Method for manufacturing thermosetting resin composition and stator

Abstract

The present invention provides a thermosetting resin composition for filling the space (88) formed between a mold core (80) (insert) inserted into a groove (8) of a stator (4) and the wall surface of the groove (8) (inner wall surface (72) of the tooth (7) and the inner wall surface (62) of the yoke (6)) to form an insulating layer. The thermosetting resin composition contains an epoxy resin, a curing agent, an inorganic filler and a wax (release agent). The wax contains a higher fatty acid ester or a higher fatty acid amide. The amount of the higher fatty acid ester or the higher fatty acid amide is less than 1.0% by mass relative to the total amount of the thermosetting resin composition.

Description

Technical Field

[0001] This invention relates to thermosetting resin compositions and stators. More specifically, it relates to thermosetting resin compositions used as encapsulation materials for stator cores and stators comprising the thermosetting resin composition as an encapsulation material. Background Technology

[0002] As a technology for using resin materials in stator cores, there is the technology described in Patent Document 1 (Japanese Patent Application Publication No. 2003-284277). Patent Document 1 describes a rotary motor comprising: a stator obtained by winding a plurality of coils at predetermined intervals on a stator core formed by stacking a plurality of electromagnetic steel plates; a rotor that is rotatably held relative to the stator; and a cooling frame that can fix the stator. In the rotary motor, a highly thermally conductive composite material made of a thermosetting resin with an anisotropic structure in the resin composition is disposed in the slots of the winding portion that forms the stator. With this structure, a rotary motor with good heat dissipation can be provided that easily conducts heat generated in the coils.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2003-284277 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] The coil is inserted into a slot in the stator, but to ensure insulation between the coil and the slot, a resin layer is sometimes formed on the wall of the slot before the coil is inserted. In the process of forming this resin layer, a mold core (also called a blade) is placed inside the slot, and a resin composition is filled into the space formed by the slot wall and the mold core. After a certain period of time, the mold core is removed. During the removal of the mold core, undesirable conditions such as deformation of the resin composition around the mold core sometimes occur, making it difficult to increase the extraction speed. Therefore, from a productivity point of view, a solution is needed.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a technique that can improve productivity when a mold core is inserted into a groove and a resin layer is formed on the wall of the groove.

[0009] Means for solving technical problems

[0010] According to the present invention, the following technical solution is provided.

[0011] <1> A thermosetting resin composition for filling the space formed between a mold core insert and the wall of a slot inserted into a stator to form an insulating layer, the thermosetting resin composition being characterized by comprising:

[0012] Epoxy resin;

[0013] Curing agent;

[0014] Inorganic filler materials; and

[0015] wax,

[0016] The wax contains higher fatty acid esters or higher fatty acid amides, wherein the amount of the higher fatty acid esters or higher fatty acid amides is less than 1.0% by mass relative to the total thermosetting resin composition.

[0017] <2> A method for manufacturing a stator, characterized in that:

[0018] An insulating layer is formed on the wall of the tank using the thermosetting resin composition described in <1>.

[0019] The method for manufacturing the stator includes:

[0020] In the core configuration step, a insert-shaped mold core is inserted into the groove, forming a filling space between the groove wall and the mold core for filling the thermosetting resin composition; and

[0021] The resin filling process involves filling the filling space with the thermosetting resin composition.

[0022] <3> The stator manufacturing method according to <2> is characterized in that: the surface roughness Ra of the mold core is less than 10 μm.

[0023] <4> The stator manufacturing method according to <2> or <3> is characterized in that: the surface of the mold core has a coating.

[0024] <5> The method for manufacturing a stator according to any one of <2> to <4> is characterized in that: the process after the resin filling process includes a mold core removal process of extracting and removing the mold core.

[0025] <6> The stator manufacturing method according to <5> is characterized in that: in the mold core removal process, the extraction force F when removing the mold core is less than 250 kgf.

[0026] <7> The stator manufacturing method according to <6> is characterized in that: in the mold core removal process, the ratio of the surface area S of the mold core to the extraction force F, F / S, is 3.6 kgf / cm².2 the following.

[0027] <8> The method for manufacturing a stator according to any one of <5> to <7> is characterized in that: the mold core removal process is performed in the original molding state.

[0028] <9> The method for manufacturing a stator according to any one of <2> to <8> is characterized in that: the glass transition temperature Tg of the cured thermosetting resin composition is 120°C or higher.

[0029] Invention Effects

[0030] The present invention was made in view of the above circumstances, and is able to provide a technique that can improve productivity when a mold core is inserted into a groove and a resin layer is formed on the wall of the groove. Attached Figure Description

[0031] Figure 1 It is a cross-sectional view in a direction perpendicular to the direction of the motor's rotation axis.

[0032] Figure 2 This is a longitudinal cross-sectional view of the motor along its rotational axis.

[0033] Figure 3 It is a diagram showing the enlarged view of the area around the groove.

[0034] Figure 4 It is a cross-sectional view showing the inside of the groove.

[0035] Figure 5 This is a flowchart illustrating the manufacturing method of the stator.

[0036] Figure 6 This diagram illustrates the changes in the state of the tank during the resin layer formation process.

[0037] Figure 7 This diagram illustrates the changes in the state of the tank during the resin layer formation process.

[0038] Figure 8 This is a diagram showing the slots of the stator simulation model of the embodiment.

