Stator manufacturing method and mold
By using an expandable elastic core to adhere closely to the stator core's irregular surfaces, resin burrs are prevented, ensuring effective insulation and sealing of coils in stator manufacturing.
Patent Information
- Authority / Receiving Office
- JP Β· JP
- Patent Type
- Applications
- Current Assignee / Owner
- SUMITOMO BAKELITE CO LTD
- Filing Date
- 2024-12-10
- Publication Date
- 2026-06-22
Smart Images
Figure 2026100948000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for manufacturing a stator and a mold used in such a manufacturing method.
Background Art
[0002] In a rotating electric machine such as a motor or a generator, when a coil is accommodated in a slot provided in a stator, a technique of filling a resin material into the slot to ensure insulation between the slot and the coil is known (see, for example, Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] By the way, resin burrs or the like may occur in the coated resin on the inner diameter side surface of the stator core, that is, on the shaft center side surface of the tooth portion. This is because the stator core is obtained by laminating and tightly fixing a plurality of electromagnetic steel sheets in the axial direction. For example, it occurs due to dimensional accuracy variations caused by the stacking thickness of the electromagnetic steel sheets. As a result, when the stator core is coated with resin, the dimensional accuracy variations of the electromagnetic steel sheets become apparent, and so-called resin burrs occur in the coated resin.
[0005] [[ID= The present invention has been made in view of such a situation, and an object thereof is to provide a technique for preventing resin burrs from occurring on the inner diameter side surface of the stator core, that is, on the shaft center side surface of the tooth portion when the stator core is resin-coated.
Means for Solving the Problems
[0006] According to the present invention, the following techniques are provided. 1. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core, which is hollow inside and expands when liquid is introduced into the cavity, in the opening of the stator body. A first core deformation step involves introducing a liquid into the first core to expand it and causing the first core to adhere closely to the end face on the central side of the teeth portion, A first resin molding step involves introducing a first resin material into the mold and covering at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics. 2. The method for manufacturing a stator according to 1, wherein the first core is elastically deformed. 3. The method for manufacturing a stator according to 1. or 2., wherein the liquid is oil. 4. The first core deformation step makes the internal pressure of the first core greater than the injection pressure of the first resin composition in the first resin molding step. A method for manufacturing a stator as described in any one of 1 to 3. 5. A method for manufacturing a stator according to any one of claims 1 to 4, wherein at least the surface of the first core has at least one of ethylene propylene diene rubber or fluororesin rubber. 6. A method for manufacturing a stator according to any one of claims 1 to 5, further comprising a second core placement step of placing a second core in a slot, which is a space formed between the teeth, prior to the first core deformation step. 7. In the subsequent steps following the first resin molding step, A third core placement step involves placing the coil in the slot between adjacent teeth of the stator body, then placing the stator body and the coil inside the mold, and placing a deformable third core in the opening of the stator body. A third core deformation step involves deforming the third core to bring it into close contact with the end face on the central side of the teeth portion, A coil sealing step involves introducing a second resin material into the slot in which the coil is arranged to seal the coil, A method for manufacturing a stator according to any one of 1 to 6, comprising the above. 8. The method for manufacturing a stator according to 7, wherein the third core is the same core as the first core. 9. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core made of an elastic material in the opening of the stator body, A first core deformation step involves applying a compressive force in the thickness direction to the portion of the first core located outside the thickness-direction end of the stator body, causing the circumferential surface of the elastic body to protrude toward the teeth portion and to bring it into close contact with the end face on the central side of the teeth portion. A first resin molding step involves introducing a first resin material into the mold and covering at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics. 10. A mold used in a method for manufacturing a stator, comprising coating a stator body, which has an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, with a resin composition, A mold body having an internal space for housing the stator body, The core placed in the opening of the stator body, and having, The core is a mold having a cavity inside with an elastic member, and expands when liquid is introduced into the cavity. 11. A mold used in a method for manufacturing a stator, which coats a stator body having an annular yoke portion formed by laminating electromagnetic steel sheets and having an opening at the center, and a plurality of teeth portions extending toward the center of the yoke portion with a resin composition, A mold body having an internal space for accommodating the stator body, The core placed in the opening of the stator body, A pressing portion that deforms the core so that when the core is placed in the opening of the stator body, a portion of the core inside the opening of the stator body adheres to the end face on the center side of the teeth portion by applying a force to the core. having, a mold.
Advantages of the Invention
[0007] According to the present invention, when resin coating is performed on the stator core, it is possible to provide a technique for preventing resin burrs from occurring on the surface on the inner diameter side of the stator core, that is, the surface on the axial center side of the teeth portion.
Brief Description of the Drawings
[0008] [Figure 1] It is a cross-sectional view in a direction perpendicular to the rotation axis direction of the motor according to the first embodiment. [Figure 2] It is a cross-sectional view in the rotation axis direction of the motor according to the first embodiment. [Figure 3] It is a view of the stator showing an enlarged region X of FIG. 1 according to the first embodiment. [Figure 4] It is a view of the first embodiment excluding the coil and the second resin layer from FIG. 3. [Figure 5] It is a flowchart showing a method for manufacturing a stator according to the first embodiment. [Figure 6]This is a cross-sectional view perpendicular to the axial direction of the stator and mold (first core, second core) in the primary molding process according to the first embodiment. [Figure 7] This is a cross-sectional view parallel to the axial direction of the stator and mold (first core, second core) in the primary molding process according to the first embodiment. [Figure 8] This is an enlarged view of region X1 in Figure 6 according to the first embodiment. [Figure 9] This is a cross-sectional view perpendicular to the axial direction of the stator and mold (first core) in the secondary molding process according to the first embodiment. [Figure 10] This is a cross-sectional view parallel to the axial direction of the stator and mold (first core) in the secondary molding process according to the first embodiment. [Figure 11] This is an enlarged view of region X2 in Figure 9 according to the first embodiment. [Figure 12] This figure illustrates the state of the first core before and after deformation according to the second embodiment. [Modes for carrying out the invention]
[0009] <First Embodiment> <Overview> In this embodiment, an example of application to an electric motor (motor) as a rotating electric machine (motor, generator, or motor / generator combined machine) will be described. Figure 1 schematically shows a cross-sectional view of the motor 100 in a direction perpendicular to the rotation axis direction. Figure 2 schematically shows a cross-sectional view of the motor 100 in the direction of the rotation axis direction.
