stator

Abstract

The objective of this invention is to provide a technique that simplifies the structure of a stator coil. The stator includes a stator core extending in a cylindrical shape along an axial direction, a plurality of slots arranged circumferentially along the stator core, and a stator coil composed of a plurality of coil segments disposed in the slots and a plurality of buses. The stator coil has a first coil end portion protruding from a first end face of the stator core. Each of the plurality of buses connects the ends of two coil segments protruding from different slots to each other in the first coil end portion. The plurality of buses includes a plurality of first buses arranged in a first plane perpendicular to the axial direction and a plurality of second buses arranged in a second plane axially separated from the first plane. Furthermore, each of the plurality of first buses intersects with a corresponding one of the plurality of second buses when viewed axially.

Description

Technical Field

[0001] The technology disclosed in this specification relates to the stator of an electric motor. Background Technology

[0002] The stator disclosed in Patent Document 1 includes a cylindrical stator core, stator coils disposed on the stator core, and multiple busbars. The multiple busbars electrically connect multiple ends of the stator coils to terminal blocks. The terminal blocks are electrically connected to an inverter driving a motor.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-101381 Summary of the Invention

[0004] Stator coils sometimes consist of multiple coil segments. In this case, multiple slots are arranged circumferentially on the stator core, and U-shaped coil segments are inserted from one end face of the stator core into two separate slots. As a result, multiple U-shaped coil segments are arranged regularly adjacent to each other on one end face of the stator core. However, depending on the wiring structure of the stator coil, it is necessary for some coil segments to intersect with other coil segments three-dimensionally. In this case, the coil segments that intersect three-dimensionally are required to have different shapes or sizes than the other coil segments. Therefore, the required types of wires for the coil segments increase, leading to a more complex stator coil structure and thus increasing the manufacturing cost of the stator. This specification provides a technique that simplifies the structure of stator coils.

[0005] The technology disclosed in this specification is implemented using a stator of an electric motor. The stator comprises: a stator core extending axially in a cylindrical shape between a first end face and a second end face; a plurality of slots disposed on the inner circumferential surface of the stator core, each extending axially and arranged circumferentially along the stator core; and a stator coil comprising a plurality of coil segments disposed in the plurality of slots and a plurality of buses. The stator coil has a first coil end portion protruding from the first end face of the stator core. Each of the plurality of buses connects the ends of two coil segments protruding from different slots to each other in the first coil end portion. The plurality of buses includes a plurality of first buses arranged in a first plane perpendicular to the axial direction and a plurality of second buses arranged in a second plane separated axially from the first plane. Furthermore, each of the plurality of first buses intersects a corresponding one of the plurality of second buses when viewed along the axial direction.

[0006] In the above structure, the ends of two coil segments protruding from different slots are connected to each other via multiple first buses and multiple second buses. The multiple first buses are axially separated relative to the multiple second buses. Therefore, even if a first bus intersects with a corresponding second bus when viewed axially, the first and second buses will not interfere with each other. According to this structure, the path of three-dimensional intersection of the two coil segments with U-shaped bends can be reduced in the end portion of the first coil, thus reducing the number of special coil segments required for this purpose. Therefore, the structure of the stator coil can be simplified. Attached Figure Description

[0007] Figure 1 This is a perspective view of the stator 10 involved in the embodiment.

[0008] Figure 2 This is a perspective view showing the exploded state of the stator 10 involved in the embodiment.

[0009] Figure 3 This is a top view of a portion of the stator 10 when viewed along axis D1.

[0010] Figure 4 It is along Figure 3 A sectional view cut along line IV-IV. Detailed Implementation

[0011] In one embodiment of this technology, the plurality of first buses may have the same shape and be arranged at equal intervals along the circumference. In this case, the plurality of second buses may have the same shape and be arranged at equal intervals along the circumference.

[0012] This structure enables the generalization of multiple first buses and multiple second buses. Therefore, it further simplifies the structure of the stator coil.

