Stator, rotary electric machine and manufacturing method of stator

Abstract

To provide a technique for realizing a high heat conduction performance from a coil and a stator core while securing an insulation performance between the coil and the stator core.SOLUTION: In a stator 4 of a motor 100 comprising a coil 9 stored in a slot 8, an insulation sheet 50 disposed between a wall surface of the slot 8 and the coil 9 and a resin sealing part 30 which is provided while covering the coil 9 with a thermally curable resin composition, the insulation sheet 50 is provided in a mesh shape including a plurality of openings, and the thermally curable resin composition is provided while being immersed in the openings of the insulation sheet 50. In the stator 4, an electric insulation property of the insulation sheet 50 has an insulation breakage strength of 20 kV / mm or more, and an opening ratio of a surface with the openings of the insulation sheet 50 is from 25% or more to 70% or less.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a stator, a rotating electric machine, and a method for manufacturing a stator. [Background technology]

[0002] In rotating electric machines such as motors, in order to ensure insulation, when insulating material is placed between components to be insulated, such as the gap between a stator core (slot inner wall) and a coil, a known technique is to insert insulating paper into the gap between the slot inner wall and the coil and treat the coil with insulating varnish.

[0003] For example, a technology has been proposed for an insulating sheet capable of filling the gap between components to be insulated and insulating and bonding them together (see, for example, Patent Document 1). Specifically, this document discloses an insulating sheet having a substrate made of one or more of insulating paper, insulating film, nonwoven fabric, and mesh cloth, and an insulating resin layer made of an uncured or semi-cured thermosetting resin composition formed on one or both sides of the substrate, the thermosetting resin composition being a thermosetting resin (A) that is solid at 25°C, a thermosetting resin (B) that is liquid at 25°C, and a latent curing agent that is inactive at 60°C or less, the thermosetting resin (A) being in the range of 10 to 90 parts by mass relative to a total of 100 parts by mass of the thermosetting resin (A) and the thermosetting resin (B), and the insulating resin layer being formed in an area other than either one or both of an area to be cut and an area to be processed by bending and forming. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2022-185658 A Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, there has been a demand for smaller motors with higher output, and this has led to a demand for improved coil packing rates in the slots. As a result, the insulating coating film on the coils has become thinner, making the coil conductor more likely to be exposed due to scratches. Although placing an insulating sheet between the inner wall of the slot and the coil as described above reduces such concerns, there is a risk that the heat transfer performance from the coil to the stator core will decrease.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide a technique for realizing high heat transfer performance from the coil to the stator core while ensuring insulation performance between the coil and the stator core. [Means for solving the problem]

[0007] According to the present invention, the following techniques are provided. (1) A stator for a rotating electric machine comprising: a coil accommodated in a slot; an insulating sheet disposed between a wall surface of the slot and the coil; and a sealing member provided by covering the coil with a thermosetting resin composition, The insulating sheet is provided in a mesh shape having a plurality of openings, the thermosetting resin composition is provided so as to infiltrate into the openings of the insulating sheet, The electrical insulation of the insulating sheet has a dielectric breakdown strength of 20 kV / mm or more, A stator, wherein an opening ratio of a surface of the insulating sheet due to the openings is 25% or more and 70% or less. (2) The stator according to (1), wherein the insulating sheet has a heat resistance temperature of 100°C or higher. (3) The slot according to (1) or (2), wherein the insulating sheet has a thickness of 100 μm or more and 500 μm or less. (4) the thermosetting resin composition covers at least one end of the coil protruding from the slot; the insulating sheet is provided so as to protrude in an axial direction from the slot in a portion of the coil that is covered with the thermosetting resin composition, The stator according to any one of (1) to (3), wherein the protrusion amount of the insulating sheet is 0.1 mm or more and 10 mm or less. (5) The stator according to any one of (1) to (4), wherein the insulating sheet is a single-layer sheet selected from the group consisting of insulating paper, insulating film, nonwoven fabric, and mesh cloth, or a sheet formed by laminating a plurality of layers selected from the group, and having openings (mesh openings). (6) The stator according to any one of (1) to (5), wherein the minimum width of the opening is 0.05 mm or more and 3 mm or less. (7) The thermosetting resin composition comprises: Epoxy resin, A hardener; and an inorganic filler, The stator according to any one of (1) to (6), wherein the maximum diameter of the inorganic filler is 0.5 mm or less. (8) The stator according to any one of (1) to (7), wherein the glass transition temperature Tg of the thermosetting resin composition is 140° C. or higher. (9) A rotating electric machine having a stator according to any one of (1) to (8). (10) A method for manufacturing a stator according to any one of (1) to (8), an insulating sheet arrangement step of arranging a mesh-shaped insulating sheet along a wall surface inside the slot; a coil housing step of housing a coil in the slot in which the insulating sheet is disposed; a resin filling step of filling the slot with a thermosetting resin composition to seal the coil with the thermosetting resin composition and to allow the thermosetting resin composition to penetrate into the opening of the insulating sheet; A method for manufacturing a stator comprising the steps of: Effect of the Invention

[0008] According to the present invention, a technique is provided that realizes high heat transfer performance from the coil to the stator core while ensuring insulation performance between the coil and the stator core. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a motor according to an embodiment taken along a direction perpendicular to a rotation axis of the motor; [Diagram 2] 1 is a vertical cross-sectional view of a motor according to an embodiment taken along a rotation axis thereof; [Diagram 3] FIG. 4 is an enlarged view of the periphery of a slot according to the embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. 3 according to the embodiment. [Diagram 5] 4 is a cross-sectional view taken along line AA of FIG. 3 of a modified example of the embodiment. [Figure 6] 5A to 5C are diagrams illustrating a stator manufacturing process according to the embodiment. [Figure 7] 5A to 5C are diagrams illustrating a stator manufacturing process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In this embodiment, a motor 100 is exemplified as a rotating electric machine. Fig. 1 is a schematic cross-sectional view perpendicular to the rotational axis direction of motor 100. Fig. 2 is a schematic cross-sectional view of motor 100 in the rotational axis direction. Fig. 3 is an enlarged view of the periphery of the slot (area X in Fig. 1), and is a schematic cross-sectional view of the portion where coil 9 protrudes from the end of slot 8. Fig. 4 is a cross-sectional view taken along line AA in Fig. 3.

