JP2018073830A - Insulated wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve tear and wear resistance of an insulated wire in which a rubber material with poor tear and wear resistance is used for an insulating layer, and also reduce the influence of external force on a conductor.MEANS FOR SOLVING THE PROBLEM: A plurality of insulating layers formed of rubber materials are provided, and the properties of the rubber materials are changed for each layer.SELECTED DRAWING: Figure 1

Description

The present invention relates to an insulated wire, and is particularly suitable for a high-voltage power cable used for automobiles, electrical and electronic equipment, and the like.

The electrical disconnection wire used for vehicles such as automobiles is required to have various characteristics such as mechanical characteristics, flame retardancy, heat resistance, and cold resistance.

Recently, electric vehicles using electric motor drive and hybrid vehicles using both motor drive and conventional gasoline engine drive have appeared. An automobile using such a motor drive needs to supply a high voltage and a large current for the motor drive. In general, an insulated wire that supplies a high voltage and a large current is used with a large conductor cross-sectional area, and high insulation is also required as the voltage and current increase.

On the other hand, there is a tendency for the space for the insulated wires to be reduced in order to secure the interior space and improve the design. In order to cope with this, the insulated wires can be arranged with a short length and a small bending radius. Is also required.

  That is, it is necessary to bend a thick and short insulated wire with a small bending radius, and in order to cope with this, it is necessary to use an insulated wire having excellent flexibility. In order to obtain an insulated wire excellent in flexibility, it is necessary to make at least one of the conductor and the insulating layer constituting the insulated wire, preferably both flexible.

As a method for making an insulating layer covering a conductor flexible, a method using a rubber material as a material constituting the insulating layer is known. Examples of the rubber material used for the insulating layer include fluorine rubber, fluorosilicone rubber, acrylic rubber, EPDM, and silicone rubber.
Among these materials, when a preferable material is selected from the viewpoints of flexibility, insulation, heat resistance, and cold resistance, silicone rubber is a preferable material, but when silicone rubber is used for an automobile wire, The present situation is not necessarily a preferable choice because of the following difficulties.

Silicone rubber is generally low in mechanical strength, and once scratched, it is easy to tear, and it is difficult to have low wear resistance, and there is a concern about poor insulation due to damage to the insulator.

In addition, silicone rubber is inferior in oil resistance and acid resistance. Swelling due to adhesion of gasoline used in automobiles, ATF (automatic transmission oil), engine oil, etc. There are also concerns about hydrolysis due to.

As a method of increasing the mechanical strength, there is a method of adding hollow spherical titanium oxide or flaky titanium oxide to a silicone resin (Patent Document 1). However, even if the mechanical strength is increased, once the silicone resin layer is scratched, the silicone resin layer is easily torn, and there remains a concern about insulation failure due to damage.

As a method for improving oil resistance, a method of coating a silicone rubber with a material having oil resistance, such as coating the surface of silicone rubber with a thin film of polyurethane resin (Patent Document 2) is known. However, a material having oil resistance has physical properties such as flexibility and heat resistance that are not necessarily equivalent to those of silicone rubber, and there is a problem that the use environment is limited.

As a method for increasing acid resistance (battery liquid resistance), a method of providing a thin film layer containing polytetrafluoroethylene on the surface of a silicone rubber used as a coating for an insulated wire (Patent Document 3) is known. There is a problem that the thin film layer cannot follow the deformation of the insulated wire, and the thin film layer is peeled off and cracked to expose the silicone rubber, resulting in a decrease in battery fluid resistance.

In addition, the insulated wire using silicone rubber for the insulation layer is flexible because the silicone rubber is flexible, so if a momentary strong impact is generated on the insulated wire, the influence of the external force also affects the conductor, There is also a risk of damage to the insulating layer due to broken conductors.

  Not only silicone rubber but also rubber materials that are easy to tear, rubber materials with low wear resistance, and rubber materials with high flexibility are used for the insulation layer. Concerned.

