Stator, motor, and method for manufacturing stator

Abstract

This stator includes a stator core that has a plurality of teeth portions and is configured such that a plurality of slots are arranged in the circumferential direction between the teeth portions adjacent to each other in the circumferential direction among the plurality of teeth portions, a plurality of coils located in the plurality of slots, and a bus bar that electrically connects the coils of the same phase among the plurality of coils, wherein: each of the plurality of coils includes an annular portion around which a conductive wire is wound, and a pair of lead portions that are located at the outermost periphery of the annular portion, are located at different circumferential positions with respect to the annular portion in the coils adjacent to each other in the circumferential direction, and extend to the outside of the slots toward the bus bar; the coils adjacent to each other in the circumferential direction among the plurality of coils are electrically connected to constitute a coil group; and in the coil groups, the coils adjacent to each other in the circumferential direction are joined to each other at the lead portions, and the lead portions located at the circumferential ends in the coils located at both ends in the circumferential direction are electrically connected to the bus bar.

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. 2025-014447 filed in Japan on January 31, 2025, the content of which is incorporated herein by reference.

[0002] There is known a stator in which coils are respectively positioned in a plurality of slots of a stator core. As such a stator, for example, Patent Document 1 discloses a stator including a cylindrical yoke, a stator core having a plurality of teeth arranged at intervals in the circumferential direction on the inner peripheral side of the yoke, a plurality of coils wound around the teeth via an insulator, and a bus bar ring.

[0003] In the stator of Patent Document 1, the connection terminals of the bus bar ring are welded to the coil ends and are electrically connected to the coils.

[0004] Japanese Patent Application Laid-Open No. 2024-166767

[0005] By the way, when welding the coil ends to the bus bar as in the stator of Patent Document 1, it is necessary to perform welding operations at a plurality of welding points in order to weld a plurality of coil ends to the bus bar. Therefore, there is a need for a stator configuration that can improve productivity by reducing the locations where welding operations are performed compared to the conventional configuration.

[0006] An object of the present invention is to realize a stator configuration that can improve productivity by reducing the welding points between the coil and the bus bar compared to the conventional configuration.

[0007] A stator according to an exemplary embodiment of the present invention comprises a stator core having an annular core back portion centered on an axis, and a plurality of teeth portions that protrude axially or radially from the core back portion and are arranged circumferentially, with a plurality of slots arranged circumferentially between adjacent teeth portions in the plurality of teeth portions, a plurality of coils located within the plurality of slots, and a busbar that electrically connects coils of the same phase among the plurality of coils. Each of the plurality of coils has an annular portion around which a conductor is wound, and a pair of lead portions located on the outermost periphery of the annular portion, with adjacent coils in the circumferential direction having different circumferential positions relative to the annular portion and extending outward toward the busbar and the slot. Adjacent coils in the circumferential direction are electrically connected to each other to form a coil group. In the coil group, adjacent coils in the circumferential direction are joined to each other by their lead portions, and the lead portions located at the circumferential ends of the coils at both ends in the circumferential direction are electrically connected to the busbar.

[0008] A motor according to an exemplary embodiment of the present invention comprises a stator having the above-described configuration and a rotor that rotates relative to the stator about the axis of the stator.

[0009] 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 an annular core back portion centered on an axis, a plurality of teeth portions protruding axially or 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; a plurality of coils located within the plurality of slots; and busbars that electrically connect coils of the same phase among the plurality of coils. The manufacturing method includes: a coil forming step of forming multiple types of coils by winding a wire, each having an annular portion and a pair of lead portions extending outward from the outermost periphery of the annular portion to the slot, and each having different circumferential positions of the pair of lead portions relative to the annular portion; a coil group forming step of forming a coil group by arranging the coils formed in the coil forming step, each having different circumferential positions of the pair of lead portions, in the circumferential direction, and electrically connecting the lead portions of adjacent coils in the circumferential direction; a coil group insertion step of inserting the coil group into the slot of the stator core; and a busbar connection step of electrically connecting the lead portions located at the circumferential ends of the coils located at both ends of the coil group to the busbar.

[0010] According to the present invention, it is possible to realize a stator configuration that can improve productivity by reducing the number of welding points between the coil and the busbar.

[0011] Figure 1 is a cross-sectional view showing an example of a schematic configuration of a motor. Figure 2 is a perspective view showing an example of a schematic configuration of a stator. Figure 3 is a perspective view showing an example of a schematic configuration of a stator core and coils. Figure 4 is a perspective view showing an example of a schematic configuration of a coil. Figure 5 is a top view showing an example of a schematic configuration of a coil. Figure 6 is a schematic diagram for explaining the coil formation process and the coil group formation process. Figure 7 is a schematic diagram for explaining the coil group insertion process. Figure 8 is a top view for explaining the busbar connection process. Figure 9 is a top view showing a schematic configuration of a coil according to another embodiment. Figure 10 is a perspective view showing a schematic configuration of a stator coil located on one side in the axial direction relative to the rotor. Figure 11 is a diagram showing an example of the configuration of a coil group having two coils.

[0012] 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.

[0013] In the following description, the direction in which the axis P of the motor 100, rotor 50, and stator 1 extends is referred to as "axial direction A". The circumferential direction centered on axis P is referred to as "circumferential direction C", and the radial direction centered on axis P is referred to as "radial direction B". Furthermore, the direction described as "one axial direction" in the specification is indicated as "A1" in the figures, and the direction described as "the other axial direction" is indicated as "A2" in the figures. In addition, the direction described as "radially outward" in the specification is indicated as "B1" in the figures, and the direction described as "radially inward" is indicated as "B2" in the figures. Note that the directions shown in the figures are defined solely for the convenience of explanation and do not limit the orientation of the motor during use or assembly according to the present invention.

[0014] 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.

