Manufacturing method of stator

Abstract

To provide a manufacturing method of a stator, capable of suppressing variation of a product height and a resin leakage without requiring high-dimension accuracy at manufacturing of a component.SOLUTION: A manufacturing method of a stator of the present disclosure comprises: a step of providing a stator assembly in order to manufacture a stator of which a shaft direction length is set to a predetermined dimension; a step of distributing an annular-shaped resin member of which at least one part is crushed to an outer periphery of the stator assembly when it is pressed to a metal mold having an upper metal mold and a lower metal mold; a step of nipping the stator assembly in which the resin member is distributed between the upper metal mold and the lower metal mold in a state where the resin member is pressed, in which a dimension between the upper metal mold and the lower metal mold when the stator assembly in which the resin member is distributed is nipped is adjusted to a predetermined dimension of the stator to be manufactured; and a step of implanting a mold resin into the metal mold.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a stator. [Background technology]

[0002] A stator constituting a rotating electric machine, for example an induction motor, is resin-molded (resin-sealed) for heat dissipation and insulation (see, for example, Patent Document 1 below). When performing the resin molding, the resin molding is generally performed by placing a stator assembly including a stator core around which a coil is wound and a case that covers the outer periphery of the stator core in a mold, and injecting an insulating resin composition (hereinafter referred to as "molding resin") into the inside while pressing the mold against both axial ends of the stator assembly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 60-002044 Summary of the Invention [Problem to be solved by the invention]

[0004] When resin molding is performed using the above-mentioned method, any gap between the mold and the case can cause resin leakage when the molding resin is injected. In addition, since the mold is pressed against the case, the product height of the stator assembly depends on the dimensions of the case. Considering these factors, high dimensional accuracy is required when manufacturing the case, without even the slightest warping or waviness.

[0005] In view of the above-mentioned problems, the present disclosure aims to provide a stator manufacturing method that can suppress variations in product height and resin leakage without requiring high dimensional accuracy when manufacturing parts. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a manufacturing method of a stator according to a first aspect of the present disclosure is a manufacturing method of a stator having an axial length set to a predetermined dimension, and includes the steps of: providing a stator assembly including a stator core having a coil wound around a plurality of teeth protruding from a yoke; arranging an annular resin member around the outer periphery of the stator assembly, at least a portion of which is crushed when pressed against a mold, the mold including an upper mold arranged at one axial end side of the stator assembly and a lower mold arranged at the other axial end side of the stator assembly; clamping the stator assembly with the resin member arranged between the upper mold and the lower mold in a pressed state, the dimension between the upper mold and the lower mold when the stator assembly with the resin member arranged is clamped is adjusted to the predetermined dimension; and injecting molding resin into the mold.

[0007] In the above-described method of manufacturing a stator, the resin member is crushed and then clamped by a metal mold before the molding resin is injected into the appropriate places of the stator assembly, so that no gap is generated between the metal mold and the resin member, and the injected molding resin does not leak out of the metal mold. Also, since the resin member is crushed, the dimensions of the stator assembly after the molding resin is injected can be adjusted to the desired product dimensions simply by forming the metal mold to match the desired product dimensions, and variation in product dimensions can be suppressed.

[0008] A method for manufacturing a stator according to a second aspect of the present disclosure is the same as the method for manufacturing a stator according to the first aspect of the present disclosure, wherein the resin member is made of a thermoplastic resin, and further includes a step of preheating at least a portion of the mold including the portion that abuts against the resin member.

[0009] In the above-described method for manufacturing a stator, the simple method of bringing a preheated die into contact with the resin member makes it possible to soften the crushed portion and crush it stably.

[0010] A method for manufacturing a stator according to a third aspect of the present disclosure is a method for manufacturing a stator according to the first or second aspect of the present disclosure, wherein the resin member includes a first annular protrusion on at least one of a surface abutting the upper mold and a surface abutting the lower mold.

[0011] In the above-described method of manufacturing a stator, the contact portion between the resin member and the die can be reliably made liquid-tight, and resin leakage can be more reliably prevented.

[0012] A method for manufacturing a stator according to a fourth aspect of the present disclosure is a method for manufacturing a stator according to any of the first to third aspects of the present disclosure, which includes a second annular protrusion on a surface of at least one of the upper mold and the lower mold that abuts against the resin member.

[0013] In the above-described method of manufacturing a stator, the contact portion between the resin member and the die can be reliably made liquid-tight, and resin leakage can be more reliably prevented.

[0014] A method for manufacturing a stator according to a fifth aspect of the present disclosure is a method for manufacturing a stator according to any of the first to fourth aspects of the present disclosure, wherein the stator assembly further includes a case surrounding an outer periphery of the stator core, and the step of arranging the resin member comprises arranging the resin member around the outer periphery of the case.

[0015] In the above-described method for manufacturing a stator, the provision of the case makes it possible to firmly protect the outer periphery of the stator core.

[0016] A sixth aspect of the present disclosure relates to a method for manufacturing a stator according to any one of the first to fifth aspects of the present disclosure, wherein the inner surface of the resin member includes a plurality of protrusions extending inward and having tip ends abutting the outer surface of the stator assembly.

[0017] In the above-described method for manufacturing a stator, by providing a protrusion on the resin member, a gap can be secured between the resin member and the stator assembly into which the molding resin can flow, thereby preventing poor filling of the molding resin.

[0018] A seventh aspect of the present disclosure relates to a method for manufacturing a stator according to any one of the first to sixth aspects of the present disclosure, wherein the resin member is a cylindrical member having an axial length longer than the axial length of the stator core.

