JP2010158113A - Electrical insulating member, stator coil for rotating electrical machine, and rotating electrical machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrical insulating member, capable of exhibiting superior electrical insulation performance and high thermal conductivity, even under a high-humidity environment, and to provide a stator coil for a rotating electrical machine, and to provide a rotating electrical machine. <P>SOLUTION: The electrical insulating tape 20 includes a reinforcing base material 22; a low relative dielectric constant heat transfer layer 23, formed on one surface of the reinforcing base material 22; and a mica layer 21, formed on the other surface of the reinforcing base material. The low relative dielectric constant heat transfer layer 23 has relative dielectric constant of ≤4 in 50-60 Hz measured frequency, thermal conductivity of ≥2 W/(m K) in the thickness direction, and thermal conductivity of ≥0.35 W/(m K) in the thickness direction of the electrical insulating member as a whole. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention includes an electrical insulating member wound around a coil conductor bundle of a rotating electrical machine such as a water turbine generator or a turbine generator, a stator coil for a rotating electrical machine around which the electrical insulating member is wound, and the stator coil. It relates to a rotating electrical machine.

  In a rotating electrical machine such as a turbine generator or a turbine generator, a stator coil inserted in a stator slot of a stator core has a current flowing through the coil conductor itself and a magnetic flux that uses the stator core as a magnetic path. Due to the interaction with the component crossing the inner stator slot, it vibrates by receiving an electromagnetic force twice the power frequency generated in the radial direction of the machine shaft. In a rotating electrical machine, Joule heat is generated by a large current flowing through a coil conductor bundle during operation.

  FIG. 6 is a view schematically showing a cross section of a conventional stator core 300 in which the stator coil 302 is accommodated in the stator slot 301.

  As shown in FIG. 6, a stator coil 302 is disposed in a stator slot 301 having a rectangular cross section formed in the stator core 300. The stator coil 302 mainly includes a coil conductor bundle 303 and an electric insulating layer 304 formed on the outer peripheral surface of the coil conductor bundle 303. In addition, a spacer 305 is disposed to prevent the stator coil 302 from moving in the vertical direction, and a spacer member 306 is disposed to prevent the stator coil 302 from moving in the lateral direction, and are fixed by a wedge 307.

  As described above, Joule heat is generated in the coil conductor bundle 303, and this Joule heat is transmitted to the stator core 300 through the electrical insulating layer 304 formed on the outer peripheral surface of the coil conductor bundle 303. On the other hand, electrical insulation between the coil conductor bundle 303 and the stator core 300 is maintained by the electrical insulation layer 304. As described above, the electrical insulation layer 304 is required to have electrical insulation characteristics and excellent thermal conductivity.

  In order to achieve both of these requirements, electrical insulation properties that can withstand high voltages and high thermal conductivity, a high thermal conductivity filler layer containing a filler with high thermal conductivity is added to the mica insulation layer with excellent electrical insulation properties. A technique is disclosed in which an insulating layer is formed by winding a laminated insulating tape around a coil conductor bundle (see, for example, Patent Document 1).

In addition, insulation in the stator coils of generators and motors is subject to electrical, mechanical, and thermal stresses during operation of the equipment depending on various usage environments of the equipment. For example, it has been reported that the corona-preventing layer on the surface of the electrical insulating layer deteriorates due to stress applied to the stator coil (see, for example, Non-Patent Document 1). This report is an accelerated test for simulating a real machine, but it is thought that the same phenomenon occurs in the real machine environment. In the portion where the corona prevention layer has deteriorated, the deterioration of the mica insulating layer is accelerated by the induction of partial discharge and the exposure of the surface of the mica insulating layer. Therefore, in the insulation design of the actual machine, the mica insulation layer is designed with a sufficient margin against the electric, thermal, and mechanical stress applied during the operation of the equipment. However, due to various external factors, the mica insulating layer may be deteriorated as described above.
JP-A-11-250737 IEEE Transactions on energy conversion, vol.19, No.4 p710

  Even in the electrical insulation layer having the mica insulation layer and the high thermal conductive filler layer as described above, it is sufficiently expected that the deterioration occurs as described above during the operation of the device. In this case, there is a possibility that a new problem as shown below may occur as compared with a conventional electric insulating layer that does not include a high thermal conductive filler layer and is formed of a mica insulating layer.

  In the conventional electrical insulating layer having the above-described mica insulating layer and high thermal conductive filler layer, the high thermal conductive filler layer mainly contributes to improving the high voltage insulation characteristics in order to improve the thermal conductivity of the entire insulating layer. For this reason, the mica insulating layer contributes mainly. In any case, in order to further improve the thermal conductivity, it is effective to increase the proportion of the filler in the high thermal conductive filler layer. However, in the conventional technique, an increase in the filling rate is not preferable for improving the electrical insulation characteristics.

  That is, an inorganic material called a filler is mainly used as the filler in the high thermal conductive filler layer, but when the filler filling amount is increased, the relative dielectric constant of the high thermal conductive filler layer is increased. This is because the relative dielectric constant of aluminum oxide, which is a typical inorganic filler used, is about 8, compared to the relative dielectric constant (about 3 to 4) of an epoxy resin mainly used as an adhesive resin. Because it is expensive. The dielectric constant of the composite material when the adhesive resin and filler are mixed can be verified by the Nielsen equation. For example, the inventors have studied that the dielectric constant when the epoxy resin adhesive is filled with 50% or more of aluminum oxide by volume fraction is about 5.2. In the Nielsen equation described above, the relative dielectric constant of the composite increases as the volume filling factor of the filler increases. In order to improve heat dissipation, the volume fraction of the filler must be increased to improve the thermal conductivity of the high thermal conductive filler layer, while the relative dielectric constant of the high thermal conductive filler layer increases.

