Multi-core cable

Abstract

The present invention provides a multi-core cable, which includes a plurality of covered electric wires and an outer coating covering the outer circumference of the plurality of covered electric wires, wherein the covered electric wires have a conductor and an insulating layer covering the conductor, and within a range of 0.1 mm from the outer surface of the outer coating and within a range of 0.1 mm from the inner surface of the outer coating, the storage modulus of the outer coating at -30°C is 300 MPa-400 MPa, both inclusive, and the outer coating is made of a polyolefin-based resin, a polyurethane elastomer, a polyester elastomer, or a composition obtained by mixing at least two of these materials.

Description

[0001] This application is a divisional application of the invention patent application filed on May 22, 2020, with the invention name “Multi-core Cable” and application number PCT / JP2020 / 020361 (domestic application number: 2020800055239). Technical Field

[0002] The present disclosure relates to multi-core cables.

[0003] This application is based upon and claims the benefit of priority of International Application No. PCT / JP2019 / 021154 filed on May 28, 2019, the entire contents of which are incorporated herein by reference. Background Art

[0004] Patent Document 1 discloses a multi-core cable for a vehicle, the multi-core cable including two covered electric wires and a sheath covering the two covered electric wires.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] [Patent Document 1] Japanese Patent Publication No. 2018-32515 Summary of the invention

[0008] According to one aspect of the disclosure of the present invention, a multi-core cable comprises:

[0009] A plurality of covered electrical wires; and

[0010] an outer coating covering the outer periphery of the plurality of covered electric wires,

[0011] Each of the plurality of covered electric wires comprises a conductor and an insulating layer covering the conductor.

[0012] The storage modulus of the outer film at -30°C is 300 MPa or more and 400 MPa or less within a range of 0.1 mm from the outer surface of the outer film and within a range of 0.1 mm from the inner surface of the outer film, and

[0013] The outer coating film is made of a polyolefin-based resin, a polyurethane elastomer, a polyester elastomer, or a composition obtained by mixing at least two of these materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a cross-sectional view perpendicular to the longitudinal direction of a multi-core cable according to one aspect of the disclosure of the present invention;

[0015] Figure 2is another configuration example of a cross-sectional view perpendicular to the longitudinal direction of a multi-core cable according to one aspect of the disclosure of the present invention;

[0016] Figure 3 is another configuration example of a cross-sectional view perpendicular to the longitudinal direction of the multi-core cable according to one aspect of the disclosure of the present invention; and

[0017] Figure 4 It is a figure which shows schematically the testing method of the bending resistance in the experimental example. DETAILED DESCRIPTION

[0018] [Problems to be solved by the disclosure of the present invention]

[0019] The wheel is supported displaceably relative to the vehicle body, and the position of the wheel is displaced relative to the vehicle body, for example, when the vehicle is in use. Therefore, a multi-core cable connecting a control device mounted on the vehicle body and an electric parking brake, etc., provided around the wheel may be bent repeatedly. For this reason, from the viewpoint of improving the durability of the multi-core cable, high bending resistance is required.

[0020] An object of the present invention is to provide a multi-core cable having excellent bending resistance.

[0021] [Effects of the disclosure of the present invention]

[0022] According to the disclosure of the present invention, a multi-core cable having excellent bending resistance can be provided.

[0023] Embodiments will be described below.

[0024] [Description of Disclosed Embodiments of the Invention]

[0025] First, various aspects of the disclosure of the present invention are listed and described below. In the following description, the same reference numerals are assigned to the same or corresponding elements, and the same description thereof will not be repeated.

[0026] (1) According to one aspect of the disclosure of the present invention, a multi-core cable comprises:

[0027] A plurality of covered electrical wires; and

[0028] An outer coating covering the outer periphery of the plurality of coated electric wires,

[0029] Each of the plurality of covered electric wires includes a conductor and an insulating layer covering the conductor, and

[0030] However, the storage elastic modulus of the outer coating film at -30°C within a range of 0.1 mm from the outer surface of the outer coating film is 300 MPa or more and 500 MPa or less.

[0031] By making the storage modulus of the outer coating at -30°C less than 600 MPa within a range of 0.1 mm from the outer surface of the outer coating, sufficient flexibility can be given to the outer surface side of the outer coating. In this way, by giving sufficient flexibility to the outer surface side of the outer coating, the outer surface side of the outer coating of the multi-core cable can be deformed even when a force is applied to the multi-core cable. Therefore, when a force is applied to the multi-core cable, the outer coating does not hinder the deformation inside the multi-core cable. Therefore, it can be considered that the disconnection of the coated electric wires such as the power cord inside the multi-core cable can be suppressed, and the bending resistance can be improved.

[0032] In particular, in an environment below freezing, although the storage modulus of the outer coating decreases and the multi-core cable is not easily deformed by a force applied from the outside, even in such an environment, it is necessary to improve the bending resistance. Therefore, as described above, it is preferred that the storage modulus of the outer coating in this area at -30°C satisfies the above range.

[0033] It should be noted that the outer coating also has the function of protecting the covered electric wire from flying objects such as flying stones and preventing the covered electric wire from being damaged. Therefore, for example, in the case where flying stones or the like collide with the outer periphery of the multi-core cable, from the viewpoint of protecting the covered electric wire such as the internal power line, it is preferred that the storage modulus of the outer coating at -30°C is 100 MPa or more within a range of 0.1 mm from the outer surface of the outer coating.

[0034] Therefore, by setting the storage elastic modulus of the outer coating film at -30°C to 300 MPa or more and 500 MPa or less within a range of 0.1 mm from the outer surface of the outer coating film, the bending resistance can be further improved while sufficiently protecting the covered electric wire from flying objects such as flying stones.

[0035] (2) The storage modulus of the outer coating film at -30°C within a range of 0.1 mm from the outer surface of the outer coating film may be 300 MPa or more and 400 MPa or less.

[0036] (3) The storage modulus of the resin material of the outer coating at -30°C within a range of 0.1 mm from the inner surface of the outer coating facing the plurality of covered electric wires may be smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0037] (4) The outer coating may include a first coating layer and a second coating layer in order from the plurality of covered electric wires side, and

[0038] The storage modulus of the second coating layer at -30°C may be 300 MPa or more and 500 MPa or less.

[0039] (5) The storage modulus of the second coating layer at -30°C may be 300 MPa or more and 400 MPa or less.

[0040] (6) The storage modulus of the first coating at -30°C may be smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0041] (7) The outer coating may include a first coating layer and a second coating layer in order from the plurality of covered electric wires side, and

[0042] The storage modulus of the first coating layer at -30°C may be 100 MPa or more and 500 MPa or less, and

[0043] The storage modulus of the second coating layer at -30°C may be 100 MPa or more and 600 MPa or less, and the storage modulus of the first coating layer at -30°C may be smaller than the storage modulus of the outer surface of the overcoat film at -30°C.

