JP2006109600A - Stator coil of rotating electric machine and its fixing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator coil of a rotating electric machine and its fixing method that surely fixes the stator coil, prevents a rise in the temperature of the stator coil caused by heat generated at a coil conductor, and prevents slot discharge between the stator coil and a stator core slot. <P>SOLUTION: The corona prevention layer 13 of the stator coil 10 is formed of resin 32 that is formed into a sheet shape and has rubber elasticity containing dispersed thermal expansion particles 33 that expand at a prescribed temperature. The corona prevention layer 13 is wound on an insulating layer 12 and fixed thereon. By this, since the side face of the stator coil 10 can be made to closely contact with the internal side face of the stator core slot 21, it is prevented that an air layer poor in thermal conductivity is formed between the side face of the stator coil 10 and the internal side face of the stator core slot 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a stator coil of a rotating electric machine such as a turbine generator and a fixing method thereof, and more particularly to a stator of a rotating electric machine in which a stator coil is inserted into a stator core slot and supported and fixed by a stator core. The present invention relates to a coil and its fixing method.

  In a rotating electrical machine such as a turbine generator, a stator coil inserted and inserted into a stator core slot of a stator core has a current flowing in the coil conductor itself and a slot in a magnetic flux using the stator core as a magnetic path. Due to the interaction with the component crossing the shaft, it vibrates by receiving an electromagnetic force twice the power frequency generated in the radial direction of the machine shaft. For this reason, a stator coil fixing method for suppressing this electromagnetic vibration is employed (for example, see Patent Document 1). An example of the fixing method using this conventional stator coil will be described with reference to FIG.

  As shown in FIG. 14, two stator coils 204 a having a rectangular cross section are formed so that the outer periphery of the coil conductor 201 is covered with a corona prevention layer 203 via an insulating layer 202 above and below the stator core slot 200 having a rectangular cross section. , 204b are stacked via the inter-coil spacer 205. The lower stator coil 204 b is disposed on the coil bottom spacer 206, and a lower wedge spacer 207 is installed on the upper stator coil 204 a, and the stator core is interposed via the lower wedge spacer 207. A wedge 208 is firmly driven into the opening of the slot 200. Further, as shown in FIG. 14, a semiconductive corrugated laminate 209 as shown in FIG. 15 is driven into the gap between the inner surface of the stator core slot 200 and the side surfaces of the stator coils 204a and 204b. Yes. In place of the corrugated laminate 209, a semiconductive flat laminate may be driven.

In such a rotating electrical machine, the inter-coil spacer 205, the coil bottom spacer 206, the spacer such as the under-wedge spacer 207, and the wedge 208 are used to connect the two stator coils 204 a and 204 b in the stator core slot 200. While fixing to a predetermined position in the vertical direction, both the stator coils 204a and 204b are pressed against the inner surface of the stator core slot 200 by the corrugated laminate 209, and the spring force and the frictional force of the pressure contact surface are used as described above. Vibration in the radial direction is suppressed, and slot discharge between the stator coils 204a and 204b and the stator core slot 200 is prevented.
JP-A-6-237549

  However, in the above-described conventional stator coil of a rotating electric machine and the fixing method thereof, an air layer having poor thermal conductivity is formed between the stator coils 204a and 204b and the inner surface of the stator core slot 200, and the stator. Heat dissipation in the iron core slot 200 is deteriorated, and the coil temperature during operation is prolonged and the organic material such as wedges and laminates are withered for a long period of time. . As a result, wear of the corona prevention layer 203 of the stator coils 204a and 204b proceeds, and slot discharge occurs between the stator coils 204a and 204b and the stator core slot 200, and the stator coils 204a and 204b are damaged. However, there were problems such as deterioration of insulation characteristics.

  Accordingly, the present invention has been made to solve the above-described problems, and the stator coil is securely fixed, the temperature of the stator coil is prevented from rising due to heat generated in the coil conductor, and the stator coil and the stator coil are fixed. It is an object of the present invention to provide a stator coil for a rotating electrical machine and a fixing method thereof for preventing slot discharge between core core slots.

  In order to achieve the above object, a stator coil of a rotating electrical machine according to the present invention includes an insulating layer formed on a wire bundle and a corona prevention layer formed on the insulating layer, and is provided on the stator core. In the stator coil of a rotating electrical machine fixed in the stator core slot thus formed, the corona prevention layer is formed by forming a sheet-like resin containing dispersed thermal expansion particles that expand at a predetermined temperature. It is characterized by.

  According to the stator coil of the rotating electrical machine, the corona prevention layer of the stator coil is configured by a sheet-like resin having rubber elasticity containing dispersed thermal expansion particles that expand at a predetermined temperature. Thus, the side surface of the stator coil can be brought into close contact with the inner side surface of the stator core slot, so that an air layer with poor thermal conductivity is formed between the side surface of the stator coil and the inner side surface of the stator core slot. The formation can be suppressed. As a result, the heat generated in the wire bundle can be efficiently conducted to the stator core and dissipated. Further, the stator coil can be firmly fixed in the stator core slot.

  Further, the stator coil of the rotating electric machine of the present invention includes an insulating layer formed on the wire bundle, and a corona prevention layer formed on the insulating layer, and a stator core slot provided on the stator core. In the stator coil of a rotating electrical machine fixed inside, the corona prevention layer is formed by laminating a semiconductive sheet having a surface resistance of 1Ω to 100 MΩ, and dispersing thermal expansion particles that expand at a predetermined temperature therebetween. It is characterized by interposing a resin sheet made of the contained resin.

