JP6941286B2 - Communication cable and its manufacturing method - Google Patents

Description

The present invention relates to a communication cable such as a LAN cable and a method for manufacturing the same.

Conventionally, as a communication cable, a plurality of shielded core wires in which a shield tape is spirally wound around a pair of twisted wires are twisted together, and a sheath is provided so as to collectively cover the periphery thereof. As the shield tape, a tape having a metal layer formed on one surface of a resin layer is used.

In recent years, the communication speed has been increased. For example, in a LAN (Local Area Network) cable, a communication cable applicable to Category 7 or higher Category 7A or Category 8 conforming to ISO / IEC 11801 is required. ing. However, in the above-mentioned communication cable, a current flows through the end of the metal layer of the shield tape wound spirally to cause crosstalk, and the transmission characteristics such as the amount of crosstalk attenuation deteriorate especially in a high-speed signal. It was difficult to meet the standards. Therefore, a shielded core wire with a shield tape wound vertically has been proposed.

As prior art document information related to the invention of this application, there is Patent Document 1.

U.S. Pat. No. 2015/0996783

However, there are cases where sufficient transmission characteristics cannot be obtained simply by winding the shield tape vertically.

Therefore, an object of the present invention is to provide a communication cable having improved transmission characteristics when a high-speed signal is transmitted and a method for manufacturing the same.

An object of the present invention is to solve the above-mentioned problems, a core wire having an insulator that individually or collectively covers the periphery of one or more conductors, and a core wire that is vertically attached so as to cover the periphery of the core wire. A communication cable comprising a plurality of shielded core wires having a shield tape, and having a plurality of gaps between the plurality of shielded core wires adjacent to each other in the circumferential direction and the metal shield layer, wherein the plurality of shields are provided. Each of the attached core wires is one end in the width direction of the shield tape, and the end of the winding end side located outside the vertical winding is closer to the communication cable than the center position of the core wire. The shield tape is arranged so as to be radially outer, the other end in the width direction of the shield tape is located inside the vertical side winding, and the shield tape is located in the width direction of the shield tape. After facing one of the plurality of gaps from the end of the wire to the end of the winding end and facing the metal shield layer, the end of the shield tape on the winding end side becomes the one of the gaps. Provides communication cables that are wound to face different gaps.

According to the present invention, it is possible to provide a communication cable having improved transmission characteristics when a high-speed signal is transmitted and a method for manufacturing the same.

It is a figure which shows the communication cable which concerns on one Embodiment of this invention, (a) is the sectional view which shows the cross section perpendicular to the longitudinal direction, (b) is the perspective view which shows the end portion. It is sectional drawing of the shield tape. It is explanatory drawing explaining the direction of the crosstalk of a shielded core wire. (A) is a schematic configuration diagram of a twisting device used for manufacturing a communication cable, (b) is a schematic view of the tape winding portion, and (c) is a perspective view showing a die of the tape winding portion. It is sectional drawing which shows the arrangement of the die. It is a graph which shows the near-end crosstalk attenuation characteristic of the communication cable of an Example. (A) is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of the communication cable of the comparative example, and (b) is a graph showing the near-end crosstalk attenuation characteristic.

[Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1A and 1B are views showing a communication cable according to the present embodiment, FIG. 1A is a cross-sectional view showing a cross section perpendicular to the longitudinal direction thereof, and FIG. 1B is a perspective view showing an end portion thereof.

As shown in FIGS. 1A and 1B, the communication cable 1 includes one or more conductors 21 and a plurality of core wires 2 having an insulator 22 that individually or collectively covers the periphery of the conductors 21. , A metal shield that collectively covers the periphery of an aggregate 5 in which a shield tape 3 vertically wound around the core wire 2 and a plurality of shielded core wires 4 in which the core wire 2 is covered with the shield tape 3 are twisted together. A layer 6 and a sheath 7 that covers the periphery of the metal shield layer 6 are provided.

The communication cable 1 is used, for example, as a LAN cable for railway vehicles, a LAN cable for transmitting and receiving a large amount of data in a data center or the like.