[0044] (8) The outer coating may include a first coating layer and a second coating layer in order from the plurality of covered electric wires side, and

[0045] The storage modulus of the first coating layer at -30°C may be 100 MPa or more and 400 MPa or less, and

[0046] The storage modulus of the second coating layer at -30°C may be 300 MPa or more and 500 MPa or less, and the storage modulus of the first coating layer at -30°C may be smaller than the storage modulus of the outer surface of the outer coating film at -30°C.

[0047] (9) The outer coating may include a first coating layer and a second coating layer in order from the plurality of covered electric wires side, and

[0048] The storage modulus of the first coating layer at -30°C may be 100 MPa or more and 300 MPa or less, and

[0049] The storage modulus of the second coating layer at -30°C may be 300 MPa or more and 400 MPa or less, and the storage modulus of the first coating layer at -30°C may be smaller than the storage modulus of the outer surface of the overcoat film at -30°C.

[0050] (10) The second coating layer may contain a polyurethane resin including one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide and talc.

[0051] (11) According to one aspect of the disclosure of the present invention, a multi-core cable comprises:

[0052] a plurality of coated wires including power wires and twisted pair signal wires; and

[0053] An outer coating covering the outer periphery of the plurality of coated electric wires,

[0054] The power cord includes a plurality of conductors twisted together and an insulating layer covering the plurality of conductors.

[0055] Among them, the twisted pair signal line includes two signal lines twisted together.

[0056] The outer coating includes a first coating layer and a second coating layer in order from the side of the plurality of covered electric wires.

[0057] wherein the second coating layer is composed only of a polyurethane resin, the polyurethane resin includes one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide and talc, and the storage modulus of the second coating layer at -30°C is 300 MPa or more and 500 MPa or less, and

[0058] The storage modulus of the first coating at -30°C is smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0059] [Details of the disclosed embodiment of the present invention]

[0060] A specific example of a multi-core cable according to an embodiment of the disclosure of the present invention (hereinafter referred to as "this embodiment") will be described below with reference to the accompanying drawings. It should be noted that the present invention is not limited to these examples, but is proposed in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0061] First, refer to Figures 1 to 3 The configuration of the multi-core cable according to the present embodiment will be described.

[0062] Figure 1 A cross-sectional view in a plane perpendicular to the longitudinal direction of the multi-core cable 10 according to the present embodiment is shown.

[0063] like Figure 1 As shown, the multi-core cable 10 according to this embodiment may include a plurality of covered electric wires. Each covered electric wire includes a conductor and an insulating layer covering the conductor. Figure 1 A case including two power supply lines 11 and the twisted pair signal wires 12 including two signal wires 121 is shown as the plurality of covered electric wires, but the configuration of the plurality of covered electric wires included in the multi-core cable according to the present embodiment is not limited to this configuration.

[0064] The multi-core cable 10 of this embodiment may further include an outer coating 14 covering the outer peripheries of the plurality of coated wires. The outer coating 14 may have a storage modulus of 100 MPa to 600 MPa at -30°C within a range of 0.1 mm from an outer surface 14A of the outer coating 14 .

[0065] The plurality of covered electric wires included in the multi-core cable according to the present embodiment are not limited to the above Figure 1The configuration example shown. Depending on the device etc. connected to the multi-core cable, a desired number of covered electric wires having a desired configuration may be included. Other configuration examples of the plurality of covered electric wires included in the multi-core cable according to the present embodiment will be described below.

[0066] Figure 2 A cross-sectional view in a plane perpendicular to the longitudinal direction of a multi-core cable 20 according to another configuration example of the present embodiment is shown, and Figure 3 A cross-sectional view in a plane perpendicular to the longitudinal direction of a multi-core cable 30 according to another configuration example of the present embodiment is shown.

[0067] For example, Figure 2 The multi-core cable 20 shown includes a single wire 21 in addition to two power lines 11 and a twisted pair signal line 12 including two signal lines 121. Also, for example, Figure 3 The illustrated multi-core cable 30 includes two power lines 11 and two twisted pair signal lines 12, each of which includes two signal lines 121. In this manner, the multi-core cable can include a desired number of coated wires having a desired configuration.

[0068] Hereinafter, each component of the multi-core cable according to the present embodiment will be described.

[0069] (1) Covered wire

[0070] As described above, the multi-core cable of the present embodiment may include a plurality of coated wires. The configuration of the plurality of coated wires is not particularly limited, and the configuration may be selected as desired depending on the device to be connected or the voltage to be applied. The multi-core cable according to the present embodiment may include, for example, one or more selected from a power line, a signal line, an electric line, etc. as the coated wire.

[0071] Configuration examples of a power supply line, a signal line, and an electric line as the covered electric line will be described below.

[0072] (1-1) Power cord

[0073] The power line 11 may include a first conductor 111 and a first insulating layer 112 covering the first conductor 111. It should be noted that Figures 1 to 3 Each of the illustrated multi-core cables 10 , 20 , and 30 includes two power lines 11 , and the two power lines may have the same size and material.

[0074] The two power lines 11 can be used to connect, for example, an electric parking brake (EPB) and an electronic control unit (ECU). The EPB includes an electric motor that drives a brake caliper. For example, one of the power lines 11 can be used as a power line for supplying power to the motor, and the other of the power lines 11 can be used as a ground line for the motor.

[0075] The first conductor 111 may be formed by twisting a plurality of conductors together. A wire made of copper or a copper alloy may be used for the conductor. In addition to copper and copper alloys, the conductor may be made of a material having a predetermined degree of conductivity and softness, such as tinned soft copper wire and soft copper wire. The conductor may be made of hard copper wire. The cross-sectional area of ​​the first conductor 111 may be 1.4 mm 2 Above and 3mm 2 It should be noted that the power line 11 may also include a plurality of first conductors 111 .

[0076] The first insulating layer 112 may be made of a composition having a synthetic resin as a main component, and is laminated on the outer periphery of the first conductor 111 to cover the first conductor 111. The average thickness of the first insulating layer 112 is not particularly limited, but may be, for example, 0.1 mm or more and 5 mm or less. Here, the "average thickness" refers to the average value of the thickness measured at any ten points. It should be noted that, hereinafter, the "average thickness" is also defined similarly for other members, etc.