  In the insulation of a rotating electrical machine, such an increase in the relative dielectric constant of the high thermal conductive filler layer may not be preferable. In the case of a turbine generator or an electric motor, the humidity of the surface of the stator coil is close to the humidity of the use environment atmosphere. In a hydroelectric power plant, water may flow into the power plant due to heavy rain and the water turbine generator may be exposed to a high humidity environment. In addition to such a situation, when the corona prevention layer is deteriorated during the above-described operation, the surface of the high thermal conductive filler layer is exposed to a high humidity environment, and the electrical insulation characteristics are deteriorated. In the state where the surface of the high thermal conductive filler layer is exposed to a high humidity environment, it is considered that the moisture on the surface, that is, the adhesion of water molecules, affects the electrical insulation characteristics.

  In general, the wettability of water is an example of an index indicating adhesion. As a method for controlling the wettability of the surface, it is common to perform a surface treatment such as applying a material with low wettability to the surface. However, in an environment where the corona-preventing layer is deteriorated, the surface treatment component may be deteriorated due to corona discharge or the like. That is, the wettability of the material of the high thermal conductive filler layer is important. The wettability of a material with respect to water molecules is affected by hydrogen bonding due to a hydrophilic portion typified by a hydroxyl group (OH group) of the material or polarization of the material due to a dipole of the water molecule. As an index indicating the ease of polarization of a material, there is a relative dielectric constant.

  Here, generally, when the proportion of polar groups is high, the dielectric constant increases. Moreover, in order to maintain adhesiveness, wettability is required, and for that purpose, a polar group is required. In general, there is a correlation between dielectric constant and wettability, and a material with a high relative dielectric constant tends to have good wettability, and a material with a low relative dielectric constant tends to be poor.

  This reason is explained by the interaction between dipole moments. The dipole moment of the water molecule is as large as 1.85D (D is Debye) (see, for example, Physics and Chemistry Theory (4th edition, Tokyo Kagaku Dojin) by Atkins p388). In addition, the relationship between the target material dipole moment and relative permittivity is shown by the Clausius-Mosotti relation (relation between polarizability and permittivity) and the fact that the polarizability is proportional to the dipole moment. It can be said that the larger the material, the greater the dipole moment. That is, an attractive force due to the interaction between dipoles acts between a water molecule having a large dipole moment and a material having a high relative dielectric constant (a large dipole moment). For these reasons, the higher the relative dielectric constant, the better the wettability with water. In addition, a material having a low relative dielectric constant (for example, Teflon (registered trademark) or polyethylene) has poor wettability.

  Therefore, it is possible to improve the heat dissipation by improving the volume fraction of the filler in the high thermal conductive filler layer, but if the relative dielectric constant of the filler is high, the electrical insulation characteristics are reduced in a high humidity environment. Cause problems. As described above, it has been difficult for an electrical insulating layer in a conventional rotating electrical machine to have excellent electrical insulation characteristics and high thermal conductivity in a high humidity environment.

  Accordingly, the present invention has been made to solve the above problems, and is an electrical insulating member that can exhibit excellent electrical insulation characteristics and high thermal conductivity even in a high humidity environment. An object is to provide a child coil and a rotating electric machine.

  In order to achieve the above object, according to one aspect of the present invention, there is provided an electrical insulation member that is wound around a conductor bundle of a stator coil of a rotating electrical machine to form an electrical insulation layer, comprising a reinforcing base and the reinforcement A low relative dielectric constant heat conductive layer formed of a thermosetting resin formed on one surface of a base material and containing 40 to 70% by volume of an inorganic filler having a relative dielectric constant of 4 to 10 at a measurement frequency of 50 to 60 Hz; And a mica layer formed on the other surface of the reinforcing substrate and impregnating mica with a thermosetting resin, and the relative dielectric constant of the low relative dielectric constant heat conductive layer at a measurement frequency of 50 to 60 Hz. 4 or less, the thermal conductivity in the thickness direction is 2 W / m · K or more, and the thermal conductivity in the thickness direction of the entire electrical insulating member is 0.35 W / m · K or more. An electrically insulating member is provided.

  According to another aspect of the present invention, there is provided a stator coil for a rotating electrical machine in which an electrical insulation member is wound around a conductor bundle to form an electrical insulation layer, wherein the outermost stator coil constitutes the electrical insulation layer. A stator coil for a rotating electrical machine is provided in which the layer is formed using the above-described electrical insulating member.

  Furthermore, according to one aspect of the present invention, there is provided a stator coil for a rotating electrical machine in which an electrical insulation member is wound around a conductor bundle to form an electrical insulation layer, and a measurement frequency is provided on an outer peripheral surface of the electrical insulation layer. Is made of a thermosetting resin containing 40 to 70% by volume of an inorganic filler having a relative dielectric constant of 4 to 10 at 50 to 60 Hz, and has a relative dielectric constant of 4 or less and a thickness direction of 50 to 60 Hz. There is provided a stator coil for a rotating electric machine comprising an electrically insulating resin layer having a thermal conductivity of 2 W / m · K or more.

  According to another aspect of the present invention, there is provided a rotating electrical machine comprising any one of the above-described stator coils for a rotating electrical machine.

  According to the electrical insulating member, the stator coil for a rotating electrical machine, and the rotating electrical machine of the present invention, excellent electrical insulation characteristics and high thermal conductivity can be exhibited even in a high humidity environment.

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

  FIG. 1 is a diagram schematically showing a cross section of an electrical insulating layer 10 formed around a coil conductor bundle 11 constituting a stator coil 1 for a rotating electrical machine according to an embodiment of the present invention. FIG. 2 is a diagram schematically showing a cross section of an electrical insulating tape 20 that functions as an electrical insulating member according to an embodiment of the present invention.