  According to the stator coil of the rotating electric machine, the thermal expansion particles are thermally expanded by adopting a configuration in which the resin sheet made of resin containing the thermal expansion particles dispersed and contained is in close contact between the semiconductive sheets. As a result, the volume of the resin sheet increases and the volume of the entire corona prevention layer increases. By increasing the volume of the resin sheet, the corona prevention layer is brought into close contact with the side surface of the stator coil and the inner side surface of the stator core slot, and between the side surface of the stator coil and the inner side surface of the stator core slot. In addition, the formation of an air layer with poor thermal conductivity can be suppressed.

  Furthermore, the stator coil of the rotating electric machine according to the present invention includes an insulating layer formed on the wire bundle, and a corona prevention layer formed on the insulating layer, and the stator core slot provided in the stator core. In the stator coil of a rotating electrical machine fixed inside, the corona-preventing layer has a surface resistance of 1Ω to 100MΩ, and is a semiconductive sheet made of resin containing dispersed thermal expansion particles that expand at a predetermined temperature Is characterized in that a resin sheet is in close contact therewith.

  According to the stator coil of the rotating electrical machine, the semiconductive sheet is made of a resin containing dispersed thermal expansion particles, whereby the thermal expansion particles are thermally expanded and the volume of the semiconductive sheet is increased. And the volume of the whole corona prevention layer increases. By increasing the volume of the semiconductive sheet, the corona prevention layer is brought into close contact with the side surface of the stator coil and the inner side surface of the stator core slot, and the side surface of the stator coil and the inner side surface of the stator core slot are During this, it is possible to suppress the formation of an air layer with poor thermal conductivity.

  The stator coil fixing method of the rotating electrical machine according to the present invention is the stator coil fixing method of the rotating electrical machine in which the stator coil is fixed in the stator core slot provided in the stator core of the rotating electrical machine. A stator coil inserting step of inserting one or a plurality of stacked stator coils into the stator core slot, a wedge driving step of driving a wedge into an opening of the stator core slot, and at least the stator A heating step of heating the corona-preventing layer in the coil so that the temperature of the thermally expanded particles becomes a predetermined temperature at which the thermally expanded particles expand; and curing the resin containing the thermally expanded particles; And a resin curing step for tightly fixing in the stator core slot.

  According to the fixing method of the stator coil of the rotating electrical machine, the corona-preventing layer of the stator coil contains the thermal expansion particles that are expanded at a predetermined temperature. The side surface can be brought into close contact with the inner surface of the stator core slot, and the formation of an air layer with poor thermal conductivity between the side surface of the stator coil and the inner surface of the stator core slot is suppressed. Can do. As a result, the heat generated in the wire bundle can be efficiently conducted to the stator core and dissipated. Furthermore, the stator coil can be firmly fixed in the stator core slot by curing the resin containing the thermally expanded particles by the resin curing step.

  According to the stator coil and the fixing method of the rotating electrical machine of the present invention, the stator coil is securely fixed, the temperature of the stator coil is prevented from rising due to heat generated in the coil conductor, and the stator coil and the stator core Slot discharge between the slots can be prevented.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross-sectional view of the stator coil 10. FIG. 2 is a partial cross-sectional view of the rotating electrical machine in which the stator coils 10 a and 10 b are installed in the stator core slot 21 of the stator core 20.

  As shown in FIG. 1, the stator coil 10 is formed on a coil conductor 11 made of a wire bundle, an insulating layer 12 formed on the coil conductor 11, that is, on the outside, and an insulating layer 12, that is, on the outside. And a corona prevention layer 13.

  In addition, as shown in FIG. 2, the stator coil 10a and the stator coil 10b are installed on the bottom of the stator core slot 21 in a stacked state, and the side surfaces of the stator coils 10a and 10b are fixed to the stator. It is in close contact with the inner surface of the iron core slot 21. Further, a wedge 22 is driven into the opening of the stator core slot 21 with the bottom surface thereof being in close contact with the upper surface of the stator coil 10a, and the stator coil 10a is positioned at a predetermined position in the stator core slot 21 in the vertical direction. 10b is fixed.

  FIG. 2 shows an example in which two stacked stator coils 10 a and 10 b are fixed in the stator core slot 21, but one or three or more in the stator core slot 21. The stator coil may be fixed.

  Next, the configuration of the stator coil 10, particularly the configuration of the corona prevention layer 13, will be described in detail.

(First embodiment)
The stator coil 10 of 1st Embodiment is demonstrated with reference to FIGS.

  3 and 4 are sectional views of the corona prevention layer 13 containing the thermally expanded particles 33 dispersed therein.

  As shown in FIG. 3, the corona prevention layer 13 of the stator coil 10 shown in FIG. 1 is formed in a sheet shape with a resin 32 having rubber elasticity containing dispersed thermal expansion particles 33 that expand at a predetermined temperature. Composed of things. The corona prevention layer 13 is wound and fixed on the insulating layer 12.

