Communication composite cable

Abstract

To provide a composite communication cable causing no return loss exceeding a predetermined reference value in each of communication cables.SOLUTION: A composite communication cable includes a plurality of communication cables twisted together and is laid between two rolling stocks. At least two of the plurality of communication cables include a plurality of twisted pair wires twisted together. Each of the twisted pair wires includes a plurality of insulated wires twisted together. The plurality of communication cables, the twisted pair wires, and the insulated wires have the same twist direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a composite cable, and more particularly to a communication composite cable having a plurality of communication cables. [Background technology]

[0002] A composite communication cable having a plurality of communication cables is known. One example of a conventional composite communication cable is a jumper cable for railway vehicles that includes two or more LAN (Local Area Network) cables with different transmission bands. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-188249 Summary of the Invention [Problem to be solved by the invention]

[0004] The present inventors have discovered that return loss in a communication composite cable generates values ​​(peak values) that exceed a predetermined reference value at certain frequencies. Based on this discovery, they conducted further research and found that no abnormalities were observed in the return loss of individual communication cables included in the communication composite cable. Specifically, when the return loss of multiple communication cables was measured individually before the communication composite cable was manufactured, no peak values ​​were observed. On the other hand, in a communication composite cable in which multiple communication cables that did not generate peak values ​​were twisted together, peak values ​​were observed in at least one or more of the communication cables.

[0005] Therefore, the inventors of the present invention have furthered their research to realize a communication composite cable in which no return loss exceeding a predetermined standard value occurs in any communication cable, and have completed the present invention.

[0006] An object of the present invention is to realize a communication composite cable in which no return loss exceeding a reference value occurs in any of the communication cables. [Means for solving the problem]

[0007] The composite communication cable of the present invention includes a plurality of twisted communication cables, at least two of which include a plurality of twisted pairs of wires, each of which includes a plurality of twisted insulated wires, and the twist directions of the plurality of communication cables, the twisted pairs, and the insulated wires are the same.

[0008] In one aspect of the present invention, a composite communication cable includes a tension member, five of the communication cables arranged around the tension member, and a filler arranged around the tension member and the communication cables.

[0009] In another aspect of the present invention, three of the five communication cables have a transmission band of 600 MHz, and two of the five communication cables have a transmission band of 100 MHz. [Effects of the Invention]

[0010] According to the present invention, a composite communication cable is realized in which no return loss exceeding a reference value occurs in any of the communication cables. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing an example of a communication composite cable of the present invention. [Figure 2] 2 is an explanatory diagram schematically showing the twist direction of the communication cables in the communication composite cable shown in FIG. 1. FIG. [Figure 3] 2 is an explanatory diagram schematically showing the twisting direction of the twisted pair wires and the insulated wires in the communication composite cable shown in FIG. 1.

[0023] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] An example of an embodiment of the composite communication cable of the present invention will be described below. The composite communication cable of this embodiment is a jumper cable installed across two railway cars. In the following description, the same reference numerals will be used in principle for identical or substantially identical configurations, elements, etc.

[0013] The jumper cable 1 shown in FIG. 1 includes a tension member 10, multiple communication cables 20, a filler 30, a pressure tape 40, and a sheath 50. The jumper cable 1 according to this embodiment includes five communication cables 20. In the following description, the five communication cables 20 shown in FIG. 1 may be distinguished by being referred to as "communication cable 20a," "communication cable 20b," "communication cable 20c," "communication cable 20d," and "communication cable 20e." In other words, the five communication cables 20 included in the jumper cable 1 may be distinguished by their reference symbols. However, this distinction is made merely for the sake of convenience.

[0014] The tension member 10 is disposed at the center of the jumper cable 1 and includes a high-tension wire 11 and an elastic intervening layer 12 provided around the high-tension wire 11. In this embodiment, the high-tension wire 11 is a plurality of twisted piano wires.

[0015] The elastic intervening layer 12 is formed of an elastomer. Specifically, the elastic intervening layer 12 is formed of a polyolefin-based elastomer. More specifically, the elastic intervening layer 12 is formed by extruding a polyolefin-based elastomer, which is a mixture of a polyolefin-based rubber such as ethylene propylene rubber and a resin such as polyethylene or polypropylene, around the high-tension wire 11.

[0016] The fillers 30 are arranged in the gaps between the tension members 10 and the communication cables 20 and in the gaps around the communication cables 20 so that the cross-sectional shape of the assembly of the tension members 10, the communication cables 20, and the fillers 30 is circular or approximately circular. The fillers 30 may be, for example, fibrous fillers or thread fillers made of plastic, jute, or the like.