[0019] In the above-described method for manufacturing a stator, the stator assembly including the stator core can be protected from external forces and the like by the resin member. Effect of the Invention

[0020] According to the method for manufacturing a stator disclosed herein, it is possible to suppress variations in product height and resin leakage without requiring high dimensional accuracy during component manufacturing. [Brief description of the drawings]

[0021] [Figure 1] 1 is a perspective view showing an example of a stator assembly used in a manufacturing method of a stator according to a first embodiment of the present disclosure. [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 1 is a schematic cross-sectional view showing an example of an apparatus for performing a manufacturing method of a stator according to a first embodiment of the present disclosure. [Figure 4] 5 is a flowchart showing an example of a method for manufacturing a stator according to the first embodiment of the present disclosure. [Diagram 5] FIG. 4 is an enlarged view of part B in FIG. [Figure 6] 3 is a cross-sectional view showing a state after resin molding is performed on the stator assembly shown in FIG. 2. [Figure 7] 6 is an enlarged view corresponding to FIG. 5 and showing a modified example of the resin member and the mold. [Figure 8] 11 is a schematic cross-sectional view showing an example of an apparatus for performing a manufacturing method of a stator according to a second embodiment of the present disclosure. FIG. [Figure 9] 9 is a plan view of the resin member shown in FIG. 8. [Figure 10] 11 is a cross-sectional view showing a stator after a stator assembly has been resin-molded by a manufacturing method for a stator according to a second embodiment of the present disclosure. FIG. [Figure 11] 13 is a schematic cross-sectional view showing an example of an apparatus for performing a manufacturing method of a stator according to a third embodiment of the present disclosure. FIG. [Figure 12] 13 is a cross-sectional view showing a stator after a stator assembly has been resin-molded by a manufacturing method for a stator according to a third embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, each embodiment for carrying out the present disclosure will be described with reference to the drawings. Note that, below, the scope necessary for the explanation to achieve the object of the present disclosure is shown in a schematic manner, and the scope necessary for the explanation of the relevant part of the present disclosure will be mainly explained, and the parts for which explanation is omitted will be based on publicly known technology. In addition, when a plurality of mutually identical or corresponding components are included in the drawing, only some of them may be given reference numerals in order to make the drawing easier to see.

[0023] <First embodiment> FIG. 1 is a perspective view showing an example of a stator assembly used in the manufacturing method of a stator according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view taken along line AA in FIG. The manufacturing method of a stator according to the present embodiment may perform resin molding on a part of a stator assembly 1 constituting a part of an inner rotor type motor as shown in FIG. 1. As shown in FIGS. 1 and 2, this stator assembly 1 includes at least a stator core 2 and a coil 3. The stator assembly 1 may be a part of a motor other than the inner rotor type motor, such as an axial type motor. The inner rotor type motor described above may be, for example, a three-phase motor.

[0024] The stator core 2 may be configured by stacking a plurality of iron core pieces (core pieces) made of electromagnetic steel sheets. The stator core 2 may be configured as an annular member having a central axis X, and may include a yoke 5 formed in an annular, for example cylindrical, shape, and a plurality of teeth 6 (24 in FIG. 1) protruding inward from the inner peripheral surface of the yoke 5. The plurality of teeth 6 are formed in a line substantially at equal intervals in the circumferential direction of the stator core 2, and a slot 7 may be formed between each of the adjacent teeth 6. Note that the number of poles and the number of slots of the stator assembly 1 shown in FIG. 1 are merely examples, and are not limited thereto. The extending direction of the central axis X may also be simply referred to as the "axial direction" hereinafter.

[0025] The coil 3 may be wound in a spiral shape around the teeth 6. An insulator 8 may be interposed between each coil 3 and each tooth 6. The coil 3 may be configured such that a wire made of, for example, copper, aluminum, silver, or an alloy thereof is covered with an insulating coating such as enamel. Although a round wire is illustrated as an example of the wire in FIG. 1, it may also be a rectangular wire, a hexagonal wire, or the like. The coil 3 may include the same number of coils for three phases (specifically, U-phase, V-phase, and W-phase).

[0026] 1 is wound around the teeth 6 so as to have a generally long rectangular shape with the axial direction of the stator core 2 as viewed from the radial direction of the stator core 2. A coil end 3A constituting an end of the coil 3 may be drawn out of the slot 7 (e.g., upward) from one end in the axial direction of the slot 7. In the present embodiment, the coil 3 is exemplified as being formed by winding one electric wire, but the number of electric wires wound may be multiple. Also, instead of the above-mentioned insulator 8, other insulating members, for example, insulating paper or varnish, may be used.

[0027] The stator assembly 1 may also include a case 4 surrounding the outer periphery of the stator core 2. For the case 4, a highly rigid material, for example, a metal plate having a predetermined thickness, may be used, or other materials such as resin may also be used. The outer shape of the case 4 may be a complete cylinder having no bottom at both axial ends, a bottomed cylinder having a bottom at one axial end, or the like. The case 4 exemplified in this embodiment may be a bottomed cylinder whose inner diameter is set to match the outer diameter of the stator core 2. In addition, a support protrusion 4A (see FIG. 3) that forms a bottom on the inner peripheral surface of the case 4 may be formed inside the case 4 in order to support the stator core 2 in a housed state. Furthermore, the axial length of the case 4 may be set to be shorter than the axial length of the stator to be manufactured.

[0028] Furthermore, the stator assembly 1 may include a busbar unit 9 for electrically connecting the coils 3. The busbar unit 9 may be composed of a busbar 10 and a busbar support member 11. The busbar 10 may have one end 10A electrically connected to the coil end 3A extending outside the slot 7, and the other end 10B opposite to the one end 10A may extend outside the stator assembly 1. The busbar support member 11 may be composed of a resin molded into an annular shape according to the shape of the yoke 5, and may be arranged to cover one end of the stator core 2 in the axial direction. At least a part of the middle part of the busbar 10 may be routed inside the busbar support member 11. Therefore, the busbar 10 and the busbar support member 11 may be formed integrally. In the present embodiment, a plurality of busbars 10 may be arranged in a substantially arc shape according to the phase of the coils 3.

[0029] An annular resin member 15 is disposed around the outer periphery of the stator assembly 1 having the above-described configuration. As shown in FIG. 1 and FIG. 2, the resin member 15 can be configured as an annular member coaxial with the stator assembly 1 so as to cover a part of the outer periphery of the stator assembly 1, more specifically, the case 4. The axial length of the resin member 15 in this embodiment is adjusted to be shorter than the axial length of the stator core 2. An approximately flat upper surface 15A that comes into contact with an upper die 21 described later can be formed above the resin member 15, and an approximately flat lower surface 15B that comes into contact with a lower die 22 described later can be formed below the resin member 15. In this embodiment, both the upper surface 15A and the lower surface 15B have an approximately flat shape, but the present disclosure is not limited thereto, and the surfaces do not have to be flat as long as they can maintain a liquid-tight state when they come into contact with the upper die 21 and the lower die 22.

[0030] In the present embodiment, the resin member 15 has an inner surface that has the same shape as the outer peripheral surface of the case 4, and the entire circumference of the inner surface abuts against the outer peripheral surface of the case 4, but is not limited thereto. Specifically, as long as the resin member 15 has a structure that allows it to be supported by the case 4, the shape of the inner surface of the resin member 15 or the outer peripheral surface of the case 4 may be changed as appropriate. Therefore, for example, a gap may be formed between a part of the inner surface of the resin member 15 and a part of the outer peripheral surface of the case 4.

