JP2012175799A - Rotary electric machine stator, method of manufacturing rotary electric machine stator, and insulation tape for rotary electric machine stator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary electric machine stator which has high thermal conduction characteristics enough against an increase in heating value of a conductor and large insulation characteristics enough for the conductor.SOLUTION: The rotary electric machine stator includes: the conductor formed by bundling a plurality of strands; and an insulation layer which is formed so as to cover an outer peripheral surface of the conductor, and includes a filler layer and a mica layer containing a scale-like hexagonal boron nitride filler having an orientation rate (100)/(002) of 0.04 or larger.

Description

  The present invention relates to a rotating electrical machine stator, a method for manufacturing a rotating electrical machine stator, and an insulating tape for the rotating electrical machine stator.

  Rotating electrical machine equipment is equipment that is used for 20 or 30 years, and in particular, components such as a rotating electrical machine stator constituting a high-voltage rotating electrical machine are required to have insulation capable of withstanding high-voltage stress. At present, an insulating material used for a rotating electric machine stator is a composite of an inorganic material such as mica and a resin such as an epoxy resin or a polyester resin. Mica has long been used as an insulation for high-voltage rotating electrical machines where discharge is unavoidable because it is a material with excellent heat resistance and discharge resistance.

  In general, the insulating material is often formed as an insulating tape by using a glass cloth or a film as a backing material, and affixing a mica layer composed of the above-described composite of mica and resin. In addition, a method has been used in which a tape is wound while a large mica scale called peel mica is attached to form an insulating tape as described above.

  On the other hand, recently, due to improved performance of rotating electrical machine equipment, the amount of heat generated in the conductor portion of the rotating electrical machine stator has increased, and it has been required to increase the thermal conductivity of the insulating material in order to dissipate the generated heat. For this reason, a filler layer containing a filler such as hexagonal boron nitride, magnesium oxide, or alumina is provided on the side of the backing material opposite to the mica layer with respect to the insulating tape composed of the mica layer and the backing material as described above. A new high thermal conductivity mica tape has been developed.

  However, in such a high thermal conductivity mica tape, the thermal conductivity can be improved by providing a filler layer. However, since the thickness of the mica layer is reduced, there is a problem that the electrical insulation characteristics are deteriorated. Therefore, in such a high thermal conductivity mica tape, the thickness of the filler layer relative to the mica layer is appropriately adjusted in consideration of the amount of heat generated in the conductor portion of the rotating electrical machine stator described above.

  In order to solve such a problem, according to Patent Document 1, it is disclosed that a hexagonal boron nitride powder having a crystallization index of 1.8 or more is used as a filler to be contained in a filler layer. Since hexagonal boron nitride improves the thermal conductivity by increasing the crystallization index, the thermal conductivity can be improved while maintaining the electrical insulation characteristics.

  However, with the improvement in thermal conductivity by the above-described technology, it is difficult to sufficiently cope with the amount of heat generated in the conductor part of a recent rotating electrical machine stator.

JP 2010-166809 A

  The problem to be solved by the present invention is to provide a rotating electrical machine stator having heat conduction characteristics that can sufficiently cope with an increase in the amount of heat generated in a conductor, and sufficient insulation characteristics for the conductor.

  In the rotating electrical machine stator according to one aspect of the present invention, the orientation rate (100) / (002) formed so as to cover a conductor formed by binding a plurality of strands and the outer peripheral surface of the conductor is 0. And an insulating layer having a mica layer and a filler layer containing a flaky hexagonal boron nitride filler that is 0.04 or more.

  ADVANTAGE OF THE INVENTION According to this invention, the rotary electric machine stator which has the heat conduction characteristic which can fully cope with the increase in the emitted-heat amount in a conductor, and sufficient insulation characteristic with respect to a conductor can be provided.

