Manufacturing method of stator

Abstract

To provide a manufacturing method of a stator, capable of effectively suppressing a resin leakage when a resin mold is performed with a simple construction.SOLUTION: A manufacturing method of a stator of the present disclosure, comprises: a step of providing a stator assembly; a step that is a step of housing the stator assembly into a metal mold having an upper metal mold that has an upper side contact piece that can be contacted to the stator assembly and a lower side contact piece that can be contacted to the stator assembly; a step of distributing an annular-shaped resin member in order to seal the metal mold to an external part of the stator assembly; a step of relatively moving at least one of the upper metal mold and the lower metal mold in a direction where they approach each other; a step of continuing a relative movement while crushing the resin member by the upper metal mold and the lower metal mold; a step of stopping the relative movement when detecting that the upper side contact piece is contacted to the stator assembly; 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] The inner surface of a stator constituting a rotating electric machine, for example an induction motor, is resin molded (sealed with resin) for heat dissipation and insulation (see, for example, Patent Document 1 below). When performing this resin molding, the resin molding is generally performed by placing a stator assembly including a stator core around which a coil is wound 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 Laid-Open No. 60-002044 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, for example, the stator core of a stator constituting a motor may be formed by stacking a plurality of iron core pieces (also called core pieces) made of relatively thin electromagnetic steel sheets. In a stator core formed by stacking a plurality of iron core pieces, if there is a slight variation in the thickness of each iron core piece, the variation may be amplified in the process of stacking the iron core pieces, and the variation in the axial length may be large (for example, in units of 0.1 to 1 mm). If there is such a variation in the axial length of the stator core of the stator assembly, when resin molding is performed using a specific mold, a gap may occur between the mold depending on the stator assembly, or a gap may occur between the mold and the stator assembly, making it impossible to fix the stator assembly in the mold. Therefore, in order to eliminate the occurrence of the gap, it becomes necessary to adjust the dimensions, stroke, etc. of the mold every time the stator assembly is changed, which is a factor that reduces work efficiency.

[0005] In view of the above-mentioned problems, an object of the present disclosure is to provide a method for manufacturing a stator that is capable of effectively suppressing resin leakage during resin molding with a simple configuration. [Means for solving the problem]

[0006] In order to achieve the above object, a method for manufacturing a stator according to a first aspect of the present disclosure includes a step of providing a stator assembly including a stator core having a coil wound around a plurality of teeth protruding from a yoke, and a step of housing the stator assembly in a mold, the mold including: an upper mold disposed on one end side of the stator assembly in the axial direction and having an upper abutment piece that is capable of abutting against the stator assembly at a position facing the stator assembly; and a lower mold disposed on the other end side of the stator assembly in the axial direction and having a lower abutment piece that is capable of abutting against the stator assembly at a position facing the stator assembly; The method includes the steps of placing the stator assembly on the lower mold so that its lower surface abuts against the lower abutment piece; arranging an annular resin member for sealing the inside of the mold on the outside of the stator assembly; moving at least one of the upper mold and the lower mold relatively toward each other to bring an end of the upper mold and an end of the lower mold into contact with the resin member; continuing the relative movement while crushing at least a portion of the resin member between the upper mold and the lower mold; stopping the relative movement when it is detected that the upper abutment piece has abutted against the stator assembly; and injecting molding resin into the mold.

[0007] In the above-described method of manufacturing a stator, when the upper and lower dies are moved relative to each other, the resin member is first brought into contact with the upper and lower dies, and then the stator assembly is sandwiched between the upper and lower abutment pieces while crushing the resin member, so that resin molding of a plurality of stator assemblies whose axial lengths of the stator cores are slightly different can be performed by sealing the inside of the die without adjusting the die, etc. Therefore, it is possible to easily prevent resin leakage.

[0008] A method for manufacturing a stator according to a second aspect of the present disclosure is 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 including the portions of the upper mold and the lower mold that abut 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 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.

[0011] 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.

[0012] A fourth aspect of the present disclosure relates to a method for manufacturing a stator according to any one of the first to third aspects of the present disclosure, wherein the upper abutment piece and the lower abutment piece are composed of a plurality of support pins extending toward the stator core from a plurality of positions facing the stator core of the stator assembly contained within the upper mold or the lower mold.

[0013] In the above-described method for manufacturing a stator, the contact piece is formed of a plurality of support pins, so that it can directly contact and be supported by the stator core.

