JP2021082822A - cable - Google Patents

Abstract

To provide a cable excellent in electromagnetic wave shielding property, while eliminating the need for a shield conductor such as a metal braid.SOLUTION: A cable 1 according to the present invention is provided with, on the outer periphery of a core part 4 made up of a power source line 2 and a signal line 3, a coating layer 5 including a shield layer 51 formed by a resin composition obtained by mixing conductive filler with thermoplastic resin. Meanwhile, the cable 1 does not require a shield conductor such as a metal braid. As a result, the shield layer 51 blocks (shields) external noise and so forth, thus allowing excellent electromagnetic wave shielding property of the cable 1, while eliminating the need for the shield conductor. In addition, the present invention also solves problems during manufacture of the cable 1 as well as during terminal processing work.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cable. More specifically, the present invention relates to a cable used as a cable for an electric brake of an automobile or the like.

In recent years, electric brakes (electric brakes) that electrically control brakes and systems using them have been applied to brakes for automobiles and the like, instead of hydraulic brakes. In this system, an electric brake cable for supplying electric power to a motor for operating a brake or the like and transmitting an operation signal or the like is required. Such an electric brake cable is connected to the vehicle body side and the caliper (brake caliper) side via terminals, respectively.

The electric brake cable described above requires, for example, a plurality of power supply lines and signal lines as power supply lines and lead wires for various sensors as signal lines. Further, the power supply line and the signal line are twisted to form a multi-core stranded wire to form a core portion, and the outer circumference of the core portion is covered with a sheath made of a thermoplastic resin or the like.

On the other hand, various cables are used in automobiles, but in recent automobiles, electrification including the above-mentioned brakes is progressing, and various inverters and many electronic information devices are installed. Therefore, there is a noise source inside the automobile, and electromagnetic noise or the like generated from the noise source is radiated (radiated) through the cable, which may adversely affect various electronic information devices and control devices. In addition, electromagnetic noise may be mixed into various electronic information devices, control devices, and the like via cables, causing malfunctions in these devices, which has been a problem.

Due to the above problems, the cable must have a shielding property (electromagnetic wave shielding property) as a countermeasure against electromagnetic wave noise of the cable. For example, a shield such as a metal braid (braided shield) composed of a braided metal wire. Generally, a conductor is wound around the outer periphery of the core portion, and the periphery of a metal braid or the like is sheathed with heat-resistant vinyl, urethane, or the like to cover it (see, for example, Patent Document 1 and the like).

Japanese Unexamined Patent Publication No. 2006-351322

In general, by connecting a shield conductor to the ground potential of a cable having the above-mentioned structure, it is possible to suppress the mixing of electromagnetic noise from the outside into the power supply line of the core and the radiation of electromagnetic noise from the cable to the outside of the cable. Or will be prevented. However, manufacturing a cable by covering the outer periphery of the core portion consisting of a power supply line and a signal line with a shield conductor made of a metal braid or the like is complicated, and in addition, the shield conductor is used during terminal processing work. There was a problem such as getting in the way. Therefore, it has been desired to develop a cable that does not require a shield conductor such as a metal braid.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a cable having good electromagnetic wave shielding property while not requiring a shield conductor such as a metal braid.

In order to solve the above-mentioned problems, the cable according to the present invention is a cable in which a coating layer is provided on the outer periphery of a core portion formed by twisting a plurality of power supply lines and a plurality of signal lines, and the coating layer is at least The thickness is composed of two layers, and at least one of the coating layers is a resin composition obtained by mixing a thermoplastic resin with at least one conductive filler from the group consisting of carbon black, carbon nanotubes, and metal nanoparticles. Is a shield layer of 0.2 to 0.5 mm, and the thermoplastic resin is at least one of the group consisting of an ethylene-vinyl acetate copolymer and an ethylene-acrylic acid ester copolymer, and the shield layer. The volume specific resistance of the above is 3 × 10 ³ Ω · cm or more and 1 × 10 ¹⁴ Ω · cm or less.

