Composite cable

Abstract

To provide a composite cable in which occurrence of breakage of a shield is easily suppressed.SOLUTION: In the composite cable 1 including at least one internal cable, two power supply lines 20, one ground line 30, and an external sheath 40 covering the peripheries thereof, the internal cable 10 includes two signal lines, a first sheath 15 covering the peripheries of the two signal lines, a shield 16 covering the periphery of the first sheath 15, and a second sheath 17 covering the periphery of the shield 16, the first sheath 15 is interposed between the two signal lines, and irregularities for increasing the surface roughness are provided on the outer peripheral surface thereof, the shield 16 is a braid formed by combining strands formed of a conductive metal material or a conductive metal thin film, and one inner cable 10 and one ground wire 30 are arranged in a valley between the two power wires 20 and face each other with the two power wires 20 interposed therebetween in a cross-sectional view.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a composite cable.

Background Art

[0002] In recent years, an electromechanical brake (hereinafter also referred to as EMB) device using an electric motor or the like has begun to be proposed instead of a brake device using hydraulic pressure. In addition, an electric parking brake device in which the parking brake is electrified is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an EMB device or the like, a wire for supplying power to an electric motor (also referred to as a power line) and a wire for transmitting the output of various sensors for measuring parameters such as an angle (also referred to as a signal line) are connected. These plurality of wires may be covered with a common covering member to form a composite cable. and combined.

[0005] These wires are provided with a shield such as a braid for shielding electromagnetic noise generated by themselves or electromagnetic noise generated externally, and a sheath may be provided outside the shield. The outer sheath may apply a force toward the center to deform the shield.

[0006] When the composite cable is bent in a state where the shield is deformed, local stress concentration may occur in the shield, and the shield may be damaged. When the shield is damaged, there is a problem that the ability to shield electromagnetic noise is reduced.

[0007] The present invention was made to solve the above problems and aims to provide a composite cable that is more likely to suppress shield damage. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides the following means. The present invention relates to a composite cable having at least one internal cable, two power lines, one ground wire, and an external sheath covering them, wherein the internal cable consists of two signal lines, a first sheath covering the two signal lines, a shield covering the first sheath, and a second sheath covering the shield, the first sheath is interposed between the two signal lines and has irregularities on its outer surface to increase surface roughness, the shield is a braid of strands made of conductive metal material or a conductive metallic thin film, and the one internal cable and the one ground wire are arranged in the valley between the two power lines in a cross-sectional view and face each other with the two power lines in between.

[0009] According to the composite cable of the present invention, the cross-sectional shape of the shield is less likely to deform even when the shield is subjected to an inward force from the second sheath. Furthermore, even when the composite cable is bent, localized stress concentration in the shield is less likely to occur.

[0010] Furthermore, the shield is less likely to come into direct contact with other cables (such as two power lines or one ground wire). As a result, the shield is less likely to slide against other cables and damage them. [Effects of the Invention]

[0011] According to the composite cable of the present invention, localized stress concentration is less likely to occur in the shield even when bent, thus effectively suppressing shield damage. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view illustrating the configuration of the composite cable in this embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, a composite cable 1 according to one embodiment of the present invention will be described with reference to Figure 1. In this embodiment, the description will be applied to an example where the composite cable 1 is a cable used in an EMB device. However, the composite cable 1 may also be used in devices other than an EMB device.

[0014] Figure 1 is a cross-sectional view illustrating the configuration of the composite cable 1 of this embodiment. As shown in Figure 1, the composite cable 1 is provided with one internal cable 10, two power lines 20, 20, one ground wire 30, and an external sheath (corresponding to a covering member) 40.

[0015] The internal cable 10 may consist of two or more wires. The power lines 20,20 may consist of one wire or three or more wires. The ground wire 30 may consist of two or more wires.

[0016] The internal cable 10 is a signal line that propagates electrical signals output from various sensors installed in the EMB device, as well as electrical signals used in CAN (Controller Area Network). Examples of various sensors include load sensors and angle sensors.

[0017] The internal cable 10 is provided with two twisted wires 11, 11, a first sheath 15 that surrounds the two wires 11, 11, a shield 16, and a second sheath 17. The first sheath 15 is interposed between the two wires 11.

[0018] The wire 11 is a signal line that is conductively connected to the sensor. The two wires 11, 11 are in contact and twisted together. In this embodiment, an example in which the two wires 11, 11 have the same configuration will be described. The wire 11 is provided with a conductor 12 and a sheath 13 that covers the periphery of the conductor 12.

