JP2023111601A - Electric cable - Google Patents

Abstract

To provide an electric cable which is excellent in heat release characteristics of heat generated on a core wire of a conductor, to an outside.SOLUTION: An electric cable 1 comprises: a conductor core wire 10; an insulation coating 20 arranged so as to surround a periphery of the conductor core wire 10; and a coat layer 30 which is arranged so as to surround a periphery of the insulation coating 20, and is formed of materials including, a base material 31, and a mixture 32 which is excellent in heat transfer properties relative to the base material 31 and is mixed with the base material 31. An outer peripheral surface of the insulation coating 20 and an inner peripheral surface of the coat layer 30 have an irregularity fitting structure in which, one of them has a salient 20A protruding toward the other, in a radial direction of the electric cable 1, and the other of them has a recess 30A which is hollow to the one of them. The electric cable 1 has a soft heat transfer body 40 which is arranged so as to fill at least a part of a gap S between the salient 20A and the recess 30A.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to an electric wire including a conductor core wire, an insulating coating arranged so as to surround the outer periphery of the conductor core wire, and a jacket layer arranged so as to surround the outer periphery of the insulating coating.

2. Description of the Related Art Conventionally, an electric wire having a structure in which a conductor core wire is covered in multiple layers with an insulating coating or an outer skin layer (so-called sheath) has been proposed as an electric wire or the like for power supply (see, for example, Patent Document 1).

JP 2019-176617 A

By the way, when an electric wire is actually used, the temperature of the conductor core generally rises due to Joule heat generated in the conductor core when the electric wire is energized. In the conventional electric wire described above, since the conductor core wire is covered with an insulating coating or the like in multiple layers, the heat generated in the conductor core wire is difficult to radiate to the outside of the electric wire. Therefore, as the temperature of the conductor core wire rises, the temperature of the entire wire also rises, and there is a possibility that the insulation coating and the outer layer will deteriorate due to heat. From the viewpoint of quality maintenance and safety of electric wires, it is desirable to suppress such deterioration.

One of the objects of the present invention is to provide an electric wire which is excellent in heat radiation characteristics to the outside of the heat generated in the conductor core wire.

In order to achieve the aforementioned objects, the electric wire according to the present invention is characterized as follows.

a conductor core wire;
an insulating coating arranged to surround the outer circumference of the conductor core wire;
An electric wire comprising a skin layer arranged to surround the outer periphery of the insulating coating,
The skin layer is
Consists of a material containing a base material and a mixture that is mixed with the base material and has better heat conductivity than the base material,
Be an electric wire.

According to the present invention, the skin layer surrounding the insulating coating that covers the conductor core wire is made of a material containing a base material and a mixture that is more excellent in heat transfer than the base material and is mixed with the base material. Therefore, heat can be efficiently transferred from the insulating coating to the outer layer and heat can be released from the outer layer to the outside of the wire more efficiently than when the outer layer is composed of only the base material. In other words, it is possible to improve the overall heat dissipation of the multilayer structure including the insulating coating and the outer skin layer. Therefore, the electric wire of this configuration is excellent in heat radiation characteristics to the outside of the heat generated in the conductor core wire.

Furthermore, as another effect, the electric wire having the above configuration has the advantage of workability and ease of wiring when wiring the electric wire, compared to the case where a heat absorbing material (for example, a metal case, etc.) is provided outside the outer skin layer. Excellent flexibility.

In addition to the above structure, by mixing a mixture having excellent heat conductivity into the material constituting the insulating coating, the overall heat dissipation of the multilayer structure can be further improved. However, by mixing such a mixture with the material that constitutes the insulating coating, the insulating properties of the insulating coating may be reduced, and the mixture may be exposed to the inner peripheral surface of the insulating coating. There is a possibility that deterioration of the insulation coating or the like may occur due to the occurrence of an electric discharge. Therefore, when maintaining the function of the insulating coating is emphasized rather than further improving heat dissipation, the outer skin layer is made of a material containing a mixture with excellent heat transfer properties, and the insulating coating is made of a material that does not contain such a mixture. preferably configured.

The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following detailed description of the invention (hereinafter referred to as "embodiment") with reference to the accompanying drawings. .

FIG. 1 is a cross-sectional view of an electric wire according to a first embodiment of the invention. FIG. 2 is a cross-sectional view of the electric wire according to the second embodiment. FIG. 3 is an enlarged view of part A in FIG. FIG. 4 is a cross-sectional view of the electric wire according to the third embodiment.

<First embodiment>
An electric wire 1 according to a first embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the electric wire 1 includes a linear conductor core wire 10, a cylindrical insulating coating 20 arranged so as to surround the outer periphery of the conductor core wire 10, and a cylindrical insulating coating 20 arranged so as to surround the outer periphery of the insulating coating 20. and a cylindrical outer skin layer 30. The skin layer 30 constitutes the outermost layer of the electric wire 1 and is also called a sheath.