  As shown in FIG. 1, the electrical insulating layer 10 is formed by winding an electrical insulating tape 20 with a predetermined overlap width and winding it around a coil conductor bundle 11 made of a wire bundle a plurality of times.

  As shown in FIG. 2, the electrical insulating tape 20 has a reinforcing base material 22, a low relative dielectric constant heat conductive layer 23 formed on one surface of the reinforcing base material, and the other surface of the reinforcing base material 22. The formed mica layer 21 is provided.

  The mica layer 21 is made of mica and a thermosetting resin in a semi-cured state, that is, an initial state of the B stage. Any kind of mica can be used as long as it can be formed into a sheet. Mica is roughly classified into hard mica and soft mica, and it is preferable to use hard mica from the viewpoint of improving electrical insulation.

  Moreover, it is preferable that the content rate of the mica in the mica layer 21 is 50-60 volume%. The range of this content rate is preferable because the electrical insulation of the mica layer 21 decreases when the mica content is less than 50% by volume and when it exceeds 60% by volume. Further, the thickness of the mica layer 21 is suitably 50 μm to 250 μm because the mica layer 21 is not broken during the formation of the electrical insulating layer 10 and is suppressed to a thickness that does not impair workability. is there.

  Examples of the thermosetting resin constituting the mica layer 21 include epoxy resins such as bisphenol A type epoxy resin and novolac type epoxy resin, silicone type resins, imide type resins, and the like. Of these resins, it is preferable to use an epoxy resin from the viewpoint of workability and heat resistance.

  Moreover, as a hardening | curing agent contained in a thermosetting resin, an acid anhydride type hardening | curing agent, an amine type hardening | curing agent, imidazoles, Lewis acid salt, Bronsted acid salt etc. are used, for example. Examples of the acid anhydride curing agent include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride. Among these, a metal chelate compound such as aluminum trisethyl acetoacetate can be cited as a curing agent that accelerates the reaction rate of the curing reaction of the thermosetting resin. Examples of amine curing agents include aliphatic polyamines, aliphatic diamines, aromatic polyamines, and cyclic amines. The amount of the curing agent added to the thermosetting resin can be appropriately set as necessary.

  The reinforcement base material 22 is comprised with fiber base materials, such as a glass cloth and a nonwoven fabric, a film, etc., for example. The glass cloth can adjust the thickness of the glass cloth and the number of warps according to the purpose. Moreover, as a nonwoven fabric, a glass fiber nonwoven fabric, a polyester fiber nonwoven fabric, etc. are mentioned, for example. In addition, the thickness of the reinforcing base material 22 is suitably 0.01 mm to 0.1 mm from the reason of workability of winding around the coil conductor bundle 11.

  The low relative dielectric constant heat conductive layer 23 preferably has high heat conductivity and is excellent in electrical insulation. The low relative dielectric constant heat conductive layer 23 is configured so that the relative dielectric constant is 4 or less and the thermal conductivity in the thickness direction is 2 W / m · K or more at a measurement frequency of 50 to 60 Hz. Is preferred. The low relative dielectric constant heat conductive layer 23 is preferably in a semi-cured state, that is, in an initial state of the B stage.

  Here, the low relative dielectric constant heat conductive layer 23 is configured so that the relative dielectric constant is 4 or less and the thermal conductivity in the thickness direction is 2 W / m · K or more at a measurement frequency of 50 to 60 Hz. The reason why this is preferable will be described.

  In a conventional electrical insulating tape composed of a high thermal conductive layer, a mica layer, and a reinforcing substrate, the thermal conductivity in the thickness direction of the entire electrical insulating tape was 0.2 to 0.3 W / m · K. When applied as an electrical insulating layer of a generator, the thermal conductivity in the thickness direction of the entire electrical insulating tape is at least 0.35 W / m · K or more, preferably 0.4 W / m · K or more. Compared to electrical insulation tape, it is hard to say that electrical insulation tape has excellent thermal conductivity. Therefore, the electrical insulating tape 20 is configured such that the thermal conductivity in the thickness direction of the entire electrical insulating tape 20 is 0.35 W / m · K or more. In order to set the thermal conductivity in the thickness direction of the entire electrical insulating tape to 0.35 W / m · K or more, the inventors have studied, and as a result, the thermal conductivity in the thickness direction of the low relative dielectric constant thermal conductive layer 23 It was found necessary to be 2 W / m · K or more. In addition, when the low relative dielectric constant thermal conductive layer 23 is configured so that the thermal conductivity in the thickness direction is 2 W / m · K or more, it maintains electrical insulation, particularly electrical insulation characteristics in a high humidity environment. In order to achieve this, it has been found that it is preferable to reduce the wettability by setting the relative dielectric constant to 4 or less.

  The thermal conductivity in the thickness direction is measured according to JIS A 1412, for example. The relative dielectric constant is measured according to JIS K 6911.

  Therefore, in order to obtain the above-described relative dielectric constant and thermal conductivity in the low relative dielectric constant thermal conductive layer 23, the thermosetting resin constituting the low relative dielectric constant thermal conductive layer 23 has a relative dielectric constant of 4 to 4. It is preferable to contain 10 to 70 volume% of 10 inorganic fillers. In addition, when the content rate of an inorganic filler is smaller than 40 volume%, it becomes difficult to make the heat conductivity of the thickness direction in the low dielectric constant heat conductive layer 23 into 2 W / m * K or more. On the other hand, when the content of the inorganic filler is larger than 70% by volume, the viscosity of the paste obtained by mixing the thermosetting resin and the inorganic filler produced when forming the low dielectric constant heat conductive layer 23 is high. Therefore, it becomes difficult to form the low relative dielectric constant heat conductive layer 23 having a uniform thickness on the surface of the reinforcing base material 22 by coating or the like.