  The thermal expansion particle 33 includes a liquid that evaporates at 40 to 150 ° C. in a hollow fine particle, for example, a microcapsule. As shown in FIG. 3, the thermally expanded particles 33 are formed so as to include a low-boiling liquid 31 that vaporizes at 40 to 150 ° C. in the hollow particles 30 having an average particle diameter of about 30 μm. The microcapsule is made of, for example, polyethylene and deforms following volume expansion due to vaporization of the liquid. As this thermal expansion particle 33, ADVANCEL EM (made by Sekisui Chemical) etc. can be used, for example. Further, instead of the thermally expanded particles 33, expandable particles that expand at a predetermined temperature or the like may be used. Here, the boiling point of the liquid is set to 40 to 150 ° C. When the boiling point is lower than 40 ° C., the microcapsule may swell before use and cannot be inserted into the stator core slot 21 of the stator coil 10. This is because when the temperature is higher than 150 ° C., other insulating members may be damaged when the microcapsules are expanded.

  The resin 32 having rubber elasticity is preferably a resin that has a viscosity at which the thermally expandable particles 33 can sufficiently expand at a temperature at which the thermally expandable particles 33 start to expand, and further gels when heated to a high temperature. Examples of the resin having such characteristics include silicone rubber TSE3331 (manufactured by Toshiba GE Silicone), ethylene propylene rubber, and the like.

  Here, instead of the resin 32 having rubber elasticity, for example, a semi-cured resin may be used. Examples of the semi-cured resin include, but are not limited to, an epoxy resin, a polyimide resin, a phenol resin, and a bismaleimide resin. Further, as the semi-cured resin, one having a gelling temperature higher than the temperature at which the thermally expandable particles 33 start to expand is selected. Furthermore, in addition to the resin 32 having rubber elasticity and the semi-cured resin, for example, a thermoplastic resin can be used. In the case of using a thermoplastic resin, a resin that is softened near and at a temperature lower than the temperature at which the thermally expandable particles 33 start to expand is selected.

  Next, with reference to FIGS. 3 and 4, the expansion process of the thermally expandable particles 33 in the resin 32 will be described.

  When the corona prevention layer 13 is heated and the liquid 31 in the hollow particles 30 reaches the boiling point, as shown in FIG. 4, the liquid 31 is vaporized to increase the volume, and the hollow particles 30 expand. At this time, the resin 32 containing the hollow particles 30 has such a viscosity that the thermally expandable particles 33 can be sufficiently expanded, and the volume of the corona prevention layer 13 as a whole increases as the hollow particles 30 expand. Thus, by increasing the volume of the entire corona prevention layer 13, the side surfaces of the stator coils 10a and 10b can be brought into close contact with the inner side surface of the stator core slot 21, as shown in FIG. It is possible to suppress the formation of an air layer with poor thermal conductivity between the side surfaces of the stator coils 10 a and 10 b and the inner side surface of the stator core slot 21.

  Here, the volume ratio of the thermal expansion particles 33 in the entire corona prevention layer 13 during the volume expansion of the thermal expansion particles 33 is 5% or more and 30% or less, although there is an entanglement with the dimensional accuracy of the stator coil 10. It is preferable. It is preferable to set the volume ratio of the thermal expansion particles 33 within this range. When the volume ratio is smaller than 5%, the gap between the stator coil 10 and the stator core slot 21 is sufficiently filled. This is because if the volume ratio is larger than 30%, the heat insulating property is increased. Further, when the volume ratio is larger than 30%, the expanded thermal expansion particles 33 are connected, and the strength of the corona prevention layer 13 may be lowered. The average particle diameter of the thermal expansion particles 33 is not limited to about 30 μm as described above, and the expansion coefficient and thermal expansion of the thermal expansion particles 33 are within a range that satisfies the volume ratio at the time of volume expansion of the thermal expansion particles 33. It can also be changed after taking the content of the particles 33 into account.

  The maximum value (30%) of the volume ratio setting range is a value determined based on the percolation theory, and is based on the following theory.

  FIG. 5 shows the relationship between the volume ratio when the particles are dispersed in the space and the size of the clusters formed by the particles in that case. As shown in FIG. 5, when particles reach a certain volume (percolation threshold) or more, the particles are connected through the space, and the size of the cluster diverges to infinity. The part where particles are connected through space is called a percolation path, and the number of percolation paths increases exponentially when the percolation threshold is exceeded. Since the strength of the microcapsules of the thermally expanded particles 33 is low, when the percolation path increases, the strength of the corona prevention layer 13 is reduced. Further, according to the percolation theory, the volume ratio in which randomly arranged mass points form an infinite cluster is about 30% in three dimensions. Therefore, the maximum value of the volume ratio setting range is set to 30%.

  Next, a method of fixing the stator coil 10 of the rotating electrical machine of the first embodiment to the stator core slot 21 will be described with reference to FIG. Here, a case where two stacked stator coils 10a and 10b are fixed will be described as an example.

  First, the side surfaces of the stacked stator coils 10 a and 10 b are inserted from the opening of the stator core slot 12 while being in sliding contact with the inner side surface of the stator core slot 21, and are placed on the bottom surface of the stator core slot 21. Install.

  Subsequently, the bottom surface of the wedge 22 is brought into close contact with the upper surface of the stator coil 10 a, and the wedge 19 is driven into the opening of the stator core slot 21. Thereby, the stator coils 10a and 10b are fixed at predetermined positions in the stator core slot 21 in the vertical direction.