[0015] (Motor) Figure 1 is a cross-sectional view showing an example of the schematic configuration of the motor 100. Referring to Figure 1, the motor 100 is, for example, an axial gap type motor having a gap between the rotor 50 and the stator 1 in the axial direction A. The motor 100 has a rotor 50 and stators 1 located on both sides A1 and A2 of the axial direction A of the rotor 50. Thus, the motor 100 is a DSSR (Double Stator Single Rotor) type motor. The stators 1 located on both sides A1 and A2 of the axial direction A of the rotor 50 have the same shape as each other except that the direction of the axial direction A is opposite and the shape of the coils. Therefore, below, the stator 1 located on the other side A2 of the axial direction A of the rotor 50 will be described.

[0016] (Stator) Figure 2 is a perspective view showing an example of the schematic configuration of the stator 1. Figure 3 is a perspective view showing an example of the schematic configuration of the stator core 10 and coil 20. Referring to Figures 1 to 3, the stator 1 has a stator core 10, a plurality of coils 20, and a plurality of busbars 30. In Figure 2, reference numeral 26 denotes an annular umbrella portion for preventing the coil 20 from coming out of the teeth portion 12 of the stator core 10 (described later) in the axial direction A.

[0017] The stator core 10 is a magnetic material. The stator core 10 has, for example, electromagnetic steel sheets stacked in the radial direction B. In the stator core 10, a single strip of steel sheet constituting the electromagnetic steel sheet is wound around an axis P and stacked in the radial direction B.

[0018] The stator core 10 has a core back portion 11 and a plurality of teeth portions 12.

[0019] The core back portion 11 is annular in shape with axis P as its center. When viewed in the axial direction A, the inner or outer circumferential edge of the core back portion 11 is circular. When viewed in the axial direction A, the inner or outer circumferential edge of the core back portion 11 may be polygonal. The core back portion 11 has a plurality of grooves 111 that are recessed in the axial direction A and extend from the inside to the outside in the radial direction B of the core back portion 11.

[0020] Multiple teeth portions 12 protrude in the axial direction A from one surface A1 in the axial direction A of the core back portion 11. Multiple teeth portions 12 are arranged in the circumferential direction C.

[0021] Multiple slots SL are arranged in the circumferential direction C between adjacent teeth 12 in the circumferential direction C. The circumferential width of the teeth 12 is larger when viewed in the axial direction A, from the inside of the radial direction B to the radially outer end, and increases towards the radially outer B1.

[0022] Multiple coils 20 are located within multiple slots SL. A coil 20 is a cylindrical member obtained by winding a wire. More specifically, a coil 20 has an annular portion 21 and a pair of lead portions 22.

[0023] The annular portion 21 is cylindrical in shape around which the conductor is wound. The annular portion 21 has a trapezoidal outer shape in which the circumferential width increases towards the radially outward B1 when viewed in the axial direction A. The axial length A of the annular portion 21 is the same as the axial length A of the teeth portion 12 of the stator core 10. The teeth portion 12 of the stator core 10 is inserted into the annular portion 21. The pair of lead portions 22 are both ends of the conductor and extend radially inward B2 from the outermost circumference of the annular portion 21. In this embodiment, the pair of lead portions 22 are of the same length.

[0024] The multiple coils 20 include several types of coils, each with a different winding method for the conductor and a different position of the pair of lead portions 22 relative to the annular portion 21. Figure 4 is a perspective view showing an example of the schematic configuration of the coil 20. Figure 5 is a top view showing an example of the schematic configuration of the coil 20. In this embodiment, the multiple coils 20 include two types of coils: a first coil 20A and a second coil 20B.

[0025] In the following explanation, if it is not necessary to distinguish between coils, they will simply be referred to as coil 20, and if it is necessary to distinguish between coils, they will be referred to as the first coil 20A or the second coil 20B. Similarly, in the following explanation, if it is not necessary to distinguish between annular sections for each coil, they will simply be referred to as annular section 21, and if it is necessary to distinguish between annular sections for each coil, they will be referred to as the first annular section 21A or the second annular section 21B. Furthermore, in the following explanation, if it is not necessary to distinguish between lead sections for each coil, they will simply be referred to as lead section 22, and if it is necessary to distinguish between lead sections for each coil, they will be referred to as the first lead section 22A or the second lead section 22B.

[0026] In the first coil 20A, the pair of first lead portions 22A are located in a position that overlaps with the first annular portion 21A when viewed in the direction in which the first lead portions 22A extend. The pair of first lead portions 22A are located at one A1 in the axial direction A of the first annular portion 21A of the first coil 20A. The pair of first lead portions 22A do not intersect each other when viewed in the axial direction A. In the second coil 20B, the tip portions of the pair of second lead portions 22B are located circumferentially outward from the second annular portion 21B when viewed in the direction in which the second lead portions 22B extend. The pair of second lead portions 22B are located at one A1 in the axial direction A of the second annular portion 21B of the second coil 20B. The pair of second lead portions 22B intersect each other when viewed in the axial direction A.

[0027] The first coil 20A and the second coil 20B are aligned in the circumferential direction C and connected to each other by the first lead portion 22A and the second lead portion 22B, respectively, to form a coil group Q. In the coil group Q, the first coil 20A, the second coil 20B, and the first coil 20A are aligned sequentially in the circumferential direction C and connected to each other by the first lead portion 22A and the second lead portion 22B. Specifically, of the pair of first lead portions 22A in the first coil 20A, the first lead portion 22A not located at the end in the circumferential direction C is welded to the second lead portion 22B of the second coil 20B. In this way, in the coil group Q, the first coil 20A, the second coil 20B, and the first coil 20A are connected and integrated while aligned in the circumferential direction C. The coil group Q is molded with resin. That is, a resin layer 25 is located on the outer surface of each coil 20A, 20B of the coil group Q.