  As the thermosetting resin constituting the low relative dielectric constant heat conductive layer 23, for example, epoxy resin such as bisphenol A type epoxy resin and novolac type epoxy resin, silicone type resin, imide type resin and the like are used. Of these resins, it is preferable to use an epoxy resin from the viewpoint of workability and heat resistance.

  Moreover, as a hardening | curing agent contained in a thermosetting resin, an acid anhydride type hardening | curing agent, an amine type hardening | curing agent, imidazoles, Lewis acid salt, Bronsted acid salt etc. are used, for example. Examples of the acid anhydride curing agent include methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, and methylnadic anhydride. Among these, a metal chelate compound such as aluminum trisethyl acetoacetate can be cited as a curing agent that accelerates the reaction rate of the curing reaction of the thermosetting resin. Examples of amine curing agents include aliphatic polyamines, aliphatic diamines, aromatic polyamines, and cyclic amines. The amount of the curing agent added to the thermosetting resin can be appropriately set as necessary.

  In order to improve the thermal conductivity in the low relative dielectric constant thermal conductive layer 23, the inorganic filler is preferably formed of a material having excellent thermal conductivity. On the other hand, as described above, the relative dielectric constant in the low relative dielectric constant heat conductive layer 23 is preferably suppressed to 4 or less. Therefore, it is preferable to use hexagonal boron nitride, magnesium hydroxide, aluminum hydroxide, or the like, which is an inorganic filler having a relative dielectric constant of 4 to 10 at a measurement frequency of 50 to 60 Hz, as the inorganic filler. In addition, it is preferable to use hexagonal boron nitride, aluminum hydroxide or the like having a low Mohs code from the viewpoint of not damaging the reinforcing substrate 22.

In addition, the shape of the inorganic filler is not particularly limited, and examples thereof include particles and fibers. For example, in the case of particles, the larger the particle diameter (hereinafter referred to as the particle size), the higher the packing can be made. Problems arise. Therefore, the average particle diameter of the particulate inorganic filler is preferably set to 2 to 20 μm in terms of median diameter (d ₅₀ ). Here, the median diameter is a particle diameter (50% cumulative frequency particle diameter) of particles that have reached 50% by integrating their volumes from particles having a small particle diameter. The particle size distribution is measured by a method such as a laser diffraction method. Moreover, in the case of a fibrous form, it is preferable that the aspect ratio which shows the aspect ratio of a filler is 1-4 from the reason for suppressing the viscosity raise at the time of shaping | molding.

  Next, a method for producing the electrical insulating tape 20 will be described.

  First, a predetermined amount of the above-mentioned mica is dispersed in a dispersion medium such as water, mixed, and filtered to form deposited sheet-like mica. Here, when the sheet-like mica is formed, pressure may be applied to the accumulated sheet-like mica.

  Subsequently, the accumulated sheet-like mica is impregnated with a thermosetting resin. The sheet-like mica impregnated with the thermosetting resin is heat-cured to make the thermosetting resin semi-cured, and the mica layer 21 is produced.

  Subsequently, the reinforcing base material 22 is laminated and disposed on the mica layer 21. The mica layer 21 may be formed on the reinforcing base material 22.

  Subsequently, a predetermined amount of the above-described thermosetting resin containing a curing agent is mixed with a predetermined amount of the above-described inorganic filler to form a paste-like mixture. Subsequently, the paste-like mixture is applied or impregnated on the surface of the reinforcing substrate 22, and then heat-cured to make the thermosetting resin in a semi-cured state, whereby the low relative dielectric constant heat conductive layer 23 is formed. An insulating tape 20 is obtained.

  Here, a paste-like mixture is applied or impregnated on one surface of the reinforcing base material 22, laminated so that the other surface of the reinforcing base material 22 faces the mica layer 21, and then heat-cured, and then the mica layer 21. Alternatively, the thermosetting resin of the low dielectric constant heat conductive layer 23 may be simultaneously semi-cured to obtain the electrical insulating tape 20. In addition, conditions, such as heating temperature and heating time which make a thermosetting resin a semi-hardened state, are suitably set according to the kind etc. of thermosetting resin to be used. The thickness of the electrical insulating tape 20 thus manufactured is about 100 μm to 300 μm.

  As shown in FIG. 1, the electrical insulating layer 10 is formed by overlapping the above-described electrical insulating tape 20 with an overlap width of, for example, about 1/2 to 2/3 of the width of the electrical insulating tape 20. It is formed by winding a coil conductor bundle 11 made of a wire bundle a plurality of times. Note that the overlap width is not limited to the above-described range, and is appropriately set according to the intended use.

  In addition, in order to maintain the excellent electric insulation characteristic in the stator coil 1 in which the electric insulation layer 10 is formed as described above, the thickness of the electric insulation layer 10 is the material used or the stator coil 1 is used. It is set as appropriate depending on the conditions and application, etc., for example, about 1 mm to 5 mm.

  Next, the stator slot 101 of the rotating electrical machine that accommodates the stator coil 1 manufactured as described above will be described.

  FIG. 3 is a diagram schematically showing a cross section of the stator core 100 in which the stator coil 1 according to the embodiment of the present invention is accommodated.

  As shown in FIG. 3, the stator coil 1 is accommodated in the stator slot 101 with spacers 110 disposed at the bottom, between the stator coils, and at the top of the stator coil 1. Subsequently, after the wedge 102 is driven, the stator coil 1 is heated, and the thermosetting resin of the electrical insulating tape 20 forming the electrical insulating layer 10 is cured. As a result, the stator coil 1 is fixed in the stator slot 101.

  Here, examples of the rotating electrical machine include a water turbine generator, a wind turbine generator, a steam turbine generator, and the like, and the electrical insulating tape 20 and the stator coil 1 according to the embodiment of the present invention can be applied to these. it can. The electrical insulating tape 20 and the stator coil 1 according to an embodiment of the present invention are particularly suitable for a water turbine generator, a wind turbine generator, a steam turbine generator of a geothermal power plant, etc. that are exposed to a high humidity environment. It is.

