Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K15/00—Processes or apparatus specially adapted for manufacturing, assembling, maintaining or repairing of dynamo-electric machines
  • H02K15/12—Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines
  • H02K15/121—Impregnating, moulding insulation, heating or drying of windings, stators, rotors or machines of cores

Definitions

• the present invention relates to a method for manufacturing a stator.
• Patent Document 1 discloses a technique for forming an insulating layer by injecting and hardening a resin between the coil and the peripheral wall of the slot.
• a thin insulation layer is preferable in order to accurately position the coils while maintaining proper insulation, and to improve the space utilization efficiency of the slots.
• the insulation layer When molding the insulation layer inside the slots, if the pull-out force of the molded parts (called blades or cores) is too great, the insulation layer may be damaged, and a technology to address this was needed.
• the present invention was developed in consideration of these circumstances, and aims to provide a technology that prevents the insulating layer from being damaged when the molded parts are pulled out of the mold when molding the insulating layer inside the slot.
• a method for manufacturing a stator comprising: forming a resin layer on a wall surface of a slot, the resin layer being a space between teeth extending from an annular yoke portion, using a mold; the mold has a blade accommodated inside the slot, and when the blade is accommodated, a space formed between a wall surface of the slot and the blade is filled with a resin material to form the resin layer; A draft angle is set on a surface of the blade facing a wall surface of the slot, The draft angle is 15 ⁇ m or more and 100 ⁇ m or less, The method for manufacturing a stator, wherein the surface on which the draft is set has a surface roughness Ra of 0.2 ⁇ m or more and 2 ⁇ m or less.
• a space formed between a wall surface of the slot and the blade when the blade is accommodated is formed by closing tips of the adjacent teeth portions with a mold member separate from the blade, The method for manufacturing a stator according to (4), wherein the draft angle is set on the surface of the blade facing the mold member.
• the resin layer is a cured product of a resin material, The method for manufacturing a stator according to any one of (1) to (5), wherein the resin material is made of one or two types of thermosetting resin selected from the group consisting of epoxy resin and phenolic resin. (7) The method for manufacturing a stator according to any one of (1) to (6), wherein the resin layer has a thickness of 100 ⁇ m or more and 400 ⁇ m or less.
• the present invention provides a technology that prevents the insulating layer from being damaged when the molded parts are pulled out of the mold when molding the insulating layer inside the slot.
• FIG. 1 is a cross-sectional view of a motor according to an embodiment taken along a direction perpendicular to the rotation axis of the motor; 1 is a vertical cross-sectional view of a motor according to an embodiment of the present invention taken along a rotation axis thereof;
• FIG. 2 is an enlarged view of the periphery of a slot according to the embodiment.
• FIG. 4 is an enlarged view of the periphery of the slot according to the embodiment, showing the coil and resin sealing portion in the slot from FIG. 3 .
• 4 is a cross-sectional view of the periphery of the slot according to the embodiment, taken along line AA in FIG. 3.
• 5 is a cross-sectional view of the periphery of the slot according to the embodiment, taken along line BB of FIG.
• FIG. 4 is a flowchart illustrating a method for manufacturing a stator according to the embodiment.
• 10A to 10C are diagrams illustrating the transition of the state inside the slot during the resin layer forming step in the embodiment.
• 10A to 10C are diagrams illustrating the transition of the state inside the slot during the resin layer forming step in the embodiment.
• FIG. 2 is a diagram showing a blade according to an embodiment.
• FIG. 10 is a diagram illustrating the size of a slot in the embodiment.
• FIG. 1 is a schematic cross-sectional view of the motor 100 taken perpendicular to the rotational axis direction.
• FIG. 2 is a schematic cross-sectional view of the motor 100 taken along the rotational axis direction.
• FIG. 3 is an enlarged view of the slot periphery (area X in FIG. 1 ), showing a cross-sectional view of the portion where the coil 9 protrudes from the end of the slot 8.
• FIG. 4 is a diagram of FIG. 3 , omitting the coil 9 in the slot 8 and the resin sealing portion 65.
• FIG. 5 is a cross-sectional view taken along the line A-A in FIG. 3 .
