Communication cable

Abstract

Communication cable (1C), comprising: at least one signal line (10) comprising a pair of side-by-side insulated wires (11), each insulated wire (11) comprising a conductor (12) and an insulating sheath (13) enclosing the conductor (12); a shielding body (30) that encloses the at least one signal line (10); a casing (40) that encloses the shielding body (30) and has an outer shape with an approximately circular cross-section; and a high tensile strength fiber (50), where, if a direction along which the pair of insulated wires (11) is arranged side by side is defined as the lateral direction (a) and a direction which intersects the lateral direction is defined as the vertical direction (b), the high-tensile fiber (50) is arranged in the lateral direction (a) outside the at least one signal line (10) and runs along an axial direction of the at least one signal line (10), and the high tensile strength fiber (50) acts as a bending restriction element which restricts bending of the at least one signal line (10) in the lateral direction (a) compared to bending of the at least one signal line (10) in the vertical direction (b).

Description

TECHNICAL AREA

[0001] The present disclosure concerns communication cables. TECHNICAL BACKGROUND

[0002] In the field of high-speed communication, signal transmissions are carried out in a differential transmission mode, using communication cables known as twinaxial cables and shielded parallel pair cables. Fig. Figure 8 illustrates a typical example of the structure of such a conventional communication cable. A communication cable 9 has a signal line 90 with a pair of insulated wires 91, 92 running side by side. A shielding body is arranged at the outer edge of the signal line 90. The shielding body has a foil-like shield 92, such as a layered structure consisting of a metal strip and a braided shield 93. Furthermore, an outer sheath 94 made of an insulating plastic is arranged on the outer edge of the shielding body.

[0003] Recently, consideration has been given to using a communication cable with a signal line, which, as described above, has a pair of side-by-side insulated wires, in a vehicle such as an automobile. When using the communication cable in vehicles, for example, the requirement to route cabling in confined spaces or along a complex route often necessitates bending the communication cable.

[0004] If the signal conductor in a communication cable is bent, the bending can affect the cable's transmission characteristics, and therefore measures are proposed to minimize this effect. For example, JP 2015-210919A describes a twinaxial cable with a guide wire and a shielding strip. In this cable, the relative positions of two insulated wires and a guide wire are predetermined to achieve a smaller intrapair delay skew when bent.

[0005] US 6 803 518 B2 discloses a high-frequency transmission cable with a flat cross-section.

[0006] The CN 2 05 984 342 U reveals a bend-resistant, twisted, flexible, flat communication cable.

[0007] US patent 6,323,428 B1 discloses a structure for protecting a flexible ribbon cable. OVERVIEW OF THE INVENTION TASKS TO BE SOLVED BY THE INVENTION

[0008] As described above, it is important to minimize the impact of cable bending on the transmission characteristics of a communication cable, especially when the cable is used in a bent state in confined spaces such as inside a vehicle. In addition to minimizing the impact of bending, it is also crucial to prevent excessive strain on the signal line caused by excessive bending. If bending exerts a significant load on the signal line, this load can not only affect the transmission characteristics but also shorten the lifespan of the signal line.

[0009] As in Fig. As illustrated in Figure 8, in the communication cable 9 with the signal line 90, which comprises the side-by-side insulated wires 91, 91, a side-by-side direction of the insulated wires 91, 91 is referred to as lateral direction a, while a direction perpendicular to lateral direction a is referred to as vertical direction b. In this case, the communication cable 9 can be bent at an axially central section in vertical direction b without exerting a large load on the signal line 90 in vertical direction b. However, bending the communication cable 9 at an axially central section in lateral direction a does exert a large load on the signal line 90.

[0010] The present disclosure is based on the objective of providing a communication cable with a signal line having a pair of side-by-side insulated wires, which is suitable for reducing a load exerted on the signal line when the communication cable is bent laterally. MEANS OF SOLVING THE TASK

[0011] A communication cable according to the present disclosure is a communication cable according to one of the independent claims. EFFECT OF INVENTION

[0012] The communication cable according to the present disclosure includes the bending-limiting element, which restricts the bending of the signal conductor in the lateral direction compared to bending in the vertical direction. The bending-limiting element helps to prevent a large load from being exerted on the signal conductor of the communication cable due to bending in the lateral direction. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a perspective cross-sectional view illustrating a communication cable according to a first example. Fig. 2A and Fig. 2B are cross-sectional views of the communication cable. Fig. 2A illustrates a state without twisting. Fig. 2B illustrates a state with rotation and corresponds to the cross-section along line AA in Fig. 3B. Fig. 3A and Fig. 3B are views that explain the bending of the communication cable. Fig. 3A illustrates a state before bending. Fig. 3B illustrates a state after bending. Fig. 4A and Fig. 4B are cross-sectional views of a communication cable according to modified examples where multiple signal lines run side by side. Fig. Figure 4A illustrates a form that includes only a foil-shaped shield as the shielding body. Fig. Figure 4B illustrates a form that incorporates a combination of a braided shield and a foil-shaped shield as a shielding body. Fig. Figure 5 is a cross-sectional view of a communication cable according to a modified embodiment in which the insulating sheaths of a pair of insulated wires are formed in one piece. Fig. Figure 6 is a cross-sectional view of a communication cable according to a second embodiment of the present disclosure. Fig. Figure 7 is a cross-sectional view of a communication cable according to a third embodiment of the present disclosure. Fig. Figure 8 shows a cross-sectional view of a conventional communication cable. FORMS OF EXECUTION OF THE INVENTION: Description of exemplary configurations

[0013] First, exemplary configurations are listed and described.

