Thermosetting resin composition and stator

Abstract

This invention provides a technology that achieves both insulation and inter-coil filling properties when filling the space between the stator and the coil with a resin composition. [Solution] The stator 4 has a stator core 41 having a plurality of teeth 7 and a plurality of slots 8 formed alternately in the circumferential direction, a coil 9 wound around the slots and housed in the slots, and a sealing member (resin sealing part 65) provided in the slots to seal the coil. The thermosetting resin composition used to form the sealing member (resin sealing part) comprises an epoxy resin, a curing agent, and an inorganic filler, wherein the D90 in the particle size distribution of the inorganic filler is 40 μm or more and 70 μm or less, and the D10 is 0.1 μm or more and 1.0 μm or less.

Description

Technical Field

[0001] The present invention relates to a thermosetting resin composition and a stator.

Background Art

[0002] As a technique using a resin material for a stator core, there is one described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2003-284277). In this document, in a rotating electric machine having a stator in which a plurality of electromagnetic steel sheets are laminated and a plurality of coils are wound around the stator core at a predetermined interval, a rotor rotatably held with respect to the stator, and a cooling frame for fixing the stator, a high thermal conductivity composite material in which a slot serving as a winding portion of the stator is formed of a thermosetting resin having an anisotropic structure in a resin component is disposed. With such a configuration, it is said that a rotating electric machine in which heat generated by the coil is easily transmitted and has good heat dissipation is provided.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there are cases where a resin composition, which is an insulating member, is filled between a coil accommodated in a slot of a stator and the stator, and both insulation and filling between coils are required.

[0005] The present invention has been made in view of such a situation, and an object thereof is to provide a technique that achieves both insulation and filling between coils when a coil is disposed in a slot and a resin composition is filled between the stator and the coil.

Means for Solving the Problems

[0006] The present invention provides the following technologies. <1> A stator having a stator core having a plurality of teeth and a plurality of slots formed alternately in the circumferential direction, a coil wound around the slots and housed in the slots, and a sealing member provided in the slots to seal the coil, wherein a thermosetting resin composition is used to form the sealing member, The thermosetting resin composition is Epoxy resin and Hardener and It contains an inorganic filler, A thermosetting resin composition in which the particle size distribution of the inorganic filler has a D90 of 40 μm or more and 70 μm or less, and a D10 of 0.1 μm or more and 1.0 μm or less. <2> The ratio of D90 to D10 in the particle size distribution, D90 / D10, is 100 or more and 300 or less. <1> The thermosetting resin composition described in [reference]. <3> The ratio of D90 to D50 in the particle size distribution, D90 / D50, is 4 or more and 8 or less. <1> or <2> The thermosetting resin composition described in [reference]. <4> The amount of the inorganic filler is 90% by mass or more and 93% by mass or less of the total amount of the thermosetting resin composition. <1> ~ <3> A thermosetting resin composition according to any one of the following. <5> The inorganic filler comprises at least one selected from the group consisting of alumina, fused silica, and crystalline silica. <1> ~ <4> A thermosetting resin composition according to any one of the following. <6> The inorganic filler contains 60% by mass or more of alumina with respect to the entire thermosetting resin composition. <4> The thermosetting resin composition described in [reference]. <7> The gel time is between 40 seconds and 100 seconds. <1> ~ <6> A thermosetting resin composition according to any one of the following. <8> The thermal conductivity of the cured product of the thermosetting resin composition is 3.2 W / mK or higher. <1> ~ <7> A thermosetting resin composition according to any one of the following. <9> The epoxy resin comprises at least one selected from the group consisting of biphenyl-type epoxy resins, bisphenol-type epoxy resins, stilbene-type epoxy resins, novolac-type epoxy resins, polyfunctional epoxy resins, phenol aralkyl-type epoxy resins, and naphthol-type epoxy resins. <1> ~ <8> A thermosetting resin composition according to any one of the following. <10> The glass transition temperature is 175°C or higher. <1> ~ <9> A thermosetting resin composition according to any one of the following. <11> A stator comprising: a stator core having a plurality of teeth and a plurality of slots formed alternately in the circumferential direction; a coil wound around the slots and housed in the slots; and a sealing member provided within the slots to seal the coil, The sealing member, <1> ~ <10> A stator comprising a cured product of the thermosetting resin composition described in any one of the above. [Effects of the Invention]

[0007] According to the present invention, when a coil is placed in a slot and a resin composition is filled between the stator and the coil, a technology is provided that can achieve both insulation and inter-coil filling properties. [Brief explanation of the drawing]

[0008] [Figure 1] This is a cross-sectional view of the motor perpendicular to its rotation axis. [Figure 2] This is a longitudinal cross-sectional view of the motor in the direction of its rotation axis. [Figure 3] This is a magnified view of the area around the slot. [Figure 4] This is a cross-sectional view showing the inside of the slot. [Modes for carrying out the invention]

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are denoted by similar reference numerals, and the description thereof will be omitted as appropriate. In this specification, the numerical range "a to b" represents "a or more and b or less" unless otherwise specified.