[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 resin member includes an annular protrusion on at least one of a surface abutting the upper mold and a surface abutting the lower mold.

[0015] 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.

[0016] A stator manufacturing method according to a sixth aspect of the present disclosure is a stator manufacturing method according to any one of the first to fifth aspects of the present disclosure, wherein the method includes an annular protrusion on a surface of at least one of the upper mold and the lower mold that abuts against the resin member.

[0017] 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. Effect of the Invention

[0018] According to the method for manufacturing a stator disclosed herein, it is possible to effectively prevent resin leakage during resin molding with a simple configuration. [Brief description of the drawings]

[0019] [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] 6 is an explanatory diagram showing an operation example of a state when a manufacturing method of the stator shown in FIG. 5 is carried out, the operation being illustrated by enlarging a portion B of FIG. 4. FIG. [Figure 6] 6 is an explanatory diagram showing an operation example of a state when a manufacturing method of the stator shown in FIG. 5 is carried out, the operation being illustrated by enlarging a portion B of FIG. 4. FIG. [Figure 7] 6 is an explanatory diagram showing an operation example when a manufacturing method of the stator shown in FIG. 5 is performed, the diagram showing an enlarged view of a portion B in FIG. 4. FIG. [Figure 8] 1 is a perspective view showing an example of a stator manufactured by a stator manufacturing method according to a first embodiment of the present disclosure. [Figure 9] 9 is a cross-sectional view taken along line CC in FIG. 8. [Figure 10] 13 is an enlarged view showing a modified example of the resin member and the mold. FIG. [Figure 11] 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 12] 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] 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.

[0021] <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.

[0022] The stator core 2 may be configured by stacking a plurality of (e.g., tens to hundreds) iron core pieces made of relatively thin electromagnetic steel sheets. The stator core 2 may include an annular member having a central axis X, a yoke 5 formed in a circular, for example, cylindrical shape, and a plurality of (24 in FIG. 1) teeth 6 protruding inward from the inner peripheral surface of the yoke 5. The teeth 6 are arranged at substantially 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 an example and are not limited thereto. The extending direction of the central axis X may also be simply referred to as the "axial direction" hereinafter.

[0023] 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).

[0024] 1 is wound around the teeth 6 so as to have a generally elongated rectangular shape with the axial direction of the stator core 2 as viewed from the radial direction of the stator core 2. The shape of the wound coil 3 is not limited to the generally elongated rectangular shape described above, and may be a square or a horizontally elongated rectangular shape according to the shape of the teeth 6, etc. The coil end 3A constituting the end of the coil 3 may be drawn out from one end of the slot 7 in the axial direction to the outside of the slot 7 (e.g., upward). The number of electric wires wound as the coil 3 may be one or more. In place of the above-mentioned insulator 8, other insulating members, such as insulating paper and varnish, may be used.

[0025] 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.

[0026] In the stator assembly 1 having the above-described configuration, an annular resin member 15 is disposed to seal the inside of the mold 20 during resin molding. As shown in Figs. 1 and 2, this resin member 15 can be configured as an annular member coaxial with the stator assembly 1 so as to cover the outside of the stator assembly 1, more specifically, a part of the outer periphery of the stator core 2. The resin member 15 of this embodiment can form a part of the stator S (see Fig. 8).

[0027] 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 against which an upper die 21 described later comes into contact may be formed above the resin member 15, and an approximately flat lower surface 15B against which a lower die 22 described later comes into contact may be formed below the resin member 15. In this embodiment, the upper surface 15A and the lower surface 15B are both approximately flat in shape, but the present disclosure is not limited thereto, and the surfaces do not have to be flat as long as they can seal the inside of the die 20, more specifically, can maintain the contact points in a liquid-tight state when they come into contact with the upper die 21 and the lower die 22.

[0028] In addition, as shown in FIG. 1, the inner peripheral surface of the resin member 15 according to the present embodiment is provided with a plurality of (for example, eight equally spaced apart along the circumferential direction) protrusions 17 that extend inward and whose tips abut the outer peripheral surface of the stator core 2. The protrusions 17 abut against the outer periphery of the stator core 2, so that the resin member 15 can be attached to the outside of the stator assembly 1. Furthermore, by employing the above-mentioned protrusions 17 for the resin member 15, a gap can be secured between the resin member 15 and the stator core 2, so that the flow of the molding resin is less likely to deteriorate in that portion. Note that, in the present embodiment, the resin member 15 has the protrusions 17 formed on its inner surface, and the protrusions 17 abut against the outer peripheral surface of the stator core 2, but is not limited thereto. In other words, as long as the structure is capable of supporting the resin member 15 against the stator assembly 1, the shape of the inner surface of the resin member 15 or the outer peripheral surface of the stator assembly 1 can be appropriately changed.