[0019] The conductor 12 is a member formed in a long shape, and is a member obtained by twisting a plurality of metal strands having conductivity, such as copper or an alloy containing copper as a component. The cross section of the conductor 12 may be circular, elliptical, or rectangular.

[0020] The sheath 13 is a member formed from a resin material that covers the periphery of the conductor 12 in a layered manner. A known resin can be used as the resin for forming the sheath 13, and the type is not particularly limited.

[0021] The first sheath 15 is a member formed from a resin material that covers the periphery of the two wires 11, 11. The first sheath 15 is also a member that supports the shield 16. The first sheath 15 is a member formed in a columnar shape having a solid configuration that includes the two wires 11, 11 inside.

[0022] The cross section of the first sheath 15 preferably has a shape in which the stress acting on the shield 16 is dispersed when the composite cable 1 is bent. Specifically, it is preferable that all sides of the cross section are composed of curves. In this embodiment, an example in which the cross section of the first sheath 15 is a columnar member that is substantially circular or substantially elliptical will be described.

[0023] On the outer peripheral surface of the first sheath 15, irregularities for increasing the surface roughness are provided. As a processing method for forming the irregularities, embossing can be used in which a plate provided with irregularities is pressed against the outer peripheral surface of the first sheath 15. The surface roughness can be exemplified by 3 μm.

[0024] The resin material constituting the first sheath 15 is a flame-retardant-free resin material that has higher flexibility at low temperatures compared to the flame-retardant-containing resin material constituting the second sheath 17, which will be described later. The resin material constituting the first sheath 15 is a resin material with a Shore D hardness of 80 or less. For example, urethane rubber or silicone rubber can be used.

[0025] The shield 16 is an electromagnetic noise shielding component placed on the outer surface of the first sheath 15. The electromagnetic noise may be generated by the power flowing through the electric wire 11, or it may be generated outside the internal cable 10.

[0026] In this embodiment, the shield 16 will be described in the example where it is a braid made of wires formed from a conductive metallic material. For example, the shield 16 will be described in the example where it is a copper foil braid. The shield 16 may also be a thin metallic film that is conductive.

[0027] The second sheath 17 is a component formed from a resin material that surrounds the shield 16. The second sheath 17 is a component having a tubular structure formed in layers along the outer surface of the shield 16.

[0028] The outer surface of the second sheath 17 is provided with irregularities to increase surface roughness. As a processing method for forming the irregularities, embossing can be used, in which a plate with irregularities is pressed against the outer surface of the second sheath 17. An example of a surface roughness is 3 μm.

[0029] The resin material constituting the second sheath 17 contains a flame retardant. The resin material used for the second sheath 17 has a Shore D hardness of 90 or less. For example, polyethylene resin, fluororesin, or ethylene-propylene-diene rubber (also known as EPDM) are used.

[0030] Examples of flame retardants used in the second sheath 17 include silica (silicon dioxide), metal hydroxides (magnesium hydroxide, aluminum hydroxide), brominated flame retardants, phosphoric acid-based flame retardants, nitrogen-based flame retardants, and combinations of brominated flame retardants and antimony trioxide. In this embodiment, an example using silica as a flame retardant will be described.

[0031] Furthermore, the wires 11 provided in the internal cable 10 may be two or three or more, as described above. In addition, the wires 11 provided in the internal cable 10 may be just one.

[0032] The two power lines 20, 20 are power lines that supply power to electric motors and actuators installed in the EMB device. Power line 20 is provided with a conductor 21 and a sheath 22.

[0033] The conductor 21 is a long, rectangular member formed by twisting together multiple conductive metal wires, such as copper or an alloy containing copper. The cross-section of the conductor 21 may be circular, elliptical, or rectangular.

[0034] The sheath 22 is a component formed from a resin material that covers the conductor 21 in layers. A known resin can be used to form the sheath 22, and there are no particular limitations on the type.

[0035] One ground wire 30 is an electric wire used for grounding. The ground wire 30 is provided with a conductor 31 and a sheath 32. In this embodiment, the explanation applies to an example in which a ground wire 30 is provided on the composite cable 1, but the composite cable 1 does not necessarily have to be provided with a ground wire 30.

[0036] The conductor 31 is a long, elongated member formed by twisting together multiple conductive metal strands, such as copper or an alloy containing copper. The cross-section of the conductor 31 may be circular, elliptical, or rectangular.

