stata

Abstract

This technology provides a way to simplify the configuration of the stator coil. [Solution] The stator comprises a stator coil comprising a stator core extending cylindrically along the axial direction, a plurality of slots arranged along the circumferential direction of the stator core, a plurality of coil segments arranged in the plurality of slots, and a plurality of busbars. The stator coil has a first coil end portion protruding from a first end face of the stator core. Each of the plurality of busbars connects the ends of two coil segments protruding from different slots at the first coil end portion. The plurality of busbars includes a plurality of first busbars arranged on a first plane perpendicular to the axial direction, and a plurality of second busbars arranged on a second plane spaced apart axially from the first plane. Furthermore, each of the plurality of first busbars intersects with a corresponding one of the plurality of second busbars when viewed along the axial direction.

Description

Technical Field

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

Background Art

[0002] The stator disclosed in Patent Document 1 includes a cylindrical stator core, a stator coil disposed on the stator core, and a plurality of busbars. The plurality of busbars electrically connect the plurality of ends of the stator coil to a terminal block. The terminal block is electrically connected to an inverter that drives the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The stator coil may be composed of a plurality of coil segments. In this case, the stator core is provided with a plurality of slots along the circumferential direction, and the U-shaped coil segments are inserted from one end face of the stator core with respect to two slots spaced apart from each other. As a result, on one end face of the stator core, a large number of coil segments curved in a U-shape are regularly arranged while being adjacent to each other. However, depending on the connection structure of the stator coil, it is necessary to make some coil segments intersect three-dimensionally with other coil segments. In this case, the coil segments to be intersected three-dimensionally require different shapes and sizes from other coil segments. For this reason, the configuration of the stator coil becomes complicated, such as an increase in the types of wire required for the coil segments, and the manufacturing cost of the stator increases. In this specification, a technology that can simplify the configuration of the stator coil is provided.

Means for Solving the Problems

[0005] The technology disclosed herein is embodied in a stator for an electric motor. The stator comprises a stator core extending cylindrically in the axial direction between a first end face and a second end face, and a stator coil comprising a plurality of slots provided on the inner circumferential surface of the stator core, each extending in the axial direction and arranged along the circumferential direction of the stator core, a plurality of coil segments arranged in the plurality of slots, and a plurality of busbars. The stator coil has a first coil end portion projecting from the first end face of the stator core. Each of the plurality of busbars connects the ends of two coil segments projecting from different slots in the first coil end portion. The plurality of busbars includes a plurality of first busbars arranged on a first plane perpendicular to the axial direction, and a plurality of second busbars arranged on a second plane spaced apart in the axial direction from the first plane. Furthermore, each of the plurality of first busbars intersects with a corresponding one of the plurality of second busbars when viewed along the axial direction.

[0006] In the above configuration, the ends of two coil segments protruding from different slots are connected to each other by multiple first busbars and multiple second busbars. The multiple first busbars are spaced apart axially from the multiple second busbars. Therefore, even if a first busbar intersects with a corresponding second busbar when viewed along the axial direction, the first and second busbars do not interfere with each other. With this configuration, the paths through which the two U-shaped curved coil segments intersect in the first coil end portion can be reduced, thus reducing the number of special coil segments required. This simplifies the stator coil configuration. [Brief explanation of the drawing]

[0007] [Figure 1] A perspective view of the stator 10 according to the embodiment. [Figure 2] A perspective view showing the disassembled state of the stator 10 according to the embodiment. [Figure 3] A partial plan view of the stator 10 as seen along the axial direction D1. [Figure 4] A cross-sectional view along line IV-IV in Figure 3. [Modes for carrying out the invention]

[0008] In one embodiment of this technology, the plurality of first busbars may have the same shape as each other and be arranged at equal intervals along the circumferential direction. In that case, the plurality of second busbars may have the same shape as each other and be arranged at equal intervals along the circumferential direction.

[0009] This configuration allows for the commonality of multiple first busbars, as well as multiple second busbars. Therefore, the stator coil configuration can be simplified.

[0010] In one embodiment of this technology, the plurality of coil segments may include 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 at the first coil end portion to another of the plurality of I-shaped coil segments via the first busbar or the second busbar.

[0011] With this configuration, multiple I-shaped coil segments can be connected to each other via a first or second busbar. By utilizing relatively easy-to-form I-shaped coil segments, the complexity of the stator coil configuration can be suppressed.