  As described above, according to the electrical insulating tape 20 of one embodiment of the present invention, the thermal conductivity can be improved and the relative dielectric constant of the low relative dielectric constant thermal conductive layer 23 on the surface side can be increased. The wettability can be reduced by setting it to 4 or less. Thus, for example, water molecules can be prevented from adhering to the surface of the electrical insulating tape 20 even in a high humidity environment, and a decrease in electrical insulation characteristics can be prevented. Moreover, according to the stator coil 1 provided with the electrical insulating tape 20 and the rotating electrical machine provided with the stator coil 1, the thermal conductivity can be improved in the electrical insulating layer even in a high humidity environment. It is possible to prevent a decrease in electrical insulation characteristics. Therefore, a highly reliable stator coil and rotating device can be provided.

  The embodiments of the present invention can be expanded or modified within the scope of the technical idea of the present invention, and the expanded and modified embodiments are also included in the technical scope of the present invention.

  FIG. 4 is a diagram schematically showing a cross section of an electrical insulating tape 20a having another configuration according to an embodiment of the present invention.

  As shown in FIG. 4, the electrical insulating tape 20 a includes a high thermal conductive layer 30 that is further laminated between the reinforcing base 22 and the low relative dielectric constant thermal conductive layer 23 in the electrical insulating tape 20. . That is, the electrical insulating tape 20a includes a reinforcing base 22, a high heat conductive layer 30 formed on one surface of the reinforcing base, and a low relative dielectric constant heat conductive layer 23 laminated on the high heat conductive layer 30. And a mica layer 21 formed on the other surface of the reinforcing substrate 22.

  Here, the high thermal conductive layer 30 is a layer arranged mainly for the purpose of promoting thermal conduction. The high thermal conductive layer 30 is composed of a thermosetting resin containing 40 to 70% by volume of a filler having a thermal conductivity of 1 W / m · K or more.

Here, as the filler having a thermal conductivity of 1 W / m · K or more, for example, aluminum oxide, aluminum hydroxide, magnesium oxide, magnesium hydroxide, hexagonal boron nitride, or the like is used. Moreover, the shape of a filler is not specifically limited, For example, shapes, such as a particle form and a fiber form, are mentioned. For example, in the case of particles, the larger the particle diameter (hereinafter referred to as the particle size), the higher the packing can be made. Problems arise. Therefore, the average particle diameter of the particulate filler is preferably set to 2 μm to 20 μm in terms of median diameter (d ₅₀ ). Moreover, in the case of a fibrous form, it is preferable that the aspect ratio which shows the aspect ratio of a filler is 1-4 from the reason which suppresses the viscosity raise at the time of shaping | molding.

  Moreover, it is preferable to contain 40-70 volume% of these fillers in a thermosetting resin, when the content rate of a filler is less than 40 volume%, the improvement of the heat conductivity in the high heat conductive layer 30 is aimed at. This is because if the amount exceeds 70% by volume, the high thermal conductive layer 30 cannot be properly formed on the surface of the reinforcing base 22. Further, the thermal conductivity in the thickness direction of the high thermal conductive layer 30 containing the filler in the above range is approximately 2 W / m · K or more, although it varies depending on the type of filler used and the filling rate.

  The reinforcing base material 22, the low relative dielectric constant heat conductive layer 23, and the mica layer 21 that constitute the electrical insulating tape 20a are the same as the respective configurations that constitute the electrical insulating tape 20 described above. Further, the thermosetting resin and the curing agent constituting the high thermal conductive layer 30 are the same as the thermosetting resin and the curing agent constituting the electrical insulating tape 20 described above. Further, at least the mica layer 21 and the low relative dielectric constant heat conductive layer 23 are preferably in a semi-cured state, that is, an initial state of the B stage, and the high heat conductive layer 30 is also semi-cured, that is, in the B stage. More preferably, it is in the initial state.

  Next, a method for producing the electrical insulating tape 20a will be described.

  First, a predetermined amount of the above-mentioned mica is dispersed in a dispersion medium such as water, mixed, and filtered to form deposited sheet-like mica. Here, when the sheet-like mica is formed, pressure may be applied to the accumulated sheet-like mica.

  Subsequently, the accumulated sheet-like mica is impregnated with a thermosetting resin. The sheet-like mica impregnated with the thermosetting resin is heat-cured to make the thermosetting resin semi-cured, and the mica layer 21 is produced.

  Subsequently, the reinforcing base material 22 is laminated and disposed on the mica layer 21. The mica layer 21 may be formed on the reinforcing base material 22.

  A predetermined amount of the above-mentioned thermosetting resin containing a curing agent is mixed with a predetermined amount of the above-described filler contained in the high thermal conductive layer 30 to form a paste-like mixture. Subsequently, this paste-like mixture is applied or impregnated on the surface of the reinforcing substrate 22, and then heat-cured to make the thermosetting resin semi-cured to form the high thermal conductive layer 30.

  Subsequently, a predetermined amount of the above-described thermosetting resin containing a curing agent is mixed with a predetermined amount of the above-described inorganic filler to form a paste-like mixture. Subsequently, this paste-like mixture is applied to the surface of the high thermal conductive layer 30, and then heat-cured to make the thermosetting resin semi-cured to form the low dielectric constant thermal conductive layer 23, and the electric insulating tape. 20a is obtained.

