JP4434854B2 - Rotating electric machine - Google Patents

Description

  The present invention relates to a rotating electrical machine having an improved stator insulation structure.

FIG. 11 shows a general insulation structure of a stator of a rotating electrical machine. In the iron core 101 of the stator 100, a plurality of slots 101a are concentrically arranged at equal intervals. A U-shaped slot insulator 102 using calendered aramid paper or the like is mounted in the slot 101a, and a synthetic resin enamel such as polyamide imide enamel copper wire is placed inside the slot insulator 102. A winding 103 using a wire 103a is accommodated and wrapped with a slot insulator 102, and then a wedge material 104 formed of, for example, a calendered aramid paper or the like into a half-U shape is driven into the winding 103. Fixed. In addition, interphase paper is inserted between the phases at the coil end portion (not shown) of the winding 103 to melt the phases. Furthermore, the winding 103 contained in the slot 101a is by varnish treatment, the varnish 105 is impregnated into the slot 101a and the coil end portion, it is heated and cured and is fixed integrally molded (see Patent Document 1) .

  Conventionally, devices that use a rotating electrical machine are often controlled at a variable speed by an inverter in order to increase energy efficiency. The inverter is driven at a frequency of about 2 kHz to several tens of kHz, for example, a PWM pulse. A surge voltage is generated every time. The surge voltage is a phenomenon in which a voltage higher than the output voltage of the inverter is applied under the influence of the surrounding electrical system such as the length of the cable and the presence or absence of a capacitor. Further, since the pulse waveform is steep, partial discharge is likely to occur in the enameled wire 103a used in the winding 103, so that a local temperature rise occurs or occurs in the coating film of the enameled wire 103a. The ozone that has been applied acts in a complex manner, causing the insulation of the enamel film to deteriorate at an accelerated rate, thereby shortening the life of the equipment. Furthermore, in recent years, rotating electrical machines are also becoming smaller, and the winding temperature tends to increase more and more. For this reason, measures are taken to improve the heat resistance deterioration of the insulating material used in each part, or the thermal conductivity of each part is improved.

  In order to increase the durability due to this surge voltage, it is possible to increase the space factor by increasing the enamel coating film or increasing the amount of impregnating resin in the winding 103 of the rotating electrical machine. In addition to problems such as a decrease in efficiency and an increase in expenses, there are many cases where the desired reliability cannot be obtained even if these measures are taken. For this purpose, an enameled wire coating having excellent characteristics with respect to the inverter surge voltage and an insulation structure with high resistance against the surge voltage are required.

  In addition, in order to cope with the temperature rise of the winding 103, it is possible to improve the heat resistance deterioration of the insulating material relatively easily, but the cost of the material itself is large, and the temperature range is limited. There is also. And as a measure to increase the thermal conductivity, there is usually a method to increase the heat dissipation effect by reducing the thickness of organic materials with poor thermal conductivity such as resin, but the reduction in thickness directly leads to a decrease in insulation performance In many cases, it is difficult to achieve both heat conduction performance and insulation performance in an insulating material.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotating electrical machine capable of improving heat dissipation by improving heat conduction performance while maintaining insulation reliability. Objective.

According to the first aspect of the present invention, boron nitride or magnesium oxide as a first filler having a thermal conductivity of at least 1.0 W / mK as a treatment varnish for a winding of a rotating electrical machine, and a grain size of the first A sol-gel using a metal alkoxide as a raw material is a resin that uniformly contains carbon black or alumina as a second filler that is 0.15 times or less that of It is characterized by being precipitated and dispersed by the method .
According to such a configuration, the second filler having a particle size of 0.15 times or less with respect to the first filler is compared with the first filler having a thermal conductivity of 1.0 W / mK or more. By containing uniformly, the processing varnish which improved the heat-dissipating property by improving heat-conducting performance, maintaining insulation reliability, can be used for a rotary electric machine.

The invention according to claim 2 is a first filler having a thermal conductivity of at least 1.0 W / mK as a slot insulator inserted between the winding and the iron core of the rotating electrical machine for ground insulation. A single sheet of resin containing uniformly boron nitride or magnesium oxide as a carbon black or alumina as a second filler having a particle size of 0.15 times or less that of the first filler wood, or used in the bonding material with the other sheet material, the second filler, and wherein the dispersed precipitated by the sol-gel method using metal alkoxide as a raw material.
According to such a structure, the slot insulator which has the same effect as Claim 1 can be used for a rotary electric machine.

