Stator, motor, and method for manufacturing stator

Abstract

This stator has: a stator core in which a plurality of slots arranged in the circumferential direction are formed; an insulating member disposed on the inner surfaces of the plurality of slots; and a coil part disposed inside the insulating member in the plurality of slots. The insulating member has: a base material layer extending along the outer circumference of the coil part as viewed in the axial direction; and a foam layer positioned on one surface of the base material layer in the thickness direction in a state of being expanded by heating. The base material layer has a pair of protrusions that respectively protrude, in the axial direction of the stator core, from slot openings that respectively open in one axial direction and the other axial direction of the slots. The foam layer is positioned on one surface in the thickness direction of at least a part of each of the pair of protrusions. The thickness of a part of the insulating member where the foam layer is positioned in each of the protruding portions is larger than the distance between the inner surfaces of the slots in the slot openings and the outer surface of the coil part.

Description

Stator, motor, and method for manufacturing a stator

[0001] The present invention relates to a stator, a motor, and a method for manufacturing a stator. This application claims priority based on Japanese Patent Application No. 2024-177026 filed in Japan on October 9, 2024, the content of which is incorporated herein by reference.

[0002] There is known a stator in which an insulating member for insulating the coil with respect to the stator core is disposed between the inner surface of the slot of the stator and the coil. As the stator, there is disclosed a configuration of an electric motor in which a foaming material is provided on at least one side of an insulator inserted into a slot of the stator, and the foaming material is heated and foamed in the slot to fix the coil in the slot (for example, Patent Document 1).

[0003] Japanese Patent Laid-Open No. 60-93467

[0004] In the stator disclosed in Japanese Patent Laid-Open No. 60-93467, the heated and foamed foaming material pushes the coil in the slot from the outer periphery inward and adheres to the inner peripheral surface of the slot. Thus, in the stator, the coil is fixed in the slot by an insulator that insulates the coil with respect to the stator core. Therefore, in the stator, the coil can be fixed in the slot with a simple configuration.

[0005] However, in the stator, since the foaming material is foaming in the slot, it is impossible to easily confirm the foaming amount of the foaming material. Therefore, when the foaming amount is not sufficient, etc., there is a possibility that the insulator moves with respect to the slot or the coil moves with respect to the insulator. That is, in the stator, there is a possibility that the coil moves with respect to the slot.

[0006] Therefore, there is a need for a configuration that can suppress movement of the coil with respect to the slot with a simple configuration.

[0007] An object of the present invention is to provide a configuration that can suppress movement of the coil with respect to the slot with a simple configuration.

[0008] A stator according to an exemplary embodiment of the present invention comprises a stator core having a cylindrical core back portion extending in the axial direction, a plurality of teeth portions extending radially from the core back portion and arranged circumferentially, wherein a plurality of slots arranged circumferentially are formed between adjacent teeth portions in the circumferential direction, an insulating member disposed on the inner surface of the plurality of slots, and a coil portion disposed inside the insulating member within the plurality of slots. The insulating member has a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer located on one surface of the base material layer in the thickness direction, in a state of expansion due to heating. The base material layer has a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively. The foamed layer is located on one surface in the thickness direction of at least a portion of each of the pair of protrusions. Of the insulating member, the thickness of a portion of the portion where the foamed layer is located at the protrusion is greater than the distance between the inner surface of the slot at the slot opening and the outer surface of the coil portion.

[0009] A motor according to one exemplary embodiment of the present invention comprises a stator having the above-described configuration and a rotor arranged radially inward with respect to the stator.

[0010] A method for manufacturing a stator according to an exemplary embodiment of the present invention is a method for manufacturing a stator comprising: a stator core having a cylindrical core back portion extending in the axial direction and a plurality of teeth portions extending radially from the core back portion and arranged in the circumferential direction, wherein a plurality of slots arranged in the circumferential direction are formed between adjacent teeth portions in the circumferential direction; an insulating member disposed on the inner surface of the plurality of slots; and a coil portion disposed inside the insulating member within the plurality of slots, wherein the insulating member comprises a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer located on one surface in the thickness direction of the base material layer in an expanded state due to heating. The present invention provides an insulating sheet, which, when inserted into the slot, has a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively, and has a foaming agent that foams when heated placed on one surface in the thickness direction of at least a portion of each of the pair of protrusions; an insulating sheet insertion step of inserting the insulating sheet into the slot; a coil insertion step of inserting the coil portion into the insulating sheet; and an insulating member forming step of, with the insulating sheet and the coil portion inserted into the slot, heating the insulating sheet to foam the foaming agent and form a foamed layer, thereby forming an insulating member in which the thickness of a portion of the portion where the foamed layer is located on the protrusions is greater than the distance between the inner surface of the slot and the outer surface of the coil portion at the slot opening.

[0011] According to the present invention, a configuration can be provided that can suppress the movement of the coil relative to the slot with a simple configuration.

[0012] Figure 1 is a cross-sectional view showing an example of the schematic configuration of a motor according to Embodiment 1. Figure 2 is a cross-sectional view showing an example of the configuration of a stator according to Embodiment 1. Figure 3 is a perspective view showing an example of the configuration of a stator core. Figure 4 is a partially enlarged view of Figure 2. Figure 5 is a cross-sectional view of the stator cut along the line V-V in Figure 4. Figure 6 is a partial perspective view of the area around one slot of the stator. Figure 7A is a perspective view of the insulating member according to Embodiment 1, viewed in one direction. Figure 7B is a perspective view of the insulating member, viewed in a different direction than Figure 7A. Figure 8 is an exploded view showing an example of the configuration of the insulating member. Figure 9 is a partially exploded view showing another example of the configuration of the insulating member. Figure 10 is a partially exploded view showing another example of the configuration of the insulating member. Figure 11 is a diagram showing an example of the configuration of an insulating sheet. Figure 12 is a diagram showing the insulating sheet in a folded state. Figure 13 is a diagram showing the process of inserting the insulating sheet into the slots of the stator core. Figure 14 is a perspective view of a stator core with insulating sheets inserted into each of the multiple slots. Figure 15 is a schematic diagram showing the process of inserting the coil portion into the insulating sheet. Figure 16 shows another example of the configuration of the insulating sheet. Figure 17 is a diagram corresponding to Figure 5 of the stator according to Embodiment 2. Figure 18 is a diagram corresponding to Figure 5 of the stator according to Embodiment 3. Figure 19 is a diagram corresponding to Figure 4 of the stator according to another embodiment.