The conductor core wire 10 may be a single conductor wire, a conductor bundle in which a plurality of conductor wires (element wires) are bundled, or a stranded wire in which a plurality of conductor wires are twisted. Here, the conducting wire is made of a conductive metal material, typically made of copper, copper alloy, aluminum, aluminum alloy, or the like.

In this example, the insulating coating 20 surrounds the outer periphery of the conductor core wire 10 so as to adhere to the entire outer periphery of the conductor core wire 10 . The insulating coating 20 is made of an insulating resin material, typically made of crosslinked polyethylene. The insulating coating 20 is formed, for example, by extruding a resin material forming the insulating coating 20 so as to surround the conductor core wire 10 .

The skin layer 30 (sheath) surrounds the outer periphery of the insulating coating 20 so as to adhere to the entire outer periphery of the insulating coating 20 in this example. The skin layer 30 is made of a material (that is, a composite material) containing an insulating base material 31 and a mixture 32 mixed with the base material 31 . The effect of mixing the mixture 32 with the base material 31 will be described later.

The base material 31 of the skin layer 30 is made of an insulating resin material, typically polyvinyl chloride or polyethylene. The mixture 32 is composed of a material that is more heat conductive than the base material 31 . As the mixture 32, for example, alumina particles or boron nitride filler can be used. The thermal conductivity of the material (composite material) including the base material 31 and the mixture 32 is preferably higher than 0.29 W/m·K.

The outer skin layer 30 is formed, for example, by extruding the insulating coating 20 so as to surround the conductor core wire 10 and then extruding the material constituting the outer skin layer 30 so as to surround the insulating coating 20 covering the conductor core wire 10. can. Alternatively, the resin material forming the insulating coating 20 and the material forming the skin layer 30 can be collectively extruded so as to surround the conductor core wire 10 .

The effect of mixing the mixture 32 with the base material 31 in the skin layer 30 will be described below. When the electric wire 1 is actually used, the temperature of the conductor core wire 10 rises due to Joule heat generated in the conductor core wire 10 when the electric wire 1 is energized. In the electric wire 1 , the conductor core wire 10 is covered with the insulating coating 20 and the outer skin layer 30 in multiple layers, so that the heat generated in the conductor core wire 10 is difficult to dissipate to the outside of the electric wire 1 . Therefore, as the temperature of the conductor core wire 10 rises, the temperature of the entire electric wire 1 also rises, and there is a possibility that the insulation coating 20 and the outer skin layer 30 will deteriorate due to heat.

In this respect, in the electric wire 1 according to the first embodiment, the outer skin layer 30 surrounding the insulating coating 20 covering the conductor core wire 10 is mixed with the base material 31 and has better heat conductivity than the base material 31. and mixture 32. Therefore, heat can be efficiently transferred from the insulating coating 20 to the outer layer 30 and heat can be released from the outer layer 30 to the outside of the electric wire 1 more efficiently than when the outer layer 30 is composed only of the base material 31 . In other words, the overall heat dissipation of the electric wire 1, which is a multi-layer structure including the insulating coating 20 and the outer skin layer 30, can be improved. Furthermore, in the electric wire 1 according to the first embodiment, compared to the case where a heat absorbing material (for example, a metal case or the like) is provided outside the outer skin layer 30, the workability and the wiring route when wiring the electric wire 1 are improved. Excellent freedom of

<Second embodiment>
In the above-described first embodiment, as shown in FIG. 1, the outer peripheral surface of the insulating coating 20 is configured as a smooth cylindrical outer peripheral surface, and the inner peripheral surface of the outer skin layer 30 is configured as a smooth cylindrical inner peripheral surface. ing. On the other hand, as in the second embodiment shown in FIG. 2, convex portions 20A projecting radially outward of the electric wire 1 and extending in the extending direction of the electric wire 1 are provided at a plurality of locations in the circumferential direction of the outer peripheral surface of the insulating coating 20. is provided, and at a plurality of locations in the circumferential direction of the inner peripheral surface of the outer skin layer 30, corresponding to the plurality of protrusions 20A of the insulating coating 20, recesses radially outward of the wire 1 and in the extending direction of the wire 1 The outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 may have a concave-convex fitting structure in which the plurality of convex portions 20A and the plurality of concave portions 30A are fitted to each other. .

In the second embodiment shown in FIG. 2, the uneven fitting structure formed by the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 contributes to heat transfer between the insulating coating 20 and the outer skin layer 30. The size of the area to be covered (that is, the size of the surface area of the outer peripheral surface of the insulating coating 20 and the size of the surface area of the inner peripheral surface of the outer skin layer 30) when there is no concave-convex fitting structure (the first shown in FIG. 1) 1 embodiment) can be increased. As a result, heat transfer from the insulating coating 20 to the outer skin layer 30 can be performed more efficiently, so that the heat dissipation characteristics of the electric wire 1 can be further improved.