[0028] Furthermore, of the pair of first lead portions 22A in the first coil 20A, the first lead portion 22A located at the circumferential end C is not connected to any other coil. Also, the first lead portion 22A and the second lead portion 22B, which are joined to each other, are located at the same position in the axial direction A with respect to the first annular portion 21A and the second annular portion 21A.

[0029] With the above configuration, in coil group Q, the first coil 20A is located at both ends in the circumferential direction C, and the second coil 20B is located in the center. That is, when coil group Q is composed of an odd number of coils 20, the first coils 20A located at both ends in the circumferential direction C in coil group Q have the same configuration. This reduces the number of types of coils 20 that make up coil group Q. Therefore, coils 20 can be produced efficiently. Consequently, the production efficiency of stator 1 can be improved.

[0030] In this embodiment, the first coils 20A located at both ends in the circumferential direction C in the coil group Q are positioned such that, when viewed in the direction in which their first lead portions 22A extend, a pair of first lead portions 22A overlap with the first annular portion 21A of the first coil 20A. The second coils 20B located adjacent to the first coils 20A and circumferential direction C in the coil group Q are positioned such that, when viewed in the direction in which their second lead portions 22B extend, the tips of a pair of second lead portions 22B are positioned circumferentially outward from the second annular portion 21B of the second coil 20B.

[0031] As a result, in the coil group Q, the first coil 20A located at both ends in the circumferential direction C and the second coil 20B adjacent to it in the circumferential direction C have their first lead portions 22A and second lead portions 22B positioned close to the circumferential direction C, allowing for easy connection of the first lead portion 22A and second lead portion 22B. Therefore, the production efficiency of the stator 1 can be improved.

[0032] Each of the coils 20 has multiple coil groups Q as described above. Therefore, by inserting the multiple coil groups Q into the slot SL of the stator core 10, a coil 20 wound around the teeth portion 12 of the stator core 10 is obtained.

[0033] The multiple busbars 30 are located radially inward B2 relative to the stator core 10. The multiple busbars 30 electrically connect the coils 20 of the same phase to each other, and also electrically connect the coils 20 to terminals (not shown). The multiple busbars 30 include a first busbar 30A that electrically connects the coils 20 in the circumferential direction C, and a second busbar 30B that electrically connects the coils 20 to the terminals. In Figures 2 and 3, reference numeral 35 denotes a terminal connection portion of the second busbar 30B that is connected to the terminals.

[0034] Each of the multiple busbars 30 is a flat plate-shaped member made of a conductive material. The multiple busbars 30 are positioned radially inward B2 relative to the stator core 10, with their thickness direction coinciding with the axial direction A.

[0035] The busbar 30 has a busbar body portion 31 and a lead connection portion 32. The busbar body portion 31 extends in an arc shape in the circumferential direction C when viewed in the axial direction A. The lead connection portion 32 protrudes from the radial outer circumference of the busbar body portion 31 in one direction A1 in the axial direction A, which is the direction in which the teeth portion 12 protrudes.

[0036] The lead connection portion 32 is located radially inward B2 relative to the first lead portion 22A located at the circumferential end of the first coil 20A in each coil group Q, when multiple coil groups Q are inserted into the slot SL of the stator core 10. The tip of the busbar body portion 31 is located radially inward B2 relative to the first lead portion 22A. This allows the first lead portion 22A of the first coil 20A in each coil group Q to be connected to the lead connection portion 32.

[0037] In each coil group Q, the pair of first lead portions 22A of the first coil 20A and the pair of second lead portions 22B of the second coil 20B are located on the side away from the busbar body 31 in the first coil 20A and the second coil 20B.

[0038] In other words, the busbar 30 has a busbar body portion 31 extending in the circumferential direction C, and a lead connection portion 32 extending from the busbar body portion 31 in the direction of the protrusion of the teeth portion 12, to which the first lead portions 22A of the first coil 20A located at both ends in the circumferential direction C in the coil group Q are connected. The pair of lead portions 22 are located on the side of the coil 20 that is away from the busbar body portion 31 in the direction of the protrusion.

[0039] As a result, the lead portion 22 is positioned at a distance from the busbar body portion 31, which extends in the circumferential direction C, in the direction of the protrusion of the teeth portion 12, thereby ensuring an electrical insulation distance between the lead portion 22 and the busbar body portion 31.

[0040] Furthermore, because the lead portion 22 is positioned at a distance from the busbar body portion 31 in the protruding direction, the lead portion 22 can be easily connected to the lead connection portion 32 that extends from the busbar body portion 31 in the protruding direction. Therefore, the ease of connecting the lead portion 22 to the busbar 30 can be improved. Consequently, the production efficiency of the stator 1 can be improved.

[0041] The lead connection portion 32 has a recess 32a at its tip into which the first lead portion 22A of the first coil 20A is inserted. This allows the first lead portion 22A of the first coil 20A to be positioned relative to the tip of the lead connection portion 32.

[0042] In this embodiment, the stator 1 has an annular core back portion 11 centered on an axis P, and a plurality of teeth portions 12 protruding axially A from the core back portion 11 and arranged in the circumferential direction C, with a plurality of slots SL arranged in the circumferential direction C between adjacent teeth portions 12 in the circumferential direction C, and a plurality of coils 20 located within the plurality of slots SL, and a busbar 30 that electrically connects coils 20 of the same phase. Each of the plurality of coils 20 has an annular portion 21 around which a conductor is wound, and a pair of lead portions 22 located on the outermost periphery of the annular portion 21, with adjacent coils 20 in the circumferential direction C having different circumferential positions relative to the annular portion 21 and extending outward from the slot SL toward the busbar 30. The plurality of coils 20 adjacent to each other in the circumferential direction C are electrically connected to each other to form a coil group Q. In the coil group Q, adjacent coils 20 in the circumferential direction C are joined together by their lead portions 22, and the first lead portions 22A located at the circumferential ends of the first coils 20A located at both ends in the circumferential direction C are electrically connected to the busbar 30.