JP 2004-91642 A JP-A-8-118417 Japanese Patent Application Laid-Open No. 2006-149292

The object of the present invention is to improve the tear resistance and wear resistance even when a rubber material that is easily torn or a rubber material having low wear resistance is used for the insulating layer, and to suppress the influence of the impact on the conductor. It is to provide electric wires.

As a result of earnestly examining the structure of the insulated wire, the present inventor has provided a plurality of insulating layers made of a rubber material, and has changed the characteristics of the rubber material depending on the layer, thereby solving the conventional problems.

The present invention is an insulated wire in which an insulating layer is coated around a conductor, and the insulating layer is formed by laminating a plurality of layers, and at least two of the insulating layers are formed of a rubber material. It is characterized by being.

A more preferred configuration of the present invention is characterized in that at least one of the layers formed of the rubber material has a hardness different from that of the other layers formed of the rubber material.

Another preferred configuration of the present invention is characterized in that a filler (filler) is contained in at least one of the layers formed of a rubber material.

In the insulated wire of the present invention, the excellent effects described below can be expected.

(1) By constituting the insulating layer with a plurality of rubber material layers, it is possible to improve tear resistance and wear resistance, which were insufficient with only a single rubber material layer.

(2) By providing a difference in hardness between the plurality of rubber material layers, both the resilience and shock absorption of the insulating layer can be achieved.

(3) By containing a filler in the rubber material layer, oil resistance and acid resistance can be imparted to the insulating layer.

In the basic structure of the present invention, there are two insulating layers. In the example of the basic structure of the present invention, there are three insulating layers. It is a conventional insulated wire structure

Hereinafter, the basic configuration of the present invention will be described with reference to the accompanying drawings.
1 and 2, 1 is an insulated wire of the present invention, 2 is a conductor, and 3 is an insulating layer.
In FIG. 1, the insulating layer 3 has a two-layer structure of a first insulating layer 3a and a second insulating layer 3b.
In FIG. 2, the insulating layer 3 has a three-layer structure of a first insulating layer 3a, a second insulating layer 3b, and a third insulating layer 3c.
In the present invention, the insulating layer 3 is not limited to the two-layer structure and the three-layer structure, and may have a four-layer structure or more as necessary.

What is characteristic of the present invention is that the insulating layer 3 covered around the conductor 2 is formed by laminating a plurality of layers, and at least two of the insulating layers 3 are made of a rubber material. It is to be a layer.

That is, in FIG. 1, both the first insulating layer 3a and the second insulating layer 3b are formed of a rubber material.
In FIG. 2, it is only necessary that any two of the first to third insulating layers 3a to 3c are made of a rubber material, and the remaining one layer is made of a rubber material. It may be formed by.

By forming the insulating layer 3 in a laminated structure and forming at least two layers of a rubber material, tear resistance and wear resistance are improved as compared with an insulated wire in which the insulating layer 3 is formed of only one rubber material. The

When the insulating layer 3 is an insulated wire 1 ′ having only one rubber material as shown in FIG. 3, once the insulating layer 3 is cut and scratched, it is torn when further stress is applied to the insulating layer 3. (Scratches) propagate in the thickness direction of the insulating layer 3, and the conductor 2 is easily exposed to make it impossible to maintain insulation.
On the other hand, in the case of the insulated wire 1 shown in FIG. 1 in which the insulating layer 3 has a two-layer structure, even if the second insulating layer 3b is damaged, the propagation of tearing is the same as that of the second insulating layer 3b. Since it stops at the interface of the first insulating layer 3a, the conductor 2 is not exposed and the insulation is maintained. Even when the second insulating layer 3b has been torn, the second insulating layer 3b itself is present around the first insulating layer 3a, so that the first insulating layer 3a is protected by the second insulating layer 3b. Damage to the 1 insulating layer 3a can be suppressed. The same is true for wear resistance.