[0013] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. Note that identical or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. Furthermore, the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components or their dimensional ratios.

[0014] In the following description, the direction parallel to the central axis P of the motor 100 will be referred to as the axial direction, the direction perpendicular to the central axis P will be referred to as the radial direction, and the direction along the arc centered on the central axis P will be referred to as the circumferential direction. In each figure, the axial direction is indicated by A, the radial direction by R, and the circumferential direction by C. However, this definition of direction is not intended to limit the orientation of the motor 100 when it is in use.

[0015] Furthermore, in the following explanation, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing, etc.") include not only cases where components are directly fixed to each other, but also cases where they are fixed to each other via other components. In other words, in the following explanation, the expressions "fixing, etc." include both direct and indirect fixing of components to each other.

[0016] (Embodiment 1) (Motor Configuration) Figure 1 is a cross-sectional view showing an example of the schematic configuration of a motor 100. The motor 100 has a stator 2 and a rotor 3. The stator 2 is cylindrical and extends along the central axis P. The rotor 3 is cylindrical and extends along the central axis P, and is located radially inward of the stator 2. The rotor 3 rotates around the central axis P relative to the stator 2. The configuration of the rotor 3 is the same as in the conventional design. Therefore, a detailed explanation of the rotor 3 is omitted.

[0017] (Stator Configuration) Figure 2 is a cross-sectional view showing an example of the configuration of the stator 2. As shown in Figure 2, the stator 2 has a stator core 4, an insulating member 5, and a coil section 6. In Figure 2, for illustrative purposes, the hatch on the cross-section of the coil section 6 has been omitted.

[0018] Figure 3 is a perspective view showing an example of the configuration of the stator core 4. As shown in Figure 3, the stator core 4 is a cylindrical member. The stator core 4 has, for example, a plurality of plate-shaped electromagnetic steel sheets stacked in the thickness direction. Note that the stator core 4 may be composed of a cylindrical metal block instead of a plurality of plate-shaped electromagnetic steel sheets.

[0019] The stator core 4 has a core back portion 41 and a plurality of teeth portions 42. The core back portion 41 is cylindrical and extends axially A along the central axis P. The plurality of teeth portions 42 extend radially inward from the inner circumferential surface of the core back portion 41 and are arranged in the circumferential direction C. The radially inward tips of the plurality of teeth portions 42 face the outer circumferential surface of the rotor 3 in the radial direction R.

[0020] Slots 43 are formed between adjacent teeth 42 in the circumferential direction C. The multiple slots 43 are arranged in the circumferential direction C. The slots 43 are groove-shaped and extend in the axial direction A along the inner circumference of the stator core 4. The slots 43 have a pair of axial openings 43a that open in one axial direction and the other axial direction, respectively, and a radial opening 43b that opens radially inward. The axial openings 43a correspond to the slot openings of the present invention.

[0021] Figure 4 is a partially enlarged view of Figure 2. Figure 5 is a cross-sectional view of the stator 2 taken along the line V-V in Figure 4. Figure 6 is a partial perspective view of the area around one slot 43 of the stator 2. As shown in Figures 4 to 6, an insulating member 5 and a coil section 6 are arranged within the slot 43.

[0022] The insulating member 5 is a sheet-like member having electrical insulating properties. The insulating member 5 is placed on the inner surface of the slot 43. In this embodiment, as shown in Figure 5, the insulating member 5 covers the entire inner surface of the slot 43. However, the insulating member 5 may cover only a part of the inner surface of the slot 43. The insulating member 5 insulates the coil portion 6 from the stator core 4.

[0023] In this embodiment, as shown in Figure 4, the insulating member 5 is also arranged on the radial opening 43b side of the slot 43. That is, in this embodiment, the insulating member 5 is annular in shape and extends along the outer circumference of the coil portion 6 when viewed in the axial direction A. In other words, the insulating member 5 extends along the outer circumference of the coil portion 6 when viewed in the axial direction A. Hereinafter, for the purpose of explanation, the direction in which the insulating member 5 extends when viewed in the axial direction A will be referred to as the circumferential direction W of the insulating member.

[0024] The insulating member 5 has a base layer 51 and a foamed layer 52. The base layer 51 is a sheet-like member having electrical insulating properties. The base layer 51 extends in the circumferential direction W of the insulating member when viewed in the axial direction A. As shown in Figure 5, the base layer 51 has a slot arrangement portion 511 located within the slot 43 and a pair of protrusions 512 that project from the axial opening 43a in the axial direction A of the stator core 4.

[0025] A foamed layer 52 is located on one surface 51a in the thickness direction of the base layer 51. In this embodiment, one surface 51a in the thickness direction of the base layer 51 is located on the inside. The other surface 51b in the thickness direction of the base layer 51 is located on the outside. Therefore, the slot arrangement portion 511 of the base layer 51 is in contact with the inner surface of the slot 43.

[0026] As shown in Figures 4 to 6, the foamed layer 52 is located on one surface 51a in the thickness direction of the base layer 51 in an expanded state due to heating. The foamed layer 52 is located on one surface 51a in the thickness direction of at least a portion of each of the pair of protrusions 512. As described above, in this embodiment, one surface 51a in the thickness direction of the base layer 51 is located on the inside. That is, the foamed layer 52 is located on the surface of the base layer 51 on the coil portion 6 side. The foamed layer 52 is in contact with the coil portion 6 in an expanded state.

[0027] Furthermore, in this embodiment, the foam layer 52 is located on the entire surface of the base layer 51 on the coil portion 6 side. Therefore, the foam layer 52 includes an in-slot foam layer 521 located on the coil portion 6 side with respect to the slot arrangement portion 511, and an out-slot foam layer 522 located on the coil portion 6 side with respect to the pair of protrusions 512.

[0028] The expanded foam layer 52 located on the coil portion 6 side pushes the outer surface of the coil portion 6 inward into the slot 43. This prevents the coil portion 6 from moving relative to the insulating member 5.

[0029] Furthermore, the in-slot foam layer 521 located within the slot 43 of the foam layer 52 is in contact with the coil portion 6. The slot arrangement portion 511 located within the slot of the base layer 51 is in contact with the inner surface of the slot 43. This prevents the coil portion 6 from moving relative to the slot 43 by the insulating member 5.