[0010] The outline of this embodiment is as follows. In the motor 100, the walls of the slot 8 of the stator 4 (tooth wall 72, yoke wall 62) are covered with a resin layer 50 (first resin layer 50a). Also, the coil 9 in the slot 8 is sealed with a resin layer 50 (second resin layer 50b). When forming the resin layers 50 (first resin layer 50a and second resin layer 50b), a core (first core 110) is placed in the central opening of the stator core 41 (hereinafter referred to as "core opening 45") so as to close the central opening of the slot 8 (between the tips 71 of adjacent tooth portions 7). As will be described in detail later, the first core 110 is expanded toward the stator core 41 so as to bring the first core 110 into contact with the central surface of the stator core 41 (i.e., the surface of the tip portion of the tooth portion 7; hereinafter referred to as "tip surface 75"). In particular, the stator core 41 is constructed by laminating multiple electromagnetic steel sheets in the axial direction and fixing them in close contact. At this time, the surface formed by the lamination of the electromagnetic steel sheets (for example, the tip surface 75 of the tooth portion 7) will have irregularities due to the lamination of the electromagnetic steel sheets, and the irregularities during lamination may become larger due to the tolerances of each electromagnetic steel sheet. As a result, when a general metal core is used, a gap is likely to occur between the core and the opening surface of the stator core 41 (the tip surface on the center side of the tooth portion 7), and there is a risk that resin may leak into that gap. Therefore, the core, which was conventionally made of metal, is replaced with a core made of a material whose surface is elastically deformable, and furthermore, by deforming it hydraulically, the stator core 41 (tooth portion 7) and the first core 110 are brought into close contact, and the irregularities caused by the lamination of the electromagnetic steel sheets are filled in. The details will be explained below.
[0011] <Basic structure of motor 100> The motor 100 comprises a case 1, and a rotor 2, a stator 4, and a coil 9 housed inside the case 1.
[0012] <Case 1> Case 1 is constructed having a cylindrical portion 1a and side plate portions 1b and 1c that close off both axial ends of the cylindrical portion 1a. For the material of Case 1, for example, an aluminum alloy (cast product), a resin material, or a combination thereof can be used.
[0013] <Rotor 2> The rotor 2 is housed inside the case 1. A rotating shaft 3 is mounted at the center of the rotor 2 as the output shaft. Both ends of the rotating shaft 3 are supported by side plates 1b and 1c via bearings 3a, respectively. This allows the rotor 2 to rotate freely around the rotating shaft 3.
[0014] The rotor 2 has permanent magnets 5 built into it. Specifically, as shown in Figure 1, multiple (eight in this case) permanent magnets 5 are arranged at equal intervals on the same circumference. At this time, the magnetic poles of adjacent permanent magnets 5 are set to be opposite to each other.
[0015] A cylindrical stator 4 is positioned and fixed on the inner circumference of the cylindrical portion 1a, surrounding the outer circumference of the rotor 2. A small gap (air gap) is provided between the inner surface of the stator 4 and the outer surface of the rotor 2.
[0016] <Status 4> See also Figures 3 and 4. Figure 3 is a diagram of the stator 4, showing an enlarged view of region X in Figure 1. Figure 4 is a diagram of Figure 3 with the coil 9 and the second resin layer 50b (also called the resin sealing portion) removed. The stator 4 has a stator core 41 and a coil 9 resin-sealed in a slot 8.
[0017] The stator core 41 is formed by laminating and tightly fixing multiple electromagnetic steel sheets in the axial direction. As shown in Figure 1, when viewed from the axial end, the stator core 41 has an annular yoke portion 6 and multiple tooth portions 7 extending from the yoke portion 6 toward the rotor 2 side (inner circumference side). The multiple tooth portions 7 are arranged at equal intervals in the circumferential direction. The space between adjacent tooth portions 7 is a slot 8. In addition, the tooth portions 7 are covered with a thin first resin layer 50a formed by encircling the resin composition. The axial length of the stator 4 is, for example, 100 mm to 300 mm. A motor 100 having a stator 4 of this size is suitable, for example, as a drive motor for an electric vehicle.
[0018] <Coil 9> The coil 9 is, for example, a U-shaped flat wire, and is wound so as to be housed in two spaced-apart slots 8 that straddle the teeth portion 7. The coil 9 is sealed in the slots 8 by a resin layer 50 (second resin layer 50b). The coil 9 comprises a coil body made of a good conductor such as copper with a rectangular cross-section, and a resin coating layer covering its surface. The resin coating layer can be made of the same material as described for the resin layer 50 (first resin layer 50a, second resin layer 50b). The material for the resin layer 50 will be described later.
