Cable

Abstract

To provide a cable which enables flex resistance thereof to be improved and enables good transmission characteristics to be obtained.SOLUTION: A cable 1 comprises: a cable core 5 having a linear filler 2 and a plurality of wire cores 3 for signal transmission; a shield layer 7 covering an area around the cable core 5; and a sheath 8 covering an area around the shield layer 7. The filler 2 is constituted of a first filler 21 provided at the cable center, and a plurality of second fillers 22 provided around the first filler 21 to form a cross-shape with the first filler 21 in a cross-sectional view perpendicular to a cable longitudinal direction. The cable core 5 is configured in such a manner that the plurality of wire cores 3 and the plurality of second fillers 22 are spirally twisted around the first filler 21 to be alternately arranged in a circumferential direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Examples of communication cables for signal transmission include LAN cables, coaxial cables, etc. In particular, Patent Document 1 proposes a twisted pair cable as a LAN cable, which includes a cross-shaped spacer having four partitions extending radially from the center, a twisted pair of wires arranged between the partitions of the cross-shaped spacer, and a shield layer and a sheath provided in that order on the outer periphery of the cross-shaped spacer and the twisted pair of wires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5457241 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for wiring signal transmission cables across moving or oscillating parts in industrial robots, etc. Signal transmission cables that are wired across moving or oscillating parts are required to have good transmission characteristics that satisfy standards such as Category 6A, as well as high bending resistance.

[0005] However, when the twisted pair cable using the above-mentioned cross-shaped insert is used as a cable to be wired to a movable or oscillating part, there is a problem that sufficient bending resistance cannot be obtained because the cross-shaped insert is difficult to bend and is easily broken when the cable is repeatedly bent. Furthermore, if the cross-shaped insert breaks, crosstalk occurs at the break point, increasing crosstalk between the twisted pairs (crosstalk between pairs), and the position of the twisted pairs becomes unstable, which may result in deterioration of transmission characteristics.

[0006] Therefore, an object of the present invention is to provide a cable that can improve bending resistance and obtain good transmission characteristics. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present invention provides a cable comprising a cable core having a linear interposer and multiple wire cores for signal transmission, a shielding layer covering the periphery of the cable core, and a sheath covering the periphery of the shielding layer, wherein the interposer is composed of a first interposer provided at the center of the cable and multiple second interposers provided around the first interposer so as to form a cross shape with the first interposer in a cross-sectional view perpendicular to the longitudinal direction of the cable, and the cable core is twisted spirally around the first interposer so that the multiple wire cores and the multiple second interposers are arranged alternately in the circumferential direction. Effect of the Invention

[0008] According to the present invention, it is possible to provide a cable that has improved bending resistance and provides good transmission characteristics. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to an embodiment of the present invention. [Diagram 2] 11 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to a modified example of the present invention. FIG. [Diagram 3] 11 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to a modified example of the present invention. FIG. [Figure 4] FIG. 1 is a diagram illustrating a bending resistance test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Embodiment Mode] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0011] 1 is a cross-sectional view showing a cross section perpendicular to the longitudinal direction of a cable according to the present embodiment. Cable 1 is a signal transmission cable (so-called LAN cable) that is wired across movable parts and swinging parts in industrial robots and the like. Cable 1 according to the present embodiment is a Category 6A LAN cable.

[0012] As shown in FIG. 1, the cable 1 includes a cable core 5 having a linear filler 2 and a plurality of wire cores 3 for signal transmission, a pressure winding tape 6 wrapped around the cable core 5, a shielding layer 7 arranged to cover the periphery of the pressure winding tape 6, and a sheath 8 covering the periphery of the shielding layer 7.

[0013] (wire core 3) In this embodiment, the wire core 3 is made of a twisted pair 30. The twisted pair 30 is used to transmit differential signals, and is formed by twisting a pair of insulated wires 31 together. In this embodiment, four twisted pairs 30 are used, and a total of eight insulated wires 31 are used. Note that the number of twisted pairs 30 (wire cores 3) used in the cable 1 is not limited to this. Furthermore, the wire core 3 may be, other than the twisted pair 30, a two-core parallel cable in which a pair of insulated wires 31 are arranged in parallel, or the like.