[0029] In addition, the movement of the outer peripheral surface of the stator core 2 and the tip of the protrusion 17 may be restricted by using an adhesive or the like, or by providing a structure for receiving the tip of the protrusion 17 on the outer peripheral surface of the stator core 2. Alternatively, the resin member 15 may be simply supported to such an extent that it does not fall off the stator core 2 by the frictional force generated between the outer peripheral surface of the stator core 2 and the tip of the protrusion 17. 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.

[0030] 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.

[0031] 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 1 mm). In this 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. However, 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 variation in the axial length of the stator core 2.

[0032] 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 is performed using a die 20. The die 20 includes at least an upper die 21 and a lower die 22. The above-mentioned stator assembly 1 is accommodated between the upper die 21 and the lower die 22, and molding resin MR (see Fig. 8, etc.) is injected into the die 20, whereby resin molding can be performed.

[0033] The upper die 21 is disposed on one end side (the upper end side in FIG. 3 ) in the axial direction of the stator assembly 1. 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 an upper fitting portion 24 formed as a substantially cylindrical depression 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 fitting portion 24 is provided and capable of accommodating a part of the upper portion of the stator assembly 1, and an upper annular protrusion 26 extending from the outer periphery of the upper die 21 toward the lower die 22 and having a tip capable of abutting against the upper surface 15A of the resin member 15.

[0034] Of the above-mentioned configuration, injection passage 23 can be formed in upper mold 21 so as to connect between the surface of upper mold 21 opposite the surface facing lower mold 22 and one or more locations in upper recess 25. Moreover, upper fitting portion 24 is provided mainly to guide insertion of lower fitting portion 28, which will be described later, and the depth of the bottom surface of upper fitting portion 24 is preferably adjusted so as not to come into contact with the tip surface of lower fitting portion 28 even at the timing of injecting molding resin MR.

[0035] Moreover, in the present embodiment, an upper support pin 27 is provided at a position of upper die 21 facing stator assembly 1, more specifically, at a position of the bottom surface of upper recess 25 facing stator core 2, as an example of an upper abutment piece that abuts against stator assembly 1. A plurality of upper support pins 27 may be erected at a predetermined interval from the bottom surface of upper recess 25 toward lower die 22. The upper support pins 27 may be disposed at a position where a tip of the upper support pin 27 can directly abut against the upper surface of stator core 2 when upper die 21 moves in a direction approaching lower die 22, for example. The tip shape of upper support pin 27 is not particularly limited, but is preferably, for example, configured as a substantially flat surface.

[0036] The lower die 22 is disposed on the other end side (the lower end side in FIG. 3) 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 fitting portion 28 provided in the center of the surface facing the upper die 21 and having a tip portion insertable into the upper fitting portion 24, a lower recess 29 formed in a substantially annular shape so as to surround the outer periphery of the position where the lower fitting portion 28 is provided and capable of accommodating a part of the above-mentioned stator assembly 1, 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 portion abutting against the lower surface 15B of the resin member 15.

[0037] Further, in the present embodiment, a lower support pin 31 is provided at a position of the lower die 22 facing the stator assembly 1, more specifically, at a position of the bottom surface of the lower recess 29 facing the stator core 2, as an example of a lower abutment piece that abuts against the stator assembly 1. A plurality of lower support pins 31 may be erected at a predetermined interval from the bottom surface of the lower recess 29 toward the upper die 21. The arrangement of the lower support pins 31 may be such that, for example, when the stator assembly 1 is placed on the lower die 22, the tip of the lower support pin 31 can directly abut against the lower surface of the stator core 2. Further, the tip shape of the lower support pin 31 is not particularly limited, but it is preferable that the tip is substantially flat, for example, because the stator assembly 1 can be stably placed on the lower die 22.

[0038] In this embodiment, the upper mold 21 and the lower mold 22 are both formed from approximately disk-shaped members, but the external shapes of the upper mold 21 and the lower mold 22 are not limited to this and can also be formed from, for example, rectangular members.