[0011] <Basic structure of motor 100> The motor 100 includes a case 1, and a rotor 2, a stator 4, and a coil 9 housed inside the case 1.

[0012] <Case 1> The case 1 is configured to have a cylindrical portion 1a and side plate portions 1b, 1c that close both axial ends of the cylindrical portion 1a. The case 1 can be made of a material such as an aluminum alloy (cast metal casting), a resin material, or a combination thereof.

[0013] <Rotor 2> As shown in Fig. 1, the rotor 2 is housed inside the case 1. At the center of the rotor 2, a rotating shaft 3 is attached as an output shaft, as shown in Fig. 2. Both ends of the rotating shaft 3 are supported by the side plate portions 1b, 1c via bearings 3a. This allows the rotor 2 to freely rotate around the rotating shaft 3.

[0014] Permanent magnets 5 are installed inside the rotor 2. Specifically, as shown in Fig. 1, a plurality of (eight here) 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 different from each other.

[0015] <Stator 4> 2, a cylindrical stator 4 is disposed and fixed on the inner peripheral side of the cylindrical portion 1a so as to surround the outer periphery of the rotor 2. A minute gap (air gap) is provided between the inner peripheral surface of the stator 4 and the outer peripheral surface of the rotor 2. The stator 4 has a stator core 41 and coils 9.

[0016] <Stator core 41> Stator core 41 is provided by stacking multiple electromagnetic steel plates in the axial direction and closely fixing them together, and when viewed from the axial end as shown in Fig. 1, it is provided with a yoke portion 6 provided in an annular shape and multiple teeth portions 7 extending from yoke portion 6 toward rotor 2 (inner circumference side). The multiple teeth portions 7 are provided and arranged at equal intervals in the circumferential direction. Here, 24 teeth portions 7 are provided as shown in Fig. 1. Slots 8 are provided between each of the teeth portions 7.

[0017] <Coil 9> The coil 9 is a rectangular wire in a U-shape, and is wound so as to straddle the teeth 7 and be housed in two spaced apart slots 8. Here, it is housed in a sealed state in a resin sealing portion 65 that seals the slot 8 (see FIG. 3, for example). The coil 9 is completed by welding the ends (coil ends) of the segment-shaped coil.

[0018] The coil 9 has a coil body 91, a first coil end 92, and a second coil end 93. The coil body 91 refers to the portion housed in the slot 8. The first coil end 92 refers to the portion protruding to one axial side of the stator core 41 (upper side in FIG. 4). The second coil end 93 refers to the portion protruding to the other axial side of the stator core 41 (lower side in FIG. 4). As will be described later, an insulating sheet 50 is provided between the coil 9 and the stator core 41, and the coil 9 is covered and sealed by a resin sealing portion 65.

[0019] <Teeth part 7> The teeth 7 are provided to correspond to the permanent magnets 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to attraction and repulsion between the corresponding permanent magnets 5.

[0020] The teeth 7 are tapered so that the circumferential width is large on the outer periphery and small on the inner periphery. Teeth tips 71 are formed at the inner periphery end of the teeth 7, facing each other in the circumferential direction so as to reduce the width of the slot 8.

[0021] <Slot 8> The slots 8 are spaces between adjacent teeth 7, and are provided such that wall surfaces 72 of the teeth 7 facing each other in the radial direction are parallel to each other, as shown in Fig. 3. The space between the tips 71 of the teeth forms an opening on the inner circumferential side of the slots 8.

[0022] As shown in FIG. 3, the slot 8 has a plurality of coils 9 arranged radially when viewed from above, an insulating sheet 50 provided between the coils 9 and the inner wall of the slot 8 (the tooth portion wall surface 72 and the yoke portion wall surface 62), and a resin sealing portion 65 filled in the space excluding the coils 9 and the insulating sheet 50.

[0023] <Insulating sheet 50> Insulating sheet 50 is provided in slot 8 between coil 9 and stator core 41, so as to be "U-shaped" when viewed from above (as viewed from the axial end side) as shown in Fig. 3, so as to follow yoke wall surface 62 and teeth wall surface 72. Also, as shown in Fig. 4, insulating sheet 50 has sheet accommodating portion 51 accommodated in slot 8, and sheet protruding portion 52 protruding a predetermined length (protruding amount t1) from the upper and lower ends of slot 8 (teeth upper surface 75a and teeth lower surface 75b in Fig. 4).

[0024] The length of the sheet protrusion 52 in the up-down direction (protrusion amount t1) is, for example, 0.1 to 10 mm. By setting the protrusion amount t1 of the sheet protrusion 52 of the insulating sheet 50 within the above range, it is possible to reliably prevent the coil 9 from coming into contact with the opening edge of the stator core 41 when the coil 9 is accommodated in the slot 8. Furthermore, even if the coil 9 comes into contact with the insulating sheet 50, it is possible to prevent the sheet protrusion 52 of the insulating sheet 50 from entering the slot 8 entirely.