The invention according to claim 3 uses an adhesive electric wire formed by applying an adhesive layer of a B stage on the surface of an enameled wire as a magnet wire of a winding of a rotating electrical machine. Boron nitride or magnesium oxide as the first filler having a thermal conductivity of not less than / mK and carbon as the second filler having a particle size of 0.15 times or less compared to the first filler It contains black or alumina uniformly, and the second filler is precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material .
According to such a configuration, the bonded electric wire having the same effect as that of the first aspect can be used for the rotating electrical machine.

According to a fourth aspect of the present invention, boron nitride or magnesium oxide as a first filler having a thermal conductivity of at least 1.0 W / mK as a wedge material of a rotating electric machine, and a first filler having a particle size of using carbon black or alumina and uniformly containing the resin as a second filler is 0.15 times or less compared single sheet material, or in the bonding material with the other sheet material and the The second filler is characterized by being precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material .
According to such a configuration, a wedge material having an effect similar to that of the first aspect can be used for the rotating electrical machine.

  ADVANTAGE OF THE INVENTION According to this invention, the rotary electric machine which can improve the heat dissipation can be provided by improving a heat conductive performance, maintaining insulation reliability.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, FIG. 1 is a partial cross-sectional view of a stator of a rotating electrical machine. As shown in FIG. 1, a plurality of slots 2a are arranged concentrically at equal intervals in the iron core 2 of the stator 1 of the rotating electrical machine. The slot 2a has a substantially trapezoidal shape. A U-shaped slot insulator 3 is inserted into the slot 2a.

  As shown in FIG. 2, the slot insulator 3 is made of, for example, a film of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide or the like, or a sheet material 4 made of synthetic paper such as aramid. Has been configured. In the synthetic resin 5, boron nitride or magnesium oxide as a first filler and a second filler deposited by a sol-gel method using a metal alkoxide as a raw material are uniformly contained.

  FIG. 5 shows a method for producing the synthetic resin 5 by the sol-gel method. In FIG. 5, the synthetic resin 5 is composed of, for example, tetraethoxysilane (30 ml) having high purity as metal alkoxide and polydimethylsiloxane ( 20 ml), isopropyl alcohol (15 ml) and tetrahydrofuran (10 ml) are stirred and mixed with a stirrer at room temperature and normal pressure for 2 hours to obtain liquid A. Then, a solution obtained by stirring and mixing 2N hydrochloric acid (10 ml) and distilled water (30 ml) was added dropwise to the solution A with stirring, and the mixed liquid was kept in a sealed state at 70 ° C. for 48 hours. Warm for hours to obtain solution B.

  Further, 60 vol% of hexagonal boron nitride (or magnesium oxide) as a first filler having a thermal conductivity of 1.0 W / mK or more is filled in this liquid B, and stirred and mixed at 300 ° C. Is dried and cured to form a plate-shaped synthetic resin. Here, since the synthetic resin 5 is laminated as a slot insulator 3 on one side of the sheet material 4 in a prepreg state, the synthetic resin 5 is mixed with stirring and dried and cured at 300 ° C. It is applied as a state, and as a result, it is configured as being attached to the slot insulator 3.

As shown in FIG. 2, the slot insulator 3 is inserted into the slot 2 a so that the side of the synthetic resin 5 bonded in the prepreg state is in contact with the inner wall of the slot 2 a of the iron core 2.
Subsequently, as shown in FIG. 1, a winding 7 is formed by inserting an adhesive wire 6 as a magnet wire inside the slot insulator 3. The winding 7 is, for example, a three-phase winding composed of R, S, and T phases and is star-connected, and each phase winding includes a plurality of windings connected in series corresponding to a plurality of poles. It is connected to an inverter (not shown) via a power supply lead wire.

As shown in FIG. 4 , the bonded electric wire 6 is formed by applying a synthetic resin 10a on the surface of an enamel layer 9 around the conductor 8 (the conductor 8 and the enamel layer 9 constitute an enameled wire that is a normal magnet wire). The formed adhesive layer 10 is formed. When the adhesive wire 6 is heated at a predetermined temperature, the adhesive layer 10 is fused, the adhesive wires 6 are bonded to each other, and the winding 7 constituted by the adhesive wire 6 is integrated. The synthetic resin 10a (adhesive layer 10) is the same material as the synthetic resin 5 in the case of the slot insulator 3, and is formed as the adhesive layer 10 when it is stirred and mixed and dried and cured at 300 ° C.

