Composite cable

Abstract

The present invention provides a composite cable that improves high-frequency characteristics. The composite cable (1) has a signal transmission cable (2), a pair of power lines (3), an integral braided shielding layer (5), and a sheath (6); the signal transmission cable (2) has a pair of signal lines (21) arranged parallel to each other in the cable length direction and arranged to contact each other, and a shielding layer (22) integrally covering the pair of signal lines (21); the pair of power lines (3) are arranged to contact each other and to contact the shielding layer (22); the integral braided shielding layer (5) integrally covers the periphery of the cable core (4) formed by the signal transmission cable (2) and the pair of power lines (3); the sheath (6) covers the periphery of the integral braided shielding layer (5); wherein the integral braided shielding layer (5) is arranged along the outline of the shielding layer (22) and is tightly connected to the shielding layer (22).

Description

Technical Field

[0001] This invention relates to composite cables. Background Technology

[0002] As an existing type of cable, composite cables, which combine power lines and signal lines, are widely used (for example, see Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2011-90866 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In recent years, the development of autonomous driving technology has progressed in automobiles and other fields. The image quality of cameras used in autonomous driving has improved significantly, requiring composite cables capable of transmitting large volumes of image information and achieving very high signal transmission speeds. Furthermore, composite cables used in automotive cameras, including those with cabling lengths of several meters, require excellent high-frequency characteristics for high-speed signal transmission over long distances. From the perspective of ensuring the safety of autonomous driving, composite cables capable of stable high-speed transmission are needed.

[0008] However, existing composite cables are prone to high-frequency characteristic degradation, especially when they are bent, and there is a desire to further improve their high-frequency characteristics.

[0009] Therefore, the purpose of this invention is to provide a composite cable that can improve high-frequency characteristics.

[0010] Methods for solving problems

[0011] To address the aforementioned issues, this invention provides a composite cable comprising a signal transmission cable, a pair of power lines, an integral braided shielding layer, and a sheath. The signal transmission cable has a pair of signal lines configured to be parallel to each other and in contact with each other along the cable's length, and a shielding layer integrally covering the pair of signal lines. The pair of power lines are configured to be in contact with each other and to contact the shielding layer. The integral braided shielding layer integrally covers the periphery of the cable core formed by the signal transmission cable and the pair of power lines. The sheath covers the periphery of the integral braided shielding layer. The integral braided shielding layer is configured to follow the outline of the shielding layer and be tightly connected to it.

[0012] Invention Effects

[0013] According to the present invention, a composite cable capable of improving high-frequency characteristics is provided. Attached Figure Description

[0014] Figure 1 This is a cross-sectional view of a composite cable according to an embodiment of the present invention, perpendicular to its length direction.

[0015] Figure 2 For illustrative purposes Figure 1 A three-dimensional view of the end treatment of the composite cable shown.

[0016] Figure 3 This is a cross-sectional view of the metal strip used for the shielding layer.

[0017] Explanation of reference numerals in the attached figures

[0018] 1…Composite cable, 2…Signal transmission cable, 21…Signal line, 211…Signal conductor, 212…Insulator, 212a…Inner insulator, 212b…Outer insulator, 22…Shielding layer, 22a…Flat portion, 22b…Bend portion, 221…Resin layer, 222…Metal layer, 223…Adhesive layer, 23…Resin tape, 3…Power cord, 31…Conductor, 32…Insulator, 4…Cable core, 5…Integral braided shielding layer, 6…Sheath, V…Virtual line. Detailed Implementation

[0019] The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0020] Figure 1 This is a cross-sectional view showing the cross-section of the composite cable according to this embodiment, perpendicular to its length. Figure 1 The composite cable 1 shown is, for example, a cable used for wiring of a camera mounted on a vehicle (e.g., a camera used for autonomous driving).

[0021] like Figure 1 As shown, the composite cable 1 has a signal transmission cable 2, a pair of power lines 3, an integrally braided shielding layer 5 that is integrally wrapped around a cable core 4 obtained by twisting the signal transmission cable 2 and the pair of power lines 3, and a sheath 6 that is wrapped around the integrally braided shielding layer 5. The transmission cable 2 has a pair of signal lines 21 and a shielding layer 22 that integrally wraps around the pair of signal lines 21.

