JP2010061922A - Insulation wire, electric coil, and electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation wire with a high partial discharge starting voltage which is manufactured without using a varnish to be manufactured by a complicated process, an electric coil consisting of this insulation wire, and an electric motor using this electric coil. <P>SOLUTION: The insulation wire includes a conductor, an insulation layer to insulate the conductor, and an antistatic layer to cover the insulation layer. The antistatic layer includes a polyether-ester amide resin as a main component and the surface resistance of the antistatic layer is 10<SP>9</SP>to 10<SP>12</SP>Ω. There are provided the electric coil consists of this insulation wire and an electric motor using the electric coil. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an insulated wire used as a winding of a motor coil, an electric coil using the insulated wire, and a motor using the electric coil.

  When a high voltage is applied to a coil of a rotating electrical machine such as a motor, partial discharge (corona discharge) is likely to occur on the surface of the insulating film of the insulated wire that is the winding of the coil. Due to the occurrence of partial discharge, local temperature rise, ozone and ions are likely to be generated. As a result, the insulating film is deteriorated, resulting in a problem that the life of the insulated wire and thus the motor is shortened.

  Therefore, in order to suppress the partial discharge, an insulated wire having a high partial discharge start voltage is required. In Patent Document 1, a heat sealing resin is applied and baked on the outer layer of the insulating layer covering the conductor, A method of heat-sealing after winding work has been proposed. If there are minute voids in the insulating film of the insulated wire or between the insulated wires, the electric field concentrates on the portion and partial discharge is likely to occur. However, according to the method described in Patent Document 1, the insulated wire is thermally fused. The gaps between them can be filled, and the partial discharge start voltage can be improved. However, this method has a problem that a heat fusion process after the winding work is required.

  Patent Document 2 discloses an insulated wire having a conductive layer made of a polyimide resin varnish containing a conductive oxide such as iron trioxide, talc, or silica on a conductor. An insulated wire is proposed in which a conductive layer made of an oily enamel mixed with carbon black as a conductive filler and having a surface resistance of 1 kΩ to 1 MΩ is formed on the outer layer of a polyamideimide resin covering the conductor. . By such a conductive layer, the electrostatic potential gradient generated on the surface of the insulating film becomes gentle, electric field concentration can be prevented, and the partial discharge start voltage can be improved.

  However, in the method of Patent Document 2, since the specific gravity of the conductive oxide is large, the dispersibility of the conductive oxide in the conductive layer is reduced, and the conductive oxide aggregates in the insulating layer, thereby There was a problem that the physical characteristics (flexibility) deteriorated. Further, in the method of Patent Document 3, since the surface resistance of the conductive layer is set to 1 kΩ to 1 MΩ, there is a problem that the leakage current at the time of AC energization increases, the surface of the insulated wire generates heat, and thus deteriorates. .

Therefore, in Patent Document 4, a semiconductive layer made of a mixture of resin and carbon black and having a surface resistance of 10 ⁸ Ω or more and less than 10 ¹² Ω is formed on the outer layer of the insulating layer formed on the conductor. Formed insulated wires have been proposed. In this insulated wire, the partial discharge start voltage can be improved, the leakage current is small, deterioration due to heat generation on the surface is suppressed, and the mechanical properties (flexibility) of the insulated wire can be improved. .
JP-A-10-261321 JP-A-10-41122 JP 2004-254457 A JP 2007-294312 A

  The semiconductive layer of the insulated wire of Patent Document 4 is formed by a method in which a varnish containing a mixture of resin and carbon black is applied on the insulating layer and sintered. However, this varnish needs to be produced by dissolving the resin in an organic solvent and then mixing and kneading the carbon black, and the production process is complicated, resulting in high processing costs. Further, when the mixing of the resin and carbon black is insufficient, the dispersion of the carbon black becomes insufficient, which causes a decrease in the mechanical properties (flexibility) of the insulated wire.

  The present invention solves these problems of the prior art, and is an insulated wire having a high partial discharge starting voltage, which can be produced without using a varnish that requires a complicated production process. It is an issue to provide.