In the present embodiment, the core wire 2 has a pair of insulated wires 23 in which one conductor (a stranded conductor obtained by twisting a plurality of metal strands 21a is twisted) 21 is covered with an insulator 22, and a pair of these. It is composed of a pair of twisted wires obtained by twisting an insulated wire 23. However, the present invention is not limited to this, and the core wire 2 may have, for example, a two-core batch coating structure in which a pair of conductors 21 arranged in parallel are collectively covered with an insulator 22, or one insulated wire 23. It may have only.

The conductor 21 is composed of a stranded conductor obtained by twisting a plurality of metal strands 21a. As the metal wire 21a, an annealed copper wire made of pure copper or an annealed copper wire made of pure copper plated with a metal such as tin or silver can be used. Not limited to this, the conductor 21 may be composed of a single wire conductor.

The insulator 22 has a foamed layer 221 made of a foamed resin that covers the periphery of the conductor 21, and a non-foamed layer 222 made of a non-foamed resin that covers the periphery of the foamed layer 221. As the foamed resin constituting the foamed layer 221, for example, foamed polyethylene can be used. Further, as the non-foaming resin constituting the non-foaming layer 222, for example, non-foaming polyethylene can be used. Not limited to this, the insulator 22 may be made of a material having a relative permittivity of 2.5 or less, for example, a fluororesin such as FEP (tetrafluoroethylene / hexafluoropropylene copolymer).

As shown in FIG. 2, the shield tape 3 has a resin layer 31 and a metal layer 32 formed on one surface of the resin layer 31. In the present embodiment, the resin layer 31 is made of polyester such as PET (polyethylene terephthalate). Further, the metal layer 32 is made of lightweight and low-cost aluminum. The shield tape 3 is vertically attached so as to individually cover the periphery of each of the plurality of core wires 2 with the metal layer 32 on the outside. Details such as how to wind the shield tape 3 will be described later.

The shielded core wire 4 is formed by vertically attaching a shield tape 3 around the core wire 2. Here, the case where four shielded core wires 4 are used will be described, but the number of shielded core wires 4 is not limited to this. In the present embodiment, four core wires 2, that is, four stranded wires are used, but it is desirable that the twist pitches of these four stranded wires are different from each other. This makes it possible to suppress the amount of crosstalk attenuation.

The four shielded core wires 4 are twisted together to form an aggregate 5. The aggregate 5 is twisted at a relatively long twist pitch, and the twist pitch is 70 mm or more and 140 mm or less. By setting the twist pitch of the aggregate 5 to 70 mm or more, the electrical length of the communication cable 1 can be shortened and the propagation delay time can be shortened, and the core wire 2 is tightened to prevent the foam layer 221 from being crushed for transmission. Deterioration of characteristics can be suppressed. Further, as will be described in detail later, in the present embodiment, since each shielded core wire 4 is twisted according to the twist of the aggregate 5, if the twist pitch of the aggregate 5 is short, the shield tape 3 There is a risk that the transmission characteristics will deteriorate due to wrinkles, etc., but by setting the twist pitch of the aggregate 5 to 70 mm or more, it is possible to suppress the occurrence of wrinkles on the shield tape 3 and deteriorate the transmission characteristics. Can be suppressed. Further, by setting the twist pitch of the aggregate 5 to 140 mm or less, it is possible to prevent the load from being concentrated on one shielded core wire 4 when the communication cable 1 is bent, resulting in deterioration of transmission characteristics and cable life. Shortening can be suppressed. Further, by twisting, the orientation and relative positional relationship of each shielded core wire 4 can be easily maintained, and the positional relationship between the winding end side end portions 3a, which will be described later, can be maintained.