[0022] (Power cord 3)

[0023] A pair of power cords 3 are used to provide power to a camera or similar device. Each pair of power cords 3 has a conductor 31 and an insulator 32 surrounding the conductor 31. The conductor 31 is formed by stranding multiple bare metal wires together. The bare metal wires used as conductors 31 can be soft copper wire, copper alloy wire, or a plated material. In this embodiment, the conductor 31 is formed by concentrically stranding seven bare metal wires of tin-plated soft copper wire with an outer diameter of 0.16 mm. The insulator 32 can be, for example, a material formed from a polyvinyl chloride resin composition. The outer diameter of the conductor 31 is, for example, 0.40 mm or more and 0.50 mm or less. The two power cords 3 can be configured to be parallel to each other along the length of the cable.

[0024] (Signal transmission cable 2)

[0025] The signal transmission cable 2 is used to transmit image signals from a camera, etc. The signal transmission cable 2 has a pair of signal lines 21 configured to be parallel to each other and in contact with each other along the length of the cable, and a shielding layer 22 that integrally covers the pair of signal lines 21.

[0026] Each pair of signal lines 21 has a signal conductor 211 and an insulator 212 surrounding the signal conductor 211. The signal conductor 211 is composed of a stranded conductor formed by twisting together multiple bare metal wires. The bare metal wires used as the signal conductor 211 can be soft copper wire, copper alloy wire, or materials that have been tin-plated or silver-plated. In this embodiment, the signal line 21 is constructed using bare metal wires made of soft copper wire with high conductivity silver plating. Alternatively, the signal conductor 211 can be a compressed stranded conductor that has been lightly compressed to form a circular cross-section. By constructing the signal conductor 211 with a compressed stranded conductor, the gap between the bare metal wires can be reduced, thereby significantly reducing the conductor resistance of the signal conductor 211, and enabling the signal conductor 211 to achieve excellent bending resistance. The conductor cross-sectional area of ​​the signal conductor 211 can be the same as or larger than the conductor cross-sectional area of ​​the conductor 31 of the power line 3. This facilitates high-speed transmission of signals such as image signals from a camera. It should be noted that the conductor cross-sectional area of ​​the conductor 31 is, for example, 0.12 mm². 2 Above 0.20mm 2 the following.

[0027] To maintain good high-frequency characteristics, it is desirable to use a material with a low dielectric constant as much as possible for the insulator 212. Furthermore, the thickness of the insulator 212 can be adjusted to achieve the desired characteristic impedance of the signal line 21. In this embodiment, the thickness of the insulator 212 is adjusted to set the characteristic impedance of the signal line 21 to 50Ω (the overall characteristic impedance of the signal transmission cable 2 is 100Ω). It should be noted that the characteristic impedance of the signal transmission cable 2 can be 100±5Ω. The characteristic impedance can be measured, for example, using the TDR (Time Domain Reflectometry) method. Here, when the thickness of the insulator 212 is adjusted to make the characteristic impedance of the signal line 21 50Ω, the insulator 212 becomes thicker, thus increasing the outer diameter of the signal line 21, which poses a risk of difficulty in connecting with existing connectors. Therefore, in this embodiment, the insulator 212 is composed of an inner layer insulator 212a surrounding the signal conductor 211 and an outer layer insulator 212b surrounding the inner layer insulator 212a.

[0028] Therefore, as Figure 2 As shown, during end processing, the outer insulator 212b is peeled off from the inner insulator 212a. This reduces the outer diameter of the signal line 21 at the cable end, allowing the exposed portion of the inner insulator 212a to be connected to the connector. Therefore, it is easy to connect to existing, highly versatile connectors. In other words, it achieves two goals: increasing the thickness of the insulator 212 of the signal line 21 (increasing the outer diameter of the signal line 21) to improve characteristic impedance for high-speed signal transmission from the camera, and connecting the cable end to the connector without altering the connector structure (e.g., not changing the position of the connector pins used to connect the signal conductor 211 to accommodate the increased diameter of the signal line 21). The outer diameter of the inner insulator 212a can, for example, be greater than or equal to the outer diameter of the power line 3. For example, the outer diameter of the inner insulator 212a can be more than 1.5 times the outer diameter of the power line 3.