[0039] Figure 9 This is a diagram showing the mold core of an embodiment. Detailed Implementation

[0040] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. In all the drawings, the same reference numerals are used to denote the same constituent elements, and descriptions are omitted where appropriate. Furthermore, in this specification, the numerical range "a to b" means "a or more, b or less".

[0041] <Outline>

[0042] In this embodiment, a technique is provided that improves productivity when a mold core is inserted into a stator slot and a resin layer is formed on the wall of the slot. Therefore, a wax (release agent) is included in the thermosetting resin composition used to form the resin layer. The wax contains a higher fatty acid ester or a higher fatty acid amide, and the amount of the higher fatty acid ester or higher fatty acid amide is 1.0% by mass or less relative to the overall thermosetting resin composition. Furthermore, this improves the extractability of the insert-shaped mold core used to form the resin layer from the thermosetting resin composition. Detailed explanation follows.

[0043] Furthermore, the stator of this embodiment can be used as a rotating electric motor (electric motor, generator, or electric motor / generator hybrid) in an electric motor. Hereinafter, as one embodiment, the application of the motor will be described.

[0044] <Motor>

[0045] Figure 1 The diagram schematically shows a cross-sectional view in a direction perpendicular to the rotation axis of the motor 100. Figure 2 The diagram schematically shows a cross-sectional view of the rotation axis of the motor 100. Figure 3 It is to surround the groove ( Figure 1 The enlarged view of region X schematically shows a cross-sectional view of the portion of coil 9 protruding from the end of slot 8. Figure 4 This is a diagram showing the interior of slot 8. Figure 3 AA section diagram.

[0046] The motor 100 includes: a housing 1; and a rotor 2, a stator 4, and a coil 9 housed inside the housing 1.

[0047] <Outer Shell>

[0048] The outer casing 1 is configured to have a cylindrical portion 1a and side plate portions 1b and 1c that close the axial ends of the cylindrical portion 1a. As the material of the outer casing 1, for example, aluminum alloy (casting), resin material, or a combination of these materials can be used.

[0049] <Rotor>

[0050] like Figure 1 , Figure 2 As shown, rotor 2 is housed inside housing 1. Figure 2 As shown, a rotating shaft 3 is mounted at the center of the rotor 2 as an output shaft. The two ends of the rotating shaft 3 are supported by bearings 3a on the side plates 1b and 1c, respectively. Thus, the rotor 2 can rotate around the rotating shaft 3.

[0051] A permanent magnet 5 is built into rotor 2. Specifically, as follows: Figure 1As shown, 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 different from each other.

[0052] <Stator>

[0053] The stator 4 has a stator core 41 and a coil 9 encapsulated in a slot 8.

[0054] In the stator core 41, multiple electromagnetic steel plates are stacked and tightly fixed in the axial direction, such as... Figure 1 As shown, when viewed from the axial end, a magnetic yoke 6 arranged in a ring shape and a plurality of teeth 7 extending from the magnetic yoke 6 toward the rotor 2 (inner circumferential side) are provided. The plurality of teeth 7 are arranged at equal intervals in the circumferential direction. Here, as... Figure 1 As shown, 24 teeth 7 are provided. Grooves 8 are provided between each tooth 7. Furthermore, a resin layer 50, which is surrounded by a resin composition and covered to form a thin wall, is provided on the tooth 7.

[0055] <Coil>

[0056] As an example, the coil 9 is in the shape of a flat U-shaped wire and is wound across the toothed portion 7 and housed in two spaced-apart slots 8. The coil 9 may be housed in a bushing member disposed in the slots 8 in a distributed winding manner, or it may be housed without a bushing member. The coil 9 has: a coil body with a rectangular cross-section that is a good conductor such as copper; and a resin coating layer covering the surface of the coil body. The resin coating layer can be made of the same material as the resin material described later as the resin layer 50.

[0057] <Teeth>

[0058] The teeth 7 are provided corresponding to the permanent magnets 5 of the rotor 2. By energizing each coil 9 in sequence, the rotor 2 can be rotated by the attraction and repulsion of the corresponding permanent magnets 5.

[0059] The tooth 7 has a large circumferential width on its outer periphery and a small width on its inner periphery, and the tooth 7 is formed to taper towards the inner periphery. At the end of the tooth 7 on its inner periphery, a tooth tip 71 is formed that is circumferentially opposite to the tooth 7 in a manner that reduces the width of the groove 8.

[0060] <groove>

[0061] Groove 8 is the space between adjacent teeth 7, such as... Figure 3 and Figure 4As shown, the inner wall surfaces 72 of the radially opposite teeth 7 are arranged in a parallel manner. The front ends 71 ​​of the teeth form an inner peripheral opening of the groove 8. The groove 8 has: a plurality of coils 9 disposed on the outer peripheral side (the side of the yoke 6); a resin layer 50; and a resin encapsulation portion 65 filled in the space within the groove 8 excluding the coils 9 and the resin layer 50.

[0062] <Resin Layer>

[0063] like Figure 3 and Figure 4 As shown, the resin layer 50 is integrally surrounded and covered by a resin composition around and covers the periphery of the tooth 7, and has: an inner surface resin layer 51 covering the inner wall surface 72 of the tooth 7; an outer surface resin layer 52 covering the upper surface 75a and the lower surface 75b of the tooth 7; and an inner surface resin layer 53 covering the inner wall surface 62 of the yoke 6.