[0019] <Teeth section 7> The teeth section 7 is provided in correspondence with the permanent magnet 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to the attraction and repulsion with the corresponding permanent magnet 5.
[0020] The teeth portion 7 has a larger circumferential width on the outer circumference side and a smaller width on the inner circumference side, tapering towards the inner circumference. On both sides of the inner end face of the teeth portion 7 (hereinafter referred to as the "tip face 75"), tooth tip portions 71 are formed that extend opposite to each other along the circumferential direction to reduce the width of the slot 8. A thin first resin layer 50a is provided on the teeth portion 7.
[0021] <Slot 8> Slot 8 is the space between adjacent tooth portions 7, and is provided such that, for example, the tooth wall surfaces 72 of opposing tooth portions 7 along the radial direction are parallel. The space between the tips 71 of the tooth portions forms an inner circumferential opening of slot 8. Slot 8 includes a plurality of coils 9 arranged on the outer circumferential side (yoke portion 6 side) and a second resin layer 50b that seals the coils 9.
[0022] <Resin layer 50> For example, as shown in Figure 3, the resin layer 50 has a first resin layer 50a and a second resin layer 50b. The first resin layer 50a is formed on the periphery of the teeth portion 7 by a primary molding process described later. The second resin layer 50b seals the coil 9 housed in the slot 8 by a secondary molding process described later. Hereafter, if the first resin layer 50a and the second resin layer 50b are not distinguished, they will be referred to as "resin layer 50".
[0023] <First resin layer 50a> More specifically, the first resin layer 50a integrally surrounds the periphery of the teeth portion 7 with the resin composition and includes a teeth inner surface resin layer 51 that covers the inner wall surface of the teeth portion 7 (hereinafter referred to as "teeth wall surface 72"), a teeth outer surface resin layer 52 that covers the upper surface 75a and the lower surface of the teeth portion 7, and a yoke inner surface resin layer 53 that covers the inner wall surface of the yoke portion 6 (yoke wall surface 62).
[0024] The first resin layer 50a is formed by insert molding to cover the teeth portion 7 in a thin, circumferential manner, thereby tightly fixing the multiple laminated electromagnetic steel sheets in the stator 4, more specifically in the teeth portion 7. Note that the resin layer 50 does not necessarily need to be formed in a thin, circumferential manner around the teeth portion 7; for example, the outer tooth resin layer 52 may be omitted. The presence of the inner tooth resin layer 51 and the inner yoke resin layer 53 ensures insulation between the coil 9 and the inner wall surfaces of the slots 8 (the tooth wall surface 72 of the teeth portion 7 and the yoke wall surface 62 of the yoke portion 6). The manufacturing method of the first resin layer 50a will be described in detail later in the manufacturing method section, referring to Figures 5 to 11.
[0025] The thickness of the inner surface resin layer 51 of the teeth is 100 ΞΌm or more and 400 ΞΌm or less. The lower limit of the thickness is preferably 150 ΞΌm or more, and more preferably 200 ΞΌm or more. The upper limit of the thickness is preferably 350 ΞΌm or less, and more preferably 300 ΞΌm or less.
[0026] The lower limit of the thickness is preferably within the above range, from the viewpoint of ensuring the fluidity of the resin composition in the extremely narrow space between the mold core (second core 120) and the tooth portion 7 (tooth wall surface 72) with respect to the stator axis length (i.e., the thickness of the stator 4) during insert molding.
[0027] In a structure in which the coil 9 is wound around the teeth portion 7 and placed in the slot 8, it is preferable to set the upper limit of the thickness within the above range from the viewpoint of improving the efficiency of space utilization within the slot 8 and ensuring the freedom of the usable coil 9 size and performance such as magnetic flux density.
[0028] The thickness of the yoke inner surface resin layer 53 may be the same as the thickness range of the tooth inner surface resin layer 51, or it may be a different value. The thickness of the tooth outer surface resin layer 52 is not particularly limited, but it may be about the same as the tooth inner surface resin layer 51.
[0029] As will be described later, there is a surface on the second core 120 used when forming the first resin layer 50a that has a draft angle. In the portion in contact with the surface with the draft angle, the thickness of the resin layer 50 (tooth inner surface resin layer 51) will be the thickness that reflects the draft angle. For example, as shown in Figure 6, the lower side (bottom surface 75b side) of the tooth inner surface resin layer 51 is thicker, and the upper side (top surface 75a side) is thinner.
[0030] <Second resin layer 50b (resin sealing part)> The second resin layer 50b seals the coil 9 placed in the slot 8 after the first resin layer 50a has been formed on the teeth portion 7. The second resin layer 50b is provided by insert molding. The resin material used for the second resin layer 50b can be the same as that described later for the first resin layer 50a. The manufacturing method for the second resin layer 50b will be described in detail in the manufacturing method described later with reference to Figures 5 to 11.
[0031] <Physical properties of resin layer 50> The physical properties of the cured resin material constituting the resin layer 50 are as follows, for example. The resin materials of the first resin layer 50a and the second resin layer 50b may be the same or different. In either case, the first resin layer 50a and the second resin layer 50b have the physical properties and composition described below.
[0032] The thermal conductivity of the cured resin material is 0.5 W / (mΒ·K) or higher. The lower limit of the thermal conductivity is preferably 1.0 W / (mΒ·K) or higher, and more preferably 2 W / (mΒ·K) or higher. The upper limit of the thermal conductivity is not particularly limited, but a practical value is 10 W / (mΒ·K).