[0025] The insulating sheet 50 is a single-layer sheet selected from the group consisting of insulating paper, insulating film, nonwoven fabric, and mesh cloth, or a sheet formed by laminating multiple layers selected from this group, and has multiple openings (mesh openings).

[0026] The thickness of the insulating sheet 50 is 100 μm or more and 500 μm or less. The lower limit of the thickness is preferably 150 μm or more, and more preferably 200 μm or more. By setting the lower limit of the thickness within the above range, the shape when accommodated in the slot 8 can be properly maintained. In other words, the insulating sheet 50 can stand on its own in the "U-shape" as viewed from above. The upper limit of the thickness is preferably 400 μm or less, and more preferably 350 μm or less. By setting the upper limit of the thickness within the above range, the occupancy rate of the coil 9 in the slot 8 can be increased.

[0027] The opening shape (shape of the openings) is not particularly limited, but it is preferable that the opening shape is not easily deformed and does not catch the coil 9 when inserting the coil 9. The opening shape may be the same over the entire insulating sheet 50, or may differ depending on the location.

[0028] The resin sealing portion 65 penetrates into the opening of the insulating sheet 50. That is, when the thermosetting resin composition, which is the material for the resin sealing portion 65, is filled in the slot 8 to provide the resin sealing portion 65, the thermosetting resin composition penetrates into the opening of the insulating sheet 50 and hardens. Since the resin sealing portion 65 is filled so as to prevent the insulating sheet 50 from opening, the coil 9 side of the insulating sheet 50 and the wall surface side of the slot 8 (the tooth portion wall surface 72 side and the yoke portion wall surface 62 side) are directly connected by the resin sealing portion 65. As a result, the heat transfer performance is not reduced by the insulating sheet 50, and the heat of the coil 9 can be transferred to the stator core 41 by the resin sealing portion 65, which is the same component. In addition, since the insulating sheet 50 and the resin sealing portion 65 are integrated, it is possible to suppress the occurrence of a gap between the insulating sheet 50 and the resin sealing portion 65 due to aging caused by the use of the motor 100. That is, it is possible to prevent the occurrence of a gap and the decrease in heat transfer efficiency.

[0029] The aperture ratio of the insulating sheet 50 can be 20% or more and 70% or less. The lower limit of the aperture ratio is preferably 25% or more, and more preferably 30% or more. By setting the lower limit of the aperture ratio in the above range, the resin sealing portion 65 can be sufficiently filled into the openings of the insulating sheet 50. The upper limit of the aperture ratio is preferably 65% ​​or less, and more preferably 60% or less. By setting the upper limit of the aperture ratio within the above range, it is possible to properly maintain the shape of the insulating sheet 50 when it is housed in the slot 8 in order to seal the coil 9 with the resin sealing portion 65.

[0030] The minimum width of the opening (mesh) of the insulating sheet 50 is 0.05 mm or more and 3 mm or less. The lower limit of the minimum width of the opening (mesh) is preferably 0.1 mm or more, more preferably 0.3 mm or more. The upper limit of the minimum width of the opening is preferably 2.5 mm or less, more preferably 2.0 mm or less. By setting the lower limit of the minimum width of the opening within the above range, the resin sealing part 65 (i.e., the thermosetting resin composition) can be appropriately filled into the opening. In particular, it is set according to the particle size (maximum diameter, average particle size, particle size distribution) of the inorganic filler (filler) in the thermosetting resin composition. The upper limit of the minimum width of the opening is set from the viewpoint of the shape maintenance and self-supporting property when placed in the slot 8, together with the particle size of the inorganic filler (filler) in the thermosetting resin composition. That is, if the minimum width of the opening is too large, there is a risk that the shape of the insulating sheet 50 becomes unstable, so an upper limit is set so that the shape does not become unstable.

[0031] The electrical insulation of the insulating sheet 50 has a dielectric breakdown strength of 20 kV / mm or more. The dielectric breakdown strength is preferably 30 kV / mm or more, and more preferably 40 kV / mm or more. The dielectric breakdown strength is measured by a dielectric breakdown test method specified in JIS C 2300. The dielectric breakdown strength depends on the output of the motor 100, i.e., the magnitude of the power (current and voltage) flowing through the coil 9. For example, when considering use in electric vehicles, which have been developed in recent years and have become higher in output, if the dielectric breakdown strength is less than 20 kV / mm, the dielectric breakdown property is poor and it is difficult to use it as electrical insulating paper.

[0032] The heat resistance temperature of the insulating sheet 50 is 100°C or higher. Since the temperature of the stator 4 rises due to heat generation by the coil 9, the heat resistance temperature is 100°C or higher, preferably 150°C or higher, and more preferably 200°C or higher, taking into consideration the upper temperature limit of the stator 4. The heat resistance temperature index, which is an index of durability and heat resistance, is calculated according to a procedure in accordance with JEC-6151 "General Rules for Heat Resistance Test Methods for Electrical Insulating Materials" (Standard of the Electrical Standards Research Committee of the Institute of Electrical Engineers of Japan), by determining the temperature and time at which the tensile strength is reduced by half from the initial value of the tensile strength, and then calculating the temperature index after 20,000 hours.