[0013] In one embodiment of this technology, the plurality of coil segments may have a plurality of U-shaped coil segments and a plurality of I-shaped coil segments. In this case, each of the plurality of I-shaped coil segments may be connected to another of the plurality of I-shaped coil segments via the first bus or the second bus in the end portion of the first coil.

[0014] This structure allows multiple I-shaped coil segments to be connected to each other via a first or second bus. The relatively easy-to-form I-shaped coil segments can help suppress structural complexity in the stator coils.

[0015] In one embodiment of this technology, each of the plurality of U-shaped coil segments may extend between two different slots in the end portion of the first coil.

[0016] Based on this structure, the structure of the stator coil can be further simplified by using U-shaped coil segments for the parts that do not require three-dimensional intersection.

[0017] In one embodiment of this technology, the first plane may be closer to the first end face of the stator core than the second plane. In this case, each of the plurality of U-shaped coil segments may extend between two different slots between the first plane and the first end face of the stator core.

[0018] According to this structure, interference between the U-shaped coil segment and the multiple first buses arranged on the first plane can be easily avoided.

[0019] (Example)

[0020] like Figure 1 As shown, the stator 10 in this embodiment includes a stator core 20, a stator coil 40, and a bus unit 50. The stator 10, for example, constitutes a three-phase AC motor for an electric vehicle.

[0021] The stator core 20 is configured, for example, by stacking multiple silicon steel plates. The stator core 20 extends in a cylindrical shape along the central axis A1. Hereinafter, the direction parallel to the central axis A1 will be referred to as axial direction D1, the direction orthogonal to axial direction D1 will be referred to as radial direction D2, and the direction along the outer periphery of the stator core 20 and orthogonal to axial direction D1 and radial direction D2 will be referred to as circumferential direction D3.

[0022] The stator core 20 includes: a first end face 21 located at one end along the axial direction D1; a second end face 22 located at the other end along the axial direction D1; and an inner circumferential surface 23 defining a space extending through the center of the stator core 20 along the axial direction D1. That is, the stator core 20 extends along the axial direction D1 between the first end face 21 and the second end face 22. A slot group 30 is formed on the inner circumferential surface 23 of the stator core 20. The slot group 30 has multiple slots extending radially D2 from the inner circumferential surface 23. The multiple slots of the slot group 30 are slots extending axially D1 from the first end face 21 to the second end face 22. The multiple slots are arranged circumferentially D3.

[0023] The stator coil 40 includes a U-phase coil, a V-phase coil, and a W-phase coil. The positions of each phase coil on the circumferential direction D3 within the stator core 20 are different, but they are generally interchangeable in other structural aspects. The stator coil 40 is wound with respect to each slot of the slot group 30 in a manner known as distributed winding. The stator coil 40 has a first coil end portion 41 protruding from the first end face 21 of the stator core 20 and a second coil end portion 42 protruding from the second end face 22.

[0024] In the first coil end portion 41, multiple coil segments protrude from the first end face 21 through the slots of the slot group 30. Although not shown in the figure, the first coil end portion 41 includes, for example, multiple terminals for connecting the power line or the neutral line.

[0025] In the second coil end portion 42, multiple coil segments protrude from the second end face 22 through the slots of the slot group 30. In the second coil end portion 42, corresponding two front ends of the multiple coil segments engage with each other while being twisted.

[0026] Bus unit 50 is opposite to the first end face 21 of stator core 20 and has a cylindrical shape. Bus unit 50 includes a first bus housing 52, a second bus housing 54, a cover 56, and a first bus assembly 61 and a second bus assembly 62 (see reference). Figure 2 The first busbar housing 52, the second busbar housing 54, and the cover 56 are fitted together to form a housing that accommodates the first busbar assembly 61 and the second busbar assembly 62. The first busbar housing 52, the second busbar housing 54, and the cover 56 are made of resin, for example.

