JP2012244861A - Insulation coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation coil in which a voltage resistance property is improved and a heat radiation property is also improved without making an insulation layer thicker than needed.SOLUTION: An insulation coil comprises a coil conductor and an insulation layer obtained by winding an insulation tape for which a mica layer sheet is adhered to a reinforcing material by a binder resin, around the coil conductor, and impregnating and hardening a thermosetting resin. The reinforcing material contains an inorganic aggregation filler which has an average secondary particle size within a specific range, in 8 wt.% or more and 70 wt.% or less with respect to a resin component in the insulation layer.

Description

  The present invention relates to an insulating coil excellent in heat dissipation and withstand voltage characteristics.

  In a high-output rotating electrical machine, it is necessary to improve the thermal conductivity of the insulating coil in order to efficiently dissipate the generated heat. Conventionally, it has been attempted to use an insulating material with high thermal conductivity for the insulating coating of the insulating coil. ing.

  As a coil insulated with a highly heat-conductive insulating material, a conductor made of an insulating material comprising a mica flake layer fixed to a glass fiber woven fabric and an impregnating resin disposed in a space between the mica flake layers and containing inorganic particles Insulated coils are known. The inorganic particles have a thermal conductivity of 5 W / mK or more, and at least 90% by weight have a particle size of 0.1 to 15 μm. Specifically, boron nitride, aluminum nitride, silicon nitride, Examples thereof include aluminum oxide, magnesium oxide, beryllium oxide, and silicon carbide.

  Such an insulating coil is manufactured by the method shown below, for example. As a first method, a liquid resin is impregnated into an insulating tape made of a mica flake layer fixed to a glass fiber woven fabric before being wound around a coil conductor, and the surface of the insulating tape impregnated with this resin is impregnated. In this method, inorganic particles are coated, and the insulating tape coated with the inorganic particles is wound around a coil conductor (see, for example, Patent Document 1).

  Furthermore, as a second method, a liquid resin containing inorganic particles with high thermal conductivity is coated on an insulating tape made of a mica flake layer fixed to a glass fiber woven fabric before being wound around a coil conductor, In this method, an insulating tape coated with an inorganic particle-containing resin is wound around a coil conductor (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 63-110929 (especially pages 4 to 6) Japanese Patent Laid-Open No. 11-206056 (particularly, page 3)

  In order to achieve high thermal conductivity in the above-described prior art insulating coil, not only glass fibers and resins having low thermal conductivity but also large amounts of inorganic particles are interposed between the mica flake layers in the insulating layer formed by winding the insulating tape. It needs to exist. However, in such an insulating tape, the layer containing inorganic particles becomes thick, and as a result, the insulating layer itself becomes thick.

  The withstand voltage characteristics of the insulating coil generally depend on the number of mica flake layers in the insulating layer, and the greater the number of layers, the better the withstand voltage characteristics. However, since the insulating coil is inserted into the slot groove of the stator of the rotating electric machine, the thickness of the insulating layer of the insulating coil is limited. In the above-described prior art, the layer containing inorganic particles becomes thick, and the insulating layer The number of mica flake layers inside must be reduced, the withstand voltage characteristics are reduced, and the flexibility of the insulating tape becomes insufficient, making it difficult to wind the insulating tape along the coil conductor. There was a problem of becoming.

  Accordingly, the present invention has been made to solve the above-described problems, and an insulating coil that has improved withstand voltage characteristics and excellent heat dissipation without increasing the thickness of the insulating layer more than necessary. It is intended to provide.

  The present invention is an insulating coil comprising a coil conductor and an insulating layer obtained by winding an insulating tape in which a mica layer sheet is bonded to a reinforcing material with a binder resin around the coil conductor and impregnating a thermosetting resin. The reinforcing material contains an agglomerated inorganic filler having an average secondary particle diameter of 15 μm or more and 70 μm or less in an amount of 8% by weight or more and 70% by weight or less based on the resin component in the insulating layer. It is an insulation coil.

  According to the present invention, it is possible to provide an insulating coil that can improve the withstand voltage characteristics without increasing the thickness of the insulating layer more than necessary and is excellent in heat dissipation.