The cable according to the present invention is characterized in that, in the present invention, the content of the conductive filler in the resin composition is 10 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

The cable according to the present invention is characterized in that, in the present invention described above, the outermost layer of the coating layer is not the shield layer, but the outermost layer is made of a polyurethane resin.

The cable according to the present invention is characterized in that, in the present invention, the coating layer (excluding the shield layer) is a flame-retardant crosslinked resin material.

The cable according to the present invention is characterized in that, in the present invention described above, the coating layer contains a metal hydrate.

The cable according to the present invention is characterized in that, in the present invention described above, the shielding effect (dB) when the frequency of electromagnetic noise is 20 MHz is 42 to 45 dB.

In the cable according to the present invention, a coating layer including a shield layer made of a resin composition in which a conductive filler is mixed with a thermoplastic resin is formed on the outer periphery of a core portion consisting of a power supply line and a signal line, and a metal braid or the like is formed. The configuration does not require the shield conductor of. Therefore, the shield layer shields (shields) noise and the like from the outside, and the cable has good electromagnetic wave shielding properties while not requiring a shield conductor. In addition, problems during cable manufacturing and terminal processing work are also eliminated.

It is sectional drawing which showed an example of the structure of the cable which concerns on this invention.

(1) Structure of cable 1:
Hereinafter, one aspect of the present invention will be described. FIG. 1 is a cross-sectional view showing an example of the structure of the cable 1 according to the present invention. In FIG. 1, 1 is a cable, 2 is a power line, 3 is a signal line, 21 and 31 are conductors, 22 and 32 are insulating layers, 4 is a core portion, 5 is a coating layer, 51 is a shield layer, and 52 is an outermost layer. , Are shown respectively.

In the cable 1 according to the present invention shown in FIG. 1, a coating layer 5 is provided on the outer periphery of a core portion 4 composed of a multi-core stranded wire obtained by twisting a power supply line 2 and a signal line 3, and the coating layer 5 is at least As a basic configuration, it is composed of two layers (plurality of layers), and at least one layer of the coating layer 5 is provided with a shield layer 51 made of a resin composition in which a conductive filler is mixed with a thermoplastic resin. On the other hand, the cable 1 according to the present invention does not include a shield conductor such as a metal braid as a configuration.

(2) Power supply line 2 and signal line 3 (core unit 4):
The power supply line 2 is provided for the purpose of supplying electric power to a motor (not shown) that operates an electric brake. Further, the signal line 3 is provided for the purpose of transmitting and communicating an operation signal, and the signal line 3 is used as a lead wire for various sensors and the like.

An ABS (Antilock Brake System) sensor, which is known as a sensor mounted on an automobile or the like, measures the rotation speed of a wheel of the automobile or the like, and the sensor unit is generally provided in the vicinity of the wheel. Further, the sensor unit provided in the vicinity of the wheels of the automobile and the control device provided on the vehicle body side are connected by an ABS sensor cable. In the present invention, a part or all of the signal line 3 may be used as an ABS sensor cable.

The power supply line 2 includes a plurality of conductors 21 having an insulating layer 22, and the configuration shown in FIG. 1 shows a configuration in which two power supply lines 2 exist. For the conductor 21, for example, a single wire or a stranded wire such as annealed copper, an alloy containing copper (copper alloy), an alloy containing tin (tin alloy), or aluminum can be used, and the conductor 21 is plated by tin plating or the like in addition to a bare wire. You may use the alloy. The material constituting the insulating layer 22 is, for example, flame-retardant cross-linked polyethylene (flame-retardant XLPE), cross-linked polyethylene (XLPE), tetrafluoroethylene-ethylene copolymer (ETFE), polypropylene (PP), or other thermoplastic. It can be elastomer (TPE) or the like.

The signal line 3 includes a plurality of conductors 31 having an insulating layer 32, and the configuration of FIG. 1 shows a configuration in which two signal lines 3 exist. For the conductor 31, for example, a single wire or a stranded wire such as annealed copper, an alloy containing copper (copper alloy), an alloy containing tin (tin alloy), or aluminum can be used, and the conductor 31 is plated by tin plating or the like in addition to the bare wire. You may use the alloy. The material constituting the insulating layer 32 is, for example, flame-retardant cross-linked polyethylene (flame-retardant XLPE), cross-linked polyethylene (XLPE), tetrafluoroethylene-ethylene copolymer (ETFE), or a thermoplastic elastomer. Can be done.