[0033] The glass transition temperature Tg of the resin composition of the resin layer 50 is 120Β°C or higher, preferably 140Β°C or higher, and more preferably 160Β°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 coil 9 becomes more resistant to heat generation, allowing it to be used at high output. The resin composition of the resin layer 50 is described in detail below.
[0034] <Material (composition) of resin layer 50> The resin composition of the resin layer 50 preferably includes a thermosetting resin (A), a filler (B), and a curing agent (C).
[0035] [Thermosetting resin (A)] Examples of thermosetting resins (A) include epoxy resins, cyanate resins, polyimide resins, benzoxazine resins, unsaturated polyester resins, phenolic resins, melamine resins, silicone resins, bismaleimide resins, phenoxy resins, and acrylic resins. One of these may be used alone as thermosetting resin (A), or two or more may be used in combination. In particular, from the viewpoint of having high insulating properties, epoxy resin and phenolic resin are preferred as the thermosetting resin (A). From the viewpoint of ensuring flow in extremely narrow areas during molding, epoxy resin is especially preferred.
[0036] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene)bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene)bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexydiene bisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol group methane type novolac type epoxy resin, and tetraphenol group ethanol. Examples include novolac epoxy resins such as n-type novolac epoxy resins and novolac epoxy resins having a condensed ring aromatic hydrocarbon structure; biphenyl epoxy resins; arylalkylene epoxy resins such as xylylene epoxy resins and biphenyl aralkyl epoxy resins; naphthalene epoxy resins such as naphthylene ether epoxy resins, naphthol epoxy resins, naphthalenediol epoxy resins, bifunctional or tetrafunctional epoxy naphthalene resins, binaphthyl epoxy resins, and naphthalene aralkyl epoxy resins; anthracene epoxy resins; phenoxy epoxy resins; dicyclopentadiene epoxy resins; norbornene epoxy resins; adamantane epoxy resins; and fluorene epoxy resins. One of these may be used alone, or two or more may be used in combination.
[0037] Among epoxy resins, it is preferable to use one or more selected from the group consisting of bisphenol-type epoxy resins, novolac-type epoxy resins, biphenyl-type epoxy resins, arylalkylene-type epoxy resins, naphthalene-type epoxy resins, anthracene-type epoxy resins, and dicyclopentadiene-type epoxy resins, from the viewpoint of further improving heat resistance and insulation reliability.
[0038] Examples of phenolic resins include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, and bisphenol A novolac resin, as well as resol-type phenolic resins. One of these may be used alone, or two or more may be used in combination. Among phenolic resins, phenol novolac resins are preferred.
[0039] The content of thermosetting resin (A) is preferably 1% by mass or more, and more preferably 5% by mass or more, relative to the total amount of resin composition in 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 resin composition in the resin layer 50. When the content of thermosetting resin (A) is above the lower limit, the handling properties of the entire resin composition of the resin layer 50 are improved, making it easier to form the inner surface resin layer 51 of the teeth, and improving the strength of the inner surface resin layer 51 of the teeth. If the content of thermosetting resin (A) is below the above upper limit, the coefficient of linear expansion and elastic modulus of the inner surface resin layer 51 of the teeth will be further improved, and the thermal conductivity will be further improved.
[0040] [Filler (B)] In this embodiment, the filler (B) is used from the viewpoint of improving the thermal conductivity of the resin layer 50 (more specifically, the inner surface resin layer 51 of the teeth) and obtaining strength.
[0041] As the filler (B), an inorganic filler is preferred, and a thermally conductive filler is particularly preferred. More specifically, as the filler (B), from the viewpoint of balancing thermal conductivity and electrical insulation, examples include silica, alumina, boron nitride, aluminum nitride, and silicon carbide. These may be used individually or in combination of two or more. Among these, the filler (B) is preferably alumina or boron nitride.
[0042] The content of filler (B), that is, the content of the above-mentioned filler, is preferably 60% by mass or more of the total amount of the resin composition.
[0043] [Hardening agent (C)] When using an epoxy resin or a phenolic resin as the thermosetting resin (A) in the resin composition, it is preferable to further include a curing agent (C).
[0044] As the curing agent (C), one or more selected from curing catalysts (C-1) and phenolic curing agents (C-2) can be used. Examples of curing catalysts (C-1) include organometallic salts such as zinc naphthenate, cobalt naphthenate, tin octate, cobalt octate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); tertiary amines such as triethylamine, tributylamine, and 1,4-diazabicyclo[2.2.2]octane; and 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2,4-diethylimidazole, and 2-phenyl-4-methyl-5-hydroxyimidazole. Examples include imidazoles such as dazole and 2-phenyl-4,5-dihydroxymethylimidazole; organophosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium-tetraphenylborate, triphenylphosphine-triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenol compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and p-toluenesulfonic acid; and mixtures thereof. As the curing catalyst (C-1), one type, including its derivatives, can be used alone, or two or more types, including their derivatives, can be used in combination. The content of the curing catalyst (C-1) is not particularly limited, but it is preferably 0.001% by mass or more and 1% by mass or less, relative to the total amount of the resin composition.
[0045] Furthermore, examples of phenolic curing agents (C-2) include novolac-type phenolic resins such as phenol novolac resin, cresol novolac resin, trisphenolmethane-type novolac resin, naphthol novolac resin, and aminotriazine novolac resin; modified phenolic resins such as terpene-modified phenolic resin and dicyclopentadiene-modified phenolic resin; aralkyl-type resins such as phenol aralkyl resin having a phenylene skeleton and / or biphenylene skeleton, and naphthol aralkyl resin having a phenylene skeleton and / or biphenylene skeleton; bisphenol compounds such as bisphenol A and bisphenol F; and resol-type phenolic resins. These may be used individually or in combination of two or more types. Among these, from the viewpoint of improving the glass transition temperature and reducing the coefficient of linear expansion, the phenolic curing agent (C-2) is preferably a novolac-type phenolic resin or a resol-type phenolic resin.
