Manufacturing method of stator, stator and metal mold

Abstract

To provide a technique which implements secure insulation processing while improving efficiency of the insulation processing of a stator.SOLUTION: The present invention relates to a manufacturing method of a stator 4 which has a stator core 40, a coil 9 stored in a slot 8 and a resin composition covering the coil 9 and in which a coil end 92 protruding from the slot 8 is bonded with the coil end 92 of the other coil 9 stored in the other slot 8. The manufacturing method of the stator includes: a preparation step of preparing a metal mold 20 holding the stator core 40 and at least one coil end 92 of a wire 90 for coils; a coil insertion step of inserting the wire 90 for coils in which the coil end 92 is held by the metal mold 20, into the slot 8 and protruding the other coil end 92 of the wire 90 for coils from the slot 8; a coil other end holding step of holding the other coil end 92; and a coil tension step of applying a tension load to the at least one coil end 92 in a rotation axis direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] In rotating electric machines such as motors and generators, when a coil is accommodated in a slot provided in a stator, a technique is known in which insulating paper or resin material is filled into the slot to ensure insulation between the slot and the coil (see, for example, Patent Document 1). Patent Document 1 discloses a technique for forming an insulating layer by injecting and curing a resin between a conductor (coil) and a peripheral wall of a slot. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6814568 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, in rotating electrical machines such as motors, there has been a demand for technology to improve the manufacturing efficiency of insulation processing for stators and to ensure reliable insulation processing.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a technique for realizing reliable insulation processing while improving the manufacturing efficiency of insulation processing of a stator. [Means for solving the problem]

[0006] According to the present invention, the following techniques are provided. (1) A method for manufacturing a stator having a stator core made of laminated steel plates, a coil housed in a slot of the stator core, and a resin composition coating the coil, the coil end protruding from the slot of the coil being joined to a coil end of another coil housed in another slot, the method comprising the steps of: a preparation step of preparing the stator core and a die that holds at least one coil end of a coil wire used for the coil; a coil insertion process of inserting the coil wire, the coil end of which is held by the die, into the slot and protruding the other coil end of the coil wire from the slot; a coil other end gripping step of gripping the other coil end; a coil tensioning step of applying a tensile load in a rotation axis direction to at least one of the coil ends; A method for manufacturing a stator comprising the steps of: (2) The method for manufacturing a stator according to (1), further comprising a coil joining process of bending the coil end of the coil wire to which a load has been applied in the direction of the rotation axis in the coil tensioning process, and welding it to the coil end of another coil wire. (3) The die has a gripping portion that grips the coil end of the coil wire, The method for manufacturing a stator according to (1) or (2), wherein an elastic member is interposed between the gripping portion and the coil end. (4) The die has a gripping portion that grips the coil end of the coil wire, the gripping portion crushes and grips at least one of the coil end that is gripped when inserted in the coil insertion step and the coil end that is gripped in the coil other end gripping step, The method for manufacturing a stator according to (3), wherein the coil tensioning step applies a tensile load in the direction of the rotation axis while the coil end is crushed. (5) The gripping portion has a coil end accommodating portion that accommodates the coil end, a coil end pressing portion that presses a portion protruding from the coil end accommodating portion; having The method for manufacturing a stator according to (4), wherein, when the gripping portion crushes the coil end, the gripping portion crushes the portion protruding from the coil end accommodating portion. (6) The method for manufacturing a stator according to any one of (3) to (5), wherein the gripping portion has an unevenness in an area that contacts the coil end. (7) The coil end has a recess in a portion that is gripped by the gripping portion (holding jig), The grip portion has a protrusion that fits into the recess, The method for manufacturing a stator according to any one of (3) to (6), wherein when the gripping portion grips the coil end, the convex portion of the gripping portion is fitted into the concave portion of the coil end. (8) The method for manufacturing a stator according to any one of (3) to (7), wherein the holding portion (pressing jig) commonly holds the coil ends of the coil wire housed in the same slot. (9) A resin molding step of filling the slot with a resin composition, The method for manufacturing a stator according to (2), wherein the coil joining step is performed after the resin molding step. (10) The method for manufacturing a stator according to (9), further comprising a coil end sealing step of sealing the coil end with the resin composition that fills the slots. (11) The method for manufacturing a stator according to (9) or (10), wherein a gate opening for injection molding for filling the resin composition in the resin molding step is provided at a position that does not interfere with the gripping portion. (12) The stator core has a plurality of divided cores divided in a circumferential direction, The method for manufacturing a stator according to any one of (9) to (11), further comprising carrying out the steps up to the resin molding step for each of the split cores, connecting the split cores in a circular ring shape in a state in which the coil wire is placed in the slots and the resin composition is filled therein, and then carrying out the coil joining step. (13) A stator manufactured by the method for manufacturing a stator according to any one of (1) to (12). (14) A mold used to accommodate a coil wire in a slot of a stator core and fill the slot with a resin composition, a stator core receiving portion that receives the stator core; a resin injection unit that supplies a resin composition into the slot of the stator core housing portion; a gripping portion that grips a coil end of the coil wire; and a coil tensioning portion that applies a load to the gripping portion to apply a tensile load to the coil wire. Effect of the Invention