  Subsequently, for example, the surface of the stator core 20, the stator coils 10a and 10b, the coil conductor 11 or the like so that the temperature of the thermal expansion particles 33 of the corona prevention layer 13 becomes a predetermined temperature at which the thermal expansion particles expand. Heat. As a result, as described above, the thermally expandable particles 33 expand and the volume of the entire corona prevention layer 13 increases. By increasing the volume of the entire corona prevention layer 13 in this way, the side surfaces of the stator coils 10a and 10b can be brought into close contact with the inner surface of the stator core slot 21, and the side surfaces of the stator coils 10a and 10b It is possible to suppress the formation of an air layer with poor thermal conductivity between the inner surface of the stator core slot 21. During the expansion process of the thermally expanded particles 33, the temperature of the thermally expanded particles 33 is maintained at a predetermined temperature at which the thermally expanded particles expand.

  After the expansion step of the thermally expandable particles 33 is completed, the temperature of the corona prevention layer 13 is increased to a temperature at which the resin 32 gels to cure the resin 32. As a result, the stator coils 10 a and 10 b can be firmly fixed in the stator core slot 21.

  As described above, according to the stator coil 10 of the first embodiment, the resin 32 containing the corona-preventing layer 13 of the stator coil 10 dispersedly containing the thermal expansion particles 33 that expand at a predetermined temperature. By constituting with a sheet shape, the side surface of the stator coil 10 can be brought into close contact with the inner surface of the stator core slot 21, and the side surface of the stator coil 10 and the inner surface of the stator core slot 21 During this, it is possible to suppress the formation of an air layer with poor thermal conductivity. Thereby, the heat generated in the coil conductor 11 can be efficiently conducted to the stator core 20 and radiated. Furthermore, the stator coil 10 can be firmly fixed in the stator core slot 21.

  Next, a specific example in which the corona prevention layer 13 is produced and the stator coil 10 provided with the corona prevention layer 13 is fixed to the stator core slot 21 will be described.

Example 1
First, a liquid A was prepared by kneading 15 phr of microcapsules containing a low boiling point liquid (low boiling point hydrocarbon) having an average particle diameter of 15 μm with a silicone resin. Subsequently, platinum solution as a catalyst was kneaded with solution A for 1 phr to prepare solution B.

  Subsequently, the liquid B was formed into a sheet having a thickness of about 0.5 mm and a width of 300 mm using a roll coater. Further, this sheet was passed through a slitter to produce a tape having a width of 50 mm. And, on the outer periphery of the bar model coil produced by winding mica tape around the outer periphery of the coil conductor made of 20 mm × 50 mm aluminum bar and impregnating and curing, the above manufactured tape is not overlapped with each other. It was wound with a gap of about 3 mm. In addition, the thickness of the insulating layer of this bar model coil is 3 mm.

  Further, as shown in FIG. 2, the bar model coil is inserted into a stator core slot having a width of 27.5 mm and a depth of 57 mm, and a wedge 19 is driven into the opening of the stator coil 10 to obtain about 120 ° C. Heated with. At this time, the volume expansion coefficient of the microcapsule was 200%.

  As a result, the apparent volume of the silicone resin increased, and the space between the stator core and the stator coil could be filled closely. The gel time of the silicone resin was at least 1 day at 120 ° C. This is because if the silicone resin is hardened quickly, the microcapsule is hardened before expansion, and the microcapsule cannot sufficiently expand in volume.

(Second Embodiment)
A stator coil 10 according to a second embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as the structure of the stator coil 10 of 1st Embodiment, and the description is simplified or abbreviate | omitted.

  In FIG. 6, sectional drawing of the corona prevention layer 13 which disperse | distributed and contained the thermal expansion particle 33 and the electroconductive particle 40 is shown.

  As shown in FIG. 6, the corona prevention layer 13 of the stator coil 10 shown in FIG. 1 includes a rubber-elastic resin 32 containing conductive particles 40 and thermally expanded particles 33 that expand at a predetermined temperature. It consists of what was formed in the sheet form. The surface resistance of the corona prevention layer 13 is 1Ω to 100MΩ. The corona prevention layer 13 is wound and fixed on the insulating layer 12. As in the case of the first embodiment, for example, a semi-cured resin or a thermoplastic resin may be used instead of the resin 32 having rubber elasticity.

  The conductive particles 40 are made of, for example, a metal such as copper, iron, or aluminum, carbon, carbon black, iron trioxide, etc., for example, Kishida Chemical's iron trioxide, Mitsubishi Chemical's acetylene black, or the like. Is used. Moreover, the content rate of the electroconductive particle 40 in the resin 32 is set so that the surface resistance of the corona prevention layer 13 may be 1Ω to 100 MΩ. In addition, the measurement of surface resistance is measured by the 2 Mizuko, the 3 terminal method, the 4 terminal method, etc.

  Here, generally, when a voltage is applied to the stator coil 10, a high voltage is generated on the surface of the insulating layer 12 of the stator coil 10, and a discharge is generated between the stator core 20 that is the ground potential and the surface of the insulating layer 12. Occurs. For this reason, it is well known to use a semiconductive tape or paint on the surface of the insulating layer 12, which is called a low resistance corona prevention layer (corresponding to the corona prevention layer 13 of the present invention). If the surface resistivity of the low resistance corona prevention layer is less than 1Ω, an eddy current is generated in the low resistance corona prevention layer, which is not preferable. Further, when the surface resistivity is greater than 100 MΩ, sufficient corona prevention ability cannot be exhibited. Therefore, the surface resistance of the corona prevention layer 13 was adjusted to 1Ω to 100MΩ.