As a result of intensive studies to solve the above problems, the present inventor has a polyether ester amide resin as a main component on the surface of the insulated wire, that is, the insulating layer covering the conductor, and a surface resistance of 10 ⁹ Ω to It has been found that the above-mentioned problems can be achieved by providing an antistatic layer in the range of 10 ¹² Ω, and the present invention has been completed.

The present invention, as claim 1 thereof,
An insulated wire having a conductor, an insulating layer covering the conductor, and an antistatic layer covering the insulating layer,
The antistatic layer comprises a polyether ester amide resin as a main component, and the surface resistance of the antistatic layer is 10 ⁹ Ω or more and 10 ¹² Ω or less.

  Polyetheresteramide, which is a material for forming the antistatic layer, is an ester bond between a polyamide component having carboxyl groups at both ends and a polyether component that is a polymer obtained by ether-bonding bisphenols. It is known that the resulting block copolymer imparts excellent antistatic properties as an antistatic agent for thermoplastic resins. For example, Japanese Patent Application Laid-Open No. 7-10998 discloses a polyamide having a number average molecular weight of 500 to 5,000 having carboxyl groups at both ends and an ethylene oxide adduct of bisphenols having a number average molecular weight of 1,600 to 3,000. Polyether ester amide having a relative viscosity of 0.5 to 4.0 (0.5 wt% m-cresol solution, 25 ° C.) is disclosed and used as an antistatic agent for polystyrene, polymethyl methacrylate and the like. It is described.

In the present invention, the polyether ester amide resin disclosed in Japanese Patent Application Laid-Open No. 7-10989 can also be used in the present invention when the surface resistance of the antistatic layer satisfies the condition of 10 ⁹ Ω to 10 ¹² Ω. It can be used as a material for forming a layer. That is, the molecular weight, the type of monomer that is the raw material of the resin, the ratio of the polyamide component to the polyether component, etc. can be appropriately selected according to the heat resistance and mechanical properties required for the antistatic layer, There is no particular limitation as long as the condition that the resistance is 10 ⁹ Ω to 10 ¹² Ω is satisfied and the gist of the present invention is not impaired.

The antistatic layer contains a polyether ester amide resin as a main component. Here, “main component” means that the polyether ester amide resin is contained in an amount of 50% by weight or more of the solid component. Other resins or the like may be mixed within a range that does not detract from the spirit of the present invention and satisfies the condition that the surface resistance of the antistatic layer is from 10 ⁹ Ω to 10 ¹² Ω. Moreover, the case where it consists only of polyetheresteramide resin may be sufficient. In particular, it is preferable that the polyether ester amide resin is 80% by weight or more of the solid component because the gist of the present invention is easily achieved.

The antistatic layer may contain a metal salt composed of a halide of an alkali metal and / or an alkaline earth metal in addition to the polyether ester amide resin or the like. By containing these, the antistatic effect can be further improved, and the condition that the surface resistance of the antistatic layer is 10 ⁹ Ω or more can be more easily satisfied. For example, when selecting from the polyether ester amide resins disclosed in JP-A-7-10989, the selection range can be expanded.

Examples of the metal salt comprising an alkali metal and / or alkaline earth metal halide include lithium chloride, sodium chloride, potassium chloride, magnesium chloride, calcium chloride, sodium bromide, potassium bromide and magnesium bromide. it can. Of these, sodium chloride and potassium chloride are preferable. The amount of the metal salt used is in a range where the surface resistance of the antistatic layer is from 10 ⁹ Ω to 10 ¹² Ω, and the surface resistance of the antistatic layer can be adjusted by adjusting the amount of use. In addition, since it will precipitate on the surface of an insulated wire and the external appearance will be impaired when it exceeds 5 weight% in an antistatic layer, 5 weight% or less is preferable.

The antistatic layer may contain a nonionic, anionic, cationic or amphoteric surfactant in addition to the polyetheresteramide resin or the like. By containing these, the antistatic effect can be further improved, and the condition that the surface resistance of the antistatic layer is 10 ⁹ Ω or more can be more easily satisfied. You may contain both this surfactant and the said metal salt. Among these surfactants, anionic surfactants, particularly sulfonates such as alkylbenzene sulfonate, alkyl sulfonate, and paraffin sulfonate are preferable.