[0007] According to the present invention, it is possible to provide a technique for improving the manufacturing efficiency of the insulation process for a stator and achieving reliable insulation process. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a motor according to an embodiment of the present invention taken along a direction perpendicular to the rotation axis direction. [Diagram 2] 1 is a vertical cross-sectional view of a motor according to an embodiment of the present invention taken along a rotation axis thereof; [Diagram 3] FIG. 2 is an enlarged view of the periphery of one slot according to the embodiment. [Figure 4] 11A to 11C are diagrams illustrating a process for sealing a coil in a slot according to an embodiment. [Diagram 5] 11A to 11C are diagrams illustrating a process for sealing a coil in a slot according to an embodiment. [Figure 6]11A to 11C are diagrams illustrating a process of placing a stator in a die according to an embodiment and placing coils in slots. [Figure 7] 7 is a view taken along the X1 arrow in FIG. 6 according to the embodiment. [Figure 8] 11A to 11C are diagrams illustrating a process of placing a stator in a die according to an embodiment and placing coils in slots. [Figure 9] 9 is a view taken along the X2 arrow in FIG. 8 according to the embodiment. [Figure 10] 11A to 11C are diagrams illustrating variations of the gripping portion according to the embodiment. [Figure 11] 5A to 5C are diagrams illustrating a coil bonding step according to the embodiment. [Figure 12] 5A to 5C are diagrams illustrating a coil bonding step according to the embodiment. [Figure 13] 3A and 3B are diagrams illustrating an example of a split core according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Summary> In this embodiment, an example of application to an electric motor (motor) as a rotating electric machine (electric motor, generator, or dual-purpose motor / generator) will be described. FIG. 1 is a schematic cross-sectional view of the motor 100 in a direction perpendicular to the rotation axis direction. FIG. 2 is a schematic cross-sectional view of the motor 100 in the rotation axis direction. FIG. 3 is an enlarged view of the periphery of the slot (area X in FIG. 1), and is a schematic cross-sectional view of a portion where the coil 9 protrudes from the end of the slot 8. FIG. 4 is a view of FIG. 3 with the coil 9 of the slot 8 and the resin sealing portion 65 omitted. In the following description, the rotating shaft 3 side of the motor 100 is the inner periphery side (or rotating shaft side), and the case 1 side is the outer periphery side.

[0010] <Basic structure of motor 100> Motor 100 includes a case 1, and a rotor 2 and a stator 4 housed inside case 1. Stator 4 includes coils 9 inserted into slots 8 of stator core 40 and sealed with resin part 50.

[0011] <Case 1> The case 1 is configured to have a cylindrical portion 1a and side plate portions 1b, 1c that close both axial ends of the cylindrical portion 1a. The case 1 can be made of a material such as an aluminum alloy (cast metal casting), a resin material, or a combination thereof.

[0012] <Rotor 2> 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, 1c via bearings 3a. This allows the rotor 2 to freely rotate around the rotating shaft 3.

[0013] Permanent magnets 5 are installed inside the rotor 2. Specifically, as shown in Fig. 1, a plurality of (eight here) permanent magnets 5 are arranged at equal intervals on the same circumference. At this time, the magnetic poles of adjacent permanent magnets 5 are set to be different from each other.

[0014] A cylindrical stator core 40 is disposed and fixed on the inner peripheral side of the cylindrical portion 1a so as to surround the outer periphery of the rotor 2. A minute gap (air gap) is provided between the inner peripheral surface of the stator core 40 and the outer peripheral surface of the rotor 2.

[0015] <Stator core 40> Stator core 40 is made of laminated steel plates in which a number of electromagnetic steel plates are stacked in the axial direction and fixed in close contact with each other, and when viewed from the axial end as shown in FIG. 1, it is provided with a yoke portion 6 provided in an annular shape and a number of teeth portions 7 extending from yoke portion 6 toward rotor 2 (the inner periphery side). The teeth portions 7 are arranged at equal intervals in the circumferential direction. Here, as shown in FIG. 1, 24 teeth portions 7 are provided. Slots 8 are provided between each of teeth portions 7. In addition, teeth portion 7 is provided with a resin portion 50 that is wrapped around and thinly covered with a resin composition.