It is a perspective view of the rotary electric machine stator in embodiment. It is sectional drawing of the rotary electric machine stator shown in FIG. It is sectional drawing which expands and shows the insulating layer of the rotary electric machine stator shown in FIG.1 and FIG.2. It is sectional drawing which shows an example of the specific aspect of the insulating layer shown in FIG. It is process drawing for demonstrating the manufacturing method of the rotary electric machine stator 10 of embodiment. It is a graph which shows the relationship between the orientation rate (100) / (002) of a hexagonal boron nitride filler in a filler layer in an Example, and thermal conductivity.

  FIG. 1 is a perspective view of a rotating electrical machine stator in the present embodiment, and FIG. 2 is a cross-sectional view of the rotating electrical machine stator shown in FIG. 3 is an enlarged cross-sectional view showing an insulating layer of the rotating electric machine stator shown in FIGS. 1 and 2, and FIG. 4 is a cross-sectional view showing an example of a specific mode of the insulating layer shown in FIG. .

  As shown in FIGS. 1 and 2, the rotating electrical machine stator 10 according to this embodiment includes a conductor 11 and an insulating layer 12 formed so as to cover the outer periphery of the conductor 11.

  The conductor 11 is composed of a plurality of strands 111 that are good electrical conductors, for example, copper, aluminum, silver, and the like, and the strands 111 are arranged in parallel and bundled in the vertical and horizontal directions. In the present embodiment, the strands 111 are bundled in parallel in two rows horizontally and eight rows vertically, but the number and arrangement configuration are not particularly limited.

  As shown in FIG. 3, the insulating layer 12 includes a filler layer 121 and a mica layer 122. The filler layer 121 includes, for example, a flaky hexagonal boron nitride filler 121A having an aspect ratio of 1 to 100 or more and a resin 121B. Specifically, it has a configuration in which scale-like hexagonal boron nitride filler 121A is dispersed in a matrix made of resin 121B. The resin 121B can be composed of a general-purpose thermosetting resin.

  Here, the aspect ratio means the ratio of the lengths of the main surfaces that characterize the shape of the scale-like hexagonal boron nitride filler 121A when the thickness is 1. That is, when the thickness is 1, it means that the length of the main surface is 100 or more.

  In the present embodiment, the orientation ratio (100) / (002) of the scale-like hexagonal boron nitride filler 121A in the filler layer 121 is 0.04 or more, preferably 0.05 or more. The scale-like hexagonal boron nitride filler 121A as described above has a z-axis orientation in the thickness direction and an a-axis orientation in the length direction of the main surface. Therefore, the above-described orientation ratio indicates the ratio of the scale-like hexagonal boron nitride filler 121A rising in the direction perpendicular to the film surface of the insulating layer 12.

  In other words, the orientation ratio (100) / (002) of the flaky hexagonal boron nitride filler 121A in the filler layer 121 in this embodiment is 0.04 or more means that the flaky hexagonal boron nitride filler 121A is It means that the ratio of rising in the direction perpendicular to the film surface of the filler layer 121 is 0.04 or more.

  Note that (100) and (002) in the orientation ratio mean the crystallographic orientation direction of the so-called flaky hexagonal boron nitride filler 121A, and in this embodiment, the film surface of the filler layer 121. X-ray irradiation was obtained by X-ray diffraction.

  In general, when the scale-like hexagonal boron nitride filler 121A is formed by dispersing the resin 121B as a matrix to form a layer, the principal surface naturally becomes substantially parallel to the film surface of the filler layer 12 depending on the large aspect ratio. Tend to be contained. However, when the scale-like hexagonal boron nitride filler 121A is contained so as to be substantially parallel to the film surface, the heat generated in the conductor 11 is transferred substantially through the resin 121B. Therefore, depending on the inclusion form, the thermal conductivity is not so much improved in the thickness direction of the filler layer 12.