  Then, as shown in FIG. 1, a wedge material 11 in which a sheet material is formed in a semi-U shape is driven into the opening of the slot 2 a of the iron core 2, and the winding 7 is fixed. The sheet material used as the wedge material 11 is constituted by, for example, a synthetic resin laminated on one side of a synthetic paper such as a film such as polyethylene terephthalate, polyethylene naphthalate or polyphenylene sulfide, or an aramid, and the synthetic resin is composed of the slot insulator 3. The same material as that of the synthetic resin 5 is formed.

Subsequently, the winding 7 housed in the slot 2a is subjected to a process of impregnating with a varnish 12 for integrally molding. This treatment is, for example, a dripping impregnation varnish treatment. While rotating the stator 1, the varnish 12 is dropped from both sides of the coil end portions 7R to 7T (see FIG. 3 ) of the winding 7 by the nozzles, and between the bonded electric wires 6 A process in which the winding 7 in the slot 2a is filled with the varnish 12 by capillary action, and the varnish 12 is impregnated in the slot 2a and the coil end portions 7R to 7T, and then heat-cured (corresponding to the B stage). It is. The impregnated varnish 12 is made of a synthetic resin, and this synthetic resin is the same material as that of the slot insulator 3, and is stirred and mixed, filled in the slot 2a, and dried and cured.

Then, a rotor (not shown) is arranged in the stator 1 having an insulating structure to constitute a rotating electric machine.
Thus, the rotation speed of the rotor is changed by PWM control of the winding 7 of the stator 1 by the inverter.

The operation of the present invention will be described below with reference to FIGS.
First, experimental results regarding the correlation between the particle size and the heat transfer coefficient will be described with reference to FIGS.
FIG. 6 shows the change in thermal conductivity when a mixture of boron nitride and isopropylene elastomer having the same shape as mica is filled with carbon black having an average particle size of 90 nm. The vertical axis indicates the thermal conductivity ( W / mK) represents the horizontal axis represents the volume ratio between the complex and the carbon black of boron and isopropylene-based elastography M a nitride (vol%).
The thermal conductivity was measured by a laser flash method. Here, the filling amount of boron nitride was constant at a volume amount 0.6 times (60 vol%) with respect to the volume sum of boron nitride and isopropylene elastomer.

  From FIG. 6, the thermal conductivity is increased by filling with carbon black. Compared with the case where carbon black is not filled and the case where carbon black is filled with 10 vol%, the thermal conductivity is about 3.7 W / mK, which is nearly four times higher. I was able to get it. This is because the elastic modulus of the resin between the boron nitrides is increased due to the uniform presence of the carbon black particles between the boron nitride particles, and as a result, the heat flow between the boron nitride particles is improved. It is thought that it improved.

  FIG. 7 shows changes in thermal conductivity when a mixture of boron nitride and isopropylene elastomer is filled with alumina having an average particle size of 70 nm instead of carbon black. According to this, a further increase in thermal conductivity was observed as compared with carbon black, and a thermal conductivity of about 4.7 W / mK could be obtained when alumina was filled at about 12.5 vol%.

FIG. 8 shows the change in thermal conductivity when a mixture of boron nitride and isopropylene elastomer is filled with alumina having different particle sizes, the vertical axis shows the thermal conductivity (W / mK), and the horizontal axis Indicates the particle size ratio of boron nitride as the first filler and alumina as the second filler.
It can be seen from FIG. 8 that the thermal conductivity increases in the range where the particle size ratio is smaller than about 0.1 times. Thus, a material having high thermal conductivity can be obtained by setting the particle size of the second filler to 0.15 times or less of the particle size of the first filler.

  As described above, the point of increasing the thermal conductivity is that the second filler is dispersed in the first filler. In order to further improve the thermal conductivity, the filler is chemically separated. It can be seen that it is important that they are connected by bonding or evenly dispersed. Therefore, if a method of precipitating the second filler by applying the sol-gel method as a method for uniformly dispersing the second filler in the first filler is applied between the first fillers. Uniform dispersion of the two fillers is possible.

According to such a configuration, the resin used as the adhesive layer 10 of the bonded electric wire 6 includes boron nitride (or magnesium oxide) as the first filler having a thermal conductivity of 1.0 W / mK or more, and metal alkoxide. since a second filler which is deposited by a sol-gel method as a raw material tetraethoxysilane is uniformly dispersed, even while maintaining the insulation reliability to the inverter surge voltage during inverter drive, improving the thermal conductivity By making it, heat dissipation can be improved. Furthermore, hexagonal boron nitride and magnesium oxide, which are the first fillers, have a low Mohs hardness and are soft, and thus can prevent damage to the base material and enamel wire.