[0010] <Summary> In this embodiment, in the stator of a rotating electric machine such as a motor, by defining the particle size distribution (D90, D10, etc.) of the inorganic filler contained in the thermosetting resin composition used to form the sealing member provided by sealing the coil in the slot, a technique that achieves both insulation and coil filling performance is provided.

[0011] <Motor> FIG. 1 schematically shows a cross-sectional view in a direction perpendicular to the rotation axis direction of the motor 100. FIG. 2 schematically shows a cross-sectional view in the rotation axis direction of the motor 100. FIG. 3 is an enlarged view of the slot periphery (region X in FIG. 1), and schematically shows a cross-sectional view of a portion where the coil 9 protrudes from the end of the slot 8. FIG. 4 is a view showing the inside of the slot 8, and is a cross-sectional view taken along the line A-A in FIG. 3.

[0012] The motor 100 includes a case 1, a rotor 2, a stator 4, and a coil 9 housed inside the case 1.

[0013] <Case> The case 1 is configured to have a cylindrical portion 1a and side plate portions 1b and 1c that close both axial ends of the cylindrical portion 1a. As the material of the case 1, for example, an aluminum alloy (cast casting), a resin material, or a combination thereof can be used.

[0014] <Rotor> As shown in FIGS. 1 and 2, the rotor 2 is housed inside the case 1. At the center of the rotor 2, as shown in FIG. 2, a rotation shaft 3 is attached as a figure output shaft. Both ends of the rotation shaft 3 are supported by the side plate portions 1b and 1c via bearings 3a, respectively. Thereby, the rotor 2 is rotatable about the rotation shaft 3.

[0015] The rotor 2 has permanent magnets 5 built into it. Specifically, as shown in Figure 1, multiple (eight in this case) permanent magnets 5 are arranged at equal intervals on the same circumference. At this time, the magnetic poles of adjacent permanent magnets 5 are set to be opposite to each other.

[0016] <Stata> The stator 4 has a stator core 41 and coils 9 sealed in slots 8. The stator core 41 is formed by stacking and tightly fixing multiple electromagnetic steel sheets in the axial direction. As shown in Figure 1, when viewed from the axial end, it has an annular yoke portion 6 and multiple tooth portions 7 extending from the yoke portion 6 toward the rotor 2 side (inner circumference side). The multiple tooth portions 7 are arranged at equal intervals in the circumferential direction. Here, as an example, as shown in Figure 1, 24 tooth portions 7 are provided. Slots 8 are provided between each tooth portion 7. In addition, the tooth portions 7 are covered with a thin resin layer 50 formed by encircling them with a resin composition. The axial length of the stator 4 (stator core 41) is, for example, 100 mm to 200 mm. A motor 100 having a stator 4 of this size is suitable for use as a drive motor in automobiles.

[0017] <coil> The coil 9 is a U-shaped flat wire and is wound so as to be housed in two spaced-apart slots 8 that straddle the teeth portion 7. Here, the coil 9 is housed in a distributed winding within a liner member 20 positioned in the slots 8. The coil 9 has a coil body made of a good conductor such as copper with a rectangular cross-section, and a resin coating layer that covers the surface of the coil body. The resin coating layer can be made of the same material as the resin material described later for the resin sealing portion 65 and the resin layer 50.

[0018] <Teeth Department> The teeth section 7 is provided in correspondence with the permanent magnet 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to the attraction and repulsion with the corresponding permanent magnet 5.

[0019] The teeth portion 7 has a larger circumferential width on the outer circumference side and a smaller width on the inner circumference side, tapering towards the inner circumference. At the inner end of the teeth portion 7, opposing teeth tip portions 71 are formed along the circumferential direction to reduce the width of the slot 8.

[0020] <Slot> Slot 8 is the space between adjacent tooth portions 7, and as shown in Figures 3 and 4, it is provided such that the inner wall surfaces 72 of opposing tooth portions 7 along the radial direction are parallel. The space between the tips 71 of the tooth portions forms the inner circumferential opening of slot 8. Slot 8 has a plurality of coils 9 arranged on the outer circumferential side (yoke portion 6 side) and a resin sealing portion 65 that fills the space in slot 8 excluding the coils 9 and the resin layer 50.