[0064] The resin layer 50 is formed by insert molding to surround and cover the teeth 7 in a thin-walled manner, thereby tightly fixing the stator 4, and more specifically the multiple stacked electromagnet plates in the teeth 7. Alternatively, the resin layer 50 does not necessarily need to surround the teeth 7 in a thin-walled manner, and the resin layer 52 on the outer surface of the teeth can be omitted. By having a resin layer 51 on the inner surface of the teeth and a resin layer 53 on the inner surface of the yoke, insulation between the coil 9 and the inner wall surfaces of the slot 8 (the inner wall surface 72 of the teeth 7 and the inner wall surface 62 of the yoke 6) can be ensured.

[0065] 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, more preferably 150 μm or more. The upper limit of the thickness is preferably 400 μm or less, more preferably 300 μm or less. The thicknesses of the resin layer 51 on the inner surface of the tooth, the resin layer 52 on the outer surface of the tooth, and the resin layer 53 on the inner surface of the magnetic yoke can be the same or different.

[0066] From the viewpoint of ensuring the flowability of the resin composition in the extremely narrow section between the mold (mold core 80) and the wall of the groove 8 relative to the stator shaft length (i.e., the thickness of the stator 4) during insert molding, the lower limit of the thickness is preferably set within the range described above.

[0067] From the viewpoint of improving the space utilization efficiency within the slot 8 and ensuring the degree of freedom in the size of the usable coil 9 and the performance of magnetic flux density in the structure in which the coil 9 is mounted, the upper limit of the thickness is preferably set within the range described above.

[0068] <Properties of the Resin Layer>

[0069] The physical properties of the cured resin material constituting the resin layer 50 are as follows.

[0070] The thermal conductivity of the cured resin material is 0.5 W / (m•K) or higher. The lower limit of the thermal conductivity is preferably 1.0 W / (m•K) or higher, more preferably 2 W / (m•K) or higher. The upper limit of the thermal conductivity is not particularly limited, but a practical value is 10 W / (m•K).

[0071] The glass transition temperature (Tg) of the resin composition of the resin layer 50 is 120°C or higher, preferably 140°C or higher, and more preferably 160°C or higher. By setting the glass transition temperature (Tg) to the above range, the motor 100 can be used at high temperatures, and the resistance to heating of the coil 9 can be enhanced, enabling the motor 100 to be used with high output.

[0072] The resin composition of resin layer 50 will be described in detail below.

[0073] <Materials of the Resin Layer>

[0074] The resin composition of the resin layer 50 preferably contains a thermosetting resin (A), a filler (B), and a curing agent (C).

[0075] [Thermosetting resin (A)]

[0076] Examples of thermosetting resins (A) include epoxy resins, cyanate ester resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins. One of these thermosetting resins (A) may be used alone or in combination with two or more.

[0077] From the viewpoint of having high insulation properties, epoxy resin, phenolic resin, and phenoxy resin are preferred as thermosetting resin (A). From the viewpoint of ensuring flow in extremely narrow sections during molding, epoxy resin is particularly preferred.

[0078] Examples of epoxy resins include 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-phenylene diisopropylidene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylene diisopropylidene) bisphenol type epoxy resin), bisphenol Z type epoxy resin (4,4'-cyclohexylene bisphenol type epoxy resin), etc.; phenolic varnish type epoxy resin, cresol varnish type epoxy resin, triphenolic methane type phenolic varnish type epoxy resin, tetraphenolic varnish type epoxy resin, etc. Phenolic varnish-type epoxy resins include phenolic ethane type epoxy resins and phenolic varnish-type epoxy resins with polycyclic aromatic hydrocarbon structures; biphenyl type epoxy resins; xylene-type epoxy resins and biphenyl arylane type epoxy resins; naphthalene-type epoxy resins include naphthalene ether type epoxy resins, naphthol type epoxy resins, naphthiodiol type epoxy resins, difunctional to tetrafunctional naphthalene epoxy resins, binaphthalene type epoxy resins, and naphthalene arylane type epoxy resins; anthracene type epoxy resins; phenoxy type epoxy resins; dicyclopentadiene type epoxy resins; norbornene type epoxy resins; adamantane type epoxy resins; and fluorene type epoxy resins. One of these types can be used alone, or two or more can be used in combination.

[0079] From the viewpoint of further improving heat resistance and insulation reliability, epoxy resins are preferably selected from one or more of bisphenol type epoxy resins, phenolic varnish type epoxy resins, biphenyl type epoxy resins, arylalkylene type epoxy resins, naphthalene type epoxy resins, anthracene type epoxy resins, and dicyclopentadiene type epoxy resins.

[0080] Examples of phenolic resins include phenolic varnish resins such as phenol, cresol, and bisphenol A varnish resins, as well as methyl phenolic resins. One type can be used alone, or two or more can be used in combination.

[0081] Among phenolic resins, phenolic varnish resin is preferred.

[0082] The content of thermosetting resin (A) relative to the total amount of the resin composition of resin layer 50 is preferably 1% by mass or more, more preferably 5% by mass or more. On the other hand, this content relative to the total amount of the resin composition of resin layer 50 is preferably 30% by mass or less, more preferably 20% by mass or less.

[0083] When the content of thermosetting resin (A) is above the lower limit mentioned above, the operability of the total amount of resin composition of resin layer 50 is improved, the inner surface resin layer (tooth inner surface resin layer 51, magnetic yoke inner surface resin layer 53) is easily formed, and the strength of the inner surface resin layer (tooth inner surface resin layer 51, magnetic yoke inner surface resin layer 53) is improved.