[0033] As the insulating sheet 50, for example, the following products can be used. Product (1): Multi-layer laminate material (Nitto Shinko, NPN-222) Product (2): Aramid fiber (DuPont Teijin Advanced Paper, Nomex, Type 410) Product (3): PTFE mesh (Flon Industries, F3261-05, equivalent to 18 mesh) Product (4): Cell strainer (Funakoshi, Mini Cell Strainer II, nylon mesh 70 μm) Product (5): Polypropylene mesh (Daio Kasei, Crown Net 24 Mesh) Product (6): Polyester mesh (manufactured by Nippon Tokushu Orimono Co., Ltd., TNo. 60SS). Product (7): Polyester mesh fabric (Super Strong 200 mesh, manufactured by Nihon Tokushu Orimono Co., Ltd.) Product (8): Polyethylene terephthalate mesh sheet (NBC Meshtec, TB30) Product (9): Polyethylene terephthalate mesh sheet (PET mesh) (manufactured by Taiki Shoji Co., Ltd., product name "OKILON HYBRID") Product (10): PTFE mesh (Flon Industries, F3261-05, equivalent to 18 mesh) Product (11): 100 mesh polyethylene mesh filter (manufactured by AS ONE Corporation, product name: "Polyethylene Mesh") Product (12): Nylon mesh (manufactured by Taiki Shoji Co., Ltd., product name "OKILON-Sha 2520") Product (13): Woven fabric (warp / weft: polyethylene terephthalate monofilament) (NBC Meshtec Co., Ltd., L-screen165-027 / 420PW) Product (14): Mesh silver black (Daio Kasei's "Silver Black Magic Net" (20 mesh, polyester)) Product (15): Mesh gray white (manufactured by Daio Kasei, "PP Gray" (24 mesh, made of polypropylene))

[0034] <Resin sealing part 65> 3, the resin sealing portion 65 is provided on the inner periphery side of the slot 8 (the tooth tip 71 side). The resin sealing portion 65 is provided by insert molding. The resin material used for the resin sealing portion 65 is a thermosetting resin (sealing resin composition) described next.

[0035] In this embodiment, the resin sealing portion 65 seals the coil 9 (i.e., the coil body 91) in the slot 8. As described above, the resin sealing portion 65 penetrates into the opening of the insulating sheet 50 arranged between the wall surface of the slot 8 (the tooth portion wall surface 72, the yoke portion wall surface 62) and the coil 9, and hardens.

[0036] In the example shown in Fig. 4, the resin sealing portion 65 is filled only inside the slot 8. That is, it seals the coil body 91 of the coil 9 and the sheet accommodating portion 51 of the insulating sheet 50. However, without being limited to this, as shown in Fig. 5, the coil end 92 of the coil 9 protruding from the slot 8 and the sheet protruding portion 52 of the insulating sheet 50 may also be sealed. In this case, only one of the upper and lower coil ends 92 and the sheet protruding portion 52 may be sealed.

[0037] (Thermosetting resin composition)

[0038] Hereinafter, the components used in the thermosetting resin composition of the present embodiment (sometimes referred to simply as "resin composition" in this specification) will be described.

[0039] (Epoxy resin) Examples of the epoxy resin used in the thermosetting resin composition of the present embodiment include bifunctional or crystalline epoxy resins such as biphenyl type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, stilbene type epoxy resins, and hydroquinone type epoxy resins; novolac type epoxy resins such as cresol novolac type epoxy resins, phenol novolac type epoxy resins, and naphthol novolac type epoxy resins; phenol aralkyl type epoxy resins such as phenylene skeleton-containing phenol aralkyl type epoxy resins, biphenylene skeleton-containing phenol aralkyl type epoxy resins, and phenylene skeleton-containing naphthol aralkyl type epoxy resins; trifunctional type epoxy resins such as triphenol methane type epoxy resins and alkyl-modified triphenol methane type epoxy resins; modified phenol type epoxy resins such as dicyclopentadiene-modified phenol type epoxy resins and terpene-modified phenol type epoxy resins; heterocyclic type epoxy resins such as triazine nucleus-containing epoxy resins, etc. These may be used alone or in combination of two or more. From the viewpoints of ensuring the fluidity of the resulting resin composition and the strength of a cured product of the resin composition, the epoxy resin preferably contains one or more epoxy resins selected from the group consisting of phenol novolac type epoxy resins and phenol aralkyl type epoxy resins, and more preferably contains a cresol novolac type epoxy resin.

[0040] The content of the epoxy resin in the resin composition may be, for example, 3 mass% or more, preferably 8 mass% or more, more preferably 10 mass% or more, and even more preferably 12 mass% or more, based on the total solid content of the resin composition, from the viewpoint of improving the fluidity of the obtained resin composition and improving the workability and moldability. In addition, from the viewpoint of improving the strength and heat resistance of a cured product formed using the resin composition, the content of the epoxy resin is preferably 30 mass % or less, and more preferably 20 mass % or less, based on the total solid content of the resin composition.

[0041] In this embodiment, the total solid content of the resin composition refers to the non-volatile content in the resin composition, and refers to the remainder excluding volatile components such as water, solvent, etc. In addition, in this embodiment, the content relative to the total amount of the resin composition refers to the content relative to the total solid content of the resin composition excluding the solvent, when a solvent is included.

[0042] In one embodiment, the resin composition may further contain a thermosetting resin other than the epoxy resin. Examples of the thermosetting resin that can be used include bismaleimide resin, benzoxazine resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, polyurethane resin, diallyl phthalate resin, silicone resin, cyanate resin, polyimide resin, polyamideimide resin, and benzocyclobutene resin. These thermosetting resins may be used alone or in combination of two or more.

[0043] (hardening agent) The curing agent used in the thermosetting resin composition of the present embodiment is not limited as long as it is generally used in resin compositions containing epoxy resins, and examples thereof include phenolic resin-based curing agents, amine-based curing agents, acid anhydride-based curing agents, mercaptan-based curing agents, and other curing agents. Among these, phenolic resin-based curing agents are preferred in terms of the balance of flame resistance, moisture resistance, electrical properties, curability, storage stability, and the like.

