Communication cable and manufacturing method thereof

Abstract

The invention provides a communication cable corresponding to high-frequency data transmission and capable of realizing simplification of the internal structure of the cable and a manufacturing method of the communication cable. Disclosed is a communication cable (1) in which a plurality of insulated wires (12), each of which is obtained by covering a conductor (14) with an insulator (16), are twisted together. In a communication cable (1), an intervening cord (20) is interposed between insulated wires (12), and the insulated wires (12) are twisted at a pitch of 17.5 mm or less.

Description

This invention application is a divisional application of the invention patent application with international application number PCT / JP2021 / 002157, international application date January 22, 2021, application number 202180010702.6 entering the Chinese national phase, and name “Communication cable and its manufacturing method”. Technical Field

[0001] The present invention relates to a communication cable corresponding to high frequency data transmission. Background Art

[0002] In recent years, the high performance of information and communication equipment in automobiles and the multifunctionality of in-vehicle multimedia have been continuously developed. In the future, the advanced driver-assistance systems (ADAS) and autonomous driving will be the keywords, and further high performance and the increase of equipment will continue to develop. Such progress has brought about the increase in the capacity of information and communication, requiring high-frequency data transmission. However, there are some problems in high-frequency data transmission, such as suppressing intra-pair skew (difference in propagation delay time within a pair) and suppressing the nesting phenomenon in the high-frequency band (a sharp drop in the frequency characteristics of signal attenuation).

[0003] Patent Document 1 discloses a multi-core cable for solving the above-mentioned problem of high-frequency data transmission. In the technology of Patent Document 1, eight pairs of coaxial wires (11 to 18) are housed in a multi-core cable (1). The central conductor (21) of each coaxial wire 10 is covered by an insulator (22), and its periphery is covered by an outer conductor (23) and a shell (24). In the outer conductor, a metal fine wire (M) is wound laterally (spirally) around the insulator as an inner layer (23A), and a metal resin tape (T) is wound laterally around the inner layer as an outer layer (23B). In this technology, in particular, the winding directions of the metal thin wire and the metal resin tape are set to opposite directions, and the difference in their winding angles (angle θ3) is set within a certain range, thereby suppressing the shearing phenomenon (see paragraphs 0017-0027, Figure 1 -2. Example Figure 4 wait). Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent No. 6269718 Summary of the invention Technical problem to be solved by the invention

[0005] However, as described above, the wire pair of Patent Document 1 has an outer conductor disposed inside a coaxial wire and is composed of a metal thin wire and a metal resin tape, and the winding direction and the winding angle of the metal thin wire and the metal resin tape must be set. The technology of Patent Document 1, that is, the internal structure of the cable is very complicated, and there is room for improvement in the internal structure of the cable. Therefore, the main purpose of the present invention is to provide a communication cable corresponding to high-frequency data transmission and to simplify the internal structure of the cable. Technical means for solving technical problems

[0006] In order to solve the above problems, according to the present invention, a communication cable is provided. A communication cable obtained by twisting a plurality of insulated electric wires having conductors covered with an insulator, characterized in that: An intervening rope is interposed between the insulated wires. The insulated electric wires are twisted at a pitch of 17.5 mm or less. Effects of the Invention

[0007] According to the present invention, (i) due to the provision of an intervening rope, the intra-pair skew is kept below 10 ps / m, and the transmission state is stable. (ii) each insulated wire is twisted at a pitch of 17.5 mm or less, so that the insertion loss (IL) does not drop (decrease) to 6 GHz, thereby suppressing signal attenuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a cross-sectional view showing a schematic structure of the communication cable involved in Embodiment 1. Figure 2A This is a flowchart schematically showing the method for manufacturing the communication cable according to the first embodiment. Figure 2B It is a schematic diagram used to illustrate the piping method. Figure 2C This is a schematic diagram for explaining the pressure mode. Figure 3A This is a cross-sectional view showing a schematic structure of a communication cable according to Embodiment 2. Figure 3B This is a flowchart schematically showing a method for manufacturing a communication cable according to the second embodiment. Figure 4 This is a graph showing the relationship between the frequency and the insertion loss of sample 1. Figure 5 This is a graph showing the relationship between the frequency and the insertion loss of sample 2. Figure 6 Graph showing the relationship between the frequency and the insertion loss of sample 11. Figure 7 Graph showing the relationship between the frequency and the insertion loss of sample 12. Figure 8 Graph showing the relationship between the frequency and the insertion loss of sample 13. Fig. 9 Graph showing the relationship between the frequency and the insertion loss of sample 14. Fig.10 : is a graph showing the relationship between the frequency and the insertion loss of sample 15. Fig.11A : is a graph showing the relationship between the frequency and the insertion loss of sample 21. Fig. 11B This is a diagram comparatively showing the relationship between the frequency and the insertion loss of samples 11 and 21. DETAILED DESCRIPTION