[0030] The insulating member 5 is obtained by heating an insulating sheet 8 on which a foaming agent 9, which expands upon heating, is placed on one surface in the thickness direction. That is, the base layer 51 and the foamed layer 52 are formed by the heated insulating sheet 8 and the foaming agent 9, respectively. Details of the structure of the insulating member 5 and the method of forming the insulating member 5 will be described later.

[0031] The coil section 6 is positioned inside the insulating member 5 within the plurality of slots 43. The coil section 6 is composed of a plurality of conductors 6a. In this embodiment, the conductors 6a are flat rectangular wires. The conductor 6a has a main body portion that extends axially within the slot 43 and coil end portions that protrude axially A from one axial end face and the other axial end face of the stator core 4, respectively. The plurality of conductors 6a are connected to each other at the coil end portions. Details and illustrations of the coil end portions are omitted.

[0032] The coil section 6 is insulated from the stator core 4 by the insulating member 5 and is fixed to the slot 43 by the insulating member 5.

[0033] (Insulating Member) Next, an example of the insulating member 5 will be described in detail using Figures 4 to 8. Figure 7A is a perspective view of the insulating member 5 in one direction. Figure 7B is a perspective view of the insulating member 5 in a direction different from that of Figure 7A. Figure 8 is an exploded view showing an example of the configuration of the insulating member 5.

[0034] As shown in Figures 4 to 8, the base layer 51 is a sheet with a constant thickness. That is, in the base layer 51, the slot arrangement portion 511 located within the slot 43 and the pair of protrusions 512 that protrude from the axial opening 43a in the axial direction A of the stator core 4 have the same thickness.

[0035] As shown in Figures 4 to 7B, the base layer 51 has a first end 51c and a second end 51d located at one end and the other end in the circumferential direction W of the insulating member, respectively. The base layer 51 has corners 51e located between a portion extending radially along the inner surface of the slot 43 and portions extending circumferentially on the bottom surface side and the radial opening 43b side of the slot 43, respectively, when viewed in the axial direction A.

[0036] In this embodiment, the first end 51c and the second end 51d of the base layer 51 overlap in the thickness direction on the bottom side of the slot 43. For the purposes of explanation below, the end located on the inside of the first end 51c and the second end 51d will be referred to as the second end 51d.

[0037] As shown in Figures 4, 6 to 8, the protruding portion 512 of the base layer 51 has a notch 513 that extends in the axial direction. In this embodiment, each pair of protruding portions 512 has a notch 513 at the corner 51e of the first end portion 51c that is closest to the tip in the circumferential direction W of the insulating member.

[0038] As shown in Figures 4 and 5, the foamed layer 521 inside the slots of the foamed layer 52 has a thickness that fills the gap between the slot arrangement portion 511 and the outer surface of the coil portion 6. A portion of the foamed layer 522 outside the slots of the foamed layer 522 has a greater thickness than the foamed layer 521 inside the slots. The remaining portion of the foamed layer 522 outside the slots has a thickness equivalent to that of the foamed layer 521 inside the slots.

[0039] More specifically, in this embodiment, the portion of the outer-slot foam layer 522 extending in the radial direction R, and the portion extending in the circumferential direction C on the radial opening 43b side, have the same thickness as the inner-slot foam layer 521. The portion of the outer-slot foam layer 522 located on one surface 51a in the thickness direction of the second end 51d has the same thickness as the inner-slot foam layer 521. A portion of the outer-slot foam layer 522 located on one surface 51a in the thickness direction of the first end 51c has a greater thickness than the inner-slot foam layer 521.

[0040] In other words, a portion of the insulating member 5 that protrudes from the axial end face A of the stator core 4 and is located on the bottom side of the slot 43 has a thickness greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6. The portion of the insulating member 5 that has a thickness greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6 cannot move axially A toward the inside of the slot 43. Therefore, movement of the insulating member 5 in the axial direction A relative to the slot 43 is suppressed. In other words, the insulating member 5 having the above configuration is suppressed from moving relative to the slot 43.

[0041] Also, when viewed in the axial direction A, the foam layer 52 of the insulating member 5 presses the outer surface of the coil portion 6 inward of the slot 43. Thereby, movement of the coil portion 6 with respect to the insulating member 5 is suppressed. Therefore, a configuration capable of suppressing movement of the coil portion 6 with respect to the slot 43 can be provided with a simple configuration.

[0042] In FIGS. 4 to 8, the foam layer 52 of the insulating member 5 is located over the entire surface 51a on one side in the thickness direction of the base material layer 51. However, as shown in FIGS. 9 and 10, the foam layer 52 may be located on a part of the surface 51a on one side in the thickness direction in the protruding portion 512. FIGS. 9 and 10 are partial development views showing another example of the configuration of the insulating member 5. In FIGS. 9 and 10, for the sake of explanation, the portion where the foam layer 52 is located is hatched.

[0043] That is, the foam layer 52 may be located on the surface 51a on one side in the thickness direction in at least a part of the protruding portion 512. Note that it is preferable that the foam layer 52 is located on at least one of one side or the other side in the circumferential direction W of the insulating member with respect to the cut portion 513.

[0044] In the insulating member 5 having such a configuration, the thickness of a part of the portion where the foam layer 52 is located in the protruding portion 512 is larger than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6 at the axial opening 43a of the slot 43. Therefore, even with such a configuration, movement of the insulating member 5 in the axial direction A with respect to the slot 43 can be suppressed.

[0045] The stator 2 according to this embodiment has a stator core 4 having a cylindrical core back portion 41 extending in the axial direction A, and a plurality of tooth portions 42 extending radially R from the core back portion 41 and arranged in the circumferential direction C, with a plurality of slots 43 arranged in the circumferential direction C between adjacent tooth portions 42 in the circumferential direction C, an insulating member 5 disposed on the inner surface of the plurality of slots 43, and a coil portion 6 disposed inside the insulating member 5 within the plurality of slots 43. The insulating member 5 has a base layer 51 extending along the outer circumference of the coil portion 6 when viewed in the axial direction A, and a foamed layer 52 located on one surface in the thickness direction of the base layer 51 in an expanded state due to heating. The base layer 51 has a pair of protrusions 512 that protrude in the axial direction A of the stator core 4 from axial openings 43a that open in one axial direction and the other axial direction of the slots 43, respectively. The foam layer 52 is located on one surface in the thickness direction of at least a portion of each of the pair of protrusions 512. Of the insulating member 5, the thickness of a portion of the portion of the protrusion 512 where the foam layer 52 is located is greater than the distance between the inner surface of the slot 43 in the axial opening 43a and the outer surface of the coil portion 6.