[0044] The phenolic resin-based curing agent may be, for example, any one generally used in epoxy resin compositions. More specifically, the phenolic resin-based curing agent may be a novolac resin obtained by condensing or co-condensing phenols such as phenol novolac resin, cresol novolac resin, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, α-naphthol, β-naphthol, dihydroxynaphthalene, and the like with formaldehyde or ketones under an acid catalyst; a phenol aralkyl resin having a phenylene skeleton synthesized from the above-mentioned phenols and dimethoxyparaxylene or bis(methoxymethyl)biphenyl; a phenol aralkyl resin such as a phenol aralkyl resin having a biphenylene skeleton; and a phenolic resin having a trisphenylmethane skeleton. These may be used alone or in combination of two or more. The phenolic resin-based curing agent preferably includes a phenol novolac resin.

[0045] When the curing agent is a phenolic resin-based curing agent, the equivalent ratio between the epoxy resin and the curing agent, i.e., the ratio of (the number of moles of epoxy groups in the epoxy resin / the number of moles of phenolic hydroxyl groups in the phenolic resin-based curing agent) is preferably 0.5 or more, more preferably 0.6 or more, and even more preferably 0.8 or more, from the viewpoint of improving the moldability and reliability of the resin composition. Also, from the same viewpoint, the above ratio is preferably 2 or less, more preferably 1.8 or less, and even more preferably 1.5 or less.

[0046] Examples of amine-based curing agents include aliphatic polyamines such as diethylenetriamine (DETA), triethylenetetramine (TETA), and metaxylylenediamine (MXDA); aromatic polyamines such as diaminodiphenylmethane (DDM), m-phenylenediamine (MPDA), and diaminodiphenylsulfone (DDS); and polyamine compounds such as dicyandiamide (DICY) and organic acid dihydralazide. These may be used alone or in combination of two or more.

[0047] Examples of the acid anhydride curing agent include alicyclic acid anhydrides such as hexahydrophthalic anhydride (HHPA), methyltetrahydrophthalic anhydride (MTHPA), and maleic anhydride; and aromatic acid anhydrides such as trimellitic anhydride (TMA), pyromellitic anhydride (PMDA), benzophenonetetracarboxylic acid (BTDA), and phthalic anhydride. These may be used alone or in combination of two or more.

[0048] Examples of mercaptan-based curing agents include trimethylolpropane tris(3-mercaptobutyrate) and trimethylolethane tris(3-mercaptobutyrate). These may be used alone or in combination of two or more.

[0049] Examples of other curing agents include isocyanate compounds such as isocyanate prepolymers and blocked isocyanates; and organic acids such as carboxylic acid-containing polyester resins. The curing agent may be a combination of two or more different types of curing agents from the above.

[0050] From the viewpoint of realizing excellent fluidity and improving filling properties and moldability in the encapsulation process, the content of the curing agent in the resin composition is preferably 0.5 mass % or more, more preferably 1 mass % or more, and even more preferably 3 mass % or more, based on the total amount of the resin composition. On the other hand, from the viewpoint of improving the moisture resistance reliability and heat resistance of the cured resin product, the content of the curing agent is preferably 20 mass % or less, more preferably 15 mass % or less, even more preferably 10 mass % or less, and even more preferably 5 mass % or less, based on the total amount of the resin composition.

[0051] (Inorganic filler) Examples of inorganic fillers include fused silica such as fused crushed silica and fused spherical silica, silica such as crystalline silica, alumina, aluminum hydroxide, silicon nitride, and aluminum nitride. These may be used alone or in combination of two or more. From the viewpoint of making the mechanical properties or thermal properties of the cured product of the resin composition favorable, the inorganic filler preferably contains silica, and more preferably contains one or more selected from the group consisting of crushed silica and fused spherical silica.

[0052] From the viewpoint of favorable filling of the openings (slits) of the insulating sheet 50, the maximum diameter of the inorganic filler can be 0.5 mm or less, preferably 0.1 mm or less, and more preferably 0.05 mm or less. However, the maximum diameter of the inorganic filler is preferably smaller than the minimum width of the openings of the insulating sheet 50, and is preferably, for example, 50% or less of the minimum width. By setting the maximum diameter of the inorganic filler in such a range, when the resin sealing portion 65 is provided in the slot 8, the openings of the insulating sheet 50 are not blocked by the inorganic filler, and the resin composition can be appropriately filled.

[0053] The average particle size d50 of the inorganic filler is preferably 0.01 μm or more, more preferably 1 μm or more, and even more preferably 5 μm or more, from the viewpoint of improving the fluidity of the resin composition and improving moldability. Also, the average particle size d50 of the inorganic filler is preferably 50 μm or less, more preferably 40 μm or less, from the viewpoint of improving the filling property and suppressing the occurrence of unfilled portions.

[0054] In addition, two or more fillers having different average particle diameters d50 may be used in combination as the inorganic filler. This makes it possible to more effectively increase the filling ability of the inorganic filler relative to the total solid content of the resin composition. For example, from the viewpoint of improving the filling ability of the resin composition, the inorganic filler preferably includes a first filler having an average particle diameter of 1 μm or more and 12 μm or less, and a second filler having an average particle diameter of more than 12 μm and 30 μm or less. From the same viewpoint, the inorganic filler may include, for example, a first filler having an average particle diameter of 0.01 μm or more and 1 μm or less, and a second filler having an average particle diameter of more than 1 μm and 50 μm or less.

[0055] In addition, the value of (d50 / d90) calculated from the particle diameter d90 of the inorganic filler with a cumulative frequency of 90% measured using a laser diffraction particle size distribution analyzer and the average particle diameter d50 of the inorganic filler is preferably 0.2 or more, more preferably 0.25 or more, and even more preferably 0.3 or more, from the viewpoint of improving the fluidity of the resin composition. In addition, in order to improve the narrow-part filling property, the above ratio (d50 / d90) is preferably 1.0 or less, more preferably 0.9 or less, and even more preferably 0.8 or less.