[0029] The inner insulator 212a can be formed by full extrusion (full extrusion) or tubular extrusion. In particular, when the inner insulator 212a is formed by tubular extrusion, it is easier to peel the inner insulator 212a from the signal conductor 211, and the operability of end processing for connection to connectors, etc. at the cable end is improved. In addition, when the inner insulator 212a is formed by tubular extrusion, the signal conductor 211 can easily move inside the inner insulator 212a when the composite cable 1 is bent or twisted, which improves the resistance to bending or twisting.

[0030] The outer insulator 212b can be formed by tube extrusion. As a result, the inner surface of the outer insulator 212b is difficult to bond with the outer surface of the inner insulator 212a. Therefore, when performing end treatment at the end of the cable for connecting connectors, etc., it is easy to peel the outer insulator 212b from the outer surface of the inner insulator 212a, thus improving the operability of the end treatment.

[0031] During the formation of the outer insulator 212b (during extrusion molding), to prevent the outer insulator 212b from fusing to the inner insulator 212a, a resin with a lower melting point than that used for the inner insulator 212a can be used as the resin for the outer insulator 212b. The melting point of the resin used for the inner insulator 212a is, for example, 250°C or higher and 330°C or lower. The melting point of the resin used for the outer insulator 212b is, for example, 90°C or higher and 170°C or lower. Furthermore, to maintain high-frequency characteristics, the inner insulator 212a, which is closer to the signal conductor 211, can have a lower dielectric constant than the outer insulator 212b. The dielectric constant of the inner insulator 212a can, for example, be 2.0 or higher and 2.8 or lower (more preferably 2.1 or higher and 2.6 or lower). Furthermore, to maintain high-frequency characteristics, the thickness of the inner insulator 212a can be greater than the thickness of the outer insulator 212b. The thickness of the inner insulator 212a is, for example, 1.5 to 2.0 times (more preferably 1.6 to 1.7 times) the thickness of the outer insulator 212b. In this embodiment, fluoropolymers such as FEP (tetrafluoroethylene-hexafluoropropylene copolymer) and PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), which have low dielectric constants, are used as the inner insulator 212a. Furthermore, resins such as PE (polyethylene) and PP (polypropylene), which have low dielectric constants and are difficult to weld to the inner insulator 212a formed from fluoropolymers, are used as the outer insulator 212b.

[0032] Furthermore, the inner insulator 212a and the outer insulator 212b can be stretched by more than 150%. Therefore, by arranging the two signal lines 21 parallel to each other and in contact with each other along the cable length, it is difficult for the two signal lines 21 to move even when bent, and it is unlikely that the inner insulator 212a or the outer insulator 212b will break due to bending or twisting. Thus, the signal transmission cable 2 can stably transmit signals even when routed with bending or other bending.

[0033] As described above, in this embodiment, in order to set the characteristic impedance of signal line 21 to a desired value, the outer diameter of signal line 21 becomes relatively large. Therefore, the outer diameter of power line 3 is smaller than that of signal line 21. More specifically, the outer diameter of power line 3 is 0.5 times or more but less than 1 times the outer diameter of signal line 21. In this embodiment, the outer diameter of signal line 21 is 1.50 mm or more but less than 1.80 mm, and the outer diameter of power line 3 is 1.00 mm or more but less than 1.50 mm.

[0034] A pair of signal lines 21 are configured to be parallel to each other and in contact with each other. That is, the signal transmission cable 2 is a two-core parallel cable. Furthermore, a resin tape made of PET (polyethylene terephthalate) or the like is spirally wound around the pair of signal lines 21. A metal tape is spirally wound around the resin tape 23 to form a shielding layer 22.

[0035] like Figure 3 As shown, the metal strip constituting the shielding layer 22 has a metal layer 222 formed on one side of the resin layer 221, and an adhesive layer 223 formed on the other side of the resin layer. In this embodiment, a metal strip formed of Al / PET is used, that is, a metal layer 222 formed of Al (aluminum) is formed on one side of the resin layer 221 made of PET (polyethylene terephthalate), and an adhesive layer 223 formed of thermosetting resin is formed on the other side of the resin layer 221. However, it is not limited to this, and a metal strip with a copper metal layer 222 can also be used. In addition, a metal strip with the resin layer 221 made of polyester resin other than PET can also be used.