[0031] The outer peripheral surface of the case 4 and the inner surface of the resin member 15 may be fixed to each other by using an adhesive or the like, or by providing a fitting structure on at least one of the outer peripheral surface of the case 4 and the inner surface of the resin member 15 to restrict the relative movement of the two. Alternatively, the resin member 15 may be simply supported to such an extent that it does not fall off the case 4 by the frictional force generated between the outer peripheral surface of the case 4 and the inner surface of the resin member 15. Furthermore, when the case 4 is made of resin, the resin member 15 and the case 4 may be integrally formed. Furthermore, although the resin member 15 in this embodiment is exemplified as being annular, the annular shape referred to here is not limited to a perfect circle. Specifically, the resin member 15 may be, for example, elliptical in shape, or annular in shape having radially extending protrusions or recesses on a part of its outer peripheral surface or inner peripheral surface, or annular in shape having recesses or through holes formed at any position, in accordance with the shape of the mounting portion, i.e., the outer periphery of the stator assembly 1.

[0032] For the resin member 15, an insulating resin having elasticity, particularly a thermoplastic resin, may be used. For example, PPS (polyphenylene sulfide) may be used as the thermoplastic resin. The thermoplastic resin may include not only the above-mentioned PPS, but also PET (polyethylene terephthalate), PP (polypropylene), PEEK (polyether ether ketone), PBT (polybutylene terephthalate), LCP (liquid crystal polymer), PPA (polyphthalamide), PEK (polyether ketone), PSU (polysulfone) / PES (polyphenylene sulfide), PEI (polyetherimide), PAI (polyamide imide), m-PPE (modified polyphenylene ether), PA (polyamide), or a combination thereof, and may contain a filler such as glass fiber in some cases. Furthermore, other resins such as PI (polyimide), fluororesin, PC (polycarbonate), PBT (polybutylene terephthalate), PE (polyethylene), POM (polyacetal), PS (polystyrene), PAR (polyarylate), PSF (polysulfone), ABS resin, and PET (polyethylene) can also be used alone or in combination.

[0033] In the resin member 15 of the present embodiment, before the resin molding is performed, a part of the upper surface 15A side of the resin member 15 can become a crushed portion (sometimes called a "crush margin") 16 that is mainly crushed when pressed against a die 20 described later. As shown in FIG. 2, the crushed portion 16 can be, for example, a region between the upper surface 15A of the resin member 15 and a position extending downward along the axial direction by a predetermined length H (for example, 0.1 to 0.5 mm). In the present embodiment, for the purpose of facilitating understanding, the crushed portion 16 is defined as the portion of the resin member 15 on which the pressing force acts most strongly when pressed against the die 20, but the portion of the resin member 15 that is crushed when pressed against the die 20 is not limited to only the portion shown as the crushed portion 16. For example, a case in which the entire resin member 15 is crushed almost uniformly is also included in the scope of the present disclosure. The length H of the crushed portion 16 may be set mainly in consideration of the axial dimension of the stator to be manufactured. In this embodiment, the axial dimension of the stator to be manufactured is set by the die 20. Details will be described later.

[0034] Fig. 3 is a schematic cross-sectional view showing an example of an apparatus for performing the manufacturing method of a stator according to the first embodiment of the present disclosure. In the manufacturing method of a stator according to the present embodiment, as shown in Fig. 3, resin molding can be performed using a mold 20. The mold 20 includes at least an upper mold 21 and a lower mold 22. Then, the resin molding can be performed by injecting molding resin into the mold 20 with the stator assembly 1 including the above-mentioned resin member 15 sandwiched between the upper mold 21 and the lower mold 22.

[0035] The upper die 21 is disposed on one end (upper end in FIG. 3) of the stator assembly 1 in the axial direction. The upper die 21 can be configured as a substantially disk-shaped member having an injection passage 23 provided therein and an outer diameter dimension larger than that of the stator assembly 1. The upper die 21 may be provided with a substantially cylindrical upper protrusion 24 provided in the center of the surface facing the lower die 22, an upper recess 25 formed in a substantially annular shape so as to surround the outer periphery of the position where the upper protrusion 24 is provided and capable of accommodating a part of the upper part of the stator assembly 1, and an upper annular protrusion 26 extending from the outer periphery toward the lower die 22 and having a tip capable of abutting against the upper surface 15A of the resin member 15. The injection passage 23 can be formed in the upper die 21 so as to connect between the surface opposite to the surface facing the lower die 22 of the upper die 21 and one or more points in the upper recess 25. In addition, the surface at the tip side of the upper protrusion 24 is substantially composed of a flat surface, and a positioning protrusion 27 may be provided at approximately the center thereof for positioning the upper mold 21 and the lower mold 22 in a direction intersecting the axial direction.

[0036] The lower die 22 is disposed on the other end (lower end in FIG. 3) side in the axial direction of the stator assembly 1. The lower die 22 can be configured as a substantially disk-shaped member having external dimensions similar to those of the upper die 21. The lower die 22 may be provided with a lower protrusion 28 provided in the center of the surface facing the upper die 21 and having a tip end capable of abutting on the tip end of the upper protrusion 24, a lower recess 29 formed in a substantially annular shape so as to surround the outer periphery of the position where the lower protrusion 28 is provided and capable of accommodating a part of the stator assembly 1 including the above-mentioned resin member 15, and a lower annular protrusion 30 extending from the outer periphery of the lower die 22 facing the upper annular protrusion 26 toward the upper die 21 and having a part of a tip end capable of abutting on the lower surface 15B of the resin member 15. The surface on the tip side of the lower projection 28 is substantially flat like the surface on the tip side of the upper projection 24, and a positioning recess 31 into which the positioning protrusion 27 of the upper mold 21 is fitted may be provided in the approximate center thereof. Note that, although the upper mold 21 and the lower mold 22 are both formed from approximately disk-shaped members in the embodiment, the outer shapes of the upper mold 21 and the lower mold 22 are not limited thereto, and they may also be formed from, for example, rectangular members.