[0009] Hereinafter, a communication cable according to a preferred embodiment of the present invention will be described. In the present specification, "to" indicating a numerical range means that the lower limit value and the upper limit value are included in the numerical range.

[0010] [Implementation Method 1] Figure 1 It is a cross-sectional view showing a schematic structure of the communication cable 1. like Figure 1 As shown, the communication cable 1 includes a quad-core twisted wire 10 , an intervening rope 20 , a first shield layer 30 , a second shield layer 40 , and a sheath 50 , which are sequentially wound around and cover the periphery of the quad-core twisted wire 10 .

[0011] The four-core twisted wire 10 is composed of four-core (4) insulated wires 12, and each insulated wire 12 has a structure in which the wires are twisted at a pitch of 7.0 mm to 17.5 mm, preferably 7.0 mm to 16 mm, more preferably 7.0 mm to 14 mm, and further preferably 10.0 mm to 14 mm.

[0012] The lower limit value and the upper limit value of the twist pitch of the insulated wire 12 are set from the following viewpoints. The lower limit is conceived from the perspective of whether the inward skew can be suppressed and the manufacturing can be stable. The actual lower limit is 7.0 mm, preferably 10.0 mm. The shorter the twist pitch of the insulated wire 12, the denser the twist becomes, and the balance of the twisting of the insulated wires 12 becomes unstable. As a result, the insulated wires 12 have different physical lengths (length deviations), making it difficult to suppress the inward skew. If the twist pitch of the insulated wire 12 is set to be narrower, the amount (length) of the insulated wire 12 used increases, which becomes disadvantageous in terms of manufacturing or cost. The above lower limit is also conceived from the perspective of whether the manufacturing can be achieved.

[0013] The upper limit is derived from the viewpoint of suppressing the shearing phenomenon at high frequencies (up to 6 GHz), and the upper limit is 17.5 mm. Generally, it is expressed as wavelength = wave speed / frequency, and the twist pitch is 1 / 2 of the wavelength. If the speed of light is set to 100, the speed of the signal transmitted within the cable pair is about 70% as a technical common sense (NVP: Nominal Velocity of Propagation). If the frequency is set to 6 GHz, the upper limit of the twist pitch is theoretically derived as follows. If the wavelength of the signal transmitted within the cable pair is synchronized with the twist pitch of the insulated wire 12 and resonates, shearing occurs. If the upper limit of the twist pitch of the insulated wire 12 exceeds 17.5 mm, a resonance point is formed at low frequencies (below 6 GHz), and shearing is likely to occur.

[0014] Upper limit of the twist pitch =(wavelength)×(1 / 2) =(speed of light × NVP / frequency) × (1 / 2) =300,000,000[m / s]×0.7 / 6[GHz]×1 / 2 = Approximately 17.5 [mm]

[0015] In the four-core twisted wire 10, the first type core 10A and the second type core 10B are used in pairs, and the third type core 10C and the fourth type core 10D are used in pairs. The four-core twisted wire 10 can be composed of a pair (two cores) of the first type core 10A and the second type core 10B, or can be composed of pairs of cores from the fifth type core to the sixth type core.

[0016] The insulated wire 12 is composed of a conductor 14 and an insulator 16 , and has a structure in which the outer periphery of the conductor 14 is covered with the insulator 16 . The conductor 14 has a structure in which a plurality of strands are twisted, and each strand is made of a conductive metal material. Each strand is preferably an annealed copper wire, and the outer periphery is coated with a plating layer (not shown) of tin, nickel, or silver. The outer diameter of the conductor 14 is preferably 0.45 to 0.50 mm. The insulator 16 is formed by extruding an insulating resin from a die of an extruder. The insulating resin is preferably cross-linked polyethylene (XLPE) or polypropylene. The thickness of the insulator 16 is preferably 0.15 to 0.35 mm.