[0046] Of the insulating member 5, the portion where the foam layer 52 is located in the protruding portion 512 has a thickness greater than the distance between the inner surface of the slot 43 in the axial opening 43a and the outer surface of the coil portion 6, so it cannot move axially A toward the inside of the slot 43. This prevents the insulating member 5 from moving axially A relative to the slot 43.

[0047] Furthermore, the expanded foam layer 52 pushes the outer surface of the coil portion 6 inward into the slot 43. This suppresses the movement of the coil portion 6 relative to the insulating member 5. Therefore, a configuration can be provided that suppresses the movement of the coil portion 6 relative to the slot 43 with a simple structure.

[0048] In this embodiment, the insulating member 5 has a corner portion 51e located between a portion extending in the radial direction R along the inner surface of the slot 43 and a portion extending in the circumferential direction C along the bottom surface of the slot 43. The protruding portion 512 has a cut portion 513 at the corner portion 51e closest to the tip in the circumferential direction W of the insulating member at the first end portion 51c located at one end in the circumferential direction W of the insulating member in the base material layer 51 among the first end portion 51c located at one end and the second end portion 51d located at the other end. The foaming layer 52 is located at least on one surface in the thickness direction between the tip of the first end portion 51c and the cut portion 513 in the protruding portion 512. In this embodiment, the pair of protruding portions 512 each have a cut portion 513.

[0049] As a result, in the pair of protruding portions 512, the regions between the tip in the circumferential direction W of the insulating member of the first end portion 51c and the cut portion 513 can be moved to positions outside the slot 43 when viewed in the axial direction A, respectively. Therefore, the foaming layer 52 can be easily expanded.

[0050] In this embodiment, the second end portion 51d of the protruding portion 512 is located on the side of the coil portion 6 with respect to the region between the tip of the first end portion 51c and the cut portion 513 and overlaps with the region in the thickness direction.

[0051] As a result, with the first end portion 51c moved to a position outside the slot 43 when viewed in the axial direction A, the second end portion 51d can be made to protrude in the axial direction A of the slot 43. Therefore, it is possible to prevent the coil portion 6 from contacting the end surface in the axial direction A of the stator core 4.

[0052] In this embodiment, the region between the tip of the first end portion 51c and the cut portion 513 in the protruding portion 512 is located on the bottom surface side of the slot 43 when viewed in the axial direction A.

[0053] When viewed in the axial direction A, a core back portion 41 is located radially outside the bottom surface of the slot 43. Therefore, the region between the tip of the first end portion 51c and the cut portion 513 in the protruding portion 512 can be moved to a position outside the slot 43 when viewed in the axial direction A without interfering with other members.

[0054] The motor 100 of this embodiment has a stator 2 having the configuration of this embodiment and a rotor 3 arranged radially inward with respect to the stator 2. This makes it possible to realize a motor 100 having a stator 2 in which movement of the coil portion 6 relative to the slot 43 is suppressed.

[0055] (Method for manufacturing a stator) Next, an exemplary method for manufacturing a stator 2 will be described with reference to Figures 11 to 15. The method for manufacturing a stator 2 includes a preparation step, a bending step, a notch formation step, an insulating sheet insertion step, a coil insertion step, and an insulating member formation step.

[0056] The preparation step involves preparing an insulating sheet 8 on which a foaming agent 9, which expands upon heating, is placed on one surface in the thickness direction. The insulating sheet 8 is the base layer 51 of the insulating member 5. The foaming agent 9 is the foamed layer 52 of the insulating member 5. The insulating sheet 8 is inserted into the slot 43 in the insulating sheet insertion step described later.

[0057] Figure 11 shows an example of the configuration of an insulating sheet 8 in which a foaming agent 9 is placed on one surface in the thickness direction. In Figure 11, a hatch is added to the portion of the insulating sheet 8 where the foaming agent 9 is placed for illustrative purposes.

[0058] As shown in Figure 11, the insulating sheet 8 is a rectangular sheet when viewed in the thickness direction. In the following description, each direction of the insulating sheet 8 is based on the orientation of the insulating sheet 8 when inserted into the slot 43. That is, of the longitudinal and transverse directions of the insulating sheet 8, the direction extending in the axial direction A when inserted into the slot 43 is called the axial direction A, and the direction intersecting the axial direction A is called the circumferential direction W of the insulating member.

[0059] The insulating sheet 8 has a portion that becomes the slot arrangement portion 511 of the insulating member 5 and a portion that becomes a pair of protrusions 512. The insulating sheet 8 also has a portion that becomes the first end 51c, a portion that becomes the second end 51d, and a portion that becomes the corner 51e of the insulating member 5. Hereinafter, the portion that becomes the slot arrangement portion 511, the portion that becomes the pair of protrusions 512, the portion that becomes the first end 51c, the portion that becomes the second end 51d, and the portion that becomes the corner 51e of the insulating sheet 8 will also be referred to as the slot arrangement portion 511, the pair of protrusions 512, the first end 51c, the second end 51d, and the corner 51e, respectively.

[0060] The bending process is the process of bending the insulating sheet 8. Figure 12 shows the insulating sheet 8 in a bent state. In this embodiment, as shown in Figure 12, the bending process involves bending the rectangular insulating sheet 8 toward the foaming agent 9 at a position where it is positioned at the corner of the slot 43, thereby forming a corner portion 51e extending in the axial direction A on the insulating sheet 8. In addition, the first end portion 51c and the second end portion 51d of the insulating sheet 8 are overlapped in the thickness direction. As a result, an annular insulating sheet 8 is formed in which the foaming agent 9 is located on the inner surface side when viewed in the axial direction A.

[0061] The notch formation process is a process of forming a notch in the insulating sheet 8 that extends in the axial direction A. That is, in the notch formation process, a portion that will become the notch 513 of the insulating member 5 is formed in the insulating sheet 8. Specifically, in the protruding portion 512, a notch extending in the axial direction A is formed at the corner 51e of the first end portion 51c that is closest to the tip in the circumferential direction W of the insulating member.