[0036] The shielding layer 22 is configured such that a metal strip is spirally wound around the resin strip 23, with the adhesive layer 223 located on the resin strip 23 side (the metal layer 222 located on the integrally braided shielding layer 5 side). After the metal strip is wound around the resin strip 23, heating is used to bond the metal strips together and between the metal strips and the resin strip 23 using the thermosetting resin constituting the adhesive layer 223. This structure allows for a more secure hold of the pair of signal lines 21. Furthermore, it suppresses the peeling of the shielding layer 22 from the signal lines 21, inhibits positional shifts in the signal lines 21 due to peeling, and suppresses changes in the distance between the signal lines 21 and the shielding layer 22 during bending, thus suppressing degradation of high-frequency characteristics. Additionally, since the shielding layer 22 is not directly bonded to the signal lines 21, it can be easily removed from the signal lines 21 during end-processing, improving operability during end-processing.

[0037] The winding direction of the metal strip constituting the shielding layer 22 is preferably different from the winding direction of the resin strip 23 that forms its base. This allows the metal strip and resin strip 23 constituting the shielding layer 22 to be firmly bonded, and the positions of the two parallel signal lines 21 are less likely to change due to bending or twisting. Furthermore, since the signal lines 21 are less likely to twist, the distance between them can remain constant, ensuring stable characteristic impedance along the cable length. It should be noted that the winding direction of the metal strip and resin strip 23 refers to the direction of rotation of the metal strip and resin strip 23 from one end to the other when viewed from one end of the signal transmission cable 2.

[0038] The shielding layer 22 is formed in a generally elliptical shape (a rectangle with rounded corners) in a cross-sectional view perpendicular to the length of the cable, and integrally formed with a pair of flat portions 22a extending in a straight line along the arrangement direction of a pair of signal lines 21 and a pair of curved portions 22b connecting the ends of the pair of flat portions 22a.

[0039] (Cable core 4)

[0040] The cable core 4 is constructed by twisting (rigidly twisting) the signal transmission cable 2 together with a pair of power lines 3. That is, the signal transmission cable 2 and the power lines 3 are twisted at the same spacing. The twisting direction of the cable core 4 can be the same as the winding direction of the metal strip constituting the shielding layer 22. This suppresses the opening (loosening) of the metal strip constituting the shielding layer 22 due to the twisting of the cable core 4, resulting in stable high-frequency characteristics. It should be noted that the twisting direction of the cable core 4 refers to the rotation direction of the transmission cable 2 and power lines 3 from one end of the cable core 4 towards the other end.

[0041] A pair of power lines 3 are configured to be parallel to each other and in contact with each other, and are respectively configured to contact the outer surface of the shielding layer 22 of the signal transmission cable 2. That is, in the circumferential direction of the cable, one power line 3, another power line 3, and the signal transmission cable 2 are arranged sequentially, with the two power lines 3 in contact with the signal transmission cable 2. Each of the pair of power lines 3 is configured to contact one side flat portion 22a of the shielding layer 22. It should be noted that the two power lines 3 can be twisted together, but from the viewpoint of minimizing the diameter of the composite cable 1 and fixing the position of the signal transmission cable 2 within the cable core 4 (making it difficult to move), the two power lines 3 can also be configured to be parallel to each other in the cable length direction. In addition, the two power lines 3 are configured such that the insulator 32 is in contact with the integral braided shielding layer 5.

[0042] Furthermore, the arrangement of the pair of power lines 3 is almost identical to that of the pair of signal lines 21. The middle positions of the pair of power lines 3 (the contact points between the power lines 3) and the middle positions of the pair of signal lines 21 (the contact points between the signal lines 21) are parallel to each other in a direction perpendicular to the arrangement of the power lines 3 and the signal lines 21. Thus, in a cross-sectional view perpendicular to the cable length direction, the cable core 4 is configured such that the virtual line V formed by connecting the centers of the pair of signal lines 21 and the pair of power lines 3 is trapezoidal.

