in the group twisting step S2. Specifically, in the twisting step S1, twisting is performed at a second pitch P2 that corresponds to 90% of the design value (first pitch P1). In other words, the twist pitch (second pitch P2) in the twisting step S1 is 10% shorter than the design value (first pitch P1).

[0052] As a result, even if bunch twisting is performed in the same direction as the pair twisting direction while twisting back, the twist pitch of twisted pairs 11, 12, 13, 14 will not be longer than the design value (first pitch P1), or at least will not be significantly longer.

[0053] Rather, the twist pitch of twisted wire pairs 11, 12, 13, and 14 is adjusted to a design value (first pitch P1) by undergoing the bunch twisting step S2.

[0054] As mentioned above, the twist pitch of the twisted pair wires tested in the above test was found to be elongated by an average of about 10% from the design value.

[0055] <Separator coating process> In the separator covering step S3 shown in Fig. 3, the separator 30 shown in Fig. 2 is formed around the cable assembly 20 shown in the same figure. More specifically, in the separator covering step S3, a molten resin material is extruded around the cable assembly 20 to form a resin layer that covers the cable assembly 20.

[0056] <Shield layer formation process> 2 is formed. More specifically, in the shielding layer forming step S4 shown in Fig. 3, a shielding tape 41 is wrapped longitudinally around the separator 30 covering the cable assembly 20. Then, an outer conductor 42 is placed over the shielding tape 41.

[0057] <Coating process> In the covering step S5 shown in Fig. 3, the pressure tape layer 50 shown in Fig. 2 is formed. More specifically, in the covering step S5, the pressure tape is wound around the shielding layer 40 to form the pressure tape layer 50.

[0058] The multi-pair transmission cable 1 shown in FIGS. 1 and 2 is manufactured by a manufacturing method including the above steps.

[0059] <Composite cable manufacturing method> Next, a description will be given of an example of a method for manufacturing the composite cable 100 shown in Fig. 1. Fig. 4 is a process chart showing a method for manufacturing the composite cable 100.

[0060] <Manufacturing process for multi-pair transmission cables> In the multi-pair transmission cable manufacturing process S11 shown in Fig. 4, the steps shown in Fig. 3 are performed to manufacture the multi-pair transmission cable 1. In other words, the multi-pair transmission cable manufacturing process S11 shown in Fig. 4 includes the steps shown in Fig. 3.

[0061] <Cable preparation process> 4, a plurality of cables are prepared, including the multi-pair transmission cable 1 manufactured in the multi-pair transmission cable manufacturing process S11. More specifically, in the cable preparation process S12, the multi-pair transmission cables 1, 2, and multi-core cables 3 are prepared in the numbers shown in FIG.

[0062] ≪Composite process≫ In the combining step S13 shown in FIG. 4, the multi-pair transmission cable 1, the multi-pair transmission cable 2, and the multi-core cable 3 prepared in the cable preparation step S12 are twisted.

[0063] More specifically, the multi-pair transmission cable 1, the multi-pair transmission cable 2, and the multi-core cable 3 are twisted in a first direction around the tension member 4. That is, the twisting directions in the pair twisting step S1, the group twisting step S2, and the combining step S13 are all the first direction (leftward).

[0064] <Coating process> In the covering step S14 shown in Fig. 4, the sheath 5 shown in Fig. 1 is formed. More specifically, in the covering step S14, a molten resin material is pushed around the twisted multi-pair transmission cable 1, multi-pair transmission cable 2, and multi-core cable 3 to form a resin layer that covers them.

[0065] The composite cable 100 shown in FIG. 1 is manufactured by a manufacturing method including the above steps.

[0066] <Actions and Effects of the Present Embodiment> According to this embodiment, at least the following actions and effects can be obtained. (1) In the assembly twisting step S2, the plurality of twisted pairs 10 are twisted while twisting back. Therefore, no distortion that may cause abnormal attenuation or the like remains in each of the twisted pairs 10 that make up the cable assembly 20. (2) In the bunch twisting step S2, the multiple twisted pairs 10 are twisted in the same direction as the pair twisting direction. As a result, buckling of the multi-pair transmission cable 1 is prevented or suppressed, and the bending durability of the composite cable 100 is improved. (3) In the twisting step S1, which is performed before the group twisting step S2, twisting is performed at a second pitch P2 that is shorter than the design value (first pitch P1) in anticipation of the extension of the twist pitch in the group twisting step S2. As a result, even if the group twisting step S2, which is necessary to obtain the actions and effects of (1) and (2) above, is performed, the twist of each twisted pair 10 does not open.