  According to this electrical insulating tape 20a, the thermal conductivity can be further improved, and the relative dielectric constant of the low relative dielectric constant thermal conductive layer 23 on the surface side can be reduced to 4 or less to reduce the wettability. it can. Thus, for example, water molecules can be prevented from adhering to the surface of the electrical insulating tape 20 even in a high humidity environment, and a decrease in electrical insulation characteristics can be prevented. Moreover, according to the stator coil 1 provided with the electrical insulating tape 20a and the rotating electrical machine provided with the stator coil 1, the thermal conductivity can be improved in the electrical insulating layer even in a high humidity environment. It is possible to prevent a decrease in electrical insulation characteristics. Therefore, a highly reliable stator coil and rotating device can be provided.

  In addition, the above-described electrical insulating tape 20 and electrical insulating tape 20a are not limited to being wound directly around the coil conductor bundle 11 made of a wire bundle, but, for example, the conventional electrical tape wound around the coil conductor bundle 11 is used. You may wind around the outer periphery of an insulating layer. That is, the outermost layer of the electrical insulating layers of the stator coil 1 may be configured by the electrical insulating tape 20 or the electrical insulating tape 20a described above.

  Further, a paste-like mixture prepared by forming the above-described low relative dielectric constant heat conductive layer 23 in which a thermosetting resin containing a curing agent is mixed with an inorganic filler is placed around the coil conductor bundle 11. You may apply | coat to the outer periphery of the conventional electrical insulation layer wound, and may form an electrical insulation resin layer.

  Also in the stator coil of these structures, the same effect as the effect in the stator coil 1 mentioned above can be obtained.

  Next, it is based on an Example and a comparative example that the stator coil 1 provided with the electrical insulation tape 20 of one embodiment which concerns on this invention is excellent in thermal conductivity and the electrical insulation characteristic in a high humidity environment. I will explain.

(Evaluation of thermal conductivity and electrical insulation properties)
Since the stator coil used here has the same configuration as the stator coil 1 shown in FIG. 1, it will be described with reference to FIG.

  First, the electrical insulating tape 20 was produced as follows.

  Bisphenol A epoxy resin (AER331 manufactured by Asahi Kasei Co., Ltd. and AER661 manufactured by Asahi Kasei Co., Ltd. at 25:35), novolak epoxy resin (DEN438 manufactured by Asahi Kasei Co., Ltd.), and acid anhydride curing agent (methylhexahydrophthalic anhydride) Were mixed in a weight ratio of 70:30:80 to obtain an adhesive resin. A mica paper made of hard baked mica was impregnated with this adhesive resin to form a prepreg, which was then heat-treated in a heating and drying furnace to obtain a semi-cured state, whereby a mica layer 21 was obtained.

  Moreover, the above-mentioned adhesive resin is a hexagonal boron nitride having a relative dielectric constant of 4 at a measurement frequency of 50 to 60 Hz as an inorganic filler, and the content is 35% by volume, 40% by volume, 45% by volume, and 50% by volume. %, 55% by volume, 60% by volume, and 65% by volume were mixed to prepare 7 types of inorganic filler mixed materials.

  Subsequently, a woven fabric made of glass fibers serving as the reinforcing base material 22 is laminated on the mica layer 21, and further, each inorganic filler mixed material described above is applied to the surface of the woven fabric and heated in a heating and drying furnace. A semi-cured state was obtained by treatment, and a low relative dielectric constant heat conductive layer 23 was formed to obtain an electrical insulating tape 20 having a thickness of 0.2 mm and a width of 25 mm. Here, since the electrical insulating tape 20 having the low relative dielectric constant heat conductive layer 23 formed by each of the above-mentioned seven types of inorganic filler mixed materials was obtained, the seven types of electrical insulating tape 20 were obtained. .

  Here, the low dielectric constant heat conductive layer 23 having a hexagonal boron nitride content of 35% by volume, 40% by volume, 45% by volume, 50% by volume, 55% by volume, 60% by volume, and 65% by volume is provided. The electrical insulating tape 20 is shown as Sample 1, Sample 2, Sample 3, Sample 4, Sample 5, Sample 6, and Sample 7, respectively. Sample 2 to Sample 7 are examples in which the content of the inorganic filler falls within the scope of the present invention, while Sample 1 is a comparative example in which the content of the inorganic filler falls outside the scope of the present invention. is there.

  Further, in order to investigate the influence of the type of filler of the low relative dielectric constant thermal conductive layer 23 on the thermal conductivity and electrical insulation characteristics, the above-mentioned adhesive resin is used as the filler, and the relative dielectric constant at a measurement frequency of 50 to 60 Hz is used. Aluminum oxide having a rate of 9 is mixed so that the content is 35% by volume, 40% by volume, 45% by volume, 50% by volume, 55% by volume, 60% by volume, 65% by volume, A filler mixed material was prepared. And the woven fabric which consists of the glass fiber used as the reinforcement base material 22 is laminated | stacked on the mica layer 21 produced similarly to the case of producing the samples 1-7, Furthermore, these fillers are further provided on the surface of the woven fabric. The mixed material was applied and heat-treated in a heating / drying furnace to be in a semi-cured state to form a filler-containing layer, thereby obtaining an electrical insulating tape 20 having a thickness of 0.2 mm and a width of 25 mm.

  Here, the electrical insulating tape 20 having a filler-containing layer with an aluminum oxide content of 35% by volume, 40% by volume, 45% by volume, 50% by volume, 55% by volume, 60% by volume, and 65% by volume, respectively. Sample 8, sample 9, sample 10, sample 11, sample 12, sample 13, and sample 14 are shown. Samples 8 to 14 are comparative examples in which the relative dielectric constant of the filler is outside the scope of the present invention.

  Further, the thermal conductivity and electrical insulation characteristics of the electrical insulating tape 20a having the low relative dielectric constant thermal conductive layer 23 and the high thermal conductive layer 30 according to the present invention shown in FIG. 4 were examined. Therefore, a woven fabric made of glass fibers to be the reinforcing base material 22 is laminated on the mica layer 21 produced in the same manner as in the case of producing the samples 1 to 7, and the above-described oxidation is performed on the surface of the woven fabric. A filler mixed material in which aluminum was mixed so as to have a content rate of 45% by volume was applied and heat-treated in a heating and drying furnace to be in a semi-cured state, whereby the high thermal conductive layer 30 was formed.