In the case of the insulated wire 1 in which the insulating layer 3 has a three-layer structure shown in FIG. 2, higher tear resistance and wear resistance can be obtained by increasing the number of layers.
Further, by configuring the third insulating layer 3c, which is the outermost layer, of a rubber material having a high tear resistance, by obtaining a higher tear resistance, or by configuring the third insulating layer 3c with a fluoro rubber, It is also possible to obtain oil resistance and acid resistance.

The rubber material used for the insulating layer 3 of the present invention may be the same type of rubber material for each layer, or may be used by changing physical properties, materials, etc. of the rubber material depending on the layer.
In the present invention, it is possible to further change to a preferred mode by making a difference in the characteristics of the rubber material of at least two layers constituting the insulating layer 3.

Hardness exists as one of the physical properties of the rubber material. In the present invention, the hardness of the rubber material of at least two layers constituting the insulating layer 3 may be equal or different.
From the viewpoint of increasing the durability of the insulated wire 1, an aspect in which at least one of the rubber material layers constituting the insulating layer 3 has a hardness different from that of the other rubber material layers, that is, a low hardness rubber material layer and a high hardness An embodiment in which the insulating layer 3 is formed by combining the rubber material layers can be preferably used.

Generally, a rubber material with high hardness has high impact resilience. By constituting the insulating layer 3 with a material having high impact resilience, it is possible to suppress deformation of the insulating layer 3 when the insulated wire 1 receives an impact. On the other hand, when a material having high impact resilience is used for the insulating layer 3, there is a problem that the influence of the impact is easily transmitted to the conductor 2 and easily leads to conductor breakage.

Generally, a rubber material having a low hardness is excellent in shock absorption. By configuring the insulating layer 3 with a material excellent in shock absorption, it is difficult for the influence when the insulated wire 1 receives an impact to be transmitted to the conductor 2, and the conductor deformation can be suppressed. On the other hand, when a material having high shock absorption is used for the insulating layer 3, there is a problem that the insulating layer 3 itself is deformed.

By forming the insulating layer 3 by combining rubber material layers having different hardnesses, the deformation suppressing effect of the insulating layer 3 and the damage suppressing effect of the conductor 2 can be compatible.

Methods for changing the hardness of the rubber material include methods such as changing the amount of filler added, changing the molecular weight of the constituent molecules, changing the crosslinking density, and changing the type of rubber material.

In the present invention, a method of increasing the hardness of the rubber material by increasing the amount of filler added can be particularly preferably used.

When the oil resistance and acid resistance of the rubber material are poor, by adding a filler, oil resistance and acid resistance are added to the rubber material as the hardness increases. By using a rubber material layer containing a filler as a part of the insulating layer 3, oil resistance and acid resistance of the insulated wire 1 are improved.

Suitable types of filler include silica, titanium oxide, magnesium oxide, magnesium hydroxide, talc, clay, cerium oxide, boron nitride, glass beads, alumina, iron oxide and the like.

Particularly in the present invention, scaly fillers can be suitably used. The scaly filler has a shape in which the filler particles have a certain length and width and, as a result, a certain area.

By using a scale-like filler having a certain area, the area functions as a shielding wall against oil and acid, and the oil resistance and acid resistance of the rubber material layer to which the filler is added can be enhanced.

It is preferable that the scale-like filler has its longitudinal direction oriented along the length direction of the insulated wire 1. Since the longitudinal direction of the scale-like filler is oriented along the length direction of the insulated wire, the amount of area that functions as a shielding wall against oil and acid increases when the lengthwise cross section of the insulated wire is viewed Furthermore, oil resistance and acid resistance are improved.

  In order to achieve this orientation state, an insulating layer containing a scale-like filler may be formed using a general extrusion molding method as a method for providing a coating layer for an insulated wire. In the process of extruding the insulating layer, the longitudinal direction of the scaly filler is oriented along the length direction of the insulated wire 1.