[0077] The main component of the first insulating layer 112 is not particularly limited as long as it has insulating properties, and from the viewpoint of improving flexibility at low temperatures, a copolymer of ethylene and an α-olefin having a carbonyl group (hereinafter also referred to as a main component resin) is preferred. The lower limit of the content of the α-olefin having a carbonyl group in the above-mentioned main component resin is preferably 14% by mass, and more preferably 15% by mass. On the other hand, the upper limit of the content of the α-olefin having a carbonyl group is preferably 46% by mass, and more preferably 30% by mass. Preferably, the content of the α-olefin having a carbonyl group is greater than or equal to the above lower limit, because this can particularly improve the bending resistance at low temperatures. In addition, it is preferred that the content of the α-olefin having a carbonyl group is less than or equal to the above upper limit, because this can improve mechanical properties, such as improving the strength of the first insulating layer 112.

[0078] As the α-olefin having a carbonyl group, it is preferred to select one or more of the following: (meth) alkyl esters such as methyl (meth) acrylate and ethyl (meth) acrylate; (meth) aryl esters such as phenyl (meth) acrylate; vinyl esters such as vinyl acetate and vinyl propionate; unsaturated acids such as (meth) acrylic acid, crotonic acid, maleic acid, itaconic acid; vinyl ketones such as methyl vinyl ketone and phenyl vinyl ketone; (meth) acrylamide; etc. Among them, more preferred are one or more selected from (meth) alkyl esters and vinyl esters, and further preferred are one or more selected from ethyl acrylate and vinyl acetate.

[0079] Examples of the above-mentioned main component resin include resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA) and ethylene-butyl acrylate copolymer (EBA). Among them, one or more selected from EVA and EEA are preferred.

[0080] The first insulating layer 112 may include additives such as flame retardants, flame retardant aids, antioxidants, lubricants, colorants, reflection imparting agents, concealing agents, processing stabilizers, plasticizers, etc. The first insulating layer 112 may also include other resins in addition to the above main component resins.

[0081] The upper limit of the content of other resins is preferably 50 mass percent, more preferably 30 mass percent, and further more preferably 10 mass percent. The first insulating layer 112 may also be substantially free of other resins.

[0082] Examples of flame retardants include halogen-based flame retardants such as brominated flame retardants and chlorine-based flame retardants, non-halogen-based flame retardants such as metal hydroxides, nitrogen-based flame retardants, and phosphorus-based flame retardants, etc. One flame retardant may be used alone, or two or more flame retardants may be used in combination.

[0083] Examples of brominated flame retardants include decabromodiphenylethane and the like. Examples of chlorine-based flame retardants include chlorinated paraffin, chlorinated polyethylene, chlorinated polyphenols, perchloropentacyclodecane and the like. Examples of metal hydroxides include magnesium hydroxide, aluminum hydroxide and the like. Examples of nitrogen-based flame retardants include melamine cyanurate, triazine, isocyanurate, urea, guanidine and the like. Examples of phosphorus-based flame retardants include phosphinate metal salts, phosphaphenanthrene, melamine phosphate, ammonium phosphate, phosphate esters, polyphosphazenes and the like.

[0084] As the flame retardant, from the viewpoint of reducing environmental load, a non-halogen-based flame retardant is preferred, and a metal hydroxide, a nitrogen-based flame retardant, a phosphorus-based flame retardant is more preferred.

[0085] In the case where the first insulating layer 112 includes a flame retardant, the lower limit of the flame retardant content in the first insulating layer 112 is preferably 10 parts by mass, and more preferably 50 parts by mass, relative to 100 parts by mass of the resin component. On the other hand, the upper limit of the flame retardant content is preferably 200 parts by mass, and more preferably 130 parts by mass, relative to 100 parts by mass of the resin component. In the case where the content of the flame retardant is lower than the above lower limit, the flame retardant effect may not be fully imparted. On the contrary, when the content of the flame retardant exceeds the above upper limit, the extrusion moldability of the first insulating layer 112 may be impaired, and mechanical properties such as elongation and tensile strength may be impaired.

[0086] In the first insulating layer 112, the resin component is preferably cross-linked. Examples of a method of cross-linking the resin component of the first insulating layer 112 include a method of irradiating with ionizing radiation, a method of using a thermal cross-linking agent, and a method of using a silane graft polymer, and a method of irradiating with ionizing radiation is preferred. Also, in order to promote cross-linking, it is also preferred that a silane coupling agent is added to the composition forming the first insulating layer 112.

[0087] (1-2) Signal line

[0088] The signal line 121 includes a second conductor 1211 thinner than the first conductor 111 and a second insulating layer 1212 covering the second conductor 1211. The signal line 121 can be twisted together in the form of a pair of two wires to form a twisted pair signal line 12. The two signal lines 121 twisted together in the longitudinal direction can have the same size and material. The twist pitch of the twisted pair signal line 12 is not particularly limited, but for example, it can be more than four times and less than ten times the twist diameter of the twisted pair signal line 12 (the outer diameter of the twisted pair signal line 12).

[0089] In the case where the multi-core cable includes the power line 11 and the twisted pair signal lines 12 , the outer diameter of the twisted pair signal lines 12 may be substantially the same as the outer diameter of the power line 11 .

[0090] The signal line 121 can also be used to transmit signals from sensors, and can also be used to transmit control signals from the ECU. The two signal lines 121 can be used, for example, for wiring of an anti-lock braking system (ABS). For example, the corresponding two signal lines 121 can be used, for example, to connect a differential wheel speed sensor to the ECU of a vehicle. The two signal lines 121 can also be used to transmit other signals.

[0091] The second conductor 1211 may be composed of a single conductor, or may be composed by twisting a plurality of conductors together similarly to the power cord 11. The second conductor 1211 may be made of the same material as the conductor constituting the first conductor 111 described above, or may be made by using a different material. The cross-sectional area of ​​the second conductor 1211 is not particularly limited, but may be, for example, 0.13 mm 2 Above and 0.5mm 2 It should be noted that the signal line 121 may also include a plurality of second conductors 1211 .

[0092] The material of the second insulating layer 1212 is not particularly limited, but may be made of, for example, a flame-retardant polyolefin-based resin such as cross-linked polyethylene having flame retardancy by mixing a flame retardant. The material of the second insulating layer 1212 is not limited to the flame-retardant polyolefin-based resin, and may be made of another material such as a cross-linked fluorine-based resin. The outer diameter of the second insulating layer 1212 may be, for example, 1.0 mm or more and 2.2 mm or less.

[0093] (1-3) Wires

[0094] like Figure 2 As shown in the multi-core cable 20 , the multi-core cable according to this embodiment may further include an electric wire 21 as a covered electric wire.

[0095] The electric wire 21 includes a third conductor 211 thinner than the first conductor 111 and a third insulating layer 212 covering the third conductor 211. The electric wire 21 may have the same size and material as the signal line 121.

[0096] The wires 21 may be used to transmit signals from sensors, or may be used to transmit control signals from an ECU, or they may be used as power feeders to provide power to electronic devices. The wires 21 may also be used as ground wires.