[0043] As a result, in the coil group Q, adjacent coils 20 in the circumferential direction C are not connected to the busbar 30, but rather the adjacent lead portions 22 of the coils 20 in the circumferential direction C are connected to each other, thereby reducing the number of connection points between the multiple coils 20 and the busbar 30.

[0044] Moreover, by connecting the lead portions 22 adjacent to each other in the circumferential direction C in the coils 20 adjacent to each other in the circumferential direction C, after forming the coil group Q, the coil group Q can be inserted into the slots SL of the stator core 10. Therefore, the plurality of coils 20 constituting the coil group Q can be inserted into the slots SL of the stator core 10 collectively. For this reason, compared with the case where the coils 20 are inserted into the respective slots SL of the stator core 10, the workability of assembling the coils 20 to the stator core 10 can be improved.

[0045] Also, before inserting the coil group Q into the slots SL of the stator core 10, the lead portions 22 of the coils 20 adjacent to each other in the circumferential direction C in the coil group Q are connected. Therefore, compared with the case where the coils 20 are inserted into the respective slots SL of the stator core 10 and then connected, the workability of connection can be improved.

[0046] Therefore, the stator 1 having the above-described configuration can improve the production efficiency.

[0047] Further, in the present embodiment, in the first coils 20A located at both ends in the circumferential direction C in the coil group Q, at least the first lead portion 22A located at the circumferential end is located at a position overlapping with the first annular portion 21A of the first coil 20A when viewed in the direction in which the first lead portion 22A extends. Thereby, it is possible to prevent the first lead portions 22A connected to the bus bar 30 from interfering with each other in the first coils 20A located at both circumferential ends in the coil groups Q adjacent to each other in the circumferential direction C. Therefore, while arranging the bus bar 30 compactly, the plurality of coil groups Q can be connected to the bus bar 30 without interfering with each other.

[0048] Also, in the present embodiment, the plurality of teeth portions 12 project from the core back portion 11 in the axial direction A and are arranged in the circumferential direction C. The pair of lead portions 22 extend from the outermost circumference of the coil 20 inward in the radial direction B2. The bus bar 30 is located inward in the radial direction B2 with respect to the plurality of coils 20.

[0049] As a result, the busbar 30 is located radially inward B2 relative to the multiple coils 20. Therefore, the first lead portion 22A located at the circumferential end of the first coil 20A, which is located at both ends of the coil group Q in the circumferential direction C, is electrically connected to the busbar 30 radially inward B2 relative to the multiple coils 20. In such cases, the workability when connecting the first lead portion 22A and the busbar 30 is not very good. However, by reducing the number of connection points between the lead portion 22 and the busbar 30 in the coil group Q, as in the configuration of this embodiment, the workability of the connection can be improved.

[0050] The motor 100 according to this embodiment includes a stator 1 having the above-described configuration and a rotor 50 that rotates around the axis P of the stator 1 relative to the stator 1. As described above, the stator 1 has a configuration that can improve production efficiency, and therefore the production efficiency of the motor 100 can be improved.

[0051] Furthermore, the stator 1 located at one A1 in the axial direction A relative to the rotor 50 and the stator 1 located at the other A2 in the axial direction A relative to the rotor 50 have the same coil winding direction when viewed in the axial direction A. Figure 10 is a perspective view showing the schematic configuration of the coil 1020 of the stator 1 located at one A1 in the axial direction A relative to the rotor 50. When the stator 1 is positioned facing the rotor 50 at one A1 in the axial direction A, and the stator 1 is positioned facing the rotor 50 at the other A2 in the axial direction A, the winding direction of the coil 1020 is the same as the winding direction of the coil 20 shown in Figure 4 when viewed in the axial direction A.

[0052] Furthermore, the shape of the coil leads differs between the stator 1 located at one A1 in the axial direction A relative to the rotor 50 and the stator 1 located at the other A2 in the axial direction A relative to the rotor 50, in order to match the shape of the busbar 30. That is, in order to ensure that current flows in the same direction through the coils 20 and 1020 of the two stators 1 when viewed in the axial direction A, the lead portion 1022 of the coil 1020 connected to the busbar 30 has a different shape from the lead portion 22 of the coil 20. Specifically, the first lead portion 1022A of the first coil 1020A intersects with each other when viewed in the axial direction A. The second lead portion 1022B of the second coil 1020B does not intersect with each other when viewed in the axial direction A. This makes it possible to match the shape of the busbar 30 between the stator 1 located at one A1 in the axial direction A relative to the rotor 50 and the stator 1 located at the other A2 in the axial direction A relative to the rotor 50. In Figure 10, reference numeral 1021 denotes the annular portion, reference numeral 1021A denotes the first annular portion, and reference numeral 1021B denotes the second annular portion.

[0053] (Method for Manufacturing a Stator) Next, a method for manufacturing the stator 1 having the above-described configuration will be explained using Figures 6 to 8. Figure 6 is a schematic diagram illustrating the coil formation process S1 and the coil group formation process S2. Figure 7 is a schematic diagram illustrating the coil group insertion process S3. Figure 8 is a top view illustrating the busbar connection process S4.

[0054] In the manufacturing method of the stator 1, first, a wire is wound to form a first coil 20A and a second coil 20B as shown in Figure 6. The process of forming the first coil 20A and the second coil 20B as shown in Figure 6 is called the coil formation process S1. Specifically, in this coil formation process S1, by winding a wire, the first coil 20A and the second coil 20B are formed, each having an annular portion 21 and a pair of lead portions 22 extending outward from the outermost circumference of the annular portion 21 to the slot SL, and the circumferential positions of the pair of lead portions 22 relative to the annular portion 21 are different.