  As described above, when the structure containing the conductive particles 40 is used in the corona prevention layer 13, the stability of the surface resistivity leads to the stability of the corona prevention ability, and thus the surface resistivity has a stable characteristic. It becomes important.

  As is apparent from the relationship between the volume ratio of the conductive particles 40 in the corona prevention layer 13 and the surface resistivity shown in FIG. 7, these relationships are drawn by a curve having two bending points. Is generally known.

  In the case of the corona prevention layer 13 in the second embodiment, a so-called two-particle composite in which the thermally expanded particles 33 and the conductive particles 40 are added to the resin 32 is formed. The conductive properties of such a two-particle composite were determined by the inventors, for example, by Tetsushi Okamoto et al., P83-p86 (Percolation phenomena of field) of Proceedings of 2001 International Symposium on Electrical Insulating Materials (2001). This can be explained by the percolation theory of a two-particle composite disclosed in “grading materials made of two kinds of filler”.

FIG. 8 shows volume resistivity when boron nitride (HP-1CAW made by Mizushima Alloy Iron) and carbon black (Asahi Thermal made by Asahi Carbon) are added to isopropylene elastomer (Kuraray Septon 2007) which is a thermoplastic elastic body. Shows changes.
Here, in FIG. 8, the horizontal axis represents the volume ratio (P) of carbon black in the entire volume excluding boron nitride. The vertical axis indicates volume resistivity (ρ) and is logarithmically displayed.

We, the volume resistivity of the two-particle composite body, as the second reference bending point P _C (high filling side) revealed that represented by the following formula (1).
ρ = (P−P _C ) ⁻² Formula (1)

And if Formula (1) takes a logarithm on both sides and changes, it will become the following Formula (2).
logρ / log (P−P _C ) = − 2 Equation (2)

Then, stable in order to obtain the volume resistivity, determined the P _C so as to satisfy the relationship of formula (2), containing carbon black as a conductive particle such that the P _C value or more volume ratio It is necessary to determine the amount.

Further, instead of the boron nitride, the volume ratio of even the conductive particles in the case of the configuration of the present invention using a thermal expansion particles 33 With P _C values above, the volume resistivity stability, i.e. the conductive properties stable Can be achieved.

  As described above, according to the stator coil 10 of the second embodiment, in addition to the effects obtained by containing the thermally expandable particles 33 in the corona prevention layer 13 in the first embodiment, In addition, by containing the conductive particles 40 in the corona prevention layer 13 and setting the surface resistance to 1Ω to 100MΩ, high thermal conductivity and corona discharge prevention capability can be obtained.

(Third embodiment)
A stator coil 10 according to a third embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as the structure of the stator coil 10 of 1st or 2nd embodiment, and the description is simplified or abbreviate | omitted.

  FIG. 9 shows a cross-sectional view of the corona prevention layer 13 containing the thermally expanded particles 33 and the thermally conductive filler 50 dispersed therein.

  As shown in FIG. 9, the corona prevention layer 13 of the stator coil 10 shown in FIG. 1 is a resin having rubber elasticity containing a thermally conductive filler 50 and thermally expanded particles 33 that expand at a predetermined temperature. 32 is formed in a sheet shape. The corona prevention layer 13 is wound and fixed on the insulating layer 12. As in the case of the first embodiment, for example, a semi-cured resin or a thermoplastic resin may be used instead of the resin 32 having rubber elasticity.

  The thermally conductive filler 50 is composed of particles made of a material having a thermal conductivity of 1 W / (m · K) or more. Examples of the material having a thermal conductivity of 1 W / (m · K) or more include carbon, alumina, silicon nitride, aluminum nitride, magnesium oxide, boron nitride, aluminum oxide, silicon oxide, and liquid crystal epoxy. Here, the reason why the thermal conductivity of the thermally conductive filler 50 is set to 1 W / (m · K) or more is that if a filler of less than 1 W / (m · K) is used, the thermal conductivity cannot be improved. .

  Among the materials of the above-described thermally conductive filler 50, boron nitride, silicon oxide, and liquid crystal epoxy are particularly preferably used as the thermally conductive filler 50 for the following reasons.

  In the corona prevention layer 13 disposed between the stator coil 10 and the stator core slot 12, a gap is generated between the stator coil 10 and the stator core slot 12 when sufficient conductivity is not ensured. When this happens, a potential is generated. At this time, if the dielectric constant of the corona prevention layer 13 is high, the electric field applied to the gap is high, and a discharge is likely to occur. However, since boron nitride, silicon oxide, and liquid crystal epoxy have a lower dielectric constant than other heat conductive fillers 50, the electric field in the gap increases even when the above-described conductivity is not sufficiently ensured. Difficult and has excellent electrical insulation ability. Therefore, it is particularly preferable to use boron nitride, silicon oxide, or liquid crystal epoxy as the heat conductive filler 50.

  Moreover, it is preferable that the average particle diameter of the particle | grains of the heat conductive filler 50 shall be 0.2 micrometer-500 micrometers. The reason why the average particle size is set in this range is that when the average particle size is smaller than 0.2 μm, a sufficient improvement in thermal conductivity cannot be expected. This is because the stator coil 10 becomes thicker and the stator coil 10 cannot be inserted into the stator core slot 21.

  Moreover, the content rate of the heat conductive filler 50 contained in the resin 32 is contained so that the heat conductivity of the entire corona prevention layer 13 is 0.2 W / (m · K) or more. This is because a thermal conductivity lower than that cannot contribute to a sufficient improvement in cooling performance.