[0017] The intervening cord 20 is disposed at the center of the quad wire 10 (four insulated electric wires 12). The intervening cord 20 is a linear member having a circular cross-sectional shape, and is provided so that the arrangement relationship of the insulated electric wires 12 is constant. The intervention rope 20 is preferably made of high-density polyethylene (HDPE). The intervention rope 20 can be made of nylon, polypropylene, polyethylene terephthalate, or the like. The diameter of the intervention cord 20 is preferably 0.3 to 0.5 mm.

[0018] The first shield layer 30 is formed by overlapping and winding a metal tape. The metal tape is a tape formed by laminating a metal foil and a resin tape, and is preferably formed by laminating an aluminum foil and a polyethylene terephthalate tape (PET tape). In the first shield layer 30, the metal foil is overlapped and wound so as to be exposed on the outer periphery. The thickness of the metal tape is preferably 0.03 to 0.06 mm. On the other hand, the second shield layer 40 is formed by winding a plurality of metal wires in a horizontal direction at a pitch or less. The second shield layer 40 may be formed by weaving a plurality of metal wires. Each of the metal wires is preferably a so-called tinned annealed copper wire (TA) in which a tin-plated layer is applied to a annealed copper wire. The outer diameter of the metal wire is preferably 2.9 to 3.1 mm.

[0019] The sheath 50 is a so-called outer shell layer, and is formed by extruding a sheath resin from a die of an extruder. The sheath resin is preferably made of polyvinyl chloride (PVC) or thermoplastic elastomer (TPE). The thickness of the sheath 50 is preferably 0.2 to 0.6 mm.

[0020] Next, refer to Figure 2A A method for manufacturing the communication cable 1 will be described.

[0021] First, a plurality of single wires are twisted to form the conductor 14, an insulating resin is extruded to cover the conductor 14, and the conductor 14 is irradiated with electron beams to be cross-linked to form the insulator 16, thereby manufacturing the insulated wire 12 (S1). Thereafter, with the high-density polyethylene insertion cord 20 disposed at the center, the four insulated electric wires 12 are twisted at a pitch of 17.5 mm or less (quadruple twisting, S2).

[0022] Thereafter, a metal tape is overlapped and wound around the quad twisted wire 10 to form the first shield layer 30 , and a plurality of metal wires are transversely wound to form the second shield layer 40 ( S3 ).

[0023] Finally, the second shield layer 40 is extruded and covered with a sheath resin to form the sheath 50 ( S4 ), whereby the communication cable 1 can be manufactured. The extrusion of the sheath resin can be done by either a pipeline or a pressure method. The pipe method is a method in which a joint is inserted from the die opening to the extrusion port, and the extrudate always passes through the center of the joint when passing through the die, and the molten resin is extruded in a pipe shape (cylindrical shape) (refer to Figure 2B ). According to the pipe method, even if the shape of the extruded body is irregular, the thickness of the sheath is constant and the extruded body will not be crushed. The pressure method is a method in which a joint is inserted from the opening of the die to the middle part, and the extrudate passes through the center of the joint and then passes through the inside of the die when the extrudate passes through the die. The molten resin is extruded while being pressed against the extrudate (see Figure 2C ). Depending on the pressure mode, the sheath resin is likely to be in close contact with the surface of the extruded body.

[0024] According to the above communication cable 1, (i) due to the installation of the insertion rope 20, the skew is less than 10ps / m, and the transmission state is stable. (ii) Each insulated wire 12 is twisted at a pitch of less than 17.5mm, so the insertion loss (IL) does not drop (decrease) to 6GHz, and the attenuation of the signal in the high frequency band is suppressed (refer to the following embodiments 1 and 2). According to the communication cable 1, by providing the intervening cord 20 and setting the twist pitch of each insulated wire 12 to a certain value or less, a communication cable that is compatible with high-frequency data transmission and can simplify the internal structure of the cable can be provided.

[0025] [Implementation Method 2] Embodiment 2 is the same as Embodiment 1 except for the following point.

[0026] like Figure 3A As shown, in the communication cable 2 , the quad-core twisted wire 10 is covered by a wrap 25 , the wrap 25 is covered by a first shielding layer 30 , and the wrap 25 is formed between the quad-core twisted wire 10 and the first shielding layer 30 .

[0027] The wrap 25 is formed by overlapping and winding a strip of polyethylene terephthalate (PET). The wrap 25 may be formed of a strip of nonwoven fabric. The thickness of the wrap 25 is preferably 0.02 to 0.5 mm.