[0014] The insulated wire 31 constituting the twisted pair wire 30 has a conductor 311 and an insulator 312 covering the conductor 311. In order to increase durability against bending, it is preferable to use a stranded conductor formed by bundling a plurality of metal wires as the conductor 311. In this embodiment, a stranded conductor formed by twisting a plurality of metal wires made of tin-plated soft copper wires or the like having an outer diameter of 0.08 mm is used as the conductor 311.

[0015] In order to reduce the diameter of the cable 1, it is desirable to make the thickness of the insulator 312 as thin as possible. The thickness of the insulator 312 is preferably about 0.10 mm to 0.30 mm, for example. The outer diameter of the insulated electric wire 31 is preferably 0.6 mm to 1.0 mm, for example. In this embodiment, the insulator 312 is made of a thin fluororesin that can be extruded. Examples of the fluororesin used for the insulator 312 include FEP (perfluoroethylene propene copolymer) and PFA (perfluoroalkoxyalkane). In addition, the insulator 312 may be made of PE (polyethylene) or PP (polypropylene). In addition, when the insulator 312 is made of fluororesin made of FEP or PFA, friction is reduced (i.e., it becomes easier to slip) when the surface of the insulator 312 comes into contact with other members (insulators or insulators 312 of other insulated electric wires 31) when the cable is repeatedly bent, compared to when the insulator 312 is made of PE or PP. This allows the cable 1 to obtain high bending resistance.

[0016] Also, it is preferable that the insulator 312 is formed into a cylindrical shape by tube extrusion around the conductor 311. This allows the conductor 311 to move in the longitudinal direction of the insulated wire 31 within the insulator 312, making it difficult for the conductor 311 to break when the cable 1 is bent.

[0017] In each twisted pair 30, the twisting direction of the conductor 311 and the twisted pair 30 are opposite to each other. This is because, for example, if the twisting directions of the conductor 311 and the twisted pair 30 are the same, the twisted pair 30 will be twisted in a direction in which the twist of the conductor 311 is tightened, which increases the load on the metal wires included in the conductor 311 and may cause breakage when the cable 1 is bent. The twisting direction of the conductor 311 is the direction in which the metal wires rotate from the other end side to the one end side when viewed from one end of the insulated electric wire 31. The twisting direction of the twisted pair 30 is the direction in which the insulated electric wires 31 rotate from the other end side to the one end side when viewed from one end of the twisted pair 30.

[0018] In order to suppress crosstalk between the twisted pairs 30 (referred to as inter-pair crosstalk), it is preferable to set the twist pitch of each twisted pair 30 to be different from each other. The twist pitch of each twisted pair 30 may be different from each other within a range of 10 mm to 20 mm, for example, and it is preferable to set the difference in twist pitch of each twisted pair 30 to 2 mm or more. Note that the twist pitch of the twisted pair 30 is the interval along the longitudinal direction of the twisted pair 30 between points where any insulated electric wires 31 are at the same circumferential position in the circumferential direction of the twisted pair 30.

[0019] (Intervention 2) The interposer 2 is composed of one first interposer 21 and four second interposers 22, and in a cross-sectional view perpendicular to the cable longitudinal direction, the first interposer 21 and the second interposers 22 are arranged to form a cross shape.

[0020] The first intermediate portion 21 is provided at the center of the cable. The center of the cable is the part where stress is most likely to concentrate when the cable 1 is bent, and by arranging the first intermediate portion 21 at this center of the cable, the load applied to each twisted pair 30 when the cable 1 is repeatedly bent can be suppressed, breakage of the insulated wires 31 can be suppressed, and bending resistance can be improved.

[0021] The second intervening portion 22 plays a role of suppressing inter-pair crosstalk by separating the twisted pairs 30 (wire cores 3) from each other in the circumferential direction, and is disposed between the twisted pairs 30 adjacent in the circumferential direction. That is, in the cable 1, the twisted pairs 30 and the second intervening portion 22 are disposed alternately in the circumferential direction around the outer periphery of the first intervening portion 21. The outer diameter of the first intervening portion 21 is larger than that of the second intervening portion 22, and may be, for example, 1.5 to 1.7 times the outer diameter of the second intervening portion 22. This makes it possible to further improve the bending resistance of the cable 1 when the twisted pairs 30 and the second intervening portion 22 are disposed alternately. In this embodiment, the outer diameter of the first intervening portion 21 is set to 1.66 times the outer diameter of the second intervening portion 22. That is, the thickness of the first intervening portion 21 is larger than that of the second intervening portion 22, and the cross-sectional area of ​​the first intervening portion 21 perpendicular to the cable longitudinal direction is larger than that of the second intervening portion 22.