In the insulated wire of the present invention, the surface resistance of the antistatic layer is in the range of 10 ⁹ Ω to 10 ¹² Ω. Here, the “surface resistance” refers to a resistance value specific to the material of the antistatic layer, and refers to a resistance value (unit: Ω) per 1 cm width of an insulated wire in which the antistatic layer is provided with a thickness of 5 μm.

Since the surface resistance of the antistatic layer is 10 ⁹ Ω or more, a short circuit between the exposed conductor at the end of the insulated wire and the antistatic layer on the surface of the insulated wire is unlikely to occur, and the antistatic layer of the insulated wire terminal is peeled off during use Is unnecessary. Furthermore, it becomes possible to reduce the leakage current during AC energization, and the antistatic layer can more effectively suppress deterioration due to heat generation.

On the other hand, since the surface resistance of the antistatic layer is 10 ¹² Ω or less, the equipotential state between the antistatic layers of the insulated wire forming the electric coil is maintained. As a result, since the concentration of the electric field between the insulated wires is relaxed, the partial discharge starting voltage becomes high, and even when a high voltage is applied to the coil, the occurrence of partial discharge is effectively prevented, and dielectric breakdown due to partial discharge is prevented. It becomes possible to prevent effectively. As a result, the life of electric equipment using this insulated wire, such as a motor, can be extended.

  The invention according to claim 2 is the insulated wire according to claim 1, wherein the antistatic layer has a thickness of 0.1 μm to 10 μm. The thickness of the antistatic layer is preferably 0.1 μm or more and 10 μm or less. If the thickness is less than 0.1 μm, uniform coating in the circumferential direction tends to be difficult. On the other hand, if the thickness exceeds 10 μm, mechanical characteristics such as wear characteristics tend to be lowered.

  The invention according to claim 3 is the insulated wire according to claim 1 or 2, wherein the partial discharge start voltage is 1.0 kV or more. The partial discharge start voltage is preferably 1.0 kV or higher. In recent years, in order to obtain a small and high output motor, it is desired to increase the voltage applied to the electric coil. However, by setting the partial discharge start voltage to 1.0 kV or more, the generation of partial discharge is effective. The voltage applied to the electric coil can be increased.

  The present invention provides an electric coil and a motor using the insulated wire in addition to the insulated wire. That is, the invention of claim 4 is an electric coil formed by winding the insulated wire according to any one of claims 1 to 3, and the invention of claim 5 is a claim. A motor having the electric coil according to 4.

  The insulated wire according to the present invention has a high partial discharge starting voltage, and the occurrence of dielectric breakdown due to partial discharge is suppressed. Moreover, it is possible to manufacture without using a varnish requiring a complicated manufacturing process. Since the electric coil of the present invention using this insulated wire and the motor of the present invention using this electric coil have suppressed partial discharge, the occurrence of dielectric breakdown is small even when a high voltage is applied, The processing cost can also be reduced.

  Next, specific modes for carrying out the present invention, particularly the best mode, will be described with reference to the drawings and examples. However, the scope of the present invention is not limited to only these modes and examples. Various changes can be made without departing from the spirit of the present invention.

  FIG. 1 is a cross-sectional view of an example of the insulated wire of the present invention. 1 in FIG. 1 represents an example of the insulated wire of the present invention. As shown in FIG. 1, the insulated wire 1 includes a conductor 2, an insulating layer 3 formed on the conductor 2, and an antistatic layer 4 formed on the insulating layer 3.

  As the conductor 2, copper or copper alloy wire can be cited as a representative example, but the material and configuration are not particularly limited as long as the conductor 2 has conductivity and strength required for the electric wire. Materials include other metal wires such as silver wire and aluminum wire, tin-plated copper wire, aluminum alloy wire, steel core aluminum wire, copper fly wire, nickel-plated copper wire, silver-plated copper wire, copper-covered aluminum wire, etc. Is mentioned. The diameter of the conductor and its cross-sectional shape are not particularly limited. The cross-sectional shape is not limited to a round shape, and may be a polygonal shape such as a flat angle or a hexagon. In addition, the diameter of the conductor is preferably 0.1 mm to 3.0 mm from the viewpoint of being applied to a wide range of applications such as a motor or an electric coil that loads a high voltage.