[0027] like Figure 2 As shown, the end portion 41 of the first coil has multiple I-shaped coil segments 44 and 46 and multiple U-shaped coil segments 48. Figure 2 Below, enlarged views of the I-shaped coil segments 44 and 46 and the U-shaped coil segment 48 are shown. As shown in the enlarged views, the U-shaped coil segment 48 has two straight portions 48S and a connecting portion 48C connecting the straight portions 48S. That is, the U-shaped coil segment 48 has a shape that reverses the letter "U" in the axial direction D1. The U-shaped coil segment 48 is inserted from the first end face 21 side into two different slots included in the slot group 30. As a result, the front ends of each straight portion 48S protrude from the second end face 22, forming a second coil end portion 42. The U-shaped coil segment 48 extends in the first coil end portion 41 between the two different slots. Therefore, the U-shaped coil segment 48 allows the coil segment to be easily arranged between the two slots. In addition, the shape of the U-shaped coil segment 48 is not strictly limited to "U", as long as it has two straight portions 48S inserted into two different slots and a connecting portion 48C connecting them.

[0028] Unlike the U-shaped coil segment 48, the I-shaped coil segments 44 and 46 do not have a connecting portion. The I-shaped coil segment 44 is simply inserted into a slot. As shown in the enlarged view, for example, the I-shaped coil segment 44 has a first straight portion 44F extending linearly within the slot, a curved portion 44C extending radially outward from the first end face 21 after the front end of the first straight portion 44F protrudes from the front end of the first end face 21, and a second straight portion 44S extending further along the axial direction D1 from the front end of the curved portion 44C. In contrast, the I-shaped coil segment 46 does not have a curved portion and extends linearly along the axial direction D1. Thus, the term "I-shaped" in this specification is not limited to a shape that extends linearly like the letter "I", but refers to a shape in which the end of the coil segment protrudes from both the first end face 21 and the second end face 22 through a slot.

[0029] The first bus group 61 is disposed between the cover 56 and the second bus housing 54. The first bus group 61 consists of nine first buses 61A. Although details will be described later, each first bus 61A is a flat conductive component connected to I-shaped coil segments 44, 46. Each first bus 61A has two through holes H2 that engage with the I-shaped coil segments 44, 46. The I-shaped coil segments 44, 46 engage with the through holes H2 of each first bus 61A through the through holes H1 of the cover 56. Each first bus 61A has the same shape and is evenly arranged along the circumferential direction D3 at intervals R1.

[0030] The second bus group 62 is disposed between the second bus housing 54 and the first bus housing 52. Similar to the first bus group 61, the second bus group 62 also consists of nine second bus groups 62A. In this embodiment, each second bus group 62A has the same shape as the first bus group 61A and is evenly arranged along the circumferential direction D3 at intervals R1. Therefore, each second bus group 62A has two through holes H2 that engage with the I-shaped coil segments 44 and 46. The I-shaped coil segments 44 and 46 engage with the through holes H2 of each second bus group 62A through the through holes H1 of the cover 56 and the through holes H3 of the second bus housing 54. Furthermore, in a modified example, the second bus group 62A may have a different shape than the first bus group 61A.

[0031] refer to Figure 3 and Figure 4 The detailed structure of the end portion 41 of the first coil of the stator 10 will be described. Figure 3 This is a top view showing a portion of the stator 10 as viewed along the axial direction D1 from the first end face 21 side. Additionally, for ease of understanding, in... Figure 3 The description of the housings 52, 54 and cover 56 of the bus unit 50 is omitted.

[0032] exist Figure 3The diagram shows slots 31 to 38 in the slot group 30 of the stator core 20. For example, 48 slots are arranged along the circumferential direction D3 on the inner circumferential surface 23 of the stator core 20.