[0097] The third conductor 211 may be composed of a single conductor, or may be composed by twisting a plurality of conductors together similarly to the power cord 11. The third conductor 211 may be composed of the same material as the conductor constituting the first conductor 111 or the second conductor 1211, or may be composed by using a different material. The cross-sectional area of ​​the third conductor 211 is not particularly limited, but may be, for example, 0.13 mm 2 Above and 0.5mm 2 It should be noted that the electric wire 21 may include a plurality of third conductors 211 .

[0098] The third insulating layer 212 may be made of the same material as the second insulating layer 1212, or may be made by using a different material. The outer diameter of the third insulating layer 212 may be 1.0 mm or more and 2.2 mm or less.

[0099] Two electric wires 21 are used, and they can be twisted together to form a twisted pair of electric wires. In this case, it is preferred that the two electric wires 21 twisted together have the same size and material. In the case where the electric wires are arranged in a multi-core cable as twisted pair electric wires together with twisted pair signal wires, it is preferred that the twisted pair electric wires and the twisted pair signal wires 12 are twisted in the same direction. Also, in this case, it is preferred that the twisted pair electric wires and the twisted pair signal wires 12 have the same twisting pitch. The outer diameter of the twisted pair electric wires can be approximately the same as the outer diameter of the twisted pair signal wires 12. The outer diameter of the twisted pair electric wires can be approximately the same as the outer diameter of the power cord 11.

[0100] As described above, the configuration of the plurality of covered electric wires included in the multi-core cable according to the present embodiment is not particularly limited. Depending on the device to which the multi-core cable is connected, etc., a desired number of covered electric wires having a desired configuration may be included. It should be noted that similar Figures 1 to 3 The multi-core cables 10, 20 and 30 shown preferably include a plurality of coated electric wires including a power line 11 and a twisted pair signal line 12. This is because the multi-core cable including the power line 11 and the twisted pair signal line 12 can be used for various purposes and can be a multi-core cable with high versatility.

[0101] The power line 11 and the twisted pair signal line 12 may have the above-described configurations, and for example, the power line may include a plurality of conductors twisted together and an insulating layer covering the plurality of conductors. Also, the twisted pair signal line 12 may include two signal lines twisted together.

[0102] It should be noted that although the power line, signal line, and electric line are described as examples of the covered electric wire, the first conductor 111, the second conductor 1211, and the third conductor 211 described above correspond to the conductors of the covered electric wire. Also, the first insulating layer 112, the second insulating layer 1212, and the third insulating layer 212 correspond to the insulating layers of the covered electric wire.

[0103] (2) External coating

[0104] As described above, the multi-core cable of the present embodiment may include a plurality of covered electric wires selected from the power line 11, the signal line 121, the electric wire 21, etc. Then, the plurality of covered electric wires may be twisted together in the longitudinal direction to form a core.

[0105] Specifically, for example, in Figure 1 In the case of the multi-core cable 10 shown, the core 13 can be constructed by twisting two power lines 11 and a single twisted pair signal line 12 together. Figure 2 In the case of the multi-core cable 20 shown, the core 23 can be constructed by twisting together two power lines 11, a single twisted pair signal line 12, and the electric wires 21. Figure 3 In the case of the multi-core cable 30 shown, the core 33 can be formed by twisting two power lines 11 and two twisted pair signal lines 12 together.

[0106] The total twisted diameter of the core obtained by twisting a plurality of covered electric wires together may be, for example, 5.5 mm or more and 9 mm or less.

[0107] In addition, the twisting pitch of the core obtained by twisting a plurality of coated electric wires together is not particularly limited, but for example, it can be more than 12 times and less than 24 times the twisting diameter of the core. By making the twisting pitch of the core less than 24 times the twisting diameter of the core, it is possible to prevent the twisting from becoming loose, and particularly enhance the bending resistance. In addition, by making the twisting pitch of the core more than 12 times the twisting diameter of the core, it is possible to particularly improve the productivity of the multi-core cable.

[0108] It should be noted that, in the case where the core includes a twisted pair signal line 12, the ratio of the twist pitch of the core to the twist diameter of the core is preferably greater than the ratio of the twist pitch of the twisted pair signal line 12 to the twist diameter of the twisted pair signal line 12. The twisting direction of the core is not particularly limited, but is preferably the same as the twisting direction of the twisted pair signal line 12.

[0109] The multi-core cable of the present embodiment may include an outer coating 14 covering the outer periphery of the plurality of coated electric wires as the core. At this time, the outer coating 14 may be arranged to completely cover the plurality of coated electric wires, ie, the core.

[0110] According to the inventors' research, the bending resistance of the multi-core cable can be particularly improved by setting the storage elastic modulus of outer coating 14 at -30°C to 100 MPa or more and 600 MPa or less within a range of 0.1 mm from outer surface 14A of outer coating 14 .

[0111] like Figures 1 to 3As shown, a region X is defined between the outer surface 14A of the outer coating 14 and the dashed line A at a distance L1 of 0.1 mm from the outer surface 14A. In a cross section perpendicular to the longitudinal direction of the multi-core cable, the outer surface 14A of the multi-core cable is generally circular in shape, and the dashed line A at a distance L1 of 0.1 mm from the outer surface 14A is similar to the shape of the outer surface 14A along the outer surface 14, and therefore the shape of the region X is circular. It should be noted that, with respect to the shape of the outer surface 14A of the multi-core cable in a cross section perpendicular to the longitudinal direction of the multi-core cable, "circle" refers not only to a circle in the strict sense (i.e., a true circle), but also includes circles other than a true circle such as an ellipse within an allowable tolerance of the multi-core cable.

[0112] Then, in this case, the storage modulus of the outer coating film 14 at -30°C in the region X is preferably 100 MPa or more and 600 MPa or less, more preferably 300 MPa or more and 500 MPa or less, and further more preferably 300 MPa or more and 400 MPa or less.

[0113] As described above, for example, a multi-core cable is used in a vehicle such as an automobile, and may be bent repeatedly when used in a vehicle or the like. For this reason, from the viewpoint of improving the durability of the multi-core cable, high bending resistance is required. It should be noted that a multi-core cable having high bending resistance refers to a multi-core cable that, in the case where the multi-core cable is bent repeatedly, requires repeated bending many times so that the resistance value increases due to cracking or disconnection of the coated electric wires contained in the multi-core cable.

[0114] Therefore, according to the careful study of the inventors of the present invention, by making the storage modulus of the outer film in the above-mentioned region X at -30°C less than 600 MPa, it is possible to give sufficient flexibility to the outer surface side of the outer film. In this way, by giving sufficient flexibility to the outer surface side of the outer film, even when a force is applied to the multi-core cable, the outer surface side of the outer film of the multi-core cable can be deformed. Therefore, when a force is applied to the multi-core cable, the deformation inside the multi-core cable is not hindered. Therefore, it can be considered that the disconnection of the coated electric wires such as the power cord inside the multi-core cable can be suppressed, and the bending resistance can be improved.