  The resin used for the insulating layer 3 is not particularly limited as long as the resin has high insulating properties, but a resin having high heat resistance is preferable. Such resins include polyethersulfone resin, polyetherimide resin, polyetheretherketone resin, tetrafluoroethylene / hexafluoropropylene copolymer resin, thermoplastic polyimide resin, polyamideimide resin, polyesterimide resin, H type A polyester resin etc. can be mentioned.

  Among these, a resin having a long-term insulation heat resistance temperature of 150 ° C. or higher is preferable. By setting the long-term insulating heat-resistant temperature of the insulating layer 3 to 150 ° C. or higher, an insulated wire that can withstand long-term use at high temperatures can be obtained. Here, the long-term insulation heat resistance temperature is a heat resistance temperature indicated by a heat resistance index of JISC3003-1999, and the predetermined breakdown voltage when the dielectric breakdown voltage after heat treatment at a predetermined temperature for 20000 hours is a predetermined test voltage. Say. Examples of the resin having a long-term insulation heat-resistant temperature of 150 ° C. or higher include polyimide resin, polyamideimide resin, polyesterimide resin, and H-type polyester resin.

  In addition, as resin used for the insulating layer 3, one type of resin may be used alone, or two or more types may be used in combination. The insulating layer 3 may have a multilayer structure. That is, it may be composed of two or more layers formed of different materials. Furthermore, the insulating layer 3 may contain various additives such as a lubricant, an inorganic filler, and the like. As the additive and the inorganic filler, those similar to those used in the insulating layer of conventional insulated wires can be used.

The antistatic layer 4 is composed mainly of a polyether ester amide resin, and its surface resistance is in the range of 10 ⁹ Ω to 10 ¹² Ω. As described above, in addition to the polyether ester amide resin, other resins, etc., as long as the purpose of the present invention is not impaired and the surface resistance of the antistatic layer satisfies the condition of 10 ⁹ Ω to 10 ¹² Ω. Or a metal salt composed of a halide of an alkali metal and / or an alkaline earth metal, and a nonionic, anionic, cationic or amphoteric surfactant. Furthermore, other components such as an antioxidant and a plastic component for improving adhesiveness may be added as long as the characteristics are not impaired.

  The antistatic layer 4 may be kneaded with a conductive filler such as carbon black, carbon nanotube, gold, silver or other metal particles. However, the kneading of the conductive filler complicates the production of the varnish, may affect the discharge start voltage, and if the kneading is insufficient, the mechanical properties (flexibility) of the insulated wire 1 are reduced. Therefore, it is limited to a range where such a problem does not occur, that is, a range where the gist of the present invention is not impaired. Among conductive fillers, carbon black is preferably used because of its good dispersion stability with respect to the resin.

  The insulated wire of the present invention can be produced by a method of forming an insulating layer on a conductor and then forming an antistatic layer on the insulating layer.

  The method for forming the insulating layer can be performed in the same manner as the formation of the insulating layer in the production of a conventional insulated wire. That is, an insulating layer can be obtained by applying and baking on a conductor a varnish obtained by dissolving a resin constituting the insulating layer in a solvent. Solvents used in the varnish, coating and baking conditions are the same as those for conventional insulated wires. When an insulating layer consists of two or more layers, this process can be manufactured by changing the kind of resin and repeating. The thickness of the insulating layer is determined in consideration of the degree of physical properties required for the insulated wire, the diameter of the conductor, and the like. Usually, it is 2 type-0 type shown by JIS C3003 5 paragraph.