[0043] (Integrated braided shielding layer 5)

[0044] The integrated braided shielding layer 5 is configured to integrally cover the periphery of the cable core 4. The integrated braided shielding layer 5 is constructed by braiding bare metal wires. The bare metal wires used for the integrated braided shielding layer 5 can be soft copper wire, copper alloy wire, aluminum wire, aluminum alloy wire, etc. Alternatively, copper foil wires obtained by spirally winding copper foil around a filament can also be used as the bare metal wires for the integrated braided shielding layer 5.

[0045] In the composite cable 1 according to this embodiment, the integral braided shielding layer 5 follows the outline of the shielding layer 22 of the signal transmission cable 2 and is tightly connected to the shielding layer 22. More specifically, the integral braided shielding layer 5 is configured such that its inner surface is tightly connected without gap to the outer surface (surface of metal layer 222) of the entire flat portion 22a on the side of the shielding layer 22 that is not in contact with the pair of power lines 3, and to a portion of the outer surface (surface of metal layer 222) of the pair of curved portions 22b on both sides of the flat portion 22a. The integral braided shielding layer 5 only needs to be tightly connected to at least half of the outer surface of the curved portion 22b. It should be noted that the term "tightly connected" here includes not only the state of contact without gap, but also the situation where there is a small gap within the range of satisfying the effect of the present invention, as described later. That is, a small gap that does not hinder the effect of the present invention is allowed between the shielding layer 22 and the integral braided shielding layer 5.

[0046] Furthermore, in composite cable 1, no drain wire is provided between the shielding layer 22 and the integrated braided shielding layer 5. This is because if a drain wire were provided between the shielding layer 22 and the integrated braided shielding layer 5, a gap would appear between them, creating a potential difference. This gap would change size when the cable is bent, potentially leading to unstable high-frequency characteristics. In this embodiment, the integrated braided shielding layer 5 is positioned along the outline of the shielding layer 22, thus maintaining stable high-frequency characteristics even when bent.

[0047] Alternatively, the integrated braided shielding layer 5 can also cover the entire cable core 4 in a state of contact with the outer surfaces (outer surfaces of the insulator 32) of the pair of power lines 3. The integrated braided shielding layer 5 is formed into a generally trapezoidal shape (a trapezoid with rounded corners) in a cross-sectional view perpendicular to the cable length direction. Because the integrated braided shielding layer 5 is formed into a generally trapezoidal shape as in this embodiment, the operator can easily determine where the signal transmission cable 2 and the power line 3 are located in the composite cable 1. Therefore, operability during end-of-line processing can be improved.

[0048] (Sheath 6)

[0049] The sheath 6 is designed to cover the periphery of the integrated braided shielding layer 5. The sheath 6 not only protects the cable core 4 and the integrated braided shielding layer 5, but also compresses the integrated braided shielding layer 5 inward to ensure a tight connection with the shielding layer 22.

[0050] The sheath 6 is formed to cover the periphery of the integral braided shielding layer 5, and its inner surface is formed to be approximately trapezoidal in a cross-sectional view perpendicular to the cable length direction, following the shape of the integral braided shielding layer 5. Furthermore, the outer surface of the sheath 6 is formed to be approximately circular in a cross-sectional view perpendicular to the cable length direction. In other words, the shape of the sheath 6 (the shape of the composite cable 1) is formed to be approximately circular in a cross-sectional view perpendicular to its cable length direction. The sheath 6 can be formed by insert extrusion. By forming the sheath 6 by insert extrusion, the shape of the sheath 6 can be made circular with almost no gap between the sheath 6 and the integral braided shielding layer 5. The thickness of the sheath 6 is inconsistent along the circumference of the cable. Specifically, the portion covering the edge of the integral braided shielding layer 5, which is approximately trapezoidal in a cross-sectional view perpendicular to the cable length direction (… Figure 1 The sheath 6 (the straight section in the middle) is thicker, and in the part covering the integral braided shielding layer 5, it corresponds to the corner portion ( Figure 1 The sheath 6 (the part with the four curved corners) is thinner.

[0051] By forming the sheath 6 with such a structure, the sheath 6 effectively compresses the integral braided shielding layer 5 towards the cable core 4, ensuring that even when the composite cable 1 is bent or twisted, no gap is generated between the integral braided shielding layer 5 and the shielding layer 22 (which are normally in contact). As a result, even with bent wiring, a composite cable 1 with less degradation of high-frequency characteristics can be achieved. Furthermore, by making it approximately circular as in this embodiment, a composite cable 1 that is easy to wire even in narrow wiring spaces can be achieved. It should be noted that, without impairing the effects of the present invention, the sheath 6 can also be extruded through a tube to make the formed cross-section (a cross-sectional view perpendicular to the cable length direction) approximately circular.

