JP6962436B2 - Multi-core cable - Google Patents

Description

The present disclosure relates to a multi-core cable.

Patent Document 1 discloses a multi-core cable for a vehicle having two coated electric wires and a jacket covering the two coated electric wires.

JP-A-2018-32515

According to one aspect of the present disclosure, a plurality of covered wires and
It has an outer peripheral coating that covers the outer circumference of the plurality of covered electric wires.
The coated electric wire has a conductor and an insulating layer covering the conductor.
Provided is a multi-core cable having an elastic modulus of the outer peripheral coating at −30 ° C. of 100 MPa or more and 600 MPa or less in a range of 0.1 mm from the outer surface of the outer peripheral coating.

FIG. 1 is a cross-sectional view perpendicular to the longitudinal direction of the multi-core cable according to one aspect of the present disclosure. FIG. 2 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 present disclosure. FIG. 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 present disclosure. FIG. 4 is a diagram schematically showing a method of bending resistance test in an experimental example.

[Issues to be solved by this disclosure]
The wheels are supported so as to be displaceable with respect to the vehicle body, and the position of the wheels is displaced with respect to the vehicle body when the vehicle is used. The multi-core cable connecting to the electric parking brake or the like may be repeatedly bent. Therefore, from the viewpoint of increasing the durability of the multi-core cable, high bending resistance has been required.

An object of the present disclosure is to provide a multi-core cable having excellent bending resistance.

[Effect of the present disclosure]
According to the present disclosure, it is possible to provide a multi-core cable having excellent bending resistance.

The embodiment for carrying out will be described below.

[Explanation of Embodiments of the present disclosure]
First, embodiments of the present disclosure will be listed and described. In the following description, the same or corresponding elements are designated by the same reference numerals, and the same description is not repeated for them.

(1) The multi-core cable according to one aspect of the present disclosure includes a plurality of covered electric wires and
It has an outer peripheral coating that covers the outer circumference of the plurality of covered electric wires.
The coated electric wire has a conductor and an insulating layer covering the conductor.
The elastic modulus of the outer peripheral coating at −30 ° C. in the range of 0.1 mm from the outer surface of the outer peripheral coating is 100 MPa or more and 600 MPa or less.

By setting the elastic modulus of the outer peripheral coating at −30 ° C. in the range of 0.1 mm from the outer surface of the outer peripheral coating to 600 MPa or less, sufficient flexibility can be imparted to the outer surface side of the outer peripheral coating. By imparting sufficient flexibility to the outer surface side of the outer peripheral coating in this way, the outer surface side of the outer peripheral 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 peripheral coating does not hinder the deformation inside the multi-core cable, so that the covered electric wire such as the power line inside the multi-core cable is suppressed from being broken, and the bending resistance is improved. It is thought that it can be enhanced.

Then, especially in a sub-zero environment, the elastic modulus of the outer peripheral coating decreases, and the multi-core cable is less likely to be deformed by following a force applied from the outside, but even in such an environment, bending resistance is improved. It is required to increase. Therefore, as described above, it is preferable that the elastic modulus of the outer peripheral coating in the above region at −30 ° C. satisfies the above range.

However, the outer peripheral coating also has a function of protecting the coated electric wire from flying objects such as stepping stones and preventing the coated electric wire from being damaged. Therefore, for example, when a stepping stone or the like collides with the outer periphery of the multi-core cable, from the viewpoint of protecting the coated electric wire such as the internal power line, the outer peripheral coating is at −30 ° C. within a range of 0.1 mm from the outer surface of the outer coating. The elastic modulus of is preferably 100 MPa or more.

(2) The elastic modulus of the resin material of the outer peripheral coating at −30 ° C. within a range of 0.1 mm from the inner surface of the outer peripheral coating located on the side of the plurality of coated electric wires is −3 of the outer surface of the outer peripheral coating. It may be lower than the elastic modulus at 30 ° C.

(3) The outer peripheral coating has a first coating layer and a second coating layer in order from the side of the plurality of coated electric wires.
The elastic modulus of the second coating layer at −30 ° C. may be 100 MPa or more and 600 MPa or less.

(4) The elastic modulus of the first coating layer at −30 ° C. may be lower than the elastic modulus of the outer surface of the outer peripheral coating at −30 ° C.

(5) The second coating layer may contain a polyurethane resin containing one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc.

(6) The multi-core cable according to one aspect of the present disclosure includes a power line, a plurality of covered electric wires including a twisted signal line, and a plurality of covered electric wires.
It has an outer peripheral coating that covers the outer circumference of the plurality of covered electric wires.
The power line has a plurality of twisted conductors and an insulating layer covering the plurality of conductors.
The anti-twisted signal line has two twisted signal lines.
The outer peripheral coating has a first coating layer and a second coating layer in order from the side of the plurality of coated electric wires.
The second coating layer is composed of only a polyurethane resin containing at least one selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc, and has an elastic modulus of 100 MPa or more and 600 MPa or less at −30 ° C. ,
The elastic modulus of the first coating layer at −30 ° C. is lower than the elastic modulus of the outer surface of the outer peripheral coating at −30 ° C.