[0014] A communication cable according to the present disclosure comprises: at least one signal line comprising a pair of insulated wires arranged side by side, each insulated wire comprising a conductor and an insulating sheath enclosing the conductor; a shielding body enclosing the at least one signal line; a jacket enclosing the shielding body; and a bending restriction element which restricts bending of the at least one signal line in a lateral direction along which the pair of insulated wires is arranged side by side, compared to bending of the at least one signal line in a vertical direction intersecting the lateral direction.

[0015] The communication cable incorporates a bending-limiting element that restricts lateral bending of the signal conductor compared to vertical bending. Because the signal conductor comprises a pair of insulated wires arranged side-by-side in the lateral direction, the load from lateral bending is expected to be greater than the load from vertical bending. However, the communication cable incorporates the bending-limiting element to restrict lateral bending of the signal conductor, thus preventing a large load from being exerted on the signal conductor due to lateral bending.

[0016] When an external force is applied to the communication cable, causing it to bend laterally, the bend-limiting element restricts this bending, and the external force is thus absorbed by twisting the communication cable. Alternatively, the bend-limiting element guides the bending direction so that the signal cable bends vertically rather than laterally. In this way, the presence of the bend-limiting element allows the entire communication cable to bend while preventing excessive stress on the signal line due to lateral bending, which is particularly important when the communication cable is used in applications requiring bending in confined spaces, such as inside a vehicle.

[0017] The bending-prevention element can comprise an element that exhibits flexibility in an axial direction of the at least one signal line and that is either arranged only laterally outside the at least one signal line, or that has both a laterally external section arranged laterally outside the at least one signal line and a vertically external section arranged vertically outside the at least one signal line, wherein the laterally external section has a greater thickness than the vertically external section. In this case, a thick element is arranged laterally outside the signal line, thus preventing the communication cable from bending laterally. However, no such element is arranged in the vertical direction, or if one is, its thickness is less.The cable's vertical bending is therefore hardly prevented. The flexible element is thus unevenly arranged around the signal line, effectively limiting its lateral bending.

[0018] In this case, it is preferred that the sheathing has a flat outer shape that is elongated in the lateral direction, and that the sheathing comprises a base material that serves as a restraint element, the laterally outer section of which is arranged outside the at least one signal line in the lateral direction, and the vertically outer section of which is arranged outside the at least one signal line in the vertical direction, wherein the laterally outer section has a greater thickness than the vertically outer section. Then, if the sheathing is formed, for example, by injection molding, it can be formed in a flat shape with different wall thicknesses in the vertical and lateral directions, thereby easily forming the bending restraint element that effectively restricts the bending of the signal line in the lateral direction.

[0019] Furthermore, it is preferred that the at least one signal line comprises several signal lines arranged side by side in the lateral direction, and that the sheathing encloses an arrangement of these multiple signal lines. Compared to the case where only the outer edge of one wire pair of a signal line is encased by the sheathing, the degree of flatness of the sheath's cross-sectional shape is then greater. The bending of the respective signal line in the lateral direction is thus restricted to a greater degree.

[0020] Furthermore, it is preferred that the base material of the sheathing is arranged continuously in an outer edge section located outside the arrangement of the multiple signal lines and in a middle section located between the multiple signal lines, and that the laterally outer section of the base material, when the thickness of the material in the outer edge section and the thickness of the material in the middle section are added, has a greater thickness than the vertically outer section. A large difference can then easily be generated between the thickness of the sheathing arranged laterally and the thickness arranged vertically outside the signal lines, with the thickness in the lateral direction being calculated as the sum of the thickness in the outer edge section and the thickness in the middle section.In addition to the effect of increasing the flatness of the cross-sectional shape of the communication cable, the bending of the signal lines in the lateral direction is thus restricted to a greater degree.

[0021] Alternatively, it is also preferred that the bending-limiting element comprises a high-tensile-strength fiber arranged laterally outside the at least one signal line and running along the axial direction of the at least one signal line. The presence of a high-tensile-strength fiber then prevents the communication cable from bending laterally. The bending of the signal line in the lateral direction is thus effectively limited by the high-tensile-strength fiber.

[0022] The bending restriction element can further comprise an element that is arranged outside the at least one signal line, has a larger dimension in the lateral direction than in the vertical direction, and exhibits greater stiffness than the sheathing. The bending restriction element can then be bent relatively easily in the vertical direction, but only with difficulty in the lateral direction. The bending of the signal line in the lateral direction is thus effectively restricted.