In the present invention, it is desirable that the layer made of the rubber material constituting the insulating layer 3 is adjacent to the layer made of the rubber material, and the layers are integrated. Since the layers are integrated, the gap between the layers is reduced, and corona discharge in the gap is suppressed. As a result, the corona resistance of the insulated wire is improved.
Even if the layers formed of rubber material are integrated, or if the two layers that were originally laminated are integrated, the function as an interface between the layers can be achieved even if the gap between the layers is reduced. It contributes to the improvement of tear resistance and wear resistance.

A specific method for integrating the layers includes a method of chemically bonding two rubber material layers by a method such as co-crosslinking or a method of chemically adhering them.
As an example, after the rubber material layer is extruded on the conductor 2, another rubber material layer is extruded while the extruded rubber material is not thermally cured, and then heat treatment is performed. There is a method in which two rubber material layers are co-crosslinked and integrated.

One rubber material that can be particularly preferably used in the present invention is silicone rubber. Silicone rubber is generally preferred in terms of flexibility, insulation, heat resistance, and cold resistance, but is inferior in tear resistance, wear resistance, oil resistance, and acid resistance.
When silicone rubber is selected as the rubber material used in the present invention, the disadvantages of silicone rubber can be improved by the present invention. Therefore, an insulated wire using a silicone rubber insulating layer is used even in environments where it has been difficult to use in the past. it can.

Another rubber material that can be particularly preferably used in the present invention is fluororubber.
Fluoro rubber is generally preferable from the viewpoint of tear resistance, abrasion resistance, oil resistance, acid resistance, chemical resistance, and heat resistance, but is inferior in cold resistance.
When fluorine rubber is used as the rubber material used in the present invention, the disadvantage of silicone rubber can be compensated by using it together with silicone rubber.

  Examples of the present invention and comparative examples are shown below.

[Examples 1 and 2]
As Example 1 and 2, the insulated wire 1 which has the 1st insulating layer 3a and the 2nd insulating layer 3b is created.
Prepare the child stranded conductor of annealed copper wire was combined 32-ply diameter 0.32 mm, 19 present the child stranded conductors, twisted concentrically twisted structure, to form the cross-sectional area 50 mm ² corresponding conductors 2.
Next, using an extrusion molding machine, the outer periphery of the conductor 2 was coated with a rubber material to be the first insulating layer 3a, and then heat treatment according to the rubber material was performed to provide the first insulating layer 3a.
Furthermore, the outer periphery of the first insulating layer 3a is covered with a rubber material to be the second insulating layer 3b, heat-treated to provide the second insulating layer 3b, and the insulated wire having the first insulating layer 3a and the second insulating layer 3b 1 was obtained.

Specific configurations of Examples 1 and 2 are shown in Table 1 below. The hardness is durometer hardness A. Unless otherwise specified, the same material having the same physical properties was used for the insulating layers having the same material and hardness.

[Comparative Examples 1 and 2]
Insulated wires 1 ′ in which only one insulating layer 3 made of a rubber material was coated on the same conductor 2 as in Examples 1 and 2 were prepared as Comparative Examples 1 and 2.

Specific configurations of Comparative Examples 1 and 2 are shown in Table 1 below. In Examples 1 and 2, the insulating layer 3 has a two-layer structure, while in Comparative Examples 1 and 2, the insulating layer 3 has a single-layer structure with a thickness of 1.5 mm.

Each insulated wire created as described above was subjected to the tests described below, and various performances were evaluated and compared.

[Abrasion resistance test]
The test was conducted in accordance with the Japan Automobile Engineers Association standard “JASO D618”.
A specific method is to cut out an insulated wire to a length of 1 m to make a test piece, and along the length direction of the insulated wire, a 0.63 N pressing force is generated against the insulating layer of the test piece. The endless wear tape was brought into contact with the central portion in the length direction, and the tape was moved at a speed of 1500 mm / min.
A tape conforming to garnet P150 defined in JIS R6251 was used, and a conductive portion for conductor exposure detection having a width of 10 mm was provided at intervals of 150 mm.
The moving distance of the tape until the conductive part for conductor exposure detection contacted the conductor 2 was measured and evaluated as follows.