  On the other hand, in the present embodiment, the scale-like hexagonal boron nitride filler 121A in the filler layer 121 has a degree of orientation (100) / (002) of 0.04 or more, that is, a scale-like hexagon. Since the crystalline boron nitride filler 121A rises in a direction perpendicular to the film surface of the filler layer 121, heat generated in the conductor 11 is transmitted through the flaky hexagonal boron nitride filler 121A at a certain rate. It will be. Therefore, the thermal conductivity in the thickness direction of the filler layer 121 increases depending on the form of inclusion.

  Further, as described above, the scale-like hexagonal boron nitride filler 121A has a major surface having a length in the a-axis and a thickness direction in the z-axis. (Filler) has a higher thermal conductivity in the a-axis direction than in the z-axis direction. Therefore, as in this embodiment, the orientation ratio (100) / (002) becomes 0.04 or more, and the scale-like hexagonal boron nitride filler 121A rises in a direction perpendicular to the film surface. Since the a-axis of the hexagonal boron nitride filler 121A rises in the direction perpendicular to the film surface, the thermal conductivity in the thickness direction of the filler layer 121 is further increased.

  Accordingly, since the thermal conductivity of the filler layer 121 in the insulating layer 12 is improved, the heat generated in the conductor 11 is efficiently released outward through the filler layer 121 of the insulating layer 12.

  The ratio of the resin 121B in the filler layer 121 is not particularly limited, but is preferably 10% by volume or more and 30% by volume or less. If the lower limit of the amount of the resin 121B is smaller than 10% by volume, voids are generated in the filler layer 121, and the thermal conductivity of the scaly hexagonal boron nitride filler 121A may not be improved. When the amount of the resin 121B exceeds 30% by volume, the amount of the scale-like hexagonal boron nitride filler 121A is relatively decreased, and thus the thermal conductivity of the filler layer 121 may be decreased.

  The mica layer 122 in the insulating layer 12 includes, for example, scaly mica filler 122A having an aspect ratio of 1: 100 or more and a resin 122B. Specifically, it has a configuration in which scaly mica filler 121A is dispersed in a matrix made of resin 122B. The resin 122B can be composed of a general-purpose thermosetting resin.

  Here, the aspect ratio means the ratio of the lengths of the main surfaces that characterize the shape when the thickness of the scaly mica filler 122A is 1. That is, when the thickness is 1, it means that the length of the main surface is 100 or more.

  When the layer is formed by dispersing the resin 122B as a matrix, the scaly mica filler 122A is contained so that the main surface is substantially parallel to the film surface of the mica layer 122 depending on the large aspect ratio. Tend. Thus, when the scale-like mica filler 122A is contained so as to be substantially parallel to the film surface, the main surface rises in the vertical direction with respect to the electric field generated in the conductor 11, so that the electric field is shielded. The effect is increased. That is, the insulating characteristics in the thickness direction of the mica layer 122 are improved depending on the inclusion form.

  In addition, since the mica itself has a high insulating property and a high shielding effect against an electric field, the mica layer 122 exhibits high insulating properties in combination with the above-described form of the mica filler 122A in the mica layer 122. become.

  The ratio of the resin 122B in the mica layer 122 is not particularly limited, but is preferably 10% by volume or more and 30% by volume or less. If the lower limit value of the amount of the resin 122B is less than 10% by volume, voids may be generated in the mica layer 122 and the dielectric strength may be reduced. When the amount of the resin 122B exceeds 30% by volume, the amount of the mica filler 122B is relatively decreased, and thus the insulating characteristics of the mica layer 122 may be deteriorated.

  As mentioned above, since the rotary electric machine stator 10 of this embodiment has the insulating layer 12 containing the highly heat conductive filler layer 121 and the high insulation characteristic 122 around the conductor 11, the calorific value of the conductor 11 is increased. It has heat conduction characteristics that sufficiently cope with the increase, and sufficient insulation characteristics for power generation on the conductor 11.

  In the present embodiment, the mica filler 122A in the mica layer 122 has a high aspect ratio. However, even if the mica filler 122A is in the form of particles, the mica itself has high insulating properties. It has sufficiently high insulation characteristics. However, as described above, the insulating properties of the mica layer 122 can be further improved by using a scaly thing.