• FIG. 6 is a cross-sectional view taken along the line B-B in FIG. 4 .
• the resin layer 50 is indicated by black ink for convenience.
• the rotating shaft 3 side of the motor 100 will be referred to as the inner periphery (or rotating shaft side), and the case 1 side will be referred to as the outer periphery.
• the outline of this embodiment is as follows.
• a motor 100 the wall surfaces (tooth wall surfaces 72, yoke wall surfaces 62) of slots 8 of a stator 4 are covered with a resin layer 50 made of an insulating resin composition.
• a draft gradient is set in a mold core (hereinafter, blade 80) and the surface roughness of the blade surface is set, thereby suppressing the pull-out force of the blade 80 and preventing damage to the insulating layer.
• the draft gradient refers to the gradient of the inclined surface on the cross section set for removing the blade 80, and is explained as the horizontal length of the inclined surface when the removal direction is defined as the vertical direction and the horizontal direction is defined relative to that. This will be explained in detail below.
• the motor 100 includes a case 1 , and a rotor 2 , a stator 4 , and a coil 9 housed inside the case 1 .
• the case 1 includes a cylindrical portion 1 a and side plates 1 b and 1 c that close both axial ends of the cylindrical portion 1 a.
• the case 1 can be made of, for example, an aluminum alloy (cast metal), a resin material, or a combination thereof.
• the rotor 2 is housed inside the case 1.
• a rotating shaft 3 is attached to the center of the rotor 2 as an output shaft. Both ends of the rotating shaft 3 are supported by the side plate portions 1b and 1c via bearings 3a. This allows the rotor 2 to rotate freely around the rotating shaft 3.
• Permanent magnets 5 are installed inside the rotor 2. Specifically, as shown in Figure 1, multiple (eight in this case) permanent magnets 5 are arranged at equal intervals on the same circumference. In this case, the magnetic poles of adjacent permanent magnets 5 are arranged so that they are opposite to each other.
• a cylindrical stator 4 is positioned and fixed to the inner periphery of the cylindrical portion 1a, surrounding the outer periphery of the rotor 2.
• a small gap is provided between the inner periphery of the stator 4 and the outer periphery of the rotor 2.
• the stator 4 has a stator core 41 and coils 9 sealed in slots 8 .
• the stator core 41 is formed by stacking a plurality of 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 has an annular yoke portion 6 and a plurality of teeth portions 7 extending from the yoke portion 6 toward the rotor 2 (inner periphery).
• the plurality of teeth portions 7 are arranged at equal intervals in the circumferential direction. In this example, as shown in FIG. 1 , 24 teeth portions 7 are provided. Slots 8 are provided between each tooth portion 7.
• the coil 9 is a U-shaped rectangular wire wound so as to be housed in two spaced apart slots 8 across the teeth 7.
• the coil 9 is housed in a distributed winding manner in a liner member 20 arranged in the slot 8.
• the coil 9 has a coil body made of a good conductor such as copper and having a rectangular cross section, and a resin coating layer covering the surface.
• the resin coating layer can be made of the same material as that of the resin layer 50 described below.
• 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 with the corresponding permanent magnets 5.
• the teeth 7 are tapered, with a larger circumferential width on the outer periphery and a smaller width on the inner periphery. Teeth tips 71 are formed at the inner periphery end of the teeth 7, facing each other along the circumferential direction so as to reduce the width of the slot 8.
• the slots 8 are spaces between adjacent teeth 7, and are provided so that the tooth wall surfaces 72 of the teeth 7 that face each other in the radial direction are parallel to each other.
• the space between the tooth tips 71 forms an opening on the inner circumferential side of the slots 8.
• the slots 8 include a plurality of coils 9 arranged on the outer circumferential side (the yoke portion 6 side) and a resin sealing portion 65 provided on the inner circumferential side (the tooth tip 71 side).