[0056] Here, the particle size of the inorganic filler, specifically d50, d90 and maximum diameter, can be obtained by measuring the particle size distribution of the particles on a volume basis using a commercially available laser diffraction particle size distribution measuring device (e.g., SALD-7000, manufactured by Shimadzu Corporation).

[0057] The content of the inorganic filler in the resin composition is preferably 50% by mass or more, more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more, based on the total amount of the resin composition, from the viewpoint of suppressing the moisture absorption and thermal expansion of the resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. In addition, from the viewpoint of more effectively improving the flowability and filling property during molding of the resin composition, the content of the inorganic filler is preferably 95% by mass or less, more preferably 93% by mass or less, based on the total amount of the resin composition.

[0058] In addition, when the inorganic filler contains silica, the content of silica in the resin composition is preferably 50 mass % or more, more preferably 65 mass % or more, and even more preferably 80 mass % or more, based on the total amount of the resin composition, from the viewpoint of suppressing the moisture absorption and thermal expansion of the resin composition and more effectively improving the temperature cycle resistance and moisture resistance of the cured product of the resin composition. From the viewpoint of more effectively improving the fluidity and filling property of the resin composition during molding, the content of silica in the resin composition is preferably 95% by mass or less, and more preferably 93% by mass or less.

[0059] (Other Ingredients) In the present embodiment, the resin composition may further include components other than the above-mentioned components. For example, the resin composition may further include a curing accelerator, a coupling agent, a flame retardant, an ion scavenger, a colorant, and an antioxidant.

[0060] (Cure accelerator) The curing accelerator may be any accelerator that accelerates the crosslinking reaction between the epoxy resin and the curing agent, and any accelerator that is generally used in epoxy resin compositions may be used. Specific examples of curing accelerators include diazabicycloalkenes and derivatives thereof such as 1,8-diazabicyclo(5,4,0)undecene-7; organic phosphines such as triphenylphosphine and methyldiphenylphosphine; imidazole compounds (imidazole curing accelerators) such as 2-methylimidazole; and tetra-substituted phosphonium and tetra-substituted borates such as tetraphenylphosphonium and tetraphenylborate.

[0061] Examples of the imidazole-based curing accelerator include imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenyl Examples of such compounds include imidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecylimidazolyl(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2,4-diamino-6-[2'-methylimidazolyl(1')]-ethyl-s-triazine, an isocyanuric acid adduct of 2-phenylimidazole, an isocyanuric acid adduct of 2-methylimidazole, 2-phenyl-4,5-dihydroxydimethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0062] (Coupling Agent) As the coupling agent, for example, various silane-based compounds such as epoxysilane, mercaptosilane, aminosilane, alkylsilane, ureidosilane, vinylsilane, methacrylsilane, titanium-based compounds, aluminum chelates, aluminum / zirconium-based compounds, and other known coupling agents can be used. Examples of these include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, γ-methacryloxypropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, vinyltriacetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, γ-anilinopropylmethyldimethoxysilane, γ-[bis(β-hydroxyethyl)]aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyl N-(vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropyltriethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropylmethyldimethoxysilane, phenylaminopropyltrimethoxysilane, γ-(β-aminoethyl)aminopropyldimethoxymethylsilane, N-(trimethoxysilylpropyl)ethylenediamine, N-(dimethoxymethylsilylisopropyl)ethylenediamine, methyltrimethoxysilane, dimethyldimethoxysilane, methyltriethoxysilane, N-(vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilane, vinyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-triethoxysilyl-N-(1,Silane coupling agents such as hydrolyzate of 3-dimethyl-butylidene)propylamine, isopropyl triisostearoyl titanate, isopropyl tris(dioctyl pyrophosphate) titanate, isopropyl tri(N-aminoethyl-aminoethyl) titanate, tetraoctyl bis(ditridecyl phosphite) titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate Examples of titanate-based coupling agents include ethylene titanate, bis(dioctyl pyrophosphate) titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumyl phenyl titanate, and tetraisopropyl bis(dioctyl phosphite) titanate. These may be used alone or in combination of two or more. Among these, silane-based compounds such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, or vinyl silane are more preferred. In addition, from the viewpoint of more effectively improving filling properties and moldability, it is even more preferred to use secondary amino silanes such as phenyl aminopropyl trimethoxy silane.

[0063] When a coupling agent is used, the content is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total solid content of the resin composition, from the viewpoint of making the flowability of the resin composition favorable. Also, from the viewpoint of improving the mechanical strength of the cured product of the resin composition, the content of the coupling agent is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total solid content of the resin composition.

[0064] (Coloring agent) Examples of the colorant include carbon black, red iron oxide, titanium oxide, etc. Among them, carbon black is preferably used as the colorant. The content of the colorant is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the total amount of the resin composition, from the viewpoint of obtaining a preferable appearance of the cured product of the resin composition. Also, from the viewpoint of obtaining a preferable resin viscosity, the content of the colorant is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and even more preferably 0.5% by mass or less, based on the total amount of the resin composition.

[0065] (Antioxidants) Examples of the antioxidant include hindered phenol compounds, hindered amine compounds, and thioether compounds.

[0066] (Characteristics of the thermosetting resin composition or its cured product) Next, the properties of the thermosetting resin composition of this embodiment or the cured product thereof will be described.

[0067] The resin composition of the present embodiment has a thermal conductivity of, for example, 0.7 W / mK or more, preferably 2 W / mK or more, and more preferably 3 W / mK or more after curing. By setting the thermal conductivity within such a range, heat from the coil 9 can be effectively transferred to the stator core 41.