[0037] Hereinafter, a method for manufacturing a stator according to the present embodiment will be described by way of example mainly with reference to Figs. 4 and 5. In the following description, a case where resin molding is performed on the above-mentioned stator assembly 1 using a mold 20 will be exemplified, but the structure of the stator assembly 1 is not limited to the above. In addition, a case where transfer molding is performed as a specific method of resin molding will be described as an example, but the present disclosure is not limited to this. As a specific method of resin molding, cast molding or injection molding can also be adopted. In addition, a thermosetting resin such as an epoxy resin or a phenolic resin, or a thermoplastic resin can be adopted as the molding resin MR (see Fig. 7) used in the resin molding.

[0038] Fig. 4 is a flow chart showing an example of a method for manufacturing a stator according to the first embodiment of the present disclosure. Fig. 5 is an enlarged view of part B in Fig. 3, in which Fig. 5(A) shows a state before the tip of the upper annular protrusion 26 of the upper die 21 comes into contact with the resin member 15, Fig. 5(B) shows a state in which the tip of the upper annular protrusion 26 of the upper die 21 comes into contact with the upper surface 15A of the resin member 15, and Fig. 5(C) shows a state in which the crushed portion 16 of the resin member 15 is crushed by the tip of the upper annular protrusion 26 of the upper die 21.

[0039] In order to manufacture a stator having a predetermined axial length, the method of manufacturing a stator according to this embodiment includes at least the steps of providing a stator assembly having a stator core with coils wound around a plurality of teeth protruding from a yoke (corresponding to step S1 described later), disposing an annular resin member around the outer periphery of the stator assembly, at least a portion of which is crushed when pressed against a die (corresponding to step S2 described later), sandwiching the stator assembly with the resin member disposed between an upper die and a lower die in a pressed state (corresponding to step S8, etc. described later), and injecting molding resin into the die (corresponding to step S9 described later). These steps will be described in detail below.

[0040] In the method of manufacturing a stator according to this embodiment, first, as shown in Fig. 4, a stator assembly 1 as shown in Fig. 1 is provided (step S1). In this embodiment, the stator assembly 1 provided in step S1 includes, in addition to a stator core 2 having a coil 3 wound around a plurality of teeth 6 protruding from a yoke 5, a case 4 surrounding the outer periphery of the stator core 2, and a busbar unit 9 including a busbar 10 connected to the coil.

[0041] After the stator assembly 1 is provided, a resin member 15 is then disposed so as to annularly cover the outer periphery of the stator assembly 1, specifically, a part of the outer periphery of the case 4 (step S2). At this time, it is preferable that the inner periphery of the resin member 15 is supported by at least partially abutting against the outer surface of the case 4.

[0042] In this embodiment, after the above-mentioned steps S1 and S2, or in parallel with the above-mentioned steps, the mold 20 is preheated (step S3). This preheating is preferably performed on at least a part of the mold 20, including at least the portion that contacts the resin member 15. In this embodiment, the entire upper mold 21 is preheated. The preheat temperature of the mold 20 is preferably approximately the same as or higher than the softening temperature of the resin member 15.

[0043] After the resin member 15 is attached to the stator assembly 1 and the mold 20 is preheated, the stator assembly 1 with the resin member 15 attached is then disposed in the mold 20 so as to be sandwiched between the upper mold 21 and the lower mold 22 (step S4). At this time, the lower part of the stator assembly 1 is accommodated in the lower recess 29 of the lower mold 22, and the upper part of the stator assembly 1 faces the upper recess 25 of the upper mold 21.

[0044] Here, the dimension between the upper die 21 and the lower die 22 of the die 20 in which the stator assembly 1 is disposed is adjusted to a predetermined dimension set as the axial length of the stator to be manufactured. Specifically, the distance between the upper recess 25 and the lower recess 29 when the upper protrusion 24 of the upper die 21 and the lower protrusion 28 of the lower die 22 abut against each other is set in advance so as to match the axial dimension of the stator to be manufactured. In contrast, the axial dimension of the stator assembly 1 does not need to match the distance between the upper recess 25 and the lower recess 29 when the upper protrusion 24 of the upper die 21 and the lower protrusion 28 of the lower die 22 abut against each other, and may be adjusted to be the same as or smaller than the distance. Therefore, high dimensional accuracy is not required when manufacturing the stator assembly 1.

[0045] Furthermore, when the upper projection 24 of the upper die 21 and the lower projection 28 of the lower die 22 come into contact with each other, a predetermined gap is formed between the tip surface of the upper annular projection 26 and the tip surface of the lower annular projection 30. In relation to this, the axial dimension of the resin member 15 is adjusted in accordance with the dimension of the gap. Specifically, the axial dimension of the resin member 15 is adjusted to be slightly larger (for example, about 0.1 to 0.5 mm) than the above-mentioned gap between the tip surface of the upper annular projection 26 and the tip surface of the lower annular projection 30. The above-mentioned portion of the resin member 15 that is adjusted to be slightly larger can function as the squashing portion 16.

[0046] When the stator assembly 1 is disposed in the die 20, next, as shown in Fig. 5(A), an operation is started to move at least one of the upper die 21 and the lower die 22 in a direction to relatively approach each other. Specifically, the upper die 21 starts to descend (step S5). Note that, although the present embodiment illustrates an example in which only the upper die 21 is operated, only the lower die 22, or both the upper die 21 and the lower die 22 may be operated.

[0047] When the upper die 21 starts to descend and a predetermined time has elapsed, the upper annular protrusion 26 of the upper die 21 comes into contact with the upper surface 15A of the resin member 15 (step S6). Here, since the upper die 21 has been preheated in step S3 to a temperature substantially equal to or higher than the softening temperature of the resin member 15, the crushing portion 16 including the upper surface 15A in contact with the upper die 21 is heated and softened mainly by heat from the upper die 21. When the crushing portion 16 is heated and softened, it is advisable to adjust the preheating temperature of the upper die 21 so that the crushing portion 16 does not melt and a gap does not form between the upper die 21 and the resin member 15.

[0048] In the above-mentioned step S6, the upper protrusion 24 of the upper die 21 and the lower protrusion 28 of the lower die 22 are not in contact with each other. This is because the axial dimension of the resin member 15 is previously adjusted to be larger by the amount of the crushed portion 16 formed. Therefore, the dimension between the upper recess 25 and the lower recess 29 in the state of step S6 is larger than the axial length of the stator to be manufactured. Therefore, the upper die 21 continues to descend even after the tip surface of the upper annular protrusion 26 comes into contact with the upper surface 15A of the resin member 15.