[0037] The sheath 32 is a component formed from a resin material that covers the conductor 31 in layers. A known resin can be used to form the sheath 32, and there are no particular limitations on the type.

[0038] The outer sheath 40 is a component formed from a resin material that layers around one internal cable 10, two power lines 20, 20, and one ground wire 30. A known resin can be used to form the outer sheath 40, and there are no particular limitations on the type of resin.

[0039] In the composite cable 1 with the above configuration, by arranging the electric wires 11, 11, the first sheath 15, the shield 16, and the second sheath 17 in that order, the shield 16 is supported by the first sheath 15 which is located on the electric wire 11 side. Even if the shield 16 is subjected to a force directed from the second sheath 17 toward the electric wire 11 side, the cross-sectional shape of the shield 16 is less likely to deform. Furthermore, even if the composite cable 1 is bent, localized stress concentration in the shield 16 is less likely to occur, making it easier to suppress damage to the shield 16.

[0040] By providing the second sheath 17, direct contact between the shield 16 and the power lines 20, 20, etc., is made less likely. As a result, the power lines 20, 20, etc., are less likely to be damaged by sliding against the shield 16.

[0041] The inclusion of a flame retardant in the material forming the second sheath 17 makes it easier to provide heat resistance to the internal cable 10. By increasing the flexibility of the first sheath 15 compared to the second sheath 17, the internal cable 10 becomes less susceptible to damage. For example, when the composite cable 1 is bent, the first sheath 15 bends more significantly, and therefore the first sheath 15 is less likely to be damaged.

[0042] By forming the first sheath 15 using a material with lower hardness than the second sheath 17, the internal cable 10 becomes less susceptible to damage. For example, when the composite cable 1 is bent, the first sheath 15, which bends more significantly, is less susceptible to damage because of its lower hardness.

[0043] By providing the outer surface of the first sheath 15 with irregularities to increase surface roughness, the first sheath 15 and the shield 16 can move relative to each other more easily. By providing the outer surface of the second sheath 17 with irregularities to increase surface roughness, the inner cable 10 and the outer sheath 40 can move relative to each other more easily. As a result, when the composite cable 1 is bent, strain is less likely to occur in the conductor 12 of the electric wire 11 that is located inside the first sheath 15.

[0044] The first sheath 15 may be constructed using foamed polyethylene that does not contain flame retardants, instead of urethane rubber or silicone rubber. In this case, the resin material constituting the second sheath 17 is not foamed.

[0045] By using foamed polyethylene, multiple voids can be created inside the first sheath 15. This makes it easier to lower the dielectric constant of the first sheath 15. By lowering the dielectric constant of the first sheath 15, the characteristic impedance can be reduced, making it easier to reduce the loss of current flowing through the conductor 12.

[0046] The wire 11 of the internal cable 10 may be a signal wire that is electrically connected to the sensor as described above, a drain wire inside the first sheath 15, or a power wire that supplies power to the equipment.

[0047] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the present invention is not limited to those applied to the embodiments described above, but may also be applied to embodiments that combine these embodiments as appropriate, and is not particularly limited. [Explanation of Symbols]

[0048] 1…Composite cable, 10…Internal cable, 11…Electric wire, 12…Conductor, 15…First sheath, 16…Shield, 17…Second sheath, 40…Outer sheath (covering material)

Claims

1. In a composite cable having at least one internal cable, two power lines, one ground wire, and an external sheath covering these, The internal cable comprises two signal wires, a first sheath surrounding the two signal wires, a shield surrounding the first sheath, and a second sheath surrounding the shield. The first sheath is positioned between the two signal lines, and its outer surface is provided with irregularities to increase surface roughness. The shield is a braid of wires formed from conductive metallic materials, or a conductive metallic thin film. The aforementioned internal cable and the aforementioned ground wire are positioned in the valley between the two power lines in a cross-sectional view, and are opposite each other with the two power lines in between. Composite cable.

2. The second sheath is formed using a material containing a flame retardant. The composite cable according to claim 1.

3. The first sheath has greater flexibility than the second sheath. The composite cable according to claim 1 or 2.

4. The first sheath is formed using a material with lower hardness than the second sheath. The composite cable according to claim 1.

5. The second sheath is provided with irregularities that increase the surface roughness of the outer surface. The composite cable according to claim 1.

6. Multiple voids are provided inside the first sheath. The composite cable according to claim 1.

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