[0062] In the insulating sheet insertion process, the insulating sheet 8 is inserted into the slots 43 of the stator core 4. Figure 13 shows the process of inserting the insulating sheet 8 into the slots 43 of the stator core 4. Figure 14 is a perspective view of the stator core 4 with insulating sheets 8 inserted into each of the multiple slots 43.

[0063] In the coil insertion process, the coil portion 6 is inserted into the insulating sheet 8 which is placed in the slot 43. Figure 15 is a schematic diagram showing how the coil portion 6 is inserted into the insulating sheet 8.

[0064] In the insulating member formation process, the insulating member 5 is formed by heating the insulating sheet 8. Specifically, with the insulating sheet 8 and the coil portion 6 inserted into the slot 43, the foaming agent 9 is foamed by heating the insulating sheet 8. Note that heating the insulating sheet 8 includes not only directly heating the insulating sheet 8, but also indirectly heating the insulating sheet 8, for example by heating the stator core 4.

[0065] As a result, as shown in Figure 5, the region between the tip of the first end 51c of the protruding portion 512 in the circumferential direction W of the insulating member and the notched portion 513 moves to a position outside the slot 43 when viewed in the axial direction A. That is, an insulating member 5 is formed having a base layer 51 and a foamed layer 52, and the thickness of a portion of the part of the protruding portion 512 where the foamed layer 52 is located is greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6 at the axial opening 43a of the slot 43.

[0066] As described above, in the stator 2, the foam layer 52 may be located on one surface in the thickness direction of at least a portion of each of the pair of protrusions 512. Therefore, in the preparation step of the manufacturing method of the stator 2, as shown in Figure 16, an insulating sheet 8 may be prepared in which the foaming agent 9 is placed on one surface in the thickness direction of at least a portion of the pair of protrusions 512 of the insulating sheet 8.

[0067] In other words, the method for manufacturing the stator 2 includes a preparation step, an insulating sheet insertion step, a coil insertion step, and an insulating member formation step.

[0068] The preparation step involves preparing an insulating sheet 8, which, when inserted into the slot 43, has a pair of protrusions 512 that protrude in the axial direction A of the stator core 4 from axial openings 43a that open in one axial direction and the other axial direction of the slot 43, respectively, and a foaming agent 9 that expands when heated is placed on one surface in the thickness direction of at least a portion of each of the pair of protrusions 512.

[0069] The insulating sheet insertion step involves inserting the insulating sheet 8 into the slot 43. The coil insertion step involves inserting the coil portion 6 into the insulating sheet 8. In the insulating member forming step, with the insulating sheet 8 and coil portion 6 inserted into the slot 43, the insulating sheet 8 is heated to foam the foaming agent 9, thereby forming an insulating member 5 in which the thickness of a portion of the foamed layer 52 located in the protruding portion 512 is greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6 in the axial opening 43a.

[0070] This manufacturing method makes it possible to obtain an insulating member 5 in which at least a portion of the area where the foamed layer 52 is located in the protruding portion 512 is larger than the distance between the inner surface of the slot 43 in the axial opening 43a and the outer surface of the coil portion 6. As a result, it is possible to obtain a stator 2 in which movement of the insulating member 5 relative to the slot 43 is suppressed.

[0071] Furthermore, the expanded foam layer 52 pushes the outer surface of the coil portion 6 inward into the slot 43. This makes it possible to obtain a stator 2 in which the movement of the coil portion 6 relative to the insulating member 5 is suppressed. Thus, this manufacturing method allows for the production of a stator 2 in which the movement of the coil portion 6 relative to the slot 43 is suppressed through a simple process.

[0072] Furthermore, the manufacturing method of this embodiment further comprises a bending step and a notch formation step. In the bending step, the rectangular insulating sheet 8 is bent at a position where it is located at the corner of the slot 43, thereby forming a corner portion 51e extending in the axial direction A on the insulating sheet 8, and overlapping the first end portion 51c and the second end portion 51d in the thickness direction. In the notch formation step, in the protruding portion 512, a notch portion 513 extending in the axial direction A is formed at the corner portion 51e of the first end portion 51c, which is located on the outside of the first end portion 51c and the second end portion 51d, and is closest to the tip in the circumferential direction W of the insulating member.

[0073] This allows the region between the tip of the first end 51c of the protruding portion 512 in the circumferential direction W of the insulating member and the notched portion 513 to be moved to a position outside the slot 43 when viewed in the axial direction A. Therefore, the foamed layer 52 can be easily expanded. Thus, this manufacturing method allows for the production of a stator 2 in which the movement of the coil portion 6 relative to the slot 43 is suppressed, through a simple process.

[0074] (Embodiment 2) Next, with reference to Figure 17, the stator 102 of the motor according to Embodiment 2 will be described. In this embodiment, the configuration of the insulating member 105 is different from the configuration of the insulating member 5 in Embodiment 1. In the following, the same configuration as in Embodiment 1 will be omitted from the description, and only the configuration that differs from Embodiment 1 will be described.

[0075] As shown in Figure 17, the insulating member 105 of the stator 102 has a base layer 151 and a foamed layer 152. In this embodiment, the other surface 151b in the thickness direction of the base layer 151 is located on the inside. That is, in this embodiment, the foamed layer 152 is located on the outer surface side of the base layer 151.

[0076] Furthermore, in this embodiment, the foam layer 152 is located on a part of the pair of protrusions 512 of the base layer 151. That is, the foam layer 152 is located on one surface 151a in the thickness direction of a part of the protrusion 512. Therefore, a part of the portion of the insulating member 105 where the protrusion 512 is located has a thickness greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6. Thus, even with this configuration, movement of the insulating member 105 relative to the slot 43 can be suppressed.

[0077] Furthermore, in this embodiment, at least a portion of the foamed layer 152 located on the protrusion 512 is in contact with the axial end face of the stator core 4. This prevents the insulating member 105 from moving in one axial direction and the other axial direction relative to the slot 43.

[0078] (Embodiment 3) Next, with reference to Figure 18, the stator 202 of the motor according to Embodiment 3 will be described. In this embodiment, the configuration of the insulating member 205 is different from the configuration of the insulating member 5 in Embodiment 1. In the following, the same configuration as in Embodiment 1 will be omitted from the description, and only the configuration that differs from Embodiment 1 will be described.