• resin layer 50 is formed by integrally wrapping a resin composition around the periphery of tooth portion 7 to cover it, and includes a teeth inner surface resin layer 51 that covers the inner wall surface (tooth wall surface 72) of tooth portion 7, a teeth outer surface resin layer 52 that covers the upper surface 75a and lower surface 75b of tooth portion 7, and a yoke inner surface resin layer 53 that covers the inner wall surface (yoke wall surface 62) of yoke portion 6.
• the resin layer 50 is inserted into the stator 4, and is thinly wrapped around the teeth 7 to cover them, thereby tightly fixing the multiple laminated electromagnetic steel sheets in the teeth 7. It is not necessary to wrap the resin layer 50 thinly around the teeth 7, and the teeth outer surface resin layer 52 may be omitted.
• the presence of the teeth inner surface resin layer 51 and the yoke inner surface resin layer 53 ensures insulation between the coil 9 and the inner wall surface of the slot 8 (the tooth wall surface 72 of the teeth 7 and the yoke wall surface 62 of the yoke 6).
• the thickness of the tooth inner surface resin layer 51 is 100 ⁇ m or more and 400 ⁇ m or less.
• the lower limit of the thickness is preferably 150 ⁇ m or more, and more preferably 200 ⁇ m or more.
• the upper limit of the thickness is preferably 350 ⁇ m or less, and more preferably 300 ⁇ m or less.
• the lower limit of the thickness is preferably within the above range from the viewpoint of ensuring the fluidity of the resin composition in the extremely narrow portion between the mold (blade 80) and the tooth portion 7 (tooth wall surface 72) relative to the axial length of the stator (i.e., the thickness of the stator 4) during insert molding.
• the upper limit of the thickness within the above range in order to increase the efficiency of space utilization within the slot 8, allow for flexibility in the size of the coil 9 that can be used, and ensure performance such as magnetic flux density.
• the thickness of the yoke inner surface resin layer 53 may be the same as or different from the thickness range of the tooth inner surface resin layer 51.
• the thickness of the tooth outer surface resin layer 52 is not particularly limited, but can be approximately the same as that of the tooth inner surface resin layer 51.
• the surface of the blade 80 used to form the resin layer 50 has a surface on which a draft gradient is provided.
• the thickness of the resin layer 50 (tooth inner surface resin layer 51) reflects the draft gradient.
• the tooth inner surface resin layer 51 is thicker on the lower side (lower surface 75b side) and thinner on the upper side (upper surface 75a side) in the figure.
• the physical properties of the cured resin material that forms the resin layer 50 are, for example, as follows.
• the thermal conductivity of the cured resin material is 0.5 W/(m ⁇ K) or more.
• the lower limit of the thermal conductivity is preferably 1.0 W/(m ⁇ K) or more, and more preferably 2 W/(m ⁇ K) or more.
• the upper limit of the thermal conductivity is not particularly limited, but a practical value is, for example, 10 W/(m ⁇ K).
• 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 within the above range, the motor 100 can be used at high temperatures, and the motor 100 is more resistant to heat generation in the coil 9, allowing it to be used at high output.
• the resin composition of the resin layer 50 will be specifically described below.
• the resin composition of the resin layer 50 preferably contains a thermosetting resin (A), a filler (B), a curing agent (C), and the like.
• thermosetting resin (A) examples include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins.
• the thermosetting resin (A) one of these may be used alone, or two or more may be used in combination.
• epoxy resins and phenolic resins are preferred as the thermosetting resin (A) from the viewpoint of high insulating properties, and epoxy resins are particularly preferred from the viewpoint of ensuring flow in extremely narrow sections during molding.
• epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexidienebisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol methane type novolac type epoxy resin, tetraphenol type epoxy resin, etc.
• bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(
• epoxy resins include novolac-type epoxy resins such as ethane-type novolac-type epoxy resins and novolac-type epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl-type epoxy resins; aryl alkylene-type epoxy resins such as xylylene-type epoxy resins and biphenyl aralkyl-type epoxy resins; naphthalene-type epoxy resins such as naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene diol-type epoxy resins, difunctional to tetrafunctional epoxy naphthalene resins, binaphthyl-type epoxy resins, and naphthalene aralkyl-type epoxy resins; anthracene-type epoxy resins; phenoxy-type epoxy resins; dicyclopentadiene-type epoxy resins; norbornene-type epoxy resins; adamantane-type epoxy resins
• epoxy resins from the viewpoint of further improving heat resistance and insulation reliability, it is preferable to use one or more types selected from the group consisting of bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, aryl alkylene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, and dicyclopentadiene-type epoxy resins.