◎: Travel distance 3000 mm or more ○: Travel distance 2000 to 3000 mm
Δ: Movement distance 1000 to 2000 mm
×: Movement distance less than 1000 mm

[Tear resistance test]
Only the insulating layer 3 was collected from the insulated wire into a strip shape having a width of 5 mm and a length of 100 mm to obtain a test piece.
A scratch having a depth of 0.3 mm is provided on the surface of the central portion of the test piece in the direction perpendicular to the length direction using a blade, and both ends of the test piece are fixed with a chuck of a tensile tester, and 200 mm A tensile test was conducted at a tensile speed of / min.
The value indicated by the tensile tester when the insulating layer 3 was completely broken was regarded as the tear strength of the insulating layer 3 and evaluated as follows.

A: Tear strength 50 N / mm or more B: Tear strength 35-50 N / mm
Δ: Tear strength 20 to 35 N / mm
×: Tear strength less than 20 N / mm

[Impact resistance test]
The insulated wire was cut into a length of 50 mm to obtain a test piece.
A weight of 500 g was dropped from a height of 2 m to the center of the insulated wire in the length direction, and the surface state of the insulating layer 3 was observed and evaluated as follows.

◎: No scratch or dent ○: No scratch, dent △: Both scratch or dent ×: Conductor exposure

[Oil resistance test]
The test was conducted in accordance with the Japan Automobile Engineers Association standard “JASO D618”.
A specific method is to cut an insulated wire into 600 mm to make a test piece, soak the test piece in gasoline specified in ISO1817 at 23 ± 5 ° C. for 20 hours, take out, wipe the surface, and dry at room temperature for 30 minutes. The outer diameter of the insulated wire was measured within 5 minutes, the outer diameter change rate was determined based on the formula (1), and evaluated as follows.

(Formula 1) Outer diameter change rate = (outer diameter after immersion−outer diameter before immersion) / (outer diameter before immersion) × 100 (%)

○: Outer diameter change rate 15% or less ×: Outer diameter change rate more than 15%

[Battery fluid resistance test]
The test was conducted in accordance with the Japan Automobile Engineers Association standard “JASO D618”.
Specifically, the insulated wire is cut to 600 mm to form a test piece, and battery solution (25% sulfuric acid solution, specific gravity 1.26) is dropped at four locations with a 100 mm interval in the length direction.
Thereafter, the test piece is placed in a test furnace set at 90 ° C. and left for 8 hours.
After 8 hours, the test piece is taken out from the test furnace, the battery solution is dropped on the same place, put into the test furnace set at 90 ° C., and left for 16 hours.
This procedure is defined as one cycle and a total of two cycles are performed.
Then, after the surface state was confirmed by bending the battery droplet lower part of the test piece returned to room temperature to a radius of 50 mm, a withstand voltage test of the insulated wire was performed at 1 kV and evaluated as follows.

◎: Insulation layer surface without cracking, withstanding voltage test passed ○: Insulating layer surface with cracking, but withstanding voltage test passed ×: Insulating layer surface cracks markedly exposed conductor, withstand voltage test failed

The test results are shown in Table 1.

In Examples 1 and 2, the wear resistance, tear resistance, oil resistance, and battery liquid resistance were remarkably improved as compared with Comparative Example 1.
In Examples 1 and 2, since the fluororubber having excellent wear resistance, tear resistance, oil resistance, and battery liquid resistance is used in combination, the improvement of each property is affected by the material used, but the second insulating layer Even if damage occurs in 3b, it can be said that the insulating property of the insulated wire 1 is maintained by the first insulating layer 3a and that it can be used without any problem in actual use.