The size and configuration of the conductors 21 and 31 in the power supply line 2 and the signal line 3 are not particularly limited, and a configuration suitable for the power supply line 2 and the signal line 3 can be appropriately selected and used regardless of whether it is a single wire or a stranded wire. it can. The thickness of the insulating layers 22 and 32 in the power supply line 2 and the signal line 3 is not particularly limited and can be formed as a desired thickness, but is preferably 0.2 to 0.4 mm. The outer diameter of the power supply line 2 and the signal line 3 is preferably 1.2 to 3.2 mm.

The power supply line 2 and the signal line 3 are easily manufactured by, for example, using a general-purpose extrusion molding machine and extruding the materials constituting the insulating layers 22 and 32 on the outer circumferences of the conductors 21 and 31. be able to.

In the cable 1 according to the present invention, the power supply line 2 and the signal line 3 described above are twisted into a multi-core stranded wire to form a core portion 4 in which the power supply line 2 and the signal line 3 are integrated. Then, the coating layer 5 is formed on the outer periphery of the core portion 4. The twist pitch length for twisting the power supply line 2 and the signal line 3 is not particularly limited, and the twist pitch length may be appropriately selected within a range in which the power supply line 2 and the signal line 3 can be integrated. It may be within the range of 40 mm. The power supply lines 2 and the signal lines 3 may be twisted in advance.

(3) Coating layer 5:
In the present invention, the coating layer 5 formed on the outer periphery of the core portion 4 is composed of at least two layers, and at least one of them is composed of a resin composition in which a conductive filler is mixed with a thermoplastic resin. Shield layer 51. In FIG. 1, a shield layer 51 is formed on the outer periphery of the core portion 4, and an outermost layer 52 (the shield layer 51 is inside the outermost layer 52) composed of layers other than the shield layer 51 is present on the outer periphery of the shield layer 51. ) Is formed.

The shield layer 51 is made of a resin composition in which a conductive filler is mixed with a thermoplastic resin. In the present invention, the shield layer 51 made of such a resin composition is used to provide the cable 1 with a shielding effect, but a shield conductor such as a metal braid is not used. Here, the "shield layer 51" in the present invention is, for example, "a resin composition obtained by mixing a conductive filler with a thermoplastic resin, and constitutes a coating layer 5 for coating the core portion 4 from the outside. A layer having a shielding effect that can shield (shield) noise, etc., and generally has a volume resistivity of 1 × 10 ¹⁴ Ω · cm or less (preferably 5 × 10 ¹³ Ω · cm or less). Is interpreted as "a layer that is." The volume resistivity (volume resistivity) of the shield layer 51 (resin composition constituting the shield layer 51) can be measured according to, for example, JIS C 2139 (solid electrical insulating material-method for measuring volume resistivity and surface resistivity). Good.

As the thermoplastic resin constituting the shield layer 51, for example, those having good heat resistance, weather resistance, oil resistance, etc. are preferable, and a cable coating material generally used as a cable used for automobiles and the like is used. Can be, for example, ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), ethylene-butyl acrylate copolymer (EA). Ethylene-acrylic acid ester copolymers such as EBA), ethylene-acrylic acid copolymers (EAA), ethylene-α-olefin copolymers and the like can be used. Further, for example, a rubber material (thermoplastic elastomer) such as ethylene propylene diene rubber, styrene butadiene rubber, butyl rubber, nitrile rubber, and chloroprene rubber, a polyurethane resin, or the like may be used. One of these thermoplastic resins may be used alone, or two or more thereof may be used in combination. Further, the thermoplastic resin is at least one kind in the group consisting of an ethylene-vinyl acetate copolymer and an ethylene-acrylic acid ester copolymer from the viewpoints of good flexibility, easy cross-linking and imparting flame retardancy, and the like. Is preferable.