[0016] <Coil 9> The coil 9 is obtained by welding and connecting coil ends 92 of straight coil wire 90 sealed with resin in the slots 8. The connection of the coil ends 92 will be described later. In the following explanation, for the sake of convenience, the portion of the coil wire 90 housed in the slot 8 will be referred to as a coil main body 91, and the portion protruding outside the slot 8 will be referred to as a coil end 92. The coil wire 90 is made of a good conductor such as copper, and is configured using a rectangular wire with a rectangular cross section, the surface of which is covered with a thin insulating film.

[0017] <Teeth part 7> The teeth 7 are provided to correspond to the permanent magnets 5 of the rotor 2 described above, and by sequentially exciting each coil 9, the rotor 2 rotates due to attraction and repulsion between the corresponding permanent magnets 5.

[0018] The teeth 7 are tapered so that the circumferential width is large on the outer periphery and small on the inner periphery. Teeth tips 71 are formed at the inner periphery end of the teeth 7, facing each other in the circumferential direction so as to reduce the width of the slot 8.

[0019] <Slot 8> The slots 8 are spaces between adjacent teeth 7, and are provided so that wall surfaces 72 of teeth 7 facing each other in the radial direction are parallel to each other, as shown in Fig. 3 for example. The space between the tips 71 of the teeth forms the inner peripheral opening of the slots 8. The slots 8 are provided with a plurality of coils 9 arranged on the outer peripheral side (the yoke portion 6 side), and with a resin portion 50 that seals the areas of the slots 8 where no coils 9 are provided.

[0020] <Resin part 50> As described above, the resin part 50 includes an intra-slot resin part 58 that seals the coil 9 within the slot 8, a teeth surface resin part 57 that covers part of the upper surface 75a and lower surface 75b of the teeth part 7, and a yoke surface resin part 56 that covers part of the upper surface 65a and lower surface 65b of the yoke part 6. The in-slot resin portion 58, the teeth surface resin portion 57, and the yoke surface resin portion 56 are formed collectively in the process of sealing the coil 9 (coil wire 90).

[0021] The thickness of the in-slot resin portion 58 (here, the distance between the wall surfaces 72, 62, etc. and the coil 9) is, for example, 50 μm or more and 500 μm or less. The lower limit of the thickness is preferably 100 μm or more, and more preferably 150 μm or more. The upper limit of the thickness is preferably 400 μm or less, and more preferably 300 μm or less.

[0022] It is preferable that the lower limit of the thickness be in the above range from the viewpoint of ensuring the fluidity of the resin composition in the extremely narrow portion between the mold and the teeth portion 7 (wall surface 72) relative to the stator axial length (i.e., the thickness of the stator 4) during insert molding. In a structure in which coil 9 is wound around tooth portion 7 and placed in slot 8, it is preferable to set the upper limit of the thickness within the above range from the standpoint of increasing the efficiency of space utilization within slot 8, allowing freedom in the size of coil 9 that can be used, and ensuring performance such as magnetic flux density.

[0023] The thickness of teeth surface resin part 57 and yoke surface resin part 56 is not particularly limited, but is, for example, 1 to 10 mm, and preferably 2 to 5 mm. Teeth surface resin part 57 and yoke surface resin part 56 are adjacent to coil 9, and it is preferable that the thickness and shape thereof are set so that they can appropriately bear load without suffering damage even in a situation where they come into contact with coil 9 and a load is applied thereto during manufacture or operation.

[0024] <Physical properties of resin part 50> The physical properties of the cured resin material constituting the resin portion 50 are as follows, for example. The thermal conductivity of the cured resin material is 0.5 W / mK or more. The lower limit of the thermal conductivity is preferably 1.0 W / mK or more, and more preferably 2 W / mK or more. The upper limit of the thermal conductivity is not particularly limited, but a practical value is 10 W / mK.

[0025] The glass transition temperature Tg of the resin composition of the resin part 50 is not less than 120° C., preferably not less than 140° C., and more preferably not less than 160° C. By setting the glass transition temperature Tg within the above range, the motor 100 can be used under high temperatures, and can also be resistant to heat generation in the coil 9 and used at high output. The resin composition of the resin portion 50 will be specifically described below.

[0026] <Material of the resin part 50> The resin composition of the resin portion 50 preferably contains a thermosetting resin (A), a filler (B), a curing agent (C), and the like.