  Further, the heat conductive filler 50 may be composed of two types of heat conductive particles as disclosed in Japanese Patent Application Laid-Open No. 2004-35782. Examples of these two types of thermally conductive particles include particles having a thermal conductivity of 10 W / (m · K) or higher and particles having a thermal conductivity of 0.5 W / (m · K) or higher. Examples of the material having a thermal conductivity of 10 W / (m · K) or more include boron nitride, alumina, silicon nitride, aluminum nitride, and carbon, and a thermal conductivity of 0.5 W / (m · K) or more. Examples of the material having carbon include carbon and alumina. Here, the mixture of particles having a thermal conductivity of 10 W / (m · K) or more and particles having a thermal conductivity of 0.5 W / (m · K) or more provides excellent thermal conductivity. Because it can.

  Further, the particles having a thermal conductivity of 0.5 W / (m · K) or more are in a ratio of 1% to 30% with respect to the volume sum of the resin 32 and the particles of 0.5 W / (m · K). It is preferable to mix them together. The ratio of particles having a thermal conductivity of 0.5 W / (m · K) or more to 1% or more and 30% or less with respect to the volume sum of the resin 32 and 0.5 W / (m · K) particles. If less than 1%, excellent thermal conductivity cannot be obtained, and if greater than 30%, the particle spacing of particles having a thermal conductivity of 10 W / (m · K) or more is large. This is because excellent thermal conductivity cannot be obtained. The thermal conductivity can be measured by, for example, a laser flash method.

  Here, the above-described corona prevention layer 13 includes a case where the thermal conductive filler 50 is further dispersed and contained in the corona prevention layer 13 containing the thermally expanded particles 33 of the first embodiment dispersed therein. Although shown, the heat conductive filler 50 may be further dispersed and contained in the corona prevention layer 13 containing the thermally expanded particles 33 and the conductive particles 40 of the second embodiment.

  As described above, according to the stator coil 10 of the third embodiment, in addition to the effects obtained by including the thermally expandable particles 33 in the corona prevention layer 13 in the first embodiment, Since the corona prevention layer 13 has a high thermal conductivity, heat from the stator coil 10 can be efficiently conducted to the stator core 20, and excellent cooling characteristics of the stator coil 10 can be obtained. .

  Moreover, according to the stator coil 10 of the third embodiment, in addition to the effect obtained by including the conductive particles 40 in the corona prevention layer 13 of the second embodiment, the corona prevention layer is further provided. Since 13 has a high thermal conductivity, heat from the stator coil 10 can be efficiently conducted to the stator core 20, and excellent cooling characteristics of the stator coil 10 can be obtained.

  Next, the heat conductivity when the thermally conductive filler 50 is configured with the above-described two types of thermally conductive particles and the case where the thermally conductive filler 50 is configured with one type of thermally conductive particles The specific example which compared thermal conductivity is shown.

(Example 2)
In Example 2, the first sample and the second sample are prepared, and the thermal conductivity in the case where the thermal conductive filler 50 is configured with two types of thermal conductive particles, and one type of thermal conductivity. The thermal conductivity when the thermally conductive filler 50 is composed of particles was compared.

  In the first sample, 60% by volume of boron nitride (HP-1CAW made of Mizushima Alloy Iron) having an average particle diameter of 16 μm having a thermal conductivity of 10 W / (m · K) or more is dispersed in an isopropylene-based polymer, and then It was produced by press-curing with a press so that the length was 100 mm, the width was 100 mm, and the thickness was 0.3 mm.

The second sample has a volume ratio of 0.5 W / for 60% by volume of boron nitride (HP-1CAW made of Mizushima alloy iron) having a thermal conductivity of 10 W / (m · K) or more and an average particle diameter of 16 μm. 15% by volume of alumina having a thermal conductivity of (m · K) or more and an average particle size of 70 nm (NanoTekHTAl ₂ O ₃ manufactured by CI Kasei) is uniformly stirred with a stirrer and dispersed in an isopropylene polymer. The volume ratio of boron nitride and alumina is adjusted to 64% by volume, and then press cured by a press machine so that the length is 100 mm, the width is 100 mm, and the thickness is 0.3 mm. It was made.

  And about the above-mentioned 1st sample and 2nd sample, the thermal conductivity was measured using the laser flash method.

  FIG. 10 shows the measurement results, showing the relationship between the volume ratio of alumina and the thermal conductivity. The volume ratio of alumina on the horizontal axis is the volume ratio of alumina in the resin containing alumina.

  As is apparent from FIG. 10, when the alumina particles are added, the thermal conductivity is higher than when the particles are not added. This is presumably because the alumina particles entered the isopropylene polymer content of the material filled with boron nitride and supplemented the thermal conductivity between the boron nitrides.

  From this result, it was found that the thermal conductivity can be improved by a factor of 2 or more by adding a little alumina as compared with a sample made only of boron nitride.

  Further, FIG. 11 shows the relationship between the volume ratio of carbon black and the thermal conductivity when carbon black particles (Asahi Thermal manufactured by Asahi Carbon Co., Ltd.) having an average particle diameter of 90 nm are used instead of the alumina particles described above. . The volume ratio of carbon black on the horizontal axis is the volume ratio of carbon black in the resin containing carbon black.