Here, examples of the above-mentioned ethylene-α-olefin copolymer include ethylene and propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene and the like. Copolymers with at least one of α-olefins can be mentioned.

Further, the conductive filler mixed and dispersed with the thermoplastic resin is used to impart conductivity to the shield layer 51, and examples of the conductive filler include carbon black and carbon nanofibers having conductivity (ki). Carbon-based materials such as phase-growth carbon fiber (Vapor Green Carbon Fiber: VGCF), carbon nanotubes, carbon nanohorns, etc., Au (gold), Pt (platinum), Pd (palladium), Ag (silver), Cu (copper) ), Metal particles such as Ni (nickel), metal materials such as metal nanoparticles, and the like can be used. These conductive fillers may be used alone or in combination of two or more. Further, the conductive filler is preferably at least one of carbon black, carbon nanotubes and metal nanoparticles.

As for the size of the conductive filler, for example, if it is in the form of particles (including powder), for example, it is preferable to use one having an average primary particle diameter of approximately 0.01 to 0.08 μm. It is not limited to this.

The content of the conductive filler in the resin composition constituting the shield layer 51 is appropriately determined depending on the type, shape, size, etc. of the conductive filler, the type of the thermoplastic resin, etc., but is generally 100 parts by mass of the thermoplastic resin. It is preferably 10 to 20 parts by mass. By setting the content of the conductive filler in such a range, the required conductivity can be imparted to the shield layer 51, and for example, the volume resistivity can be approximately 1 × 10 ¹⁴ Ω · cm or less (preferably 5 × 10). ¹³ Ω · cm or less.) On the other hand, if the content of the conductive filler is less than 10 parts by mass, the shield layer 51 cannot be formed without imparting sufficient conductivity, and the shielding effect may not be exhibited, and the content of the conductive filler is 20 mass by mass. If it exceeds the portion, the content becomes excessive with respect to the thermoplastic resin, which may cause problems such as poor moldability, insufficient coating, and poor flexibility.

Since the coating layer 5 is formed of at least two layers (plurality of layers), the coating layer 5 has a layer other than the shield layer 51. As the layer other than the shield layer 51, for example, one kind or two or more kinds of thermoplastic resins constituting the shield layer 51 can be used.

In the present invention, it is preferable that the shield layer 51 is not the outermost layer 52. By not setting the shield layer 51 as the outermost layer 52, a layer that protects the shield layer 51 exists around the shield layer 51, and the shield layer 51 is appropriately protected. The resin material constituting the outermost layer 52 is a polyurethane-based resin in that it has good protection and flexibility in addition to low temperature, flexibility, abrasion resistance and other mechanical strength among the above-mentioned thermoplastic resins. It is preferably formed from a resin, and particularly preferably from a flame-retardant crosslinked polyurethane.

The thickness of the coating layer 5 is preferably about 0.5 to 0.9 mm. Of the coating layer 5, the thickness of the shield layer 51 is preferably approximately 0.2 to 0.5 mm in order to efficiently exert the shielding effect. When the outermost layer 52 is formed of a layer other than the shield layer 51, the thickness of the outermost layer 52 is preferably about 0.2 to 0.5 mm. The outer diameter of the cable 1 is preferably approximately 6.0 to 9.0 mm.

The resin materials constituting the power supply lines 2 and the insulating layers 22 and 32 of the signal lines 3 and the coating layer 5 of the cable 1 (excluding the shield layer 51) according to the present invention are flame-retardant. Bridged materials (for example, flame-retardant cross-linked polyethylene as the insulating layers 22 and 32, flame-retardant cross-linked polyurethane as the outermost layer 52 of the coating layer 5 and the like) may be used. By cross-linking the coating layer 5 and the like, not only the heat resistance can be improved but also the flame retardancy can be improved, such as not melting due to heat radiation from the brake.