[0023] In this case, it is preferred that the bending restriction element is a plastic plate arranged vertically outside the at least one signal line, with one plane of the plate extending along an axial direction of the at least one signal line. It is then difficult to bend the plastic plate laterally, corresponding to folding in one plane of the plate, whereas it is comparatively easy to bend the plastic plate vertically, corresponding to deflection along the thickness of the plate. Bending of the signal line laterally is thus severely restricted, while easy bending in the vertical direction is effectively prevented.Furthermore, the bending restriction element is arranged with a larger dimension in the lateral direction outside the signal line in the vertical direction, which, compared to the case where the element is arranged in other positions, such as outside the signal line in the lateral direction, inhibits the increase in the diameter of the entire communication cable and achieves better signal symmetry in the signal line.

[0024] In all the cases described above, the insulating sheaths of the pair of insulated wires are preferably formed in one piece. A gap between the conductors forming the pair of insulated wires is then filled with the base material of the insulating sheaths as a continuous body, and this base material serves to restrict lateral bending of the signal line and also acts as a bending-limiting element. As a result, lateral bending of the signal line is supported. Details on example communication cables

[0025] Exemplary communication cables are now described in detail with reference to the attached drawings. Terms referring to the shape of elements / components, such as "approximately parallel" and "approximately circular," are not limited here to strictly geometric forms like exactly parallel and exactly circular shapes, but encompass deviations within a range permissible for communication cables. Overview of communication cable designs

[0026] Several embodiments of communication cables will be described later, but the common design of these embodiments will first be outlined below, wherein the communication cable 1 is designed according to the one in Fig. 1, Fig. 2A and Fig. Example 2B is used as an example.

[0027] The communication cable 1 (or one of 1A to 1D, referred to as the same in this section) has a signal line 10 with a pair of insulated wires 11, 11. The communication cable 1 also has a shielding body 20, 30 that surrounds the signal line 10, and a sheath 40 that surrounds the shielding body 20, 30.

[0028] Each of the insulated wires 11 forming the signal line has a conductor 12 and an insulating sheath 13 that surrounds the conductor 12. For flexibility, the conductor 12 is preferably a stranded wire. In the signal line 10, insulated wires 11, 11 are arranged side by side as a pair and are configured as parallel pairs of wires, which are in contact with each other approximately parallel in the axial direction. The signal line 10 can transmit differential signals.

[0029] The shielding body enclosing the signal line 10 comprises a foil shield 20 and / or a braided shield 30. The foil shield 20 is made of a foil-like material with a metal foil, which is a composite material such as a metal strip containing a combination of a metal foil and a substrate made of a material such as a polymer layer. Alternatively, the foil shield 20 can be formed using only a single metal foil. The braided shield 30 is formed by braiding thin metal wires into a hollow tube shape. Instead of the braided shield 30, a spiral-wound shield can be used. The spiral-wound shield is formed by spirally winding thin metal wires around the signal line 10.

[0030] The foil shield 20 and the braided shield 30 serve as shielding against noise penetrating the signal line 10 and noise emitted from the signal line 10 to the outside. Since the signal line 10 is designed as an untwisted parallel-pair cable, it is more susceptible to in-phase noise from the outside than a twisted signal line. The use of the shielding elements 20 and 30, however, serves to reduce the influence of external noise. The presence of the layered structure consisting of both the foil shield 20 and the braided shield 30 enables a particularly effective reduction of noise. In this case, the layer order of the foil shield 20 and the braided shield 30 is not restricted. However, if, as in Fig. 1, Fig. 2A and Fig. As illustrated in Figure 2B, if the foil shield 20 is arranged on the inside and the braided shield 30 on the outside, the foil shield 20 can achieve a greater improvement in transmission properties. Furthermore, the plastic forming the outer sheath 40 also adheres to the mesh of the braided shield 30, thus improving the adhesion between the shielding body 20, 30 and the outer sheath 40. If sufficient shielding is ensured by either the foil shield 20 or the braided shield 30 alone, then only the foil shield 20 or only the braided shield 30 can be used as the shielding.If only the foil-shaped shield 20 is used without the braided shield 30, it is preferred that a guide wire 25 is arranged within the area enclosed by the foil-shaped shield 20 for grounding purposes, and that current flow between the guide wire 25 and the foil-shaped shield 20 is ensured (see . Fig. 4A).

[0031] The sheath (the jacket) 40 is made of an insulating material such as plastic and encloses the shielding body 20, 30. The sheath 40 serves to physically protect the signal line 10 and the shielding body 20, 30 and is intended to help prevent the properties of the communication cable 1 from being impaired by contact with a substance such as water.

[0032] In addition to the components described above, the communication cable 1 has a bending restriction element. In this case, the signal line 10 has a lateral direction along which the pair of insulated wires 11, 11 are arranged side by side, defined as lateral direction a, and a direction that intersects the lateral direction a (i.e., is perpendicular to it) is defined as vertical direction b. The bending restriction element serves to limit the bending of the signal line 10 in the lateral direction a compared to the bending in the vertical direction b.Specifically, the bending restriction element inhibits the bending of the signal line 10 in the lateral direction a when a certain force is applied to the signal line 10 at a section central in the axial direction in order to bend the signal line 10 in the lateral direction a, compared to the case where the same force is applied to the signal line 10 in order to bend the signal line 10 in the vertical direction b.