[0028] The conductor distance between a pair of the first type core 10A and the second type core 10B (or a pair of the third type core 10C and the fourth type core 10D) is dc, and the shortest distance between the conductor 14 of the pair and the first shield layer 30 is ds. In this case, the dc / ds value is 2 or less. The relationship of dc / ds value being 2 or less may be satisfied in at least one of the pair of the first type core 10A and the second type core 10B and the pair of the third type core 10C and the fourth type core 10D, and preferably satisfied in both pairs.

[0029] Reference Figure 3B A method for manufacturing the communication cable 2 will be described.

[0030] After the step S2 of twisting the insulated wires 12 , polyethylene terephthalate tape (PET tape) is wrapped around the quad wires 10 to form a wrap 25 ( S5 ), and then a metal tape is wrapped around the wrap 25 to form the first shield layer 30 . In the method for manufacturing the communication cable 2, from step S1 of manufacturing the insulated wire 12 to step S3 of covering the insulated wire 12 with the first shield layer 30, it is important to set (design) the dc / ds value to 2 or less.

[0031] According to the above communication cable 2, a wrap 25 is intentionally formed between the four-core twisted wire 10 and the first shielding layer 30, a physical distance is ensured between the conductor 14 of the pair of wires of the first core 10A and the second core 10B and the first shielding layer 30, and the dc / ds value is set to less than 2. According to this structure, the electromagnetic coupling between the pair of lines and the first shield layer 30 can be weakened, and attenuation of signals in a high frequency band can be suppressed (see Example 3 described below).

[0032] Furthermore, the communication cable 1 or the communication cable 2 may be used for any purpose as long as it is used for communication, but is preferably used for vehicle-mounted use, and more preferably for transmission of image or video signals of a vehicle-mounted camera. When the communication cable 1 or 2 is used in a vehicle and the characteristics are to be maintained for a long time, it is better to form the sheath 50 by the pressure method rather than the tube method. This is because the relationship between the components in the sheath 50 is fixed (maintained). [Example 1]

[0033] Here, the influence of the intervening rope in high-frequency data transmission is verified.

[0034] (1) Sample preparation (1.1) Sample 1 First, seven tinned soft copper wires with a diameter of 0.16 mm were twisted together to form a conductor with an outer diameter of 0.48 mm. Thereafter, the conductor was extruded and coated with polyethylene, and then irradiated with electron beams to be cross-linked, thereby forming an insulated electric wire having an outer diameter of 1.12 mm made of cross-linked polyethylene (XLPE). Then, with a high-density polyethylene insertion cord having a diameter of 0.45 mm disposed at the center, four insulated electric wires were twisted (quadruple twisted) at a pitch of 30 mm to form a quadruple twisted wire having an outer diameter of 2.70 mm.

[0035] Then, a metal tape obtained by laminating aluminum foil and polyethylene terephthalate tape (PET tape) was prepared as the first shield layer, and the metal tape was overlapped and wound around the quad-core twisted wire by 1 / 4 to form the first shield layer with an outer diameter of 2.82 mm. Then, 84 tinned annealed copper wires (TA) with a diameter of 0.1 mm were prepared as the second shield layer, and the tinned annealed copper wires were transversely wound around the first shield layer at a pitch of 32 mm or less to form the second shield layer with an outer diameter of 3.02 mm. Finally, polyvinyl chloride (PVC) is extruded and covered on the second shielding layer in a pipe manner to produce a communication cable with an outer diameter of 3.82 mm.

[0036] (1.2) Sample 2 The intervening rope was removed from Sample 1 and made into Sample 2.

[0037] (2) Sample evaluation Each sample was cut down to 5 m, and the intra-pair skew and the insertion loss in the high frequency band were measured. In Table 1 and Figure 4-5 The measurement results are shown in . The measurement results show the results for each pair of the first type core-the second type core, and the third type core-the fourth type core.

[0038] [Table 1]

[0039] (3) Summary As shown in Table 1, the intra-pair skew of sample 1 is much lower than 10 ps / m, whereas the intra-pair skew of sample 2 exceeds 10 ps / m. It can be seen that setting up an intervention rope helps stabilize the transmission state. However, the socketing phenomenon was observed in both samples 1 and 2 before the IL dropped to 6 GHz, and high-frequency data transmission could not be achieved with or without the intervention rope. [Example 2]

[0040] Here, the influence of the twist pitch of the quad-core twisted cable in high-frequency data transmission is verified.