[Details of Embodiments of the present disclosure]
A specific example of the multi-core cable according to one embodiment of the present disclosure (hereinafter referred to as “the present embodiment”) will be described below with reference to the drawings. It should be noted that the present invention is not limited to these examples, and is indicated by the claims of the patent, and is intended to include all modifications within the meaning and scope equivalent to the claims.

First, the configuration of the multi-core cable of this embodiment will be described with reference to FIGS. 1 to 3.

FIG. 1 shows a cross-sectional view of the multi-core cable 10 of the present embodiment in a plane perpendicular to the longitudinal direction.

As shown in FIG. 1, the multi-core cable 10 of the present embodiment can have a plurality of covered electric wires. The coated wire has a conductor and an insulating layer covering the conductor. FIG. 1 shows an example in which two power lines 11 and a twisted signal line 12 including two signal lines 121 are provided as a plurality of covered electric wires, but the multi-core cable of the present embodiment is shown as an example. The configuration of the plurality of covered electric wires included is not limited to such a form.

Further, the multi-core cable 10 of the present embodiment may have an outer peripheral coating 14 that covers the outer circumferences of a plurality of covered electric wires. Then, the elastic modulus of the outer peripheral coating 14 at −30 ° C. in the range of 0.1 mm from the outer surface 14A of the outer peripheral coating 14 can be set to 100 MPa or more and 600 MPa or less.

As described above, the plurality of covered electric wires included in the multi-core cable of the present embodiment are not limited to the configuration example shown in FIG. 1, and are covered with an arbitrary configuration depending on the equipment to which the multi-core cable is connected. Any number of electric wires can be provided. Other configuration examples of the plurality of covered electric wires included in the multi-core cable of the present embodiment will be described below.

FIG. 2 shows a cross-sectional view of the multi-core cable 20 of the other configuration example of the present embodiment in a plane perpendicular to the longitudinal direction, and FIG. 3 shows a cross-sectional view perpendicular to the longitudinal direction of the multi-core cable 30 of the other configuration example of the present embodiment. A cross-sectional view of each of the planes is shown.

For example, the multi-core cable 20 shown in FIG. 2 further has one electric wire 21 in addition to the two power lines 11 and the twisted signal line 12 including the two signal lines 121. Further, for example, the multi-core cable 30 shown in FIG. 3 has two power lines 11 and two twisted signal lines 12 including two signal lines 121. As described above, the multi-core cable can have an arbitrary number of covered electric wires having an arbitrary configuration.

Hereinafter, various members included in the multi-core cable of the present embodiment will be described.

(1) Covered Wire As described above, the multi-core cable of the present embodiment may have a plurality of covered wires. The configuration of the plurality of covered electric wires is not particularly limited, and the configuration can be arbitrarily selected according to the equipment to be connected, the voltage to be applied, and the like. The multi-core cable of the present embodiment may include, for example, one or more types of covered electric wires selected from power lines, signal lines, electric wires, and the like.

As the covered electric wire, a configuration example of a power line, a signal line, and an electric wire will be described below.

(1-1) Power Line The power line 11 can include a first conductor 111 and a first insulating layer 112 that covers the first conductor 111. The multi-core cable 10, the multi-core cable 20, and the multi-core cable 30 shown in FIGS. 1 to 3 each include two power lines 11, and the two power lines have the same size and material. can do.

The two power lines 11 can be used, for example, to connect an electric parking brake (EPB) and an electronic control unit (Electric Control Unit: ECU). The EPB has a motor that drives the brake caliper. For example, one power line 11 can be used as a feeder for supplying power to the motor, and the other power line 11 can be used as a ground line for the motor.

The first conductor 111 can be formed by twisting a plurality of conductors. As the conductor, a wire composed of copper or a copper alloy can be used. In addition to copper and copper alloys, the conductor can be made of a material having predetermined conductivity and flexibility, such as tin-plated annealed copper wire and annealed copper wire. The conductor may be made of hard copper wire. The cross-sectional area of the first conductor 111 ^{can be 1.4 mm 2} or more and 3 mm ² or less. The power line 11 may also have a plurality of first conductors 111.

The first insulating layer 112 can be formed of a composition containing 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" means the average value of the thickness measured at any ten points. In the following, the term "average thickness" for other members and the like is also defined in the same manner.

The main component of the first insulating layer 112 is not particularly limited as long as it has insulating properties, but from the viewpoint of improving bending resistance at low temperatures, a copolymer of ethylene and an α-olefin having a carbonyl group (hereinafter referred to as a copolymer). , Also referred to as the main component resin) is preferable. The lower limit of the α-olefin content having a carbonyl group of the main component resin is preferably 14% by mass, more preferably 15% by mass. On the other hand, the upper limit of the α-olefin content having a carbonyl group is preferably 46% by mass, more preferably 30% by mass. By setting the content of the α-olefin having a carbonyl group to the above lower limit or more, the bending resistance at low temperature can be particularly enhanced, which is preferable. Further, by setting the content of the α-olefin having a carbonyl group to the above upper limit or less, the mechanical properties such as the strength of the first insulating layer 112 can be enhanced, which is preferable.