[0049] The lowering operation of the upper die 21 is continued until the height position of the upper die 21 reaches a preset specified height position, as shown in FIG. 5(B) (step S7). Here, the preset height position may be a height position where the dimension between the upper recess 25 and the lower recess 29 is the same as the axial dimension of the stator to be manufactured. In this embodiment, the upper die 21 is lowered to a position where the tip surface of the upper protrusion 24 of the upper die 21 abuts on the tip surface of the lower protrusion 28 of the lower die 22. Then, when it is detected that the upper protrusion 24 and the lower protrusion 28 abut, as shown in FIG. 5(C), the lowering of the upper die 21 is stopped (step S8). In this embodiment, the height position where the dimension between the upper recess 25 and the lower recess 29 is the same as the axial dimension of the stator to be manufactured is adjusted in advance to a position where the upper protrusion 24 contacts the lower protrusion 28, but is not limited thereto. For example, the height position of the descending upper die 21 may be detected by a known sensor, and the descending operation of the upper die 21 may be stopped when the upper die 21 reaches a preset height position.

[0050] When the tip surface of the upper annular projection 26 of the upper die 21 comes into contact with the upper surface 15A of the resin member 15 and the upper die 21 is further lowered, the resin member 15 is pressed against the upper die 21 and crushed. Here, the outer periphery of the resin member 15 sandwiched between the upper annular projection 26 and the lower annular projection 30 is not covered by the die 20. Therefore, the crushed portion 16 of the resin member 15 softened by the heat from the preheated upper die 21 is allowed to move partially outward as it is pressed against the upper die 21. Note that, in this embodiment, a case where the crushed portion 16 is softened by preheating the upper die 21 is exemplified, but preheating the upper die 21 is not essential. In this case, for example, the stator assembly 1 can be preheated using a well-known heating means or the like before being placed in the mold 20, or the stator assembly 1 having the resin member 15 arranged thereon can be placed in a preheated lower mold 22 to soften the resin member 15, or the crushed portion 16 can be plastically deformed by only the pressing force of the upper mold 21.

[0051] Furthermore, the axial length between upper recess 25 and lower recess 29 when upper projection 24 and lower projection 28 are in contact with each other is set to be the same as a predetermined length set for the stator to be manufactured. Stator assembly 1 housed between upper recess 25 and lower recess 29 is resin molded while housed in mold 20, thereby manufacturing a stator adjusted to a desired axial height. In other words, it can be said that the axial length of the stator manufactured by the method according to the present embodiment is determined based on the dimensions of mold 20.

[0052] When the stator assembly 1 including the resin member 15 is clamped in the mold 20 by the above-mentioned series of steps, next, injection of the mold resin MR into the mold 20 is started (step S9). Injection of the mold resin MR can be realized by operating a supply source connected to one end of the injection passage 23 of the upper mold 21, for example, a plunger (not shown). The supplied mold resin MR is injected mainly into the slots 7 via the injection passage 23. At this time, the upper surface 15A and the lower surface 15B of the resin member 15 are pressed against the upper annular protrusion 26 and the lower annular protrusion 30 by steps S6 to S8, so that the contact surface between the resin member 15 and the mold 20 is liquid-tight. This prevents the mold resin MR injected into the mold 20 from leaking out of the mold 20. Note that the term "liquid-tight" here refers to a sealed state to the extent that gas may pass through but liquid (including the molten mold resin MR) cannot pass through.

[0053] Once the injection of the molding resin MR is complete, the injected molding resin MR is hardened (step S10). To harden the molding resin MR, if the molding resin MR is a thermosetting resin, the molding resin MR may be heated using a known heating means (for example, by operating a heater (not shown) disposed in the mold 20). Also, if the molding resin MR is a thermoplastic resin, the molding resin MR may be cooled using a known cooling means. Once the hardening of the molding resin MR is complete, the mold 20 is removed from the stator assembly 1 (step S11), and the series of manufacturing steps is completed.

[0054] FIG. 6 is a cross-sectional view showing a state after the stator assembly shown in FIG. 2 has been resin-molded. The stator assembly 1 that has been resin-molded through the above-mentioned series of steps can function as a stator. As shown in FIG. 6, the stator is in a state where the entire surface of the resin member 15, except for a part thereof, is covered with the mold resin MR. The axial length of the part of the resin member 15 of the stator shown in FIG. 6 that is not covered with the mold resin MR may be shorter than the axial length of the resin member 15 before the resin molding is performed. This is because the crushed portion 16 has been crushed by the upper die 21 and the lower die 22 in the above-mentioned series of steps.

[0055] When resin molding is performed in this embodiment, a part of the resin member 15 is crushed, so that the dimensions inside the mold 20, particularly the dimension between the upper recess 25 and the lower recess 29, can be adjusted to a desired dimension while maintaining the liquid-tightness of the mold 20. The axial length of the stator manufactured in this manner can be specified by the dimension between the upper recess 25 and the lower recess 29 of the mold 20 when the molding resin MR is injected. Therefore, it is possible to suppress the variation in product height without requiring high dimensional accuracy when manufacturing each component that constitutes the stator. In addition, since the crushed resin member 15 is disposed between the upper annular protrusion 26 and the lower annular protrusion 30 that constitute the outer periphery of the mold 20 when the molding resin MR is injected, the inside of the mold 20 can be reliably made liquid-tight.

[0056] The resin member 15 included in the stator manufactured by the above-mentioned process is fixed as a part of the stator by hardened molding resin MR, etc. This fixed resin member 15 can be used as a mounting bracket, positioning rib, etc., used when installing a motor including the stator at a predetermined position.

[0057] As described above, in the manufacturing method of the stator according to the present embodiment, it is possible to make the height of the product uniform after resin molding while keeping the dimensional accuracy required for each member constituting the stator low by employing the resin member 15. In addition, since the resin member 15 having a predetermined elasticity abuts against the end of the mold 20 when the molding resin MR is injected, it is also possible to prevent resin leakage during resin molding.

[0058] In the first embodiment described above, the upper surface 15A and the lower surface 15B of the resin member 15, the tip surface of the upper annular protrusion 26 of the upper mold 21, and the tip surface of the lower annular protrusion 30 of the lower mold 22 are all flat surfaces, but the present disclosure is not limited to this. Therefore, some modified examples of the resin member and the mold are described below. In the modified examples described below, the same reference numerals are used for the parts similar to those in the configuration of the first embodiment described above, and their description is omitted, and only the parts changed from the first embodiment described above are described. In addition, some modified examples described below can be applied in combination within a range in which their functions can be maintained.