Then, the varnish 12, a boron nitride (or magnesium oxide) as a first filler, the second filler is deposited by a sol-gel method as a raw material tetraethoxysilane are uniformly dispersed , while maintaining the insulation reliability of the varnish 12, it is possible to improve the heat transfer, yet, since it is integrated with the adhesive layer 10 and the varnish 12 in the process is heated and cured, generated from the adhesive lines 6 By efficiently transmitting Joule heat to the iron core 2 side, heat dissipation can be enhanced. Furthermore, damage to the substrate and enameled wire can be prevented by the hexagonal boron nitride and magnesium oxide as the first filler.

Further, the synthetic resin 5 constituting a slot insulator 3 includes a boron nitride (or magnesium oxide) as a first filler, and a second filler which is deposited by a sol-gel method as a raw material tetraethoxysilane Since it is uniformly distributed, the heat transfer rate can be improved while maintaining the insulation reliability of the slot insulator 3 at the bonded portion between the slot insulator 3 and the iron core 2, and the slot insulator 3 is further improved. Since the core 2 and the iron core 2 are in close contact with each other, the heat dissipating property can be enhanced by efficiently transmitting the Joule heat generated in the bonded electric wire 6 to the iron core 2 side. Furthermore, damage to the substrate and enameled wire can be prevented by the hexagonal boron nitride and magnesium oxide as the first filler.

Further, the synthetic resin of the wedge member 11, and boron nitride (or magnesium oxide) as a first filler, tetraethoxysilane and uniformly second filler which is deposited by a sol-gel method as a raw material Since it is dispersed, it is possible to improve the heat dissipating property by improving the heat transfer performance of the wedge material portion, which has been a large heat resistance in the past, while maintaining the insulation reliability of the wedge material 11. Furthermore, damage to the substrate and enameled wire can be prevented by the hexagonal boron nitride and magnesium oxide as the first filler.

  Therefore, while maintaining the insulation reliability against the inverter surge voltage generated by the inverter drive, the heat dissipation performance can be improved by improving the heat conduction performance of the entire rotating electric machine, and thus the entire rotating electric machine. The temperature can be reduced.

(Second embodiment)
FIG. 9 and FIG. 10 show a second embodiment of the present invention, and different points from the first embodiment will be described. In the first embodiment, a configuration for forming the synthetic resin 5 using the sol-gel method including isopropyl alcohol (isopropyl-based elastography M a), the synthetic resin by using a sol-gel method using an epoxy-based resin The case where it forms is demonstrated. In this case, the sol-gel method involves stirring tetraethoxysilane (30 ml), silane coupling agent A187 (10 ml), distilled water (5 ml), and ethanol (10 ml) with a 200 ml beaker for 10 minutes, while stirring. A liquid in which diethyleneamine (0.6 ml) was dropped was used as a B liquid, and 60 vol% boron nitride (or magnesium oxide) was filled in the B liquid. The resin filled with these is dried and cured at 350 ° C. to obtain a synthetic resin. Other configurations are the same as those in the above embodiment.

Next, experimental results regarding the correlation between the particle size and the heat transfer coefficient will be described with reference to FIGS.
FIG. 9 shows changes in thermal conductivity when a composite of boron nitride and epoxy resin is filled with carbon black having an average particle size of 90 nm, and the vertical axis shows thermal conductivity (W / mK). The horizontal axis represents the volume ratio (vol%) between the composite of boron nitride and epoxy resin and carbon black. The thermal conductivity was measured by a laser flash method. Here, the filling amount of boron nitride was constant at a volume amount 0.6 times (60 vol%) with respect to the volume sum of boron nitride and epoxy resin.

  From FIG. 9, the thermal conductivity is increased by filling with carbon black, and the thermal conductivity of about 6.5 W / mK, which is more than twice that of the case of not filling carbon black and the case of filling 1 vol% of carbon black. Could get. This is because, as in the first embodiment, the carbon black particles are uniformly present between the boron nitride particles, whereby the elastic modulus of the resin between the boron nitrides is increased. As a result, the heat between the boron nitride particles is increased. It is thought that the heat conduction performance was improved because the flow was improved.

FIG. 10 shows a change in thermal conductivity when a composite of boron nitride and an epoxy resin is filled with alumina having an average particle size of 70 nm instead of carbon black. A further increase in thermal conductivity was observed compared to carbon black, and a thermal conductivity of about 7.4 W / mK could be obtained when 4 vol% alumina was filled.
According to the rotating electrical machine having the above-described insulating configuration, the same effect as in the first embodiment can be obtained.