[0021] <Resin layer> As shown in Figures 3 and 4, the resin layer 50 integrally surrounds the periphery of the teeth portion 7 with the resin composition and has a teeth inner surface resin layer 51 that covers the inner wall surface 72 of the teeth portion 7, a teeth outer surface resin layer 52 that covers the upper surface 75a and lower surface 75b of the teeth portion 7, and a yoke inner surface resin layer 53 that covers the inner wall surface 62 of the yoke portion 6.

[0022] The resin layer 50 covers the teeth portion 7 in a thin, encircling manner by insert molding, thereby tightly fixing the multiple laminated electromagnetic steel sheets in the stator 4, more specifically in the teeth portion 7. Note that the resin layer 50 does not necessarily need to encircle the teeth portion 7 in a thin manner, and the outer tooth resin layer 52 may be omitted. Having the inner tooth resin layer 51 and the inner yoke resin layer 53 ensures insulation between the coil 9 and the inner wall surfaces of the slot 8 (the inner wall surface 72 of the teeth portion 7 and the inner wall surface 62 of the yoke portion 6), particularly in the process of housing the coil 9 in the slot 8 and forming the resin sealing portion 65.

[0023] The thickness of the resin layer 50 is, for example, 50 μm or more and 500 μm or less. The lower limit of the thickness is preferably 100 μm or more, and more preferably 150 μm or more. The upper limit of the thickness is preferably 400 μm or less, and more preferably 300 μm or less. The thicknesses of the inner surface resin layer 51 of the teeth, the outer surface resin layer 52 of the teeth, and the inner surface resin layer 53 of the yoke may be the same or different. The lower limit of the thickness is preferably within the above range from the viewpoint of ensuring the fluidity of the resin composition in the extremely narrow space between the mold (mold core) and the wall surface of the slot 8 with respect to the stator axis length (i.e., the thickness of the stator 4) during insert molding. In a structure in which the coil 9 is wound around the teeth portion 7 and placed in the slot 8, it is preferable to set the upper limit of the thickness within the above range from the viewpoint of improving the efficiency of space utilization within the slot 8 and ensuring the freedom of the usable coil 9 size and performance such as magnetic flux density.

[0024] <Materials for the resin layer> The resin material used in the resin layer 50 can be the same as the resin material described later for the resin sealing portion 65.

[0025] <Resin sealing part> The resin sealing portion 65 is provided on the inner circumference side of the slot 8 and seals the coil 9. The resin sealing portion 65 is provided by insert molding.

[0026] <Materials for resin encapsulation> The resin composition of the resin sealing portion 65 preferably includes a thermosetting resin (A), a filler (B), and a curing agent (C).

[0027] [Thermosetting resin (A)] Examples of thermosetting resins (A) include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins. One of these may be used alone as thermosetting resin (A), or two or more may be used in combination. In particular, from the viewpoint of having high insulating properties, epoxy resin, phenolic resin, and phenoxy resin are preferred as the thermosetting resin (A). From the viewpoint of ensuring flow in extremely narrow areas during molding, epoxy resin is especially preferred.

[0028] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexydiene bisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol group methane type novolac type epoxy resin, and tetraphenol group ethanol. Examples include novolac epoxy resins such as n-type novolac epoxy resins and novolac epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl epoxy resins; arylalkylene epoxy resins such as xylylene epoxy resins and biphenyl aralkyl epoxy resins; naphthalene epoxy resins such as naphthylene ether epoxy resins, naphthol epoxy resins, naphthalenediol epoxy resins, bifunctional or tetrafunctional epoxy naphthalene resins, binaphthyl epoxy resins, and naphthalene aralkyl epoxy resins; anthracene epoxy resins; phenoxy epoxy resins; dicyclopentadiene epoxy resins; norbornene epoxy resins; adamantane epoxy resins; and fluorene epoxy resins. One of these may be used alone, or two or more may be used in combination.

[0029] Among epoxy resins, it is preferable to use one or more selected from the group consisting of bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, arylalkylene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, and dicyclopentadiene-type epoxy resins, from the viewpoint of further improving heat resistance and insulation reliability.

[0030] Examples of phenolic resins include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, as well as resol-type phenolic resins. One of these may be used alone, or two or more may be used in combination. Among phenolic resins, phenol novolac resin is preferred.

[0031] The content of thermosetting resin (A) is preferably 1% by mass or more, and more preferably 3% by mass or more, relative to the total amount of resin composition of the resin sealing portion 65. Furthermore, the content is preferably 10% by mass or less, and more preferably 5% by mass or less, relative to the total amount of resin composition of the resin sealing portion 65.

[0032] When the content of thermosetting resin (A) is equal to or greater than the lower limit, the handling of the entire resin composition of the resin sealing portion 65 is improved, making it easier to form the resin sealing portion 65, and also improving the strength of the resin sealing portion 65.