[0022] The outer diameter of the second intervening portion 22 is approximately equal to the outer diameter of the twisted pair wire 30 (core 3). More specifically, the outer diameter of the second intervening portion 22 is preferably 0.8 times or more and 1.0 times or less the outer diameter of the twisted pair wire 30 (core 3). By making the outer diameter of the second intervening portion 22 0.8 times or more the outer diameter of the twisted pair wire 30, even if the cable 1 is repeatedly bent, the twisted pair wires 30 adjacent to each other in the circumferential direction can be sufficiently separated to suppress inter-pair crosstalk. In order to further suppress inter-pair crosstalk, it is more preferable that the outer diameter of the second intervening portion 22 is 0.9 times or more the outer diameter of the twisted pair wire 30. In addition, if the outer diameter of the second intervening portion 22 is larger than the outer diameter of the twisted pair wire 30, the gap around the twisted pair wire 30 becomes large, making the arrangement of the twisted pair wire 30 unstable, and there is a risk of deteriorating transmission characteristics. Therefore, it is preferable that the outer diameter of the second intervening portion 22 is 1.0 times or less the outer diameter of the twisted pair wire 30. That is, by making the outer diameter of the second interposer 22 1.0 times or less the outer diameter of the twisted pairs 30, the arrangement of the twisted pairs 30 can be stabilized and the distance between the twisted pairs 30 can be easily kept constant even when the cable 1 is repeatedly bent, thereby suppressing deterioration of the transmission characteristics due to misalignment of the twisted pairs 30. Here, the outer diameter of the twisted pairs 30 is 1.28 mm, and the outer diameter of the second interposer 22 is 1.20 mm.

[0023] In this embodiment, four second interposers 22 are arranged at equal intervals around the first interposer 21, so that the first interposer 21 and the second interposer 22 are integrated to form a substantially cross-shaped interposer as a whole in a cross section perpendicular to the cable longitudinal direction. Conventionally, communication cables using one interposer whose cross section perpendicular to the cable longitudinal direction is cross-shaped have been known, but in such communication cables, the cross-shaped interposer makes the cable difficult to bend, and the cross-shaped interposer, which is difficult to bend, is easily broken when repeatedly bent. When the interposer breaks, crosstalk occurs at the break point, increasing crosstalk between pairs, and the position of the twisted pair wire 30 becomes unstable, deteriorating the transmission characteristics.

[0024] In contrast, in the present embodiment, a cross-shaped interposer 2 is formed by a first interposer 21 arranged at the center of the cable and a plurality of second interposers 22 arranged around the first interposer 21 separately from the first interposer 21, so that when the cable 1 is bent, the first interposer 21 and the second interposer 22 move relatively in the cable longitudinal direction, dispersing the stress caused by bending. As a result, even if the cable 1 is repeatedly bent, the first and second interposers 21, 22 are less likely to break, improving bending resistance, and making it possible to maintain good transmission characteristics by suppressing misalignment of the twisted pairs 30 and increases in inter-pair crosstalk.

[0025] Furthermore, in this embodiment, the multiple second intermediate portions 22 are provided so as to be capable of coming into contact with and being separated from the first intermediate portions 21 when the cable core 5 is bent. This makes it possible to further suppress breakage of the second intermediate portions 22 when the cable is bent, and further improve bending resistance.

[0026] It is desirable that the first intermediate portion 21 and the second intermediate portion 22 are made of a material whose surface is slippery and resistant to wear. It is also desirable that the first intermediate portion 21 and the second intermediate portion 22 are made of a material whose dielectric constant is as low as possible in order to suppress deterioration of the transmission characteristics. Examples of materials suitable for the first intermediate portion 21 and the second intermediate portion 22 that satisfy such characteristics include PE (polyethylene), fluororesin, and XF coated wire in which the resin surface is coated with XF (modified fluororesin).

[0027] Here, the first intervening portion 21 and the second intervening portion 22 are made of the same material in order to reduce manufacturing costs, but this is not limiting and the first intervening portion 21 and the second intervening portion 22 may be made of different materials. In this case, since the first intervening portion 21 disposed at the center of the cable receives a large load during bending, it is preferable that the tensile strength of the first intervening portion 21 is equal to or greater than the tensile strength of the second intervening portion 22.