[0027] [Thermosetting resin (A)] Examples of the thermosetting resin (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. As the thermosetting resin (A), one of these may be used alone, or two or more of them may be used in combination. Among them, from the viewpoint of high insulating properties, epoxy resin, phenol resin, and phenoxy resin are preferable as the thermosetting resin (A), and epoxy resin is particularly preferable from the viewpoint of ensuring flow in extremely narrow parts during molding.

[0028] Examples of epoxy resins include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol M type epoxy resin (4,4'-(1,3-phenylenediisopridiene) bisphenol type epoxy resin), bisphenol P type epoxy resin (4,4'-(1,4-phenylenediisopridiene) bisphenol type epoxy resin), and bisphenol Z type epoxy resin (4,4'-cyclohexydiene bisphenol type epoxy resin); phenol novolac type epoxy resin, cresol novolac type epoxy resin, trisphenol group methane type novolac type epoxy resin, tetraphenol group ethene type epoxy resin, and the like. Examples of the epoxy resins include novolac-type epoxy resins such as aryl alkylene-type epoxy resins, 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, naphthylene ether-type epoxy resins, naphthol-type epoxy resins, naphthalene diol-type epoxy resins, bifunctional to tetrafunctional epoxy-type 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, and fluorene-type epoxy resins. One of these may be used alone, or two or more may be used in combination.

[0029] Among the 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.

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

[0031] The content of the thermosetting resin (A) is preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total amount of the resin composition of the resin part 50. On the other hand, the content is preferably 30% by mass or less, and more preferably 20% by mass or less, based on the total amount of the resin composition of the resin part 50. When the content of the thermosetting resin (A) is equal to or greater than the above lower limit, the handleability of the entire resin composition of the resin part 50 is improved, the inner surface resin layer 51 is easily formed, and the strength of the inner surface resin layer 51 is improved. When the content of the thermosetting resin (A) is equal to or less than the above upper limit, the linear expansion coefficient and elastic modulus of the inner surface resin layer 51 are further improved, and the thermal conductivity is further improved.

[0032] [Filler (B)] The filler (B) in this embodiment is used from the viewpoint of improving the thermal conductivity of the resin portion 50 (more specifically, the inner surface resin layer 51) and obtaining strength.

[0033] As the filler (B), an inorganic filler is preferable, and a thermally conductive filler is particularly preferable. More specifically, as the filler (B), from the viewpoint of achieving a balance between thermal conductivity and electrical insulation, for example, silica, alumina, boron nitride, aluminum nitride, silicon carbide, etc. may be mentioned. These may be used alone or in combination of two or more. Among them, the filler (B) is preferably alumina or boron nitride.

[0034] The content of the filler (B), ie, the content of the above filler, is preferably 60 mass % or more based on the total amount of the resin composition.

[0035] [Hardening agent (C)] When an epoxy resin or a phenol resin is used as the thermosetting resin (A), the resin composition preferably further contains a curing agent (C).

[0036] As the curing agent (C), one or more types selected from the curing catalyst (C-1) and the phenol-based curing agent (C-2) can be used. Examples of the curing catalyst (C-1) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, 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, 2-phenyl-4-methyl-5-hydroxyimidazole, and the like. imidazoles such as 2-phenyl-4,5-dihydroxymethylimidazole; organic phosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, 1,2-bis-(diphenylphosphino)ethane; phenolic compounds such as phenol, bisphenol A, nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, p-toluenesulfonic acid; and the like, or mixtures thereof. As the curing catalyst (C-1), one of these, including its derivatives, can be used alone, or two or more of these, including its derivatives, can be used in combination. The content of the curing catalyst (C-1) is not particularly limited, but is preferably from 0.001% by mass to 1% by mass based on the total amount of the resin composition.

[0037] Examples of the phenol-based curing agent (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 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. Among these, from the viewpoints of increasing the glass transition temperature and decreasing the linear expansion coefficient, the phenol-based curing agent (C-2) is preferably a novolac-type phenol resin or a resol-type phenol resin.

[0038] The content of the phenol-based curing agent (C-2) is not particularly limited, but is preferably 1% by mass or more, more preferably 5% by mass or more, based on the total amount of the resin composition, while the content is preferably 30% by mass or less, more preferably 15% by mass or less, based on the total amount of the resin composition.

[0039] [Coupling agent (D)] 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).

[0040] The coupling agent (D) is not particularly limited, but it is preferable to use, for example, one or more coupling agents selected from an epoxy silane coupling agent, a cationic silane coupling agent, an amino silane coupling agent, a titanate-based coupling agent, and a silicone oil-type coupling agent. 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, based on 100% by mass of the filler (B), while the content is preferably 3% by mass or less, more preferably 2% by mass or less, based on 100% by mass of the filler (B).