[0046] 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, based on the total amount of the resin composition. On the other hand, the content is preferably 30% by mass or less, and more preferably 15% by mass or less, based on the total amount of the resin composition.
[0047] [Coupling agent (D)] The resin composition may also contain a coupling agent (D). The coupling agent (D) can improve the wettability of the interface between the thermosetting resin (A) and the filler (B).
[0048] The coupling agent (D) is not particularly limited, but it is preferable to use one or more coupling agents selected from, for example, epoxy silane coupling agents, cationic silane coupling agents, amino silane coupling agents, titanate-based coupling agents, and silicone oil-type coupling agents. The content of the coupling agent (D) is not particularly limited, but is preferably 0.05% by mass or more, and more preferably 0.1% by mass or more, based on 100% by mass of the filler (B). On the other hand, the content is preferably 3% by mass or less, and more preferably 2% by mass or less, based on 100% by mass of the filler (B).
[0049] [Phenoxy resin (E)] Furthermore, the resin composition may also contain phenoxy resin (E). By including phenoxy resin (E), the flexibility 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.
[0050] Furthermore, the inclusion of phenoxy resin (E) increases viscosity, reducing fluidity and suppressing the formation of voids. Additionally, when the resin layer 50 is used in close contact with a metal component (i.e., the teeth portion 7), the adhesion between the metal and the cured resin composition can be improved.
[0051] Examples of phenoxy resins (E) include phenoxy resins having a bisphenol skeleton. Examples include phenoxy resins having a lipid, naphthalene skeleton, anthracene skeleton, and biphenyl skeleton. Furthermore, phenoxy resins with structures possessing multiple of these skeletons can also be used.
[0052] The content of phenoxy resin (E) is preferably, for example, 3% by mass or more and 10% by mass or less, based on the total amount of the resin composition.
[0053] [Release agent] The resin composition preferably contains a release agent. This improves the release properties after molding. Examples of release agents include natural waxes such as carnauba wax, synthetic waxes such as montanic acid ester wax and polyethylene oxide wax, higher fatty acids such as zinc stearate and their metal salts, and paraffin. These may be used individually or in combination of two or more.
[0054] When a release agent is used, its content is preferably 0.01 to 3% by mass, more preferably 0.05 to 2% by mass, of the total resin molding material. This ensures that the effect of improving release properties is reliably obtained. As a result, the molding accuracy of the inner surface resin layer 51 of the teeth of the resin layer 50 (first resin layer 50a) can be increased.
[0055] [Other ingredients] The resin composition may also contain antioxidants, leveling agents, and the like, as long as they do not impair the effects of the present invention.
[0056] <Method for manufacturing Stator 4> The manufacturing method of the stator 4 in this embodiment will be described with reference to Figures 5 to 11. Figure 5 is a flowchart illustrating the manufacturing method of the stator 4. Figures 6 to 8 illustrate the primary molding process. Figure 6 is a cross-sectional view perpendicular to the axial direction of the stator 4 and the mold (first core 110, second core 120) in the primary molding process. Figure 7 is a cross-sectional view parallel to the axial direction of the stator 4 and the mold (first core 110, second core 120) in the primary molding process. Figure 8 is an enlarged view of region X1 in Figure 6. Figures 9 to 11 illustrate the secondary molding process. Figure 9 is a cross-sectional view of the stator 4 and mold (first core 110) perpendicular to the axial direction during the secondary molding process. Figure 10 is a cross-sectional view of the stator 4 and mold (first core 110) parallel to the axial direction during the secondary molding process. Figure 11 is an enlarged view of region X2 in Figure 9.
[0057] The following describes the manufacturing method of the stator 4, focusing mainly on the process of coating the stator core 41 (stator body) with a resin layer 50, followed by a description of the mold 90 (particularly the first core 110 and the second core 120) used in the manufacturing method.
[0058] As shown in the flowchart of Figure 5, the manufacturing method of the stator 4 includes a stator placement step S10, a primary molding step S10, and a secondary molding step S20. The primary molding step S10 is a step of covering the teeth portion 7 with a first resin layer 50a. The secondary molding step S20 is a step of sealing the coil 9 in the slot 8 with a second resin layer 50b. In the primary molding step S10 and the secondary molding step S20, the first core 110 placed in the core opening 45 expands toward the stator core 41 side (tooth portion 7 side) by introducing liquid into the internal cavity. The liquid is oil.
[0059] <Primary forming process S10> The primary molding process S10 includes a stator placement process (A) S11, a first core placement process (A) S12, a second core placement process S13, a first core deformation process (A) S14, and a first resin molding process S15.
[0060] The stator placement process (A)S11 is the process of placing the stator core 41 in the mold 90 (lower mold 91a).
[0061] The first core placement step (A)S12 is the step of placing the first core 110 in the core opening 45 of the stator core 41. The first core 110 has a hollow interior and expands when a liquid (more specifically, oil) is introduced into the cavity.
[0062] The first core 110 is provided in a substantially cylindrical shape, as shown in Figures 6 to 8, for example, and has a bladder 111, a pressure accumulation section 112, and a liquid flow path 113.