(Modification)
The present invention is not limited to the above embodiment, but can be modified or expanded as follows.
In the first embodiment, the varnish treatment is the dripping impregnation varnish treatment. However, the immersion impregnation varnish treatment may be performed, and the varnish 12 may be impregnated in a vacuum container. According to this, since the varnish 12 is impregnated in a reduced pressure state, the varnish 12 is surely secured to a narrow space between the bonded electric wires 6 of the winding 7, between the winding 7 and the slot 2a, and between the slot insulator 3 and the slot 2a. Impregnated. In the immersion impregnation varnish treatment, the stator 1 is immersed and impregnated in a container in which the varnish 12 is accommodated. Inside, the varnish 12 impregnated in the stator 1 is cured by heating.

In the above-described embodiment, the slot insulator 3 and the wedge material 11 are configured such that the synthetic resin 5 is applied to, for example, one surface of the film or synthetic paper that is the sheet material 4. The synthetic resin 5 may be applied to both sides of the paper.
The slot insulator 3 and the wedge material 11 are configured by applying the synthetic resin 5 to the sheet material. However, it is not necessary to apply the synthetic resin 5 to the sheet material, and the synthetic resin formed by the sol-gel method is formed into a sheet shape. However, the slot insulator 3 and the wedge member 11 may be configured by using them themselves.

  Further, the synthetic resin 5 is applied to the sheet material 4, but the sheet material used as the slot insulator 3 is a film such as polyethylene terephthalate, polyethylene naphthalate or polyphenylene sulfide, or a synthetic paper such as aramid. Or it is a bonding material with other sheet | seat materials, and it is good also as a structure by which the 1st filler and the 2nd filler are previously contained in the raw material of these films or synthetic paper.

In the above embodiment, the second filler is deposited by a sol-gel method using a metal alkoxide (tetraethoxysilane) as a raw material, but carbon black or alumina is contained as a second filler in the resin. May be.
In the above you施例, slot insulators 3, bonding wires 6, a configuration used contain a first filler and the second filler in all parts of the wedge member 11 and the varnish 12, all It is not necessary to use it by being contained in one member, and for example, it may be used by being contained in one member or two or more members.

1 is a partial longitudinal sectional view of a stator showing a first embodiment of the present invention. Partial cross-sectional perspective view of slot portion Diagram showing coil end Cross section of bonded wire Chart showing the sol-gel method Diagram showing the change in thermal conductivity when filled with carbon black Figure 6 corresponds diagram when alumina was added to Figure showing the change in thermal conductivity depending on the particle size ratio of boron nitride and alumina FIG. 6 equivalent view showing the second embodiment of the present invention 7 equivalent diagram Fig. 1 equivalent diagram showing conventional technology

Explanation of symbols

In the drawings, 1 is a stator, 2 is an iron core, 2a is a slot, 3 is a slot insulator, 4 is a sheet material, 5 is a synthetic resin, 6 is an adhesive wire, 7 is a winding, 10 is an adhesive layer, and 11 is a wedge. The material, 12 indicates varnish.

Claims (4)

Boron nitride or magnesium oxide as a first filler having a thermal conductivity of at least 1.0 W / mK as a treatment varnish for a winding of a rotating electrical machine, and a particle size of 0 as compared with the first filler Using a resin that uniformly contains carbon black or alumina as the second filler that is 15 times or less ,
The rotating electrical machine, wherein the second filler is precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material . Boron nitride or magnesium oxide as a first filler having a thermal conductivity of at least 1.0 W / mK as slot insulator inserted between the winding of the rotating electrical machine and the iron core for ground insulation A single sheet material or other sheet material containing resin uniformly containing carbon black or alumina as the second filler having a particle size of 0.15 times or less as compared with the first filler used in the bonding material and,
The rotating electrical machine, wherein the second filler is precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material . As a magnet wire for a winding of a rotating electric machine, an adhesive electric wire formed by applying an adhesive layer of a B stage on the surface of an enameled wire is used. Uniformly containing boron nitride or magnesium oxide as the first filler and carbon black or alumina as the second filler having a particle size of 0.15 times or less that of the first filler and,
The rotating electrical machine, wherein the second filler is precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material . As a wedge material of a rotating electrical machine, boron nitride or magnesium oxide as a first filler having a thermal conductivity of at least 1.0 W / mK or more, and the particle size is 0.15 times that of the first filler. used in a second filler as carbon black or alumina and uniformly containing resin was single sheet material, or, in the bonding material with the other sheet material or less,
The rotating electrical machine, wherein the second filler is precipitated and dispersed by a sol-gel method using a metal alkoxide as a raw material .

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