[0084] When the content of thermosetting resin (A) is below the above-mentioned upper limit, the coefficient of linear expansion and elastic modulus of the inner surface resin layer (tooth inner surface resin layer 51, magnetic yoke inner surface resin layer 53) are further improved, and the thermal conductivity is further improved.

[0085] [Fill Material (B)]

[0086] The filler material (B) in this embodiment is used from the viewpoint of improving the thermal conductivity of the resin layer 50 (more specifically the inner surface resin layer (tooth inner surface resin layer 51, magnetic yoke inner surface resin layer 53)) and obtaining strength.

[0087] As filler material (B), inorganic filler materials are preferred, and thermally conductive fillers are particularly preferred. More specifically, from the viewpoint of achieving a balance between thermal conductivity and electrical insulation, examples of filler materials (B) include silicon dioxide, alumina, boron nitride, aluminum nitride, and silicon carbide. These can be used alone or in combination of two or more. Among them, alumina and boron nitride are preferred as filler materials (B).

[0088] The content of filler material (B), i.e. the content of the filler mentioned above, is preferably 60% by mass or more relative to the total amount of the resin composition.

[0089] [Curing agent (C)]

[0090] When the resin composition uses epoxy resin or phenolic resin as the thermosetting resin (A), it preferably also contains a curing agent (C).

[0091] As the curing agent (C), one or more selected from curing catalyst (C-1) and phenolic curing agent (C-2) can be used.

[0092] Examples of solidification catalysts (C-1) include organometallic salts such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, cobalt diacetylacetonate (II), and cobalt triacetylacetonate (III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; imidazoles such as 2-phenyl-4-methylimidazolium, 2-ethyl-4-methylimidazolium, 2,4-diethylimidazolium, 2-phenyl-4-methyl-5-hydroxyimidazolium, and 2-phenyl-4,5-dihydroxymethylimidazolium; organophosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphine tetraphenylborate, triphenylphosphine-triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenolic compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid, or mixtures thereof. As a curing catalyst (C-1), it can be used alone, including derivatives of these substances, or it can be used in combination with two or more derivatives of these substances.

[0093] The content of the curing catalyst (C-1) is not particularly limited, but is preferably 0.001% by mass or more and 1% by mass or less relative to the total amount of the resin composition.

[0094] Furthermore, examples of phenolic curing agents (C-2) include phenolic varnish resins such as phenolic resin, cresol varnish resin, triphenol methane varnish resin, naphthol varnish resin, and aminotriazine varnish resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl resins such as phenolic aralkyl resins with a phenylene skeleton and / or a biphenylene skeleton, and naphthol aralkyl resins with a phenylene skeleton and / or a biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and methyl phenolic resins. These can be used alone or in combination with two or more.

[0095] From the perspective of increasing the glass transition temperature and reducing the coefficient of linear expansion, phenolic varnish-type phenolic resin or methyl phenolic resin is preferred as the phenolic curing agent (C-2).

[0096] The content of the phenolic curing agent (C-2) is not particularly limited, but it is preferably 1% by mass or more, more preferably 5% by mass or more, relative to the total amount of the resin composition. On the other hand, this content is preferably 30% by mass or less, more preferably 15% by mass or less, relative to the total amount of the resin composition.

[0097] [Coupled Agent (D)]

[0098] The resin composition may contain a coupling agent (D). The coupling agent (D) can improve the wettability of the interface between the thermosetting resin (A) and the filler material (B).

[0099] There are no particular limitations on the coupling agent (D), but it is preferred to use one or more coupling agents selected from epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate coupling agents and silicone oil coupling agents.

[0100] The content of coupling agent (D) is not particularly limited, but it is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, relative to 100% by mass of filler material (B). On the other hand, this content is preferably 3% by mass or less, more preferably 2% by mass or less, relative to 100% by mass of filler material (B).

[0101] [Phenoxy resin (E)]

[0102] The resin composition may also contain phenoxy resin (E). By containing phenoxy resin (E), the flexural strength of the resin layer 50 can be improved, and the elastic modulus can be reduced, thereby improving the stress relief of the resin layer 50.

[0103] Furthermore, when phenoxy resin (E) is present, the viscosity increases and the fluidity decreases, which can suppress the formation of voids. In addition, when the resin layer 50 is used in close contact with a metal part (i.e., the tooth 7 or the magnetic yoke 6), the adhesion between the cured metal and the resin composition can be improved.

[0104] Examples of phenoxy resins (E) include phenoxy resins having a bisphenol backbone, phenoxy resins having a naphthalene backbone, phenoxy resins having an anthracene backbone, and phenoxy resins having a biphenyl backbone. Furthermore, phenoxy resins having structures with multiple of these backbones can also be used.

[0105] The content of phenoxy resin (E) relative to the total amount of the resin composition is preferably, for example, 3% by mass or more and 10% by mass or less.

[0106] [Wax (mold release agent)]

[0107] The resin composition contains wax. This improves the release properties from the molded mold core 80. Examples of waxes include natural waxes such as carnauba wax, synthetic waxes such as lignite ester wax or oxidized polyethylene wax, higher fatty acids such as zinc stearate and their metal salts, paraffin wax, and higher fatty acid amides. These can be used alone or in combination. It is preferable to contain higher fatty acid esters or higher fatty acid amides, and particularly preferable to contain lignite ester wax.