[0115] In particular, in an environment below freezing, the storage modulus of the outer coating decreases and the multi-core cable is not easily deformed by a force applied from the outside, but even in such an environment, it is necessary to improve the bending resistance. Therefore, as described above, it is preferred that the storage modulus of the outer coating at -30°C in region X satisfies the above range.

[0116] It should be noted that the outer coating also has the function of protecting the covered electric wire from flying objects such as flying stones and preventing the covered electric wire from being damaged. Therefore, for example, in the case where flying stones or the like collide with the outer periphery of the multi-core cable, from the viewpoint of protecting the covered electric wire such as the internal power line, it is preferred that the storage modulus of the outer coating at -30°C in the above-mentioned region X is 100 MPa or more.

[0117] By setting the storage elastic modulus of outer coating 14 at -30°C to 300 MPa or more and 500 MPa or less within a range of 0.1 mm from the outer surface of outer coating 14, the bending resistance can be further improved while sufficiently protecting the covered electric wire from flying objects such as flying stones.

[0118] Furthermore, by setting the storage elastic modulus of the outer coating 14 at -30°C to 300 MPa or more and 400 MPa or less within a range of 0.1 mm from the outer surface of the outer coating 14, the bending resistance can be particularly improved while sufficiently protecting the covered electric wire from flying objects such as flying stones.

[0119] It should be noted that, in the outer coating film 14 , not only the region X but also the entire outer coating film 14 may satisfy the preferred range of the storage modulus as described above.

[0120] It should be noted that in the multi-core cable of the present embodiment, it is preferred that, within a range of 0.1 mm from an inner surface 14B of the outer coating 14 facing the plurality of coated wires, the storage modulus of the resin material of the outer coating 14 at -30°C is lower than the storage modulus of the outer surface 14A of the outer coating 14 at -30°C.

[0121] like Figures 1 to 3 As shown, a region Y is defined between an inner surface 14B of the outer coating 14 disposed toward the plurality of coated electric wires and a dotted line B at a distance L2 of 0.1 mm from the inner surface 14B. In this case, it is preferred that, in the region Y, the storage modulus of the resin material of the outer coating 14 at -30°C is lower than the storage modulus of the outer surface 14A of the outer coating 14 at -30°C.

[0122] In the outer coating 14, by making the storage modulus of the resin material of the outer coating 14 at -30°C lower than the storage modulus of the outer surface 14A of the outer coating 14 at -30°C in the region Y provided toward the plurality of coated electric wires such as the power cord 11, the flexibility of the outer coating 14 in the region Y can be particularly increased. Therefore, even when the plurality of coated electric wires such as the power cord 11 are displaced or deformed, the region Y of the outer coating 14 can be utilized to absorb such displacement and the like in the region Y. Therefore, the disconnection of the plurality of coated electric wires can be particularly suppressed, and the bending resistance of the multi-core cable can be particularly improved.

[0123] The specific range of the storage modulus at -30°C of the resin material of the outer coating film 14 in the region Y is not particularly limited, but is, for example, preferably 500 MPa or less, more preferably 400 MPa or less, and further more preferably 300 MPa or less.

[0124] By setting the storage elastic modulus of the outer coating 14 in the region Y to 500 MPa or less at -30°C, sufficient flexibility can be imparted to the outer coating 14 in the region Y. Therefore, since the displacement or deformation of the plurality of coated electric wires generated when a force is applied to the multi-core cable is not hindered, the disconnection of the plurality of coated electric wires such as a power line inside the multi-core cable can be suppressed, and the bending resistance of the multi-core cable can be improved.

[0125] By making the storage modulus of the outer film 14 in the above-mentioned region Y at -30°C not more than 400 MPa, the disconnection of the coated wires such as the power cord inside the multi-core cable can be further suppressed, and the bending resistance can be further improved. By making the storage modulus of the outer film 14 in the above-mentioned region Y at -30°C not more than 300 MPa, the disconnection of the coated wires such as the power cord inside the multi-core cable can be particularly suppressed, and the bending resistance can be particularly improved.

[0126] In particular, in an environment below freezing, the storage modulus of the outer coating decreases and the multi-core cable is not easily deformed by a force applied from the outside, but even in such an environment, it is necessary to improve the bending resistance. Therefore, as described above, it is preferred that the storage modulus of the outer coating at -30°C in the region Y satisfies the above range.

[0127] It should be noted that, as described above, since the outer coating film 14 also has the function of protecting the plurality of covered electric wires, the storage modulus of the resin material of the outer coating film 14 in the region Y at -30°C is preferably 10 MPa or more, and more preferably 100 MPa or more.

[0128] The configuration of the outer coating film 14 is not particularly limited, and may be composed of a plurality of layers made of different materials to have a desired storage modulus. The outer coating film 14 may also be composed of one layer.

[0129] Specifically, for example, the outer coating film 14 may include a first coating layer 141 and a second coating layer 142 in order from the side of a plurality of coated electric wires such as the power supply wire 11 .

[0130] As described above, it is preferable that the outer cover film 14 is composed of a plurality of layers, because this makes it possible to easily adjust the storage modulus thereof depending on the position of the outer cover film 14 .

[0131] As described above, when the outer coating 14 includes the first coating layer 141 and the second coating layer 142, for example, the storage modulus of the second coating layer 142 at -30°C is preferably 100 MPa or more and 600 MPa or less, more preferably 300 MPa or more and 500 MPa or less, and further more preferably 300 MPa or more and 400 MPa or less.

[0132] This is because, by making the storage modulus of the second coating layer 142 within the above range, for example, the storage modulus of the outer coating film in the above region X can be easily made within a desired range. It should be noted that in this case, it is preferred that the second coating layer 142 includes, for example, the outer surface 14A of the outer coating film 14. That is, the second coating layer 142 is preferably arranged on the outermost peripheral side of the outer coating film 14.

[0133] In addition, the thickness of the second coating layer 142 is not particularly limited, but is preferably 0.1 mm or more, and more preferably 0.3 mm or more, for example. It should be noted that although the upper limit of the thickness of the second coating layer 142 is not particularly limited, it is preferably 1.0 mm or less, and more preferably 0.8 mm or less.

[0134] Also, as described above, when the outer coating 14 includes the first coating 141 and the second coating 142 , for example, the storage modulus of the first coating 141 at −30° C. is preferably lower than the storage modulus of the outer surface 14A of the outer coating 14 at −30° C.

