JP2003158842A - Rotary machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotary machine wherein heat generated in coils is likely conducted to a stator and radiativity is enhanced. SOLUTION: The rotary machine includes a stator core formed by laminating a plurality of electromagnetic steel plates. Conductors are wound around slots of the stator core to form coils. A thermosetting resin containing inorganic ceramic filler is impregnated and set up between the conductors of the coils, between the conductors and the slots, and at coil ends. A thermosetting resin whose coefficient of thermal conductivity is not less than 0.6 W/m.K is used for the thermosetting resin. Filler powder whose coefficient of thermal conductivity is not less than 5 W/m.K is used for the filler.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotating machine using an insulating material having good heat radiation. 2. Description of the Related Art By efficiently radiating heat generated by a stator coil, it is possible to realize a long-life, high-efficiency rotating machine with little reduction in life due to heat generation. Conventionally, it is common to increase the surface area of the frame around the stator using radiation fins, to perform forced air cooling using a fan or the like, or to perform liquid cooling using a cooling liquid passage provided in the frame. . There are also those that directly cool the core coil inside the rotating machine with oil, and those that let the internal heat be released to the outside with a heat pipe, but the number of parts increases because the inside of the rotating machine is directly cooled, The structure becomes complicated, and new issues such as securing reliability also arise. [0003] The surface of the coil is electrically insulated in order to allow a current to flow through the coil as a heat source. However, it is also necessary to electrically insulate the coil from a stator core made of an electromagnetic steel sheet or the like around which the coil is wound. There is. For this reason, after a conductor having an insulating coating provided around a conductor is incorporated into a stator, a resin or a resin containing a filler of inorganic ceramics is injected to increase thermal conductivity and suppress electromagnetic vibration. JP-A-10-283
In Japanese Patent No. 45, in a stator coil of a high-pressure rotating machine, an impregnated resin containing a filler of inorganic ceramics is impregnated in a non-impregnated coil under vacuum pressure to constitute a stator coil. Further, in Japanese Patent Application Laid-Open No. 2000-139046, in a rotating machine having a rotor in which a rotor is formed of a permanent magnet, an impregnated resin mixed with a filler of inorganic ceramics is used between a stator and a conductor, and between a stator and a housing. Impregnation improves heat dissipation, and prevents permanent magnets constituting the rotor from being demagnetized by heat generated from the coils.
Further, in Japanese Patent Application Laid-Open No. 2000-297204, a mixture of an epoxy resin composition having improved storage stability and high-temperature electrical characteristics and a filler of inorganic ceramics is used as a coil insulating material. [0004] With the increase in the output of the rotating machine, the current of the coil of the stator increases, the copper loss and the iron loss increase, and the calorific value increases. Temperature rise becomes remarkable. Therefore, between the stator core and the coil, in order to transfer heat generated from the coil to the stator core, a filler made of inorganic ceramics is filled, and the resin having improved thermal conductivity is electrically insulated. However, it is difficult to infiltrate the filler of the inorganic ceramics together with the resin into the gap between the conductive wires constituting the coil. If the insulating layer is formed only of resin between the conductors, the general thermal conductivity of the resin is 0.2 W / m ·
Since it is about K, there is a problem that thermal conductivity is hindered by the insulating layer between the conductive wires, and the heat generated in the coil is hardly dissipated. Also, to increase the thermal conductivity of the impregnated resin,
When a large amount of filler of inorganic ceramics is mixed with the resin, the viscosity of the impregnated resin increases, so that it becomes difficult for the impregnated resin to uniformly enter the inside of the slot, voids are formed, and electric insulation and thermal conductivity are adversely affected. There is also a problem. An object of the present invention is to provide a rotating machine that facilitates transmission of heat generated in a coil to a stator and has good heat radiation. [0005] The gist of the present invention to achieve the above object is as follows. [0006] A stator core in which a plurality of electromagnetic steel sheets are laminated is provided. A coil is formed by winding a conductor around slots of the stator core, and an inorganic ceramic material is provided between conductors of the coil, between conductors and slots, and at a coil end. In a rotating machine which is solidified by impregnating a thermosetting resin