[0052] (The role and effects of the implementation method)

[0053] As described above, the composite cable 1 according to this embodiment includes a signal transmission cable 2, a pair of power lines 3, an integral braided shielding layer 5, and a sheath 6; the signal transmission cable 2 has a pair of signal lines 21 arranged parallel to each other in the cable length direction and arranged to contact each other, and a shielding layer 22 integrally covering the pair of signal lines 21; the pair of power lines 3 are arranged to contact each other and are respectively in contact with the shielding layer 22; the integral braided shielding layer 5 integrally covers the periphery of the cable core 4 formed by the signal transmission cable 2 and the pair of power lines 3; the sheath 6 covers the periphery of the integral braided shielding layer 5; wherein, the integral braided shielding layer 5 is arranged to follow the outline of the shielding layer 22 and be tightly connected to the shielding layer 22.

[0054] The integrated braided shielding layer 5 is tightly connected to the shielding layer 22, thereby suppressing adverse conditions such as changes in the gap size between the integrated braided shielding layer 5 and the shielding layer 22 during bending due to the presence of a shielding wire between them. This enables the composite cable 1 to achieve less degradation of high-frequency characteristics even when the wiring is bent. Furthermore, by using a two-core parallel cable as the signal transmission cable 2, differences in length between the signal lines 21 can be suppressed, thus preventing degradation of high-frequency characteristics due to skew.

[0055] Furthermore, by constructing a structure in which a pair of power lines 3 are in contact with each other and each pair of power lines 3 is in contact with the signal transmission cable 2, compared to, for example, configuring a pair of power lines to clamp the signal transmission cable 2, the diameter of the composite cable 1 can be reduced, enabling the composite cable 1 to be easily routed even in confined wiring spaces. Furthermore, by tightly connecting the integral braided shielding layer 5 to the shielding layer 22, the diameter of the composite cable 1 can be further reduced.

[0056] (Summary of Implementation Methods)

[0057] Next, the technical concepts grasped based on the embodiments described above will be described by referring to the reference numerals in the embodiments. However, the reference numerals in the following description are not intended to limit the constituent elements in the claims to the components specifically shown in the embodiments.

[0058] [1] A composite cable (1) has a signal transmission cable (2), a pair of power lines (3), an integral braided shielding layer (5), and a sheath (6); the signal transmission cable (2) has a pair of signal lines (21) configured to be parallel to each other and to be in contact with each other in the cable length direction and a shielding layer (22) integrally covering the pair of signal lines (21); the pair of power lines (3) are configured to be in contact with each other and to contact the shielding layer (22); the integral braided shielding layer (5) integrally covers the periphery of the cable core (4) formed by the signal transmission cable (2) and the pair of power lines (3); the sheath (6) covers the periphery of the integral braided shielding layer (5); wherein the integral braided shielding layer (5) is configured to be along the outline of the shielding layer (22) and to be in close contact with the shielding layer (22).

[0059] [2] According to the composite cable (1) described in [1], wherein the cable core (4) is configured such that, in a cross-sectional view perpendicular to the length of the cable, the virtual line (V) connecting the center of the pair of signal lines (21) and the center of the pair of power lines (3) is trapezoidal.

[0060] [3] The composite cable (1) according to claim [1] or [2], wherein the shielding layer (22) integrally has a pair of flat portions (22a) extending in a straight line along the arrangement direction of the pair of signal lines (21) and a pair of bent portions (22b) connecting the ends of the pair of flat portions (22a) to each other, the pair of power lines (3) being configured to contact one side of the flat portion (22a), and the integral braided shielding layer (5) being configured to closely connect the entire flat portion (22a) on the side not in contact with the pair of power lines (3) and a portion of the pair of bent portions (22b) on both sides of the flat portion (22a).