In the cross-linking treatment, the conductors 21 and 31 and the core portion 4 of the resin material may be coated and then cross-linked by electron beam irradiation. As the cross-linking method, a conventional electron beam irradiation cross-linking method, a chemical cross-linking method, or the like can be adopted. In the case of the electron beam irradiation cross-linking method, cross-linking can be performed by irradiating the layer to be cross-linked with an electron beam by a conventional method after coating. On the other hand, in the case of the chemical cross-linking method, an organic peroxide or the like is added as a conventionally known cross-linking agent to the constituent materials of the insulating layers 22 and 32 and the coating layer 5, and after molding, the layer to be cross-linked is heated by a conventional method. It may be treated and crosslinked.

Further, in order to impart flame retardancy to the resin material, metal hydrates (aluminum hydroxide, magnesium hydroxide, calcium hydroxide, zirconium hydride, etc.) are used as constituent materials of the insulating layers 22 and 32 and the coating layer 5. ) Etc. may be mixed and bridged if necessary.

The resin materials constituting the insulating layers 22 and 32 and the coating layer 5 of the cable 1 according to the present invention include various additives generally used in coating materials such as electric wires and cables, for example, oxidation. An inhibitor, a metal deactivator, a flame retardant, a flame retardant aid, a filler, a lubricant and the like can be appropriately blended as optional components as long as the object of the present invention is not impaired. The following optional components may be used alone or in combination of two or more. Further, additives, resins and the like other than those listed here may be added as long as the object of the present invention is not impaired.

In order to manufacture the cable 1 of the present invention, a desired number of power supply lines 2 and signal lines 3 are twisted to form a multi-core stranded wire, and the outer periphery of the core portion 4 composed of the multi-core stranded wire is, for example, a general-purpose cable. It can be easily manufactured by extrusion-coating the coating layer 5 composed of at least two layers including the shield layer 51 by extrusion molding using an extrusion molding machine.

The cable 1 according to the present invention may be used as a harness (not shown) provided with the cable 1. In the harness, the power supply line 2 and the signal line 3 are branched at the end of the cable 1 according to the present invention, and a connector for connection (not shown) is provided at at least one end of the branched power supply line 2 and the signal line 3. It may be configured by providing or the like.

(4) Effect of the present invention:
The cable 1 according to the present invention described above includes a coating layer 5 including a shield layer 51 made of a resin composition in which a conductive filler is mixed with a thermoplastic resin on the outer periphery of a core portion 4 composed of a power supply line 2 and a signal line 3. On the other hand, it does not require a shield conductor such as a metal braid. Therefore, the shield layer 51 shields (shields) noise and the like from the outside, and the cable 1 has a good electromagnetic wave shielding property while not requiring a shield conductor. In addition, problems during the manufacturing of the cable 1 and the terminal processing work, such as the complexity of the work and the shield conductor becoming an obstacle during the terminal processing work, are solved.

The cable 1 according to the present invention can be widely used as a cable 1 having a power supply line 2 and a signal line 3, and can be widely used, for example, a general automobile electric brake cable or an automobile brake including an ABS sensor function. Can be used as a cable, etc.

(5) Modification of the embodiment:
It should be noted that the embodiments described above show one aspect of the present invention, and the present invention is not limited to the above-described embodiment, but includes the configuration of the present invention and can achieve the object and the effect. Needless to say, modifications and improvements within the scope are included in the content of the present invention. Further, the specific structure, shape, etc. in carrying out the present invention may be any other structure, shape, etc. within the range in which the object and effect of the present invention can be achieved. The present invention is not limited to the above-described embodiments, and modifications and improvements within the range in which the object of the present invention can be achieved are included in the present invention.

For example, in the above-described embodiment, a mode in which the shield layer 51 and the outermost layer 52 are formed one by one on the core portion 4 as the configuration of the cable 1 has been described with reference to FIG. The structure of the coating layer 5 is not limited, and for example, the shield layer 51 may be a plurality of layers, or a layer other than the shield layer 51 may be interposed between the core portion 4 and the shield layer 51. If 5 is composed of at least two layers (plurality of layers) and at least one layer of the coating layer 5 is the shield layer 51, the configuration can be arbitrarily determined.