[0108] Examples of hydrocarbon waxes include paraffin waxes with 24 or more carbon atoms, olefin waxes with 26 or more carbon atoms, alkylbenzenes with 28 or more carbon atoms, and microcrystalline waxes.

[0109] Examples of high-grade fatty acids include lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, hexacosanoic acid, and linoleic acid, which are high-grade saturated fatty acids with 12 or more carbon atoms, as well as oleic acid, linoleic acid, linolenic acid, transoleic acid, octadecenoic acid, arachidonic acid, codoleic acid, erucic acid, and octadecenoic acid, which are unsaturated fatty acids with 18 or more carbon atoms.

[0110] Waxes derived from higher fatty acids include higher fatty acid esters, higher fatty acid amides, and higher fatty acid salts (metallic soaps).

[0111] Higher fatty acid esters are esters of the aforementioned higher fatty acids with monohydric or polyhydric alcohols. Examples of monohydric alcohols include octanol, lauryl alcohol, myristol, palmitol, stearyl alcohol, and behenol, while examples of polyhydric alcohols include ethylene glycol, propylene glycol, butylene glycol, glycerol, pentaerythritol, and sorbitol.

[0112] Examples of higher fatty acid esters include stearate, pentaerythritol tetrastearate, glyceryl monostearate, glyceryl behenate monostearate, and lignite ester wax.

[0113] Examples of higher fatty acid amides include saturated higher fatty acid amides such as laurylamide, palmitamide, stearamide, and behenamide; unsaturated higher fatty acid amides such as erucamide, oleamide, brassinoamide, and transoleamide; and higher fatty acid diamides such as methylene distearate, ethylene distearate, and ethylene dioleate (including saturated or unsaturated higher fatty acid alkylamides such as higher fatty acid methylamide and higher fatty acid ethylamide).

[0114] When using wax (release agent), its content in the total resin molding material is preferably 0.01 to 3% by mass, more preferably 0.05 to 2% by mass. This reliably improves the release properties. As a result, the molding accuracy of the inner surface resin layer of resin layer 50 (more specifically, the inner surface resin layer 51 of the teeth and the inner surface resin layer 53 of the magnetic yoke) can be improved.

[0115] When the wax (release agent) contains higher fatty acid esters or higher fatty acid amides, the amount of the higher fatty acid esters or higher fatty acid amides relative to the overall thermosetting resin composition is 1.0% by mass or less. By keeping the amount of the higher fatty acid esters or higher fatty acid amides as wax (release agent) relative to the overall thermosetting resin composition at 1.0% by mass or less, it is possible to balance the extraction of the mold core 80 (insert) and the tightness of its fit with the stator core 41. The upper limit of the amount of the higher fatty acid esters or higher fatty acid amides is preferably 0.8% by mass or less, more preferably 0.6% by mass or less. The lower limit is, for example, 0.1% by mass or more, preferably 0.2% by mass or more, more preferably 0.3% by mass or more.

[0116] [Other ingredients]

[0117] The resin composition may also contain antioxidants, homogenizers, etc., without impairing the effects of the present invention.

[0118] <Resin Encapsulation Department>

[0119] A resin encapsulation part 65 is disposed inside the groove 8 (more specifically, between the resin layer 50 and the coil 9) to encapsulate (seal) the coil 9. The resin encapsulation part 65 can be provided by insert molding or as a separate component. The resin material used in the resin encapsulation part 65 can be the same material described for the resin material used as the resin layer 50.

[0120] <Stator Manufacturing Method>

[0121] The manufacturing method of the stator 4 in this embodiment will be described. Figure 5 This is a flowchart illustrating the manufacturing method of stator 4.

[0122] First, prepare the stator 4 by stacking and fixing multiple electromagnetic steel plates axially (stator preparation step S10).

[0123] Next, a mold core 80 is placed in the groove 8, and an insulating resin composition is integrally wrapped around and covered by insert molding to form a resin layer 50 (resin layer forming step S20).

[0124] Next, coils 9 are arranged in the groove 8 where the resin layer 50 is provided (coil arrangement process S30). After all the coils 9 are housed, resin material is filled into the area on the inner periphery of the groove 8 to obtain the resin encapsulation part 65 (coil encapsulation process S40).

[0125] Next, referring to the flowchart above and Figure 6 and Figure 7 The resin layer formation process S20 will be described in more detail. Figure 6 and Figure 7 This is a diagram showing the change in the state of the tank during the resin layer formation process S20. Figure 6 It is a cross-sectional view obtained by cutting with a plane perpendicular to the axis. Figure 7 Is with Figure 3 A cross-sectional view of the portion corresponding to section AA.

[0126] The resin layer forming process S20 includes a core configuration process S21, a resin filling process S22, and a mold core removal process S23.

[0127] like Figure 6 (a) and Figure 7 As shown in (a), the core configuration step S21 is a step of inserting a insert-shaped mold core 80 into the groove 8. In this embodiment, the mold core 80 is inserted into the groove 8 from the upper side as shown in the figure. At this time, the upper and lower ends of the mold core 80 protrude from the upper and lower ends of the groove 8.

[0128] Through the core configuration process S21, a space 88 for filling the thermosetting resin composition is formed between the wall surface of the groove 8 (the inner wall surface 72 of the toothed part 7 and the inner wall surface 62 of the magnetic yoke part 6) and the mold core 80.

[0129] Next, as Figure 6 (b) and Figure 7As shown in (b), the resin filling process S22 is the process of filling the space 88 formed by the core configuration process S21 with the above-mentioned thermosetting resin composition.