  Subsequently, an inorganic filler mixed material in which the above-described hexagonal boron nitride is mixed so as to have a content of 45% by volume is applied to the surface of the high thermal conductive layer 30, and heat-treated in a heating and drying furnace. A semi-cured state was formed, a low relative dielectric constant heat conductive layer 23 was formed, and an electrical insulating tape 20a having a thickness of 0.24 mm and a width of 25 mm was obtained. The low relative dielectric constant heat conductive layer 23 and the high heat conductive layer 30 were configured to have the same thickness. Moreover, since this electrical insulating tape 20a is an electrical insulating tape having the configuration according to the present invention, it is an example, and the electrical insulating tape 20a is shown as a sample 15.

  The measurement of thermal conductivity and relative dielectric constant is a process of preparing a test piece having a diameter of 60 mm from each of the above-described samples, and heating them for 20 hours at a temperature of 150 ° C. to cure the thermosetting resin. Went. And the heat conductivity of the thickness direction of the sample was measured according to JIS A1412. Further, in order to measure the thermal conductivity in the thickness direction of only the low relative dielectric constant thermal conductive layer 23 or the filler-containing layer, the filler mixed material for constituting each is poured into a mold having a predetermined shape and heated. A test piece having a diameter of 60 mm and a thickness of 2 mm was produced by heat treatment in a drying furnace. The thermal conductivity in the thickness direction of each test piece was measured by the same method as the above-described thermal conductivity measurement method. Moreover, the measurement of the dielectric constant in the measurement frequency 50-60Hz in the low dielectric constant heat conductive layer 23 or the filler containing layer was performed according to JISK6911.

  In addition, in order to evaluate the electrical insulation characteristics in a high humidity environment, a test simulating corona degradation was performed by the following method. FIG. 5 is a diagram schematically showing an apparatus for performing a test simulating corona degradation.

  First, each sample produced as described above was wound around the coil conductor bundle 11 six times so that the overlap width was ½, and the electric insulation layer 10 was formed, whereby the stator coil 1 was obtained. Subsequently, the stator coil 1 was subjected to a heat treatment at a temperature of 150 ° C. for 20 hours to cure the thermosetting resin.

  Subsequently, as shown in FIG. 5, a semiconductive paint 151 having a surface resistance of 5000Ω was applied in the circumferential direction of the surface of the manufactured stator coil 1 so as to have a width of 100 mm. Further, from the applied position, a gap of 100 mm is provided in the axial direction (longitudinal direction) of the stator coil 1 so that the width of the semiconductive paint 151 is 100 mm in the circumferential direction of the surface of the stator coil 1. It was applied to. That is, the semiconductive paint 151 was applied to the circumferential direction of the surface of the stator coil 1 at two locations in the axial direction (longitudinal direction) of the stator coil 1 with an interval of 100 mm. Subsequently, the stator coil 1 was heat-treated at 60 ° C. for 20 hours, and the applied semiconductive paint 151 was dried. In addition, the thickness of the stator coil 1 before applying the semiconductive paint 151 and the semiconductive paint 151 after applying and drying the semiconductive paint 151 were applied to the two places where the semiconductive paint 151 was applied. The thickness of the stator coil 1 including the portion was measured with a dial gauge.

  Subsequently, as shown in FIG. 5, the stator coil 1 is put in a constant temperature and humidity chamber 150 made of ESPEC (having an insulator for a high voltage test), and the humidity inside the constant temperature and humidity chamber 150 is 80%. %, The temperature was maintained at a high humidity environment of 23 ° C., and a voltage was applied from the power source 152 to the stator coil 1 for 1000 hours under the condition of 50 Hz-20 kV. In addition, the high voltage test apparatus made from Keinan Electric was used for the voltage application.

  Subsequently, the stator coil 1 to which a voltage is applied for 1000 hours is taken out from the thermo-hygrostat, and the thickness of the stator coil 1 including the portion where the semiconductive paint 151 is applied is applied to two places where the semiconductive paint 151 is applied. Was measured with a dial gauge. Based on this measurement result, the deterioration rate of the electrical insulating layer 10 was obtained. Here, the deterioration rate of the electrical insulating layer 10 is based on the measured value measured with a dial gauge, from the thickness of the electrical insulating layer 10 before the voltage is applied, to the thickness of the electrical insulating layer 10 after the voltage is applied. The percentage is obtained by dividing the value by the thickness of the electrical insulating layer 10 before the voltage is applied. Note that the thickness of the coating layer of the semiconductive paint 151 did not change before and after the voltage was applied. Moreover, it shows that the electrical insulation characteristic in a high humidity environment is so bad that a deterioration rate is high.

  Table 1 shows the measurement results of the thermal conductivity, relative dielectric constant, and deterioration rate of each sample.

  As shown in Table 1, the thermal conductivity in the thickness direction of the entire electrical insulating tape 20 in Samples 2 to 7 and Sample 15 is 0.35 or more. In Samples 2 to 7 and Sample 15, the thermal conductivity in the thickness direction of the low relative dielectric constant heat conductive layer 23 is 2 or more, and the relative dielectric constant of the low relative dielectric constant heat conductive layer 23 is 4 or less. Yes, the deterioration rate was 8% at the highest. On the other hand, in the sample 1 in which the content of hexagonal boron nitride is 35% by volume, the thermal conductivity in the thickness direction of the entire electric insulating tape 20 and the low thermal conductivity are lower than those in the samples 2 to 7 and the sample 15. Both of the thermal conductivities of the relative dielectric constant heat conductive layer 23 were low. In Samples 8 to 14, which contain aluminum oxide as a filler in the low relative dielectric constant heat conductive layer 23, the relative dielectric constant is a high value exceeding 4, and the deterioration rate is also from Sample 2 to Sample. It was higher than 7. From these results, it was found that Sample 2 to Sample 7 and Sample 15 had excellent electrical insulation characteristics while having high thermal conductivity even in a high humidity environment.