[0068] The glass transition temperature Tg of the cured product of the resin composition is, for example, 140° C. or higher, preferably 150° C. or higher, and more preferably 160° C. or higher. By setting the glass transition temperature Tg within the above range, the motor 100 becomes resistant to heat generation and can accommodate higher output.

[0069] (Method for producing thermosetting resin composition) The resin composition of the present embodiment can be produced by uniformly mixing the above components and additives used as necessary in a mixer or blender such as a tumbler mixer or a Henschel mixer to a predetermined content, and then kneading while heating with a kneader, roll, disperser, azihomobister, planetary mixer, etc. The temperature during kneading must be in a temperature range in which a curing reaction does not occur, and although it depends on the composition of the epoxy resin and the curing agent, it is preferable to melt-knead at about 70 to 150 ° C. After kneading, it may be cooled and solidified, and the kneaded product may be processed into a powder, granule, tablet, or sheet.

[0070] A method for obtaining a powdered resin composition includes, for example, a method of crushing the kneaded material with a crushing device. The kneaded material may be formed into a sheet and crushed. Examples of the crushing device that can be used include a hammer mill, a stone mill, and a roll crusher.

[0071] As a method for obtaining a granular or powdery resin composition, for example, a granulation method represented by a hot-cut method can be used in which a die having a small diameter is provided 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, etc. In this case, after obtaining a granular or powdery resin composition by a granulation method such as the hot-cut method, it is preferable to perform degassing before the temperature of the resin composition drops too much.

[0072] <Manufacturing method of stator 4> A manufacturing method of the stator 4 of this embodiment will be described with reference to Fig. 6 and Fig. 7. Fig. 6 shows the manufacturing process in a top view (corresponding to Fig. 3). Fig. 7 shows the manufacturing process in a cross-sectional view (corresponding to Fig. 4).

[0073] (Insulating sheet placement process) A stator core 41 is prepared by laminating a plurality of electromagnetic steel sheets in the axial direction and fixing them in close contact with each other, and is placed in a mold. At this time, one end face (here, the lower end face) of the stator core 41 in the axial direction is attached to a lower mold. The upper mold is not fitted to the other end face (i.e., the upper end face), and the upper side of the slot 8 is open. Then, as shown in FIG. 6(a) and FIG. 7(a), a mesh-shaped insulating sheet 50 is accommodated in the slot 8. At this time, the insulating sheet 50 is folded in a substantially U-shape along the tooth portion wall surface 72 and the yoke portion wall surface 62 in the slot 8 and placed therein. At this time, both ends (sheet protruding portion 52) of the insulating sheet 50 protrude from the end of the stator core 41 by a predetermined length t1. Note that a jig for guiding the insertion may be used to smoothly insert the insulating sheet 50 into the slot 8 and place it in a predetermined position close to the wall surface.

[0074] (Coil accommodation process) Next, after placing insulating sheets 50 in all of the slots 8, the coils 9 are placed in the slots 8 as shown in Fig. 6(b) and Fig. 7(b). As a result, the insulating sheets 50 are placed between the wall surfaces of the slots 8 and the coils 9.

[0075] (Resin filling process) After all the coils 9 are placed in the slots 8, a resin composition is filled into the slots 8 and insert-molded to obtain a resin-sealed portion 65 in which the coils 9 are resin-sealed within the slots 8. At this time, the thermosetting resin composition permeates into the openings of the insulating sheet 50, and a part of the resin-sealed portion 65 is formed in the region of the opening of the insulating sheet 50. As a result, the resin-sealed portion 65 is not divided by the insulating sheet 50, and is connected between the coil 9 side of the insulating sheet 50 and the wall side of the slot 8 (the tooth portion wall surface 72 side and the yoke portion wall surface 62 side).

[0076] As described above, according to this embodiment, by providing insulating sheet 50 between the wall surfaces (yoke wall surface 62, teeth wall surface 72) of slot 8 and coil 9, it is possible to ensure insulation between stator core 41 and coil 9. By making the electrical insulation of insulating sheet 50 have a dielectric breakdown strength of 20 kV / mm or more, it is possible to accommodate higher output of motor 100. Since insulating sheet 50 has mesh-like openings, resin sealing portion 65 is filled into the openings, which makes it possible to suppress a decrease in heat transfer efficiency caused by insulating sheet 50. In particular, since the opening ratio of the surface of insulating sheet 50 due to the openings is 25% or more and 70% or less, a sufficient amount of resin sealing portion 65 can be filled into the openings, and a sufficient heat transfer path passing through resin sealing portion 65 filled into the openings of insulating sheet 50 can be ensured. EXAMPLES

[0077] The present invention will be described in detail below using examples, but the present invention is not limited to the description of these examples. Here, the "self-supporting property" and "insulating property" were evaluated.

[0078] <Independence assessment test> Regarding independence, the mesh sheet was inserted into the inner wall of the stator slot from the top of the teeth, and when the mesh sheet was brought into contact with the lower die at the bottom of the teeth in order to make the mesh sheet stand on its own, if the mesh sheet bent inside the slot, it was rated as NG, and if the mesh sheet did not bend inside the slot, it was rated as OK. As the mesh sheet, the products (1) to (15) given as examples of the insulating sheet 50 were used. The height of the slot was 200 mm, the length of the teeth of the slot was 30 mm, and the width of the yoke side wall surface of the slot was 15 mm.