  The antistatic layer can also be formed in the same manner as the insulating layer. That is, an antistatic layer can be obtained by applying and baking a varnish obtained by dissolving a polyether ester amide resin or a mixture containing a main component thereof in an organic solvent on an insulating layer formed on a conductor. . The varnish can be applied in the same manner as in the case of forming a conventional insulating layer. The organic solvent is not particularly limited as long as it can dissolve or uniformly disperse the polyetheresteramide resin and other components. For example, cresol etc. are mentioned.

  The cross-sectional shape of the insulated wire of the present invention thus obtained is not limited to a circle but may be a polygonal shape such as a flat or hexagonal shape.

  The electric coil of the present invention can be obtained by winding the insulated wire obtained as described above. Winding can be performed by the same method and conditions as in the case of obtaining an electric coil from a conventional insulated wire. Moreover, the motor of the present invention can be configured by using the electric coil of the present invention as a rotor or a stator. The method of using it as a rotor or a stator is the same as when using a conventional electric coil for a motor.

  A surface lubricating layer for imparting lubricity to the surface of the insulated wire may be provided on the outer layer of the antistatic layer 4, that is, the outermost layer of the insulated wire, within a range that does not reduce the partial discharge suppression effect after the fusion treatment. . Providing a surface lubrication layer is preferable because it improves workability when the insulated wire 1 is wound to form an electric coil and scratches are less likely to occur on the insulated wire surface. As the surface lubricating layer, a coating film of paraffins such as liquid paraffin and solid paraffin can also be used. Moreover, you may provide a flame retardant layer etc. in the insulated wire of this invention as needed.

In the electric coil, by providing a layer mainly composed of polyetheresteramide resin and having a surface resistance of 10 ⁹ Ω to 10 ¹² Ω between the insulated wires, the spirit of the present invention is not impaired. Thus, it is possible to obtain an electric coil that is more excellent in partial discharge suppression effect. For example, even when the contact between the insulated wires forming the electric coil is insufficient, the partial discharge start voltage can be increased and the leakage current can be reduced. Furthermore, an electric coil formed by winding an insulated wire having a conductor and an insulating layer formed on the conductor, even if the insulated wire is other than the insulated wire of the present invention, By providing a layer having a polyether ester amide resin as a main component and a surface resistance of 10 ⁹ Ω to 10 ¹² Ω, an electric coil with excellent partial discharge suppression effect and a small leakage current can be obtained.

Example 1
(Production of insulated wires)
A polyamide resin insulating varnish (manufactured by Hitachi Chemical Co., Ltd., trade name HI-406) was applied onto a copper conductor having a diameter of 1.0 mm and baked in a vertical baking furnace to form an insulating layer. After that, a varnish obtained by dissolving a resin composition mainly composed of a polyether ester amide resin (an antistatic resin manufactured by Sanyo Kasei Kogyo Co., Ltd., trade name Pelestat NC6321) in cresol to a solid content of 25% on the insulating layer Application and baking were performed to form an antistatic layer, and an insulated wire was produced. The finished outer diameter of the insulated wire was 1.068 mm, the thickness of the insulating layer was 30 μm, and the thickness of the antistatic layer was 4 μm. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Example 2
An insulated wire was produced under the same conditions as in Example 1 except that the thickness of the insulating layer was 32 μm and the thickness of the antistatic layer was 2.0 μm. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Example 3
An insulated wire was produced under the same conditions as in Example 1 except that perestat NC7530 (a resin composition containing a polyetheresteramide resin as a main component, an antistatic resin manufactured by Sanyo Chemical Industries, Ltd.) was used instead of perestat NC6321. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Comparative Example 1
An insulated wire was produced under the same conditions as in Example 1 except that the antistatic layer was not formed and the thickness of the insulating layer was 34 μm.

Example 4
An insulated wire was produced under the same conditions as in Example 1 except that a polyesterimide resin insulating varnish (manufactured by Altana Co., Ltd., trade name Isomid 40SM45) was used instead of the polyamide resin insulating varnish HI-406. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Comparative Example 2
An insulated wire was produced under the same conditions as in Example 4 except that the antistatic layer was not formed and the thickness of the insulating layer was 34 μm.