It is a schematic cross section of the insulated coil by Embodiment 1 of this invention. It is a schematic cross section of the insulation tape used for preparation of the insulation coil by Embodiment 1 of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view of an insulating coil according to the first embodiment.
In FIG. 1, the insulating coil according to Embodiment 1 includes a coil conductor 1 and an insulating tape 4 in which a mica layer sheet 2 is bonded to a reinforcing material 3 with a binder resin, and a reinforcing material in which the outermost layer of the insulating coil is an insulating tape 4. 3 and the insulating layer 5 wound around the coil conductor 1 and impregnated with a thermosetting resin and cured. FIG. 2 is a partially enlarged schematic cross-sectional view of the insulating tape 4. In FIG. 2, the reinforcing material 3 supports and reinforces the mica layer sheet 2. The reinforcing material 3 is composed of a reinforcing base material 6, an aggregated inorganic filler 7 and a resin 8 filled in a gap between the reinforcing base material 6.

  The mica layer sheet 2 is made of mica foil such as laminated mica foil or flake mica foil, and a resin for bonding the mica foil. As this resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, or the like is used.

  The reinforcing substrate 6 only needs to have a gap that can be filled with the aggregated inorganic filler 7, and examples thereof include glass cloth, polyimide film (for example, Kapton (registered trademark) film), polyethylene terephthalate film, and the like. Among these, the glass cloth is preferable in that the tensile strength of the insulating tape 4 is increased, the insulating tape 4 can be easily wound around the coil conductor 1, and the thermal conductivity of the insulating layer 5 can be increased. Moreover, the preferable opening ratio of the reinforcement base material 6 is 80% or more and 98% or less. The thickness of the reinforcing substrate 6 is usually in the range of 20 μm or more and 50 μm or less. Among them, the average secondary particle diameter of the aggregated inorganic filler 7 is preferably from the viewpoint of thermal conductivity and withstand voltage characteristics. It is preferable to be 6 times or more and 2 times or less.

  Examples of the resin 8 filled in the gaps of the reinforcing base 6 include epoxy resins, unsaturated polyester resins, and phenol resins.

  The aggregated inorganic filler 7 is an aggregate of inorganic particles having a thermal conductivity higher than that of mica, specifically, an aggregate of inorganic particles having a thermal conductivity of 5 W / m · K or more. Specific examples of such agglomerated inorganic filler 7 include boron nitride particle aggregates, aluminum nitride particle aggregates, silicon nitride particle aggregates, aluminum oxide particle aggregates, magnesium oxide particle aggregates, beryllium oxide particle aggregates, A silicon carbide particle aggregate is mentioned. One kind of these agglomerated inorganic fillers 7 may be used, or a plurality of kinds may be mixed and used. The agglomerated inorganic filler 7 may be agglomerated and fixed two or more of the same kind of inorganic particles, or may be agglomerated and fixed of two or more different kinds of inorganic particles.

The average secondary particle diameter (average particle diameter of the aggregate) of the aggregated inorganic filler 7 needs to be 15 μm or more and 70 μm or less, and preferably 17 μm or more and 60 μm or less. When the average secondary particle diameter of the aggregated inorganic filler 7 is less than 15 μm, the desired thermal conductivity cannot be obtained, and the aggregated inorganic filler 7 flows out from the gaps in the reinforcing base 6. On the other hand, when the average secondary particle diameter of the aggregated inorganic filler 7 is more than 70 μm, the insulating layer 5 becomes thicker than necessary, and when the produced insulating tape 4 is wound or insulated to the coil conductor 1. The mica layer is damaged when the tape 4 is wound. The average particle size (average primary particle size) when the aggregated inorganic filler 7 is deagglomerated is preferably 50 μm or less.
By using the agglomerated inorganic filler 7 having such a specific average secondary particle size, the contact area between the resin 8 and the surface of the agglomerated inorganic filler 7 is increased. 8 enters and the adhesive strength between the mica layer sheet 2 and the reinforcing material 3 is improved. Further, the aggregated inorganic filler 7 is appropriately deagglomerated when the insulating tape 4 is wound around the coil conductor 1, so that the aggregated inorganic filler 7 is dispersed in the reinforcing material 3 without falling off the reinforcing material 3. The aggregated inorganic filler 7 continues to be present in the reinforcing material 3 without flowing out from the reinforcing material 3 in the subsequent thermosetting resin impregnation step, coil pressurizing step, and curing step.