[0130] Next, as Figure 6 (c) and Figure 7 As shown in (c), the mold core removal process S23 is a process of extracting and removing the mold core 80 after the resin filling process S22. This process is performed in the so-called molded state without post-curing. For example, as will be discussed later... Figure 9 As with the mold core 80 used in the illustrated embodiment, an operating opening 87 is provided near the upper end 80a of the mold core 80. By installing a predetermined jig at this opening 87, the mold core 80 is pulled out in the upward direction as shown in the figure.

[0131] When the mold core removal process S23 ends, as Figure 6 (d) and Figure 7 As shown in (d), a resin layer 50 is formed on the wall surface of the groove 8 (the inner wall surface 72 of the toothed part 7 and the inner wall surface 62 of the magnetic yoke part 6).

[0132] <Mold Core>

[0133] The mold core 80 used in the resin layer forming process S20 will be described.

[0134] The mold core 80 can be appropriately shaped to correspond with the shape of the groove 8 and the resin layer 50 to be formed, typically in the form of a long, thin-walled insert. The mold core 80 can be made of common mold steel, such as SKD-11 (JIS standard). The surface of the mold core 80 (the surface in contact with the resin layer 50) has been smoothed. Therefore, deformation or other effects on the resin layer 50 can be avoided when the mold core 80 is removed.

[0135] Furthermore, the water contact angle of the surface of the mold core 80 is 90° or more, preferably 95° or more, and more preferably 100° or more. The actual upper limit of the water contact angle is 170° or less, preferably 160° or less, and more preferably 150° or less. The water contact angle is measured according to JIS R3257, for example, using a contact angle meter. As the measurement method, known methods such as the width-height method (θ / 2 method), the Young-Laplace method, or the ellipse method can be used.

[0136] By ensuring that the amount of higher fatty acid esters or higher fatty acid amides as waxes (release agents) contained in the material (thermosetting resin composition) of the resin layer 50 is 1.0% by mass or less, and by ensuring that the water contact angle of the surface of the mold core 80 is within the above range, it is possible to ensure the good extractability of the mold core 80 while ensuring the tightness between the resin layer 50 and the stator core 41.

[0137] Furthermore, the surface roughness Ra of the mold core 80 is 10 μm or less, preferably 5 μm or less, and more preferably 1 μm or less. The lower limit of the surface roughness Ra is not particularly limited, but the actual range is 0.01 μm or more, preferably 0.05 μm or more, and more preferably 0.1 μm or more.

[0138] The surface roughness Ra is measured in accordance with JIS B 0601-2001. By smoothing the surface of the mold core 80 so that the surface roughness Ra of the mold core 80 is within the above range, it is possible to ensure good extractability of the mold core 80 while ensuring the tightness between the resin layer 50 and the stator core 41.

[0139] In addition, it is sufficient that at least one of the water contact angle and surface roughness Ra of the mold core 80 surface meets the above-mentioned range. However, by satisfying both conditions, it is possible to balance the extraction of the mold core 80 and the tightness between the resin layer 50 and the stator core 41.

[0140] The surface of the mold core 80 may have a coating.

[0141] As a coating, chromium plating, fluorine coating, PVD (Physical Vapor Deposition) coating, ceramic coating, etc. can be used.

[0142] By applying the coating as described above to the surface of the mold core 80, the water contact angle and surface roughness Ra of the mold core 80 surface can be easily adjusted to the aforementioned range. Furthermore, the type and thickness of the coating are not limited to the examples described above; various coatings capable of setting the water contact angle and surface roughness within appropriate ranges can be used.

[0143] In the mold core removal process S23, the extraction force F when removing the mold core 80 is 250 kgf or less, preferably 200 kgf or less, and more preferably 150 kgf or less. The lower limit is, for example, 25 kgf or more, preferably 50 kgf or more, and more preferably 75 kgf or more.

[0144] Furthermore, in the mold core removal process S23, the ratio of the surface area S1 of the mold core 80 to the extraction force F, F / S1, is 3.6 kgf / cm². 2 The preferred value is 2.9 kgf / cm³. 2The following is more preferably 2.2 kgf / cm 2 The lower limit is, for example, 0.4 kgf / cm³. 2 The above values ​​are preferably 0.8 kgf or more, and more preferably 1.2 kgf or more. By ensuring that the extraction force F of the mold core 80 and the ratio F / S1 of the surface area S1 to the extraction force F are within the above ranges, the force acting on the resin layer 50 during extraction can be suppressed, preventing the resin layer 50 from deforming or causing other defects. This can be achieved by ensuring that the material of the resin layer 50 (especially the selection and amount of wax) and the surface condition of the mold core 80 (water contact angle and surface roughness Ra) are as described above.

[0145] <Summary of Implementation Methods>

[0146] The features of this embodiment are summarized below.

[0147] <1> A thermosetting resin composition for filling the space 88 formed between a mold core 80 (insert) inserted into a slot 8 of a stator 4 and the wall surface of the slot 8 (inner wall surface 72 of the tooth 7, inner wall surface 62 of the yoke 6) to form an insulating layer, the thermosetting resin composition being characterized in that it contains:

[0148] Epoxy resin;

[0149] Curing agent;

[0150] Inorganic filler materials; and

[0151] Wax (release agent)

[0152] The wax contains higher fatty acid esters or higher fatty acid amides, wherein the amount of the higher fatty acid esters or higher fatty acid amides is less than 1.0% by mass relative to the total thermosetting resin composition.