[0017] 1 are twisted in the same direction at a predetermined twist pitch around the tension member 10. As a result, in the cross section of the jumper cable 1 (the cross section shown in FIG. 1), the communication cables 20a, 20b, 20c, 20d, and 20e are arranged around the tension member 10 in the circumferential direction of the tension member 10 at equal or approximately equal intervals.

[0018] As shown in Fig. 2, the twist direction of the communication cables 20a, 20b, 20c, 20d, and 20e of the jumper cable 1 is right-handed. In other words, the communication cables 20a, 20b, 20c, 20d, and 20e are all right-handed (S-twisted). In the following description, the twist direction of the communication cables 20 of the jumper cable 1 may be referred to as the "first twist direction." Note that hatching and other markings shown in Fig. 1 are omitted in Fig. 2.

[0019] Referring again to FIG. 1, of the five communication cables 20 shown in the figure, communication cables 20a, 20b, 20d, and 20e have the same basic structure. Specifically, communication cables 20a, 20b, 20d, and 20e each include four twisted pairs 21, an inner sheath 22, and a shielding layer 23 disposed around the twisted pairs 21. However, in communication cable 20a, the inner sheath 22 is disposed on the outside of the four twisted pairs 21, and the shielding layer 23 is disposed on the outside of the inner sheath 22. On the other hand, in communication cables 20b, 20d, and 20e, the shielding layer 23 is disposed on the outside of the four twisted pairs 21, and the inner sheath 22 is disposed on the outside of the shielding layer 23. Furthermore, shielding tape 27 is wrapped around each twisted pair 21 included in the communication cables 20b, 20d, and 20e, but shielding tape is not wrapped around each twisted pair 21 included in the communication cable 20a.

[0020] The four twisted pairs 21 included in the communication cables 20a, 20b, 20d, and 20e are twisted at a predetermined pitch, and the two insulated wires 24 constituting each twisted pair 21 are also twisted at a predetermined pitch. Each insulated wire 24 constituting each twisted pair 21 includes a conductor 25 and an insulating layer 26 provided around the conductor 25.

[0021] 1 includes four insulated wires 24 twisted at a predetermined pitch. Each insulated wire 24 includes a conductor 25 and an insulating layer 26 disposed around the conductor 25. A shielding layer 23 is disposed around the four insulated wires 24, and an inner sheath 22 is disposed around the shielding layer 23.

[0022] As shown in Fig. 3, the four twisted pairs 21 included in the communication cable 20a are right-handed (S-twisted). Although not shown, the four twisted pairs 21 included in the communication cables 20b, 20d, and 20e shown in Fig. 1 are also all right-handed (S-twisted). In the following description, the twist direction of the four twisted pairs 21 included in each of the communication cables 20a, 20b, 20d, and 20e may be referred to as a "second twist direction."

[0023] As shown in Fig. 3, the two insulated wires 24 constituting each twisted pair 21 in the communication cable 20a are all right-handed (S-twisted). Although not shown, the two insulated wires 24 constituting each twisted pair 21 in the communication cables 20b, 20d, and 20e shown in Fig. 1 are also all right-handed (S-twisted). In the following description, the twist direction of the two insulated wires 24 constituting the twisted pair 21 may be referred to as the "third twist direction." Note that hatching and other elements shown in Fig. 1 are omitted in Fig. 3.

[0024] The communication cables 20a and 20c shown in Fig. 1 have different transmission bands from the communication cables 20b, 20d, and 20e. Specifically, the communication cable 20a is a Category 5 LAN cable (0.5 mm² × 4P) with a transmission band of 100 MHz (compliant with IEC 61156-6). On the other hand, the communication cables 20b, 20d, and 20e are Category 7 LAN cables (AWG24 × 4P) with a transmission band of 600 MHz (compliant with IEC 61156-6). Furthermore, the communication cable 20c is a Category 5 LAN cable (0.5 mm² × 4C) with a transmission band of 100 MHz (compliant with IEC 61156-6). In other words, the jumper cable 1 is an Ethernet (registered trademark) type composite communication cable including two CAT5 LAN cables and three CAT7 LAN cables.

[0025] The thickness of the inner sheath 22 of each communication cable 20 is adjusted so that the outer diameters of the five communication cables 20 are the same or approximately the same. Here, the outer diameters of the five communication cables 20 being the same or approximately the same means that the difference between the outer diameter of each communication cable 20 and the average value of the outer diameters of the five communication cables 20 is within a range of ±0.5 mm.

[0026] The inner sheath 22 of each communication cable 20 is extruded from polyolefin resin. The outermost layer (inner sheath 22 or shielding layer 23) of each communication cable 20 contacts the elastic intervening layer 12 of the tension member 10.