[0079] As shown in Figure 18, the insulating member 205 of the stator 202 has a base layer 251 and a foamed layer 252. In this embodiment, a pair of protrusions 512 of the base layer 251 are bent outward from the slot 43 when viewed in the axial direction A. Therefore, in this embodiment as well, at least a portion of the foamed layer 252 located on one surface 251a in the thickness direction of the protrusion 512 is in contact with the axial end face of the stator core 4. This prevents the insulating member 205 from moving in one axial direction and the other axial direction relative to the slot 43.

[0080] (Other Embodiments) Although embodiments of the present invention have been described above, the embodiments described above are merely examples for carrying out the present invention. Therefore, the invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.

[0081] In each of the above embodiments, the motor 100 is an inner rotor type motor in which the rotor 3 is located radially inward of the stator 2. However, the motor may also be an outer rotor type motor in which the rotor is located radially outward of the stator.

[0082] In the above embodiment 1, the first end 51c and the second end 51d of the insulating member 5 overlap in the thickness direction. However, the first end and the second end of the insulating member do not have to overlap.

[0083] Figure 19 shows an example of a configuration in which the first end 351c and the second end 351d of the insulating member 305 do not overlap. In the example shown in Figure 19, the insulating member 305 of the stator 302 has a base layer 351 and a foam layer 352, and the base layer 351 has a first end 351c and a second end 351d located at one end and the other end, respectively, in the circumferential direction W of the insulating member. The first end 351c and the second end 351d of the insulating member 305 do not overlap. In Figure 19, the first end and the other end of the insulating member 305 in the circumferential direction W are separated, but the two ends may be in contact. Also, in Figure 19, the first end 351c and the second end 351d of the insulating member 305 are located on the radial opening 43b side, but the first end and the second end of the insulating member may be located on the bottom surface side of the slot, or at other positions.

[0084] In the above embodiment 1, the insulating member 5 is also arranged on the radial opening 43b side of the slot 43. However, the insulating member does not have to be arranged on the radial opening side of the slot. For example, as shown in Figure 19, the insulating member 305 of the stator 302 may have an opening on the radially inward side.

[0085] In the first embodiment described above, the first end 51c and the second end 51d of the insulating member 5 overlap in the thickness direction, and the protruding portion 512 has a notch at the corner 51e of the first end 51c located on the outside, which is closest to the tip in the circumferential direction W of the insulating member. However, the first end and the second end of the insulating member do not overlap, and the protruding portion may have a notch at the corner of either the first end or the second end that is closest to the tip in the circumferential direction W of the insulating member. The protruding portion may also have notches at the corners of the first end and the second end that are closest to the respective tips.

[0086] In the first embodiment described above, the protruding portion 512 has a notch 513 at the corner 51e closest to the tip of the first end portion 51c in the circumferential direction W of the insulating member. However, the protruding portion may also have a notch in the region between the tip of the first end portion in the circumferential direction W of the insulating member and the corner closest to the tip. The protruding portion may also have notches in the region between the tip of the first end portion and the corner closest to the tip of each of the first and second ends.

[0087] In other words, the insulating member has a corner portion located between a portion extending radially along the inner surface of the slot and a portion extending circumferentially along the bottom surface of the slot, and the protruding portion may have the notch portion in the region between the tip of either the first end located at one end in the direction extending along the outer circumference of the coil portion when viewed in the axial direction A of the base layer and the corner portion closest to the tip, or in the corner portion. In this case, the foamed layer only needs to be located on one surface in the thickness direction between the tip of the protruding portion and the notch portion.

[0088] This allows the region between the tip of one end of the protruding portion that extends along the outer circumference of the coil portion in the axial direction and the notched portion to be moved to a position outside the slot in the axial direction. Therefore, the foamed layer can be easily expanded. Consequently, an insulating member can be easily obtained in which a portion of the insulating member that protrudes from the end face in the axial direction A of the stator core has a thickness greater than the distance between the inner surface of the slot and the outer surface of the coil portion.

[0089] For example, as shown in Figure 19, the protruding portion 512 of the insulating member 305 has a notch 513 in the region between the tip of the first end 351c in the circumferential direction W of the insulating member and the corner 351e closest to the tip. Also, the protruding portion 512 of the insulating member 305 has a notch 513 in the region between the tip of the second end 351d in the circumferential direction W of the insulating member and the corner 351e closest to the tip.

[0090] In an insulating member 305 with this configuration, the thickness of a portion of the portion where the foam layer 352 is located at the protruding portion 512 is greater than the distance between the inner surface of the slot 43 and the outer surface of the coil portion 6 at the axial opening 43a of the slot 43. Therefore, even with this configuration, it is possible to suppress the insulating member 305 from moving axially A relative to the slot 43.

[0091] In the embodiment 1 described above, the protruding portion 512 has a notch 513 extending in the axial direction A at the corner portion 51e. However, the protruding portion may have a notch extending in the axial direction at a position other than the corner portion. In this case, the foamed layer may be located at least on one of the surfaces of the protruding portion in the thickness direction, on either one side or the other side of the insulating member circumferential direction W with respect to the notch portion.

[0092] This configuration also allows a region located on at least one side of the notch in the protruding portion to be moved to a position outside the slot when viewed in the axial direction.

[0093] In the above embodiment 1, each of the pair of protrusions 512 has a notch 513. However, the pair of protrusions do not have to have a notch. One of the pair of protrusions may have a notch.

[0094] In the above embodiment 1, the first end 51c and the second end 51d of the insulating member 5 overlap in the thickness direction on the bottom surface side of the slot 43. However, the first end and the second end of the insulating member may overlap in the thickness direction on the side extending in the radial direction R of the slot, or on the radial opening side.

[0095] In the first embodiment described above, the portion of the foamed layer 52 outside the slot 522 located on one surface 51a in the thickness direction of the second end 51d has the same thickness as the foamed layer 521 inside the slot. However, a portion of the portion located on one surface in the thickness direction of the second end may have a greater thickness than the foamed layer inside the slot. This can improve the effect of suppressing the movement of the insulating member relative to the slot.

[0096] In the first embodiment described above, the inner surface of the slot 43 in the insulating member 5 is planar. However, the insulating member may have irregularities on the inner surface of the slot.

[0097] This increases the frictional force when the insulating member moves relative to the inner surface of the slot. Therefore, the movement of the insulating member relative to the slot can be further suppressed.

[0098] The method for manufacturing the stator 2 in the first embodiment includes a bending step. However, the method for manufacturing the stator does not have to include a bending step. That is, the insulating sheet may be formed in an annular shape when viewed in the axial direction A.