[0063] The bladder 111 is an elastically deformable member provided on the outer surface (surface) of a cylindrical shape and is expandable outward (in the direction of the stator core 41). The pressure accumulation section 112 is a space into which oil is introduced to expand the bladder 111. The liquid flow path 113 is a path through which oil is introduced into the pressure accumulation section 112 from the outside.
[0064] The pressure accumulator 112 has the inner circumferential surface of the bladder 111 as part of its wall surface, allowing high-pressure oil to be introduced inside and causing the bladder 111 to expand.
[0065] The material for the bladder 111 is selected considering the type of mineral oil used to generate hydraulic pressure during rubber expansion. For example, nitrile rubber (NBR) and fluororubber (FKM) can be used, with fluororubber being particularly preferred from the viewpoint of high heat resistance and oil resistance. Such a material allows for close contact with the tip surface 75 of the stator core 41 (tooth portion 7) when expanded. That is, even if the tip surface 75 of the stator core 41 (tooth portion 7) has irregularities, the bladder 111 can absorb and cover those irregularities. Furthermore, it can exhibit high resistance to high-pressure oil. In other words, it can achieve oil resistance and strength to withstand high pressure. For example, in the primary molding process S10 and the secondary molding process S20, the molding pressure may be around 8.0 to 12.0 MPa and the molding temperature around 150Β°C to 180Β°C. The above-mentioned material is suitable as a material that can withstand such conditions. Furthermore, the thickness of the bladder 111 is, for example, between 10 mm and 20 mm. If the thickness of the bladder 111 is within this range, it can be expanded by hydraulic pressure while ensuring sufficient strength, and it can absorb irregularities on the tip surface 75 resulting from the lamination of the electromagnetic steel sheets constituting the stator core 41. It can also continuously withstand the molding pressure and molding temperature mentioned above. Regarding the irregularities on the tip surface 75 resulting from the lamination of the electromagnetic steel sheets, the difference between the most protruding part and the most recessed part is between 0.3 mm and 1.0 mm. The upper limit of the irregularities is preferably 0.8 mm or less, and more preferably 0.5 mm or less. By using the first core 110 having the bladder 111, the tolerance range for irregularities on the tip surface 75 can be widened from the viewpoint of the manufacturing process (mold) for forming the resin layer 50.
[0066] The second core placement step S13 is the step of placing the second core 120, which is used to coat the teeth portion 7 with the first resin layer 50a, into the slot 8. The order of the first core placement step (A) S12 and the second core placement step S13 may be reversed, as long as they are performed before the first core deformation step S22.
[0067] The second core 120 is, for example, blade-shaped. The cross-sectional shape of the second core 120 is approximately rectangular, as shown in Figure 8, for example, and a protrusion 123 is formed on the core opening 45 side (bladder 111 side). The protrusion 123 protrudes slightly from between the tips 71 of the teeth towards the bladder 111. The width of the protrusion 123 is exactly the same as the distance between the tips 71 of the teeth, and the surfaces 122 on both sides of the protrusion 123 abut against the inner circumferential surfaces of the tips 71 of the teeth. As a result, a space for providing the first resin layer 50a is formed in the slot 8, and the area on the core opening 45 (bladder 111) side is closed. Since the bladder 111 is elastically deformable, it is not necessary to form a recess in the bladder 111 that matches the protrusion 123. Once the first core 110 and the second core 120 are in place, the upper mold 92a is attached to the upper end of the stator core 41. The upper mold 92a is provided with gates 95 for introducing the material of the first resin layer 50a into the slots 8.
[0068] The first core deformation step S14 is a step in which the first core 110 (i.e., the bladder 111) is expanded by introducing a liquid (oil) into the first core 110, causing the first core 110 to adhere closely to the tip surface 75 of the tooth portion 7. Figure 8 shows the state in which the bladder 111 is in close contact with the tip surface 75 of the tooth portion 7. The pressure of the introduced oil (hydraulic pressure), i.e., the pressure in the pressure accumulator 112, is greater than the pressure at which the material for the first resin layer 50a (first resin composition) is injected (injection pressure). As mentioned above, if the molding pressure is 8.0 to 12.0 MPa, the hydraulic pressure is set to exceed that value.
[0069] The first resin molding process S15 is a process of introducing the material for the first resin layer 50a (first resin material) to coat at least a part of the stator 4, in this case the teeth portion 7, with the first resin layer 50a. When the first resin molding process S23 is completed, the stator 4, which is coated with the first resin layer 50a, is temporarily removed from the mold 90 (lower mold 91a, upper mold 92a, first core 110, second core 120). As described above, the elastically deformable bladder 111 seals the irregularities on the tip surface 75 of the teeth portion 7, allowing the first core 110 and the stator core 41 (teeth portion 7) to be tightly fitted together without any gaps. As a result, when the resin material for forming the first resin layer 50a is injected into the slot 8, it is possible to prevent the resin material from leaking out of the slot 8 into the core opening 45. If it leaks out towards the core opening 45, a resin layer (also called a resin burr) that should not be formed will be provided on the inner circumferential surface of the stator core 41, but in this embodiment, such a resin layer is not formed. In particular, the stator core 41 is made by laminating and tightly fixing multiple electromagnetic steel sheets in the axial direction. At this time, the surface formed by the lamination of the electromagnetic steel sheets (for example, the tip surface 75 of the teeth portion 7) will have irregularities due to the lamination of the electromagnetic steel sheets, and the irregularities during lamination may become larger due to the tolerances of each electromagnetic steel sheet. As a result, when a general metal core is used, a gap tends to form between the core and the opening surface of the stator core 41 (the central end surface of the teeth portion 7), and resin leaks into this gap. However, in the first core 110, by making the part that contacts the stator core 41 (teeth portion 7) an elastically deformable material, the irregularities caused by the lamination of the electromagnetic steel sheets can be filled.