[0033] In each slot, the coil segments constituting each layer of the stator coil 40 are stacked in six layers along the radial direction D2. In this specification, the innermost layer along the radial direction D2 (i.e., Figure 3 The layer on the paper side is designated as layer 1 (L1), and the outermost radially outermost layer is designated as layer 6 (L6). Furthermore, as described above, the coils of each phase have the same structure. Therefore, in Figure 3 The document describes the coil segments 44A, 44B, 46A, 46B, 48A, 48B, and the first bus 61A and the second bus 62A that constitute the U-phase coil in the stator coil 40, omitting other coil segments and buses. However, the U-phase coil segments are similarly arranged in other slots along the circumferential direction D3. Moreover, similar to the U-phase, the coil segments and buses of the V-phase and W-phase are also regularly arranged along the circumferential direction D3.

[0034] The coil segment of the U-phase coil, for example, starts from the sixth layer L6 of slot 1 (not shown) in slot group 30 and extends from the first end face 21 of the stator core 20 toward the second end face 22 within slot 1. Then, the coil segment is displaced on the second end face 22 of the stator core 20 toward the sixth layer L6 of slot 8, extending from the second end face 22 toward the first end face 21 within slot 8. In this way, the coil segments of the U-phase coil are arranged in each layer L1 to L6 of the plurality of slots.

[0035] like Figure 3 As shown, for example, in slots 31 to 38, the coil segment of the U-phase coil extends from the second end face 22 toward the first end face 21 within the first layer L1 of slot 31 and protrudes from the first end face 21, displacing circumferentially D3 toward the second layer L2 of slot 37, and extending from the first end face 21 toward the second end face 22 within the second layer L2 of slot 37. In the stator 10 of this embodiment, this path between slots 31 and 37 of the U-phase coil is formed by a U-shaped coil segment 48B.

[0036] Furthermore, after passing through other slots, the coil segment of the U-phase coil extends from the second end face 22 toward the first end face 21 within the third layer L3 of slot 31, protruding from the first end face 21, and shifts circumferentially D3 toward the fourth layer L4 of slot 37, extending from the first end face 21 toward the second end face 22 within the fourth layer L4 of slot 37. This path between slots 31 and 37 of the U-phase coil is formed by a U-shaped coil segment 48A.

[0037] Furthermore, after passing through other slots, the coil segment of the U-phase coil extends from the second end face 22 toward the first end face 21 within the fifth layer L5 of slot 31, protruding from the first end face 21, and shifts circumferentially D3 toward the sixth layer L6 of slot 37, extending from the first end face 21 toward the second end face 22 within the sixth layer L6 of slot 37. This path between slots 31 and 37 of the U-phase coil is formed by two I-shaped coil segments 46A and 44B and the second busbar 62A.

[0038] Furthermore, after passing through other slots, the coil segment of the U-phase coil extends from the second end face 22 toward the first end face 21 within the sixth layer L6 of slot 32, protruding from the first end face 21, and displaces along the circumferential direction D3 toward the fifth layer L5 of slot 38, extending from the first end face 21 toward the second end face 22 within the fifth layer L5 of slot 38. This path between slot 32 and slot 38 is formed by two I-shaped coil segments 44A and 46B and the first busbar 61A. Thus, the U-phase coil has both a path that displaces towards the circumferential direction D3 closer to the outer side of the radial direction D2 (e.g., the second busbar 62A) and a path that displaces towards the circumferential direction D3 closer to the inner side of the radial direction D2 (e.g., the first busbar 61A). Therefore, the U-phase coil of the stator 10 in this embodiment, for example, includes paths that intersect each other when viewed along the axial direction D1, such as the first busbar 61A and the second busbar 62A.

[0039] In the past, to form paths that intersect each other when viewed along the axial direction D1, two U-shaped coil segments were sometimes made to intersect three-dimensionally to avoid interference. In this case, the shapes of the two U-shaped coil segments become more complex, requiring the preparation of special U-shaped coil segments for three-dimensional intersection. Therefore, for example, the types of wires used in the U-shaped coil segments increase, and sometimes the manufacturing cost of the stator 10 increases.