[0061] [4] The composite cable (1) according to any one of [1] to [3], wherein the pair of signal lines (21) has a signal conductor (211) and an insulator (212) surrounding the signal conductor (211), the insulator (212) having an inner insulator (212a) surrounding the signal conductor (211) and an outer insulator (212b) surrounding the inner insulator (212a), the melting point of the outer insulator (212b) being lower than the melting point of the inner insulator (212a).

[0062] [5] The composite cable (1) according to [4] is wherein the dielectric constant of the inner insulator (212a) is lower than that of the outer insulator (212b).

[0063] [6] The composite cable (1) according to any one of [1] to [5], wherein the signal transmission cable (2) further comprises a resin strip (23) spirally wound around the pair of signal lines (21), the shielding layer (22) being formed of a metal strip having a metal layer (222) formed on one side surface of the resin layer (221) and an adhesive layer (223) formed on the other side surface of the resin layer (221), and configured such that the metal strip is spirally wound around the resin strip (23) such that the adhesive layer (223) is located on one side of the resin strip (23).

[0064] The embodiments of the present invention have been described above, but these embodiments are not intended to limit the invention as defined in the claims. Furthermore, it should be noted that not all combinations of the features described in the embodiments are necessary to solve the problems of the invention.

[0065] The present invention can be modified appropriately without departing from its spirit. For example, in the above embodiment, the case where the insulator 212 of the signal line 21 is composed of two layers has been described, but the insulator 212 of the signal line 21 may also be composed of three or more layers.

Claims

1. A composite cable, comprising: A signal transmission cable having a pair of signal lines configured to be parallel to each other and in contact with each other along the length of the cable, and a shielding layer integrally covering the pair of signal lines. A pair of power lines configured to contact each other and to contact the shielding layer. An integral braided shielding layer that integrally covers the cable core formed by the signal transmission cable and the pair of power lines, and A sheath that covers the periphery of the integral braided shielding layer; The integral braided shielding layer is configured to follow the outline of the shielding layer and be tightly connected to it. The pair of signal lines have signal conductors and an insulator surrounding the signal conductors. The insulator has an inner layer insulator surrounding the signal conductor and an outer layer insulator surrounding the inner layer insulator.

2. The composite cable according to claim 1, wherein, The cable core is configured such that, in a cross-sectional view perpendicular to the cable length, the virtual line connecting the center of the pair of signal lines and the center of the pair of power lines is trapezoidal.

3. The composite cable according to claim 1 or 2, wherein, The outer diameter of the power line is smaller than that of the signal line, and the outer diameter of the power line is more than 0.5 times but less than 1 times that of the signal line. The outer diameter of the signal line is more than 1.50 mm but less than 1.80 mm, and the outer diameter of the power line is more than 1.00 mm but less than 1.50 mm.

4. The composite cable according to claim 1 or 2, wherein, The shielding layer integrally has a pair of flat portions extending in a straight line along the arrangement direction of the pair of signal lines, and a pair of curved portions connecting the ends of the pair of flat portions to each other. The pair of power lines are configured to contact the flat portion on one side. The integral braided shielding layer is configured as a flat portion that is closely connected to the side of the pair of power lines that is not in contact with the flat portion, and a portion of the pair of curved portions on both sides of the flat portion.

5. The composite cable according to claim 1 or 2, wherein, The melting point of the outer layer insulator is lower than that of the inner layer insulator.

6. The composite cable according to claim 1, wherein, The dielectric constant of the inner layer insulator is lower than that of the outer layer insulator.

7. The composite cable according to claim 5, wherein, The resin used as the inner layer insulator has a melting point of 250°C or higher and 330°C or lower, while the resin used as the outer layer insulator has a melting point of 90°C or higher and 170°C or lower.

8. The composite cable according to claim 1 or 2, wherein, The signal transmission cable also has a resin tape spirally wound around the pair of signal lines. The shielding layer is formed of a metal strip with a metal layer formed on one side surface of the resin layer and an adhesive layer formed on the other side surface of the resin layer, and is configured such that the metal strip is spirally wound around the resin strip such that the adhesive layer is located on one side of the resin strip.

9. The composite cable according to claim 8, wherein, The winding direction of the metal strip is different from the winding direction of the resin strip that forms its base.

10. The composite cable according to claim 1 or 2, wherein, No shielding wire is provided between the shielding layer and the integral braided shielding layer.

Images