[0033] If the content of thermosetting resin (A) is below the above upper limit, the coefficient of linear expansion and elastic modulus of the resin-sealed portion 65 will be further improved, and the thermal conductivity will be further improved.

[0034] [Filler (B)] In this embodiment, the filler (B) is used from the viewpoint of improving the thermal conductivity of the resin-sealed portion 65 and obtaining strength.

[0035] As the filler (B), an inorganic filler is preferred, and a thermally conductive filler is particularly preferred. More specifically, as the filler (B), from the viewpoint of balancing thermal conductivity and electrical insulation, examples include silica, alumina, boron nitride, aluminum nitride, and silicon carbide. These may be used individually or in combination of two or more. Among these, it is preferable that the filler (B) contains at least one selected from the group consisting of alumina and silica (fused silica, crystalline silica).

[0036] The content of filler (B), that is, the content of the inorganic filler described above, is 90% by mass or more and 93% by mass or less, relative to the total amount of the resin composition (the entire thermosetting resin composition). By setting the content of the inorganic filler within the above range, the fluidity and filling properties of the resin composition during molding can be more effectively improved. More specifically, from the viewpoint of achieving the thermal conductivity described later, it is preferable that the lower limit be 90% by mass or more. On the other hand, from the viewpoint of fluidity and filling properties, it is preferable that it be 93% by mass or less.

[0037] The inorganic filler preferably contains 60% by mass or more of alumina relative to the entire thermosetting resin composition, more preferably 65% ​​or more, and even more preferably 70% or more. This makes it possible to increase the thermal conductivity of the resin-sealed portion 65 (i.e., the cured product of the thermosetting resin composition).

[0038] [Hardening agent (C)] When using an epoxy resin or a phenolic resin as the thermosetting resin (A) in the resin composition, it is preferable to further include a curing agent (C). As the curing agent (C), one or more selected from curing catalysts (C-1) and phenolic curing agents (C-2) can be used.

[0039] Examples of curing catalysts (C-1) include organometallic salts such as zinc naphthenate, cobalt naphthenate, tin octate, cobalt octate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; and 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole. Examples include imidazoles such as dazole and 2-phenyl-4,5-dihydroxymethylimidazole; organophosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium-tetraphenylborate, triphenylphosphine-triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenol compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid; and mixtures thereof. As the curing catalyst (C-1), one type, including its derivatives, can be used alone, or two or more types, including their derivatives, can be used in combination.

[0040] The content of the curing catalyst (C-1) is not particularly limited, but it is preferably 0.001% by mass or more and 1% by mass or less, relative to the total amount of the resin composition.

[0041] Furthermore, examples of phenolic curing agents (C-2) include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, trisphenolmethane-type novolac resin, naphthol novolac resin, and aminotriazine novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resin having a phenylene skeleton and / or biphenylene skeleton, and naphthol aralkyl resin having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins. These may be used individually or in combination of two or more types.

[0042] Among these, from the viewpoint of improving the glass transition temperature and reducing the coefficient of linear expansion, the phenolic curing agent (C-2) is preferably a novolac-type phenolic resin or a resol-type phenolic resin. The content of the phenolic curing agent (C-2) is not particularly limited, but is preferably 1% by mass or more, and more preferably 3% by mass or more, based on the total amount of the resin composition. Furthermore, the content is preferably 10% by mass or less, and more preferably 5% by mass or less, based on the total amount of the resin composition.

[0043] [Coupling agent (D)] The resin composition may also contain a coupling agent (D). The coupling agent (D) can improve the wettability of the interface between the thermosetting resin (A) and the filler (B).

[0044] The coupling agent (D) is not particularly limited, but it is preferable to use one or more coupling agents selected from, for example, epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate-based coupling agents, and silicone oil-type coupling agents.

[0045] The content of the coupling agent (D) is not particularly limited, but is preferably 0.05% by mass or more, and more preferably 0.1% by mass or more, based on 100% by mass of the filler (B). Furthermore, the content is preferably 3% by mass or less, and more preferably 2% by mass or less, based on 100% by mass of the filler (B).

[0046] [Phenoxy resin (E)] Furthermore, the resin composition may also contain phenoxy resin (E). By including phenoxy resin (E), the flexibility of the resin-sealed portion 65 can be improved, and the elastic modulus can be reduced, thereby improving the stress relaxation force of the resin-sealed portion 65.

[0047] Furthermore, the inclusion of phenoxy resin (E) increases viscosity, reducing fluidity and suppressing the formation of voids. Additionally, when the resin encapsulation portion 65 is used in close contact with a metal component, the adhesion between the metal and the cured resin composition can be improved.