[0039] Hereinafter, a method for manufacturing a stator according to the present embodiment will be described by way of example mainly with reference to FIG. 4 and FIG. 5 to FIG. 7. In the following description, a case where resin molding is performed on the above-mentioned stator assembly 1 using a mold 20 will be described as an example, 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. 8) used in the resin molding.

[0040] 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, and Figs. 5 to 7 are enlarged views of part B in Fig. 4, illustrating an example of a state when the method for manufacturing a stator shown in Fig. 5 is performed, in a chronological order.

[0041] A method for manufacturing a stator according to this embodiment mainly includes a step of providing a stator assembly including a stator core having a coil wound around a plurality of teeth protruding from a yoke (corresponding to step S1 described later), and a step of accommodating the stator assembly in a mold (corresponding to step S3 described later), in which the mold includes an upper mold that is disposed on one end side of the stator assembly in the axial direction and has an upper abutment piece that is capable of abutting against the stator assembly at a position facing the stator assembly, and a lower mold that is disposed on the other end side of the stator assembly in the axial direction and has a lower abutment piece that is capable of abutting against the stator assembly at a position facing the stator assembly, and the stator assembly is arranged such that its lower surface abuts against the lower abutment piece. The process includes a step of placing the stator assembly on the lower die as shown in FIG. 1, a step of disposing an annular resin member for forming a part of the stator and sealing the inside of the die on the outside of the stator assembly (corresponding to step S4 described later), a step of relatively moving at least one of the upper die and the lower die in a direction approaching each other to bring an end of the upper die and an end of the lower die into contact with the resin member (corresponding to step S6 described later), a step of continuing the relative movement while crushing the resin member between the upper die and the lower die (corresponding to step S7 and the like described later), a step of stopping the relative movement when it is detected that the upper contact piece has contacted the stator assembly (corresponding to step S8 described later), and a step of injecting molding resin into the die (corresponding to step S9 described later). The steps are described in detail below.

[0042] 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 a stator core 2 having a coil 3 wound around a plurality of teeth 6 protruding from a yoke 5, as well as a busbar unit 9 including a busbar 10 connected to the coil.

[0043] At any timing before or after providing the stator assembly 1, the mold 20 is preheated (step S2). This preheating is preferably performed on a part of the mold 20 including at least a 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.

[0044] The provided stator assembly 1 is then housed in the die 20; more specifically, the provided stator assembly 1 is placed on the lower die 22 (step S3). At this time, the lower part of the stator assembly 1 is housed in the lower recess 29 of the lower die 22, and the lower surface of the stator assembly 1 is supported by the lower support pins 31. The upper part of the stator assembly 1 faces the upper recess 25 of the upper die 21.

[0045] Next, an annular resin member 15 is disposed on the outside of the stator assembly 1 (outside the stator core 2 in this embodiment) (step S4). At this time, the inner peripheral surface of the resin member 15 is supported by the protrusion 17 that abuts against the outer surface of the stator core 2. In addition, the lower surface 15B of the resin member 15 at this time may be brought into contact with the lower annular protrusion 30 that constitutes the end of the lower die 22. As described above, this resin member 15 includes the crushed portion 16 that is crushed when pressed against the die 20. Therefore, the axial length of the resin member 15 prepared in this step is adjusted to be larger than the length between the upper annular protrusion 26 and the lower annular protrusion 30 at the time of step S8 described later. Note that the above-mentioned "outside the stator assembly" includes the axial end of the stator assembly 1 in addition to the outer periphery of the stator assembly 1. The resin member 15 disposed outside the stator assembly 1 is not limited to being disposed on the outside of the stator core 2 as illustrated in FIG.

[0046] When the stator assembly 1 is disposed in the die 20 and the resin member 15 is disposed on the stator assembly 1, then, as shown in Fig. 5, an operation is started to move at least one of the upper die 21 and the lower die 22 in a direction to approach each other relatively. Specifically, the upper die 21 starts to descend (step S5). The descending operation is continued until the upper support pin 27 abuts against the stator core 2. 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 in a direction to approach each other.