[0033] As long as the bending restriction element serves the functions described above, its specific design is not limited, and communication cables according to the individual embodiments described below have bending restriction elements of different shapes. Representative shapes of each bending restriction element are illustrated below by way of example.

[0034] Type A: The bending restriction element exhibits flexibility in the axial direction of the signal line 10. The bending restriction element is either arranged only in the lateral direction a outside the signal line 10, or it has a laterally external section arranged in the lateral direction a outside the signal line 10 and a vertically external section arranged in the vertical direction b outside the signal line 10. The transverse section has a greater thickness than the vertical section.

[0035] Type B: The bending restriction element takes the form of an element that is arranged outside the signal line 10 in the vertical direction b. The element has a larger dimension in the lateral direction a than in the vertical direction b and has a greater stiffness than the sheathing 40.

[0036] In the type A described above, the bending restriction element exhibits flexibility in the axial direction of the signal line 10, and thus the material itself, forming the bending restriction element, allows bending in the vertical direction b as well as in the lateral direction a. However, due to its relative position to the signal line 10, the material achieves the function of restricting the bending direction of the signal line 10. Specifically, the base material of the bending restriction element has a greater thickness in the lateral direction a outside the signal line 10, so that the base material inhibits the bending of the signal line 10 in the lateral direction a compared to bending in the vertical direction b.In contrast, with type B, the bending of the signal line 10 is minimized in both the vertical direction b and the lateral direction a, since the bending-limiting element has a higher stiffness than the sheathing 40. Because the bending-limiting element has a shape with a small thickness in the vertical direction b, the degree of bending minimization is less when bending in the vertical direction b than when bending in the lateral direction a. Bending in the lateral direction a can therefore be prevented in comparison.

[0037] The communication cable 1 according to the embodiment of the present disclosure has the signal line 10 with parallel-pair wires and further comprises a shielding body 20, 30 around the signal line 10. The communication cable 1 can be suitable for transmitting differential signals in a high-frequency band such as 1 GHz or higher. If the signal line 10 is subjected to a load by bending, the bending may affect the transmission characteristics. Furthermore, the load caused by the bending may shorten the lifetime of the communication cable 1. The signal line 10 has the structure of a pair of side-by-side insulated wires 11, 11, and therefore the magnitude of the load exerted during bending exhibits anisotropy.Specifically, if the signal line 10 is bent at a section central in the axial direction, no large load is exerted on the signal line 10 when bending in the vertical direction b, whereas a large load is exerted on the signal line 10 when bending in the lateral direction a.

[0038] The communication cable 1 according to the embodiment of the present disclosure has, as described above, a bending-limiting element in which bending of the signal line 10 in the lateral direction a occurs less readily than in a conventional communication cable 9 without a bending-limiting element, as described in Fig. Figure 8 illustrates this. The load exerted on the signal line 10 by bending is therefore reduced. As a result, the influence of the load on the transmission characteristics due to bending is minimized, and the service life of the signal line 10 under bending is improved.

[0039] Examples of communication cables with different types of bending restraint elements are now described. Common reference symbols are used in the examples to indicate that the elements correspond to one another. The different types of bending restraint elements can be used as a combination of two or more types. First example: Cables with flat sheathing

[0040] Fig. 1, Fig. 2A and Fig. Figure 2B illustrates the design of the communication cable 1 according to an example. Fig. 3A and Fig. Figure 3B also illustrates the communication cable 1 when bent.

[0041] The communication cable 1 according to the example comprises: the signal conductor 10 with a pair of insulated wires 11, 11 arranged side by side; the shielding body formed by the foil shield 20 and the braided shield 30 enclosing the signal conductor 10; and the sheath 40 enclosing the shielding body 20, 30 as described above. Here, the sheath 40 has a flat shape, and because of this flat shape, the sheath 40 can itself act as a bending-limiting element of type A as described above.

[0042] Specifically, the casing 40 has a flat outer shape that is extended in the lateral direction a. That is, as in Fig. As illustrated in Figure 2A, the cross-section of the outer shape of the sheathing 40 has a maximum dimension in the lateral direction a that is larger than in the vertical direction b. In the illustrated form, the cross-section of the outer shape of the sheathing 40 is an ellipse. Furthermore, the base material of the sheathing 40 has a greater thickness in the section located outside the signal line 10 in the lateral direction a than in the section located outside in the vertical direction b. Specifically, the maximum value t1 of the wall thickness of the sheathing 40 in the lateral direction a is greater than the maximum value t2 of the wall thickness of the sheathing 40 in the vertical direction b (t1 > t2).

[0043] As in Fig. As illustrated in Figure 8, the outer shape of the sheath 94 of the conventional communication cable 9 is approximately circular in cross-section. The signal line 90, by accommodating a pair of insulated wires 91, 92 arranged side by side laterally, has an elongated shape in the lateral direction. Consequently, the outer shape of an arrangement comprising the signal line 90, the foil shield 92, and the braided shield 93 enclosing the signal line 90 also has a flat, elongated shape in the lateral direction. The sheath 94, with an approximately circular cross-section, is arranged over such a flat shape, with the wall thickness of the sheath 94 being smaller in the lateral direction a than in the vertical direction b. Thus, the sheath 94 has a smaller wall thickness in the lateral direction a outside the signal line 90.The sheathing 94 thus hardly prevents the signal line 90 from bending in the lateral direction a. As described above, if the signal line 90 is bent in the lateral direction a, a greater load is exerted on the signal line 90 than if it is bent in the vertical direction b.