Examples of the α-olefin having a carbonyl group include (meth) acrylic acid alkyl esters such as methyl (meth) acrylate and (meth) ethyl acrylate; (meth) acrylic acid aryl esters such as (meth) phenyl acrylate; vinyl acetate. , Vinyl esters such as vinyl propionate; unsaturated acids such as (meth) acrylic acid, crotonic acid, maleic acid, and itaconic acid; vinyl ketones such as methyl vinyl ketone and phenyl vinyl ketone; selected from (meth) acrylic acid amide and the like. It is preferable to include one or more types. Among these, one or more selected from (meth) acrylic acid alkyl ester and vinyl ester are more preferable, and one or more selected from ethyl acrylate and vinyl acetate are further preferable.

Examples of the main component resin include ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate copolymer (EMA), and ethylene-butyl acrylate copolymer (EBA). ) And the like, and among these, one or more selected from EVA and EEA are preferable.

The first insulating layer 112 may contain additives such as a flame retardant, a flame retardant aid, an antioxidant, a lubricant, a colorant, a reflection imparting agent, a concealing agent, a processing stabilizer, and a plasticizer. Further, the first insulating layer 112 may contain a resin other than the main component resin.

The upper limit of the content of the other resin is preferably 50% by mass, more preferably 30% by mass, still more preferably 10% by mass. Further, the first insulating layer 112 does not have to substantially contain other resins.

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

Examples of the brominated flame retardant include decabromodiphenylethane and the like. Examples of the chlorine-based flame retardant include chlorinated paraffin, chlorinated polyethylene, chlorinated polyphenol, and perchlorpentacyclodecane. Examples of the metal hydroxide include magnesium hydroxide and aluminum hydroxide. Examples of the nitrogen-based flame retardant include melamine cyanurate, triazine, isocyanurate, urea, guanidine and the like. Examples of the phosphorus-based flame retardant include phosphinic acid metal salt, phosphaphenanthrene, melamine phosphate, ammonium phosphate, phosphoric acid ester, polyphosphazene and the like.

As the flame retardant, a non-halogen flame retardant is preferable from the viewpoint of reducing the environmental load, and a metal hydroxide, a nitrogen flame retardant and a phosphorus flame retardant are more preferable.

When the first insulating layer 112 contains a flame retardant, the lower limit of the content of the flame retardant in the first insulating layer 112 is preferably 10 parts by mass, more preferably 50 parts by mass, based on 100 parts by mass of the resin component. preferable. On the other hand, the upper limit of the content of the flame retardant is preferably 200 parts by mass and more preferably 130 parts by mass with respect to 100 parts by mass of the resin component. If the content of the flame retardant is less than the above lower limit, the flame retardant effect may not be sufficiently imparted. On the contrary, if the content of the flame retardant exceeds the above upper limit, the extrusion moldability of the first insulating layer 112 may be impaired, and the mechanical properties such as elongation and tensile strength may be impaired.

The first insulating layer 112 is preferably crosslinked with a resin component. Examples of the method of cross-linking the resin component of the first insulating layer 112 include a method of irradiating ionizing radiation, a method of using a thermal cross-linking agent, a method of using a silane grafter, and the like, and a method of irradiating ionizing radiation is preferable. Further, in order to promote cross-linking, it is preferable to add a silane coupling agent to the composition forming the first insulating layer 112.

(1-2) Signal line The signal line 121 includes a second conductor 1211 that is thinner than the first conductor 111, and a second insulating layer 1212 that covers the second conductor 1211. The signal lines 121 can be twisted in pairs to form a pair twisted signal line 12. The two signal lines 121 twisted along the longitudinal direction can be of the same size and material as each other. The twist pitch of the anti-twist signal wire 12 is not particularly limited, but can be, for example, 4 times or more and 10 times or less the twist diameter of the anti-twist signal wire 12 (outer diameter of the anti-twist signal wire 12).

When the multi-core cable has a power line 11 and a twisted signal line 12, the outer diameter of the twisted signal line 12 can be substantially the same as the outer diameter of the power line 11.

The signal line 121 can be used for transmitting a signal from the sensor, or can be used for transmitting a control signal from the ECU. The two signal lines 121 can be used, for example, for wiring an anti-lock brake system (ABS). Each of the two signal lines 121 can be used, for example, as a line connecting the differential wheel speed sensor and the ECU of the vehicle. The two signal lines 121 may be used for transmission of other signals.

The second conductor 1211 may be composed of one conductor, or may be formed by twisting a plurality of conductors like the power line 11. The second conductor 1211 may be made of the same material as the conductor constituting the first conductor 111 described above, or may use 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 or more and 0.5 mm ² or less. The signal line 121 may also have a plurality of second conductors 1211.

The material of the second insulating layer 1212 is not particularly limited, and can be formed of, for example, a flame-retardant polyolefin resin such as cross-linked polyethylene to which flame retardancy is imparted by blending a flame retardant. The material constituting the second insulating layer 1212 is not limited to the flame-retardant polyolefin-based resin, and may be formed of another material such as a crosslinked fluorine-based resin. The outer diameter of the second insulating layer 1212 can be, for example, 1.0 mm or more and 2.2 mm or less.

(1-3) Electric Wire As shown in the multi-core cable 20 of FIG. 2, the multi-core cable of the present embodiment may have an electric wire 21 as a covered electric wire.

The electric wire 21 includes a third conductor 211 that is thinner than the first conductor 111, and a third insulating layer 212 that covers the third conductor 211. The electric wire 21 may have the same size and material as the signal line 121.