[0047] When the upper die 21 starts to descend and a predetermined time has elapsed, as shown in FIG. 6, the upper annular protrusion 26 constituting the end of the upper die 21 comes into contact with the upper surface 15A of the resin member 15 (step S6). Here, the axial length of the resin member 15 at this point is adjusted to be sufficiently long so that it comes into contact with the end of the upper die 21 before the descent of the upper die 21 is completed. Therefore, regardless of the variation in the axial length of the stator core 2 of the stator assembly 1 to be resin molded, the upper surface 15A of the resin member 15 comes into contact with the upper annular protrusion 26 of the upper die 21 before the upper support pin 27 comes into contact with the stator core 2. Then, in this embodiment, the lowering operation of the upper die 21 continues until the upper support pin 27 comes into contact with the stator core 2, so that the lowering operation of the upper die 21 is not stopped even after the upper annular protrusion 26 comes into contact with the resin member 15.

[0048] Incidentally, the upper die 21 is preheated in step S2 to a temperature substantially equal to or higher than the softening temperature of the resin member 15. Therefore, the crushed portion 16 including the upper surface 15A that contacts the upper annular protrusion 26 of the upper die 21 in step S6 is heated mainly by heat from the upper die 21 and starts to soften. When the crushed portion 16 is heated and softened, it is advisable to adjust the preheat temperature of the upper die 21 so that the crushed portion 16 does not melt and a gap does not form between the upper die 21 and the resin member 15.

[0049] The lowering operation of the upper die 21 continues until the upper support pin 27 of the upper die 21 abuts against the upper surface of the stator core 2 (step S7). Then, when it is detected (for example, using a sensor or the like, not shown) that the upper support pin 27 abuts against the stator core 2, the lowering operation of the upper die 21 is stopped as shown in FIG. 7 (step S8). In this way, if the timing for stopping the lowering operation of the upper die 21 is specified based on the contact between the upper support pin 27 and the stator core 2, even if there is variation in the axial height of the stator core 2, the upper die 21 can always be stopped at an appropriate height position just by monitoring the contact between the upper support pin 27 and the stator core 2. Note that even when the lowering operation of the upper die 21 is stopped, the gap G is maintained between the bottom of the upper fitting portion 24 and the tip of the lower fitting portion 28. By adjusting the overall length of the upper fitting portion 24 and / or the lower fitting portion 28 so as to always ensure this gap G, the upper support pin 27 and the stator core 2 can be brought into reliable contact with each other.

[0050] As explained as step S7, when the upper annular protrusion 26 constituting the end portion 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 and crushed by the upper annular protrusion 26. Here, the outer periphery side of the resin member 15 sandwiched between the upper annular protrusion 26 and the lower annular protrusion 30 is not covered by the die 20. Therefore, a part of the resin member 15 pressed and crushed by the upper die 21 is allowed to move to the outer periphery of the resin member 15 described above.

[0051] In the present embodiment, the case where the crushed portion 16 is softened by preheating the upper die 21 is exemplified, but it is not essential to preheat the upper die 21. When the upper die 21 is not preheated, for example, it is possible to adopt a mode in which the stator assembly 1 is preheated using a known heating means or the like before being disposed in the die 20, or the resin member 15 is softened by disposing the stator assembly 1 having the resin member 15 disposed thereon in a preheated lower die 22, or the crushed portion 16 is plastically deformed only by the pressing force of the upper die 21.

[0052] Once the stator assembly 1 including the resin member 15 has been clamped within the die 20 by the series of steps described above, injection of the molding resin MR into the die 20 begins (step S9). Injection of the molding resin MR can be achieved by operating a supply source, such as a plunger (not shown), connected to one end of the injection passage 23 of the upper die 21. The supplied molding resin MR is injected mainly into the slots 7 via the injection passage 23.

[0053] Incidentally, as in the present embodiment, the axial length of the stator core 2 formed by stacking a plurality of iron core pieces may vary as described above. However, in the manufacturing method of the stator according to the present embodiment, as described in steps S6 to S8, a process is adopted in which the resin member 15 is brought into contact with the upper annular protrusion 26 of the upper die 21 before the upper support pin 27 is brought into contact with the stator core 2. Therefore, the variation in the axial length of the stator core 2 is absorbed by changing the amount of squeezing of the resin member 15, and no gap is formed between the resin member 15 and the upper die 21 and the lower die 22. Therefore, even without the need for a cumbersome task of adjusting the dimensions of the die one by one in accordance with the variation in the axial length of the stator core 2, a liquid-tight state can always be easily achieved at the boundary between the resin member 15 and the die 20, and the injected molding resin MR can be effectively prevented from leaking out of the die 20. Note that liquid-tightness here refers to a sealed state in which gas may pass through but liquid (including liquid or paste-like molding resin MR) cannot pass through.