[0070] <Secondary molding S20> The secondary molding process S20 will be explained with reference to Figures 9 to 11. Secondary molding S20 is performed in a later process than primary molding S10 (first resin molding process S15). The secondary molding process S20 includes a stator placement process (B) S21, a first core placement process (B) S22, a coil placement process S23, a first core deformation process (B) S24, and a second resin molding process S25.
[0071] The stator placement process (B)S21 is the process of placing the stator core 41, in which the teeth portion 7 is coated with a first resin layer 50a in the primary molding process S10, into the mold 90 (lower mold 91b). In the secondary molding S20, a portion of the coil 9 to be placed in the slot 8 extends outward beyond the upper and lower ends of the stator core 41. Therefore, the lower mold 91b and the upper mold 92b are provided with coil housing portions 93 and 94 to accommodate the coil 9 located on the outside.
[0072] The first core placement step (B)S22 is a step in which the first core 110 is placed in the core opening 45 of the stator core 41, similar to the first core placement step (A)S12 of the primary molding step S10. The first core 110 used in the primary molding step S10 and the core used in the secondary molding step S20 may be the same, or a different core (third core) with a similar structure may be used. Below, an example using the same first core 110 as in the primary molding step S10 will be described.
[0073] The coil placement process S23 is the process of placing the coil 9 into the slot 8.
[0074] The first core deformation step (B)S24 is a step in which, similar to the first core deformation step (A)S14 of the primary molding step S10, liquid (oil) is introduced into the first core 110 to expand the first core 110 (i.e., the bladder 111) and bring the first core 110 into close contact with the tip surface 75 of the teeth portion 7. The pressure of the introduced oil (hydraulic pressure), i.e., the pressure of the pressure accumulator 112, is greater than the pressure (injection pressure) at which the material (second resin composition) is injected to provide the second resin layer 50b.
[0075] The second resin molding step S25 is a coil sealing step in which a second resin material is introduced into the slot 8 where the coil 9 is placed, and the coil 9 is sealed with a second resin layer 50b. At this time, similar to the first resin molding step S15 of the primary molding step S10, the slot 8 is sealed at the opening on the core opening 45 side (the space between the tips 71 of the teeth) by the bladder 111, so that the second resin material introduced into the slot 8 does not leak out. In addition, by making the part of the bladder 111 that contacts the stator core 41 (teeth 7) an elastically deformable member, the unevenness caused by the lamination of the electromagnetic steel sheets can be filled in.
[0076] As described above, the mold 90 used in the primary molding process S10 and the secondary molding process S20 coats a stator core 41 (stator body), which is formed by laminating electromagnetic steel sheets and has an annular yoke portion 6 with an opening in the center and a plurality of teeth portions 7 extending toward the center of the yoke portion 6, with a resin composition (first resin layer 50a, second resin layer 50b). The mold 90 has a mold body (lower mold 91a, 91b, upper mold 92a, 92b) having an internal space for housing the stator core 41, and a first core 110 positioned in the core opening 45 of the stator core 41. The first core 110 is an elastic member with a cavity inside, and expands when liquid is introduced into the cavity.
[0077] <Second Embodiment> The second embodiment will be described with reference to Figure 12. In the following, Figure 12 will mainly be described in terms of the differences from the first embodiment, and similar points will be omitted from the explanation as appropriate.
[0078] In this embodiment, the difference from the first embodiment lies in the first core 210 placed in the core opening 45. Therefore, the primary molding process S10 and the secondary molding process S20 of the first embodiment are carried out similarly.
[0079] The first core 210 in this embodiment is cylindrical and made of an elastically deformable material. Figure 12(a) shows the state before deformation. By applying force to both ends of the cylindrical shape, the pressurizing section 96 deforms the first core 210 by compressing it in the height direction of the cylinder, causing the circumferential surface to expand (protrude) toward the stator core 41, as shown in Figure 12(b). In Figure 12(b), the first core 210 before deformation is shown by a dashed line. As a result, in the primary molding process S10 and the secondary molding process S20, the expanded circumferential surface of the first core 210 comes into close contact with the inner circumferential surface of the stator core 41 (the tip surface 75 of the tooth tip 71), similar to the first embodiment. The pressurizing section 96 can have any configuration as long as it can adequately compress the first core 210.
[0080] The mold 90 of this embodiment has the same mold configuration as the first embodiment, and the mold 90 comprises a mold body (lower mold 91a, upper mold 92a) having an internal space for housing the stator core 41, and a first core 210 positioned in the core opening 45 of the stator core 41. The first core 210 has a pressurizing portion 96 that, when force is applied to the first core 210 while it is positioned in the core opening 45, deforms so that the portion of the first core 210 inside the core opening 45 comes into close contact with the tip surface 75 of the teeth portion 7. This embodiment also achieves the same effects as the first embodiment.
[0081] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted.