[0041] [Phenoxy resin (E)] Furthermore, the resin composition may contain a phenoxy resin (E). By containing the phenoxy resin (E), the bending resistance of the resin part 50 can be improved, and the elastic modulus can be reduced, so that the stress relaxation force of the resin part 50 can be improved.

[0042] Furthermore, when the phenoxy resin (E) is contained, the viscosity increases, which reduces the fluidity and suppresses the occurrence of voids, etc. Furthermore, when the resin part 50 is used in close contact with a metal member (i.e., the teeth part 7), the adhesion between the metal and the hardened body of the resin composition can be improved.

[0043] The phenoxy resin (E) is, for example, a phenoxy resin having a bisphenol skeleton. Examples of the phenoxy resin include phenoxy resins having a naphthalene skeleton, phenoxy resins having an anthracene skeleton, and phenoxy resins having a biphenyl skeleton. Phenoxy resins having a structure having a plurality of these skeletons can also be used.

[0044] The content of the phenoxy resin (E) is, for example, preferably 3 mass % or more and 10 mass % or less with respect to the total amount of the resin composition.

[0045] [Release agent] The resin composition preferably contains a mold release agent. This can improve the mold releasability after molding. Examples of the mold release agent 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.

[0046] When a mold release agent is used, its content in the entire resin molding material is preferably 0.01 to 3 mass %, more preferably 0.05 to 2 mass %. This can reliably obtain the effect of improving the mold releasability. As a result, the molding precision of the inner resin layer 51 of the resin part 50 can be improved.

[0047] [Other ingredients] The resin composition may further contain an antioxidant, a leveling agent, etc., within the scope of not impairing the effects of the present invention.

[0048] <Manufacturing method of stator 4> The process up to sealing the coil 9 in the slot 8 will be described with reference to the flow charts in Fig. 4 and Fig. 5. Fig. 4 is a view from the end side (rotation shaft direction side) of the stator 4, with Fig. 4(a) showing the stator preparation step S1, Fig. 4(b) showing the coil arrangement step S2, and Fig. 4(c) showing the resin sealing step S3. Fig. 5 is a cross-sectional view of the stator 4, with Fig. 5(a) being the A1-A1 cross-sectional view of Fig. 4(a), Fig. 5(b) being the A2-A2 cross-sectional view of Fig. 4(b), and Fig. 5(c) being the A3-A3 cross-sectional view of Fig. 4(c).

[0049] First, as shown in Figs. 4(a) and 5(a), a stator core 40 made of laminated steel sheets in which a plurality of electromagnetic steel sheets are laminated in the axial direction and tightly fixed is prepared and placed in a die (stator preparation step S1).

[0050] Next, as shown in Figures 4(b) and 5(b), the coil wire 90 is placed in the slot 8 placed in the mold (coil placement step S2). Details will be described in the following Figures 6 and 7, but the coil placement step S2 includes a coil insertion step in which one coil end 92 of the coil wire 90 is gripped and the coil wire 90 is inserted so that the other coil end 92 protrudes from the slot 8, a coil other end gripping step in which the other coil end 92 is gripped, and a coil tensioning step in which at least one coil end 92 is pulled in the direction of the rotation axis to apply tension to the coil wire 90 and straighten it. Through these steps, the stator 4 shown in FIG. 3, FIG. 4(c) and FIG. 5(c) is obtained.

[0051] <Coil placement process and mold> The coil arrangement step S2 (particularly the coil other end gripping step) will be described in detail with reference to Figures 6 and 7. Figure 6 shows the state in which the stator core 40 corresponding to Figure 5 is accommodated in the die 20. Figure 7 shows this state as viewed from the end face side of the stator 4. In Figure 7, the stator core 40 (slots 8, teeth portion 7) is shown with dashed lines in order to focus on the coil wire 90 and the gripping portions (second gripping portions 23a, 23b). The gripping portions are so-called pressing tools for positioning the coil 9.

[0052] Mold 20 is used for injection molding to provide resin portion 50 in stator core 40, and has a stator core accommodating portion 21 that accommodates stator core 40, a resin injection portion that supplies a resin composition to provide resin portion 50 in stator core 40, gripping portions (first gripping portions 22a, 22b and second gripping portions 23a, 23b) that grip coil ends 92 of coil wire 90, and a coil tensioning portion that applies a load to the gripping portions to apply a tensile load to the coil wire.