  In addition, a stator coil in which the electrical insulating tape 20 of the sample 3 is wound around the stator coil having the sample 11 having the same configuration as that of the conventional electrical insulating layer as the electrical insulating layer, and the sample 6 described above. The stator coil 1 around which the electrical insulating tape 20 was wound was produced, and the stator coil was heat-treated at a temperature of 150 ° C. for 20 hours to cure the thermosetting resin. Although not shown in Table 1, the thermal conductivity and deterioration rate in the thickness direction of the entire electrical insulating layer including the electrical insulating tape 20 constituting the two types of stator coils 1 were measured. As a result, the thermal conductivity in the thickness direction of the entire electrical insulating layer including the electrical insulating tape 20 in Sample 3 was 0.43 W / m · K, and the degradation rate was 4. Moreover, the thermal conductivity in the thickness direction of the entire electrical insulating layer including the electrical insulating tape 20 in Sample 6 was 0.44 W / m · K, and the deterioration rate was 2. Thus, it has been found that by winding the electrical insulating tape 20 according to the present invention around a conventional stator coil, excellent electrical insulation characteristics can be obtained while having high thermal conductivity.

  In addition, an inorganic filler mixed material for forming the above-described low relative dielectric constant heat conductive layer 23 of the sample 3 is provided around the stator coil having the sample 11 having the same configuration as the conventional electric insulating layer as the electric insulating layer. It apply | coated and heat-processed in the heating-drying furnace, it was made to harden | cure, and the electric resin insulating layer was formed. Although not shown in Table 1, the deterioration rate of the entire insulating layer including the electric insulating layer and the electric resin insulating layer in this stator coil was 6%. Further, the thermal conductivity in the thickness direction of the entire insulating layer composed of the electric insulating layer and the electric resin insulating layer was 0.47 W / m · K. In this way, by forming an electric resin insulating layer made of an inorganic filler mixed material that forms the low dielectric constant heat conductive layer 23 of the electric insulating tape 20 according to the present invention around the conventional stator coil, It has been found that excellent electrical insulation characteristics can be obtained while having high thermal conductivity.

The figure which shows typically the cross section of the electrical-insulation layer formed in the circumference | surroundings of the coil conductor bundle which comprises the stator coil for rotary electric machines of one Embodiment which concerns on this invention. The figure which showed typically the cross section of the electrical insulation tape which functions as an electrical insulation member of one embodiment which concerns on this invention. The figure which showed typically the cross section of the stator core in which the stator coil of one Embodiment which concerns on this invention was accommodated. The figure which showed typically the cross section of the electric insulation tape of the other structure of one Embodiment which concerns on this invention. The figure which showed typically the apparatus for performing the test which simulated corona degradation. The figure which showed typically the cross section of the conventional stator iron core in which the stator coil was accommodated in the stator slot.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Stator coil, 10 ... Electrical insulation layer, 11 ... Coil conductor bundle, 20, 20a ... Electrical insulation tape, 21 ... Mica layer, 22 ... Reinforcement base material, 23 ... Low relative dielectric constant heat conduction layer, 30 ... High heat Conductive layer, 100: stator core, 101: stator slot, 102: wedge, 110: spacer.

Claims (6)

An electrical insulation member that is wound around a conductor bundle of a stator coil of a rotating electrical machine to form an electrical insulation layer,
A reinforcing substrate;
Low relative dielectric constant heat conduction formed of a thermosetting resin formed on one surface of the reinforcing base material and containing 40 to 70% by volume of an inorganic filler having a relative dielectric constant of 4 to 10 at a measurement frequency of 50 to 60 Hz. Layers,
A mica layer formed on the other surface of the reinforcing substrate and impregnated with mica in a thermosetting resin,
The low relative dielectric constant heat conductive layer has a relative dielectric constant of 4 or less at a measurement frequency of 50 to 60 Hz and a thermal conductivity of 2 W / m · K or more in the thickness direction, and the thickness direction of the entire electrical insulating member The electrical insulation member characterized by having a thermal conductivity of 0.35 W / m · K or more.   A high thermal conductive layer made of a thermosetting resin containing 40 to 70% by volume of a filler having a thermal conductivity of 1 W / m · K or more is further provided between the reinforcing base and the low relative dielectric constant thermal conductive layer. The electrically insulating member according to claim 1, wherein the electrically insulating member is laminated.   The electrical insulating member according to claim 1 or 2, wherein at least the thermosetting resin constituting the low dielectric constant heat conductive layer and the mica layer is in a semi-cured state. A stator coil for a rotating electrical machine formed by winding an electrical insulation member around a conductor bundle to form an electrical insulation layer,
A stator coil for a rotating electrical machine, wherein at least the outermost layer constituting the electrical insulation layer is formed using the electrical insulation member according to any one of claims 1 to 3. A stator coil for a rotating electrical machine formed by winding an electrical insulation member around a conductor bundle to form an electrical insulation layer,
The outer peripheral surface of the electrical insulating layer is made of a thermosetting resin containing 40 to 70% by volume of an inorganic filler having a relative dielectric constant of 4 to 10 at a measurement frequency of 50 to 60 Hz, and the measurement frequency is 50 to 60 Hz. A stator coil for a rotating electrical machine comprising an electrically insulating resin layer having a dielectric constant of 4 or less and a thermal conductivity in a thickness direction of 2 W / m · K or more.   A rotating electrical machine comprising the stator coil for a rotating electrical machine according to claim 4 or 5.

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