• phenolic resin examples include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, and resol-type phenolic resins, etc. One of these may be used alone, or two or more may be used in combination. Among the phenolic resins, phenolic novolac resins are preferred.
• the content of the thermosetting resin (A) is preferably 1% by mass or more, and more preferably 5% by mass or more, relative to the total amount of the resin composition of the resin layer 50. On the other hand, the content is preferably 30% by mass or less, and more preferably 20% by mass or less, relative to the total amount of the resin composition of the resin layer 50.
• the content of thermosetting resin (A) is equal to or greater than the above lower limit, the handleability of the entire resin composition of resin layer 50 is improved, making it easier to form teeth inner surface resin layer 51 and improving the strength of teeth inner surface resin layer 51.
• the content of the thermosetting resin (A) is equal to or less than the upper limit, the linear expansion coefficient and elastic modulus of the teeth inner surface resin layer 51 are further improved, and the thermal conductivity is further improved.
• the filler (B) in this embodiment is used from the viewpoint of improving the thermal conductivity of the resin layer 50 (more specifically, the tooth inner surface resin layer 51) and obtaining strength.
• filler (B) inorganic fillers 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 (B) include silica, alumina, boron nitride, aluminum nitride, and silicon carbide. These may be used alone or in combination of two or more. Of these, alumina and boron nitride are particularly preferred as filler (B).
• the content of filler (B), i.e., the content of the above filler, is preferably 60 mass% or more based on the total amount of the resin composition.
• thermosetting resin (A) When an epoxy resin or a phenolic resin is used as the thermosetting resin (A), the resin composition preferably further contains a curing agent (C).
• the curing agent (C) one or more selected from the group consisting of a curing catalyst (C-1) and a phenol-based curing agent (C-2) can be used.
• the curing catalyst (C-1) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octoate, cobalt octoate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole; imidazoles such as 2-phenyl-4,5-dihydroxymethylimidazole; organic phosphorus compounds such as triphen
• the curing catalyst (C-1) one of these, including derivatives thereof, can be used alone, or two or more of these, including derivatives thereof, can be used in combination.
• 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 based on the total amount of the resin composition.
• the phenolic curing agent (C-2) examples include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, trisphenolmethane-type novolac resin, naphthol novolac resin, and aminotriazine novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resins having a phenylene skeleton and/or biphenylene skeleton and naphthol aralkyl resins having a phenylene skeleton and/or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins, and these may be used alone or in combination of two or more.
• the phenolic curing agent (C-2) is preferably
• the content of the phenolic curing agent (C-2) is not particularly limited, but is preferably 1% by mass or more, and 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, and more preferably 15% by mass or less, relative to the total amount of the resin composition.
• the resin composition may contain a coupling agent (D).
• the coupling agent (D) can improve the wettability at the interface between the thermosetting resin (A) and the filler (B).
• the coupling agent (D) is not particularly limited, but it is preferable to use, for example, one or more coupling agents selected from epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate-based coupling agents, and silicone oil-type coupling agents.
• the content of the coupling agent (D) is not particularly limited, but is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, relative to 100% by mass of the filler (B), while the content is preferably 3% by mass or less, more preferably 2% by mass or less, relative to 100% by mass of the filler (B).
• the resin composition may contain a phenoxy resin (E).
• a phenoxy resin (E) By containing the phenoxy resin (E), the bending resistance of the resin layer 50 can be improved, and the elastic modulus can be reduced, thereby improving the stress relaxation force of the resin layer 50.
• phenoxy resin (E) increases viscosity, reducing fluidity and preventing the occurrence of voids, etc. Furthermore, when the resin layer 50 is used in close contact with a metal member (i.e., teeth portion 7), the adhesion between the metal and the cured resin composition can be improved.