[0041] (1) Sample preparation (1.1) Sample 11 In Sample 1 according to Example 1, four insulated electric wires were twisted (quadruple twist) at a pitch of 14 mm, and this was designated as Sample 11. Specifically, seven tinned annealed copper wires with a diameter of 0.16 mm were twisted together to form a conductor with an outer diameter of 0.48 mm. Thereafter, the conductor was extruded and coated with polyethylene, and then irradiated with electron beams to be cross-linked, thereby forming an insulated electric wire having an outer diameter of 1.12 mm made of cross-linked polyethylene (XLPE). Then, with a high-density polyethylene insertion cord having a diameter of 0.45 mm disposed at the center, four insulated electric wires were twisted (quadruple twisted) at a pitch of 14 mm to form a quadruple twisted wire having an outer diameter of 2.70 mm.

[0042] Then, a metal tape obtained by laminating aluminum foil and polyethylene terephthalate tape (PET tape) was prepared as the first shield layer, and the metal tape was overlapped and wound around the quad-core twisted wire by 1 / 4 to form the first shield layer with an outer diameter of 2.82 mm. Then, 84 tinned annealed copper wires (TA) with a diameter of 0.1 mm were prepared as the second shield layer, and the tinned annealed copper wires were transversely wound around the first shield layer at a pitch of 32 mm or less to form the second shield layer with an outer diameter of 3.02 mm. Finally, polyvinyl chloride (PVC) is extruded and covered on the second shielding layer in a pipe manner to produce a communication cable with an outer diameter of 3.82 mm.

[0043] (1.2) Sample 12 In Sample 11, the extrusion of the sheathing resin was changed to the “pressure method”, and this was designated as Sample 12.

[0044] (1.3) Samples 13-15 In Sample 11, the twist pitch of the insulated electric wire was changed to “18 mm”, and this was designated as Sample 13. In Sample 11, the twist pitch of the insulated wire was changed to “18 mm”, and the extrusion of the sheathing resin was changed to “pressure method”, which was designated as Sample 14. In Sample 11, the twist pitch of the insulated wire was changed to “60 mm”, and the extrusion of the sheathing resin was changed to “pressure method”, which was designated as Sample 15.

[0045] (2) Sample evaluation Each sample was cut down to 5 m, and the intra-pair skew and the insertion loss in the high frequency band were measured. In Table 2 and Figure 6 to Figure 10The measurement results are shown in . The measurement results show the results for each pair of the first type core-the second type core, and the third type core-the fourth type core.

[0046] [Table 2]

[0047] (3) Summary As shown in Table 2, samples 11-15 are all equipped with intervention ropes, the internal skew is below 10ps / m, and the transmission state is stable. For samples 11-12, no socketing phenomenon was observed before the IL passed 6 GHz. In contrast, for samples 13-15, socketing phenomenon was observed before the IL dropped to 6 GHz. It can be seen that twisting the insulated wires at a pitch of 17.5 mm or less with the intervening rope can help suppress the attenuation of signals in the high frequency band in addition to suppressing the internal skew. [Example 3]

[0048] (1) Sample preparation In Sample 1 according to Example 1, four insulated electric wires were twisted at a pitch of 14 mm (quadruple twist), and the four-core twisted wire was covered with a wrap to make Sample 21. Specifically, seven tinned annealed copper wires with a diameter of 0.16 mm were twisted together to form a conductor with an outer diameter of 0.48 mm. Thereafter, the conductor was extruded and coated with polyethylene, and then irradiated with electron beams to be cross-linked, thereby forming an insulated electric wire having an outer diameter of 0.88 mm made of cross-linked polyethylene (XLPE). Then, with a high-density polyethylene insertion cord having a diameter of 0.35 mm disposed at the center, four insulated electric wires were twisted (quadruple twisted) at a pitch of 14 mm to form a quadruple twisted wire having an outer diameter of 2.13 mm.

[0049] Thereafter, a polyethylene terephthalate tape (PET tape) having a thickness of 0.1 mm was prepared as a wrap, and the PET tape was wound around 1 / 2 of the four-core twisted wire in an overlapping manner to form a wrap having an outer diameter of 2.69 mm. Then, a metal tape obtained by laminating aluminum foil and polyethylene terephthalate tape (PET tape) was prepared as a first shield layer, and 1 / 4 of the metal tape was overlapped and wound around the wrap to form a first shield layer with an outer diameter of 2.81 mm. Then, 84 tinned annealed copper wires (TA) with a diameter of 0.1 mm were prepared as the second shield layer, and the tinned annealed copper wires were transversely wound around the first shield layer at a pitch of 32 mm or less to form the second shield layer with an outer diameter of 3.01 mm. Finally, polyvinyl chloride (PVC) is extruded and covered on the second shielding layer in a pipe manner to produce a communication cable with an outer diameter of 3.81 mm.