In the second embodiment shown in FIG. 2, as in the first embodiment, after the insulating coating 20 is extruded so as to surround the conductor core wire 10, the material constituting the outer skin layer 30 is applied to the insulation covering the conductor core wire 10. It may be manufactured by extrusion molding so as to surround the coating 20, or the resin material constituting the insulating coating 20 and the material constituting the outer skin layer 30 are collectively extruded so as to surround the conductor core wire 10. It may be manufactured by

In the second embodiment shown in FIG. 2, when the outer skin layer 30 is molded, the material forming the outer skin layer 30 enters between the plurality of protrusions 20A formed on the outer peripheral surface of the insulating coating 20 and solidifies. , a concave-convex fitting structure is formed. However, if the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30, which constitute the concave-convex fitting structure, are not completely in close contact with each other, there may be a gap between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30. A minute gap S may intervene (see FIG. 3). If air having poor heat conductivity exists in the minute gap S, the heat transfer from the insulating coating 20 to the outer skin layer 30 is hindered, and the heat dissipation characteristics of the electric wire 1 may deteriorate.

In order to deal with this point, in the second embodiment shown in FIG. 2, a minute gap S (between the convex portions 20A and A soft heat transfer body 40 having a better heat transfer property than air is arranged so as to fill part or the whole of the recess 30A (see FIG. 3). Grease, for example, is used as the soft heat conductor 40 . As a result, it is possible to prevent the heat transfer from the insulating coating 20 to the outer skin layer 30 from being hindered due to the presence of air in the minute gap S (including the gap between the convex portion 20A and the concave portion 30A).

When the soft heat conductor 40 is arranged, for example, the soft heat conductor 40 is simultaneously supplied between the insulation coating 20 and the skin layer 30 during the extrusion molding of the insulation coating 20 and the skin layer 30 described above. By doing so, the heat transfer body 40 can be arranged in the minute gap S. Alternatively, the insulating coating 20 is extruded so as to surround the conductor core wire 10, and then the outer peripheral surface of the insulating coating 20 is coated with a soft heat conductor 40 by a method such as a spray. may be extruded to surround the insulating coating 20 covering the conductor core wire 10 .

<Third Embodiment>
Furthermore, in the first and second embodiments described above, as shown in FIGS. ), a skin layer 30 is disposed. On the other hand, as in a third embodiment shown in FIG. The outer skin layer 30 may be arranged so as to be in close contact with the body.

<Other forms>
The present invention is not limited to the above-described embodiments, and various modifications can be adopted within the scope of the present invention. For example, the present invention is not limited to the above-described embodiments, and can be modified, improved, etc. as appropriate. In addition, the material, shape, size, number, location, etc. of each component in the above-described embodiment are arbitrary and not limited as long as the present invention can be achieved.

For example, in the electric wire 1 according to the first embodiment, the insulating coating 20 is not mixed with a heat conductive mixture such as the mixture 32 in the outer skin layer 30 . On the other hand, like the skin layer 30, the material forming the insulating coating 20 may also be mixed with a heat conductive mixture. As a result, heat can be more efficiently transferred from the conductor core wire 10 to the insulating coating 20, so that the overall heat dissipation of the electric wire 1, which is a multilayer structure, can be further improved. However, by mixing the mixture with the material that constitutes the insulating coating 20, the insulation properties of the insulating coating 20 may be reduced, and the mixture may be exposed to the inner peripheral surface of the insulating coating 20. There is a possibility that deterioration of the insulating coating 20 or the like may occur due to the occurrence of an electric discharge. Therefore, when maintaining the function of the insulating coating 20 is emphasized rather than further improving heat dissipation, the outer skin layer 30 is made of a resin material containing a mixture 32 having excellent heat transfer properties, as in the electric wire 1 according to the first embodiment. Moreover, it is preferable that the insulating coating 20 is made of a resin material that does not contain such a mixture.

Furthermore, in the above-described second embodiment, the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 have an uneven fitting structure, and the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 A soft heat transfer body 40 is arranged in the minute gap S of . On the other hand, if the adhesion between the outer peripheral surface of the insulating coating 20 and the inner peripheral surface of the outer skin layer 30 is sufficient from the viewpoint of heat dissipation, the soft heat conductor 40 does not have to be arranged in the gap.

Furthermore, in the second embodiment, the convex portion 20A extending in the extending direction of the electric wire 1 and the concave portion 30A extending in the extending direction of the electric wire 1 are fitted. On the other hand, a concave-convex fitting structure may be configured by fitting convex portions and concave portions having other shapes. For example, protrusions and recesses extending in the circumferential direction of the wire 1, protrusions and recesses extending spirally around the axis of the wire 1, and protrusions and recesses that are mountain-shaped or column-shaped protrusions, etc. A mating structure may be configured.