[0135] This is because, by making the storage modulus of the first coating layer 141 within the above range, for example, the storage modulus of the outer coating film in the above region Y can be easily made within a desired range. It should be noted that in this case, it is preferable that the first coating layer 141 includes, for example, the inner surface 14B of the outer coating film 14. That is, it is preferable that the first coating layer 141 is arranged on the innermost peripheral side of the outer coating film 14, in other words, on the side of the plurality of coated electric wires.

[0136] In addition, the thickness of the first coating layer 141 is not particularly limited, but for example, the minimum value of the thickness (i.e., the thickness of the thinnest portion) is preferably 0.1 mm or more, and more preferably 0.3 mm or more. It should be noted that the upper limit of the thickness of the thinnest portion of the first coating layer 141 is not particularly limited, but is preferably 1.0 mm or less, and more preferably 0.8 mm or less.

[0137] The specific range of the storage modulus of the first coating layer 141 at -30°C is not particularly limited, but is, for example, preferably 500 MPa or less, more preferably 400 MPa or less, and further more preferably 300 MPa or less. The lower limit value of the storage modulus of the first coating layer 141 at -30°C is not particularly limited, but is, for example, preferably 10 MPa or more, and more preferably 100 MPa or more.

[0138] This is because, by making the storage modulus of the first coating layer 141 within the above range, for example, the storage modulus of the outer coating film in the above region Y can be easily made within a desired range. In this case, it is preferred that the first coating layer 141 includes, for example, the inner surface 14B of the outer coating film 14. That is, it is preferred that the first coating layer 141 is arranged on the innermost peripheral side of the outer coating film 14, in other words, on the side of the plurality of coated electric wires.

[0139] The material of the outer film 14 is not particularly limited but may be made of a polyolefin-based resin such as polyethylene or ethylene-vinyl acetate copolymer (EVA), a polyurethane elastomer (polyurethane resin), a polyester elastomer, or a composition obtained by mixing at least two of these materials.

[0140] For example, "Solumer 851T" (trade name, manufactured by SK Global Chemical Co., Ltd.) is commercially available as polyethylene, and, for example, "Evaflex EV360" (trade name, manufactured by DuPont-Mitsui Polychemicals Co., Ltd.) is commercially available as EVA, and they can be appropriately selected from various grades of commercially available products for use.

[0141] Also, for example, cross-linked / non-cross-linked thermoplastic polyurethane (TPU) excellent in wear resistance can be used as the material of the outer coating film 14. Since the heat resistance is excellent, the cross-linked thermoplastic polyurethane can be preferably used as the material of the outer coating film 14. As the thermoplastic polyurethane, for example, "Elastollan ET385" (trade name, produced by BASF) and "Miractran E385PNAT-N" (trade name, produced by Tosoh Corporation) are commercially available, and can be appropriately selected from various grades of commercially available products for use.

[0142] The specific method for making the storage modulus of the outer coating 14 at -30°C within the desired range is not particularly limited. For example, by selecting the material, density, etc. of the outer coating 14, the desired storage modulus can be achieved. For example, the storage modulus thereof can also be adjusted by mixing an inorganic material such as a flame retardant into the resin material of the outer coating 14. In the case of mixing an inorganic substance such as a flame retardant with the resin material of the outer coating 14, the mixing ratio is not particularly limited. For example, an inorganic substance such as a flame retardant is preferably added in an amount of 12 parts by mass or less, and more preferably added in an amount of 10 parts by mass or less, relative to 100 parts by mass of the resin material.

[0143] Since there is a possibility that the storage modulus increases when the addition amount is excessive relative to 100 parts by mass of the inorganic material, the addition amount is preferably 12 parts by mass or less.

[0144] Examples of the inorganic material to be added may include one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc.

[0145] The outer coating film 14 may include the first coating layer 141 and the second coating layer 142 as described above. In this case, the first coating layer 141 and the second coating layer 142 may be made of different materials, or may be made of the same material. Also, for example, in the first coating layer 141 and the second coating layer 142, by changing the amount of an additive of an inorganic material such as a flame retardant, the storage modulus of each layer may be adjusted.

[0146] The materials of the first coating layer 141 and the second coating layer 142 are not particularly limited, and for example, the materials described with respect to the overcoat film 14 may be used.

[0147] As the material of the first coating layer 141, one or more selected from polyurethane resin and polyethylene resin may be preferably used. In order to adjust the storage modulus as described above, the first coating layer 141 may further contain an inorganic material such as a flame retardant as needed.

[0148] As the material of the second coating layer 142, polyurethane resin having excellent wear resistance can be preferably used. Since the second coating layer 142 is arranged outside the multi-core cable, the durability of the multi-core cable can be particularly improved by using polyurethane resin as the material of the second coating layer 142.

[0149] In order to adjust the storage modulus as described above, the second coating layer 142 may also further contain an inorganic material such as a flame retardant. Therefore, for example, the second coating layer 142 preferably contains a polyurethane resin containing one or more of antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc. The second coating layer 142 may also be composed only of a polyurethane resin including one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc.

[0150] By constituting the second coating layer 142 with the above-mentioned material, the durability of the multi-core cable can be particularly improved, and the storage modulus of the second coating layer 142 can be easily adjusted.

[0151] The multi-core cable of this embodiment may further include components other than the plurality of covered electric wires and the outer coating as required.

[0152] For example, the suppression roll 15 may be provided to cover the outer periphery of the plurality of coated electric wires. The suppression roll 15 covers the core portion obtained by twisting the plurality of coated electric wires together. By arranging the suppression roll 15, the shape obtained by twisting the plurality of coated electric wires constituting the core portion together can be stably maintained. The suppression roll 15 may be provided on the inner side of the outer coating film 14.

[0153] For example, a paper tape, a nonwoven fabric, a tape made of a resin such as polyester, etc. can be used as the suppression roll 15. The suppression roll 15 can also be spirally wound along the longitudinal direction of the core, or can be constructed in a longitudinal manner so that the longitudinal direction of the suppression paper is arranged along the longitudinal direction of the core. Also, the winding direction can be Z-winding or S-winding. In the case where the core 13 includes a twisted pair signal line 12, etc., the winding direction of the suppression roll 15 can be the same as the twisting direction of the twisted pair signal line 12, etc. included in the core 13, or can be wound in the opposite direction. However, the winding direction of the suppression roll 15 is preferably opposite to the twisting direction of the twisted pair signal line 12, etc., because protrusions / depressions are not likely to appear on the surface of the suppression roll 15, and it is easy to stabilize the outer diameter shape of the multi-core cable.

[0154] It should be noted that since the suppression roll 15 has a cushioning function to increase flexibility and a protection function from external influences, one or more layers of the outer coating 14 can be made thinner when the suppression roll 15 is provided. By providing the suppression roll 15 in this way, a multi-core cable that is more flexible and excellent in wear resistance can be provided.