[0050] (2) Sample evaluation (2.1) Calculation of the distance between conductors dc and the shortest distance between conductor and shield ds The inter-conductor distance dc between the pair of wires of the first type core and the second type core in samples 11 and 21 and the shortest distance ds between the conductors of the pair of wires and the first shielding layer are calculated respectively.

[0051] In Sample 11, the values ​​of dc, ds, and dc / ds are as follows. dc = (insulated wire outer diameter 1.12mm - conductor outer diameter 0.48mm) + insertion rope diameter 0.45mm = 1.09mm ds = (insulated wire outer diameter 1.12mm - conductor outer diameter 0.48mm) × 1 / 2 = 0.32mm dc / ds value = 1.09 / 0.32 = 3.41

[0052] In sample 21, the values ​​of dc, ds, and dc / ds are as follows. dc = (insulated wire outer diameter 0.88mm - conductor outer diameter 0.48mm) + intervention rope diameter 0.35mm = 0.75mm ds = (insulated wire outer diameter 0.88mm - conductor outer diameter 0.48mm) × 1 / 2 + wrapping 1 / 2 overlap winding 0.28mm = 0.48mm DC / DS value = 0.75 / 0.48 = 1.56

[0053] (2.2) Determination of internal skew and insertion loss The sample 21 was cut down to 5 m, and the intra-pair skew and the insertion loss in the high frequency band were measured. The intra-pair skew is 2.10ps / m and 0.26ps / m. exist Fig.11A The measurement results of the insertion loss are shown in . The measurement results show the results for each pair of the first type core-the second type core, and the third type core-the fourth type core.

[0054] (3) Summary In sample 21, the internal skew is also below 10ps / m and the transmission state is stable, e.g. Fig.11A As shown, no socketing phenomenon is observed before the IL passes 6 GHz. like Fig. 11B As shown, if sample 11 is compared with sample 21, sample 21 has less insertion loss than sample 11. It can be seen that covering the four-core twisted wire with a wrap and setting the dc / ds value to 2 or less is particularly effective in suppressing the attenuation of signals in the high-frequency band. Industrial Applicability

[0055] The present invention relates to a communication cable and a method for manufacturing the same, and is particularly useful for providing a communication cable that is compatible with high-frequency data transmission and that can simplify the internal structure of the cable. Description of symbols

[0056] 1 Communication cable 2 Communication cables 10 Four-core twisted wire 10A~10D 1st~4th type wire core 12 Insulated wire 14 Conductor 16 Insulator 20 Intervention Rope 25 Wrapping 30 1st shielding layer 40 2nd shielding layer 50 sheath.

Claims

1. A communication cable, comprising: a wrap covering a plurality of said insulated wires; as well as A shielding layer covering the wrapping, An intervening rope is interposed between the insulated wires. The insulated wires are twisted at a pitch of 17.5 mm or less, The plurality of insulated wires are composed of one or more pairs, The distance between conductors of a pair of wires is dc, and the shortest distance between the conductors of the pair of wires and the shielding layer is ds. In this case, the dc / ds value is 2 or less.

2. The communication cable according to claim 1, characterized in that The insulated electric wires are twisted at a pitch of 14 mm or less.

3. The communication cable according to claim 1 or 2, characterized in that: For in-vehicle use.

4. A method for manufacturing a communication cable, characterized in that: include: The process of forming an insulated wire by covering a conductor with an insulator; The step of twisting the plurality of insulated wires at a pitch of 17.5 mm or less with the intervening rope arranged at the center; The step of covering the plurality of insulated wires with a wrap; and The step of covering the wrapping with a shielding layer, In the step of twisting the plurality of insulated wires, the plurality of insulated wires are formed into one or more pairs. In the process from forming the insulated wire to covering with the shielding layer, the distance between conductors of a pair of wires is dc, and the shortest distance between the conductors of the pair of wires and the shielding layer is ds. In this case, the dc / ds value is set to 2 or less.

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