[0048] Examples of phenoxy resins (E) include phenoxy resins having a bisphenol skeleton. Examples include phenoxy resins having a lipid, naphthalene skeleton, anthracene skeleton, and biphenyl skeleton. Furthermore, phenoxy resins with structures possessing multiple of these skeletons can also be used. The phenoxy resin (E) content is preferably, for example, 2% by mass or more and 5% by mass or less, based on the total amount of the resin composition.

[0049] [Wax (release agent)] The resin composition contains wax. This improves the release properties from the mold core 80 after molding. Examples of waxes include natural waxes such as carnauba wax, synthetic waxes such as montanic acid ester wax and polyethylene oxide wax, higher fatty acids such as zinc stearate and their metal salts, and paraffin. These may be used individually or in combination of two or more. In particular, it is preferable to include montanic acid ester wax.

[0050] When wax (release agent) is used, its content is preferably 0.01 to 0.3% by mass, more preferably 0.02 to 0.1% by mass, of the total resin molding material. This ensures that the effect of improving release properties is reliably obtained. As a result, the molding accuracy of the resin sealing portion 65 can be increased.

[0051] [Other ingredients] The resin composition may also contain adhesion aids, stress reducers, colorants, etc., to the extent that they do not impair the effects of the present invention.

[0052] <Particle size distribution of inorganic fillers> In the particle size distribution of the inorganic filler, D90 is between 40 μm and 70 μm, and D10 is between 0.1 μm and 1.0 μm. D90 and D10 are the particle sizes of the inorganic filler at which the cumulative frequencies, measured, for example, using a laser diffraction particle size distribution analyzer, are 90% and 10%, respectively, and in this embodiment, they are measured on a volume basis. Furthermore, the particle size distribution of the inorganic filler is determined by the ash content of the resin composition.

[0053] D10 can be considered an indicator of the proportion of fine powder; the smaller the value, the higher the proportion of fine powder, and the better the filling performance in narrow spaces such as gaps between coils. The lower limit of D10 is preferably 0.05 μm or more, and more preferably 0.1 μm or more. The upper limit of D10 is preferably 0.9 μm or less, and more preferably 0.8 μm or less. If D10 is too small, i.e., if there are too many fine fillers, it is desirable from the viewpoint of narrow-space filling ability, but on the other hand, thixotropy increases, the melt viscosity increases and fluidity tends to deteriorate. If D10 is too large, i.e., if there are too few fine fillers, the melt viscosity of the resin decreases, but the narrow-space filling ability tends to deteriorate. Therefore, by setting D10 within the above range, it is possible to balance narrow-space filling ability, fluidity, and melt viscosity.

[0054] D90 can be considered an indicator of the proportion of coarse powder; the larger the value, the smaller the proportion of coarse powder and the better the packing performance in narrow areas. The lower limit of D90 is preferably 45 μm or more, and more preferably 50 μm or more. The upper limit of D90 is preferably 65 μm or less, and more preferably 60 μm or less. If D90 is too small, i.e., if there is too little coarse powder, it is desirable from the viewpoint of narrow-space filling ability, but on the other hand, thixotropy increases, the melt viscosity increases, and fluidity tends to deteriorate. If D90 is too large, i.e., if there is too much coarse powder, the melt viscosity of the resin decreases, but the narrow-space filling ability tends to deteriorate. Therefore, by setting D90 within the above range, it is possible to balance narrow-space filling ability, fluidity, and melt viscosity.

[0055] In this way, by understanding the particle size distribution of the inorganic filler using two indicators, D10 and D90, the ratio of fine to coarse particles in the inorganic filler can be determined, enabling a balance between fluidity and narrow-space filling ability.

[0056] The ratio of D90 to D10 in the particle size distribution, D90 / D10, is between 100 and 300. The lower limit of the ratio D90 / D10 is preferably 125 or higher, more preferably 150 or higher. The upper limit is preferably 275 or lower, more preferably 250 or lower. By setting the ratio D90 / D10 within this range, both good fluidity and narrow-space filling properties can be achieved. More specifically, if D90 / 10 is too large, i.e., if there is too little coarse powder, the narrow-space filling performance improves, but on the other hand, the thixotropy increases, the melt viscosity increases, and the fluidity tends to deteriorate. If D90 / 10 is too small, i.e., if there is too much coarse powder, the melt viscosity of the resin decreases, but the narrow-space filling performance tends to deteriorate. Therefore, by setting D90 / 10 within the above range, it is possible to balance narrow-space filling performance, fluidity, and melt viscosity.