[0055] In other words, in the coil formation step S1, a first coil 20A is formed in which the first lead portion 22A is positioned so that it overlaps with the first annular portion 21A when viewed in the direction in which the first lead portion 22A extends. Also in the coil formation step S1, a second coil 20B is formed in which the second lead portion 22B is positioned so that it overlaps with the second annular portion 21B when viewed in the direction in which the second lead portion 22B extends.

[0056] Next, as shown in Figure 6, with the formed first coil 20A and second coil 20B arranged in the circumferential direction C, the first lead portion 22A of the first coil 20A and the second lead portion 22B of the second coil 20B adjacent to each other in the circumferential direction C are electrically connected to form a coil group Q. This process of forming the coil group Q is the coil group formation process S2. Specifically, with the first coil 20A located at both ends in the circumferential direction C and the second coil 20B sandwiched between them, the first lead portion 22A of the first coil 20A and the second lead portion 22B of the second coil 20B are electrically connected by welding or the like to form the coil group Q. In this way, the second coil 20B is located adjacent to the first coil 20A in the circumferential direction C. In this embodiment, the coil group Q has two first coils 20A and one second coil 20B.

[0057] Although not specifically shown in the diagram, in the coil group formation step S2, the outer surface of the coil group Q is covered with resin. That is, in the coil group formation step S2, a resin layer 25 is formed on the outer surface of the coil group Q.

[0058] Subsequently, as shown in Figure 7, the coil group Q covered with the resin layer 25 is inserted into the slots SL of the stator core 10. The process of inserting the coil group Q into the slots SL of the stator core 10 is called the coil group insertion process S3. This coil group insertion process S3 is carried out until the coil group Q is inserted into all the slots SL of the stator core 10.

[0059] Then, as shown in Figure 8, the lead portion 22 of the coil 20 inserted into the slot SL of the stator core 10 is connected to the lead connection portion 32 of the busbar 30 by welding or the like. The busbar connection step S4 is the step of connecting the lead portion 22 of the coil 20 to the lead connection portion 32 of the busbar 30.

[0060] The method for manufacturing the stator 1 according to this embodiment comprises a stator core 10 having an annular core back portion 11 centered on an axis P, and a plurality of teeth portions 12 protruding from the core back portion 11 in the axial direction A and arranged in the circumferential direction C, wherein a plurality of slots SL arranged in the circumferential direction C are formed between adjacent teeth portions 12 in the circumferential direction C, a plurality of coils 20 located within the plurality of slots SL, and busbars 30 that electrically connect coils 20 of the same phase among the plurality of coils 20. The manufacturing method includes: a coil forming step S1 in which a plurality of types of coils 20A, 20B are formed by winding a conductor, each having an annular portion 21 and a pair of lead portions 22 extending outward from the outermost periphery of the annular portion 21 to the outside of the slot SL, and the circumferential positions of the pair of lead portions 22 relative to the annular portion 21 are different; a coil group forming step S2 in which the coils 20A, 20B formed in the coil forming step S1, each having a pair of lead portions 22 with different circumferential positions, are arranged in the circumferential direction C, and the lead portions 22A, 22B of adjacent coils 20A, 20B in the circumferential direction C are electrically connected to form a coil group Q; a coil group insertion step S3 in which the coil group Q is inserted into the slot SL of the stator core 10; and a busbar connection step S4 in which the first lead portions 22A located at the circumferential ends of the first coils 20A located at both ends in the circumferential direction C of the coil group Q are electrically connected to the busbar 30.

[0061] As a result, in the coil group Q, adjacent coils 20 in the circumferential direction C are not connected to the busbar 30, but rather the adjacent lead portions 22 of the coils 20 in the circumferential direction C are connected to each other, thereby reducing the number of connection points between the multiple coils 20 and the busbar 30.

[0062] Furthermore, by connecting adjacent lead portions 22 in the circumferential direction C of adjacent coils 20, a coil group Q can be formed, and then the coil group Q can be inserted into the slot SL of the stator core 10. Thus, multiple coils 20 constituting the coil group Q can be inserted together into the slot SL of the stator core 10. As a result, the ease of assembling the coils 20 to the stator core 10 can be improved compared to inserting each coil 20 individually into each slot SL of the stator core 10.

[0063] Furthermore, before inserting the coil group Q into the slot SL of the stator core 10, the lead portions 22 of adjacent coils 20 in the circumferential direction C within the coil group Q are connected. This improves the ease of connection compared to inserting and connecting each coil 20 individually into each slot SL of the stator core 10.

[0064] Therefore, the stator 1 having the above configuration can improve production efficiency.

[0065] Furthermore, in this embodiment, in the coil formation step S1, a first coil 20A is formed by winding a conductor so that the first lead portion 22A is positioned so as to overlap with the first annular portion 21A when viewed in the direction in which the first lead portion 22A extends. In the coil group formation step S2, the first coils 20A are arranged at both ends in the circumferential direction to form a coil group Q.

[0066] This prevents interference between adjacent coil groups Q in the circumferential direction C, specifically between the first lead portions 22A connected to the busbar 30 at both ends of the first coil 20A. Thus, the busbar 30 can be arranged compactly while multiple coil groups Q can be connected to the busbar 30 without interfering with each other.

[0067] Furthermore, in this embodiment, in the coil formation step S1, a second coil 20B is formed by winding a conductor so that the tip of the second lead portion 22B is located outside the first annular portion 20B when viewed in the direction in which the second lead portion 22B extends. In the coil group formation step S2, the second coil 20B is positioned adjacent to the first coil 20A in the circumferential direction C to form a coil group Q.