By setting the twist pitch of the aggregate 5 to 70 mm or more and 140 mm or less in this way, stress on the shielded core wire 4 can be suppressed, and crushing of the foam layer 221 and wrinkling of the shield tape 3 can be suppressed. Deterioration of transmission characteristics due to bending can be suppressed, and the orientation and position of the end end 3a (described later) on the winding end side of the shield tape 3 of the shielded core wire 4 can be maintained. The twist pitch of the anti-twisted wire used as the core wire 2 is, for example, 14 mm or more and 20 mm or less. The twist pitch of the aggregate 5 is four times or more the twist pitch of the anti-twisted wire used as the core wire 2.

The metal shield layer 6 is formed so as to cover the periphery of the aggregate 5. The metal shield layer 6 and the metal layer 32 of the shield tape 3 in each shielded core wire 4 are in contact with each other and electrically connected to each other so as to have the same potential.

In the present embodiment, the metal shield layer 6 is composed of a braided shield in which a metal wire is braided. The metal shield layer 6 is less likely to tighten a member (here, an aggregate 5) located radially inward than the metal shield layer 6 as compared with, for example, a horizontal winding shield in which metal strands are arranged in a spiral shape. In the present embodiment, the inner diameter of the metal shield layer 6 is appropriately adjusted so that the aggregate 5 is not tightened. As a result, even when the insulator 22 includes the foam layer 221 it is suppressed that the foam layer 221 is crushed, and the deterioration of the transmission characteristics is suppressed. Further, the shielded core wire 4 can move relatively freely in the metal shield layer 6, and the communication cable 1 can be easily bent. Further, since a gap, that is, an air layer having a low relative permittivity is held between the shielded core wires 4, it is possible to further suppress the amount of attenuation. Although not shown in FIG. 1A, in reality, the cross-sectional shape of the shield tape 3 does not become circular because the shield tape 3 enters the gap between the shielded core wires 4.

In this embodiment, the sheath 7 is made of polyolefin. Further, as the sheath 7, one made of polyvinyl chloride (PVC) or fluororesin may be used. When flame retardancy is required, it is effective to use a sheath 7 made of ethylene vinyl acetate copolymer (EVA). Further, a metal hydroxide such as aluminum hydroxide or magnesium hydroxide may be added to the sheath 7 as a flame retardant by 100 parts by mass or more and 250 parts by mass or less with respect to 100 parts by mass of the base resin. Further, acid-modified polyolefin or the like may be added to the sheath 7. The sheath 7 may be formed by tube extrusion so as not to tighten the assembly 5. The outer diameter of the sheath 7, that is, the outer diameter of the communication cable 1, is, for example, 8.8 mm.

(Details such as how to wrap the shield tape 3)
As a result of studies by the present inventors, when the shield tape 3 is spirally wound around the core wire 2 (paired wire), the resin layer 31 is periodically arranged in the longitudinal direction of the cable. Therefore, when a high-speed signal is transmitted, crosstalk occurs in all directions in the circumferential direction from the resin layer 31. On the other hand, when the shield tape 3 is vertically attached and wound as in the present embodiment, as shown in FIG. 3, it is one end of the shield tape 3 in the width direction when a high-speed signal is transmitted. Moreover, it was found that crosstalk occurs from the end portion on the side located outside the vertical winding (hereinafter, referred to as the winding end side end portion 3a). Therefore, the amount of crosstalk attenuation can be suppressed by sufficiently separating the winding end side ends 3a of the shield tape 3 in each shielded core wire 4 from each other.

Therefore, in the present embodiment, each of the plurality of shielded core wires 4 is arranged so that the end portion 3a on the winding end side of the shield tape 3 is radially outside the center position (center axis) of the core wire 2. Placed. That is, as shown in FIG. 1A, each shielded core wire 4 is arranged so that the end end portion 3a at the end of winding is arranged outside the circle A passing through the center positions of the four core wires 2. bottom. As a result, in each shielded core wire 4, the winding end side end portion 3a is arranged radially inside the center position (circle A) of the core wire 2, which is the winding position where the crosstalk occurs. It is possible to separate the end side ends 3a from each other, suppress the amount of crosstalk attenuation, and improve the transmission characteristics. When the communication cable 1 is actually manufactured, the positions of the core wires 2 may be displaced. In this case, in a cross-sectional view perpendicular to the longitudinal direction, the true position is centered on the center position of the communication cable 1 (cable center) and passes through the center position of the core wire 2 closest to the cable center among the four core wires 2. It is preferable that the end portion 3a on the winding end side is arranged outside the circle.