[0099] The method for manufacturing the stator 2 in the first embodiment includes a notch formation step. However, the method for manufacturing the stator does not necessarily have to include a notch formation step.

[0100] In the first embodiment, the notch forming step forms a notch 513 extending in the axial direction A at the corner 51e closest to the tip of the first end 51c, which is located on the outside of the first end 51c and the second end 51d, in the protruding portion 512. However, the notch forming step may form a notch extending in the axial direction in the region between the tip of either the first end located at one end of the insulating member in the circumferential direction W of the insulating member and the second end located at the other end, and the corner closest to the tip, or at the corner. In this case, the preparation step may prepare an insulating sheet in which the foaming agent is placed on at least one surface in the thickness direction between the tip of the protruding portion in the circumferential direction W of the insulating member and the portion in which the notch is formed. The insulating member forming step may move the region between the tip of the protruding portion and the notch to a position outside the slot when viewed in the axial direction by foaming the foaming agent.

[0101] This allows the region between one end of the protrusion and the notch to be moved axially outward from the slot in accordance with the increase in volume due to the foaming of the foaming agent. This makes it possible to realize a stator in which the insulating member is prevented from moving axially relative to the slot.

[0102] In the first embodiment described above, the notch formation step forms a notch 513 in the insulating sheet 8 that has been folded by the bending step. However, the notch formation step may also form a notch in the insulating sheet before it is folded. The notch formation step may also form a notch in the insulating sheet that has been inserted into the slot by the insulating sheet insertion step.

[0103] (Example Configuration) This technology can also be configured as follows:

[0104] (1) The stator is a stator having a cylindrical core back portion extending in the axial direction, a plurality of teeth portions extending radially from the core back portion and arranged in the circumferential direction, and a plurality of slots arranged in the circumferential direction between adjacent teeth portions in the circumferential direction, an insulating member disposed on the inner surface of the plurality of slots, and a coil portion disposed inside the insulating member within the plurality of slots. The insulating member has a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer located on one surface of the base material layer in the thickness direction, in an expanded state due to heating. The base material layer has a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively. The foamed layer is located on one surface in the thickness direction of at least a part of each of the pair of protrusions. Of the insulating member, the thickness of a part of the portion of the protrusion where the foamed layer is located is greater than the distance between the inner surface of the slot and the outer surface of the coil portion in the slot opening.

[0105] (2) In the stator described in (1), the foam layer is located on the surface of the base material layer on the coil side.

[0106] (3) In the stator described in (1) or (2), the protrusion has a notch that extends in the axial direction. The foam layer is located on at least one of the surfaces of the protrusion in the thickness direction, on either the side or the other side of the notch that extends along the outer circumference of the coil portion when viewed in the axial direction.

[0107] (4) In the stator described in (3), the insulating member has a corner portion located between a portion extending radially along the inner surface of the slot and a portion extending circumferentially along the bottom surface of the slot. The protruding portion has the notch portion in the base material layer in the region between the tip of either the first end located at one end in the direction extending along the outer circumference of the coil portion when viewed in the axial direction and the corner portion closest to the tip, or in the corner portion. The foamed layer is located at least on the plane in the thickness direction between the tip of the protruding portion and the notch portion.

[0108] (5) In the stator described in (4), the other of the first end and the second end of the protruding portion is located on the coil portion side with respect to the region between the tip of one of the protruding portions and the notched portion, and overlaps with the region in the thickness direction.

[0109] (6) In the stator described in (4) or (5), the region between the one tip of the protrusion and the notch is located on the bottom side of the slot when viewed in the axial direction.

[0110] (7) In the stator described in any one of (3) to (6), the pair of protrusions each have the notched portion.

[0111] (8) In the stator described in any one of (1) to (7), the foam layer is located on the entire surface of the base layer on the coil side. The portion of the foam layer located within the slot is in contact with the coil, and the portion of the base layer located within the slot is in contact with the inner surface of the slot.

[0112] (9) In the stator described in any one of (1) to (8), the insulating member has irregularities on the inner surface of the slot.

[0113] In the stator described in any one of (10), (3) to (9), at least a portion of the foamed layer located on the protruding portion is in contact with the axial end face of the stator core.

[0114] (11) The motor comprises a stator as described in any one of (1) to (10), and a rotor arranged radially inward with respect to the stator.

[0115] (12) A method for manufacturing a stator is a stator core having a cylindrical core back portion extending in the axial direction and a plurality of teeth portions extending radially from the core back portion and arranged in the circumferential direction, wherein a plurality of slots arranged in the circumferential direction are formed between adjacent teeth portions in the circumferential direction, an insulating member disposed on the inner surface of the plurality of slots, and a coil portion disposed inside the insulating member within the plurality of slots, wherein the insulating member has a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer located on one surface in the thickness direction of the base material layer in an expanded state due to heating. A method for manufacturing a stator includes a preparation step of preparing an insulating sheet having a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively, when inserted into the slot, and on one surface in the thickness direction of at least a part of each of the pair of protrusions, a foaming agent that foams when heated is placed thereon; an insulating sheet insertion step of inserting the insulating sheet into the slot; a coil insertion step of inserting the coil part inside the insulating sheet; and an insulating member forming step of forming an insulating member by heating the insulating sheet to foam the foaming agent while the insulating sheet and the coil part are inserted into the slot, thereby forming an insulating member in which the thickness of a part of the portion where the foaming layer is located on the protrusion is greater than the distance between the inner surface of the slot and the outer surface of the coil part in the slot opening.

[0116] (13) The method for manufacturing a stator as described in (12) further comprises a bending step of forming an axially extending corner portion in the insulating sheet by bending the rectangular insulating sheet at a position where it is to be placed at the corner of the slot, and a notch forming step of forming an axially extending notch portion in the region between the tip of either the first end located at one end of the insulating sheet in a direction intersecting the axial direction and the second end located at the other end of the insulating sheet, or in the corner portion, at the protruding portion. In the preparation step, an insulating sheet is prepared in which the foaming agent is placed on at least one surface in the thickness direction between the tip of the protruding portion and the portion where the notch is formed. In the insulating member forming step, the foaming agent is foamed to move the region between the tip of the protruding portion and the notch portion to a position outside the slot when viewed in the axial direction.