[0027] As described above, the five communication cables 20a, 20b, 20c, 20d, and 20e included in the jumper cable 1 are right-handed (S-twisted). The four twisted pairs 21 included in each of the communication cables 20a, 20b, 20d, and 20e are also right-handed (S-twisted). Furthermore, the two insulated wires 24 included in each twisted pair 21 are also right-handed (S-twisted). Note that the communication cable 20c does not include a twisted pair 21. Therefore, the twist direction (second twist direction) of the twisted pairs 21 is not considered for the communication cable 20c.

[0028] As described above, the jumper cable 1 according to this embodiment has a plurality of communication cables 20. In the jumper cable 1 according to this embodiment, the three twist directions, namely the first twist direction, the second twist direction, and the third twist direction, are all unified in the same direction (rightward).

[0029] When the return loss of the communication cable 20 included in the jumper cable 1 of this embodiment having the above-described technical features was measured, no peak value exceeding a predetermined reference value was detected. Specifically, when the return loss was measured when an electrical signal of a predetermined frequency was transmitted using each of the communication cables 20 included in the jumper cable 1, no return loss exceeding the reference value was detected in any of the communication cables 20.

[0030] For comparison, a communication composite cable was prepared in which only the first twist direction was different from that of the jumper cable 1 of this embodiment, and similar measurements were performed. The prepared communication composite cable had the second and third twist directions "right" while the first twist direction was "left." As a result, a return loss exceeding the reference value was detected.

[0031] The reference value (dB) is a value calculated by the following formula (1) when the frequency of the transmitted electrical signal is f (MHz). 25-8.6log(f / 20) (however, 20≦f<600) (Formula 1) From the above measurement results, it was confirmed that the jumper cable 1 of this embodiment, in which the three twisting directions of the first twisting direction (twisting direction of the communication cable 20), the second twisting direction (twisting direction of the twisted pairs 21), and the third twisting direction (twisting direction of the insulated wires 24 constituting the twisted pairs 21) are the same, does not generate a return loss exceeding the reference value. Furthermore, from the above measurement results, it is inferred that in the jumper cable 1 of this embodiment, in which the three twisting directions of the first twisting direction, the second twisting direction, and the third twisting direction are the same, none of the twists of the communication cable 20, the twisted pairs 21, and the insulated wires 24 open, and therefore no abnormality in the return loss occurs.

[0032] 1 is a resin tape, and the shielding tape 27 is a PET tape with aluminum vapor deposition. The sheath 50 forming the outermost layer of the jumper cable 1 is made of a polyolefin elastomer.

[0033] The present invention is not limited to the above-described embodiment and can be modified in various ways without departing from the spirit of the present invention. For example, the communication cables included in the communication composite cable of the present invention are not limited to LAN cables. Furthermore, the number and types of communication cables can be modified as appropriate, provided that the following (1) and (2) are satisfied. (1) It contains at least two communications cables with two or more twisted pairs. (2) Each of the twisted pairs includes two or more twisted insulated wires.

[0034] Furthermore, it is sufficient that the three twist directions, i.e., the first twist direction, the second twist direction, and the third twist direction, are unified, and the direction may be right-handed (S twist) or left-handed (Z twist).

[0035] 1 can be replaced with a steel wire other than piano wire. The elastic intervening layer 12 can be made of a polyolefin-based elastomer having a composition different from that described above, and the elastic intervening layer 12 and the sheath 50 can also be made of a material other than a polyolefin-based elastomer. [Explanation of symbols]

[0036] 1 jumper cable 10 tension members 11 High-tension wire 12 Elastic intervening layer 20, 20a, 20b, 20c, 20d, 20e Communication cable 21 twisted pair wire 22 Inner sheath 23 Shielding layer 24 Insulated wire 25 Conductor 26 Insulating layer 27 Shielding tape 30 Intervention 40 Presser tape

Claims

1. A composite communication jumper cable having a plurality of twisted communication cables and laid across two railway cars, At least two of the plurality of communication cables include a plurality of twisted pairs; The communication cables include a Category 5 LAN cable and a Category 7 LAN cable, Each of the twisted pairs comprises a plurality of twisted insulated wires, The twist directions of the plurality of communication cables, twisted pair wires, and insulated wires are the same, A communication composite jumper cable that does not generate a return loss exceeding the reference value (dB) calculated by the following formula, when the frequency of the electrical signal being transmitted is f (MHz). 25-8.6log(f / 20) (however, 20≦f<600)...(formula)

2. 2. The communication composite jumper cable according to claim 1, Tension members and five of the communication cables arranged around the tension member; and a filler disposed around the tension member and the communication cable.

3. 3. The communication composite jumper cable according to claim 2, The five communication cables are three Category 7 LAN cables and five Category 5 LAN cables, forming a composite communication jumper cable.

Images