containing a filler, a thermosetting resin having a thermal conductivity of 0.6 W / m · K or more is used as the thermosetting resin, A rotating machine characterized by using filler powder having a thermal conductivity of 5 W / m · K or more as a filler. Hereinafter, a rotating machine according to the present invention will be described in detail. The rotating machine according to the present invention is, for example, a high-speed motor such as a machine tool having a high-speed rotating shaft, a generator / motor incorporated in an engine of a cogeneration system, or a generator mounted on an output shaft of an engine of a hybrid vehicle. The present invention is applied to a motor, a generator incorporated in a turbocharger for recovering exhaust gas energy, or a generator provided in an energy recovery device. The thermosetting resin in the present invention refers to a cured resin in which a resin component therein forms a crosslinked structure by heating. Specific examples of the resin component include cured products such as an unsaturated polyester resin, an epoxy resin, an acrylic resin, a phenol resin, a melamine resin, a urea resin, and a urethane resin. In particular, an epoxy resin having excellent insulation and heat resistance can be used. These resin components are monomers,
Crosslinking agents, flexibilizers, diluents, modifiers and the like can be included. It is important that the thermosetting resin of the present invention has a thermal conductivity of 0.6 W / m · K or more. If it is less than 0.6 W / m · K of the resin itself, the thermal resistance of the resin component has a great effect, and even if an inorganic ceramic filler powder described later is added, the effect of improving the thermal conductivity is small. Therefore, the heat radiation of the rotating machine is not so improved. Examples of the thermosetting resin having a thermal conductivity of 0.6 W / m · K or more include the following thermosetting resins. That is, the thermosetting resin is characterized by having an anisotropic structure in the resin component contained in the thermosetting resin. Particularly preferably, the anisotropic structural unit constituting the anisotropic structure has a covalent bond,
A thermosetting resin characterized in that the maximum value of the diameter of the anisotropic structural unit is 400 nm or more, and the proportion of the anisotropic structure contained in the resin component is 25 vol% or more. The anisotropic structure is a structure having a microscopic arrangement. For example, a crystal phase, a liquid crystal phase, and the like correspond. Whether such a structure exists in the resin or not can be easily determined by observation with a polarizing microscope. That is, in the observation in the crossed Nicols state, it is possible to determine by observing interference fringes due to the depolarization phenomenon. As one means for forming an anisotropic structure,
Introducing a mesogen into the monomer structure. The mesogen is a functional group that may exhibit liquid crystallinity, and specific examples include biphenyl, phenylbenzoate, azobenzene, stilbene, and derivatives thereof. An example of such a resin is 4- (oxiranylmethoxy) benzoic acid-4,4 '-[1,8-octanediylbis (oxy)] bisphenol ester (hereinafter Tw) as an epoxy resin monomer.
8) shows the properties of a resin plate using 4,4′-diaminodiphenylmethane (hereinafter, DDM) as a curing agent for an epoxy resin. Tw8 and DDM are melted at 160 ° C. in advance, mixed, poured into a mold that has been subjected to a mold release treatment, and heated and cured to form a 5 mm thick thermosetting resin resin plate (Tw8 / D8).
DDM) was synthesized. The mixing ratio of the epoxy resin monomer and the curing agent was stoichiometric, the curing temperature was 160 ° C., and the curing time was 10 hours. When this resin plate was inserted between two polarizing plates in a crossed Nicols state and observed with a microscope, interference fringes due to depolarization were observed. Therefore, it is understood that this resin plate has an anisotropic structure. The anisotropic structural unit of this resin plate was observed by TEM. At the time of observation, RuO4 was used as a staining agent, and observation was performed at a magnification of 30,000 times. The maximum value of the diameter of the anisotropic structure unit is 1600 nm, and the ratio of the anisotropic structure is 4
It was 0 vol%. In addition, the boundary of the portion of the anisotropic structure was determined by performing image processing on a photographed image by adjusting contrast. FIG. 1 is a schematic diagram in which a portion having an anisotropic structure is determined from a photograph taken. Since the anisotropic structure is also distributed in the depth direction, the ratio of the anisotropic structure was calculated as the ratio of the area of the anisotropic structure to the area of the entire photograph. The maximum value of the diameter of the anisotropic structural unit was a measured value of the longest part of each anisotropic structural unit. When the thermal conductivity of this resin plate was measured,