  In the present embodiment, as shown in FIG. 3, the insulating layer 12 has a backing layer 123 between the filler layer 121 and the mica layer 122. The backing layer 123 can be, for example, a glass cloth, a glass film, or the like. In particular, when the glass cloth is used, a gap between the joints can be impregnated with a thermosetting resin or the like. By providing such a backing layer 123, the strength of the insulating layer 12 can be improved.

  In the present embodiment, the insulating layer 12 with respect to the conductor 11 can be configured as a single layer having a configuration as shown in FIG. 3, but the thicknesses of the filler layer 121 and the mica layer 122 constituting the insulating layer 12 Since it is sufficiently thin, it is usually formed by preparing an insulating tape having a structure as shown in FIG. 3 and winding this tape around the conductor 11 a plurality of times. Specifically, as shown in FIG. 4, the insulating tape having the structure shown in FIG. 3 is wound a plurality of times so that about half of the width of each turn overlaps each other (half wrap).

  The number of windings varies depending on the desired thickness of the insulating layer 12 and the thickness of the insulating tape, but usually 6 to 30 times, that is, 6 to 30 layers of insulating tape are laminated.

  Next, a method for manufacturing the rotating electrical machine stator 10 of the present embodiment will be described focusing on a method for forming the filler layer 121 of the insulating layer 12 in particular.

FIG. 5 is a process diagram for explaining a method for manufacturing the rotating electrical machine stator 10 of the present embodiment.
First, a conductor 11 is prepared in which a plurality of strands 111 that are good electrical conductors are arranged in parallel and bundled in the vertical and horizontal directions, and the outer periphery of the conductor 11 is covered, for example, as shown in FIG. The insulating tape having the configuration is wound a predetermined number of times, for example, 6 to 33 times.

  In this state, the flaky hexagonal boron nitride filler in the filler layer constituting the insulating tape is substantially parallel to the film surface. Further, the resin such as the filler layer is in a B-stage state, for example, without being completely cured.

  Next, a polypropylene tape is wound once by a half wrap around the insulating tape wound a plurality of times. In addition, this propylene tape functions as a mold release material for a fixing jig for fixing an insulating tape described below to the conductor 11.

  Next, an iron plate 21 made of, for example, a cold rolled steel plate (SPCC) is applied to the side surface of the wound insulating tape via the polypropylene tape, and the side surface of the insulating tape is fixed to the side surface of the conductor 11. An iron plate 22 that is the same SPCC is applied to the lower surface of the conductor 11 via the polypropylene tape, and the upper and lower surfaces of the insulating tape are fixed to the upper and lower surfaces of the conductor 11, respectively.

  The iron plates 21 and 22 constitute a fixing jig for the conductor 11 of the insulating tape. Subsequently, the center part of the iron plates 21 and 22 is wound twice by a half wrap with a heat shrink tape, and the iron plates 21 and 22 are fixed. At this time, lead wires (not shown) are attached to the iron plates 21 and 22 so that a voltage can be applied to the iron plates 21 and 22, so that a predetermined voltage can be applied.

Next, the assembly formed as described above is placed in a vacuum pressure tank and evacuated. When sufficiently evacuated, polyethylene wax at 150 ° C. is poured, the assembly is immersed, and heated using polyethylene wax as a medium and a pressure of 7 kgf / cm ² applied with nitrogen gas. Then, the resin constituting the filler layer 121 or the like of the insulating tape is cured to become the resin 121B, and the insulating tape layer that is wound a plurality of times is converted to the insulating layer 12.

  In the present embodiment, a DC or AC voltage that causes an electric field of 1 kV / mm or more between the conductor 11 and the iron plates 21 and 22 is applied via the lead wire during or before the heat curing in the above-described process. Apply a DC or AC voltage such that the electric field is 500 V / mm or more for 1 minute or more. As a result, the flaky hexagonal boron nitride filler 121A in the filler layer 121 rises in a direction perpendicular to the film surface so that the orientation ratio (100) / (002) is 0.04 or more.