  As is apparent from FIG. 11, as in the case of alumina, when carbon black particles are added, the value of thermal conductivity is higher than when no carbon black particles are added. Also in this case, it was found that carbon black functions in the same manner as the above-described alumina, and the same effect as when alumina is added can be obtained. In addition, when carbon black is used, high thermal conductivity can be obtained and conductivity can be improved.

(Fourth embodiment)
A stator coil 10 according to a fourth embodiment will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the component same as the structure of the stator coil 10 of 1st-3rd embodiment, and the description is simplified or abbreviate | omitted.

  FIG. 12 shows a cross-sectional view of the corona prevention layer 13 in which the resin sheet 63 containing the thermally expanded particles 33 dispersed therein is interposed between the semiconductive sheets.

  As shown in FIG. 12, the corona prevention layer 13 of the stator coil 10 shown in FIG. 1 closely contacts a resin sheet 63 made of a resin 32 containing dispersed thermal expansion particles 33 between the semiconductive sheets 60. It is formed by interposing.

  For the semiconductive sheet 60, a nonwoven fabric made of, for example, polyethylene adjusted to have a surface resistivity of 1Ω to 100MΩ is used. The nonwoven fabric may be folded, for example, to form upper and lower semiconductive sheets 60 as shown in FIG. Moreover, you may form the upper and lower semiconductive sheets 60 as shown in FIG. 12 using two nonwoven fabrics. Furthermore, for example, a semiconductive material may be applied to the front and back surfaces of the resin sheet 63 together with a binder or the like, and the surface resistivity may be adjusted to be 1Ω to 100MΩ. Alternatively, the semiconductive sheet 60 may be formed in a tube shape having a predetermined shape, and the material constituting the resin sheet 63 may be filled therein. The semiconductive sheet 60 is not limited to a non-woven fabric but may be a woven fabric made of polyester, for example. Further, the resin sheet 63 may contain the heat conductive filler 50 described in the third embodiment.

  In addition, the resin sheet 63 is configured by forming a resin 32 containing the thermally expanded particles 33 dispersed therein into a sheet shape. The resin 32 further includes the thermal conductivity described in the third embodiment. The resin sheet 63 may be formed by containing the filler 50.

  According to the stator coil 10 of the fourth embodiment, the resin sheet 63 made of the resin 32 containing the thermally expanded particles 33 dispersed between the semiconductive sheets 60 is closely interposed. Thus, the thermally expanded particles 33 are thermally expanded, the volume of the resin sheet 63 is increased, and the volume of the entire corona prevention layer 13 is increased. By increasing the volume of the resin sheet 63, the corona prevention layer 13 is brought into close contact with the side surface of the stator coil 10 and the inner surface of the stator core slot 21, and the side surface of the stator coil 10 and the stator core slot 21. It is possible to suppress the formation of an air layer with poor thermal conductivity between the inner surface and the inner surface. Further, when the resin sheet 63 is formed by containing the heat conductive filler 50 in the resin 32, the heat from the stator coil 10 can be more efficiently conducted to the stator core 20, Excellent cooling characteristics of the stator coil 10 can be obtained.

  Moreover, the structure of the corona prevention layer 13 is not restricted to the structure shown in FIG. 12, For example, the structure shown in FIG. 13 can also be taken.

  FIG. 13 shows a cross-sectional view of the corona prevention layer 13 in which the resin sheet 71 is interposed between the semiconductive sheets 70 containing the thermally expanded particles 33 dispersed therein.

  The semiconductive sheet 70 is formed by forming the resin 32 containing the thermally expanded particles 33 in a sheet shape, and the surface resistivity is adjusted to be 1Ω to 100 MΩ. This sheet may be folded, for example, to form upper and lower semiconductive sheets 70 as shown in FIG. Moreover, you may form the upper and lower semiconductive sheets 70 as shown in FIG. 13 using two sheets. Furthermore, for example, the resin 32 containing the thermally expanded particles 33 dispersed therein may be applied to the front and back surfaces of the resin sheet 71. Alternatively, the semiconductive sheet 70 may be formed in a tube shape having a predetermined shape, and the material constituting the resin sheet 71 may be filled therein. Here, as a method for adjusting the surface resistivity, for example, the resin 32 may contain the conductive particles 40 described in the second embodiment.

  The resin sheet 71 is configured by forming the resin 32 containing the thermally conductive filler 50 described in the third embodiment in a sheet shape in a dispersed manner. The resin sheet 71 is disposed between the semiconductive sheets 70 in close contact with the semiconductive sheet 70.

  According to the stator coil 10, the semiconductive sheet 70 is composed of the resin 32 containing the thermally expanded particles 33 dispersed therein, whereby the thermally expanded particles 33 are thermally expanded, and the semiconductive sheet 70 The volume increases, and the volume of the entire corona prevention layer 13 increases. By increasing the volume of the semiconductive sheet 70, the corona prevention layer 13 is brought into intimate contact with the side surface of the stator coil 10 and the inner side surface of the stator core slot 21, and the side surface of the stator coil 10 and the stator core. It is possible to suppress the formation of an air layer with poor thermal conductivity between the inner surface of the slot 21. Further, by forming the resin sheet 71 by containing the heat conductive filler 50 in the resin 32, the heat from the stator coil 10 can be more efficiently conducted to the stator core 20 and fixed. Excellent cooling characteristics of the child coil 10 can be obtained.