[0155] Also, in the case where the outer coating film 14 made of resin is provided by extrusion coating, the resin may enter between the plurality of coated wires, making it difficult to separate the plurality of coated wires at the end of the multi-core cable. Therefore, by providing the suppression roll 15, the resin can be prevented from entering between the plurality of coated wires, and the plurality of coated wires such as power lines can be easily led out at the end.

[0156] Also, the multi-core cable of this embodiment may have an insert in the region 16 between the outer coating 14 and the core, for example. The insert may be made of fibers such as rayon and nylon yarn. The insert may be made of tensile strength fibers.

[0157] The insertion portion may be arranged in a gap formed between the covered electric wires, such as between the power lines 11 or between the power line 11 and the signal line 121 .

[0158] Although the embodiments have been described in detail above, it should be understood that various changes and modifications may be made within the scope of the appended claims and are not limited to the specific embodiments.

[0159] Examples

[0160] Although specific examples will be described below, the present invention is not limited to these examples.

[0161] (Evaluation method)

[0162] First, a method of evaluating the multi-core cables prepared in the following experimental examples will be described.

[0163] (1) Evaluation of storage modulus of outer film

[0164] In each of the following experimental examples, the same resin (composition) as the resin (composition) used to form the outer coating film 14 was melt-extruded to prepare a sample for measuring the storage modulus. It should be noted that for each of Experimental Examples 1 and Experimental Examples 3 to 7, an outer coating film 14 including a first coating layer 141 and a second coating layer 142 was formed. Therefore, using the same resin as the resin used to form each coating layer, two samples for measuring the storage modulus were prepared.

[0165] For each prepared sample, the storage modulus was measured in the range of -50°C to 200°C under the conditions of a strain of 0.08%, a frequency of 10 Hz, and a heating rate of 10°C / min in accordance with JIS-K7244-1 (1998) using a dynamic viscoelasticity analyzer ("DVA200" manufactured by IT Keisokusseigyo KK).

[0166] In each of Experimental Examples 1 and 3 to 7, the storage modulus at -30°C of the same resin as the resin used to form the first coating layer 141 obtained by such measurement is the storage modulus at -30°C of the first coating layer 141. In addition, the storage modulus at -30°C of the same resin as the resin used to form the second coating layer 142 obtained by such measurement is the storage modulus at -30°C of the second coating layer 142.

[0167] In Experimental Example 2, the storage modulus at -30°C of the same resin as the resin used to form the outer coating film 14 obtained by such measurement is the storage modulus of the outer coating film 14 at -30°C.

[0168] (2) Bending resistance test

[0169] For the multi-core cables obtained in the following experimental examples, a bending resistance test was performed in accordance with JIS C6851 (2006) (Optical Fiber Test Procedure).

[0170] Specifically, Figure 4 As shown, a multi-core cable 42 to be evaluated is inserted in a vertical direction between two mandrels 411 and 412 with a diameter of 60 mm arranged horizontally and in parallel. The following actions are repeated in a constant temperature bath at -30°C: the upper end is bent 90° to the horizontal direction to contact the upper side of one mandrel 411, and then it is bent 90° to the horizontal direction to contact the upper side of the other mandrel 412. This repetitive action is performed while measuring the resistance value with the two conductors in the cable connected, and the number of times the resistance increases to more than ten times the initial resistance value (the number of bends to the right, to the left, and then back to the right is defined as one time) is defined as the index value of the bending resistance test. It should be noted that as the index value of the bending resistance test increases, that is, as the number of bends increases, it means that the bending resistance is excellent.

[0171] (Experimental example)

[0172] Hereinafter, experimental conditions will be described. Experimental Examples 1, 3 to 7 are examples, and Experimental Example 2 is a comparative example.

[0173] [Experimental Example 1]

[0174] preparation Figure 1 The multi-core cable 10 shown in the figure was evaluated. Specifically, the core 13 includes two power lines 11 and a twisted pair signal line 12 including two signal lines 121 .

[0175] Each power line 11 includes seven first conductors 111. Each first conductor 111 is formed by twisting forty-eight conductors together, and the outer diameter of the first conductor 111 is 2.7 mm, and the cross-sectional area of ​​the first conductor 111 is 1.7 mm. 2 .

[0176] The twisted pair signal line 12 is formed by twisting together signal lines 121 each including three second conductors 1211. Each second conductor 1211 is formed by twisting together sixteen conductors, the outer diameter of the second conductor 1211 is 1.6 mm, and the cross-sectional area of ​​the second conductor 1211 is 0.25 mm. 2 .

[0177] The core 13 is formed by twisting together two power supply lines 11 and a twisted pair signal line 12 in the longitudinal direction. Then, around the core, a thin paper is arranged as a restraining roll 15, and an outer coating film 14 is arranged to cover the core 13.

[0178] The outer coating 14 includes a first coating layer 141 and a second coating layer 142. The first coating layer 141 has a minimum thickness of 0.65 mm and is made of polyethylene resin. The second coating layer 142 has a thickness of 0.5 mm and is formed of a material in which antimony trioxide as an inorganic material is added to a polyurethane resin at a ratio of 12 parts by mass to 100 parts by mass of the polyurethane resin.

[0179] When the storage modulus of the polyethylene resin used to form the first coating layer 141 was measured at -30°C, it was 200 MPa (indicated as "storage modulus of the first coating layer" in Table 1). Figure 1 In region Y, the storage modulus of the outer coating film 14 at -30°C is 200 MPa. It should be noted that for each of the following Experimental Examples 3 to 7, the storage modulus of the material used to form the first coating layer at -30°C is Figure 1 The storage modulus of the outer coating film 14 in the region Y at -30°C.

[0180] Also, when the storage modulus of the material for forming the second coating layer 142 was measured at -30°C, it was 400 MPa (indicated as "storage modulus of the second coating layer" in Table 1), wherein antimony trioxide as an inorganic material was added to the polyurethane resin at a ratio of 12 parts by mass to 100 parts by mass of the polyurethane resin. Figure 1 In the region X and the outer surface 14A, the storage modulus of the outer coating 14 at -30°C is 400 MPa. It should be noted that for each of Experimental Examples 3 to 7, the storage modulus of the material used to form the second coating at -30°C is Figure 1 The storage modulus of the outer film 14 and the outer surface 14A in the region X at -30°C.

[0181] The evaluation results are shown in Table 1.

[0182] [Experimental Example 2]

[0183] A multi-core cable was prepared similarly to the case of Experimental Example 1 except that the outer coating 14 was made of a material in which antimony trioxide as an inorganic material was added to a polyurethane resin at a ratio of 15 parts by mass to 100 parts by mass of the polyurethane resin as a single layer.