In order to further suppress the amount of crosstalk attenuation, it is more preferable to arrange the winding end side end portion 3a more radially outward, so that the winding end side end portion 3a is arranged radially outside the core wire 2. It is more desirable to arrange each shielded core wire 4 in the. That is, each of the shielded core wires 4 is wound with the shield tape 3 so that the end portion 3a on the winding end side is located radially outside the core wire 2 (diameterally outside in the communication cable 1). In the present embodiment, each shielded core wire 4 is arranged so that the winding end side end portion 3a of each shield tape 3 is radially outside the circle B circumscribing the four core wires 2. ing. When the communication cable 1 is actually manufactured, the positions of the core wires 2 may be displaced. In this case, in a cross-sectional view perpendicular to the longitudinal direction, from a perfect circle centered on the center position (cable center) of the communication cable 1 and circumscribing the core wire 2 closest to the cable center among the four core wires 2. It is preferable that the end portion 3a on the winding end side is arranged on the outer side of the cable.

It is preferable that the end ends 3a on the winding end side of the shield tape 3 of each shielded core wire 4 are separated from each other by 2.5 mm or more. This is because if the distance between the winding end side ends 3a of the shield tape 3 of each shielded core wire 4 (straight line distance in a cross-sectional view perpendicular to the longitudinal direction) is less than 2.5 mm, the amount of crosstalk attenuation increases. This is because the transmission characteristics may be deteriorated.

In the present embodiment, in each of the plurality of shielded core wires 4, the winding end side end portion 3a of the shield tape 3 is formed between the shielded core wires 4 adjacent to each other in the circumferential direction and the metal shield layer 6. It is arranged so as to face the gap C to be formed. In the communication cable 1, since four shielded core wires 4 are arranged in the circumferential direction, there are four gaps C, but the winding end side end 3a of the shield tape 3 of each shielded core wire 4 is each. They are arranged so as to face different gaps C.

Not limited to this, the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4 may face the metal shield layer 6. Further, from the viewpoint of reducing the amount of crosstalk attenuation, the winding end side end 3a of the shield tape 3 of each shielded core wire 4 becomes the winding end side end 3a of the shield tape 3 of the other shielded core wire 4. It is more desirable that the end portion 3a on the winding end side does not face the end portion 3a on the winding end side of the shield tape 3 of the other shielded core wire 4. Further, in the present embodiment, the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4 faces the metal shield layer 6 side located between the adjacent shielded core wires 4.

It is desirable that the end ends 3a on the winding end side of the shield tape 3 of each shielded core wire 4 are separated as much as possible, and it is desirable that they are arranged at substantially equal intervals in the circumferential direction. In other words, it is desirable that the end end 3a of the shield tape 3 of each shielded core wire 4 is arranged at a position substantially 90 degrees rotationally symmetric with respect to the center of the cable.

Each shielded core wire 4 is twisted according to the twist of the aggregate 5, and the relative positional relationship of the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4 is the position in the longitudinal direction. Regardless, the relationship is almost constant. Therefore, when the assembly 5 is visually inspected with the sheath 7 and the metal shield layer 6 removed, the winding end side end 3a of each of the four shielded core wires 4 is exposed to the outside. That is, each shielded core wire 4 is arranged so that the end portion 3a on the winding end side is visible from the outside.

Further, it is desirable that the winding direction of the shield tape 3 is the same for each of the plurality of shielded core wires 4. This is because the crosstalk enters the core wire 2 from the end end 3a on the winding end side. Therefore, if the shielded core wire 4 in which the winding direction of the shield tape 3 is opposite is included, the shielded tape 3 is adjacent to each other in the circumferential direction. This is because the end ends 3a on the winding end side of the shield tape 3 of the core wire 4 face each other in the circumferential direction, and the amount of crosstalk attenuation may increase. The winding direction of the shield tape 3 referred to here is the end portion opposite to the winding end side end portion 3a in the width direction of the shield tape 3 when viewed from one end of the shielded core wire 4. This is the direction in which the shield tape 3 rotates along the circumference of the core wire 2 from the winding end to the end portion 3a on the winding end side.