[0044] In contrast to the conventional communication cable 9 described above, the sheath 40 in the communication cable 1 of the present example has a flat outer shape and a greater wall thickness in the lateral direction a than in the vertical direction b, which may restrict the bending of the signal line 10 in the lateral direction a compared to bending in the vertical direction b. The reason for this is as follows: To bend the entire communication cable 1 in the vertical direction b, it is only necessary to bend and deform the thin sheath material, and only a small degree of bending deformation is required for the sheath 40.However, in order to bend cable 1 in the lateral direction a, a bending deformation of the thick sheathing material is required; moreover, the extent of bending deformation is greater for compressing the sheathing material on the inside of the bend and for stretching the sheathing material on the outside.

[0045] Here, a situation is assumed in which the communication cable 1 with such a flat sheath 40 is bent at an axially central section towards the lateral direction a, as is the case in Fig. Figure 3A illustrates this. Such a bend is created, for example, along a cabling run when one end of the communication cable 1 is connected to a device that is arranged in the lateral direction a with respect to the axial direction. When the communication cable 1 is bent in the lateral direction a, a force is exerted on a rear section of the cable 1 in the lateral direction a (i.e., to the right in the figure) in a plane (i.e., the bend plane) in which the lateral direction a and the axial direction lie, while a front section of the cable is fixed. Here, the rear section on which the force is exerted is located behind the bend point in the figure, while the fixed front section is located in front of the point.

[0046] In this situation, as described above, the base material of the sheathing 40, which is flat and has a greater thickness in the lateral direction a than the bending-limiting element, serves as a base material, thus completely preventing the signal line 10 and the communication cable 1 from being bent directly in the lateral direction a in the bending plane. In other words, the communication cable 1 cannot be bent simultaneously in the lateral direction a and maintain the orientation of the side-by-side arrangement of the pair of insulated wires 11, 11 in the bending plane. As shown in the perspective view in Fig. 3B and the cross-sectional view along AA in Fig. As illustrated in Figure 2B, the communication cable 1 is then rotated (according to a rotation r) and twisted about the axial direction. As shown by imaginary guide lines G in Fig. 3A and Fig. As shown in Figure 3B, this twist causes the axial direction of the communication cable 1 to bend out of the plane. Between regions A1 and A2 before and after the bending point, respectively, a cross-section of the communication cable 1 is then rotated by approximately 90 degrees. Specifically, in region A1 on the front side, the pair of insulated wires 11, 11 remain arranged side by side in the lateral direction a, while in region A2 on the rear side, the pair of insulated wires 11, 11 are now arranged side by side in the vertical direction b.

[0047] In this way, the twisting of the entire communication cable 1 absorbs the force exerted on the entire communication cable 1 in the lateral direction a in the bending plane. As a result, this leads to a reduction in the force on the signal line 10 located within the area enclosed by the sheath 40, thus preventing the signal line 10 from bending in the lateral direction a in the bending plane. The signal line 10 follows the bend of the entire communication cable 1 primarily by a twist that is associated with the bending in the vertical direction b and not with the bending in the lateral direction a.Limiting the bending of the signal line 10 in the lateral direction a prevents the signal line 10 from being subjected to a large load by bending, thereby minimizing the effects on the transmission characteristics caused by the load due to such bending and counteracting a reduction in service life.

[0048] The base material of the sheathing 40 is not specifically limited; however, materials with comparatively low flexibility provide the advantageous effect of preventing the signal line 10 from bending in the lateral direction a. For example, the wall thickness t1 in the lateral direction a is preferably greater than the wall thickness of the insulating sheath 13.

[0049] The sheath 40, which is conventionally included in a communication cable to protect the shielding body 20, 30 and the signal line 10, also serves as the bending-limiting element in the present example. The integration of the bending-limiting element into the communication cable 1 is thus achieved with a simple design. Furthermore, when the sheath 40 is formed by injection molding a plastic composition, the bending-limiting element can be easily created by selecting different wall thicknesses t1, t2 of the sheath 40 in the lateral and vertical directions.

[0050] Modified examples can be found, as in Fig. As illustrated in Figure 4A, a communication cable 1A comprises several signal lines 10, which are jointly enclosed by a flat sheath 40. Here, two groups, each comprising a signal line 10 and a guide wire 25, as well as the foil-shaped shield 20 that encloses them, are arranged side by side in the lateral direction a. The outer edges of an arrangement with the two groups are jointly enclosed by a continuous sheath 40. The sheath 40 has a flat outer shape that is longer in the lateral direction a. The sheath 40 is arranged in outer edge sections 41, 42, which correspond to the outer edge of the arrangement with the two pairs of signal lines 10, and in a central section 42, which corresponds to a position between the two wire pairs of the two signal lines 10.The base material of the sheathing 40, arranged in the outer edge sections 41, 41 and the middle section 42, is completely continuous. If the thicknesses of the base material of the sheathing 40 in the outer edge sections 41, 41 and in the middle section 42 are added, the thickness (t3 + t3 + t4) of the material arranged in the lateral direction a outside the signal line 10 is greater than the thickness (t5 + t5) of the material in the vertical direction b.