[0053] The stator core accommodating section 21 has a member corresponding to the outer shape of the stator core 40. For example, when the stator core 40 is divided into one slot as shown in FIG. 6, the stator core 40 has a sector shape when viewed from above (i.e., when viewed from above in the axial direction), so the stator core accommodating section 21 has a member formed in a cylindrical shape into which the sector shape fits. If the stator core 40 has an undivided annular shape, the stator core accommodating section 21 has a member formed in a cylindrical shape into which the annular shape fits. The stator core 40 is accommodated such that the inner circumferential surface 27 of the stator core accommodating section 21 is in close contact with the outer circumferential surface 77 of the stator core 40. The stator core accommodating section 21 has one end (the left end in FIG. 6) as an opening 26 capable of accommodating the stator core 40, and the other end (the right end in FIG. 6) as a bottomed shape with a through hole 28 provided therein.

[0054] With the stator core accommodating portion 21 accommodating the stator core 40 and the coil wire 90 in a state in which they are inserted, the openings at both ends (the opening 26, the through hole 28) are sealed. Specifically, the left opening 26 is sealed by an end die member 22 having a pair of first gripping portions 22a, 22b that grip one coil end 92. The through hole 28 is sealed by an end die member 23 having a pair of second gripping portions 23a, 23b that grip the other coil end 92.

[0055] The first gripping portions 22a, 22b grip one coil end 92 with a predetermined force F1. The second gripping portions 23a, 23b grip the other coil end 92 with a predetermined force F2. The end mold member 23 functions as a coil pulling portion that pulls the second gripping portions 23a, 23b gripping the coil end 92 outward in the axial direction with a predetermined load F3.

[0056] 7 shows a state in which the coil end 92 is held by the holding parts. Here, the second holding parts 23a, 23b are illustrated, but the first holding parts 22a, 22b can be held in the same manner. The pair of second holding parts 23a, 23b commonly hold the coil end 92 of the coil wire 90 housed in the same slot 8. Here, a group of coils of a plurality of (four here) coil wires 90 arranged in a row in a rectangular shape are held by the second holding parts 23a, 23b at the opposing long sides (i.e., both ends in the short direction) of the rectangle with a predetermined load F2. That is, the second holding parts 23a, 23b hold the coil end 92 from the tooth part 7 side. Here, a configuration has been exemplified in which a group of coils of a plurality (four in this case) of coil wire rods 90 are held by a common pair of second gripping portions 23a, 23b, but the present invention is not limited to this configuration, and the second gripping portions 23a, 23b may be configured as a plurality of pairs. For example, the first gripping portions 22a, 22b may be configured as a pair, and the second gripping portions 23a, 23b may be configured as a plurality of pairs. The gripping force for gripping the coil end 92 is set so that the coil end does not shift when a tensile load is applied, but may be, for example, a gripping force that slightly crushes the coil end 92.

[0057] With reference to Fig. 8 and Fig. 9, another example of the coil arrangement step S2 shown in Fig. 6 and Fig. 7 will be described. Fig. 8 shows a state in which the stator core 40 corresponding to Fig. 5 is accommodated in the die 20. Fig. 9 is a view taken along the X2 arrow in Fig. 8, showing a state seen from the end face side of the stator 4. In this example, a coil group of a plurality (four in this case) of coil wire rods 90 is held by the second holding parts 23a, 23b at the opposing short sides (i.e., both ends in the longitudinal direction) of the rectangular coil wire rods 90 with a predetermined load F2. In this example, since the coil ends 92 of adjacent coil wire rods 90 come into contact with each other, insulating paper or the like may be interposed between the coil ends 92.

[0058] The mold 20 is provided with a gate opening (or a resin injection section having a gate opening) for injection molding to fill the resin composition, but this is provided at a position that does not interfere with the gripping sections (first gripping sections 22a, 22b, second gripping sections 23a, 23b). In this embodiment, since the end mold member 23 on the right side in the figure has the function of gripping the coil end 92 as described above and also functions as a coil pulling section, it is preferable that a gate opening be provided in the end mold member 22 on the left side in the figure.