[0059] 7(A) is an enlarged view corresponding to FIG. 5, showing a modified example of the resin member. In one modified example of the present embodiment, instead of the above-mentioned resin member 15, a resin member 40 having a first annular protrusion 41 on a surface that abuts against the die 20 is adopted. The resin member 40 can be configured as an annular member that covers a part of the outer periphery of the stator assembly 1 and is coaxial with the stator assembly 1. The axial length of the resin member 40 is adjusted to be shorter than the axial length of the stator assembly 1, and an upper surface 40A that abuts against the upper die 21 can be formed above the resin member 40, and a substantially flat lower surface 40B that abuts against the lower die 22 can be formed below the resin member 40.

[0060] As shown in FIG. 7A, the first annular protrusion 41 is provided on the upper surface 40A of the resin member 40, which is the surface that contacts the upper die 21. The first annular protrusion 41 constitutes a part of the crushing portion of the resin member 40. The first annular protrusion 41 is, for example, a protruding stripe having a semi-elliptical cross section, and extends over the entire circumference of the upper surface 40A of the resin member 40, which extends in an annular shape. In this embodiment, the first annular protrusion 41 is provided on the upper surface 40A as an example, but the number of the first annular protrusion 41 may be two or more, and the first annular protrusion 41 may be provided on the lower surface 40B of the resin member 40, which is the surface that contacts the lower die 22, instead of or in addition to the upper surface 40A of the resin member 40.

[0061] As shown in the above-described modified example, by employing a resin member including the first annular protrusion 41, the volume of the portion of the resin member that is crushed by the mold 20 can be reduced. Therefore, the amount of resin that moves mainly to the outer periphery of the resin member 40 when pressed by the mold 20 is reduced, and the amount of change in the outer diameter of the resin member 40 before and after resin molding can be suppressed. Furthermore, when the resin member 40 is pressed by the mold 20, the portion of the first annular protrusion 41 is crushed preferentially, so that the first annular protrusion 41 is reliably crushed over the entire circumference, and the liquid-tightness of this portion can be stably ensured.

[0062] Fig. 7(B) is an enlarged view corresponding to Fig. 5, showing a modified mold. In the modified example shown in Fig. 7(A) described above, a protrusion is provided on the resin member side, but an annular protrusion may be provided on the mold side in consideration of obtaining a similar effect. Specifically, for example, as shown in Fig. 7(B), a second annular protrusion 42 may be provided on the surface of the upper mold 21 that contacts the resin member 15.

[0063] As shown in FIG. 7B, the second annular protrusion 42 is provided on the tip surface of the upper annular protrusion 26, which is the surface that contacts the resin member 15 of the upper mold 21. The second annular protrusion 42 is, for example, a protruding stripe having a semicircular cross section, and extends over the entire circumference of the annularly extending tip surface of the upper annular protrusion 26. Note that, in the present embodiment, one second annular protrusion 42 is provided on the tip surface of the upper annular protrusion 26, but the number of second annular protrusions 42 may be two or more, and the second annular protrusions 42 may be provided on the tip surface side of the lower annular protrusion 30, which is the surface that contacts the resin member 15 of the lower mold 22, instead of or in addition to the tip surface side of the upper annular protrusion 26 of the upper mold 21.

[0064] As shown in the other modified example described above, by employing a mold including the second annular protrusion 42, it is possible to form a portion with a large amount of crushing when the resin member 15 is crushed using the mold 20. This makes it possible to locally increase the density of the resin member 15 after it has been crushed, and it is possible to more reliably suppress resin leakage from the portion where the resin member 15 and the mold 20 come into contact when the molding resin MR is injected into the mold 20. In addition, it is possible to expect the same effect as that described in the modified example described above.

[0065] <Second embodiment> In the first embodiment described above, the stator assembly includes a case, but the stator assembly provided in the stator manufacturing method of the present disclosure does not have to include a case. Therefore, below, as a second embodiment of the present disclosure, a method for manufacturing a stator using a stator assembly 1A that does not include a case will be briefly described. Note that in the second embodiment described below, the same reference numerals are used to designate the same parts as those described in the first embodiment, and their description will be omitted, and the description will focus on the parts that are different from those in the first embodiment described above.

[0066] FIG. 8 is a schematic cross-sectional view showing an example of an apparatus for performing a manufacturing method of a stator according to a second embodiment of the present disclosure. As shown in FIG. 8, a stator assembly 1A provided in the manufacturing method of a stator according to this embodiment has an outer periphery of a stator core 2 exposed to the outside, and is not covered by a case 4 as in the stator assembly 1 of the first embodiment described above. Therefore, at least a part of the inner periphery of a resin member 50 disposed around the outer periphery of the stator assembly 1A abuts on the outer periphery of the stator core 2. Note that, although the present embodiment illustrates a case in which the resin member 50 abuts on the outer periphery of the stator core 2, it is not necessarily required that the resin member 50 and the stator assembly 1A abut on each other. Therefore, the resin member 50 may be disposed around the outer periphery of the stator assembly 1A in a state in which the resin member 50 is spaced apart from the stator assembly 1A.

[0067] The mold 20A used in this embodiment may have a structure similar to that of the mold 20 used in the first embodiment described above. More specifically, the mold 20A used in this embodiment differs from the mold 20 described above mainly in that lower support pins 33 for supporting the bottom of the stator core 2 at multiple points protrude upward from the bottom surface of the lower recess 29 of the lower mold 22. The lower support pins 33 are provided to form a gap into which the molding resin MR flows between the bottom surface of the lower recess 29 and the bottom surface of the stator core 2 so that the bottom of the stator assembly 1A is reliably covered by the molding resin MR since the stator assembly 1A is not covered by a case. It is preferable that a plurality of the lower support pins 33 are arranged in the lower recess 29 at predetermined intervals.

[0068] Fig. 9 is a plan view of the resin member shown in Fig. 8. The resin member 50 can be configured as an annular member coaxial with the stator assembly 1, covering the outer periphery of the stator assembly 1A, i.e., a part of the outer periphery of the stator core 2. The axial length of the resin member 50 is adjusted to be shorter than the axial length of the stator assembly 1A, and an upper surface 50A that abuts against the upper die 21 can be formed above the resin member 50, and a substantially flat lower surface 50B that abuts against the lower die 22 can be formed below the resin member 50. In addition, the inner circumferential surface of the resin member 50 is provided with a plurality of protrusions 51 that extend inward and have their tips abutting against the outer circumferential surface of the stator assembly 1A.