[0051] In this way, by encasing several signal lines 10 with a flat sheath 40, the degree of flatness of the sheath 40 is greater and the sheath 40 is longer in the lateral direction than in the case where the sheath 40 is, as in Fig. As illustrated in Figures 1 to 3B, only a single pair of signal lines 10 is encased. As a result, the flatter shape of the sheathing 40 further enhances the effect of restricting the bending of the signal lines 10 in the lateral direction a. The restriction of the individual signal lines 10's bending in the lateral direction a is provided not only by the sheathing material located in the outer edge sections 41, 41, but also by the sheathing material located in the central section 42. Accordingly, the wall thickness of the sheathing 40, which is located in the lateral direction a of the signal lines 10 and has the effect of preventing the signal lines 10 from bending in the lateral direction, is defined by the sum of the thicknesses in the outer edge sections 41, 41, and in the central section 42.The wall thickness in the lateral direction a, as a ratio to the wall thickness in the vertical direction b, is then greater than in the case where the sheathing 40 only encloses a single pair of signal lines 10. This provides a stronger effect on restricting the bending of the signal lines 10 in the lateral direction a. If a wall thickness (t3) in the outer edge sections 41, 41 alone is greater than the wall thickness (t5) in the vertical direction b, the bending of the signal line 10 in the lateral direction a is more strongly restricted.

[0052] In communication cable 1A in Fig. 4A only the foil-shaped shields 20, which individually enclose the signal lines 10, are arranged as shielding bodies. Alternatively, the braided shield 30 can also be used as in a Fig. The communication cable 1A' illustrated in Figure 4B is arranged as follows: In this case, the two groups, each comprising the foil-shaped shield 20 that encloses the respective signal line 10, are arranged side by side in the lateral direction a, and the braided shield 30 encloses the arrangement comprising the outer edges of both sets jointly. Furthermore, the sheath 40 encloses the arrangement over the braided shield 30 jointly. There is no need to include a guide wire 25.

[0053] In this case, the thickness (t3') of the base material of the sheathing 40, arranged in the lateral direction a outside the signal line 10 (in the outer edge sections 41, 41), is greater than the thickness (t5') in the vertical direction b. As with the communication cable 1A in Fig. 4A In this form, the communication cable 1A' also exhibits an increased effect of limiting the bending of the signal line 10 in the lateral direction a due to the flat shape of the sheathing 40. Unlike the communication cable 1A in Fig. 4A has no sheathing material at a position corresponding to the middle section 42. Therefore, although no bending restriction effect in the lateral direction a is achieved by the sheathing material in the middle section 42, the communication cable 1A' has a simpler design due to the absence of the guide wire 25.

[0054] A further modified example may include a communication cable 1B in which a pair of insulated wires has a one-piece molded insulating sheath 13'. Specifically, two conductors 12, 12 are enclosed by a one-piece continuous insulating sheath 13', without, as in Fig. Figures 1 to 3B illustrate that each conductor is individually encased by its independent insulating sheath 13. In this way, by forming the insulating sheath 13' in one piece, the entire area between the pair of conductors 12, 12 arranged side by side in the lateral direction is covered by the base material of the insulating sheath 13'.

[0055] In such a shape, the insulating sheath material 13', which continuously covers the area between the two conductors 12, 12 in the lateral direction a, also has the effect of making the signal line 10 less flexible in the lateral direction a. That is, the insulating sheath material 13' supports the function of the flat sheath 40 as a bending-limiting element. In combination with bending-limiting elements of different shapes, including those according to the present embodiment, the effect of limiting the bending of the signal line 10 in the lateral direction a can therefore be enhanced throughout the entire communication cable. Second embodiment: Cable with high tensile strength fiber

[0056] Fig. Figure 6 illustrates a communication cable 1C according to a second embodiment of the present disclosure.

[0057] In the communication cable 1C according to the second embodiment, an intermediate cord 50 made of high-tensile fiber is arranged in the lateral direction a outside an assembly that comprises the signal line 10 and the braided shield 30, which encloses the signal line 10. The intermediate cord 50 lies directly adjacent to the assembly and extends in the axial direction of the signal line 10. In other words, the intermediate cords 50 and 50 are arranged along the braided shield 30 on both sides of the signal line 10 that are outer in the lateral direction a. The intermediate cord 50 serves as a bending-limiting element according to the type A described above. The intermediate cord 50 is an elongated, flexible element made of a high-tensile fiber, such as an aramid-based material.An intermediate cord can be used that is similar to the one arranged inside a sheath in various known cables.

[0058] In communication cable 1C, the sheath 40 further encloses an arrangement comprising the signal line 10, the braided sheath 30, and the intermediate cords 50, 50 on both sides. The sheath 40 has an outer shape with an approximately circular cross-section.