[0057] The ratio of D90 to D50 in the particle size distribution, D90 / D50, is between 4 and 8. A larger ratio of D90 / D50 indicates a smaller proportion of coarse powder and better packing performance. In particular, increasing the occupancy rate of the coil 9 narrows the space where the resin sealing portion 65 is provided (i.e., the space between the coil 9 and the wall surface of the slot 8), but even under such conditions, high packing performance can be achieved. The lower limit of the ratio D90 / D50 is preferably 4.5 or higher, and more preferably 5 or higher. The upper limit is preferably 7.5 or lower, and more preferably 7 or lower. If D90 / 50 is too high, i.e., if there is too little coarse powder, it is desirable from the viewpoint of narrow-space filling ability, but on the other hand, thixotropy increases, the melt viscosity increases and fluidity tends to deteriorate. Conversely, if D90 / 50 is too low, i.e., if there is too much coarse powder, the melt viscosity of the resin decreases, but the narrow-space filling ability tends to deteriorate. Therefore, by setting D90 / 50 within the above range, it is possible to balance narrow-space filling ability, fluidity, and melt viscosity.

[0058] <Physical properties of the resin-sealed part> The physical properties of the cured resin material constituting the resin sealing portion 65 are as follows, for example. The same applies to the physical properties of the cured resin material constituting the resin layer 50.

[0059] <Thermal conductivity> The thermal conductivity of the cured resin material of the resin sealing portion 65 is 3.2 W / mK or higher. The lower limit of the thermal conductivity is preferably 4.0 W / mK or higher, and more preferably 5.0 W / mK or higher. The upper limit of the thermal conductivity is not particularly limited, but a practical value is 15 W / mK. The desired thermal conductivity can be obtained by adjusting the content of the inorganic filler. By setting the thermal conductivity within the above range, the heat from the coil 9 can be effectively transferred to the stator core 41.

[0060] <Glass transition temperature Tg> The glass transition temperature Tg of the cured resin composition of the resin encapsulation part 65 is 175°C or higher, preferably 190°C or higher, and more preferably 200°C or higher. The glass transition temperature Tg of the cured resin is measured using a thermomechanical analyzer (TMA) under conditions such as a measurement temperature range of 0°C to 320°C and a heating rate of 5°C / min. By setting the glass transition temperature Tg within the above range, the motor 100 can be used at high temperatures, and the coil 9 becomes more resistant to heat generation, allowing for high-power operation. In particular, the operating temperature tends to increase with increasing power output of the stator 4. As described above, by increasing the thermal conductivity of the resin encapsulation part 65, the heat generated in the coil 9 can be efficiently conducted and dissipated to the stator core 41, and by setting the glass transition temperature Tg within the above range, the heat resistance of the resin can be increased, allowing for greater design flexibility and margin.

[0061] <Geltime> The gel time is 40 seconds or more and 100 seconds or less. From the viewpoint of improving the moldability of the resin composition and speeding up the molding cycle, the gel time of the resin composition is preferably 45 seconds or more, and more preferably 50 seconds or more. From the viewpoint of achieving a cured product with excellent curability, the gel time of the resin composition is preferably 100 seconds or less, and more preferably 75 seconds or less. The gel time can be measured by melting the resin composition on a hot plate heated to 175°C and then measuring the time (gel time) until it becomes tack-free while kneading it with a spatula.

[0062] <Minimum melt viscosity> The minimum melt viscosity is 1.0 Pa·s or more and 100.0 Pa·s or less. The minimum melt viscosity can be controlled by adjusting the type of thermosetting resin used and the amount of thermoplastic resin blended. For example, the lower limit of the minimum melt viscosity of the cured resin composition of the resin sealing part 65 is 1.0 Pa·s or more. If this value is exceeded, the filling performance will decrease, and voids or unfilled areas may occur.

[0063] The minimum melt viscosity of the cured resin composition of the resin encapsulation part 65 refers to the lowest viscosity exhibited by the phenolic resin composition when the cured product is melted by heating. More specifically, when the resin encapsulation part 65 is heated at a constant heating rate to melt the resin, the melt viscosity decreases with increasing temperature in the initial stage, and then increases with increasing temperature beyond a certain point. The minimum melt viscosity refers to the melt viscosity at such a minimum point. The minimum melt viscosity of the resin composition layer can be measured by the dynamic viscoelastic method.

[0064] The minimum melt viscosity varies depending on the size of the stator 4 (stator core 41). In the case of a small stator 4, the volume of the resin encapsulation part 65 is small, and generally, a lower viscosity is preferable considering the ability to fill narrow spaces. In the case of a large stator 4, the volume of the resin encapsulation part 65 is large, and if the viscosity is low, there is a tendency for many voids to be trapped, and it may not be possible to completely crush the voids with holding pressure, so the viscosity is adjusted to be somewhat higher.