[0059] After all the coil wires 90 are accommodated in the slots 8 and tension is applied to straighten them into a straight line without curves, a resin material is filled into the inside of the slots 8 and into the end faces of the teeth 7 and yoke 6, and insert molding is performed to obtain the resin parts 50 (intra-slot resin parts 58, teeth surface resin parts 57, yoke surface resin parts 56) (resin filling process). By applying a tensile load to the coil wire 90, the positional deviation of the coil wire 90 is eliminated and the bend in the shape of the coil wire 90 is corrected. That is, the distance between the coil wire 90 and the inner wall surface of the slot 8 can be appropriately maintained. More specifically, since the coil wire 90 is neither bent nor displaced, it is possible to prevent the coil wire 90 from contacting the slot 8. In other words, the margin provided for the distance between the coil wire 90 and the inner wall surface of the slot 8 can be reduced. As a result, the occupancy rate of the coil wire 90 that can be accommodated in the slot 8 can be increased, and the output of the motor 100 can be increased, or the size of the motor 100 can be reduced to obtain the same output.

[0060] <Grip Shape> The form of the gripping portion will be described with reference to Fig. 10. Here, a variation of the gripping portion (structure for gripping from the tooth portion 7 side) shown in Fig. 7 will be described. Also, although the second gripping portions 23a and 23b are illustrated, the same structure can be adopted for the first gripping portions 22a and 22b.

[0061] In the example of FIG. 10(a), an elastic member 24 such as rubber is interposed between the second gripping portions 23a, 23b and the coil end 92. The elastic member 24 may be fixed to the second gripping portions 23a, 23b, or may be detachable. It may be provided on only one side of the second gripping portions 23a, 23b, or on both sides, or in the case of both sides, the elastic member 24 may be made of different materials. By providing the elastic member 24, the second gripping portions 23a, 23b can reliably grip the coil end 92. In addition, it is possible to prevent the coil end 92 from being damaged.

[0062] In the example of FIG. 10(b), a groove 25 for arranging the coil end 92 is provided in at least one of the second gripping portions 23a, 23b. Here, the groove 25 is provided in the second gripping portion 23b of the groove 25 on the lower side in the figure. The depth is set, for example, so that when the coil end 92 is accommodated in the groove 25, a part of the coil end 92 slightly protrudes from the groove 25. The part protruding from the groove 25 is used as a crushing allowance when the second gripping portions 23a, 23b grip the coil end 92. With this configuration, the coil end 92 can be securely gripped, and even if the gripping force is too strong, the coil end 92 can be prevented from being excessively crushed.

[0063] 10(c), the area of ​​the second gripping parts 23a, 23b that comes into contact with the coil end 92 (i.e., the gripping surface) is knurled or otherwise processed to form an uneven surface 23c. This allows the gripping surfaces of the second gripping parts 23a, 23b to bite into the coil end 92 or increase friction, making it possible to reliably hold the coil end 92 even when a tensile load is applied.

[0064] In the example of Fig. 10(d), a tensile load is applied to the second gripping portions 23a, 23b and the coil end 92 while they are engaged with each other through a fitting structure. Here, a recess 95 is formed in the coil end 92. The second gripping portions 23a, 23b are provided with protrusions 29 that fit into the recess 95. The protrusions 29 of the second gripping portions 23a, 23b are engaged with the recess 95 of the coil end 92, and a tensile load is applied to the engaged state. This allows a tensile load to be applied to the coil wire 90 without applying a crushing gripping force to the coil end 92.

[0065] <Coil bonding process> The coil joining process will be described with reference to Figures 11 and 12. Figure 11 is a diagram showing the structure of the stator 4 after the resin filling process, with Figure 11(a) being a diagram seen from the end side (axial direction) and Figure 11(b) being a diagram seen from the side. Figure 12 is a schematic diagram of the stator developed in the circumferential direction.

[0066] After obtaining the stator 4 with the resin portion 50 formed by the above-mentioned resin filling process, predetermined coil ends 92 are bent together and bent and welded. This bending and welding of the coil ends 92 is performed for all the coil ends 92 protruding from both axial ends of the slots 8, thereby completing the stator 4 provided with the coils 9. In other words, this process completes the stator 4 in which the coil ends 92 are exposed from the slots 8 and molded within the slots 8. Note that, if necessary, a coil end sealing process may be added in which the coil ends 92 are additionally molded with resin. The resin composition used at this time may be the same as that used when forming the resin portion 50.

[0067] As described above, according to this embodiment, when manufacturing a stator 4 in which coils 9 are resin-sealed within slots 8, by adding a position control technique for the coils 9 (coil wire 90) during molding, a manufacturing method can be realized in which the resin sealing process can be completed in one step while also ensuring insulation.

[0068] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

[0069] <Split core> For example, the stator core 40 can be applied to a configuration having a split core (also called a split stator core) that is divided into a plurality of parts in the circumferential direction. As shown in Fig. 13, the split core 140 is provided with one or more slots 8 depending on the form of division. The example of Fig. 13(a) shows an example of a split core 140 having only one slot 8, and one stator core 40 is formed by connecting 18 split cores 140. The example of Fig. 13(b) shows an example of a split core 140 having nine slots 8, and one stator 4 is formed by connecting two split cores.

