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 technology]

[0002] In recent years, electro mechanical brake (hereinafter also referred to as EMB) devices that use electric motors or the like instead of hydraulic brake devices have begun to be proposed. Also, an electric parking brake device in which the parking brake is electrically operated is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-077632 Summary of the Invention [Problem to be solved by the invention]

[0004] EMB devices and the like are connected with wires (also called power lines) that supply power to electric motors, and wires (also called signal lines) that transmit the output of various sensors that measure parameters such as angles. These multiple wires are covered with a common covering material and are called a composite cable. This may be the case.

[0005] These electric wires are sometimes provided with a shield such as a braid to block electromagnetic noise generated by the wire itself and electromagnetic noise generated externally, and a sheath is sometimes provided around the shield. The outer sheath can apply a force toward the center to the shield, causing it to deform.

[0006] If the composite cable is bent while the shield is deformed, stress may be concentrated locally on the shield, potentially damaging it, which in turn reduces its ability to block electromagnetic noise.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a composite cable in which the occurrence of damage to the shield can be easily suppressed. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides the following means. The present invention relates to a composite cable having at least one inner cable, two power wires, and one earth wire, and an outer sheath surrounding these, wherein the inner 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 extends between the two signal wires and has an outer surface with irregularities to increase surface roughness, the shield is a braid made of wires formed from a conductive metal material or a thin conductive metal film, and the one inner cable and the one earth wire are arranged in a valley between the two power wires in a cross-sectional view and face each other with the two power wires 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, local stress concentration is less likely to occur in the shield.

[0010] It also reduces the chance of direct contact between the shield and other cables (two power lines or one earth line), which reduces the risk of the shield sliding against other cables and damaging them. [Effects of the Invention]

[0011] According to the composite cable of the present invention, even when the cable is bent, localized stress concentration is unlikely to occur in the shield, and damage to the shield can be easily suppressed. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view illustrating the configuration of a composite cable according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] A composite cable 1 according to one embodiment of the present invention will be described below with reference to Fig. 1. In this embodiment, the composite cable 1 is described as an example of a cable used in an EMB device. Note that the composite cable 1 may also be used in devices other than an EMB device.

[0014] Fig. 1 is a cross-sectional view illustrating the configuration of a composite cable 1 of this embodiment. As shown in Fig. 1, the composite cable 1 includes one inner cable 10, two power wires 20, 20, one earth wire 30, and an outer sheath (corresponding to a covering member) 40.

[0015] The number of internal cables 10 may be two or more. The number of power lines 20, 20 may be one or three or more. The number of earth lines 30 may be two or more.

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

[0017] The inner cable 10 includes two twisted electric wires 11, 11, a first sheath 15 that covers the two electric wires 11, 11, a shield 16, and a second sheath 17. The first sheath 15 is inserted between the two electric wires 11.

[0018] The electric wire 11 is a signal wire electrically connected to the sensor. The two electric wires 11 are in contact with each other and twisted together. In this embodiment, the two electric wires 11 have the same configuration. The electric wire 11 includes a conductor 12 and a sheath 13 that covers the conductor 12.

[0019] Conductor 12 is a long member formed by twisting together a plurality of conductive metal wires such as copper or a copper-containing alloy, etc. The cross section of 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 form. Any known resin can be used as the resin for forming the sheath 13, and there is no particular limitation on the type.

[0021] The first sheath 15 is a member made of a resin material that covers the two electric wires 11, 11. The first sheath 15 is also a member that supports the shield 16. The first sheath 15 is a columnar member that has a solid structure that contains the two electric wires 11, 11 inside.

[0022] The cross section of the first sheath 15 preferably has a shape that disperses the stress acting on the shield 16 when the composite cable 1 is bent. Specifically, it is preferable that all sides of the cross section are curved. In this embodiment, the first sheath 15 is described as a columnar member having a cross section that is approximately circular or approximately elliptical.

[0023] The outer peripheral surface of the first sheath 15 is provided with irregularities to increase the surface roughness. As a processing method for forming the irregularities, embossing can be used, in which an irregular plate is pressed against the outer peripheral surface of the first sheath 15. The surface roughness can be, for example, 3 μm.

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

[0025] The shield 16 is a member that blocks electromagnetic noise and is disposed on the outer circumferential surface of the first sheath 15. The electromagnetic noise may be generated by the power flowing through the electric wire 11, or may be generated outside the inner cable 10.

[0026] In this embodiment, the shield 16 is described as being a braid made of wires formed from a conductive metal material. For example, the shield 16 is described as being a braid made of copper foil thread. However, the shield 16 may also be a thin conductive metal film.

[0027] The second sheath 17 is a member made of a resin material that covers the periphery of the shield 16. The second sheath 17 is a member that has a tubular configuration and is formed in layers along the outer peripheral surface of the shield 16.

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

[0029] A flame retardant is contained in the resin material that constitutes the second sheath 17. A resin material having a Shore D hardness of 90 or less is used as the resin material that constitutes the second sheath 17. For example, polyethylene resin, fluororesin, or ethylene propylene diene rubber (also written as EPDM) is used.