[0065] <Method for producing resin compositions> Next, we will explain the method for producing the resin composition. For example, first, a mixture is obtained by mixing the aforementioned raw material components by known means. Furthermore, a kneaded product is obtained by melt-kneading the mixture. As for the kneading method, for example, an extruder such as a single-screw kneading extruder or a twin-screw kneading extruder, or a roll-type kneader such as a mixing roll can be used, but it is preferable to use a twin-screw kneading extruder. After cooling, the kneaded product can be made into a predetermined shape such as powder, granules, tablets, or sheets.

[0066] One method for obtaining a granular resin composition is to pulverize a mixture using a pulverizing device. Alternatively, the mixture may be formed into a sheet and then pulverized. Examples of pulverizing devices include hammer mills, stone mills, and roll crushers.

[0067] As a method for obtaining a granular or powdered resin composition, for example, a granulation method such as the hot-cut method can be used, in which a small-diameter die is installed at the outlet of a kneading device, and the molten kneaded material discharged from the die is cut to a predetermined length with a cutter or the like. In this case, after obtaining a granular or powdered resin composition by a granulation method such as the hot-cut method, it is preferable to degas the resin composition before its temperature drops too much.

[0068] The resin composition obtained in this embodiment contains an epoxy resin, a curing agent, and an inorganic filler. Since the inorganic filler content, the glass transition temperature of the cured product, and the thermal modulus of the cured product are all within the specific ranges described above, it is suitable for use as a resin sealing part 65 when sealing a coil 9 into a slot 8. This allows for the creation of a resin sealing part 65 with excellent workability when filling the resin composition, resin filling properties, and thermal history resistance of the cured product.

[0069] <Summary of Embodiments> The features of this embodiment can be summarized as follows: <1> A stator 4 having a stator core 41 having a plurality of teeth 7 and a plurality of slots 8 formed alternately in the circumferential direction, a coil 9 wound around the slots 8 and housed in the slots 8, and a sealing member (resin sealing portion 65) provided within the slots 8 to seal the coil 9, wherein a thermosetting resin composition is used to form the sealing member (resin sealing portion 65), The thermosetting resin composition is Epoxy resin and Hardener and It contains an inorganic filler, A thermosetting resin composition in which the particle size distribution of the inorganic filler has a D90 of 40 μm or more and 70 μm or less, and a D10 of 0.1 μm or more and 1.0 μm or less. <2> The ratio of D90 to D10 in the particle size distribution, D90 / D10, is 100 or more and 300 or less. <1> The thermosetting resin composition described in [reference]. <3> The ratio of D90 to D50 in the particle size distribution, D90 / D50, is 4 or more and 8 or less. <1> or <2> The thermosetting resin composition described in [reference]. <4> The amount of the inorganic filler is 90% by mass or more and 93% by mass or less of the total amount of the thermosetting resin composition. <1> ~ <3> A thermosetting resin composition according to any one of the following. <5> The inorganic filler comprises at least one selected from the group consisting of alumina, fused silica, and crystalline silica. <1> ~ <4> A thermosetting resin composition according to any one of the following. <6> The inorganic filler contains 60% by mass or more of alumina with respect to the entire thermosetting resin composition. <5> The thermosetting resin composition described in [reference]. <7> The gel time is between 40 seconds and 100 seconds. <1> ~ <6> A thermosetting resin composition according to any one of the following. <8> The thermal conductivity of the cured product of the thermosetting resin composition is 3.2 W / mK or higher. <1> ~ <7> A thermosetting resin composition according to any one of the following. <9> The epoxy resin comprises at least one selected from the group consisting of biphenyl-type epoxy resins, bisphenol-type epoxy resins, stilbene-type epoxy resins, novolac-type epoxy resins, polyfunctional epoxy resins, phenol aralkyl-type epoxy resins, and naphthol-type epoxy resins. <1> ~ <8> A thermosetting resin composition according to any one of the following. <10> The glass transition temperature is 175°C or higher. <1> ~ <9> A thermosetting resin composition according to any one of the following. <11> A stator 4 having a stator core 41 having a plurality of teeth 7 and a plurality of slots 8 formed alternately in the circumferential direction, a coil 9 wound around the slots 8 and housed in the slots 8, and a sealing member (resin sealing portion 65) provided within the slots 8 to seal the coil 9, The sealing member (resin sealing portion 65) <1> ~ <10> A stator comprising a cured product of the thermosetting resin composition described in any one of the above.

[0070] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted. [Examples]

[0071] The present invention will be described in detail below using examples, but the present invention is not limited in any way to the descriptions of these examples.