[0068] By arranging a first coil 20A, where the first lead portion 22A overlaps with the first annular portion 21A when viewed in the direction in which the first lead portion 22A extends, and a second coil 20B, where the tip of the second lead portion 22B is located outside the second annular portion 21B when viewed in the direction in which the second lead portion 22B extends, the first lead portion 22A of the first coil 20A and the second lead portion 22B of the second coil 20B can be positioned close to the circumferential direction C, and the first lead portion 22A and the second lead portion 22B can be easily connected. Therefore, when forming the coil group Q, the first lead portion 22A and the second lead portion 22B can be easily connected, thereby improving the production efficiency of the stator 1.

[0069] Furthermore, in this embodiment, in the coil group formation step S2, if the coil group Q is composed of an odd number of coils 20, the first coil 20A having the same configuration is used as the coils 20 located at both ends in the circumferential direction C in the coil group Q. This reduces the number of types of coils 20 that make up the coil group Q. Therefore, the coils 20 can be produced efficiently. Consequently, the production efficiency of the stator 1 can be improved.

[0070] (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.

[0071] In the above embodiment, the motor 100 has stators 1 located on both sides A1 and A2 of the axial direction A of the rotor 50. However, the motor may have one stator located on either side of the axial direction of the rotor.

[0072] In the above embodiment, the stators 1 located on both sides A1 and A2 of the axial direction A of the rotor 50 are the same shape except that their orientation in the axial direction A is opposite. However, the stator located on one side of the rotor's axial direction and the stator located on the other side may have different shapes.

[0073] In the above embodiment, the motor 100 is an axial gap type motor having an axial gap between the rotor 50 and the stator 1. However, the motor may also be a radial gap type motor having a radial gap between the rotor and the stator. In this case, the teeth of the stator core protrude radially from the core back portion.

[0074] In the above embodiment, the stator core 10 has grooves 111. However, the stator core does not have to have grooves.

[0075] In the above embodiment, the stator core 10 is formed by stacking a single strip of steel sheet, which constitutes the electromagnetic steel sheet, in the radial direction B by winding it around an axis P. However, the stator core may be formed by stacking multiple electromagnetic steel sheets in the axial direction or in the radial direction.

[0076] In the above embodiment, the coil group Q is molded with resin. However, the coil group does not necessarily have to be molded with resin.

[0077] In the above embodiment, the axial length A of the annular portion 21 of the coil 20 is the same as the axial length A of the teeth portion 12 of the stator core 10. However, the axial length of the annular portion of the coil may be longer or shorter than the axial length of the teeth portion of the stator core.

[0078] In the above embodiment, coil group Q has three coils 20. However, a coil group may have two or four or more coils. Also, a coil group may have three or more types of coils. When a coil group has an odd number of coils, the coils located at both ends in the circumferential direction have the same configuration. Therefore, in this case, in the coil group formation process, coils with the same configuration are used as the coils located at both ends in the circumferential direction of the coil group. On the other hand, when a coil group has an even number of coils, the coils located at both ends in the circumferential direction of the coil group have a mirror-image symmetrical configuration when viewed in the radial and axial directions, respectively. Therefore, in this case, in the coil group formation process, coils with a mirror-image symmetrical configuration when viewed in the radial and axial directions are used as the coils located at both ends in the circumferential direction of the coil group. This reduces the number of types of coils that make up the coil group. Therefore, coils can be produced efficiently. Therefore, the production efficiency of the stator can be improved.

[0079] Figure 11 shows an example of the configuration of a coil group Q2 having two coils 2020A and 2020B. The coil group Q2 shown in Figure 11 has a first coil 2020A and a second coil 2020B. The first coil 2020A and the second coil 2020B have a mirror-image configuration. Specifically, the lead portion of the pair of lead portions 2022A of the first coil 2020A that is located on the side of the second coil 2020B, and the lead portion of the pair of lead portions 2022B of the second coil 2020B that is located on the side of the first coil 2020A, extend straight radially from the first annular portion 2021A and the second annular portion 2021B, respectively, and are connected to each other. The lead portion of the pair of lead portions 2022A of the first coil 2020A that is located on the circumferential outer side of the coil group Q2, and the lead portion of the pair of lead portions 2022B of the second coil 2020B that is located on the circumferential outer side of the coil group Q2, are each bent in the circumferential direction C and are positioned to overlap with the first annular portion 2021A and the second annular portion 2021B when viewed radially, and are connected to a busbar (not shown). Note that if the coil group has multiple coils, the configuration is not limited to the above, as long as the coils have a mirror-image symmetrical configuration.

[0080] In the above embodiment, the pair of lead portions 22 in the coil 20 are of the same length. However, as shown in Figure 9, in the coil group Q1, the first coil 120A located at both ends in the circumferential direction C may have a protruding length of the lead portion 122a located at the circumferential end of the pair of lead portions 122a and 122b that is greater than the protruding length of the other lead portion 122b. This allows the lead portion 122a located at the circumferential end of the first coil 120A located at both ends in the circumferential direction C in the coil group Q1 to be easily connected to the busbar. Therefore, the workability when connecting the lead portion 122a to the busbar can be improved. Consequently, the production efficiency of the stator can be improved.

[0081] In the above embodiment, the pair of first lead portions 22A in the first coil 20A are located in a position that overlaps with the first annular portion 21A when viewed in the direction in which the first lead portions 22A extend. However, the tip portions of the pair of first lead portions in the first coil may be located circumferentially outward from the first annular portion when viewed in the direction in which the first lead portions extend.

[0082] In the above embodiment, the tip portions of the pair of second lead portions 22B in the second coil 20B are located circumferentially outward from the first annular portion 21A when viewed in the direction in which the lead portions 22A extend. However, the tip portions of the pair of second lead portions in the second coil may be located in a position that overlaps with the second annular portion when viewed in the direction in which the second lead portions extend.