Sectional drawing of the stator coil of this invention. Sectional drawing which shows a part of stator core of this invention. Sectional drawing of the corona prevention layer in the stator coil of 1st Embodiment. Sectional drawing of the corona prevention layer in the stator coil of 1st Embodiment. The figure which shows the relationship between the volume ratio of particle | grains, and the size of a cluster. Sectional drawing of the corona prevention layer in the stator coil of 2nd Embodiment. The figure which shows the relationship between the volume ratio of the electroconductive particle 40, and volume resistivity. The figure which shows the relationship between the volume ratio and volume resistivity of carbon black. Sectional drawing of the corona prevention layer in the stator coil of 3rd Embodiment. The figure which shows the relationship between the volume ratio of an alumina, and heat conductivity. The figure which shows the relationship between the volume ratio of carbon black, and thermal conductivity. Sectional drawing of the corona prevention layer in the stator coil of 4th Embodiment. Sectional drawing of the corona prevention layer in the other stator coil of 4th Embodiment. Sectional drawing which shows a part of conventional stator iron core. . Sectional drawing of the conventional corrugated laminated board.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 10a, 10b ... Stator coil, 11 ... Coil conductor, 12 ... Insulating layer, 13 ... Corona prevention layer, 30 ... Hollow particle, 31 ... Liquid, 32 ... Resin, 33 ... Thermal expansion particle.

Claims (15)

In a stator coil of a rotating electrical machine, comprising an insulating layer formed on a wire bundle, and a corona prevention layer formed on the insulating layer, and fixed in a stator core slot provided in the stator core,
The corona-preventing layer is a stator coil for a rotating electric machine, wherein a resin containing a dispersion of thermally expanded particles that expand at a predetermined temperature is formed into a sheet shape.   The stator coil for a rotating electric machine according to claim 1, wherein the thermally expanded particles include a liquid that vaporizes at 40 to 150 ° C in hollow fine particles.   The stator coil of a rotating electrical machine according to claim 1 or 2, wherein the corona prevention layer contains conductive particles made of a conductive material in a dispersed manner and has a surface resistance of 1Ω to 100MΩ. When the volume ratio of the conductive particles in the resin containing the conductive particles is P and the volume resistivity is ρ,
logρ / log (P−P _C ) = − 2
Defining a P _C so as to satisfy the relationship, the stator coil of the rotating electric machine according to claim 3, wherein the content of the conductive particles such that the P _C value over the volume ratio is determined .   The stator coil for a rotating electrical machine according to any one of claims 1 to 4, wherein the corona-preventing layer contains a thermally conductive filler having a thermal conductivity of 1 W / (m · K) or more. .   The corona prevention layer includes a first thermal conductive filler having a thermal conductivity of 10 W / (m · K) or more and a second thermal conductivity having a thermal conductivity of 0.5 W / (m · K) or more. The stator coil for a rotating electric machine according to any one of claims 1 to 4, further comprising a filler. In a stator coil of a rotating electrical machine, comprising an insulating layer formed on a wire bundle, and a corona prevention layer formed on the insulating layer, and fixed in a stator core slot provided in the stator core,
The corona-preventing layer is formed by laminating a semiconductive sheet having a surface resistance of 1Ω to 100MΩ, and interposing a resin sheet made of a resin containing dispersed thermal expansion particles expanding at a predetermined temperature. A stator coil for a rotating electrical machine. In a stator coil of a rotating electrical machine, comprising an insulating layer formed on a strand of wire, and a corona prevention layer formed on the insulating layer, and fixed in a stator core slot provided in the stator core,
The corona-preventing layer has a surface resistance of 1Ω to 100MΩ, and is formed by laminating a semiconductive sheet made of a resin containing dispersed thermal expansion particles that expand at a predetermined temperature, and the resin sheet is in close contact therewith. A stator coil for a rotating electrical machine.   The stator coil for a rotating electrical machine according to claim 7 or 8, wherein the resin sheet contains a thermally conductive filler having a thermal conductivity of 1 W / (m · K) or more.   The resin sheet has a first thermal conductive filler having a thermal conductivity of 10 W / (m · K) or more and a second thermal conductive filling having a thermal conductivity of 0.5 W / (m · K) or more. The stator coil for a rotating electric machine according to claim 7 or 8, characterized by containing a material.   9. The rotating electrical machine according to claim 1, wherein a volume ratio of the thermal expansion particles in the corona prevention layer is 5 to 30% during expansion of the thermal expansion particles. Stator coil.   The stator coil of a rotating electrical machine according to claim 1, wherein the resin is made of a resin having rubber elasticity.   The stator coil of a rotating electric machine according to any one of claims 1 to 11, wherein the resin is made of a semi-cured resin.   The stator coil of a rotating electrical machine according to any one of claims 1 to 11, wherein the resin is made of a thermoplastic resin that softens at a temperature at which the thermally expandable particles expand. In the fixing method of the stator coil of the rotary electric machine which fixes the stator coil of any one of Claims 1 thru | or 14 in the stator core slot provided in the stator iron core of the rotary electric machine,
A stator coil insertion step of inserting one or a plurality of stacked stator coils into the stator core slot;
A wedge driving step of driving a wedge into the opening of the stator core slot;
At least a heating step of heating the temperature of the thermally expanded particles of the corona-preventing layer in the stator coil so as to be a predetermined temperature at which the thermally expanded particles expand;
A method of fixing a stator coil of a rotating electrical machine, comprising: a resin curing step of curing the resin containing the thermally expanded particles and closely fixing the stator coil in the stator core slot.

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