  The filling amount of the agglomerated inorganic filler 7 depends on the resin components in the insulating layer 5 (the resin used for producing the mica layer sheet 2, the resin used for bonding the mica layer sheet 2 to the reinforcing material 3 and the impregnated heat. It is necessary that the content is 8 wt% or more and 70 wt% or less, preferably 10 wt% or more and 60 wt% or less. When the filling amount of the aggregated inorganic filler 7 is less than 8% by weight, the desired thermal conductivity cannot be obtained, and the resin component ratio in the insulating layer 5 increases, resulting in a thick layer thickness. The desired thermal conductivity cannot be obtained. On the other hand, when the amount of the agglomerated inorganic filler 7 is more than 70% by weight, the insulating layer 5 becomes thicker than necessary and the insulating tape 4 becomes hard. In other words, the mica layer is damaged, it is difficult to wind the insulating tape 4 around the coil conductor 1, and the aggregated inorganic filler 7 falls off the reinforcing material 3.

  Further, the reinforcing material 3 may be filled with an auxiliary inorganic filler having an average primary particle diameter of 10 μm or less together with the above-described aggregated inorganic filler 7. If an auxiliary inorganic filler having an average primary particle size of more than 10 μm is used in combination, the insulating layer 5 may be unnecessarily thick, which is not preferable. Further, the amount of the resin 8 necessary for the insulating layer 5 increases, and as a result, the thermal conductivity may be lowered. Furthermore, when the produced insulating tape 4 is wound up or when the insulating tape 4 is wound around the coil conductor 1, the mica layer may be damaged. The auxiliary inorganic filler having such an average primary particle size does not flow out of the reinforcing material 3 due to the presence of the aggregated inorganic filler 7 having an average secondary particle size of 15 μm or more and 70 μm or less. Will exist. In addition, since the auxiliary inorganic filler is also present in the gaps between the aggregated inorganic fillers 7, it contributes to the improvement of the thermal conductivity.

  When the auxiliary inorganic filler having an average primary particle diameter of 10 μm or less is used in combination, the total amount of the aggregated inorganic filler 7 contained in the reinforcing material 3 is 20% by weight or more and 70% by weight with respect to the resin component in the insulating layer 5. It is desirable to make it not more than% by weight.

Next, a method for manufacturing an insulated coil according to the present embodiment will be described.
In this embodiment, the insulating coil is obtained by applying a slurry containing an agglomerated inorganic filler 7 and a resin 8 to the reinforcing substrate side of an adhesive sheet body in which the mica layer sheet 2 is bonded to the reinforcing substrate 6 with a binder resin. Then, the gap between the reinforcing bases 6 is filled with the agglomerated inorganic filler 7 and the resin 8 to obtain the insulating tape 4, and the coil conductor 1 is arranged so that the mica layer sheet side of the insulating tape 4 is on the coil conductor side. Is wound in a semi-wrapped manner, and then the wound insulating tape 4 (sometimes referred to as a main insulating layer) is impregnated with a liquid thermosetting resin, pressed with a predetermined mold, and cured in a curing furnace. The insulating layer 5 can be manufactured by heating and curing the thermosetting liquid resin. Examples of the liquid thermosetting resin include epoxy resin, unsaturated polyester resin, phenol resin, polyimide resin, maleimide resin, and silicone resin.

  The method for applying the slurry is not particularly limited, and examples thereof include spray coating and roll coating. You may add a hardening | curing agent, a hardening accelerator, etc. to the said slurry. However, when the main agent, the curing agent, and the curing accelerator are mixed, the curing reaction proceeds in the reinforcing base 6 and the insulating tape 4 becomes hard, and it becomes difficult to wind the manufactured insulating tape 4 or the coil. It becomes difficult to wind the conductor 1. An organic solvent can also be used to improve the coating property of the slurry. In this case, it is desirable to volatilize the organic solvent after applying the slurry.

  When the aggregated inorganic filler 7 and the auxiliary inorganic filler having an average primary particle diameter of 10 μm or less are used in combination, the aggregated inorganic filler 7 and the resin 8 and the auxiliary inorganic filler having an average primary particle diameter of 10 μm or less, May be applied to the reinforcing substrate 6 and filled in the reinforcing material 3, or after application of the slurry containing the aggregated inorganic filler 7 and the resin 8, it has an average primary particle size of 10 μm or less. A slurry containing the auxiliary inorganic filler and the resin 8 may be further applied and filled in the reinforcing material 3.