The electric wire 21 can be used for transmitting a signal from a sensor, can be used for transmitting a control signal from an ECU, and can also be used as a feeding line for supplying power to an electronic device. .. The electric wire 21 can also be used as a ground wire.

The third conductor 211 may be composed of one conductor, or may be formed by twisting a plurality of conductors like the power line 11. The third conductor 211 may be made of the same material as the conductors constituting the first conductor 111 and the second conductor 1211, or may use different materials. The cross-sectional area of the third conductor 211 is not particularly limited, but may be, for example, 0.13 mm ² or more and 0.5 mm ² or less. The electric wire 21 may also have a plurality of third conductors 211.

The third insulating layer 212 may use the same material as the second insulating layer 1212, or may use a different material. The outer diameter of the third insulating layer 212 can be 1.0 mm or more and 2.2 mm or less.

Two electric wires 21 may be used, and these may be twisted to form a countertwisted electric wire. In this case, it is preferable that the two electric wires 21 to be twisted have the same size and material. When the electric wire is a twisted electric wire and is arranged in the multi-core cable together with the twisted signal wire, the twisted electric wire is preferably twisted in the same direction as the twisted signal wire 12. Further, in this case, it is preferable that the twisted electric wire has the same twist pitch as the twisted signal wire 12. The outer diameter of the anti-twisted electric wire can be substantially the same as the outer diameter of the anti-twisted signal wire 12. The outer diameter of the anti-twisted wire can be substantially the same as the outer diameter of the power line 11.

As described above, the configuration of the plurality of coated electric wires included in the multi-core cable of the present embodiment is not particularly limited, and an arbitrary number of coated electric wires having an arbitrary configuration can be used depending on the device or the like to which the multi-core cable is connected. Can have. However, like the multi-core cables 10, 20, and 30 shown in FIGS. 1 to 3, the multi-core cable preferably has a plurality of covered electric wires including a power line 11 and a twisted signal line 12. This is because a multi-core cable including a power line 11 and a twisted signal line 12 can be used as a highly versatile multi-core cable that can be used for various purposes.

The power line 11 and the anti-twisted signal line 12 can have the above-described configuration. For example, the power line can have a plurality of twisted conductors and an insulating layer covering the plurality of conductors. Further, the anti-twisted signal line 12 can have two twisted signal lines.

Although power lines, signal lines, and electric wires have been described as examples of covered electric wires so far, the first conductor 111, the second conductor 1211, and the third conductor 211 in the above description are the above-mentioned covered electric wires. It hits the conductor. Further, the first insulating layer 112, the second insulating layer 1212, and the third insulating layer 212 correspond to the insulating layer of the covered electric wire described above.

(2) Peripheral coating As described above, the multi-core cable of the present embodiment can include a plurality of coated electric wires selected from the power line 11, the signal line 121, the electric wire 21, and the like. Then, the plurality of covered electric wires can be integrally twisted along the longitudinal direction to form a core.

Specifically, for example, in the case of the multi-core cable 10 shown in FIG. 1, two power lines 11 and one anti-twisted signal line 12 can be twisted to form a core 13. Further, in the case of the multi-core cable 20 shown in FIG. 2, the core 23 can be formed by twisting two power lines 11, one anti-twisted signal line 12, and an electric wire 21. In the case of the multi-core cable 30 shown in FIG. 3, the core 33 can be formed by twisting the two power lines 11 and the two anti-twisted signal lines 12.

The total twist diameter of the core obtained by twisting a plurality of coated electric wires can be, for example, 5.5 mm or more and 9 mm or less.

Further, the twist pitch of the core obtained by twisting a plurality of coated electric wires is not particularly limited, but can be, for example, 12 times or more and 24 times or less the twist diameter of the core. By setting the twist pitch of the core to 24 times or less the twist diameter of the core, it is possible to suppress loosening of the twist and particularly improve the bending resistance. Further, by setting the twist pitch of the core to 12 times or more the twist diameter of the core, the productivity of the multi-core cable can be particularly increased.

When the core includes the anti-twist signal wire 12, the ratio of the twist pitch of the core to the core twist diameter is preferably larger than the ratio of the twist pitch of the anti-twist signal wire 12 to the twist diameter of the anti-twist signal wire 12. .. The twisting direction of the core is not particularly limited, but is preferably the same as the twisting direction of the anti-twist signal line 12.

The multi-core cable of the present embodiment may have a plurality of coated electric wires, that is, an outer peripheral coating 14 that covers the outer periphery of the core. At this time, the outer peripheral coating 14 can be arranged so as to completely cover the plurality of coated electric wires, that is, the core.

According to the study by the inventors of the present invention, the elastic modulus of the outer peripheral coating 14 at −30 ° C. in the range of 0.1 mm from the outer surface 14A of the outer peripheral coating 14 is set to 100 MPa or more and 600 MPa or less. The bending resistance of the multi-core cable can be particularly improved.