• phenoxy resin (E) examples include phenoxy resins having a bisphenol skeleton, phenoxy resins having a naphthalene skeleton, phenoxy resins having an anthracene skeleton, and phenoxy resins having a biphenyl skeleton. Phenoxy resins having a structure containing a plurality of these skeletons can also be used.
• the content of phenoxy resin (E) is preferably, for example, 3% by mass or more and 10% by mass or less relative to the total amount of the resin composition.
• the resin composition preferably contains a mold release agent, which can improve mold releasability after molding.
• mold release agents include natural waxes such as carnauba wax, synthetic waxes such as Montan acid ester wax and oxidized polyethylene wax, higher fatty acids such as zinc stearate and their metal salts, and paraffin. These may be used alone or in combination of two or more.
• a release agent is used, its content in the entire resin molding material is preferably 0.01 to 3 mass %, and more preferably 0.05 to 2 mass %. This ensures improved release properties. As a result, the molding precision of the teeth inner surface resin layer 51 of the resin layer 50 can be improved.
• the resin composition may also contain other additives such as an antioxidant and a leveling agent, provided that the effects of the present invention are not impaired.
• the resin sealing portion 65 is provided on the inner circumferential side of the slot 8 (toward the tooth tip 71).
• the resin sealing portion 65 may be provided by insert molding or may be provided as a separate component.
• the resin material used for the resin sealing portion 65 may be the same as that described for the resin layer 50.
• a stator 4 is prepared by stacking a plurality of electromagnetic steel plates in the axial direction and closely fixing them together (stator preparation step S10).
• the blade 80 is placed in the slot 8, and an insulating resin composition is wrapped around and coated integrally with the periphery of the tooth portion 7 (tooth wall surface 72, upper surface 75a, and lower surface 75b) and the inner wall surface of the yoke portion 6 (yoke wall surface 62) by insert molding, forming a resin layer 50 (resin layer formation process S20). Details of the resin layer formation process S20 will be described later.
• the coils 9 are placed inside the slots 8 provided with the resin layer 50 (coil placement process S30). After all the coils 9 have been placed, the inner peripheral area of the slots 8 is filled with resin material to obtain the resin-sealed portion 65 (coil sealing process S40).
• Figures 8 and 9 show the transition of the state inside the slot 8 during the resin layer forming process S20, with Figure 8 being a cross-sectional view cut along a plane perpendicular to the axis, and Figure 9 being a cross-sectional view of a portion corresponding to the A-A cross section in Figure 3.
• the resin layer formation process S20 includes a core placement process S21, a resin filling process S22, and a mold core removal process S23.
• Figures 8(a) and 9(a) show the state before the blade 80 is inserted.
• the core placement process S21 is a process of inserting the blade-shaped blade 80 into the slot 8.
• the blade 80 is inserted into the slot 8 from the top side as shown in the figure. At this time, the upper and lower ends of the blade 80 protrude from the upper and lower ends of the slot 8.
• the core placement process S21 forms a space 88 between the wall surfaces of the slot 8 (tooth wall surfaces 72 of the tooth portion 7, yoke wall surfaces 62 of the yoke portion 6) and the blade 80 for filling with a thermosetting resin composition. Because the blade 80 has a draft angle, the distance between the inner wall surface of the slot 8 and the blade 80 becomes wider as it approaches the lower surface 75b.
• the resin filling process S22 is a process of filling the space 88 formed by the core placement process S21 with the above-mentioned thermosetting resin composition.
• the mold core removal step S23 is a step that follows the resin filling step S22 and involves pulling out and removing the blade 80. This step is performed in the as-molded state, i.e., without any after-curing. At this time, the temperature of the resin layer 50 is, for example, 100°C.
• a through hole 85 for handling is provided near the upper end 80a of the blade 80. A predetermined jig is attached to this through hole 85, and the blade 80 is pulled out in the upward direction as shown.
• the resin layer 50 is formed on the wall surfaces of the slot 8 (the tooth wall surfaces 72 of the tooth portion 7 and the yoke wall surfaces 62 of the yoke portion 6).