In Examples 1 and 2, compared with Comparative Example 2, although the wear resistance was reduced, the tear resistance was remarkably improved. Since the decrease in wear resistance is a decrease in a range where there is no problem in practical use, when compared with Comparative Example 2, Examples 1 and 2 suppress the damage of insulating layer 3 due to scratches by improving the tear resistance. It can be said that it was the aspect which did.

[Examples 3 and 4]
As Example 3 and 4, the insulated wire 1 which has the 1st insulating layer 3a, the 2nd insulating layer 3b, and the 3rd insulating layer 3c is created.
After providing the first insulating layer 3a and the second insulating layer 3b on the outer periphery of the conductor 2 as in Examples 1 and 2, the outer periphery of the second insulating layer 3b is covered with a rubber material that becomes the third insulating layer 3c, Heat treatment was performed to provide the third insulating layer 3c, and the insulated wire 1 having the first insulating layer 3a, the second insulating layer 3b, and the third insulating layer 3c was obtained.

Specific configurations of Examples 3 and 4 are shown in Table 2 below. The conductor 2 is the same as in Examples 1 and 2.

[Comparative Examples 3 and 4]
Insulated wires 1 ′ in which only one insulating layer 3 made of a rubber material was coated on the same conductor 2 as in Examples 1 and 2 were prepared as Comparative Examples 3 and 4.

Specific configurations of Comparative Examples 3 and 4 are shown in Table 2 below. In Examples 3 and 4, the insulating layer 3 has a three-layer structure, while in Comparative Examples 3 and 4, the insulating layer 3 has a single-layer structure with a thickness of 1.5 mm.

Table 2 shows the results of various tests described above for Examples 3 and 4 and Comparative Examples 3 and 4.

In Examples 3 and 4, the wear resistance and tear resistance were remarkably improved as compared with Comparative Examples 3 and 4.
In Examples 3 and 4, since the tear-resistant silicone rubber is used for the third insulating layer 3c, the improvement of the tear resistance is affected by the material used, but the third insulating layer 3c is damaged. In addition, it can be said that the insulating effect of the insulated wire 1 is maintained by the first insulating layer 3a and the second insulating layer 3b and can be used without any problem in actual use.

Regarding the impact resistance, no significant difference was observed between the examples 3 and 4 and the comparative examples 3 and 4 in the evaluation, but the insulating layers 3 were formed by combining the silicone rubbers having different hardness in the examples 3 and 4. The impact resistance is considered to be improved by the interaction between the impact resilience of the high hardness silicone rubber and the impact absorption of the low hardness rubber. It is thought that a difference in impact resistance sometimes appears.

Since Examples 3 and 4 are not intended to improve oil resistance and battery liquid resistance, these two points are not significantly different from the comparative example. Examples 5 to 7 are shown as intended to improve oil resistance and battery liquid resistance.

[Examples 5 to 7]
Examples 5-7 are the aspects which added the filler to a part of insulating layer. Specific configurations of Examples 5 to 7 are shown in Table 3 below. The conductor 2 is the same as in Examples 1 and 2.

The filler used in Examples 5 to 7 is as follows.

・ Filler: Spherical titanium oxide ・ Scale-like filler: Scale-like iron oxide

[Comparative Examples 5 and 6]
Specific configurations of Comparative Examples 5 and 6 are shown in Table 3 below. The conductor 2 is the same as in Examples 1 and 2. Examples 5 to 7 have a three-layer structure in which the insulating layer 3 has a thickness of 0.5 mm. Among them, a filler is added to one layer, while Comparative Examples 5 and 6 have a thickness of 1.5 mm. It has a structure in which a filler is added to a single insulating layer.

Table 3 shows the results of various tests described above for Examples 5 to 7 and Comparative Examples 5 and 6.

In Example 5, although the oil resistance was insufficient, it was confirmed that the battery liquid resistance was improved by adding a filler to the third insulating layer 3c.