As shown in FIGS. 1 to 3, the region X is defined as the area between the outer surface 14A of the outer peripheral coating 14 and the dotted line A at which the distance L1 from the outer surface 14A is 0.1 mm. In the cross section perpendicular to the longitudinal direction of the multi-core cable, the outer surface 14A of the multi-core cable is usually circular, and the dotted line A having a distance L1 from the outer surface 14A of 0.1 mm is outside along the outer surface 14A. Since the shape is the same as that of the surface 14A, the region X has an annular shape. The "circle" regarding the shape of the outer surface 14A of the multi-core cable in the cross section perpendicular to the longitudinal direction of the multi-core cable does not mean only a circle in a strict sense, that is, a perfect circle, but a multi-core cable. Includes tolerances allowed in, including non-perfect circles such as ellipses.

In this case, the elastic modulus of the outer peripheral coating 14 in the region X at −30 ° C. is preferably 100 MPa or more and 600 MPa or less, and more preferably 300 MPa or more and 500 MPa or less.

As described above, the multi-core cable is used in a vehicle such as an automobile, but the multi-core cable may be repeatedly bent when the vehicle is used. Therefore, from the viewpoint of increasing the durability of the multi-core cable, high bending resistance has been required. A multi-core cable having high bending resistance is the number of repeated bendings required for the coated electric wire of the multi-core cable to crack or break when the multi-core cable is repeatedly bent to increase the resistance value. Means a multi-core cable with many.

Therefore, as a result of diligent studies by the inventors of the present invention, the elastic modulus of the outer peripheral coating in the above-mentioned region X at −30 ° C. is set to 600 MPa or less, so that the outer surface side of the outer peripheral coating is sufficiently flexible. Gender can be imparted. By imparting sufficient flexibility to the outer surface side of the outer peripheral coating in this way, the outer surface side of the outer peripheral 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 deformation inside the multi-core cable is not hindered, so that the covered electric wire such as the power line inside the multi-core cable can be suppressed from being broken and the bending resistance can be improved. it is conceivable that.

Then, especially in a sub-zero environment, the elastic modulus of the outer peripheral coating decreases, and the multi-core cable is less likely to be deformed by following a force applied from the outside, but even in such an environment, bending resistance is improved. It is required to increase. Therefore, as described above, it is preferable that the elastic modulus of the outer peripheral coating of the region X at −30 ° C. satisfies the above range.

However, the outer peripheral coating also has a function of protecting the coated electric wire from flying objects such as stepping stones and preventing the coated electric wire from being damaged. Therefore, for example, when a stepping stone or the like collides with the outer circumference of the multi-core cable, the elastic modulus of the outer peripheral coating in the above-mentioned region X at −30 ° C. is 100 MPa or more from the viewpoint of protecting the coated electric wire such as the internal power line. It is preferable to have.

In the outer peripheral coating 14, not only the region X but the entire outer peripheral coating 14 may satisfy the preferable range of the elastic modulus.

However, in the multi-core cable of the present embodiment, the elastic modulus of the resin material of the outer peripheral coating 14 at −30 ° C. in the range of 0.1 mm from the inner surface 14B located on the side of the plurality of covered electric wires of the outer peripheral coating 14 is determined. It is preferably lower than the elastic modulus of the outer surface 14A of the outer peripheral coating 14 at −30 ° C.

As shown in FIGS. 1 to 3, the region Y is between the inner surface 14B located on the side of the plurality of covered electric wires of the outer peripheral coating 14 and the dotted line B having a distance L2 from the inner surface 14B of 0.1 mm. And. In this case, it is preferable that the elastic modulus of the resin material of the outer peripheral coating 14 in the region Y at −30 ° C. is lower than the elastic modulus of the outer surface 14A of the outer peripheral coating 14 at −30 ° C.

This is the elastic modulus of the resin material of the outer peripheral coating 14 at −30 ° C. in the region Y located on the side of the plurality of covered electric wires such as the power line 11 in the outer peripheral coating 14, and the elastic modulus of −30 of the outer surface 14A of the outer peripheral coating 14. By lowering the elastic modulus at ° C., the flexibility of the outer peripheral coating 14 in the region Y can be particularly increased. Therefore, even when a plurality of covered electric wires such as the power line 11 are displaced or deformed, the displacement of the outer peripheral coating 14 of the region Y can be absorbed. Therefore, it is possible to particularly suppress disconnection of a plurality of covered electric wires and particularly improve the bending resistance of the multi-core cable.

The specific range of the elastic modulus of the resin material of the outer peripheral coating 14 in the region Y at −30 ° C. is not particularly limited, but is preferably 500 MPa or less, more preferably 400 MPa or less, for example.

As described above, since the outer peripheral coating 14 also has a function of protecting a plurality of covered electric wires, the elastic modulus of the resin material of the outer peripheral coating 14 in the region Y at −30 ° C. is 10 MPa or more. Is preferable, and 100 MPa or more is more preferable.

The structure of the outer peripheral coating 14 is not particularly limited, and may be composed of a plurality of layers made of different materials so as to have a desired elastic modulus. Further, the outer peripheral coating 14 may be composed of one layer.

Specifically, for example, the outer peripheral coating 14 may have 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 power lines 11.

By forming the outer peripheral coating 14 from a plurality of layers in this way, the elastic modulus thereof can be easily adjusted according to the location of the outer peripheral coating 14, which is preferable.

When the outer peripheral coating 14 has the first coating layer 141 and the second coating layer 142 as described above, for example, the elastic modulus of the second coating layer 142 at −30 ° C. is set to 100 MPa or more and 600 MPa or less. It is preferably 300 MPa or more and 500 MPa or less.