[0040] In the stator 10, the first busbar 61A connects the end of the I-shaped coil segment 44A protruding from the sixth layer L6 of slot 32 and the end of the I-shaped coil segment 46B protruding from the fifth layer L5 of slot 38. Furthermore, the second busbar 62A connects the end of the I-shaped coil segment 46A protruding from the fifth layer L5 of slot 31 and the end of the I-shaped coil segment 44B protruding from the sixth layer L6 of slot 37. The I-shaped coil segments 44 and 46 can be formed relatively easily, for example, compared to the U-shaped coil segment 48 formed by bending a single coil segment by 180°. By combining the I-shaped coil segments 44 and 46 with each busbar 61A and 62A to form the coil segments, the structural complexity of the stator coil 40 can be suppressed.

[0041] Moreover, such as Figure 4As shown, the first busbar 61A is positioned on a first plane P1 orthogonal to the axis D1. The second busbar 62A is positioned on a second plane P2 orthogonal to the axis D1. Planes P1 and P2 are parallel to each other and separate from one another. Therefore, as... Figure 3 As shown, the busbars 61A and 62A intersect when viewed along the axial direction D1, but do not interfere with each other. Thus, the busbars 61A and 62A can easily intersect in three dimensions. Furthermore, as... Figure 4 As shown in the cross-sectional view S1, the I-shaped coil segment 44A disposed in the 6th layer L6 extends radially outward from the aforementioned bend 44C towards the outer side of D2 (i.e., Figure 4 (The right side of the cross-sectional view S1) is bent. As a result, the arrangement space for coil segments through other layers L1 to L5 can be expanded inside the radial D2 of the I-shaped coil segment 44A.

[0042] (Effect of this embodiment)

[0043] Thus, according to the stator 10 of this embodiment, interference between the first bus 61A connecting the I-shaped coil segments 44A and 46B and the second bus 62A connecting the I-shaped coil segments 46A and 44B can be avoided in the first coil end portion 41 via a relatively easy path. For example, by changing the axial length D1 of the I-shaped coil segments 44A, 44B, 46A, and 46B, the position of the axial D1 of each bus 61A and 62A can be adjusted, thus making it easy to connect the ends of the I-shaped coil segments 44A, 44B, 46A, and 46B to the circumferential D3. The number of paths where the U-shaped coil segments 48 intersect can be reduced, and the variety of U-shaped coil segments 48 can be reduced. Therefore, the structure of the stator coil 40 can be simplified.

[0044] And, as Figure 3 As shown, the first busbar 61A connecting the I-shaped coil segments 44A and 46B extends across five slots circumferentially D3, displaced only one layer radially D2. In other slots (not shown), the U-phase coil also has a portion extending across five slots circumferentially D3, displaced only one layer radially D2. Therefore, by using multiple first busbars 61A with the same shape, the I-shaped coil segments of the U-phase coil can be easily connected. Furthermore, as described above, the V-phase and W-phase coils have the same structure as the U-phase coil. Therefore, using the first busbar 61A, the I-shaped coil segments of the V-phase and W-phase coils can be connected in the same way as the U-phase coil. Since the shape of the first busbar 61A can be generalized, the structure of the stator 10 can be further simplified.

[0045] Furthermore, similar to the first busbar 61A, the second busbar 62A, connecting the I-shaped coil segments 44B and 46A, extends across five slots along the circumferential direction D3, and is displaced only one layer in the radial direction D2. Therefore, the second busbar 62A has a shape that reverses the shape of the first busbar 61A in the axial direction D1. That is, the second busbar 62A and the first busbar 61A have the same shape. Besides the first busbar 61A, the shape of the second busbar 62A can also be generalized, thus further simplifying the structure of the stator 10.