In Example 6, the oil resistance improvement effect could be confirmed as the amount of filler added increased.

In Example 7, the amount of filler added is the same as that in Example 6, but the effect of improving oil resistance that was insufficient in Example 5 can be confirmed by using a scale-like filler having a certain area. It was.

Comparative Examples 5 and 6 also confirmed the effect of improving oil resistance and battery liquid resistance by the addition of filler, but since the insulating layer 3 is a single layer, the tear resistance was inferior to those of Examples 5 to 7, in particular. became.

Moreover, compared with Comparative Examples 5 and 6, Examples 5-7 had improved impact resistance, and the impact resistance improvement effect by combining silicone rubber layers having different hardness could be confirmed.

Examples 5-7 are the aspects which added the filler to the 3rd insulating layer 3c, However, The insulating layer which adds a filler is not limited to the 3rd insulating layer 3c, It adds to the 1st, 2nd insulating layer You may do it.

[Examples 8 and 9]
As Example 8 and 9, the insulated wire 1 which used the fluoro rubber for a part of 1st insulating layer 3a-3rd insulating layer 3c is shown. Specific configurations of Examples 8 and 9 are shown in Table 4 below. The conductor 2 is the same as in Examples 1 and 2.

[Comparative Example 2]
The comparative example 2 mentioned above. As a comparative example with respect to Examples 8 and 9, it is shown again in Table 4. Examples 6 and 7 have a three-layer structure in which the insulating layer 3 has a thickness of 0.5 mm, of which one layer uses fluororubber, whereas in Comparative Example 2, the insulating layer 3 has a thickness. It has a single-layer structure made of 1.5 mm fluororubber.

Table 4 shows the results of various tests described above for Examples 8 and 9 and Comparative Example 2.

In Examples 8 and 9, the fluororubber layer excellent in oil resistance and chemical resistance was present, so that the effect of improving oil resistance and battery liquid resistance could be confirmed.

Since Comparative Example 2 also uses fluororubber for the insulating layer, the oil resistance and battery liquid resistance are excellent, but since the insulating layer 3 is a single layer, the tear resistance is higher than in Examples 8 and 9. The result was inferior.

Examples 1, 2, 8, and 9 are embodiments in which the insulating layer 3 is formed of silicone rubber and fluororubber. In the present invention, in addition to fluororubber, EPDM rubber, Various rubber materials such as acrylic rubber may be appropriately selected and used.

The above example is merely an example of the present invention, and various modifications and applications are possible as long as they are within the scope of the present invention.
The present invention is particularly suitable for high-voltage power cables used in automobiles, electrical and electronic equipment, etc., but the application is not limited to these, and the present invention is applied to other cables and insulated wires. It may be applied.

1, 1 ′ insulated wire 2 conductor 3 insulating layer 3a first insulating layer 3b second insulating layer 3c third insulating layer

Claims (8)

An insulated wire in which an insulating layer is coated around a conductor, and the insulating layer is formed by laminating a plurality of layers, and at least two of the insulating layers are layers formed of a rubber material. An insulated wire characterized by that. The insulated wire according to claim 1, wherein at least one of the layers formed of the rubber material has a hardness different from that of the other layers formed of the rubber material. The insulated wire according to claim 1 or 2, wherein a filler is contained in at least one of the layers formed of the rubber material. The insulated wire according to claim 3, wherein the filler has a scaly shape. The insulated wire according to claim 4, wherein a longitudinal direction of the scale-like filler is oriented in a length direction of the insulated wire. The insulated wire according to any one of claims 1 to 5, wherein the layers formed of the rubber material are adjacent to each other, and the layers formed of the rubber material are integrated. . The insulated wire according to any one of claims 1 to 6, wherein at least one of the layers formed of the rubber material is formed of silicone rubber. The insulated wire according to claim 7, wherein at least one of the layers formed of the rubber material is formed of a material other than silicone rubber.

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