  The insulating coil according to the present embodiment is excellent in thermal conductivity because a reinforcing material (sometimes referred to as a high thermal conductive layer) having a higher thermal conductivity than the mica layer sheet is provided in the insulating layer. Also, the insulation tape used in the production of the insulation coil is flexible and can reduce the thickness of the layer containing the inorganic filler, so it has excellent withstand voltage without making the insulation layer of the insulation coil thicker than necessary. Characteristics can be secured.

Hereinafter, the insulating coil of the present invention will be specifically described with reference to examples and comparative examples.
[Example 1]
Aggregated mica powder was dispersed in water, and the dispersion was made with a paper machine to produce aggregated mica foil. A resin in which 100 parts by weight of bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)}, 10 parts by weight of zinc naphthenate, and 400 parts by weight of methyl ethyl ketone are mixed with this laminated mica foil. The composition is applied by a roll coater method, and the laminated mica foil is bonded to a polyester film having a width of 1000 mm and a thickness of 0.02 mm, which is a temporary support material, and a predetermined length of mica layer. A 1 mm mica layer sheet was prepared.
Bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)} A resin composition prepared by mixing 100 parts by weight of zinc naphthenate and 1000 parts by weight of methyl ethyl ketone is used as a reinforcing group. A glass cloth having a width of 1000 mm, a thickness of 50 μm, and a mesh opening ratio of 97%, which was a predetermined length, was applied by a roll coater method, and then the organic solvent was volatilized to prepare a resin-attached glass cloth sheet.
Next, the resin-attached glass cloth sheet was bonded to the mica layer surface of the mica layer sheet. What was bonded in this way was pressurized with a 60 degreeC hot roll, and the resin adhesion glass cloth sheet was crimped | bonded to the mica layer sheet.
Bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)} and zinc naphthenate are mixed, and an aggregated inorganic filler (nitriding) having an average secondary particle size shown in Table 1 Boron particle aggregates) were added and diluted with methyl ethyl ketone to prepare a slurry of aggregated inorganic filler. In addition, the filling amount of the inorganic filler in Table 1 is a ratio with respect to the resin component in the insulating layer.
After applying this slurry to the resin-attached glass cloth sheet surface in the joined body of the mica layer sheet and the resin-attached glass cloth sheet by a spray method, the organic solvent is volatilized, and the polyester film is pressurized with a 60 ° C. hot roll. An insulating sheet comprising a mica layer sheet and a reinforcing material was obtained. This insulating sheet was cut into a width of 30 mm to obtain an insulating tape.
Next, the insulating tape from which the polyester film was removed was wound around a test bar (50 mm × 12 mm × 1140 mm) by half-lap winding with the mica layer sheet side facing the test bar (coil conductor) side to form a main insulating layer. . At this time, the mica layer was not damaged and the winding property was good. Furthermore, the main insulating layer made of this insulating tape is bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 828 (Japan Epoxy Resin Co., Ltd.)} and methyltetrahydrophthalic anhydride cured by a vacuum pressure impregnation method. A thermosetting resin composition comprising an agent {trade name: HN-2200 (Hitachi Chemical Co., Ltd.)} was impregnated. The main insulating layer was clamped with a jig so as to have an insulating thickness of 4.26 mm, heated in a drying furnace, and the resin was cured to produce a test insulating coil.

Next, the thermal conductivity and withstand voltage characteristics of the insulating layer of the obtained test insulating coil were evaluated.
The thermal conductivity of the insulating layer was measured using a thermal conductivity measuring device {Model: TXP-03 (Miki Scientific System Co., Ltd.)} for the test piece cut out from the insulating layer of the test insulating coil.
The withstand voltage characteristics were obtained from the voltage at which dielectric breakdown occurred when a voltage was applied to the test piece cut out from the insulating layer of the test insulating coil at 25 ° C. by the step-by-step method. The results are shown in Table 2.