It exhibited a high thermal conductivity of 0.83 W / m · K. The thermal conductivity is a value in the thickness direction of the sample according to the flat plate comparison method. The average temperature of the sample at the time of measurement was about 80 ° C., and borosilicate glass was used as a standard sample. The thermosetting resin according to the present invention achieves an extremely high thermal conductivity by containing the resin as described above and further including an inorganic ceramic filler powder having a thermal conductivity of 5 W / m · K or more. it can. With a filler powder of less than 5 W / m · K, the effect of improving the thermal conductivity of the resin is extremely small. Examples of the inorganic ceramic used include crystalline silica, alumina, magnesium oxide, beryllium oxide, tin oxide, boron nitride, aluminum nitride, silicon nitride, silicon carbide, aluminum fluoride, calcium fluoride and the like. Above all, by using a filler powder containing alumina, tin oxide, boron nitride, aluminum nitride, and silicon nitride as main components, a resin having both high thermal conductivity and high insulating properties can be obtained. The content of the inorganic ceramics in the thermosetting resin is preferably 20% by volume or more. The thermosetting resin is provided with a stator core in which a plurality of electromagnetic steel sheets are laminated, and a conductor is wound around a slot of the stator core to form a coil. By using as a thermosetting resin of a rotating machine solidified by impregnating a thermosetting resin containing a filler of inorganic ceramics between the slots and the coil end, the heat radiation from the coil is improved. The rotor that enters the stator may be a rotor having a permanent magnet, a rotor for a reluctance motor that does not use a permanent magnet, or a cage rotor for an induction machine. Hereinafter, embodiments of the rotating machine according to the present invention will be described, and the present invention will be specifically described. (Embodiment 1) FIG. 2 shows a cross section of a stator of a rotating machine. The stator 1 includes a stator core 3 having a plurality of slots 4 and a plurality of coils 2 inserted into the slots 4 of the stator core 3.
And the impregnated resin 5 impregnated in the voids. The stator core 3 has a cylindrical shape formed by laminating thin ring-shaped silicon steel sheets. On the inner peripheral surface side of the stator core 3, twelve axially continuous slots 4 are provided in the circumferential direction. Each of the slots 4 has a coil 2 composed of a bundle of conductors provided with an insulating coating around the conductor.
Is inserted. And, as mentioned above, slot 4
The coil 2 inserted into the resin impregnation tank together with the stator core 3 is impregnated with the impregnated resin 5 under vacuum and pressure.
Then, it is set in a curing furnace and cured by heating. As the impregnated resin 5, crystalline silica (average particle diameter: 1 μm, thermal conductivity: 5.4 W / m · K) was added to Tw8 / DDM.
A thermosetting resin added with 0% by volume was used. Although not shown in FIG. 1, the rotor is provided on the inner peripheral side of the stator core 3 so as to be rotatable through a gap, a so-called air gap. In the present example, a rotor having a permanent magnet was installed in a stator to produce a rotating machine. The stator coil loss of this rotating machine is about 1 kW
When the coil temperature was measured under the following operating conditions, 133
℃ and excellent in heat dissipation. The measurement of the coil temperature was performed by a method of estimating the coil temperature from a change in the resistivity of the conductive wire. Table 1 shows the conditions and results of this example. [Table 1] (Comparative Example 1) BisA / D as impregnated resin
Crystalline silica (average particle diameter 1 μm, thermal conductivity 5.
A rotating machine similar to that of Example 1 was manufactured using the same material as that of Example 1 except that a thermosetting resin to which 4 W / m · K) was added at 40% by volume was used. The thermal conductivity of the resin component of the impregnated resin is 0.2 W / m · K. The coil temperature of this rotating machine was measured in the same manner as in Example 1. Its temperature is 153 ° C. and B
When isA / DDM is used as the impregnating resin, the temperature is high,
Heat dissipation was poor. Table 2 shows the conditions and results of this comparative example.
Are shown together. [Table 2] (Example 2) As impregnating resins, Tw8 and B
An epoxy resin monomer in which isA is mixed at a weight ratio of 70:30 and DDM are combined, and a thermosetting resin to which 40% by volume of crystalline silica (average particle diameter of 1 μm, thermal conductivity of 5.4 W / m · K) is added. A rotating machine similar to that of Example 1 was manufactured using the same materials as in Example 1 except for the use. The thermal conductivity of the resin component of the impregnated resin is 0.65 W / m · K. The coil temperature of the rotating machine was measured in the same manner as in Example 1. The temperature was as low as 135 K, and the heat dissipation was excellent. Table 1 shows the conditions and results of this example.