[0184] When the storage modulus at -30°C of the material for forming the outer coating film 14 in which antimony trioxide as an inorganic material was added to the polyurethane resin at a ratio of 15 parts by mass to 100 parts by mass of the polyurethane resin was measured, it was 650 MPa.

[0185] therefore, Figure 1 The storage modulus of the outer coating film 14 at -30°C is 650 MPa at any position of the outer coating film 14.

[0186] [Experimental Example 3]

[0187] In the outer coating film 14, the first coating layer 141 is made of a polyethylene resin having a density different from that of the first coating layer 141 of Experimental Example 1. Also, the second coating layer 142 is made of a polyurethane resin.

[0188] A multi-core cable was prepared similarly to Experimental Example 1 except for the above-mentioned differences.

[0189] [Experimental Example 4]

[0190] In the outer coating film 14 , the first coating layer 141 is made of a polyethylene resin having a density different from that of the first coating layer 141 in each of Experimental Examples 1 and 3. Also, the second coating layer 142 is made of a polyurethane resin.

[0191] A multi-core cable was prepared similarly to Experimental Example 1 except for the above-mentioned differences.

[0192] [Experimental Example 5]

[0193] In the outer coating film 14, the first coating layer 141 is made of a polyethylene resin having a density different from that of the first coating layer 141 in each of Experimental Examples 1, 3, and 4. Also, the second coating layer 142 is made of a material obtained by adding 5 parts by mass of talc as an inorganic material to 100 parts by mass of a polyurethane resin.

[0194] A multi-core cable was prepared similarly to Experimental Example 1 except for the above-mentioned differences.

[0195] [Experimental Example 6]

[0196] In the outer coating film 14, the first coating layer 141 is made of a polyethylene resin having a density different from that of the first coating layer 141 in each of Experimental Examples 1 and 3 to 5. Also, the second coating layer 142 is made of a material obtained by adding 10 parts by mass of talc as an inorganic material to 100 parts by mass of a polyurethane resin.

[0197] A multi-core cable was prepared similarly to Experimental Example 1 except for the above-mentioned differences.

[0198] [Experimental Example 7]

[0199] In the outer coating film 14, the first coating layer 141 is made of a polyethylene resin having a density different from that of the first coating layer 141 in each of Experimental Examples 1 and Experimental Examples 3 to 6. Also, the second coating layer 142 is made of a material obtained by adding 12 parts by mass of talc as an inorganic material to 100 parts by mass of a polyurethane resin.

[0200] A multi-core cable was prepared similarly to Experimental Example 1 except for the above-mentioned differences.

[0201] The evaluation results are shown in Table 1.

[0202] Table 1

[0203]

[0204]

[0205] According to the results shown in Table 1, it can be confirmed that the multi-core cables of Experimental Example 1 and Experimental Example 3 to Experimental Example 7, in which the storage modulus of the outer film 14 at -30°C within the range of 0.1 mm starting from the outer surface 14A of the outer film 14, that is, in the area X, is greater than 100 MPa and less than 600 MPa, are superior to the multi-core cable of Experimental Example 2 that does not meet the above requirements.

[0206] (Terms)

[0207] Furthermore, the disclosure of the present invention follows from the following aspects.

[0208] (Article 1)

[0209] A multi-core cable, comprising:

[0210] A plurality of covered electrical wires; and

[0211] an outer coating covering the outer periphery of the plurality of covered electric wires,

[0212] Each of the plurality of covered electric wires comprises a conductor and an insulating layer covering the conductor, and

[0213] The storage modulus of the outer coating film at -30°C within a range of 0.1 mm from the outer surface of the outer coating film is 100 MPa or more and 600 MPa or less.

[0214] (Article 2)

[0215] A multi-core cable according to claim 1, wherein, within a range of 0.1 mm from the inner surface of the outer coating facing the plurality of covered wires, the storage modulus of the resin material of the outer coating at -30°C may be smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0216] (Article 3)

[0217] A multi-core cable according to clause 1 or clause 2,

[0218] The outer coating includes a first coating layer and a second coating layer in order from the side of the plurality of covered wires, and

[0219] Wherein, the storage modulus of the second coating at -30°C is greater than 100 MPa and less than 600 MPa.

[0220] (Article 4)

[0221] The multi-core cable according to clause 3, wherein the storage modulus of the first coating at -30°C is smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0222] (Article 5)

[0223] The multi-core cable according to clause 3 or clause 4, wherein the second coating layer contains a polyurethane resin including one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide and talc.

[0224] (Article 6)

[0225] A multi-core cable, comprising:

[0226] a plurality of coated wires including power wires and twisted pair signal wires; and

[0227] an outer coating covering the outer periphery of the plurality of covered electric wires,

[0228] The power line includes a plurality of conductors twisted together and an insulating layer covering the plurality of conductors.

[0229] Wherein, the twisted pair signal line includes two signal lines twisted together,

[0230] The outer coating includes a first coating layer and a second coating layer in order from the side of the plurality of covered electric wires.

[0231] wherein the second coating layer is composed only of a polyurethane resin, the polyurethane resin includes one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide and talc, and the storage modulus of the second coating layer at -30°C is greater than 100 MPa and less than 600 MPa, and

[0232] Wherein, the storage modulus of the first coating at -30°C is smaller than the storage modulus of the outer surface of the outer coating at -30°C.

[0233] Description of Reference Numerals

[0234] 10, 20, 30, 42: multi-core cable

[0235] 11: Power cord

[0236] 111: First conductor

[0237] 112: First insulation layer

[0238] 12: Twisted pair signal line

[0239] 121: Signal line

[0240] 1211: Second conductor

[0241] 1212: Second insulation layer

[0242] 13, 23, 33: core

[0243] 14: External coating

[0244] 141: First coating

[0245] 142: Second coating

[0246] 14A: Outer surface

[0247] 14B: Inner surface

[0248] 15: Suppression Volume

[0249] 16: Region

[0250] 21: Wires

[0251] 211: Third conductor

[0252] 212: The third insulation layer

[0253] 411, 412: Mandrel

[0254] A: Dashed line

[0255] B: Dashed line

[0256] L1: Distance

[0257] L2: Distance

[0258] X: Area

[0259] Y: area

Claims

1. A multi-core cable, comprising: A plurality of covered electrical wires; and an outer coating covering the outer periphery of the plurality of covered electric wires, Each of the plurality of covered electric wires comprises a conductor and an insulating layer covering the conductor. The storage modulus of the outer film at -30°C is 300 MPa or more and 400 MPa or less within a range of 0.1 mm from the outer surface of the outer film and within a range of 0.1 mm from the inner surface of the outer film, and The outer coating film is made of a polyolefin-based resin, a polyurethane elastomer, a polyester elastomer, or a composition obtained by mixing at least two of these materials.

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