[0072] The raw material components used in each example and comparative example are shown below. (Epoxy resin) • Epoxy resin 1: Biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YL-6677) • Epoxy resin 2: Biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX-4000HK)

[0073] (Hardening agent) • Hardener 1: Novolac-type phenolic resin (manufactured by Sumitomo Bakelite Co., Ltd., PR-55617) • Hardener 2: Triphenolmethane-type phenolic resin (manufactured by Meiwa Chemicals Co., Ltd., MEH-7500)

[0074] (Inorganic filler) • Inorganic filler 1: Alumina 1 (molten spherical alumina (D50: 20 μm, circularity 0.92 or higher)) • Inorganic filler 2: Alumina 2 (molten spherical alumina (D50: 16.7 μm, circularity 0.92 or higher)) • Inorganic filler 3: Alumina 3 (fine alumina powder (D50: 0.7 μm)) • Inorganic filler 4: Silica 1 (molten spherical alumina (D50: 10.8 μm, circularity 0.92 or higher)) • Inorganic filler 4: Silica 2 (molten spherical alumina (D50: 0.5 μm, circularity 0.92 or higher))

[0075] (Curing accelerator) • Curing accelerator 1: Tetraphenylphosphonium 2,3-dihydroxynaphthalate • Curing accelerator 2: Tetraphenylphosphonium-4,4'-sulfonyl diphenolate

[0076] (Other additives) • Release agent: Carnauba wax (manufactured by Toa Chemical Co., Ltd., TOWAX-132) • Coupling agent: N-phenyl-3-aminopropyltrimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., CF-4083) • Low-stress material: Low-stress material (manufactured by Toray Dow Corning Co., Ltd., FZ-3730) • Coloring agent 1: Carbon black (manufactured by Mitsubishi Chemical Corporation, Carbon #5)

[0077] (Preparation of resin composition) First, the raw materials formulated according to Table 1 were mixed at room temperature using a mixer, and then roll-kneaded at a temperature between 70°C and 110°C. Next, the resulting mixture was cooled and then pulverized to obtain the resin composition.

[0078] The following measurements were performed on the resin compositions obtained in each example. The measurement results are shown in Table 1.

[0079] (Geltime) The gel time of the encapsulating resin compositions obtained in each example was measured. The gel time was measured by melting the encapsulating resin composition on a hot plate heated to 175°C and then measuring the time (gel time: seconds) until it hardened while being kneaded with a spatula.

[0080] (Glass transition temperature Tg) For each example, the glass transition temperature (Tg) of the cured resin composition was measured as follows. First, the sealing resin composition was injected using a transfer molding machine at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a curing time of 3 minutes to obtain a 15 mm × 4 mm × 4 mm test specimen. Next, the obtained test specimen was post-cured at 175°C for 4 hours, and then measured using a thermomechanical analyzer (TMA100, manufactured by Seiko Electronics Industries, Ltd.) under conditions of a measurement temperature range of 40°C to 300°C and a heating rate of 5°C / min. The glass transition temperature was calculated from these measurement results.

[0081] (Thermal conductivity) The resin compositions obtained in each example were injected and molded using a transfer molding machine at a mold temperature of 175°C, an injection pressure of 9.8 MPa, and a curing time of 3 minutes to obtain cured bodies measuring 10 mm × 10 mm × 1 mm. The thermal conductivity of the obtained cured material was calculated using the following formula, based on the thermal diffusivity (α) measured by the laser flash method (half-time method), the specific heat (Cp) measured by the DSC method, and the density (ρ) measured in accordance with JIS K 6911. The unit of thermal conductivity is W / m·K. Thermal conductivity [W / m K]=α[mm 2 / s] × Cp[J / kg·K] × ρ[g / cm 3 ]

[0082] (particle size distribution) The particle size distribution (D10, D50, D90) of the inorganic filler in each example was measured using a laser particle size analyzer (Shimadzu Corporation, SALD-7000). Based on the measurement results, the ratios D90 / 10 and D90 / D50 were calculated.

[0083] [Table 1]

[0084] This application claims priority based on Japanese Patent Application No. 2023-213558, filed on 19 December 2023, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0085] 1 case 2 rotors 4 stata 5 Permanent Magnets 6. York section 7 Teeth section 8 slots 9 coils 21 Coil housing section 41 Stator Core 50 resin layer 62, 72 Interior wall surface 65 Resin sealing part 100 motor

Claims

[Claim 1] A stator having a stator core having a plurality of teeth and a plurality of slots formed alternately in the circumferential direction, a coil wound around the slots and housed in the slots, and a sealing member provided in the slots to seal the coil, wherein a thermosetting resin composition is used to form the sealing member, The thermosetting resin composition is Epoxy resin and Hardener and It contains an inorganic filler, A thermosetting resin composition in which the particle size distribution of the inorganic filler has a D90 of 40 μm or more and 70 μm or less, and a D10 of 0.1 μm or more and 1.0 μm or less.

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