The shield tape 3 is wound around the core wire 2 so as to make 1.3 laps or more and 1.5 laps or less around the core wire 2. If the winding of the shield tape 3 is less than 1.3 laps around the core wire 2, the overlap length becomes too short, the overlap portion opens for some reason, and there is a risk that crosstalk will increase. Further, winding the shield tape 3 vertically around the core wire 2 so as to exceed 1.5 turns is difficult in manufacturing, increases the cost, and makes the communication cable 1 heavy. When the shield tape 3 is wound around the core wire 2 for 1.3 turns, the overlap length is about 23% of the width of the shield tape 3. Further, when the shield tape 3 is wound around the core wire 2 for 1.5 turns, the overlap length is about 33% of the width of the shield tape 3. Therefore, the overlap length of the shield tape 3 is preferably 23% or more and 33% or less of the width of the shield tape 3. Further, in the present embodiment, in each of the plurality of shielded core wires 4, the overlapping portion (the portion where the shield tape 3 is doubled) on which the shield tape 3 overlaps is the metal shield layer 6. It is arranged so as to face each other in the radial direction. That is, the overlapping portion of the shield tape 3 of the shielded core wire 4 is located not on the center side of the communication cable 1 but on the metal shield layer 6 side.

Further, the thickness of the metal layer 32 of the shield tape 3 is preferably 30 μm or more. This is because if the thickness of the metal layer 32 is less than 30 μm, it may be broken during manufacturing, and the shape of the shield tape 3 cannot be maintained in the state where the core wire 2 is wound (wound). This is because there is a risk that the end end 3a at the end of winding will open later). In the present embodiment, the thickness of the metal layer 32 is 38 μm, and the thickness of the resin layer 31 is 12 μm.

(Manufacturing method of communication cable 1)
When manufacturing the communication cable 1, first, the foamed layer 221 and the non-foamed layer 222 are simultaneously coated around the conductor 21 to form the insulated wire 23. Then, the aggregate 5 is formed by using the twisting device 40 shown in FIG. 4 (a). Specifically, a pair of drums 41 around which the insulated electric wire 23 is wound is set in the sending portion 42, and the insulated electric wire 23 is sent out from both drums 41 while rotating the pair of drums 41, thereby forming a pair of twisted wires. The core wire 2 is formed. Here, four delivery units 42 are provided. The four core wires 2 transmitted from the four transmission units 42 are introduced into the tape winding unit 43.

As shown in FIG. 4B, in the tape winding portion 43, the shield tape 3 sent out from the bobbin 43a is tensioned through the plurality of rollers 43b, and the core wire 2 sent out from the sending portion 42. Is sent to the dice 44 together. In FIG. 4B, the core line 2 is shown by a broken line. Further, in FIG. 4B, only the path of one bobbin 43a and one shield tape 3 is shown as a representative, but in reality, four bobbins 43a are shown so as to correspond to the four core wires 2. Is provided, and the shield tape 3 is sent from each bobbin 43a to the corresponding die 44 via the plurality of rollers 43b.

As shown in FIG. 4C, the die 44 has a cylindrical main body portion 441 and a tape guide 442 provided on the inlet side (introduction side of the shield tape 3 and the core wire 2) of the main body portion 441. Have. The tape guide 442 has a pair of guide grooves 442a that guide both ends of the shield tape 3 in the width direction, and the shield tape 3 is gradually passed by passing both ends of the shield tape 3 in the width direction through the guide grooves 442a. It is deformed into a cylindrical shape, and the shield tape 3 is vertically attached and wound around the core wire 2. By appropriately adjusting the mounting angle of the tape guide 442, the approach angle of the shield tape 3 to the main body portion 441 is kept constant at a desired angle, and the position of the end end portion 3a on the winding end side of the shield tape 3 is set to a desired position. Can be adjusted to. The mounting angle of the tape guide 442 referred to here means the mounting angle of the main body portion 441 in the circumferential direction.