• the blade 80 has a draft angle, which makes it easier to pull out the blade 80. That is, compared to a case where there is no draft angle, the pulling force can be reduced and damage to the resin layer 50 can be suppressed.
• FIG. 80 The blade 80 used in the resin layer forming step S20 will be described.
• the blade 80 is provided in an appropriate shape depending on the shape of the slot 8 and the resin layer 50, but in this embodiment, it has a long, thin blade shape.
• Figure 10(a) is a front view of the blade 80
• Figure 10(b) is a side view
• Figure 10(c) is a plan view.
• the blade 80 has first to fourth blade surfaces 81 to 84 as surfaces accommodated in the slot 8.
• the first blade surface 81 and second blade surface 82 are surfaces facing the tooth wall surface 72 of the tooth portion 7.
• the third blade surface 83 is a surface facing the yoke wall surface 62.
• the fourth blade surface 84 is a surface facing the space between the tooth portion tips 71, and when the space between the tooth portion tips 71 is sealed with a mold member, it is a surface facing the mold member.
• the front end has a through-hole 85 into which a specified jig can be attached to operate the blade 80.
• the distance between the blade 80 and the slot 8 corresponds to the thickness of the resin layer 50.
• the blade 80 has a draft angle, so the distance changes depending on the draft angle.
• draft gradients d1 and d2 are set on the surfaces (first blade surface 81, second blade surface 82, third blade surface 83) that face the wall surfaces (tooth wall surface 72, yoke wall surface 62) of the slot 8.
• the draft gradient d1 is set on the first blade surface 81 and the second blade surface 82 that face the tooth wall surface 72, which has a large area.
• the draft gradient may be set on only either the first blade surface 81 or the second blade surface 82.
• the draft gradient d1 can be set, for example, to 15 ⁇ m or more and 100 ⁇ m or less.
• the lower limit of the draft gradient is preferably 17 ⁇ m or more, more preferably 20 ⁇ m or more.
• the upper limit of the draft gradient is preferably 50 ⁇ m or less, more preferably 40 ⁇ m or less.
• the tooth tip 71 of the adjacent tooth 7 may be closed by a mold member other than the blade 80.
• a draft angle may be set on the surface of the blade 80 facing the mold member (fourth blade surface).
• the area of the blade 80 where the draft angle is set is at least the area that passes through the slot 8 when the blade is pulled out of the slot 8, more specifically, the portion that faces the resin layer 50 when the resin layer 50 is formed. In other words, the portion that protrudes outside the slot 8 when the resin layer 50 is molded does not need to have a draft angle.
• the blade 80 can be made of a general mold steel material, such as SKD-11 (JIS standard).
• the surfaces of the blade 80 are smoothed so that the surface roughness Ra and RSm are within the specified ranges as follows. This prevents distortion or other effects on the resin layer 50 when the blade 80 is pulled out.
• the surface roughness Ra of the blade 80 is 0.2 ⁇ m or more and 2 ⁇ m or less. There is no particular lower limit, as smoother is preferable, and any realistic value above the above value will suffice.
• the upper limit is preferably 2.0 ⁇ m or less, and more preferably 1.5 ⁇ m or less.
• the surface roughness Ra is measured in accordance with JIS B 0601-2001.
• the surface roughness RSm of the blade 80 is 200 ⁇ m or more and 700 ⁇ m or less. There is no particular lower limit, as smoother is preferable, and any realistic value above the above value will suffice.
• the upper limit is preferably 600 ⁇ m or less, and more preferably 500 ⁇ m or less.
• the surface roughness RSm is measured in accordance with JIS B 0601-2001.
• the surfaces of the blade 80 for which the surface roughness Ra and RSm are set as described above are particularly set on the first blade surface 81 and the second blade surface 82, which face the teeth wall surface 72 with a large area, but only one of them may be set.
• the third blade surface 83 and the fourth blade surface, which have a relatively small area, may have surface roughness Ra and RSm that are larger than the above range to a certain extent.