Further, although the core portion 4 has been described by showing an embodiment of a multi-core stranded wire obtained by twisting two power supply lines 2 and two signal lines 3, the number of power supply lines 2 and signal lines 3 is a cable. It can be appropriately determined according to the characteristics required by 1. Further, a tape other than the shield conductor such as a non-woven fabric tape may be interposed around the core portion 4.
In addition, the specific structure, shape, etc. at the time of carrying out the present invention may be other structures, etc. as long as the object of the present invention can be achieved.

Hereinafter, the present invention will be described in more detail based on Examples and Comparative Examples, but the present invention is not limited thereto.

[Examples 1 to 6, Comparative Example 1 and Comparative Example 2]
Table 1 shows the shield layer (in Comparative Example 1 and Comparative Example 2, the layer corresponding to the shield layer. Hereinafter, including the corresponding layer, it may be referred to as “shield layer or the like” for convenience). A cable having the structure shown in FIG. 1 was manufactured using a resin composition having a constitution (a combination of a thermoplastic resin and a conductive filler. Comparative Example 1 is only a thermoplastic resin). In Table 1, the values (contents) of each component ((1) to (6)) of the shield layer and the like are (A) parts by mass of the conductive filler when (A) 100 parts by mass of the thermoplastic resin. , Is shown.

As shown in FIG. 1, in Examples 1 to 6, Comparative Example 1 and Comparative Example 2, the coating layer is covered with a shield layer or the like that covers the outer periphery of the core portion and the outer periphery of the shield layer or the like. The outermost layer is two layers, and only the resin composition constituting the shield layer and the like is different (the resin composition having the composition shown in Table 1), and the core portion consisting of the power supply line and the signal line and the outermost layer are common. did. In addition to each component of the thermoplastic resin such as the shield layer and the conductive filler whose composition is shown in Table 1, the materials and configurations of the core portion consisting of the power supply line and the signal line and the outermost layer are shown below.

(A) Thermoplastic resin:
(1) Ethylene-vinyl acetate copolymer (EVA):
Ethylene-vinyl acetate copolymer (vinyl acetate (VA) content 25% by mass) (trade name: Evaflex (registered trademark) EV360, manufactured by Mitsui-DuPont Polychemical Co., Ltd.)

(2) Ethylene-acrylic acid ester copolymer:
Ethylene-ethyl acrylate copolymer (EEA) (trade name: Lexpearl (registered trademark) A4200, manufactured by Japan Polyethylene Corporation)

(3) Ethylene-acrylic acid ester copolymer:
Ethylene-methyl acrylate copolymer (EMA) (trade name: Rotril (registered trademark) MA24005, manufactured by Arkema)

(B) Conductive filler:
(4) Carbon black:
Carbon black (trade name: RCF # 44, manufactured by Mitsubishi Chemical Corporation)

(5) Carbon nanotubes:
Carbon nanotube (trade name: VGCF-H, manufactured by Showa Denko KK)

(6) Metal nanoparticles:
Silver nanoparticles (trade name: Ag nano powder-2, manufactured by DOWA Electronics Co., Ltd.)

(Power line)
A tin (Sn) -containing alloy wire having a conductor composition of 7/72 / 0.08 is used as a conductor, flame-retardant cross-linked polyethylene is used as an insulating layer, and an outer diameter is φ2.9 mm (thickness of the insulating layer: 0.34 mm). The power line was obtained by extruding and coating so as to be.

(Signal line)
A tin (Sn) -containing alloy wire having a conductor composition of 3/16 / 0.08 is used as a conductor, flame-retardant cross-linked polyethylene is used as an insulating layer, and an outer diameter is φ1.4 mm (insulation layer thickness: 0.27 mm). A signal line was obtained by extruding and coating so as to be.

(Core part)
Two power lines and two signal lines obtained as described above were used to form a multi-core stranded wire twisted with a twist pitch length of 30 mm to obtain a core portion.