[0070] The processes up to the resin molding process are carried out for each split core 140 to obtain split cores 140 with coil wire 90 sealed in slots 8, and then a split core connecting process is carried out to connect a predetermined number of split cores 140, 18 in the example of Figure 13(a) or two in the example of Figure 13(b), into a circular ring shape, and finally a coil joining process is carried out to obtain a stator 4 having a coil 9. [Explanation of symbols]

[0071] 1 case 2 Rotors 3 Rotation Axis 4 Stator 5. Permanent magnets 6. Yoke 7 Teeth 8 Slots 9 Coil 20 Mold 22a, 22b First gripping portion 23a, 23b Second gripping portion 40 Stator core 50 Resin part 56 Yoke surface resin part 57 Teeth surface resin part 58 Resin part inside slot 90 Coil wire 91 Coil body 92 Coil end 140 split core

Claims

1. A method for manufacturing a stator having a stator core made of laminated steel plates, a coil housed in a slot of the stator core, and a resin composition coating the coil, the coil end protruding from the slot of the coil being joined to a coil end of another coil housed in another slot, the method comprising the steps of: a preparation step of preparing the stator core and a die that holds at least one coil end of a coil wire used for the coil; a coil insertion process of inserting the coil wire, the coil end of which is held by the die, into the slot and protruding the other coil end of the coil wire from the slot; a coil other end gripping step of gripping the other coil end; a coil tensioning step of applying a tensile load in a rotation axis direction to at least one of the coil ends; A method for manufacturing a stator comprising the steps of:

2. 2. The method for manufacturing a stator according to claim 1, further comprising a coil joining process of bending a coil end of the coil wire to which a load has been applied in the direction of the rotation axis in the coil tensioning process, and welding the coil end to a coil end of another coil wire.

3. The die has a gripping portion that grips the coil end of the coil wire, The method for manufacturing a stator according to claim 1 , wherein an elastic member is interposed between the gripping portion and the coil end.

4. The die has a gripping portion that grips the coil end of the coil wire, the gripping portion crushes and grips at least one of the coil end that is gripped when inserting in the coil insertion step and the coil end that is gripped in the coil other end gripping step, 3. The method for manufacturing a stator according to claim 1, wherein the coil tensioning step applies a tensile load in the direction of the rotation axis while the coil end is crushed.

5. The gripping portion has a coil end accommodating portion that accommodates the coil end, a coil end pressing portion that presses a portion protruding from the coil end accommodating portion; having The method for manufacturing a stator according to claim 4 , wherein the gripping portion crushes a portion of the coil end protruding from the coil end accommodating portion when crushing the coil end.

6. The method for manufacturing a stator according to claim 4 , wherein the gripping portion has projections and recesses in an area that contacts the coil end.

7. the coil end has a recess in a portion gripped by the gripping portion, The grip portion has a protrusion that fits into the recess, The method for manufacturing a stator according to claim 4 , wherein the protrusions of the gripping portions are fitted into the recesses of the coil ends when the gripping portions grip the coil ends.

8. The method for manufacturing a stator according to claim 4 , wherein the gripping portion commonly grips the coil ends of the coil wires housed in the same slot.

9. A resin molding step of filling the slot with a resin composition, The method for manufacturing a stator according to claim 2 , wherein the coil joining step is performed after the resin molding step.

10. The method for manufacturing a stator according to claim 9 , further comprising a coil end sealing step of sealing the coil end with the resin composition filled in the slot.

11. 10. The method for manufacturing a stator according to claim 9, wherein a gate opening for injection molding for filling the resin composition in the resin molding step is provided at a position not interfering with the gripping portion.

12. The stator core has a plurality of divided cores divided in a circumferential direction, 10. The method for manufacturing a stator according to claim 9, further comprising the steps of: performing the steps up to the resin molding step for each of the split cores; connecting the multiple split cores in a circular ring shape in a state in which the coil wire is placed in the slots and the resin composition is filled therein; and then performing the coil joining step.

13. A stator manufactured by the method for manufacturing a stator according to claim 1 or 2.

14. A mold used to accommodate a coil wire in a slot of a stator core and fill the slot with a resin composition, a stator core receiving portion that receives the stator core; a resin injection unit that supplies a resin composition into the slot of the stator core housing portion; a gripping portion that grips a coil end of the coil wire; and a coil tensioning portion that applies a load to the gripping portion to apply a tensile load to the coil wire.

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