[0069] Since the resin molding in the manufacturing method of the stator according to the present embodiment aims to improve the heat dissipation performance of the coil 3, the molded resin MR needs to cover at least the inside of the stator core 2. On the other hand, if the molded resin MR is also made to cover the outer part of the stator assembly 1A, it is expected to have an effect of protecting the stator core 2 from external forces and the like. On the other hand, in the manufacturing method of the stator according to the present disclosure, since the resin member is disposed around the outer periphery of the stator core 2, if the molded resin MR is also filled on the outside of the stator assembly 1, the flow of the molded resin MR is hindered by the resin member, and the molded resin MR may not reach the area below the stator core 2, which may cause a filling failure. In the manufacturing method of the stator according to the present embodiment, the above-mentioned multiple protrusions 51 are adopted for the resin member 50 in consideration of the above points. If the resin member 50 is provided with multiple protrusions 51, the area where the stator assembly 1A and the resin member 50 contact each other can be reduced. Therefore, a passage through which the molding resin MR can pass can be secured between the outer periphery of the stator assembly 1A and the inner circumferential surface of the resin member 50 on which the protrusions 51 are not provided, and filling defects can be suppressed.

[0070] By using the stator assembly 1A and the die 20A configured as described above, the method for manufacturing a stator according to the present embodiment can be carried out. The method for manufacturing a stator according to the present embodiment can manufacture a stator by carrying out steps generally similar to those of the method for manufacturing a stator according to the first embodiment shown in FIG. 4. Therefore, the following will briefly explain an outline of the method for manufacturing a stator according to the present embodiment, using the reference numerals shown in FIG. 4. Note that the following will mainly explain characteristic steps of the method for manufacturing a stator according to the present embodiment, and the explanation of steps similar to those of the method for manufacturing a stator according to the first embodiment will be omitted, as the contents explained in the first embodiment will be used.

[0071] In the method for manufacturing a stator according to the present embodiment, first, a stator assembly 1A is provided (step S1). Next, a resin member 50 is disposed in an annular shape to cover the outer periphery of the stator assembly 1A, specifically, a part of the outer periphery of the stator core 2 (step S2). At this time, the resin member 50 is supported by abutting a protrusion 51 formed on its inner periphery against the outer periphery of the stator core 2.

[0072] Next, the stator assembly 1A with the resin member 50 attached is disposed in the mold 20A so as to be sandwiched between the upper mold 21 and the lower mold 22 (step S4). At this time, the stator assembly 1A is accommodated in the lower recess 29 by placing the lower surface of the stator core 2 on the lower support pins 33 formed in the lower recess 29 of the lower mold 22.

[0073] When the stator assembly 1A is disposed in the die 20A, the upper die 21 starts to descend (step S5). The descending operation of the upper die 21 continues until the upper die 21 reaches a specified height position while crushing a part of the resin member 50 during the descending operation (steps S7 and S8). When the stator assembly 1A including the resin member 50 is clamped in the die 20A by the above-mentioned operation, an injection operation of the molding resin MR into the die 20A starts (step S9). The injection of the molding resin MR is injected mainly into the slots 7, the lower space of the stator assembly 1A, and the outer periphery of the stator core 2 via the injection passage 23 of the upper die 21. The molding resin MR flowing around the outer periphery of the stator core 2 is filled via the space formed between the outer periphery of the stator core 2 and the inner circumferential surface of the resin member 50. When the injection of the molding resin MR is completed, the injected molding resin MR is cured (step S10), and then the die 20A is removed from the stator assembly 1A (step S11), completing a series of manufacturing steps.

[0074] Fig. 10 is a cross-sectional view showing the stator after the stator assembly is resin-molded by the method according to the second embodiment. As shown in Fig. 10, the stator manufactured through the above-mentioned manufacturing process has the entire circumference of the stator assembly 1A, including the outer periphery and bottom surface, covered with the molded resin MR. Note that a part of the resin member 50, specifically, a part sandwiched between the upper annular protrusion 26 of the upper die 21 and the lower annular protrusion 30 of the lower die 22, is not covered with the molded resin MR. The part of the resin member 50 that is not covered with the molded resin MR can be used as an attachment bracket, a positioning rib, or the like used when installing a motor including the stator at a predetermined position.

[0075] The method for manufacturing a stator according to this embodiment can also provide the same effects as those described in the above-mentioned first embodiment. In addition, by providing the protrusions 51 on the resin member 50, it is possible to prevent the occurrence of insufficient filling even when the stator assembly 1A does not have a case.

[0076] <Third embodiment> In the above-described first and second embodiments, the resin members 15, 40, 50 are exemplified as having axial lengths sufficiently shorter than the axial length of the stator assemblies 1, 1A, but the axial length of the resin members is not particularly limited. Therefore, a method for manufacturing a stator employing a resin member 60 whose axial length is adjusted to be longer than the axial length of the stator core will be described below as a third embodiment.

[0077] 11 is a schematic cross-sectional view showing an example of an apparatus for performing a method for manufacturing a stator according to a third embodiment of the present disclosure. Here, the stator assembly provided in the method for manufacturing a stator according to this embodiment can be the same as the stator assembly 1A used in the second embodiment described above. That is, a stator can be manufactured using the stator assembly 1A without a case. In the third embodiment described below, the same reference numerals are used to designate the same parts as those described in the first and second embodiments, and the description thereof is omitted, and the description will focus on the parts different from those in the above-mentioned embodiments.

[0078] Resin member 60 used in the manufacturing method of a stator according to this embodiment can be configured as an annular member whose axial length is adjusted to be substantially the same as the axial length of stator assembly 1A, as shown in Fig. 11. In this embodiment, upper surface 60A of resin member 60 before resin molding is performed can be adjusted to be located on the same plane as the upper end of stator assembly 1A, and lower surface 60B can be adjusted to be located slightly below the lower end of stator assembly 1A.

[0079] The resin member 60 may have an inner diameter adjusted to fit the shape of the outer periphery of the stator assembly 1A. Specifically, the inner surface of the resin member 60 may be provided with a first step 61 on which the lower surface of the stator core 2 is placed and a second step 62 on which a part of the busbar support member 11 is placed, and the inner diameter may be adjusted in stages with each step 61, 62 as a boundary. By making the inner surface of the resin member 60 have the above-mentioned structure, the stator assembly 1A can be stably supported inside the resin member 60.