[Examples 2 and 3]
Insulation for test in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used and the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 was blended into the slurry. A coil was produced. In any of the examples, the mica layer was not damaged and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Examples 4 to 9]
Using the reinforcing substrate shown in Table 1, slurry of the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter and the auxiliary inorganic filler (boron nitride particles) having the average primary particle diameter shown in Table 1 A test insulating coil was produced in the same manner as in Example 1 except that it was blended into the above. In any of the examples, the mica layer was not damaged and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Examples 10 to 14]
After using the reinforcing base shown in Table 1 and blending the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 into the slurry and applying the aggregated inorganic filler slurry, bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)} and zinc naphthenate are mixed, and an auxiliary inorganic filler (boron nitride particles) having an average primary particle size shown in Table 1 ) And a slurry of the auxiliary inorganic filler obtained by diluting with methyl ethyl ketone was applied in the same manner as in Example 1 to produce a test insulating coil. In any of the examples, the mica layer was not damaged and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 1]
An insulating coil for testing was produced in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used and the agglomerated inorganic filler having the average secondary particle diameter shown in Table 1 was added to the slurry. The mica layer did not break during the production of the test insulating coil, and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 2]
Using the reinforcing substrate shown in Table 1, slurry of the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter and the auxiliary inorganic filler (boron nitride particles) having the average primary particle diameter shown in Table 1 A test insulating coil was produced in the same manner as in Example 1 except that it was blended into the above. The mica layer did not break during the production of the test insulating coil, and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 3]
After using the reinforcing base shown in Table 1 and blending the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 into the slurry and applying the aggregated inorganic filler slurry, bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)} and zinc naphthenate are mixed, and an auxiliary inorganic filler (boron nitride particles) having an average primary particle size shown in Table 1 Insulating tape was prepared in the same manner as in Example 1 except that a slurry of auxiliary inorganic filler obtained by diluting with methyl ethyl ketone was applied. An attempt was made to produce an insulating coil for testing using this insulating tape, and the mica layer was damaged during winding.

[Comparative Example 4]
After using the reinforcing base shown in Table 1 and blending the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 into the slurry and applying the aggregated inorganic filler slurry, bisphenol A type epoxy resin {trade name: Epicoat (registered trademark) 834 (Japan Epoxy Resin Co., Ltd.)} and zinc naphthenate are mixed, and an auxiliary inorganic filler (boron nitride particles) having an average primary particle size shown in Table 1 ) And a slurry of the auxiliary inorganic filler obtained by diluting with methyl ethyl ketone was applied in the same manner as in Example 1 to produce a test insulating coil. The mica layer did not break during the production of the test insulating coil, and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 5]
Insulation for test in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used and the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 was blended into the slurry. A coil was produced. The mica layer did not break during the production of the test insulating coil, and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 6]
An insulating tape was prepared in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used, and the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 was blended into the slurry. Produced. An attempt was made to produce an insulating coil for testing using this insulating tape, and the mica layer was damaged during winding.

[Comparative Example 7]
Insulation for test in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used and the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 was blended into the slurry. A coil was produced. The mica layer did not break during the production of the test insulating coil, and the winding property was good. Table 2 shows the thermal conductivity and withstand voltage characteristics of the insulating layer in the obtained test insulating coil.

[Comparative Example 8]
An insulating tape was prepared in the same manner as in Example 1 except that the reinforcing base material shown in Table 1 was used, and the aggregated inorganic filler (boron nitride particle aggregate) having the average secondary particle diameter shown in Table 1 was blended into the slurry. Produced. An attempt was made to produce an insulating coil for testing using this insulating tape, and the mica layer was damaged during winding.

  As can be seen from the results in Table 2, the insulating coils of Examples 1 to 14 have excellent thermal conductivity and withstand voltage characteristics. On the other hand, all of the insulating coils of Comparative Examples 1, 2, 4, 5 and 7 had low thermal conductivity. In Comparative Examples 3, 6 and 8, the mica layer was damaged when the insulating tape was wound.

  DESCRIPTION OF SYMBOLS 1 Coil conductor, 2 Mica layer sheet, 3 Reinforcement material, 4 Insulation tape, 5 Insulation layer, 6 Reinforcement base material, 7 Aggregation inorganic filler, 8 Resin.

Claims (3)

  An insulating coil comprising: a coil conductor; and an insulating layer obtained by winding an insulating tape in which a mica layer sheet is bonded to a reinforcing material with a binder resin around the coil conductor and impregnating a thermosetting resin. An insulating coil comprising an agglomerated inorganic filler having an average secondary particle diameter of 15 μm or more and 70 μm or less in an amount of 8 wt% or more and 70 wt% or less with respect to the resin component in the insulating layer .   The insulating coil according to claim 1, wherein the reinforcing material further contains an auxiliary inorganic filler having an average primary particle diameter of 10 µm or less.   The total amount of the aggregated inorganic filler and the auxiliary inorganic filler contained in the reinforcing material is 20% by weight or more and 70% by weight or less based on the resin component in the insulating layer. 2. The insulating coil according to 2.

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