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

[0031] The number of electric wires 11 provided in the internal cable 10 may be two as described above, or may be three or more. Furthermore, the number of electric wires 11 provided in the internal cable 10 may be one.

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

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

[0034] The sheath 22 is a member made of a resin material that covers the periphery of the conductor 21 in a layered form. Any known resin can be used as the resin for forming the sheath 22, and the type is not particularly limited.

[0035] The single earth wire 30 is an electric wire used for grounding. The earth wire 30 includes a conductor 31 and a sheath 32. Note that, although the present embodiment will be described as being applied to an example in which the earth wire 30 is provided in the composite cable 1, the earth wire 30 does not necessarily have to be provided in the composite cable 1.

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

[0037] The sheath 32 is a member made of a resin material that covers the periphery of the conductor 31 in a layered form. Any known resin can be used as the resin for forming the sheath 32, and there is no particular limitation on the type.

[0038] The outer sheath 40 is a member formed from a resin material that covers the inner cable 10, the power wires 20, 20, and the earth wire 30 in a layered manner. Any known resin can be used as the resin for forming the outer sheath 40, and there are no particular limitations on the type.

[0039] According to the composite cable 1 having the above configuration, by arranging the electric wires 11, 11, the first sheath 15, the shield 16, and the second sheath 17 in this order, the shield 16 is supported by the first sheath 15 arranged on the electric wire 11 side. Even if the shield 16 receives a force from the second sheath 17 toward the electric wire 11 side, the cross-sectional shape of the shield 16 is unlikely to deform. Furthermore, even if the composite cable 1 is bent, local stress concentration is unlikely to occur in the shield 16, making it easier to suppress damage to the shield 16.

[0040] By providing the second sheath 17, it becomes difficult for the shield 16 to come into direct contact with the power wires 20, 20, etc. Therefore, the power wires 20, 20, etc. are less likely to be damaged by the shield 16 sliding against the power wires 20, 20, etc.

[0041] By including a flame retardant in the material forming the second sheath 17, it becomes easier to provide the inner cable 10 with heat resistance. By increasing the flexibility of the first sheath 15 relative to the second sheath 17, the inner cable 10 is less likely to be damaged. For example, when the composite cable 1 is bent, the first sheath 15 bends more greatly and has a higher flexibility, so the first sheath 15 is less likely to be damaged.

[0042] By forming the first sheath 15 using a material that is lower in hardness than the second sheath 17, the inner cable 10 is less likely to be damaged. For example, when the composite cable 1 is bent, the first sheath 15 is bent more greatly and has a lower hardness, so the first sheath 15 is less likely to be damaged.

[0043] Providing irregularities that increase the surface roughness on the outer peripheral surface of the first sheath 15 facilitates relative movement between the first sheath 15 and the shield 16. Providing irregularities that increase the surface roughness on the outer peripheral surface of the second sheath 17 facilitates relative movement between the inner cable 10 and the outer sheath 40. Therefore, when the composite cable 1 is bent, strain is less likely to occur in the conductor 12 of the electric wire 11 arranged inside the first sheath 15.

[0044] The first sheath 15 may be made of foamed polyethylene that does not contain a flame retardant, instead of urethane rubber or silicone rubber. In this case, the resin material that makes up the second sheath 17 is not foamed.

[0045] By using foamed polyethylene, multiple pores can be formed inside the first sheath 15. This makes it easier to reduce the dielectric constant of the first sheath 15. By reducing the dielectric constant of the first sheath 15, it is easier to reduce the characteristic impedance and the loss of the current flowing through the conductor 12.

[0046] The electric 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 within the first sheath 15, or a power supply wire that supplies power to the device.

[0047] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, the present invention is not limited to applications of the above-described embodiments, and may be applied to embodiments in which these embodiments are appropriately combined, and is not particularly limited. [Explanation of symbols]

[0048] 1...Composite cable, 10...Inner cable, 11...Electric wire, 12...Conductor, 15...First sheath, 16...Shield, 17...Second sheath, 40...Outer sheath (coating member)

Claims

1. A composite cable having at least one inner cable, two power lines, one earth line, and an outer sheath surrounding these, the inner cable includes two signal lines, a first sheath that surrounds the two signal lines, a shield that surrounds the first sheath, and a second sheath that surrounds the shield; the first sheath is inserted between the two signal wires and has an outer circumferential surface provided with irregularities that increase surface roughness; the shield is a braid made of wires formed from a conductive metal material, or a thin conductive metal film; the one internal cable and the one earth wire are arranged in a valley between the two power supply wires in a cross-sectional view and are opposed to each other with the two power supply wires interposed therebetween; 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 higher flexibility than the second sheath. The composite cable according to claim 1 or 2.

4. The first sheath is formed using a material having a 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 circumferential surface. The composite cable according to claim 1.

6. A plurality of holes are provided inside the first sheath. The composite cable according to claim 1.

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