[0083] In the above embodiment, the pair of first lead portions 22A in the first coil 20A are located on one side A1 of the axial direction A of the first annular portion 21A of the first coil 20A. The pair of second lead portions 22B in the second coil 20B are located on one side A1 of the axial direction A of the second annular portion 21B of the second coil 20B. However, at least one of the pair of first lead portions in the first coil may be located at the axial center or the other of the first annular portion. At least one of the pair of second lead portions in the second coil may be located at the axial center or the other of the second annular portion.

[0084] In the above embodiment, the coil 20 of the stator 1 located at one A1 in the axial direction A relative to the rotor 50 and the coil 1020 of the stator 1 located at the other A2 in the axial direction A have different lead portions 22 and 1022. However, the coil of the stator located at one axial direction relative to the rotor and the coil of the stator located at the other axial direction may have the same lead portion shape. That is, the coil of the stator located at one axial direction relative to the rotor and the coil of the stator located at the other axial direction may be the same coil.

[0085] (Example Configuration) This technology can also be configured as follows:

[0086] (1) A stator having an annular core back portion centered on an axis, and a plurality of teeth portions that protrude axially or radially from the core back portion and are arranged in the circumferential direction, wherein a plurality of slots are formed between adjacent teeth portions in the circumferential direction, a plurality of coils located in the plurality of slots, and a busbar that electrically connects coils of the same phase, wherein each of the plurality of coils has an annular portion around which a conductor is wound, and a pair of lead portions located on the outermost periphery of the annular portion, the circumferential position of adjacent coils relative to the annular portion differs, and the lead portions extend outward toward the busbar into the slot, and the plurality of adjacent coils in the circumferential direction are electrically connected to each other to form a coil group, the coil group is such that adjacent coils in the circumferential direction are joined to each other by their lead portions, and the lead portions located at the circumferential ends of the coils at both ends in the circumferential direction are electrically connected to the busbar.

[0087] (2) In the stator described in (1), the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which the lead portion extends, at least the lead portion located at the circumferential end overlaps with the annular portion of the coil.

[0088] (3) In the stator described in (2), the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which their lead portions extend, a pair of lead portions overlap with the annular portion of the coil, and the coils adjacent to the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which their lead portions extend, the tips of a pair of lead portions are located circumferentially outward from the annular portion of the coil.

[0089] (4) In the stator described in any one of (1) to (3), if the coil group is composed of an odd number of coils, the coils located at both ends in the circumferential direction in the coil group have the same configuration.

[0090] (5) In the stator described in any one of (1) to (3), if the coil group is composed of an even number of coils, the coils located at both ends in the circumferential direction in the coil group have a mirror-image symmetrical configuration when viewed in the radial and axial directions, respectively.

[0091] (6) In the stator described in any one of (1) to (5), the busbar has a busbar body portion extending in the circumferential direction and a lead connection portion extending from the busbar body portion in the direction of the protrusion of the teeth portion, to which the lead portions of the coils located at both ends in the circumferential direction in the coil group are connected, and the pair of lead portions are located in the coil on the side away from the busbar body portion in the direction of the protrusion.

[0092] (7) In the stator described in any one of (1) to (6), the plurality of teeth protrude axially from the core back portion and are arranged circumferentially, the pair of lead portions extend radially inward from the outermost circumference of the coil, and the busbar is located radially inward with respect to the plurality of coils.

[0093] (8) In the stator described in any one of (1) to (7), the coils located at both ends in the circumferential direction in the coil group have a protruding length of the lead portion located at the circumferential end of the pair of lead portions greater than the protruding length of the other lead portion.

[0094] (9) A motor having a stator as described in any one of (1) to (8), and a rotor that rotates with respect to the stator about the axis of the stator.

[0095] (10) A method for manufacturing a stator, comprising: a stator core having an annular core back portion centered on an axis, a plurality of teeth portions protruding axially or 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; a plurality of coils located within the plurality of slots; and busbars that electrically connect coils of the same phase among the plurality of coils, comprising: a coil forming step of winding a conductor to form a plurality of types of coils having an annular portion and a pair of lead portions extending outward from the outermost periphery of the annular portion to the slots, and having different circumferential positions of the pair of lead portions relative to the annular portion; a coil group forming step of electrically connecting the lead portions of adjacent coils in the circumferential direction with respect to the annular portion, with the coils formed in the coil forming step having different circumferential positions of the pair of lead portions arranged circumferentially; a coil group insertion step of inserting the coil group into the slots of the stator core; and a busbar connection step of electrically connecting the lead portions located at the circumferential ends of the coils located at both ends in the circumferential direction to the busbar.

[0096] (11) In the method for manufacturing a stator as described in (10), in the coil forming step, a first coil is formed by winding a conductor so that the first lead portion is positioned to overlap with the first annular portion as an annular portion when viewed in the direction in which the first lead portion as a lead portion extends, and in the coil group forming step, the first coils are arranged at both ends in the circumferential direction to form the coil group.

[0097] (12) In the method for manufacturing a stator as described in (11), the coil forming step is to form a second coil by winding a conductor so that the tip portion of the second lead portion is located outside the second annular portion when viewed in the direction in which the second lead portion extends as a lead portion, and the coil group forming step is to form the coil group by arranging the second coil at a position adjacent to the first coil in the circumferential direction.

[0098] (13) In the method for manufacturing a stator described in any one of (10) to (12), in the coil group formation step, if the coil group is composed of an odd number of coils, coils having the same configuration are used as the coils located at both ends in the circumferential direction in the coil group.