[0082] <Summary of Embodiments> The features of this embodiment can be summarized as follows: 1. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core, which is hollow inside and expands when liquid is introduced into the cavity, in the opening of the stator body. A first core deformation step involves introducing a liquid into the first core to expand it and causing the first core to adhere closely to the end face on the central side of the teeth portion, A first resin molding step involves introducing a first resin material into the mold and covering at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics. 2. The method for manufacturing a stator according to 1, wherein the first core is elastically deformed. 3. The method for manufacturing a stator according to 1. or 2., wherein the liquid is oil. 4. The first core deformation step makes the internal pressure of the first core greater than the injection pressure of the first resin composition in the first resin molding step. A method for manufacturing a stator as described in any one of 1 to 3. 5. A method for manufacturing a stator according to any one of claims 1 to 4, wherein at least the surface of the first core has at least one of ethylene propylene diene rubber or fluororesin rubber. 6. A method for manufacturing a stator according to any one of claims 1 to 5, further comprising a second core placement step of placing a second core in a slot, which is a space formed between the teeth, prior to the first core deformation step. 7. In the subsequent steps following the first resin molding step, A third core placement step involves placing the coil in the slot between adjacent teeth of the stator body, then placing the stator body and the coil inside the mold, and placing a deformable third core in the opening of the stator body. A third core deformation step involves deforming the third core to bring it into close contact with the end face on the central side of the teeth portion, A coil sealing step involves introducing a second resin material into the slot in which the coil is arranged to seal the coil, A method for manufacturing a stator according to any one of 1 to 6, comprising the above. 8. The method for manufacturing a stator according to 7, wherein the third core is the same core as the first core. 9. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core made of an elastic material in the opening of the stator body, A first core deformation step involves applying a compressive force in the thickness direction to the portion of the first core located outside the thickness-direction end of the stator body, causing the circumferential surface of the elastic body to protrude toward the teeth portion and to bring it into close contact with the end face on the central side of the teeth portion. A first resin molding step involves introducing a first resin material into the mold and covering at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics. 10. A mold used in a method for manufacturing a stator, comprising coating a stator body, which has an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, with a resin composition, A mold body having an internal space for housing the stator body, A core placed in the opening of the stator body, It has, The aforementioned core is an elastic material with a cavity inside, which expands when a liquid is introduced into the cavity, in a mold. 11. A mold used in a method for manufacturing a stator, comprising coating a stator body, which has an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, with a resin composition, A mold body having an internal space for housing the stator body, A core placed in the opening of the stator body, When the core is positioned in the opening of the stator body, a pressurizing unit is provided to deform the core by applying force to it so that the portion of the core located inside the opening of the stator body is in close contact with the end face on the center side of the teeth portion. A mold having [Explanation of symbols]
[0083] 4 stata 6. York section 7 Teeth section 8 slots 9 coils 41 Stator Core 45 Core opening 71. Tip of the tooth section 75 Tip surface 110 First core 111 Bladder 112 Pressure Accumulator 113 Liquid channel 120 Second core 210 First core
Claims
1. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core, which is hollow inside and expands when liquid is introduced into the cavity, in the opening of the stator body. A first core deformation step involves introducing a liquid into the first core to expand it and bring the first core into close contact with the end face on the central side of the teeth portion, A first resin molding step involves introducing a first resin material into the mold and coating at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics.
2. The method for manufacturing a stator according to claim 1, wherein the first core is elastically deformed.
3. The method for manufacturing a stator according to claim 1 or 2, wherein the liquid is oil.
4. The first core deformation step makes the internal pressure of the first core greater than the injection pressure of the first resin composition in the first resin molding step. A method for manufacturing a stator according to claim 1 or 2.
5. The method for manufacturing a stator according to claim 1 or 2, wherein at least the surface of the first core has at least one of ethylene propylene diene rubber or fluororesin rubber.
6. A method for manufacturing a stator according to claim 1 or 2, further comprising a second core placement step of placing a second core in a slot, which is a space formed between the teeth, prior to the first core deformation step.
7. In the subsequent steps following the first resin molding step, A third core placement step involves placing the coil in the slot between adjacent teeth of the stator body, then placing the stator body and the coil inside the mold, and placing a deformable third core in the opening of the stator body. A third core deformation step involves deforming the third core to bring it into close contact with the end face on the central side of the teeth portion, A coil sealing step involves introducing a second resin material into the slot in which the coil is arranged to seal the coil, A method for manufacturing a stator according to claim 1 or 2, comprising having
8. The method for manufacturing a stator according to claim 7, wherein the third core is the same core as the first core.
9. A method for manufacturing a stator, comprising coating a stator body with a resin composition, the stator body having an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, A stator placement step involves placing the stator body into the cavity of the mold, A first core placement step involves placing a first core made of an elastic material in the opening of the stator body, A first core deformation step involves applying a compressive force in the thickness direction to the portion of the first core located outside the thickness-direction end of the stator body, causing the circumferential surface of the elastic body to protrude toward the teeth portion and to bring it into close contact with the end face on the central side of the teeth portion. A first resin molding step involves introducing a first resin material into the mold and coating at least a portion of the stator body with the first resin composition, A method for manufacturing a stator, comprising the same characteristics.
10. A mold used in a method for manufacturing a stator, comprising coating a stator body, which has an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, with a resin composition, A mold body having an internal space for housing the stator body, A core placed in the opening of the stator body, It has, The aforementioned core is an elastic material with a cavity inside, which expands when a liquid is introduced into the cavity, in a mold.
11. A mold used in a method for manufacturing a stator, comprising coating a stator body, which has an annular yoke portion with an opening in the center and a plurality of teeth portions extending toward the center of the yoke portion, formed by laminating electromagnetic steel sheets, with a resin composition, A mold body having an internal space for housing the stator body, A core placed in the opening of the stator body, When the core is positioned in the opening of the stator body, a pressurizing unit is provided to deform the core by applying force to it so that the portion of the core located inside the opening of the stator body is in close contact with the end face on the center side of the teeth portion. A mold having