[0059] Since the intermediate cord 50 is located outside the signal line 10 in the lateral direction a, bending the communication cable 1C in the lateral direction a requires bending not only the signal line 10 but also the intermediate cord 50 in the lateral direction a at an axially central section. Therefore, compared to the case where the same force is applied to a cable without an intermediate cord 50 in the plane of the bend, bending the communication cable 1C in the lateral direction a is more difficult. Furthermore, bending the communication cable 1C in the lateral direction a exerts a particularly large tensile force on the intermediate cord 50, which is located on the outside of the bend. Unlike the sheath 40, the intermediate cord 50 does not expand when a tensile force is applied. The tensile force exerted on the intermediate cord 50 thus counteracts the bending of the communication cable 1C in the lateral direction a.

[0060] In this way, the presence of the intermediate cord 50 prevents the entire communication cable 1C and the signal line 10 from being bent in the lateral direction a, while it has no significant effect on the bending of the entire communication cable 1C and the signal line 10 in the vertical direction b. Accordingly, the intermediate cord 50, located outside the signal line 10 in the lateral direction a, acts as a bending-limiting element, restricting bending in the lateral direction a compared to bending in the vertical direction b. If the intention is to bend the communication cable 1C, the intermediate cord 50, as a bending-limiting element, prevents bending in the lateral direction a and thereby causes the signal line 10 to be bent in the vertical direction b instead of in the lateral direction a, thus guiding the direction of bending.

[0061] Even if the intermediate cord 50 is arranged on only one side of the signal line 10 in the lateral direction a, it still exerts a certain degree of effect as a bending-limiting element. However, to effectively prevent the signal line 10 from bending in both directions of the lateral direction a, the intermediate cords 50 and 50 are preferably arranged on both sides of the signal line 10 in the lateral direction a, as shown in Fig. Figure 6 illustrates this. Although an intermediate cord (or several intermediate cords) 50 can also be arranged outside the signal line 10 in the vertical direction b, in this case it is necessary that the thickness of the area occupied by the intermediate cords 50 in the lateral direction a of the signal line 10 is greater than in the vertical direction b.

[0062] At the in Fig. In the illustrated form 6, the intermediate cord 50 is arranged outside the area enclosed by the braided shield 30. In another possible form, the intermediate cord 50 can be arranged inside the shield body. However, the intermediate cord 50 can achieve a greater effect in preventing the signal line 10 from bending laterally in the direction a if it is arranged as in Fig. As illustrated in Figure 6, the intermediate conductor 50 is located outside the area enclosed by the braided shield 30 because the distance to the signal line 10 is greater. Furthermore, good signal symmetry can be maintained more effectively in the signal line 10. If, on the other hand, the intermediate conductor 50 is located within the area enclosed by the shielding body, the electromagnetic coupling between the insulated wires 11 that form the signal line 10 is greater, thus enhancing the effects of reduced propagation delay and improved noise resistance. In addition, the intermediate conductor can be more easily incorporated during the manufacture of the communication cable 1C. Third embodiment: Cable with plastic plate

[0063] Fig. Figure 7 illustrates the design of a communication cable 1D according to a third embodiment of the present disclosure.

[0064] In the communication cable 1D according to the third embodiment, a plastic plate 60 is arranged outside the signal line 10 in the vertical direction b, with the plane of the plate running along the axial direction of the signal line 10. The plastic plate 60 has a higher stiffness than the base material of the sheathing 40, so that the plastic plate 60 is more resistant to bending deformation in all directions than the sheathing 40. The plastic plate 60 serves as a bending-limiting element according to the type B described above.

[0065] In communication cable 1D, the signal conductor 10 is encased by the braided shield 30. Furthermore, the plastic plates 60 are arranged at positions in the vertical direction b outside the braided shield 30 on both sides of the signal conductor 10. In other words, an assembly comprising the signal conductor 10 and the braided shield 30, which encases the signal conductor 10, is enclosed between the two plastic plates 60, 60. The assembly comprising the signal conductor 10, the braided shield 30, and the plastic plates 60, 60 is enclosed by the sheath 40. In this case, the sheath 40 has an outer shape with an approximately circular cross-section.

[0066] The plastic sheet 60 can be bent relatively easily in its thickness direction, but it cannot be easily bent in any direction within the plane that intersects the thickness direction. That is, if, as in Fig. As illustrated in Figure 7, the plastic plate 60 is arranged such that the plane of the plate runs in the axial direction of the signal line 10 and the thickness direction is directed in the vertical direction b, the plastic plate 60 can be bent relatively easily in the vertical direction b, but not easily in the lateral direction a.

[0067] The communication cable 1D is provided with the plastic plate 60, which has a higher stiffness than the sheathing 40. This prevents bending in both the lateral direction a and the vertical direction b compared to a cable without the plastic plate 60. Due to the anisotropy of the ease of bending of the plastic plate 60, as described above, the degree of bending prevention is greater for bending in the lateral direction a than for bending in the vertical direction b. Therefore, the bending of the communication cable 1D and the signal line 10 in the lateral direction a is restricted compared to bending in the vertical direction b, and the plastic plate 60 thus serves as a bending-limiting element.If the intention is to bend the communication cable 1D, the plastic plate 60, as a bending restriction element, prevents bending in the lateral direction a more strongly than bending in the vertical direction, thereby causing the signal line 10 to be bent in the vertical direction b instead of in the lateral direction a, and guides the bending direction.