Are shown together. (Comparative Example 2) As an impregnated resin, an epoxy resin monomer in which Tw8 and BisA were mixed at a weight ratio of 50:50 and DDM
And the same material as in Example 1 except that a thermosetting resin to which 40% by volume of crystalline silica (average particle diameter 1 μm, thermal conductivity 5.4 W / m · K) is added is used. A similar rotating machine was manufactured. The thermal conductivity of the resin component of the impregnated resin is 0.51 W / m · K. The coil temperature of the rotating machine was measured in the same manner as in Example 1. The temperature is as high as 152 K, which indicates that the heat dissipation is poor. Table 2 shows the conditions and results of this comparative example. FIG. 3 shows the relationship between the coil temperature of each rotating machine and the thermal conductivity of the resin component of the impregnated resin obtained in Examples 1 and 2 and Comparative Examples 1 and 2. As can be seen from FIG. 3, the thermal conductivity of the resin component of the impregnated resin is 0.6 W / m.
・ It was found that the coil temperature of the rotating machine suddenly dropped when the temperature became K or more. (Example 3) A rotating machine similar to that of Example 1 was manufactured using the same material as that of Comparative Example 1 except that alumina (average particle diameter 3 μm, thermal conductivity 30 W / m · K) was used as the filler powder to be added. did. The coil temperature of this rotating machine was measured in the same manner as in Example 1. The temperature was as low as 149K, and the heat dissipation was excellent. Table 1 shows the conditions and results of this example.
Are shown together. (Comparative Example 3) The same rotation as in Example 1 was performed using the same material as in Example 1 except that the filler powder to be added was fused silica (average particle diameter 3 μm, thermal conductivity 1.4 W / m · K). Machine was made. The coil temperature of this rotating machine was measured in the same manner as in Example 1. The temperature is as high as 167K, which indicates that the heat dissipation is poor. Table 2 shows the conditions and results of this comparative example. FIG. 4 shows the relationship between the coil temperature of each rotating machine and the thermal conductivity of the filler obtained in Comparative Examples 1, 3, and 3 above. As can be seen from FIG. 4, it was found that when the thermal conductivity of the filler powder was 5 W / m · K or more, the coil temperature of the rotating machine rapidly decreased. According to the present invention, it is possible to obtain a rotating machine having extremely excellent heat dissipation. As a result, the cooling efficiency is improved as compared with the conventional insulation method, so that the rotating machine can be reduced in size and increased in capacity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing an example of the observation result of a thermosetting resin in the present invention by TEM. FIG. 2 is a sectional structural view of a stator according to the present invention. FIG. 3 is a graph showing the relationship between the thermal conductivity of a resin component used for the impregnated resin and the coil temperature of a rotating machine using the impregnated resin in the present invention. FIG. 4 is a graph showing the relationship between the thermal conductivity of a filler added to the impregnated resin and the coil temperature of a rotating machine using the impregnated resin in the present invention. [Description of Signs] 1 ... stator, 2 ... coil, 3 ... stator core, 4 ... slot, 5 ... impregnated resin.

Continuation of front page    (72) Inventor Yoshitaka Takezawa             7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture             Hitachi, Ltd., Hitachi Laboratory (72) Inventor Masaki Akatsuka             7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture             Hitachi, Ltd., Hitachi Laboratory F term (reference) 5H603 AA09 AA11 BB01 BB02 BB05                       CA01 CB02 CB03 CC01 CC11                       CD02 EE10 EE13 FA08 FA11                       FA24                 5H604 AA03 AA08 BB01 BB03 BB08                       BB14 CC01 CC05 CC11 DA06                       DA15 DA23 DB02 PB02 QB14                 5H615 AA01 BB01 BB02 BB05 BB14                       PP01 PP14 SS05 SS41 SS44                       TT23 TT34

Claims (1)

Claims: 1. A stator core comprising a plurality of electromagnetic steel sheets laminated, a coil is formed by winding a conductor around a slot of the stator core, and a coil is formed between conductors of the coil, a conductor and a slot. In a rotating machine in which a thermosetting resin containing a filler of inorganic ceramics is impregnated and solidified in a space and a coil end, the heat conductivity of the resin itself is 0.6 W / m · K or more as the thermosetting resin. A rotating machine using a thermosetting resin and using a filler powder having a thermal conductivity of 5 W / m · K or more as the filler.