This is because, for example, by setting the elastic modulus of the second coating layer 142 in the above range, the elastic modulus of the outer peripheral coating in the above-mentioned region X can be easily set in a desired range. In this case, it is preferable that the second coating layer 142 is configured to include, for example, the outer surface 14A of the outer peripheral coating 14. That is, it is preferable that the second coating layer 142 is arranged on the outermost peripheral side of the outer peripheral coating 14.

The thickness of the second coating layer 142 is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.3 mm or more, for example. The upper limit of the thickness of the second coating layer 142 is not particularly limited, but is preferably 1.0 mm or less, more preferably 0.8 mm or less, for example.

Further, when the outer peripheral coating 14 has the first coating layer 141 and the second coating layer 142 as described above, for example, the elastic modulus of the first coating layer 141 at −30 ° C. is the outer peripheral coating 14. It is preferable that the elastic modulus of the outer surface 14A of the above surface is lower than the elastic modulus at −30 ° C.

This is because, for example, by setting the elastic modulus of the first coating layer 141 within the above range, the elastic modulus of the above-mentioned region Y can be easily set within a desired range. In this case, it is preferable that the first coating layer 141 is configured to include, for example, the inner surface 14B of the outer peripheral coating 14. That is, it is preferable that the first coating layer 141 is arranged on the innermost peripheral side of the outer peripheral coating 14, in other words, on the side of a plurality of coated electric wires.

The thickness of the first coating layer 141 is not particularly limited, but is preferably 0.1 mm or more, more preferably 0.3 mm or more, for example. The upper limit of the thickness of the first coating layer 141 is not particularly limited, but is preferably 1.0 mm or less, more preferably 0.8 mm or less, for example.

The specific range of the elastic modulus of the first coating layer 141 at −30 ° C. is not particularly limited, but is preferably 500 MPa or less, more preferably 400 MPa or less, for example. The lower limit of the elastic modulus of the first coating layer 141 at −30 ° C. is not particularly limited, but is preferably, for example, 10 MPa or more, and more preferably 100 MPa or more.

The material of the outer peripheral coating 14 is not particularly limited, but is, for example, a polyolefin resin such as polyethylene or ethylene-vinyl acetate copolymer (EVA), a polyurethane elastomer, a polyester elastomer, or a composition formed by mixing at least two of these. It can be formed of objects. Further, the outer peripheral coating 14 may be made of, for example, a crosslinked / non-crosslinked thermoplastic polyurethane (TPU) having excellent wear resistance. Since the outer peripheral coating 14 is excellent in heat resistance, it is preferable that the outer peripheral coating 14 is made of crosslinked thermoplastic polyurethane.

The specific method for setting the elastic modulus of the outer peripheral coating 14 at −30 ° C. in a desired range is not particularly limited, and for example, the desired elastic modulus can be obtained by selecting the material constituting the outer peripheral coating 14. Further, the elastic modulus can be adjusted by blending an inorganic substance such as a flame retardant with the resin material of the outer peripheral coating 14. When an inorganic substance such as a flame retardant is blended with the resin material of the outer peripheral coating 14, the blending ratio is not particularly limited, but for example, the amount of the inorganic substance such as a flame retardant is 12 parts by mass or less with respect to 100 parts by mass of the resin material. It is preferable to add it in such a manner, and it is more preferable to add it in an amount of 10 parts by mass or less.

If the amount of the inorganic substance added to 100 parts by mass of the resin material is excessive, the elastic modulus may increase. Therefore, the amount of the inorganic substance added is preferably 12 parts by mass or less.

Examples of the inorganic substance to be added include one or more selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc.

The outer peripheral coating 14 may also have a first coating layer 141 and a 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. Further, for example, the elastic modulus of each layer can be adjusted by changing the addition amount of an additive of an inorganic substance such as a flame retardant between the first coating layer 141 and the second coating layer 142.

The materials of the first coating layer 141 and the second coating layer 142 are not particularly limited, and for example, the materials described for the outer peripheral coating 14 described above can be used.

As the material of the first coating layer 141, one or more selected from polyurethane resin and polyethylene resin can be preferably used. In order to adjust the elastic modulus as described above, the first coating layer 141 may further contain an inorganic substance such as a flame retardant, if necessary.

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

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

By forming the second coating layer 142 with the above material, the durability of the multi-core cable can be particularly enhanced, and the elastic modulus of the second coating layer 142 can be easily adjusted.

The multi-core cable of the present embodiment may further have an arbitrary member other than the plurality of coated electric wires described above and the outer peripheral coating.

For example, it may have a holding winding 15 that covers the outer periphery of a plurality of covered electric wires. The restraint winding 15 covers a core in which a plurality of coated electric wires are twisted together. By arranging the holding winding 15, the twisted shape of the plurality of covered electric wires constituting the core can be stably maintained. The holding roll 15 can be provided inside the outer peripheral coating 14.