[0067] The present inventors measured the transmission characteristics of the multi-pair transmission cable 1 according to this embodiment and obtained the measurement results shown in Fig. 5. In this measurement, the multi-pair transmission cable 1 according to this embodiment and another multi-pair transmission cable as a comparative example were prepared, and the near-end crosstalk attenuation of both was measured. Furthermore, when the power sum near-end crosstalk attenuation of an arbitrary pair of twisted pairs 10 was calculated based on the measurement results, the result shown in Fig. 6 was obtained.

[0068] The multi-pair transmission cable prepared as a comparative example is a multi-pair transmission cable having the same or substantially the same configuration as the multi-pair transmission cable 1 of this embodiment, except that it is manufactured by a manufacturing method in which the second pitch is the same as the first pitch.

[0069] From another perspective, the multi-pair transmission cable prepared as a comparative example is a multi-pair transmission cable manufactured by changing the twist pitch (second pitch P2) in the pair twisting process S1 shown in Figure 2 to be the same as the first pitch P1, which is the design value.

[0070] The measurement device used was the Vega 2004 DT manufactured by AESA Cortaillod, Inc. The measurement method used was in accordance with the IEC 61935-1 standard.

[0071] As a result of the measurements, the near-end crosstalk attenuation and the power sum near-end crosstalk attenuation of the multi-pair transmission cable 1 according to the present embodiment did not fall below the standard values. On the other hand, the near-end crosstalk attenuation and the power sum near-end crosstalk attenuation of the multi-pair transmission cable prepared as a comparative example fell below the standard values ​​in some bands.

[0072] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, the first direction is not limited to the left direction, but may be the right direction.

[0073] The cable assembly 20 shown in Fig. 2 may include an interposer (e.g., a cross interposer), in which case the twisted wire pairs 11, 12, 13, and 14 and the interposer are twisted together in the group twisting step S2 shown in Fig. 3.

[0074] The materials of the inner conductor 16 and the insulator 17 of the electric wire 15 can be changed as appropriate. The material of the pressure tape layer 50 can also be changed as appropriate.

[0075] When the multi-pair transmission cable 1 is used as one of the units that make up the composite cable 100 rather than as a single unit, the holding tape layer 50 may be omitted.

[0076] The units that make up the composite cable 100 are not limited to LAN cables. For example, the composite cable 100 may include signal lines and power lines instead of or in addition to the multi-pair transmission cable 2 and the multi-core cable 3. [Explanation of symbols]

[0077] 1, 2... multi-pair transmission cable, 3... multi-core cable, 4... tension member, 5... sheath, 10, 11, 12, 13, 14... paired wires, 15... electric wire, 16... inner conductor, 17... insulator, 20... cable assembly, 30... separator, 40... shielding layer, 41... shielding tape, 42... outer conductor, 50... holding tape layer, 100... composite cable

Claims

1. A method for manufacturing a multi-pair transmission cable including a plurality of twisted pairs in which a pair of electric wires is twisted at a first pitch, comprising: a twisting step of twisting the pair of electric wires in a first direction to manufacture the twisted pair; a bunch twisting step of twisting the plurality of twisted pairs produced in the pair twisting step in the first direction to produce a cable assembly, In the twisting step, the pair of electric wires are twisted at a second pitch shorter than the first pitch, In the gathering twisting step, a plurality of twisted pairs are twisted together while being twisted back together.

2. 2. The method of claim 1, wherein the second pitch is less than or equal to 90% of the first pitch.

3. 2. The method for manufacturing a multi-pair transmission cable according to claim 1, wherein the assembly twisting step twists four of the twisted pairs to manufacture the cable assembly.

4. A method for manufacturing a composite cable in which a plurality of cables are collectively coated, comprising the steps of: a multi-pair transmission cable manufacturing process for manufacturing a multi-pair transmission cable including a plurality of twisted pairs in which a pair of electric wires is twisted at a first pitch; a cable preparation step of preparing a plurality of cables including the multi-pair transmission cable manufactured by the multi-pair transmission cable manufacturing step; a compounding step of twisting the plurality of cables prepared in the cable preparing step, the multi-pair transmission cable manufacturing process includes a pair twisting process of twisting a pair of the electric wires in a first direction to manufacture the twisted pair wires, and a bunch twisting process of twisting a plurality of the twisted pair wires manufactured in the pair twisting process in the first direction to manufacture a cable assembly, In the twisting step, the pair of electric wires are twisted at a second pitch shorter than the first pitch, In the bunch twisting step, a plurality of the twisted wire pairs are twisted together while being twisted back, In the combining step, a plurality of the cables are twisted in the first direction.

5. The method for manufacturing a composite cable according to claim 4, wherein the second pitch is 90% or less of the first pitch.

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