[0054] When the injection of the above-mentioned mold resin MR is completed, the injected mold resin MR is hardened (step S10). If the mold resin MR is a thermosetting resin, the mold resin MR may be hardened by heating the mold resin MR using a known heating means (for example, by operating a heater (not shown) arranged in the die 20). If the mold resin MR is a thermoplastic resin, the mold resin MR may be cooled by a known cooling means. As the mold resin MR hardens, the stator assembly 1 and the resin member 15 are fixed together. In the present embodiment, the resin member 15 is fixed to the stator assembly 1 by the hardened mold resin MR as an example, but the two may be fixed together at the timing when the resin member 15 is disposed outside the stator assembly 1.

[0055] When the above-mentioned hardening of the molding resin MR is completed, the mold 20 is removed from the stator assembly 1 (step S11), and the series of manufacturing steps is completed.

[0056] FIG. 8 is a perspective view showing an example of a stator manufactured by the manufacturing method of a stator according to the first embodiment of the present disclosure. FIG. 9 is a cross-sectional view taken along the line CC in FIG. 8. The stator S obtained by performing the above-mentioned series of steps has its outer periphery covered with the molded resin MR as shown in FIG. 8 and FIG. 9. Here, the resin member 15 disposed on the stator assembly 1 in the above-mentioned step S4 is fixed to the stator assembly 1 by the molded resin MR or by an adhesive or the like used to restrict the movement of the resin member 15 relative to the stator assembly 1. The resin member 15 fixed to the stator assembly 1 in this manner may be used as a part of the stator S as a final product, or may be removed by trimming or the like after the resin molding including the above-mentioned series of steps.

[0057] When the stator S manufactured by the above-mentioned process includes the resin member 15, the resin member 15 can be used as a mounting bracket, a positioning rib, or the like, which is used when installing a motor including the stator S at a predetermined position. When the resin member 15 is not used as a part of the stator S, a process of removing the resin member 15 from the stator S from which the mold 20 has been removed may be carried out after the above-mentioned process S11.

[0058] As described above, in the manufacturing method of the stator according to the present embodiment, by employing the resin member 15, even if there is variation in the axial length of the stator core 2, it is possible to reliably seal the boundary portion between the end of the mold 20 and the resin member 15. Therefore, it is possible to prevent resin leakage when the molding resin MR is injected into the mold 20.

[0059] FIG. 10 is an enlarged view showing a modified example of the resin member and the mold. In FIG. 10, the contact portion between the resin member 15 and the upper annular protrusion 26 is shown in an enlarged manner. In the above-mentioned first embodiment, the surfaces of the resin member 15 that contact the upper mold 21 and the lower mold 22 are both flat surfaces, but the present disclosure is not limited thereto. For example, one or more annular protrusions may be formed on at least one of the upper surface 15A and the lower surface 15B, which are the surfaces of the resin member 15 that contact the upper mold 21 and the lower mold 22. More specifically, as shown in FIG. 10(A), an annular protrusion 41 can be provided on the upper surface 15A of the resin member 15. The annular protrusion 41 may be provided along the extension direction of the upper surface 15A of the resin member 15. When such an annular protrusion 41 is employed, the amount of resin that is crushed and moved when the resin member 15 is pressed by the mold 20 is reduced, and the amount of change in the outer diameter of the resin member 15 before and after the execution of the resin molding can be suppressed. Furthermore, when the resin member 15 is pressed by the mold 20, the annular projection 41 portion is crushed preferentially, so that the liquid-tightness of this portion can be stably ensured.

[0060] In the above-described first embodiment, the surfaces of the upper die 21 and the lower die 22 that come into contact with the resin member 15 are all flat, but the present disclosure is not limited thereto. For example, one or more annular protrusions may be formed on at least one of the tip surface of the upper annular protrusion 26 and the tip surface of the lower annular protrusion 30, which are the surfaces of the upper die 21 and the lower die 22 that come into contact with the resin member 15. More specifically, as shown in FIG. 10B, an annular protrusion 42 may be provided at a position facing the resin member 15 on the tip surface of the upper annular protrusion 26. The annular protrusion 42 may be provided along the extension direction of the upper surface 15A of the opposing resin member 15. By employing such an annular protrusion 42, when the resin member 15 is crushed using the die 20, a portion with a large amount of crushing can be formed. This allows the density of the resin member 15 after it has been crushed to be locally increased, and makes it possible to more reliably suppress resin leakage from the area where the resin member 15 and the mold 20 come into contact when the molding resin MR is injected into the mold 20.