More specifically, the arrangement of the tape guides 442 of each die 44 is arranged so as to be 90-degree rotationally symmetric as shown in FIG. In FIG. 5, each die 44 is represented by a cross section taken along the line CC in FIG. 4 (c). In the present embodiment, the core wire 2 is introduced into the die 44 in a state of facing the central portion in the width direction of the shield tape 3. Further, in the present embodiment, since the winding end side end portion 3a is arranged on the opposite side of the core wire 2 with respect to the position of the introduced shield tape 3, the shield tape 3 is inside and the core wire 2 is. The mounting angle of the tape guide 442 is adjusted so that it is on the outside. The dies 44 are arranged close to each other, and are fixed by a fixing ring (not shown) in a state where the mounting angle of the tape guide 442 is appropriately adjusted.

The four shielded core wires 4 derived from each die 44 are introduced into the cylindrical assembly guide 46, are bundled (assembled), and are sent to the winding unit 45. More specifically, the four shielded core wires 4 that have passed through the assembly guide 46 are rotated in the circumferential direction by the take-up portion 45 and twisted to form an aggregate 5, and the formed aggregate 5 is formed. Is sent to the take-up unit 45. If the four shielded core wires 4 are twisted together without using the gathering guide 46, it becomes difficult to control the position of the winding end side end portion 3a of the shield tape 3 of each shielded core wire 4. In the present embodiment, four shielded core wires 4 are assembled by the assembly guide 46 and then twisted to form an aggregate 5. The gathering guide 46 also plays a role of preventing the influence of rotation by the winding portion 45 from being transmitted to the die 44 side.

Returning to FIG. 4A, the winding unit 45 winds the drum 45a for winding the aggregate 5 and the four shielded core wires 4 on the drum 45a while rotating them in the circumferential direction at once. It has a rotation mechanism 45b and. The four shielded core wires 4 bundled by the gathering guide 46 of the tape winding portion 43 are rotated (twisted) in the circumferential direction by the rotating mechanism 45b, whereby the aggregate 5 is formed. As described above, since the gathering guide 46 is used, the shield tape 3 of each shielded core wire 4 is twisted while maintaining the relative positional relationship between the winding end side end portions 3a. The formed aggregate 5 is wound around the drum 45a by the rotation of the rotation mechanism 45b.

After that, a metal shield layer 6 made of a braided shield is formed around the aggregate 5 wound around the drum 45a, and a sheath 7 is formed around the metal shield layer 6 by extruding a tube to form a communication cable 1. can get.

(Crosstalk attenuation characteristic of communication cable 1)
As an example, the near-end crosstalk attenuation characteristic of the communication cable 1 according to the present embodiment was obtained by simulation. The obtained near-end crosstalk attenuation characteristics are shown in FIG. FIG. 6 also shows the standard values required for the category 7 LAN cable. As shown in FIG. 6, the communication cable 1 of the embodiment has a near-end crosstalk attenuation amount having a likelihood with respect to a standard value even for a high-speed signal of 100 MHz or more, and is an excellent crosstalk attenuation amount. It can be seen that the characteristics are obtained.

For comparison with the present embodiment, for the communication cable 60 of the comparative example as shown in FIG. 7A, the near-end crosstalk attenuation characteristic was obtained by simulation in the same manner as in the embodiment. In the communication cable 60 of the comparative example, the end portion 3a on the winding end side of the shield tape 3 of each shielded core wire 4 is arranged on the cable center side (diameterally inside the communication cable 1 from the center position of the core wire 2). Has the same structure as the communication cable 1 of the embodiment. The obtained near-end crosstalk attenuation characteristics are shown in FIG. 7 (b).