[0028] In the present embodiment, the cross-sectional shape of the first interposer 21 and the second interposer 22 is circular (circular when no load is applied). The cross-sectional shape of the first interposer 21 and the second interposer 22 may be, for example, elliptical or polygonal. However, it is more desirable to make the cross-sectional shape of the first interposer 21 and the second interposer 22 circular from the viewpoints of aligning the cross-sectional shape with the outer shape of the twisted pair wire 30 to easily balance the entire cable, and reducing the contact area between the twisted pair wire 30 and the interposers 21 and 22 to easily move in the cable longitudinal direction when bent.

[0029] (Cable core 5) The cable core 5 is formed by twisting four twisted pairs 30 and four second intervenings 22 in a spiral shape around the first intervenings 21. At this time, the twisted pairs 30 and the second intervenings 22 are arranged alternately in the circumferential direction. The twisting direction of the cable core 5 is opposite to the twisting direction of the twisted pairs 30. In other words, the twisting direction of the cable core 5 is the same as the twisting direction of the conductor 311. The twisting direction of the cable core 5 is the direction in which the twisted pairs 30 and the second intervenings 22 rotate from the other end side to the one end side of the cable core 5 when viewed from one end of the cable core 5.

[0030] In this embodiment, the outer diameter of the second interposer 22 is smaller than that of the twisted pairs 30, so that the twisted pairs 30 are in direct contact with the outer surface of the first interposer 21 and the inner surface of the pressure winding tape 6. The second interposer 22 is provided so as to fill the gap between the circumferentially adjacent twisted pairs 30 and the inner surface of the pressure winding tape 6, and is in direct contact with the circumferentially adjacent twisted pairs 30 and the pressure winding tape 6, but is not in contact with the first interposer 21.

[0031] (Pressing tape 6) A pressure wrapping tape 6 is wound helically around the cable core 5. The pressure wrapping tape 6 serves to prevent the cable core 5 from untwisting, and to isolate the cable core 5 from the shielding layer 7. The pressure wrapping tape 6 is wound helically around the cable core 5 so that a part of the pressure wrapping tape 6 overlaps with the other tape in the width direction. In order to prevent the pressure wrapping tape 6 from damaging the shielding layer 7 when the cable 1 is repeatedly bent, it is desirable to use a pressure wrapping tape 6 that has as low rigidity as possible and a small restoring force (elastic force) that tries to return to a straight shape. For example, a paper tape or a nonwoven fabric tape may be used.

[0032] (Shield layer 7) The shield layer 7 is made of a braided shield formed by braiding a plurality of metal wires, and is provided so as to cover the periphery of the pressure wrapping tape 6. In this embodiment, the shield layer 7 has a two-layer structure made of a first shield layer 71 provided so as to cover the periphery of the pressure wrapping tape 6 and a second shield layer 72 provided so as to cover the periphery of the first shield layer 71, but the shield layer 7 may be a single layer.

[0033] In order to reduce the diameter and improve the flexibility of the cable 1, it is preferable to use metal wires with a small diameter of less than 0.10 mm for the first and second shield layers 71, 72. In this embodiment, metal wires made of soft copper wires with an outer diameter of 0.08 mm are used. The first and second shield layers 71, 72 may be a horizontally wound shield in which a plurality of metal braids are wound horizontally in a spiral shape. In addition, the metal wires constituting the first and second shield layers 71, 72 may be wires made of copper, aluminum or an alloy thereof, or wires having a metal layer made of metal foil or metal plating on the outer surface of the fiber thread.

[0034] (Sheath 8) The sheath 8 is provided so as to cover the periphery of the shield layer 7 (second shield layer 72). In this embodiment, the sheath 8 is made of polyvinyl chloride resin. However, the material of the sheath 8 is not limited to this, and it may be made of a resin composition having at least one type of resin, such as urethane resin, fluororesin, or fluororubber, as a main component (base). The thickness of the sheath 8 is 0.6 mm or more and 1.0 mm or less, and the outer diameter of the cable 1 is 6.0 mm or more and 9.0 mm or less. In this embodiment, the thickness of the sheath 8 is 0.8 mm, and the outer diameter of the cable 1 is 7.2 mm.