[0061] <Second embodiment> In the above-mentioned first embodiment, the upper annular protrusion 26 of the upper die 21 and the lower annular protrusion 30 of the lower die 22 are exemplified to crush the resin member 15, but the shapes of the surfaces of the upper die 21 and the lower die 22 that contact the resin member 15 are not limited to the above-mentioned shapes. Therefore, as a second embodiment of the present disclosure, a case where a die 20A having a shape different from the die 20 used in the above-mentioned first embodiment is used will be briefly described below. In the second embodiment described below, the same reference numerals are assigned to the same parts as those described in the first embodiment, and the description thereof will be omitted, and the description will be centered on the parts different from those in the above-mentioned first embodiment.

[0062] Fig. 11 is a schematic cross-sectional view showing an example of an apparatus for performing a manufacturing method of a stator according to the second embodiment of the present disclosure. As shown in Fig. 11, a mold 20A used in the manufacturing method of a stator according to the present embodiment is composed of an upper mold 21A and a lower mold 22A. Of these, the upper mold 21A is composed of a substantially disk-shaped member having an injection passage 23 therein and an upper fitting portion 24 at the center of the surface facing the lower mold 22A, similar to the above-mentioned upper mold 21, and has an outer diameter dimension larger than the outer diameter of the stator assembly 1. On the other hand, this upper mold 21A is provided with an upper flat surface 32, the portion surrounding the outer periphery of the position where the upper fitting portion 24 is provided being flat.

[0063] Upper flat surface 32 has a function of forming a gap into which molding resin MR flows into the upper portion of stator assembly 1 by facing the upper portion of stator assembly 1, and also a function of contacting resin member 15 to seal inside of mold 20. In relation to this, a plurality of upper support pins 27 are provided at positions of upper flat surface 32 facing stator core 2, and ends of injection passages 23 are disposed thereon. In addition, a radially outer portion of upper flat surface 32 forms a surface that comes into contact with upper surface 15A of resin member 15.

[0064] Similarly to the above-described lower die 22, the lower die 22A can be configured as a substantially disk-shaped member having a lower fitting portion 28 and a lower recess 29 and having approximately the same outer dimensions as the upper die 21A. The lower die 22A is provided with a lower annular protrusion 33 that extends from the outer periphery of the lower die 22A toward the upper die 21A and a part of its tip can abut against the lower surface 15B of the resin member 15. The lower annular protrusion 33 differs from the lower annular protrusion 30 of the first embodiment in that the axial length of the lower annular protrusion 33 reaches a position close to the upper surface of the stator core 2 and a step is formed on the inside of the tip to avoid contact with the busbar unit 9.

[0065] The manufacturing method of the stator core in this embodiment can be configured by a process similar to the process described in the first embodiment with reference to Fig. 4. However, when the manufacturing method of the stator is performed using the above-mentioned mold 20A, the resin member 15 is disposed outside the busbar unit 9. Then, the resin member 15 disposed outside the busbar unit 9 has at least a part of its lower surface 15B in contact with the lower annular protrusion 33 and an upper surface 15A in contact with the radially outer surface of the upper flat surface 32, thereby sealing the inside of the mold 20A.

[0066] The method for manufacturing a stator according to this embodiment can also provide the same effects as those described in the above-mentioned embodiment 1. In addition, the shape of the mold used can be simplified, and the manufacture and maintenance of the mold can be simplified.

[0067] As an option, when resin member 15 is disposed adjacent to busbar unit 9 as in this embodiment, resin member 15 and busbar support member 11, which are also made of resin, can be molded integrally with each other. In this case, the number of parts of the stator can be reduced.

[0068] <Third embodiment> In the first and second embodiments described above, the case where a support pin is used as the first and second abutment pieces is exemplified, but the specific shapes of the first and second abutment pieces are not limited thereto. Therefore, as the third embodiment of the present disclosure, a case where a mold 20B having a shape different from the molds 20 and 20A used in the first and second embodiments described above is used will be briefly described below. Note that in the third embodiment described below, the same reference numerals are given to the same parts as those described in the first embodiment, and the description thereof is omitted, and the description will focus on the parts different from those in the first embodiment described above.