[0117] In the method for manufacturing a stator described in (14)(13), the bending step is to form the corner portion in the insulating sheet and to overlap the first end and the second end in the thickness direction. In the notch forming step, an axially extending notch portion is formed in the protruding portion in the region between the tip of the outer end of the first end and the second end and the corner portion, or in the corner portion.

[0118] The present invention is applicable to a stator having a stator core in which a plurality of slots are formed between a plurality of teeth that fix a coil portion in a slot by an insulating member, an insulating member disposed on the inner surface of the plurality of slots, and a coil portion disposed inward of the insulating member within the plurality of slots.

[0119] 2, 102, 202, 302 Stator 3 Rotor 4 Stator core 5, 105, 205, 305 Insulating member 6 Coil section 6a Conductor 8 Insulating sheet 9 Foaming agent 41 Core back section 42 Teeth section 43 Slot 43a Axial opening (slot opening) 43b Radial opening 51, 151, 251, 351 Base layer 51a, 151a, 251a One side in the thickness direction 51b, 151b The other side in the thickness direction 51c, 351c First end 51d, 351d Second end 51e, 351e Corner 52, 152, 252, 352 Foam layer 100 Motor 511 Slot arrangement section 512 Protruding section 513 Notch 521 Foam layer inside slot 522 Foam layer outside slot W Insulating member circumferential direction (direction extending along the outer circumference of the coil when viewed in the axial direction)

Claims

1. A stator having a stator core having a cylindrical core back portion extending in the axial direction and a plurality of teeth portions extending radially from the core back portion and arranged in the circumferential direction, wherein a plurality of slots arranged in the circumferential direction are formed between adjacent teeth portions in the circumferential direction; an insulating member disposed on the inner surface of the plurality of slots; and a coil portion disposed inside the insulating member within the plurality of slots, wherein the insulating member has a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer located on one surface in the thickness direction of the base material layer in an expanded state due to heating; the base material layer has a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively; the foamed layer is located on one surface in the thickness direction of at least a part of each of the pair of protrusions; and the thickness of a part of the portion of the insulating member where the foamed layer is located at the protrusion is greater than the distance between the inner surface of the slot and the outer surface of the coil portion at the slot opening.

2. A stator according to claim 1, wherein the foamed layer is located on the surface of the base material layer on the coil portion side.

3. A stator according to claim 1, wherein the protrusion has a notch extending in the axial direction, and the foam layer is located on at least one of the two sides of one of the surfaces of the protrusion in the thickness direction, in a direction extending along the outer circumference of the coil portion when viewed in the axial direction with respect to the notch.

4. A stator according to claim 3, wherein the insulating member has a corner portion located between a portion extending radially along the inner surface of the slot and a portion extending circumferentially along the bottom surface of the slot, the protruding portion has the notch portion in the region between the tip of either a first end located at one end in the direction extending along the outer circumference of the coil portion when viewed in the axial direction and the corner portion closest to the tip, or in the corner portion, and the foamed layer is located on at least one surface in the thickness direction between the tip of the protruding portion and the notch portion.

5. A stator according to claim 4, wherein the other of the first end and the second end of the protruding portion is located on the coil portion side with respect to the region between the one tip and the notch and overlaps with the region in the thickness direction.

6. A stator according to claim 4, wherein the region between the one tip of the protrusion and the notch is located on the bottom side of the slot when viewed in the axial direction.

7. A stator according to claim 3, wherein each of the pair of protrusions has the notched portion.

8. A stator according to claim 1, wherein the foam layer is located on the entire surface of the base material layer on the coil side, the portion of the foam layer located within the slot is in contact with the coil, and the portion of the base material layer located within the slot is in contact with the inner surface of the slot.

9. A stator according to claim 1, wherein the insulating member has irregularities on the inner surface side of the slot.

10. A stator according to claim 3, wherein at least a portion of the foamed layer located on the protruding portion is in contact with the axial end face of the stator core.

11. A motor having a stator according to any one of claims 1 to 10, and a rotor arranged radially inward with respect to the stator.

12. A method for manufacturing a stator, comprising: a stator core having a cylindrical core back portion extending in the axial direction, a plurality of teeth portions extending radially from the core back portion and arranged circumferentially, wherein a plurality of slots arranged circumferentially are formed between adjacent teeth portions in the circumferential direction; an insulating member disposed on the inner surface of the plurality of slots; and a coil portion disposed inside the insulating member within the plurality of slots, wherein the insulating member comprises a base material layer extending along the outer circumference of the coil portion when viewed in the axial direction, and a foamed layer positioned on one surface in the thickness direction of the base material layer in an expanded state due to heating, the method comprising: a preparation step of preparing an insulating sheet having a pair of protrusions that protrude in the axial direction of the stator core from slot openings that open in one axial direction and the other axial direction of the slot, respectively when inserted into the slot, and a foaming agent that foams when heated is disposed on one surface in the thickness direction of at least a part of each of the pair of protrusions; an insulating sheet insertion step of inserting the insulating sheet into the slot; and a coil insertion step of inserting the coil portion inside the insulating sheet. A method for manufacturing a stator, comprising: an insulating member forming step, in which the insulating sheet and the coil portion are inserted into the slot, the insulating sheet is heated to foam the foaming agent to form the foamed layer, and the thickness of a portion of the portion where the foamed layer is located in the protruding portion is greater than the distance between the inner surface of the slot and the outer surface of the coil portion in the slot opening to form the insulating member.

13. A method for manufacturing a stator according to claim 12, further comprising: a bending step of bending the rectangular insulating sheet at a position where it is to be placed at the corner of the slot to form an axially extending corner portion on the insulating sheet; and a notch forming step of forming an axially extending notch portion on the protruding portion in the region between the tip of either the first end located at one end of the insulating sheet in a direction intersecting the axial direction and the second end located at the other end and the corner portion closest to the tip, or on the corner portion, wherein the preparation step prepares an insulating sheet on which the foaming agent is placed at least on one surface in the thickness direction between the tip of the protruding portion and the portion where the notch portion is formed, and the insulating member forming step moves the region between the tip of the protruding portion and the notch portion to a position outside the slot when viewed in the axial direction.

14. A method for manufacturing a stator according to claim 13, wherein in the bending step, the corner portion is formed in the insulating sheet and the first end and the second end are overlapped in the thickness direction, and in the notch portion forming step, a notch portion extending in the axial direction is formed in the protruding portion in the region between the tip of the outer end of the first end and the second end and the corner portion, or in the corner portion.

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