[0035] (Evaluation of transmission characteristics) A prototype cable 1 in FIG. 1 was produced, and inter-pair crosstalk (far-end crosstalk) and attenuation between each twisted pair 30 were measured. The cable length was 8 m, and inter-pair crosstalk and attenuation were measured using a network analyzer at frequencies from 1.0 MHz to 500.0 MHz in an environment of 20°C. Table 1 shows the inter-pair crosstalk measurement results and the Category 6A standard values. Table 2 shows the attenuation measurement results and the Category 6A standard values. In Tables 1 and 2, the four twisted pairs 30 are represented by A to D, respectively. For example, the column in Table 1 where the first row of the inter-pair crosstalk column is marked A and the second row is marked B represents inter-pair crosstalk between twisted pair A and twisted pair B.

[0036] [Table 1]

[0037] [Table 2]

[0038] As shown in Tables 1 and 2, cable 1 of this embodiment satisfies the Category 6A standard values ​​for both pair-to-pair crosstalk and attenuation in the frequency band of 1.0 MHz to 500.0 MHz, and it was confirmed that it has good transmission characteristics.

[0039] (Evaluation of bending resistance) Three cables 1 of FIG. 1 were fabricated, and a 90° left-right bending test was performed on each of the three fabricated cables 1 to evaluate their bending resistance. The 90° left-right bending test was performed by hanging a weight with a load W=2N (0.2 kgf) from the lower end of the sample cable 1, and bending jigs 100 curved on the left and right sides of the cable 1, and bending the cable 1 along the bending jigs 100 at a bending angle of ±90° in the left-right direction. The bending R (bending radius) was about twice the outer diameter (about 7.2 mm) of the cable 1. The bending speed was 30 times / min, and the number of bending times was counted as one round trip in the left-right direction. The cable 1 was repeatedly bent, and the conduction of the conductor 311 was checked between both ends of the cable 1 at each appropriate bending time. When the resistance value increased by 20% compared to the resistance value before the test (initial resistance value), it was considered that a break had occurred, and the number of bending times at that time was determined as the bending life.

[0040] A 90-degree left and right bending test was performed on the three manufactured cables 1 under strict conditions where the bending radius (bending radius) was about twice the outer diameter of the cable 1, and the results showed that the increase in resistance when the number of bending times reached 1 million was 0.1% to 3.4%. That is, the cable 1 according to the present embodiment hardly increased in resistance value of the conductor 311 even when the number of bending times reached 1 million (the increase in resistance value was 5% or less), and did not reach the end of its bending life.

[0041] (Modification) In the present embodiment, the first interposition 21 is described as being made of a single material, but the present invention is not limited thereto and the first interposition 21 may be made of a combination of a plurality of materials. For example, as in the cable 1a shown in FIG. 2, the first interposition 21 may have a tension member 21a and an insulating layer 21b that covers the periphery of the tension member. The tension member 21a may be, for example, a twisted steel wire or a high-tensile fiber. The first interposition 21 has the tension member 21a, which allows the tension member 21a to receive a tensile force during bending, and thus a high bending resistance that can suppress breakage can be realized even in applications where the cable is repeatedly bent violently or where the cable is strung.

[0042] 3, the first intermediate portion 21 may be formed by spirally winding a resin tape 21d around an insulating layer 21c having a circular cross section. For example, PTFE is an expensive material although it has good surface slipperiness, but by using an inexpensive resin such as PE for the insulating layer 21c and winding a resin tape 21d made of a material with good slipperiness such as PTFE around it, it is possible to realize the first intermediate portion 21 with a smooth surface while reducing costs, and thus to realize a low-cost cable 1b with good bending resistance.

[0043] (Functions and Effects of the Embodiments) As described above, the cable 1 of this embodiment comprises a linear first interlayer 21 provided at the center of the cable, a plurality of twisted pairs 30 formed by twisting a pair of insulated wires 31 together, a plurality of linear second interlayers 22 in the same number as the number of twisted pairs 30, a shielding layer 7 provided to cover the periphery of a cable core 5 formed by helically twisting the plurality of twisted pairs 30 and the plurality of second interlayers 22 around the first interlayer 21 so that the twisted pairs 30 and the second interlayers 22 are arranged alternately in the circumferential direction, and a sheath 8 covering the periphery of the shielding layer 7.