Furthermore, in the third embodiment, the outer peripheral surface of the insulating coating 20 covering each of the plurality of conductor core wires 10 is a smooth cylindrical outer peripheral surface. On the other hand, part or all of the outer peripheral surface of these insulating coatings 20 may be provided with protrusions as shown in FIG. That is, the features of the second embodiment and the features of the third embodiment may be combined.

Here, the characteristics of the electric wire 1 according to the present invention described above are summarized and listed briefly in [1] to [3] below.

[1]
a conductor core wire (10);
an insulating coating (20) arranged to surround the outer circumference of the conductor core wire (10);
An electric wire (1) comprising a skin layer (30) arranged to surround the outer periphery of the insulating coating (20),
The skin layer (30) is
Consists of a material containing a base material (31) and a mixture (32) having better heat transfer properties than the base material (31) and mixed with the base material (31),
Electric wire (1).

According to the electric wire having the configuration of [1] above, the outer skin layer surrounding the insulating coating covering the conductor core wire is made of a material containing a base material and a mixture that is more excellent in heat transfer than the base material and is mixed with the base material. Configured. Therefore, heat can be efficiently transferred from the insulating coating to the outer layer and heat can be released from the outer layer to the outside of the wire more efficiently than when the outer layer is composed of only the base material. In other words, it is possible to improve the overall heat dissipation of the multilayer structure including the insulating coating and the outer skin layer. Therefore, the electric wire of this configuration is excellent in heat radiation characteristics to the outside of the heat generated in the conductor core wire. Furthermore, as another effect, the electric wire having the above configuration has the advantage of workability and ease of wiring when wiring the electric wire, compared to the case where a heat absorbing material (for example, a metal case, etc.) is provided outside the outer skin layer. Excellent flexibility.

[2]
In the electric wire (1) according to [1] above,
The outer peripheral surface of the insulating coating (20) and the inner peripheral surface of the outer skin layer (30) are
In the radial direction of the electric wire (1), one has a convex portion (20A) that protrudes toward the other, and the other has a concave-convex fitting structure that has a concave portion (30A) that is depressed with respect to the other.
Electric wire (1).

According to the electric wire having the configuration [2] above, the area that contributes to heat transfer between the insulating coating and the outer layer due to the concave-convex fitting structure formed by the outer peripheral surface of the insulating coating and the inner peripheral surface of the outer layer. The size (that is, the surface area of the outer peripheral surface of the insulating coating and the surface area of the inner peripheral surface of the outer skin layer) can be made larger than when there is no concave-convex fitting structure. As a result, heat can be transferred from the insulating coating to the outer skin layer more efficiently, so that the heat dissipation characteristics of the electric wire can be further improved. In addition, such a concave-convex fitting structure can be configured, for example, by collectively extruding the insulating coating and the skin layer so as to surround the conductor core wire.

[3]
The electric wire (1) according to [2] above,
Further comprising a soft heat conductor (40) arranged to fill at least part of the gap (S) between the convex portion (20A) and the concave portion (30A),
Electric wire (1).

According to the electric wire having the configuration [3], the soft heat transfer body is arranged so as to fill at least a part of the gap between the convex portion and the concave portion that constitute the concave-convex fitting structure. As a result, it is possible to prevent the heat transfer from the insulating coating to the outer skin layer from being hindered due to the air being sandwiched between the protrusions and the recesses. Therefore, heat can be transferred from the insulating coating to the outer skin layer more efficiently, so that the heat dissipation characteristics of the electric wire can be further improved. In addition, for example, by supplying a soft heat transfer body between the insulation coating and the skin layer during the extrusion molding of the insulation coating and the skin layer, the heat transfer body can be arranged in the gap.

REFERENCE SIGNS LIST 1 electric wire 10 conductor core wire 20 insulation coating 30 skin layer 31 base material 32 mixture 40 heat conductor S gap

Claims (3)

a conductor core wire;
an insulating coating arranged to surround the outer circumference of the conductor core wire;
An electric wire comprising a skin layer arranged to surround the outer periphery of the insulating coating,
The skin layer is
Consists of a material containing a base material and a mixture that is mixed with the base material and has better heat conductivity than the base material,
Electrical wire. In the electric wire according to claim 1,
The outer peripheral surface of the insulating coating and the inner peripheral surface of the outer skin layer are
In the radial direction of the wire, one has a convex portion that protrudes toward the other, and the other has a concave-convex fitting structure that has a concave portion that is depressed with respect to the other.
Electrical wire. The electric wire according to claim 2,
further comprising a soft heat conductor arranged to fill at least part of the gap between the convex portion and the concave portion;
Electrical wire.

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