  In FIG. 5, the iron plate 21 side is set to a positive potential and the conductor 11 side is set to a negative potential. Further, the voltage applied to the iron plates 21 and 22, that is, the potential of the iron plates 21 and 22 may be equipotential if the scale-like hexagonal boron nitride filler 121A in the filler layer 121 rises in the direction perpendicular to the film surface. They may be different from each other.

  As shown in FIGS. 1 and 5, the conductor 11 obtained by bundling a plurality of strands made of copper in two rows horizontally and eight rows vertically contains epoxy resin at 90% by volume. In addition, a filler layer containing a flaky hexagonal boron nitride filler (aspect ratio: 1 to 100), containing 10% by volume of epoxy resin, and containing a flaky mica filler (aspect ratio: 1 to 100) It was wound 10 times with an insulating tape comprising a mica layer and a backing layer formed by impregnating a glass cloth located between them with an epoxy resin.

After that, the assembly obtained as described above was put into a vacuum pressure tank and evacuated, and then polyethylene wax at 150 ° C. was poured, and polyethylene wax was used as a medium and a pressure of 7 kgf / cm ² was applied with nitrogen gas. It heated in the added state, the said epoxy resin was hardened, and the rotary electric stator as shown in FIG. 1 was manufactured.

  In the manufacturing process as described above, a voltage of 1 kV / mm to 10 kV / mm is applied between the iron plate for holding the assembly and the conductor, and the scaly hexagonal crystal in the filler layer in the insulating layer is applied. The orientation ratio (100) / (002) of the boron nitride filler was controlled.

  FIG. 6 is a graph showing the relationship between the orientation rate (100) / (002) of the hexagonal boron nitride filler in the filler layer and the thermal conductivity. As is clear from FIG. 6, the orientation rate (100) / (002) of the hexagonal boron nitride filler in the filler layer is 0.04 or more, so that the thermal conductivity of the filler layer is remarkably improved and the insulation is improved. It can be seen that the thermal conductivity of the layer can also be improved. Therefore, it can be seen that a rotating electrical machine stator having heat conduction characteristics that can sufficiently cope with an increase in the amount of heat generated in the conductor and sufficient insulation characteristics for the conductor can be provided.

  The present invention has been described in detail based on the above specific examples. However, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Rotating electrical machine stator 11 Conductor 111 Strand 12 Insulating layer 121 Filler layer 121A Scale-like hexagonal boron nitride filler 121B Resin 122 Mica layer 122A Mica filler 122B Resin 123 Backing layer 21 and 22 Iron plate

Claims (5)

A conductor formed by binding a plurality of strands;
An insulating layer having a filler layer and a mica layer containing a scaly hexagonal boron nitride filler having an orientation ratio (100) / (002) of 0.04 or more, which is formed so as to cover the outer peripheral surface of the conductor. When,
A rotating electric machine stator characterized by comprising:   The rotating electrical machine stator according to claim 1, wherein the insulating layer includes a backing material for the filler layer and the mica layer. A step of forming an insulating layer having a filler layer containing a non-oriented scale-like hexagonal boron nitride filler and a mica layer so as to cover an outer peripheral surface of a conductor formed by binding a plurality of strands;
Providing a metal fixing jig for fixing the insulating layer to the conductor;
A voltage is applied between the conductor and the fixing jig to generate a predetermined electric field in the thickness direction of the insulating layer, and the hexagonal boron nitride filler in the filler layer of the insulating layer is insulated from the insulating layer. Orienting in the thickness direction of the layer;
A method of manufacturing a rotating electric machine stator, comprising:   An insulating tape for a rotating electric machine stator comprising a filler layer containing a scale-like hexagonal boron nitride filler having an orientation ratio (100) / (002) of 0.04 or more and a mica layer.   The insulating tape for a rotating electric machine stator according to claim 7, further comprising a backing material for the filler layer and the mica layer.

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