[0099] (14) In the method for manufacturing a stator described in any one of (10) to (12), in the coil group formation step, if the coil group is composed of an even number of coils, coils having a mirror-image symmetrical configuration when viewed in the radial and axial directions are used as the coils located at both ends in the circumferential direction of the coil group.

[0100] The configuration of the present invention is applicable to a stator having a stator core and coils.

[0101] 1 Stator 10 Stator core 11 Core back section 12 Teeth section 20, 1020 Coil 20A, 120A, 1020A, 2020A First coil 20B, 1020B, 2020B Second coil 21, 1021, 2021 Annular section 21A, 1021A, 2021A First annular section 21B, 1021B, 2021B Second annular section 22, 122a, 122b, 1022 Lead section 22A, 1022A, 2022A First lead section 22B, 1022B, 2022B Second lead section 30 Busbar 30A First busbar 30B Second busbar 31 Busbar body section 32 Lead connection section 32A First lead connection section 32B Second lead connection section 35 Terminal connection section 50 Rotor 100 Motor SL Slot P Axis Q, Q1, Q2 Coil group

Claims

1. A stator having an annular core back portion centered on an axis, and a plurality of teeth portions that protrude axially or radially from the core back portion and are arranged in the circumferential direction, wherein a plurality of slots are formed between adjacent teeth portions in the circumferential direction, a plurality of coils located within the plurality of slots, and a busbar that electrically connects coils of the same phase, wherein each of the plurality of coils has an annular portion around which a conductor is wound, and a pair of lead portions located on the outermost periphery of the annular portion, the circumferential positions of adjacent coils relative to the annular portion differ, and the lead portions extend outward toward the busbar into the slot, the plurality of adjacent coils in the circumferential direction are electrically connected to each other to form a coil group, the coil group is such that adjacent coils in the circumferential direction are joined to each other by their lead portions, and the lead portions located at the circumferential ends of the coils at both ends in the circumferential direction are electrically connected to the busbar.

2. A stator according to claim 1, wherein the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which the lead portion extends, at least the lead portion located at the circumferential end overlaps with the annular portion of the coil.

3. A stator according to claim 2, wherein the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which their lead portions extend, a pair of lead portions overlap with the annular portion of the coil, and the coils adjacent to the coils located at both ends in the circumferential direction in the coil group are positioned such that, when viewed in the direction in which their lead portions extend, the tips of a pair of lead portions are located circumferentially outward from the annular portion of the coil.

4. In the stator according to claim 1, if the coil group is composed of an odd number of coils, the coils located at both ends in the circumferential direction in the coil group have the same configuration.

5. A stator according to claim 1, wherein, if the coil group is composed of an even number of coils, the coils located at both ends in the circumferential direction in the coil group have a configuration that is mirror-image symmetrical when viewed in the radial and axial directions, respectively.

6. A stator according to claim 1, wherein the busbar has a busbar body portion extending in the circumferential direction, and a lead connection portion extending from the busbar body portion in the direction of the protrusion of the teeth portion, to which the lead portions of coils located at both ends in the circumferential direction in the coil group are connected, and the pair of lead portions are located on the side of the coil that is away from the busbar body portion in the direction of the protrusion.

7. A stator according to claim 1, wherein the plurality of teeth protrude axially from the core back portion and are arranged circumferentially, the pair of lead portions extend radially inward from the outermost circumference of the coil, and the busbar is located radially inward with respect to the plurality of coils.

8. A stator according to claim 1, wherein, in the coil group, the coils located at both ends in the circumferential direction have a protruding length of the lead portion located at the circumferential end of the pair of lead portions greater than the protruding length of the other lead portion.

9. A motor comprising a stator according to any one of claims 1 to 8, and a rotor that rotates relative to the stator about the axis of the stator.

10. A method for manufacturing a stator having an annular core back portion centered on an axis, a plurality of teeth portions that protrude axially or radially from the core back portion and are arranged in the circumferential direction, and a plurality of slots arranged in the circumferential direction between adjacent teeth portions in the circumferential direction, a plurality of coils located in the plurality of slots, and busbars that electrically connect coils of the same phase among the plurality of coils, comprising: a coil forming step of winding a wire to form a plurality of types of coils having an annular portion and a pair of lead portions extending outward from the outermost circumference of the annular portion to the slots, and having different circumferential positions of the pair of lead portions relative to the annular portion; a coil group forming step of electrically connecting the lead portions of adjacent coils in the circumferential direction with respect to the annular portion, while the coils formed in the coil forming step, with different circumferential positions of the pair of lead portions, are arranged in the circumferential direction; and a coil group insertion step of inserting the coil group into the slots of the stator core. A method for manufacturing a stator, comprising: a busbar connection step of electrically connecting lead portions located at the circumferential ends of coils located at both circumferential ends of the coil group to the busbar.

11. A method for manufacturing a stator according to claim 10, wherein in the coil forming step, a first coil is formed by winding a conductor so that the first lead portion is positioned to overlap with the first annular portion when viewed in the direction in which the first lead portion extends, and in the coil group forming step, the first coils are arranged at both ends in the circumferential direction to form the coil group.

12. A method for manufacturing a stator according to claim 11, wherein in the coil forming step, a second coil is formed by winding a conductor so that the tip portion of the second lead portion is located outside the second annular portion when viewed in the direction in which the second lead portion extends, and in the coil group forming step, the second coil is arranged at a position adjacent to the first coil in the circumferential direction to form the coil group.

13. A method for manufacturing a stator according to claim 10, wherein in the coil group formation step, if the coil group is composed of an odd number of coils, coils having the same configuration are used as coils located at both ends in the circumferential direction in the coil group.

14. A method for manufacturing a stator according to claim 10, wherein in the coil group formation step, if the coil group is composed of an even number of coils, coils having a mirror-image symmetrical configuration in the radial and axial directions are used as coils located at both ends in the circumferential direction of the coil group.

Images