[0046] Furthermore, the first plane P1 is positioned between the second plane P2 and the first end face 21. That is, the first plane P1 is closer to the first end face 21 than the second plane P2. Also, the U-shaped coil segments 48A and 48B extend circumferentially D3 between the first plane P1 and the first end face 21, extending between different slots 31 and 37. In the axial direction D1, the U-shaped coil segments 48A and 48B are separated from the first plane P1. Therefore, interference between the first busbar 61A positioned on the first plane P1 and the U-shaped coil segments 48A and 48B can be easily avoided. Moreover, regarding the portion that does not require three-dimensional intersection, by employing the U-shaped coil segment 48A, the structure of the stator coil 40 can be simplified more easily compared to a structure where all coil segments are formed from I-shaped coil segments and busbars.

[0047] The following describes some considerations for this embodiment. The first bus group 61 may include first buses 61A having different shapes. Furthermore, multiple first buses 61A may be arranged at different intervals along the circumferential direction D3.

[0048] The stator 10 may not have a second bus group 62. Furthermore, in a further variation, the stator 10 may also have a third bus group that is further away from the first end face 21 than the second bus group 62.

[0049] The above provides a detailed description of specific examples of the technology disclosed in this specification. However, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples illustrated above. Furthermore, the technical elements described in this specification or drawings exert their technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of application. Moreover, the technology illustrated in this specification or drawings simultaneously achieves multiple objectives, wherein achieving one of these objectives is itself technically useful.

[0050] Symbol Explanation

[0051] 10-Stator, 20-Stator core, 21-First end face, 22-Second end face, 23-Inner circumferential surface, 30-Slot group, 31-38-Slots, 40-Stator coil, 41-End portion of the first coil, 42-End portion of the second coil, 44, 44A, 44B, 46, 46A, 46B-I-shaped coil segments, 44C-Bent section, 44F-First straight section, 44S-Second straight section, 48, 48A, 48B-U Character-shaped coil segment, 48C-connector, 48S-straight section, 50-bus unit, 52-first bus housing, 54-second bus housing, 56-cover, 61-first bus group, 61A-first bus, 62-second bus group, 62A-second bus, A1-central shaft, D1-axial direction, D2-radial direction, D3-circumferential direction, H1, H2, H3-through holes, P1-first plane, P2-second plane.

Claims

1. A stator that is a stator of an electric motor, the stator characterized by comprising: a stator core that extends in a cylindrical shape in an axial direction between a first end surface and a second end surface; a plurality of slots that are provided to an inner peripheral surface of the stator core, each extending in the axial direction and arranged in a circumferential direction of the stator core; and a stator coil that is constituted by a plurality of coil segments arranged in the plurality of slots and a plurality of bus bars, the stator coil having a first coil end portion that protrudes from the first end surface of the stator core, the plurality of bus bars each connecting end portions of two coil segments that protrude from different slots to each other in the first coil end portion, the plurality of bus bars including a plurality of first bus bars arranged on a first plane perpendicular to the axial direction and a plurality of second bus bars arranged on a second plane separated from the first plane in the axial direction, the plurality of first bus bars each intersecting a corresponding one of the plurality of second bus bars when viewed in the axial direction.

2. The stator according to claim 1, wherein the plurality of first bus bars have the same shape as each other and are arranged at equal intervals in the circumferential direction, and the plurality of second bus bars have the same shape as each other and are arranged at equal intervals in the circumferential direction.

3. The stator according to claim 1, wherein the plurality of coil segments include a plurality of U-shaped coil segments and a plurality of I-shaped coil segments, and the plurality of I-shaped coil segments each are connected to another one of the plurality of I-shaped coil segments via the first bus bar or the second bus bar in the first coil end portion.

4. The stator according to claim 3, wherein the plurality of U-shaped coil segments each extend between two different slots in the first coil end portion.

5. The stator according to claim 1, wherein the first plane is closer to the first end surface of the stator core than the second plane, and the plurality of U-shaped coil segments each extend between two different slots between the first plane and the first end surface of the stator core. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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