As can be seen by comparing FIG. 7B and FIG. 6, the communication cable 60 of the comparative example has a near-end crosstalk attenuation amount for a high-speed signal of 100 MHz or more as compared with the communication cable 1 of the embodiment. It can be seen that the number is increasing and the likelihood of the standard value is decreasing, although the standard value is satisfied.

(Actions and effects of embodiments)
As described above, in the communication cable 1 according to the present embodiment, each of the plurality of shielded core wires 4 is one end in the width direction of the vertically attached shield tape 3, and is vertically attached. The winding end side end portion 3a located on the outside of the auxiliary winding is arranged so as to be radially outside the communication cable 1 from the center position of the core wire 2.

As a result, the shield tape of each shielded core wire 4 is compared with the case where the end portion 3a on the winding end side of the shield tape 3 is arranged radially inside the communication cable 1 from the center position of the core wire 2. It is possible to secure a large distance between the end ends 3a on the winding end side of No. 3 and improve transmission characteristics such as a crosstalk attenuation amount when a high-speed signal such as 100 MHz or more is transmitted. As a result, according to the communication cable 1, it is possible to satisfy the characteristics required for a LAN cable of category 7 or higher (for example, category 7A or category 8).

(Summary of embodiments)
Next, the technical idea grasped from the above-described embodiment will be described with reference to the reference numerals and the like in the embodiment. However, the respective reference numerals and the like in the following description are not limited to the members and the like in which the components in the claims are specifically shown in the embodiment.

[1] A core wire (2) having an insulator (22) that individually or collectively covers the circumference of one or more conductors (21), and a vertical winding so as to cover the circumference of the core wire (2). In a communication cable (1) including a plurality of shielded core wires (4) having a shielded tape (3), each of the plurality of shielded core wires (4) has a width of the shield tape (3). The winding end side end (3a), which is one end in the direction and is located outside the vertical winding, is radially outside the communication cable (1) from the center position of the core wire (2). Communication cable (1) arranged so as to be.

[2] The communication cable (1) according to [1], wherein the end ends (3a) of the shield tape (3) of the plurality of shielded core wires (4) are separated by 2.5 mm or more. ).

[3] The communication cable (1) according to [1] or [2], wherein each of the plurality of shielded core wires (4) has the same winding direction of the shield tape (3).

[4] Each of the plurality of shielded core wires (4) is arranged so that the winding end side end portion (3a) of the shield tape (3) is radially outside the core wire (2). The communication cable (1) according to any one of [1] to [3].

[5] A metal shield layer (6) that collectively covers the periphery of the plurality of shielded core wires (4) is provided, and each of the plurality of shielded core wires (4) is attached to the shield tape (3). The winding end side end portion (3a) is arranged so as to face the gap (C) between the plurality of shielded core wires (4) adjacent to each other in the circumferential direction and the metal shield layer (6). The communication cable (1) according to any one of [1] to [4].

[6] The communication cable (1) according to any one of [1] to [5], wherein the twist pitch of the aggregate (5) is 70 mm or more and 140 mm or less.

[7] The shield tape (3) has a resin layer (31) and a metal layer (32) formed on one surface of the resin layer (31), and the metal of the shield tape (3). The communication cable (1) according to any one of [1] to [6], wherein the layer (32) is made of aluminum and the thickness of the metal layer (32) is 30 μm or more.

[8] A metal shield layer (6) that collectively covers the periphery of the plurality of shielded core wires (4) is provided, and the metal shield layer (6) is a braided shield in which metal strands are braided. The communication cable (1) according to any one of [1] to [7], wherein the insulator (22) of the core wire (2) includes a foam layer (221) made of a foamed resin.