(Manufacturing method of outermost layer and cable)
As the outermost layer, flame-retardant crosslinked polyurethane, which is a polyurethane resin, was used. The cable is formed by first coating the outer periphery of the core portion obtained by extrusion molding with a general-purpose extrusion molding machine with the resin composition having the composition shown in Table 1 to form a shield layer or the like ( The thickness of the shield layer or the like: 0.375 mm), the shield layer or the like was coated, and then the flame-retardant crosslinked polyurethane was coated to form the outermost layer. The outer diameter after forming the shield layer or the like was 7.0 mm, and the outer diameter after forming the outermost layer was 7.7 mm (thickness of the outermost layer: 0.35 mm).

In Table 1, the volume resistivity (Ω · cm) of the shield layer (Examples 1 to 6) and the layer corresponding to the shield layer (Comparative Example 1 and Comparative Example 2) (resin composition constituting) is shown. ) Is also shown. The volume resistivity was measured according to the contents of "JIS C 2139 (Solid Electrical Insulation Material-Measuring Method of Volume resistivity and Surface resistivity)".

[Test Example 1]
With respect to the obtained Examples 1 to 6, Comparative Example 1 and Comparative Example 2, the shielding effect (dB) when the frequency of the electromagnetic wave noise was set to 20 MHz was confirmed, and the comparison and evaluation were performed. The results are shown in Table 1.

(Structure of shield layer, etc. and evaluation result)

As shown in Table 1, the cables shown in Examples 1 to 6 had a volume resistivity of 1 × 10 ¹⁴ Ω · cm or less in the shield layer, and also had a good shielding effect. On the other hand, in Comparative Example 1 and Comparative Example 2, the volume resistivity of the layer corresponding to the shield layer ^{exceeded 1 × 10 14} Ω · cm, and the shield layer of the present invention could not be obtained. Also, the shielding effect was inferior to that of the examples.

INDUSTRIAL APPLICABILITY The present invention can be used as a cable for an electric brake of an automobile or the like having a shielding effect, and has high industrial applicability.

1 …… Cable 2 …… Power line 21 …… Conductor 22 …… Insulation layer 3 …… Signal line 31 …… Conductor 32 …… Insulation layer 4 …… Core part 5 …… Coating layer 51 …… Shield layer 52 …… Outermost layer

In order to solve the above problems, the cable according to the present invention is a cable in which a coating layer is provided on the outer periphery of a core portion formed by twisting a plurality of power supply lines and a plurality of signal lines, and the coating layer is at least The thickness is composed of two layers, and at least one of the coating layers is a resin composition obtained by mixing a thermoplastic resin with at least one conductive filler from the group consisting of carbon black, carbon nanotubes, and metal nanoparticles. There is a shielding layer of 0.2 to 0.5 mm, and wherein the volume specific resistance before Symbol shielding layer is ³ × 10 3 Ω · cm to 1 × less ^{10 14 Ω} · cm.

Cable according to the present invention, in the present invention described above, the thermoplastic resin constituting at least one layer of the coating layer and wherein the polyurethane resin der Rukoto.

Claims (6)

In a cable in which a coating layer is provided on the outer circumference of a core portion formed by twisting a plurality of power supply lines and a plurality of signal lines.
The coating layer consists of at least two layers.
At least one of the coating layers is made of a resin composition obtained by mixing a thermoplastic resin with at least one conductive filler from the group consisting of carbon black, carbon nanotubes and metal nanoparticles, and having a thickness of 0.2 to 0. It is a 0.5 mm shield layer,
A cable characterized in that the volume resistivity of the shield layer is 3 × 10 ³ Ω · cm or more and 1 × 10 ¹⁴ Ω · cm or less. The cable according to claim 1, wherein the content of the conductive filler in the resin composition is 10 to 20 parts by mass with respect to 100 parts by mass of the thermoplastic resin. The cable according to claim 1 or 2, wherein the thermoplastic resin constituting at least one layer of the coating layer is a polyurethane resin. The cable according to any one of claims 1 to 3, wherein the coating layer (excluding the shield layer) is a flame-retardant crosslinked resin material. The cable according to any one of claims 1 to 4, wherein the coating layer contains a metal hydrate. The shielding effect (dB) when the frequency of electromagnetic noise is 20 MHz is 42 to 45 d.
The cable according to any one of claims 1 to 5, wherein the cable is B.

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