As the holding roll 15, for example, a paper tape, a non-woven fabric, or a resin tape such as polyester can be used. Further, the holding roll 15 may be spirally wound along the longitudinal direction of the core, or may be vertically attached, that is, the holding paper may be arranged vertically along the longitudinal direction of the core. Further, the winding direction may be Z winding or S winding. When the core 13 includes the twisted signal wire 12 and the like, the winding direction of the restraint winding 15 may be the same as the twisted direction of the twisted signal wire 12 and the like included in the core 13, or may be wound in the opposite direction. You may roll it. However, it is preferable to reverse the winding direction of the restraint winding 15 and the twisted pair direction of the anti-twisted signal wire 12 or the like because the surface of the restraint winding 15 is less likely to be uneven and the outer diameter shape of the multi-core cable is easily stabilized.

Since the holding roll 15 has a function of enhancing the flexibility by having a buffering action and a function of protecting from the outside, the layer of the outer peripheral coating 14 can be formed thin when the holding roll 15 is provided. By providing the holding winding 15 in this way, it is possible to provide a multi-core cable that is more easily bent and has excellent wear resistance.

Further, when a resin outer peripheral coating 14 or the like is provided by extrusion coating, the resin may enter between a plurality of coated electric wires, and it may be difficult to separate the plurality of coated electric wires at the end of the multi-core cable. .. Therefore, by providing the holding winding 15, it is possible to prevent the resin from entering between the plurality of coated electric wires, and to make it easier to take out the plurality of coated electric wires such as power lines at the terminal.

Further, the multi-core cable of the present embodiment may have an interposition in a region 16 between the outer peripheral coating 14 and the core, for example. The interposition can be composed of fibers such as rayon and nylon yarn. The interposition may be composed of tensile strength fibers.

The interposition can be arranged in a gap formed between the covered electric wires, such as between the power lines 11 and between the power lines 11 and the signal lines 121.

Although the embodiments have been described in detail above, the embodiments are not limited to the specific embodiments, and various modifications and changes can be made within the scope of the claims.

Specific examples will be described below, but the present invention is not limited to these examples.
(Evaluation method)
First, an evaluation method of the multi-core cable produced in the following experimental example will be described.
(1) Evaluation of elastic modulus of outer peripheral coating In each of the following experimental examples, the same resin (composition) as the resin (composition) used when forming the outer peripheral coating 14 was melt-extruded and sampled for measuring the elastic modulus. Was produced. In Experimental Example 1, since the outer peripheral coating 14 having the first coating layer 141 and the second coating layer 142 was formed, two elastic moduli were used using the same resin as the resin used when forming each coating layer. A sample for measurement was prepared.

For each sample prepared, in accordance with JIS-K7244-1 (1998), using a dynamic viscoelasticity measuring device (“DVA200” of IT Measurement Control Co., Ltd.), strain 0.08%, frequency 10 Hz, The storage elastic modulus was measured in the range of −50 ° C. to 200 ° C. under the condition of a heating rate of 10 ° C./min.

In Experimental Example 1, the storage elastic modulus at −30 ° C. for the same resin as the resin used for forming the first coating layer 141 obtained by this measurement was −30 of the first coating layer 141. It is the elastic modulus at ° C. Further, the storage elastic modulus of the same resin as the resin used for forming the second coating layer 142 obtained by this measurement at −30 ° C. is the storage elastic modulus of the second coating layer 142 at −30 ° C. It becomes the elastic modulus.

In Experimental Example 2, the storage elastic modulus of the same resin as the resin used for forming the outer peripheral coating 14 obtained by this measurement at −30 ° C. is the elastic modulus of the outer peripheral coating 14 at −30 ° C. Become.
(2) Bending resistance test The multi-core cable obtained in the following experimental example was subjected to a bending resistance test by a method according to JIS C 6851 (2006) (optical fiber characteristic test method).

Specifically, as shown in FIG. 4, a multi-core cable 42 for evaluation is arranged vertically and sandwiched between two mandrels 411 and 412 having a diameter of 60 mm arranged horizontally and parallel to each other. After bending the upper end 90 ° horizontally so as to abut the upper side of one mandrel 411, bend it 90 ° horizontally so as to abut the upper side of the other mandrel 412 in a constant temperature bath at -30 ° C. Repeated in. This repetition is performed while connecting two conductors in the cable and measuring the resistance value, and the number of times when the resistance rises to 10 times or more of the initial resistance value (after bending to the right and then to the left). , The number of times of bending is one until it returns to the right side.) Was used as the index value of the bending resistance test. The index value of the bending resistance test, that is, the larger the number of bendings, the better the bending resistance.
(Experimental example)
The experimental conditions will be described below. Experimental Example 1 is an example, and Experimental Example 2 is a comparative example.
[Experimental Example 1]
The multi-core cable 10 shown in FIG. 1 was produced and evaluated. Specifically, the core 13 includes two power lines 11 and a twisted signal line 12 including two signal lines 121.

The power line 11 includes seven first conductors 111. The first conductor 111 is composed of 48 conductors twisted together, and the outer diameter of the first conductor 111 is 2.7 mm and the cross-sectional area is 1.7 mm ² .

The anti-twisted signal line 12 is formed by twisting a signal line 121 including three second conductors 1211. The second conductor 1211 is composed of 16 conductors twisted together, and the second conductor 1211 has an outer diameter of 1.6 mm and a cross-sectional area of 0.25 mm ² .

The core 13 is formed by twisting the above-mentioned two power lines 11 and a twisted signal line 12 along the longitudinal direction. A thin paper is arranged around the core 13 as a holding roll 15, and an outer peripheral coating 14 is arranged so as to cover the core 13.