[0079] <Insulation evaluation test> The raw material components used in each example are shown below. (Epoxy resin) Epoxy resin 1: Orthocresol novolac type epoxy resin (manufactured by DIC Corporation, product name "EPICRON N-670") Epoxy resin 2: Orthocresol novolac type epoxy resin (manufactured by DIC Corporation, product name "EPICRON N-660") Epoxy resin 3: Biphenyl type epoxy resin (Mitsubishi Chemical Corporation, YX-4000K)

[0080] (hardening agent) Hardener 1: Novolac-type phenol compound (Sumitomo Bakelite Co., Ltd., PR-51470) Hardener 2: Novolac-type phenol compound (Sumitomo Bakelite Co., Ltd., PR-51714) Hardener 3: Triphenolmethane type phenolic resin (MEH-7500, manufactured by Meiwa Kasei Co., Ltd.)

[0081] (Inorganic filler) Inorganic filler 1: Fused spherical silica (manufactured by Denka Co., Ltd., FB-950) Inorganic filler 2: Fused spherical silica (manufactured by Denka Co., Ltd., FB-105) Inorganic filler 3: Fused crushed silica (Fumitec Co., Ltd., FMT-15C) Inorganic filler 4: Glass fiber (manufactured by Nitto Boseki Co., Ltd., CS3E479) Inorganic filler 5: Crystal crushed silica (Tatsumori Co., Ltd., HFC-7) Inorganic filler 6: Fused spherical alumina (Denka Co., Ltd., DAB-45SI)

[0082] (Cure accelerator) Curing accelerator 1: Tetraphenylphosphonium 2,3-dihydroxynaphthalate Curing accelerator 2: 2-phenyl-4,5-dihydroxymethylimidazole (Shikoku Chemical Industry Co., Ltd., 2PHZ-PW)

[0083] (Release agent) Wax 1: Carnauba wax (TOWAX-132, manufactured by Toa Kasei Co., Ltd.)

[0084] (Silane coupling agent) Silane coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane (Toray Dow Corning Co., Ltd., CF-4083) (Coloring agent) Colorant 1: Carbon black (Mitsubishi Chemical Corporation, Carbon #5)

[0085] (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 70° C. to 110° C. Next, the resulting kneaded product was cooled and then pulverized to obtain a resin composition.

[0086] (Dielectric breakdown strength) The mesh sheet was impregnated with the resin composition obtained in each example and cured at 175°C for 3 minutes to obtain a mesh sheet-containing cured resin sheet having a thickness of 200 mm. Then, electrodes were attached to the top and bottom of the mesh sheet-containing cured resin sheet, and an insulation test (based on JIS C2300) was carried out under conditions of a temperature of 20°C and a humidity of 65%. The mesh sheet used had the same specifications as product (1) among the mesh sheets used in the evaluation of the self-supporting property.

[0087] <Evaluation Results> The results showed good self-supporting and insulating properties.

[0088] [Table 1] [Explanation of symbols]

[0089] 100 Motor 1 case 2 Rotors 4 Stator 5. Permanent magnets 6. Yoke 7 Teeth 8 Slots 9 Coil 41 Stator core 50 Insulating sheet 51 Seat storage section 52 Seat protrusion 62 Yoke wall 65 Resin sealing part 71 Teeth tip 72 Teeth wall 72 91 Coil body 92 First coil end 93 Second coil end

Claims

1. A stator for a rotating electric machine comprising: a coil accommodated in a slot; an insulating sheet disposed between a wall surface of the slot and the coil; and a sealing member provided by covering the coil with a thermosetting resin composition, The insulating sheet is provided in a mesh shape having a plurality of openings, the thermosetting resin composition is provided so as to infiltrate into the openings of the insulating sheet, The electrical insulation of the insulating sheet has a dielectric breakdown strength of 20 kV / mm or more, A stator, wherein an opening ratio of a surface of the insulating sheet due to the openings is 25% or more and 70% or less.

2. The stator according to claim 1 , wherein the insulating sheet has a heat resistance temperature of 100° C. or higher.

3. 3. The stator according to claim 1, wherein the insulating sheet has a thickness of 100 μm or more and 500 μm or less.

4. the thermosetting resin composition covers at least one end of the coil protruding from the slot; the insulating sheet is provided so as to protrude in an axial direction from the slot in a portion of the coil that is covered with the thermosetting resin composition, 3. The stator according to claim 1, wherein the protrusion amount of the insulating sheet is 0.1 mm or more and 10 mm or less.

5. 3. The stator according to claim 1, wherein the insulating sheet is a single-layer sheet selected from the group consisting of insulating paper, insulating film, nonwoven fabric, and mesh cloth, or a member in which an opening is provided in a sheet formed by stacking a plurality of sheets selected from the group consisting of insulating paper, insulating film, nonwoven fabric, and mesh cloth.

6. 3. The stator according to claim 1, wherein the minimum width of the opening is 0.05 mm or more and 3 mm or less.

7. The thermosetting resin composition comprises: Epoxy resin, A hardener; and an inorganic filler, 3. The stator according to claim 1, wherein the inorganic filler has a maximum diameter of 0.5 mm or less.

8. 3. The stator according to claim 1, wherein the thermosetting resin composition has a glass transition temperature Tg of 140° C. or higher.

9. A rotating electric machine comprising the stator according to claim 1 or 2.

10. A method for manufacturing a stator according to claim 1 or 2, comprising the steps of: an insulating sheet arrangement step of arranging a mesh-shaped insulating sheet along a wall surface inside the slot; a coil housing step of housing a coil in the slot in which the insulating sheet is disposed; a resin filling step of filling the slot with a thermosetting resin composition to seal the coil with the thermosetting resin composition and to allow the thermosetting resin composition to penetrate into the opening of the insulating sheet; A method for manufacturing a stator comprising the steps of:

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