[0012] In one embodiment of this technology, each of the plurality of U-shaped coil segments may extend between two different slots at the first coil end portion.

[0013] With this configuration, the stator coil configuration can be further simplified by using U-shaped coil segments in sections where grade separation is not required.

[0014] 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.

[0015] With this configuration, interference between the U-shaped coil segment and the multiple first busbars arranged in the first plane can be easily avoided.

[0016] (Examples) As shown in Figure 1, the stator 10 of this embodiment comprises a stator core 20, a stator coil 40, and a busbar unit 50. The stator 10 constitutes, for example, a three-phase AC motor for an electric vehicle.

[0017] The stator core 20 is constructed, for example, by laminating multiple silicon steel plates. The stator core 20 extends cylindrically along the central axis A1. Hereinafter, the direction parallel to the central axis A1 will be referred to as the axial direction D1, the direction perpendicular to the axial direction D1 will be referred to as the radial direction D2, and the direction along the outer circumference of the stator core 20 that is perpendicular to the axial direction D1 and the radial direction D2 will be referred to as the circumferential direction D3.

[0018] The stator core 20 includes a first end face 21 located at one end in the axial direction D1, a second end face 22 located at the other end in the axial direction D1, and an inner peripheral surface 23 that defines a space penetrating the central portion 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 peripheral surface 23 of the stator core 20. The slot group 30 includes a plurality of slots extending along the radial direction D2 from the inner peripheral surface 23. Each of the plurality of slots in the slot group 30 is a groove extending in the axial direction D1 from the first end face 21 to the second end face 22. The plurality of slots are arranged along the circumferential direction D3.

[0019] The stator coil 40 includes a U-phase coil, a V-phase coil, and a W-phase coil. The coils of each phase have different positions in the circumferential direction D3 in the stator core 20, but the other configurations are common to each other. The stator coil 40 is wound in a so-called distributed winding manner with respect to each slot in the slot group 30. The stator coil 40 includes 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.

[0020] In the first coil end portion 41, a plurality of coil segments that have passed through each slot in the slot group 30 protrude from the first end face 21. Although not shown, the first coil end portion 41 includes, for example, a plurality of terminals for connecting a power line or a neutral line.

[0021] [[ID=1X]]In the second coil end portion 42, a plurality of coil segments that have passed through each slot in the slot group 30 protrude from the second end face 22. In the second coil end portion 42, the corresponding two tip portions of the plurality of coil segments are joined to each other while being twisted.

[0022] The bus bar unit 50 faces the first end face 21 of the stator core 20 and has a cylindrical shape. The bus bar unit 50 includes a first bus bar case 52, a second bus bar case 54, a cover 56, a first bus bar group 61 and a second bus bar group 62 (see FIG. 2). The first bus bar case 52, the second bus bar case 54, and the cover 56 are fitted to each other to form a case for accommodating the first bus bar group 61 and the second bus bar group 62. The first bus bar case 52, the second bus bar case 54, and the cover 56 are made of, for example, resin.

[0023] As shown in FIG. 2, the first coil end portion 41 includes a plurality of I-shaped coil segments 44, 46 and a plurality of U-shaped coil segments 48. Below FIG. 2, enlarged views of the I-shaped coil segments 44, 46 and an enlarged view of the U-shaped coil segment 48 are shown. As shown in the enlarged view, the U-shaped coil segment 48 includes two straight portions 48S and a connecting portion 48C that connects the straight portions 48S to each other. That is, the U-shaped coil segment 48 has a shape in which the alphabetic "U" is inverted in the axial direction D1. The U-shaped coil segment 48 is inserted into two different slots included in the slot group 30 from the side of the first end face 21. As a result, each tip of the straight portion 48S protrudes from the second end face 22 to form the second coil end portion 42. The U-shaped coil segment 48 extends between the two different slots in the first coil end portion 41. Therefore, the U-shaped coil segment 48 can easily arrange a coil segment between the two slots. Note that the shape of the U-shaped coil segment 48 is not strictly limited to a "U" shape, and it may include two straight portions 48S inserted into two different slots and a connecting portion 48C that connects them.