• a method for manufacturing a stator (4) comprising the steps of: forming a resin layer on a wall surface (tooth wall surface (72) and a yoke wall surface (62)) of a slot (8) inside the slot (8), the wall surface being a space between teeth (7) extending from an annular yoke (6);
• the mold has a blade 80 to be accommodated inside the slot 8, and when the blade 80 is accommodated, a resin material is filled into a space formed between a wall surface (tooth wall surface 72, yoke wall surface 62) of the slot 8 and the blade 80, thereby forming the resin layer 50;
• a draft angle is set on the surface facing the wall surface (tooth wall surface 72, yoke wall surface 62) of the slot 8, The draft angle is 15 ⁇ m or more and 100 ⁇ m or less,
• the method for manufacturing a stator 4 wherein the surface on which the draft angle is
• the resin layer 50 is a cured product of a resin material, The method for manufacturing a stator according to any one of (1) to (5), wherein the resin material is made of one or two types of thermosetting resin selected from the group consisting of epoxy resin and phenolic resin.
• thermosetting resin compositions materials of the resin layer 50 used in the evaluation were as follows.
• Inorganic filler Inorganic filler 1: Fused spherical alumina (manufactured by Micron Co., Ltd., average particle size 20 ⁇ m) Inorganic filler 2: fused spherical silica (manufactured by Tokuyama Corporation, average particle size 0.2 ⁇ m) Inorganic filler 3: Fused spherical alumina (manufactured by Admatechs Co., Ltd., average particle size 0.6 ⁇ m)
• Colorant 1 Carbon black
• Coupling material 1 N-phenyl-3-aminopropyltrimethoxysilane
• Coupling material 2 3-mercaptopropyltrimethoxysilane
• Epoxy resin 1 Biphenyl-type epoxy resin (manufactured by Mitsubishi Chemical Corporation, YX4000HK)
• Epoxy resin 2 Triphenolmethane type phenolic resin (manufactured by Mitsubishi Chemical Corporation, YL6677)
• Curing agent 1 Novolac phenol compound (manufactured by Sumitomo Bakelite Co., Ltd.)
• Curing accelerator 1 Tetraphenylphosphonium 4,4'-sulfonyldiphenolate
• Curing accelerator 2 Tetraphenylphosphonium bis(naphthalene-2,3-dioxy)phenylsilicate
• Wax 1 Carnauba wax (manufactured by Air Water Inc.)
• Wax 3 Diethanolamine dimontanic acid ester
• Ion scavenger 1 Hydrometasite (manufactured by Kyowa Chemical Industry Co., Ltd.)
• Troazole compound 1 Triazole compound (manufactured by Shikoku Chemicals Corporation)
• Silicone resin Silicone oil (KR-480, manufactured by Shin-Etsu Chemical Co., Ltd.) Silicone resin: Epoxy polyether modified silicone oil (FZ-3730, manufactured by Toray Dow Corning Co., Ltd.)
• FIG. 11 shows the shape of the slots in the stator simulation mold, with one slot shown here.
• the dimensions of the slots were as follows: Slot width (L1): 4.5 mm Slot length (L2): 24.3 mm Slot height: 150 mm
• FIG. 10(a) is a plan view
• Figure 10(b) is a side view
• Figure 10(c) is a front view.
• the blackened areas in the figure surfaces corresponding to the first blade surface 81 and the second blade surface 82 in the embodiment
• draft gradients were set according to Examples 1 to 4 and Comparative Examples 1 to 4.
• the surface roughness of the areas where the draft gradients were set was set according to Examples 1 to 4 and Comparative Examples 1 to 4.
• the set draft gradients and surface roughnesses Ra and RSm were as shown in Table 2.
• ⁇ Surface roughness Ra, RSm> The surface roughness Ra and RSm of the blade surface were measured using a measuring device (manufactured by Keyence Corporation, model number VR-5000) in accordance with JIS B 0601-2001.
• ⁇ Forming of resin layer> The blade was placed in a slot, and the resin composition obtained by the above preparation was filled into the space between the slot and the blade. The blade was then pulled out in the as-molded state (temperature: 100° C.). The maximum thickness of the resin layer was 300 ⁇ m, and the minimum thickness was set to a thickness obtained by subtracting the set draft angle.

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