[0153] <2> A method for manufacturing a stator 4, characterized in that:

[0154] An insulating layer (resin layer 50) is provided on the wall surface of the groove 8 (inner wall surface 72 of the toothed part 7 and inner wall surface 62 of the magnetic yoke part 6) using the thermosetting resin composition described in <1>.

[0155] The method for manufacturing the stator 4 includes:

[0156] In the core configuration step S21, a insert-shaped mold core 80 is inserted into the groove 8, forming a filling space (space 88) between the wall of the groove 8 and the mold core 80 for filling the thermosetting resin composition; and

[0157] In the resin filling process S22, the thermosetting resin composition is filled into the filling space (space 88).

[0158] <3> The manufacturing method of stator 4 according to <2> is characterized in that: the surface roughness Ra of the mold core 80 is less than 10 μm.

[0159] <4> The stator manufacturing method according to <2> or <3> is characterized in that: the surface of the mold core 80 has a coating.

[0160] <5> The method for manufacturing the stator 4 according to any one of <2> to <4> is characterized in that: the process after the resin filling process S22 includes a mold core removal process S23 in which the mold core 80 is extracted and removed.

[0161] <6> The method for manufacturing the stator 4 according to <5> is characterized in that: in the mold core removal process S23, the extraction force F when removing the mold core 80 is less than 250 kgf.

[0162] <7> The method for manufacturing the stator 4 according to <6> is characterized in that: in the mold core removal step S23, the ratio F / S1 of the surface area S1 of the mold core 80 to the extraction force F is 3.6 kgf / cm². 2 the following.

[0163] <8> The method for manufacturing the stator 4 according to any one of <5> to <7> is characterized in that: the mold core removal process S23 is performed in the original molding state.

[0164] <9> The method for manufacturing stator 4 according to any one of <2> to <8> is characterized in that: the glass transition temperature Tg of the cured thermosetting resin composition is 120°C or higher.

[0165] The embodiments of the present invention have been described above, but these are merely examples of the present invention, and various configurations other than those described above may also be used.

[0166] Example

[0167] The present invention will now be described in detail using examples, but the invention is not limited to these examples in any way. In the following examples, evaluation 1 (Example 1, Comparative Example 1) related to thermosetting resin compositions and evaluation 2 (Examples 2, 3, 4) related to mold cores are given.

[0168] <Evaluation 1>

[0169] In Evaluation 1, a thermosetting resin composition corresponding to the resin layer 50 of the embodiment is illustrated.

[0170] The following shows the raw material components used in Example 1 and Comparative Example 1.

[0171] (Inorganic filler material)

[0172] •Inorganic filler material 1: Molten spherical alumina (manufactured by Micron, Inc., average particle size 20 μm)

[0173] • Inorganic filler material 2: Molten spherical silica (manufactured by Tokuyama Corporation, average particle size 0.2μm)

[0174] • Inorganic filler material 3: molten spherical alumina (manufactured by ADMATECHS COMPANY LIMITED, average particle size 0.6μm)

[0175] (Coloring agent)

[0176] • Colorant 1: Carbon black

[0177] (Coupled agent)

[0178] • Coupling agent 1: N-phenyl-3-aminopropyltrimethoxysilane

[0179] • Coupling agent 2: 3-Mercaptopropyltrimethoxysilane

[0180] (Epoxy resin)

[0181] • Epoxy Resin 1: Biphenyl type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX4000HK)

[0182] • Epoxy Resin 2: Triphenolmethane-type phenolic resin (manufactured by Mitsubishi Chemical Corporation, YL6677)

[0183] (Curing agent)

[0184] • Hardener 1: Phenolic varnish-type phenolic compound (manufactured by Sumitomo Bakelite Co., Ltd.)

[0185] (Curing accelerator)

[0186] • Curing accelerator 1: Tetraphenylphosphonium-4,4'-sulfonyl diphenol salt

[0187] • Curing Accelerator 2: Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate

[0188] (Wax (mold release agent))

[0189] • Wax 1: Carnauba wax (manufactured by AIR WATER INC.)

[0190] • Wax 2: Linaloic acid derivative (manufactured by Clariant Japan KK, LICOWAXE)

[0191] • Wax 3: Diethanolamine·Dibrownate

[0192] (ion scavenger)

[0193] • Ion scavenger 1: Hydrotalcite (manufactured by Kyowa Chemical Industry Co., Ltd.)

[0194] (Other additives)

[0195] • Triazole compound 1: Triazole compound (manufactured by Shikoku Chemical Corporation)

[0196] (Low-stress materials)

[0197] • Organosilicon resin: Silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., KR-480)

[0198] • Organosilicon resin: Epoxy-polyether modified silicone oil (manufactured by Dow Corning Co., Ltd., FZ-3730)

[0199] (Preparation of resin composition)

[0200] First, the raw materials are mixed at room temperature using a mixer according to Table 1, and then kneaded at a temperature between 70°C and 110°C. Next, the resulting mixture is cooled and then pulverized to obtain the resin composition.

[0201] The resin compositions obtained in each example were subjected to the following determinations. The results are shown in Table 1.

[0202] (Glass transition temperature Tg)

[0203] For each example, the glass transition temperature of the cured resin composition was determined as follows: First, the encapsulation resin composition was injection 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 5 minutes to obtain a test piece measuring 15 mm × 3 mm × 4 mm. Next, the temperature was measured using a thermomechanical analysis apparatus (Seiko Instruments Inc., TMA100) at a temperature range of 40°C to 300°C and a heating rate of 5°C / min. The glass transition temperature was calculated based on the measurement results.