Example 5
Polyesterimide resin insulating varnish Isomid 40SM45 was applied onto a copper conductor having a diameter of 1.0 mm and baked in a vertical baking furnace to form an insulating layer lower layer. Thereafter, a polyamide resin insulating varnish HI-406 was applied on the insulating layer lower layer and baked in a vertical baking furnace to form an insulating layer upper layer. Thereafter, a varnish obtained by dissolving the resin composition Pelestat NC6321 mainly composed of polyetheresteramide resin in cresol to a solid content of 25% is applied and baked on the upper layer of the insulating layer to form an antistatic layer. An insulated wire was produced. The finished outer diameter of the insulated wire was 1.068 mm, the thickness of the insulating layer lower layer was 25 μm, the thickness of the insulating layer upper layer was 5 μm, and the thickness of the antistatic layer was 4 μm. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Comparative Example 3
An insulated wire was produced under the same conditions as in Example 5 except that the antistatic layer was not formed and the thickness of the upper layer of the insulating layer was 9 μm.

Example 6
An insulated wire was produced under the same conditions as in Example 1 except that a polyimide resin insulating varnish (product name: Pire-ML) was used instead of the polyamide resin insulating varnish HI-406. In the manufactured insulated wire, no abnormality in the appearance in the normal state was observed.

Comparative Example 4
An insulated wire was produced under the same conditions as in Example 6 except that the antistatic layer was not formed and the thickness of the insulating layer was 34 μm.

  About each insulated wire produced as mentioned above, the surface resistance and the partial discharge starting voltage were measured by the following measuring method. The results are shown in Tables 1 and 2.

<Measurement of surface resistance>
A silver paste having a width of 1 cm (trade name Dotite D550, manufactured by Fujikura Kasei Co., Ltd.) was applied to the surface of the manufactured insulated wire, and three electrodes were formed at intervals of 1 cm. And the resistance value between each electrode was measured using the insulation resistance meter (Yokogawa Hewlett-Packard company make, brand name 4329A), and the surface resistance of the antistatic layer was measured by calculating the average value.

<Partial discharge start voltage measurement>
Based on the two-strand method defined in JIS-C3003-1999, the measurement was performed using a partial discharge tester (trade name QM-50, manufactured by Mitsubishi Cable Industries, Ltd.). Specifically, as shown in FIG. 2, two windings are twisted and an AC voltage is applied to both ends of the two windings. The voltage is increased at a rate of 70 V / sec, and the voltage when the discharge amount reaches 100 pC is taken as the measurement value.

From the results shown in Tables 1 and 2, the antistatic layer has a polyether ester amide resin as a main component and a surface resistance of 2.8 to 3.5 × 10 ¹⁰ Ω (within a range of 10 ⁹ Ω to 10 ¹² Ω). The insulated wire of the example (example of the present invention) provided with a partial discharge start voltage of 1.1 kV or higher is shown to have an excellent partial discharge suppression effect. This effect is the same even if the type of resin of the insulating layer is changed. On the other hand, the insulated wire of the comparative example in which the antistatic layer is not provided can only obtain a partial discharge start voltage lower than 1.0 kV, although the thickness and material of the insulating layer are the same as those in the example. It has been shown that the effect of suppressing discharge is insufficient.

It is sectional drawing of an example of the insulated wire of this invention. It is a figure explaining the test body for partial discharge start voltage measurement.

Explanation of symbols

1. Insulated wire Conductor 3. Insulating layer 4. Antistatic layer

Claims (5)

An insulated wire having a conductor, an insulating layer covering the conductor, and an antistatic layer covering the insulating layer,
The insulated wire is characterized in that the antistatic layer comprises a polyetheresteramide resin as a main component, and the surface resistance of the antistatic layer is 10 ⁹ Ω or more and 10 ¹² Ω or less.   The insulated wire according to claim 1, wherein the antistatic layer has a thickness of 0.1 μm or more and 10 μm or less.   The insulated wire according to claim 1 or 2, wherein a partial discharge start voltage is 1.0 kV or more.   An electric coil comprising the insulated wire according to any one of claims 1 to 3.   A motor comprising the electric coil according to claim 4.

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