[0044] By separating adjacent twisted pairs 30 in the circumferential direction with the second interposer 22, it is possible to increase the distance between the pairs and suppress crosstalk between the pairs, thereby obtaining good transmission characteristics that satisfy the standard values ​​of Category 6A. Also, by configuring the first interposer 21 and the second interposer 22 separately, the second interposer 22 can move in the cable longitudinal direction relative to the first interposer 21, and the first interposer 21 and the second interposer 22 are less likely to break even if the cable 1 is repeatedly bent.

[0045] Furthermore, by setting the outer diameter of the second spacer 22 to be between 0.8 and 1.0 times the outer diameter of the twisted pair 30, it is possible to ensure the distance between the pairs and suppress inter-pair crosstalk, and to maintain the position of the twisted pair 30 (the positional relationship between the twisted pairs 30) constant even when the cable is bent, thereby achieving a cable 1 having high bending resistance that can withstand repeated bending millions to tens of millions of times, and having good transmission characteristics that fully satisfy the Category 6A standard values.

[0046] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0047] [1] A cable (1) comprising: a cable core (5) having a linear interposer (2) and a plurality of wire cores (3) for signal transmission; a shielding layer (7) covering the periphery of the cable core (5); and a sheath (8) covering the periphery of the shielding layer (7), wherein the interposer (2) is composed of a first interposer (21) provided at the center of the cable and a plurality of second interposers (22) provided around the first interposer (21) so as to form a cross shape with the first interposer (21) in a cross section perpendicular to the longitudinal direction of the cable, and the cable core (5) is twisted spirally around the first interposer (21) so that the plurality of wire cores (3) and the plurality of second interposers (22) are arranged alternately in the circumferential direction.

[0048] [2] The cable (1) described in [1], wherein the plurality of second intermediate members (22) are arranged so as to be capable of being brought into contact with and separated from the first intermediate members (21) when the cable core (5) is bent.

[0049] [3] The cable (1) according to [1] or [2], wherein an outer diameter of the first filler (21) is larger than an outer diameter of the second filler (22).

[0050] [4] The cable (1) according to any one of [1] to [3], wherein the outer diameter of the second filler (22) is 0.8 to 1.0 times the outer diameter of the wire core.

[0051] [5] The cable (1) according to any one of [1] to [4], wherein the tensile strength of the first filler (21) is equal to or greater than the tensile strength of the second filler (22).

[0052] [6] The cable according to any one of [1] to [4], wherein the wire core (3) is a twisted pair wire (30).

[0053] Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the embodiment described above. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention. [Explanation of symbols]

[0054] 1…Cable 2…intervention 21…First intervention 22…Second intervention 3…Wire core 30…Twisted pair 31…Insulated wire 5…Cable core 6…Press and wrap tape 7…Shield layer 8…Sheath

Claims

1. A cable core having a linear interposition and a plurality of wire cores for signal transmission; a shield layer covering the cable core; A sheath that covers the shield layer; a pressure winding tape between the cable core and the shield layer, the pressure winding tape being wound around the cable core; the intermediate portion is composed of a first intermediate portion provided at the center of the cable, and a plurality of second intermediate portions provided around the first intermediate portion so as to form a cross shape with the first intermediate portion in a cross section perpendicular to the longitudinal direction of the cable, the cable core is twisted around the first interposition in a spiral manner such that the plurality of wire cores and the plurality of second interpositions are alternately arranged in a circumferential direction, The outer diameter of the second intermediate portion is 0.8 times or more and less than 1.0 times the outer diameter of the wire core, The second intermediate portion is in direct contact with the wire core and the pressure winding tape adjacent to each other in the circumferential direction. cable.

2. The plurality of second intermediate portions are provided so as to be capable of coming into contact with and being separated from the first intermediate portions when the cable core is bent.

2. The cable of claim 1.

3. The outer diameter of the first intermediate portion is larger than the outer diameter of the second intermediate portion.

3. A cable according to claim 1 or 2.

4. The second intermediate portion is not in contact with the first intermediate portion. A cable according to any one of claims 1 to 3.

5. The tensile strength of the first intermediate is equal to or greater than the tensile strength of the second intermediate. A cable according to any one of claims 1 to 4.

6. The wire core is made of a twisted pair wire. A cable according to any one of the preceding claims.

Images