[0204] (thermal conductivity)

[0205] The resin compositions obtained in each example were injection 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 a cured body of 10 mm × 10 mm × 1 mm.

[0206] The thermal conductivity of the cured material is calculated using the following formula, based on the thermal diffusivity (α) determined by the laser flash method (half-time method), the specific heat (Cp) determined by the DSC method, and the density (ρ) determined according to JIS K 6911. The unit of thermal conductivity is W / m•K.

[0207] Thermal conductivity [W / m•K] = α [mm 2 / s]×Cp[J / kg•K]×ρ[g / cm 3 ]

[0208] [Table 1]

[0209]

[0210] <Rating 2>

[0211] In Evaluation 2, regarding the mold core 80 (insert) of the embodiment, three mold cores (inserts) were prepared, and the following evaluation items were evaluated. The surface roughness Ra, extraction force F, and extraction force F / surface area S were measured as evaluation items. The evaluation results are shown in Table 2.

[0212] (Stator simulation model)

[0213] Figure 8 The diagram shows the shape of the slot in the stator simulation model used to measure the extraction force F and the ratio of extraction force F to surface area S. One slot is shown here.

[0214] The dimensions of the groove are as follows.

[0215] Slot width (L1): 4.5mm

[0216] Groove length (L2): 24.3mm

[0217] Slot height: 150mm

[0218] (Mold core (insert))

[0219] Figure 9 The shape of the mold core 80 (insert) used is indicated in the text. Figure 9 (a) is a plan view. Figure 9 (b) is a side view. Figure 9 (c) is the front view. The blackened area in the figure is the region that becomes the pressure-bearing area (surface area S) of the insert.

[0220] The dimensions corresponding to the pressure area of ​​the insert of the mold core 80 (insert) are as follows.

[0221] Blade pressure width (L3): 3.9mm

[0222] Insert compression length (L4): 20.5mm

[0223] Insert pressure height (L5): 156mm

[0224] In addition, Examples 3 to 5 used mold cores 80 with the same shape but different surface conditions.

[0225] <Surface Roughness Ra>

[0226] The surface roughness Ra of the mold core 80 was measured using a measuring device (manufactured by Keyence Corporation) in accordance with JIS B 0601-2001.

[0227] (Pull-out force F and Pull-out force F / Surface area S)

[0228] Prepare the stator simulation model and mold core 80 as described above. After inserting the mold core 80 into the three slots 8, seal it with encapsulating resin. After sealing, perform hydraulic extraction in the original molded state, and measure the extraction force with a pressure measuring instrument.

[0229] The temperature at the time of extraction is 80℃, and the pressure area (surface area S) of the insert is 70cm². 2 .

[0230] [Table 2]

[0231]

[0232] This application claims priority based on Japanese Patent Application No. 2023-203627, filed on December 1, 2023, the entire contents of which are incorporated herein by reference.

[0233] Explanation of reference numerals in the attached figures

[0234] 100 Motor, 1 Housing, 2 Rotor, 4 Stator, 5 Permanent Magnet, 6 Yoke, 7 Tooth, 8 Slot, 9 Coil, 21 Coil Reception, 41 Stator Core, 50 Resin Layer, 51 Inner Tooth Surface Resin Layer, 52 Outer Tooth Surface Resin Layer, 53 Inner Yoke Surface Resin Layer, 62, 72 Inner Wall Surface, 65 Resin Encapsulation, 80 Mold Core (Insertion).

Claims

1. A thermosetting resin composition for filling the space formed between a mold core insert and the wall of a slot inserted into a stator to form an insulating layer, the thermosetting resin composition being characterized in that it comprises: Epoxy resin; Curing agent; Inorganic filler materials; and wax, The wax contains higher fatty acid esters or higher fatty acid amides, wherein the amount of the higher fatty acid esters or higher fatty acid amides is less than 1.0% by mass relative to the total thermosetting resin composition.

2. A method for manufacturing a stator, characterized in that: An insulating layer is formed on the wall of the tank using the thermosetting resin composition of claim 1. The method for manufacturing the stator includes: In the core configuration step, a insert-shaped mold core is inserted into the groove, forming a filling space between the groove wall and the mold core for filling the thermosetting resin composition; and The resin filling process involves filling the filling space with the thermosetting resin composition.

3. The method for manufacturing a stator according to claim 2, characterized in that: The surface roughness Ra of the mold core is less than 10 μm.

4. The method for manufacturing a stator according to claim 2 or 3, characterized in that: The surface of the mold core has a coating.

5. The method for manufacturing a stator according to claim 2 or 3, characterized in that: The process following the resin filling process includes a mold core removal process, which involves extracting and removing the mold core.

6. The method for manufacturing a stator according to claim 5, characterized in that: In the mold core removal process, the extraction force F when removing the mold core is less than 250 kgf.

7. The method for manufacturing a stator according to claim 6, characterized in that: In the mold core removal process, the ratio of the surface area S of the mold core to the extraction force F, F / S, is 3.6 kgf / cm². 2 the following.

8. The method for manufacturing a stator according to claim 5, characterized in that: The mold core removal process is performed in the original molded state.

9. The method for manufacturing a stator according to claim 2 or 3, characterized in that: The cured thermosetting resin composition has a glass transition temperature (Tg) of 120°C or higher.

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