[0068] An element other than the plastic plate 60 can be used as a bending restraint element of type B, provided that the element is made of a material that has a higher stiffness than the base material of the sheath 40 and is plate-shaped with a larger dimension (width) in the lateral direction a than its dimension (thickness) in the vertical direction b. However, a material that completely inhibits any bending in the vertical direction b would make it impossible to bend the communication cable 1D in any direction. Therefore, a material that exhibits some degree of flexibility is preferred. In view of this, the use of a plastic plate 60 made of a material such as polyolefins and polyvinyl chloride is preferred.

[0069] The position at which such a plate-shaped bending-limiting element is arranged is not limited to the position in the vertical direction b outside the signal line 10; it can be arranged at any position outside the signal line 10. However, with regard to preventing excessive increase in the diameter of the signal line 10 and with regard to improved signal symmetry of the signal line 10, the bending-limiting element is preferably arranged in the vertical direction b outside the signal line 10, as in the form described above. Furthermore, by arranging the plate-shaped element 50 in the vertical direction b outside the signal line 10, a plate-shaped element 50 with a greater width can be used. If the plate-shaped element 50 has a greater width, the bending-limiting effect of the signal line 10 in the lateral direction a is more favorable.The plate-shaped element preferably has a width that is greater than or equal to a dimension of the signal line 10 in the lateral direction a. Furthermore, the plate-shaped element can be arranged on only one side or on both sides of the signal line 10 in the vertical direction; however, if it is arranged on both sides, the effect of limiting the bending in the lateral direction a is increased. REFERENCE MARK LIST 1, 1A to 1D, 1A' Communication cable 10 Signal line 11 insulated wire 12 ladders 13, 13' Insulating cover 20 foil-shaped shields 25 guide wire 30 braided shields 40 sheathing 41 Outer edge section 42 middle section 50 Intermediate cord (high-tensile fiber) 60 plastic sheets 9 conventional communication cables 90 Signal line 91 insulated wire 92 foil-shaped shielding 93 braided shielding 94 Sheathing a lateral direction b vertical direction r rotational movement t1 Maximum value of the casing wall thickness in the lateral direction t2 Maximum value of the casing wall thickness in the vertical direction t3, t3' Sheathing wall thickness in the lateral direction in the outer edge section of the signal line t4 Wall thickness of the base material of the sheathing between two signal wire pairs t5, t5' Sheathing wall thickness in the vertical direction A1 area on the front A2 area on the back G Guideline

Claims

[1] Communication cable (1C), comprising: at least one signal line (10) comprising a pair of side-by-side insulated wires (11), each insulated wire (11) comprising a conductor (12) and an insulating sheath (13) enclosing the conductor (12); a shielding body (30) that encloses the at least one signal line (10); a casing (40) that encloses the shielding body (30) and has an outer shape with an approximately circular cross-section; and a high tensile strength fiber (50), where, if a direction along which the pair of insulated wires (11) is arranged side by side is defined as the lateral direction (a) and a direction which intersects the lateral direction is defined as the vertical direction (b), the high-tensile fiber (50) is arranged in the lateral direction (a) outside the at least one signal line (10) and runs along an axial direction of the at least one signal line (10), and the high tensile strength fiber (50) acts as a bending restriction element which restricts bending of the at least one signal line (10) in the lateral direction (a) compared to bending of the at least one signal line (10) in the vertical direction (b). [2] Communication cable according to claim 1, wherein the high tensile strength fiber (50) comprises an aramid-based material. [3] Communication cable according to claim 1 or 2, wherein the high tensile strength fiber (50) is arranged outside an area enclosed by the shielding body (30). [4] Communication cable according to one of claims 1 to 3, wherein the high tensile strength fiber (50) is arranged in the lateral direction (a) on both sides of the at least one signal line (10). [5] Communication cable (1D), comprising: at least one signal line (10) comprising a pair of side-by-side insulated wires (11), each insulated wire (11) comprising a conductor (12) and an insulating sheath (13) enclosing the conductor (12); a shielding body (30) that encloses the at least one signal line (10); a casing (40) that encloses the shielding body (30) and has an outer shape with an approximately circular cross-section; and a plastic sheet (60), where, if a direction along which the pair of insulated wires (11) is arranged side by side is defined as the lateral direction (a) and a direction which intersects the lateral direction is defined as the vertical (b) direction, the plastic plate (60) is arranged in the vertical direction outside the at least one signal line (10), wherein a plane of the plate (60) extends along an axial direction of the at least one signal line (10), and the plastic plate (60) acts as a bending restriction element, which restricts bending of the at least one signal line (10) in the lateral direction (a) compared to bending of the at least one signal line (10) in the vertical direction (b). [6] Communication cable according to claim 5, wherein the plastic plate (60) comprises polyolefin or polyvinyl chloride. [7] Communication cable according to claim 5 or 6, wherein the plastic plate (60) has a width that is greater than or equal to a dimension of the at least one signal line (10) in the lateral direction (a). [8] Communication cable according to any one of claims 1 to 7, wherein the insulating sheaths (13) of the pair of insulated wires (11) are formed in one piece.

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