[0069] Fig. 12 is a schematic cross-sectional view showing an example of an apparatus for performing the manufacturing method of a stator according to the third embodiment of the present disclosure. As shown in Fig. 12, a mold 20B used in the manufacturing method of a stator according to the present embodiment is composed of an upper mold 21B and a lower mold 22B. Of these, the upper mold 21A may have a configuration similar to that of the above-mentioned upper mold 21. That is, the upper mold 21A can be composed of a substantially disk-shaped member having an injection passage 23 therein and an outer diameter dimension larger than the outer diameter of the stator assembly 1, and can be provided with an upper fitting portion 24, an upper recess 25, and an upper annular protrusion 26.

[0070] Moreover, the lower die 22B may be similar to the above-described lower die 22, except that a lower support step 34 is used as the lower abutment piece instead of the above-described lower support pin 31. That is, the lower die 22B can be configured as a substantially disk-shaped member including a lower fitting portion 28, a lower recess 29, and a lower annular protrusion 30, and having approximately the same outer dimensions as the upper die 21A.

[0071] A lower support step 34 is provided radially outward of the lower recess 29, extending in a direction approaching the stator assembly 1 and having its outer periphery connected to the inner surface of the lower annular protrusion 30. This lower support step 34 may be a circumferentially continuous annular step, or may be a step divided into a plurality of steps provided at predetermined intervals in the circumferential direction. The upper surface of the lower support step 34 is substantially flat, and the lower surface of the stator core 2 of the stator assembly 1 is placed on this upper surface, thereby supporting the stator assembly 1 on the lower die 22.

[0072] The manufacturing method of the stator core of this embodiment can be configured with a process similar to the process described in the first embodiment with reference to Fig. 4. However, when the manufacturing method of the stator is carried out using the above-mentioned die 20A, the lower part of the stator assembly 1 is placed on the lower support step 34 in the step of housing the stator assembly 1 in the die 20B.

[0073] The manufacturing method of the stator according to this embodiment can also provide the same effects as those described in the above-mentioned embodiment 1. In addition, by configuring the lower contact piece with the lower support step 34, the strength of the lower contact piece can be improved, and it becomes possible for the lower contact piece to stably contact and support the stator assembly 1.

[0074] In the second and third embodiments described above, the resin member 15 may be left on the stator S as a part of the stator S, which is the final product, or may be removed from the stator S by trimming or the like.

[0075] 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]

[0076] 1 Stator Assembly 2 Stator core 3 Coil 9 Busbar unit 15 Resin parts 15A top 15B Bottom 16 Crushing section 17 Protrusion 20, 20A, 20B mold 21, 21A, 21B upper mold 22, 22A, 22B Lower mold 23 Injection passage 24 Upper fitting part 25 Upper recess 26 Upper annular protrusion 27 Upper support pin (an example of an upper support piece) 28 Lower fitting part 29 Lower recess 30 Lower annular process 31 Lower support pin (an example of a lower support piece) 32 Upper flat surface 33 Lower annular process 34 Lower support step (another example of a lower support piece) 41, 42 Annular protrusion MR molding compound S stator

Claims

1. Providing a stator assembly including a stator core having a coil wound around a plurality of teeth protruding from a yoke; a step of housing the stator assembly in a mold, the mold comprising: an upper mold disposed at one end of the stator assembly in the axial direction and having an upper abutment piece capable of abutting against the stator assembly at a position facing the stator assembly; and a lower mold disposed at the other end of the stator assembly in the axial direction and having a lower abutment piece capable of abutting against the stator assembly at a position facing the stator assembly, the stator assembly being placed on the lower mold so that a lower surface of the stator assembly abuts against the lower abutment piece; disposing an annular resin member on an exterior of the stator assembly for sealing an interior of the mold; a step of relatively moving at least one of the upper mold and the lower mold in a direction approaching each other to bring an end of the upper mold and an end of the lower mold into contact with the resin member; continuing the relative movement while crushing at least a portion of the resin member between the upper mold and the lower mold; stopping the relative movement when it is detected that the upper contact piece has come into contact with the stator assembly; 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 part of the upper mold and the lower mold, the part including the part contacting the resin member. A method for manufacturing a stator according to claim 1 .

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

4. The upper abutment piece and the lower abutment piece are constituted by a plurality of support pins extending from a plurality of positions facing the stator core of the stator assembly accommodated in the upper die or the lower die toward the stator core. A method for manufacturing a stator according to claim 1 .

5. the resin member has an 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 .

6. a ring-shaped 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 .

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