[9] A core wire (2) having an insulator (22) that individually or collectively covers the circumference of one or more conductors (21), and a vertical winding so as to cover the circumference of the core wire (2). A method of manufacturing a communication cable (1) including a plurality of shielded core wires (4) having a shielded tape (3), and a pair of guides at both ends of the shielded tape (3) in the width direction. The core has a guide groove (442a), and both ends of the shield tape (3) in the width direction pass through the guide groove (442a) to gradually deform the shield tape (3) into a tubular shape. A plurality of dies (44) configured to form the shielded core wire (4) by vertically wrapping the shield tape (3) around the wire (2) are used, and the plurality of dies (44) are used. ), The plurality of shielded core wires (4) are collectively rotated in the circumferential direction to form an aggregate (5), and the mounting angles of the plurality of dies (44) are adjusted. By adjusting each of them, when the aggregate (5) is formed, it is one end in the width direction of the shield tape (3) in the plurality of shielded core wires (4) and is vertical. A method for manufacturing a communication cable, in which the end end portion (3a) located on the outside of the auxiliary winding is arranged so as to be radially outside the communication cable (1) from the center position of the core wire (2). ..

[10] The plurality of shielded core wires (4) derived from the plurality of dies (44) are introduced into the assembly guide (46) and assembled, and the plurality of the shielded core wires (46) are assembled by the assembly guide (46). The method for manufacturing a communication cable according to [9], wherein the aggregate (5) is formed by collectively rotating the shielded core wires (4) in the circumferential direction.

Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. It should also be noted that not all combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

The present invention can be appropriately modified and implemented without departing from the spirit of the present invention. For example, although not mentioned in the above embodiment, in the shielded core wire 4, the shield tape 3 may be wound in a plurality of layers by vertical attachment winding. For example, when the two-layer shield tape 3 is wound, the amount of crosstalk attenuation can be further suppressed by wrapping the first layer and the second layer in opposite directions. In this case, the end portion 3a on the winding end side of the shield tape 3 wound on the outermost side may be located radially outside the communication cable 1 from the center position of the core wire 2.

1 ... Communication cable 2 ... Core wire 21 ... Conductor 22 ... Insulator 221 ... Foam layer 222 ... Non-foam layer 23 ... Insulated wire 3 ... Shielding tape 3a ... Winding end side end 31 ... Resin layer 32 ... Metal layer 4 ... Shield With core wire 5 ... Aggregate 6 ... Metal shield layer 7 ... Sheath

Claims (7)

A plurality of shielded core wires having an insulator that covers the circumference of one or more conductors individually or collectively, and a shield tape that is vertically attached so as to cover the circumference of the core wires are provided. , A communication cable having a metal shield layer that covers the periphery of an aggregate obtained by twisting the plurality of shielded core wires, and a plurality of gaps between the plurality of shielded core wires adjacent to each other in the circumferential direction and the metal shield layer. And
Each of the plurality of shielded core wires is one end in the width direction of the shield tape, and the end of the winding end side located outside the vertical winding is located closer to the center position of the core wire. The communication cable is arranged so as to be radially outside, and the other end in the width direction of the shield tape is located inside the vertical winding.
In the width direction of the shield tape, the shield tape faces one of the plurality of gaps from the other end to the end-winding end, faces the metal shield layer, and then faces the metal shield layer. A communication cable in which the end end of the shield tape is wound so as to face a gap different from the one of the above gaps. The ends of the plurality of shielded core wires on the winding end side of the shield tape are separated by 2.5 mm or more.
The communication cable according to claim 1. Each of the plurality of shielded core wires has the same winding direction of the shield tape.
The communication cable according to claim 1 or 2. Each of the plurality of shielded core wires is arranged so that the end of the shield tape on the winding end side is radially outside the core wire.
The communication cable according to any one of claims 1 to 3. The twist pitch of the aggregate obtained by twisting the plurality of shielded core wires is 70 mm or more and 140 mm or less.
The communication cable according to any one of claims 1 to 4. The shield tape has a resin layer and a metal layer formed on one surface of the resin layer.
The metal layer of the shield tape is made of aluminum
The thickness of the metal layer is 30 μm or more.
The communication cable according to any one of claims 1 to 5. A metal shield layer that collectively covers the periphery of the plurality of shielded core wires is provided.
The metal shield layer is a braided shield in which a metal wire is braided.
The insulator of the core wire includes a foamed layer made of a foamed resin.
The communication cable according to any one of claims 1 to 6.

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