The outer peripheral coating 14 has a first coating layer 141 and a second coating layer 142. The first coating layer 141 had a thickness of 0.65 mm and was formed of a polyethylene resin. The second coating layer 142 had a thickness of 0.5 mm, and was formed of a material obtained by adding antimony trioxide, which is an inorganic substance, to 100 parts by mass of the polyurethane resin at a ratio of 12 parts by mass to 100 parts by mass of the polyurethane resin.

The elastic modulus of the polyethylene resin used for forming the first coating layer 141 at −30 ° C. was measured and found to be 200 MPa (shown as “elastic modulus of the first coating layer” in Table 1). ). Therefore, the elastic modulus of the outer peripheral coating 14 in the region Y of FIG. 1 at −30 ° C. is 200 MPa.

Further, at −30 ° C., a material in which antimony trioxide, which is an inorganic substance, was added at a ratio of 12 parts by mass to 100 parts by mass of the polyurethane resin to the polyurethane resin used when forming the second coating layer 142. The elastic modulus was measured and found to be 400 MPa (shown as "elastic modulus of the second coating layer" in Table 1). Therefore, the elastic modulus of the outer peripheral coating 14 at −30 ° C. in the region X in FIG. 1 and the outer surface 14A is 400 MPa.

The evaluation results are shown in Table 1.
[Experimental Example 2]
The outer peripheral coating 14 was formed of a polyurethane resin by adding antimony trioxide, which is an inorganic substance, to 100 parts by mass of the polyurethane resin at a ratio of 15 parts by mass to form one layer. A multi-core cable was produced in the same manner as in the case.

The elastic modulus of a material obtained by adding antimony trioxide, which is an inorganic substance, to 100 parts by mass of the polyurethane resin to the polyurethane resin used for forming the outer peripheral coating 14 at a ratio of 15 parts by mass was measured at −30 ° C. , 650 MPa.

Therefore, the elastic modulus of the outer peripheral coating 14 at −30 ° C. in FIG. 1 is 650 MPa at any location of the outer peripheral coating 14.

The evaluation results are shown in Table 1.

表１に示した結果によれば、外周被膜１４の外表面１４Ａから０．１ｍｍの範囲、すなわち領域Ｘにおける、外周被膜１４の−３０℃での弾性率が１００ＭＰａ以上６００ＭＰａ以下である実験例１の多芯ケーブルは、上記規定を充足しない実験例２の多芯ケーブルと比較して耐屈曲性に優れることを確認できた。

According to the results shown in Table 1, Experimental Example 1 in which the elastic modulus of the outer peripheral coating 14 at −30 ° C. in the range of 0.1 mm from the outer surface 14A of the outer peripheral coating 14, that is, in the region X is 100 MPa or more and 600 MPa or less. It was confirmed that the multi-core cable of No. 2 is superior in bending resistance as compared with the multi-core cable of Experimental Example 2 which does not satisfy the above regulations.

10, 20, 30, 42 Multi-core cable 11 Power line 111 First conductor 112 First insulating layer 12 Twisted signal line 121 Signal line 1211 Second conductor 1212 Second insulating layer 13, 23, 33 Core 14 Outer circumference Coating 141 First coating layer 142 Second coating layer 14A Outer surface 14B Inner surface 15 Suppressing winding 16 Region 21 Electric wire 211 Third conductor 212 Third insulating layer 411,412 Mandrel A Dotted line B Dotted line L1 Distance L2 Distance X Area Y area

Claims (6)

With multiple covered wires,
It has an outer peripheral coating that covers the outer circumference of the plurality of covered electric wires.
The coated electric wire has a conductor and an insulating layer covering the conductor.
The storage elastic modulus of the outer peripheral coating at −30 ° C. in the range of 0.1 mm from the outer surface of the outer peripheral coating is 100 MPa or more and 600 MPa or less.
The outer peripheral coating has a first coating layer and a second coating layer in order from the side of the plurality of coated electric wires.
The second coating layer is a multi-core cable made of only a polyurethane resin containing at least one selected from antimony trioxide, aluminum hydroxide, magnesium hydroxide, and talc. The storage elastic modulus of the resin material of the outer peripheral coating at −30 ° C. within a range of 0.1 mm from the inner surface of the outer peripheral coating located on the side of the plurality of coated electric wires is −30 ° C. of the outer surface of the outer peripheral coating. The multi-core cable according to claim 1, which is lower than the storage elastic modulus in. The multi-core cable according to claim 1 or 2, wherein the storage elastic modulus of the second coating layer at −30 ° C. is 100 MPa or more and 600 MPa or less. The present invention according to any one of claims 1 to 3, wherein the storage elastic modulus of the first coating layer at −30 ° C. is lower than the storage elastic modulus of the outer surface of the outer peripheral coating at −30 ° C. Multi-core cable. The multi-core cable according to any one of claims 1 to 4, wherein the storage elastic modulus of the first coating layer at −30 ° C. is 10 MPa or more and 500 MPa or less. Any of claims 1 to 5, wherein the content of the inorganic substance contained in the first coating layer and the second coating layer differs between the first coating layer and the second coating layer. The multi-core cable described in item 1.

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