[0080] Moreover, the mold 20B used in this embodiment may have a structure similar to that of the mold 20 used in the first embodiment described above. More specifically, the mold 20B used in this embodiment may be similar to the mold 20 except that the lower surface 60B of the resin member 60 abuts against the bottom of the lower recess 29 of the lower mold 22, the lower annular protrusion 30 is positioned so as to support the outer surface of the resin member 60, and the height of the upper annular protrusion 26 of the upper mold 21 is relatively low. As described above, since the lower surface 60B of the resin member 60 abuts against the bottom of the lower recess 29, the resin member 60 is sandwiched between the lower recess 29 and the upper annular protrusion 26.

[0081] By using the stator assembly 1A and the mold 20B configured as described above, the method for manufacturing a stator according to the present embodiment can be carried out. The method for manufacturing a stator according to the present embodiment can manufacture a stator by carrying out steps generally similar to those of the method for manufacturing a stator according to the first embodiment shown in FIG. 4. Therefore, the following will briefly explain an outline of the method for manufacturing a stator according to the present embodiment, using the reference numerals shown in FIG. 4. Note that the following will mainly explain characteristic steps of the method for manufacturing a stator according to the present embodiment, and as for steps similar to those of the method for manufacturing a stator according to the first embodiment, the contents explained in the first embodiment will be used, and explanations thereof will be omitted below.

[0082] In the method for manufacturing a stator according to the present embodiment, first, a stator assembly 1A is provided (step S1). Next, a resin member 60 is disposed in an annular shape to cover the entire outer periphery of the stator assembly 1A, which mainly includes the outer periphery of the stator core 2 and the outer periphery of the busbar unit 9 (step S2).

[0083] Next, the stator assembly 1A to which the resin member 60 is attached is disposed in the mold 20B so as to be sandwiched between the upper mold 21 and the lower mold 22 (step S4). At this time, the lower surface of the resin member 60 is placed in the lower recess 29 of the lower mold 22, so that the stator assembly 1A is supported by the lower mold 22.

[0084] When the stator assembly 1A is disposed in the die 20B, the upper die 21 starts to descend (step S5). The descending operation of the upper die 21 continues until the upper die 21 reaches a specified height position while crushing a part of the resin member 60 during the descending operation (steps S7 and S8). When the stator assembly 1A including the resin member 60 is clamped in the die 20B by the above-mentioned operation, the injection operation of the molding resin MR into the die 20B starts (step S9). The injection of the molding resin MR is injected mainly into the slots 7 and spaces formed above and below the stator assembly 1A via the injection passage 23 of the upper die 21. When the injection of the molding resin MR is completed, the injected molding resin MR is cured (step S10), and then the die 20A is removed from the stator assembly 1A (step S11), and a series of manufacturing steps is completed.

[0085] Fig. 12 is a cross-sectional view showing the stator after resin molding of the stator assembly by the method according to the third embodiment. As shown in Fig. 12, the stator manufactured through the above-mentioned manufacturing process has the entire outer periphery of the stator core 2 covered with the resin member 60, so that the resin member 60 functions in the same manner as the case 4 in the first embodiment. For this reason, in the third embodiment, the case 4 of the stator assembly 1 including the case 4 is made of resin, and the resin case 4 can be deformed so as to be crushed and sandwiched between the upper mold 21 and the lower mold 22 in the same manner as the above-mentioned resin member 60.

[0086] The method for manufacturing a stator according to this embodiment can also provide the same effects as those described in the above-mentioned first embodiment. In addition, since the resin member 60 is used to cover the entire outer periphery of the stator core 2, damage to the stator core 2, etc. caused by external forces, etc. can be suppressed.

[0087] As an option, the resin members 15, 40, 50, and 60 exemplified in the above-described respective embodiments and the bus bar support member 11 may be formed as an integrated resin member.

[0088] In addition, as an option, in each of the above-described embodiments, the resin members 15, 40, 50, 60 are left on the stator as part of the stator, but the resin members 15, 40, 50, 60 may be removed from the stator as a final product by trimming or the like.

[0089] The present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure. All of these modifications are included in the technical concept of the present disclosure. In the present disclosure, each component may be present in one or more of the above-described embodiments, provided that no contradiction occurs. [Explanation of symbols]

[0090] 1, 1A stator assembly 2 Stator core 3 Coil 4 Cases 9 Busbar unit 15, 40, 50, 60 Resin material 15A, 40A, 50A, 60A top 15B, 40B, 50B, 60B Bottom 16, 42 Crushing section 20, 20A, 20B mold 21 Upper mold 22 Lower mold 41 First annular protrusion 42 Second annular protrusion 51 protrusion 61 First protrusion 62 Second protrusion MR molding compound

Claims

1. A method for manufacturing a stator having an axial length set to a predetermined dimension, comprising the steps of: Providing a stator assembly including a stator core having a coil wound around a plurality of teeth protruding from a yoke; a step of arranging an annular resin member around an outer periphery of the stator assembly, at least a portion of which is crushed when pressed against a die, the die including an upper die disposed at one end side of the stator assembly in the axial direction, and a lower die disposed at the other end side of the stator assembly in the axial direction; a step of clamping the stator assembly, on which the resin member is disposed, between the upper die and the lower die in a state in which the resin member is pressed, wherein a dimension between the upper die and the lower die when the stator assembly, on which the resin member is disposed, is clamped is adjusted to the predetermined dimension; and injecting a molding resin into the mold. A method for manufacturing a stator.

2. The resin member is made of a thermoplastic resin, The method further includes a step of preheating at least a portion of the mold including a portion that contacts the resin member. A method for manufacturing a stator according to claim 1 .

3. the resin member has a first annular protrusion on at least one of a surface that contacts the upper die and a surface that contacts the lower die; A method for manufacturing a stator according to claim 1 .

4. a second annular protrusion is provided on a surface of at least one of the upper mold and the lower mold that contacts the resin member; A method for manufacturing a stator according to claim 1 .

5. The stator assembly further includes a case surrounding an outer periphery of the stator core, and the step of disposing the resin member includes disposing the resin member around the outer periphery of the case. A method for manufacturing a stator according to claim 1 .

6. The resin member has an inner peripheral surface provided with a plurality of protrusions extending inward and having tip portions abutting against an outer peripheral surface of the stator assembly. A method for manufacturing a stator according to claim 1 .

7. The resin member is a cylindrical member having an axial length longer than the axial length of the stator core. A method for manufacturing a stator according to claim 1 .

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