[0024] 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 inserted into only one slot. As shown in the enlarged view, for example, the I-shaped coil segment 44 comprises a first straight portion 44F that extends linearly within the slot, a bent portion 44C that extends radially D2 outward from the tip of the first straight portion 44F after it protrudes from the first end face 21, and a second straight portion 44S that further extends along the axial direction D1 from the tip of the bent portion 44C. In contrast, the I-shaped coil segment 46 does not have a bent 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 only linearly like the letter "I", but also 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 after passing through a single slot.

[0025] The first busbar group 61 is positioned between the cover 56 and the second busbar case 54. The first busbar group 61 consists of nine first busbars 61A. As will be described in detail later, each first busbar 61A is a flat conductive member connected to I-shaped coil segments 44 and 46. Each first busbar 61A has two through holes H2 that engage with the I-shaped coil segments 44 and 46. The I-shaped coil segments 44 and 46 pass through the through hole H1 of the cover 56 and engage with the through holes H2 of each first busbar 61A. Each first busbar 61A has the same shape as the others and is arranged evenly along the circumferential direction D3 at intervals R1.

[0026] The second busbar group 62 is positioned between the second busbar case 54 and the first busbar case 52. Similar to the first busbar group 61, the second busbar group 62 is also composed of nine second busbars 62A. In this embodiment, each second busbar 62A has the same shape as the first busbar 61A and is evenly arranged along the circumferential direction D3 at intervals R1. Therefore, each second busbar 62A has two through holes H2 that engage with I-shaped coil segments 44 and 46. The I-shaped coil segments 44 and 46 pass through the through hole H1 in the cover 56 and the through hole H3 in the second busbar case 54 to engage with the through holes H2 of each second busbar 62A. In modified examples, the second busbars 62A may have a different shape from the first busbars 61A.

[0027] The detailed structure of the first coil end portion 41 of the stator 10 will be described with reference to Figures 3 and 4. Figure 3 shows a plan view of a part of the stator 10 as seen along the axial direction D1 from the first end face 21 side. For the sake of understanding, the cases 52, 54 and cover 56 of the busbar unit 50 are omitted from Figure 3.

[0028] Figure 3 shows slots 31 to 38 of 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.

[0029] Each slot contains six layers of coil segments that constitute each layer of the stator coil 40, stacked along the radial direction D2. In this specification, the innermost layer in the radial direction D2 (i.e., the upper side of the paper in Figure 3) is referred to as the first layer L1, and the outermost layer in the radial direction is referred to as the sixth layer L6. As mentioned earlier, the coils of each phase have a similar configuration. For this reason, Figure 3 shows only the coil segments 44A, 44B, 46A, 46B, 48A, and 48B that constitute the U-phase coil of the stator coil 40, and the first busbar 61A and the second busbar 62A, while omitting the other coil segments and busbars. However, the U-phase coil segments are similarly arranged in other slots along the circumferential direction D3. Furthermore, the V-phase and W-phase coil segments and busbars are also regularly arranged along the circumferential direction D3, similar to the U-phase.

[0030] The coil segment of the U-phase coil starts, for example, from the sixth layer L6 of slot 1 (not shown) in the slot group 30, and extends within slot 1 from the first end face 21 to the second end face 22 of the stator core 20. Then, at the second end face 22 of the stator core 20, the coil segment is displaced to the sixth layer L6 of slot 8, and extends within slot 8 from the second end face 22 to the first end face 21. In this way, the coil segments of the U-phase coil are arranged in each layer L1 to L6 of multiple slots.

[0031] As shown in Figure 3, 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, protruding from the first end face 21, displaced along the circumferential direction D3 toward the second layer L2 of slot 37, and extends 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, the path between slots 31 and 37 of the U-phase coil is formed by a U-shaped coil segment 48B.

[0032] Furthermore, the coil segment of the U-phase coil, after passing through other slots, extends from the second end face 22 toward the first end face 21 within the first layer L3 of slot 31, protrudes from the first end face 21, is displaced along the circumferential direction D3 toward the fourth layer L4 of slot 37, and extends from the first end face 21 toward the second end face 22 within the fourth layer L4 of slot 37. This path between slot 31 and slot 37 of the U-phase coil is formed by the U-shaped coil segment 48A.

[0033] Furthermore, the coil segments of the U-phase coil, after passing through other slots, extend within the fifth layer L5 of slot 31 from the second end face 22 toward the first end face 21, protrude from the first end face 21, displace along the circumferential direction D3 toward the sixth layer L6 of slot 37, and extend within the sixth layer L6 of slot 37 from the first end face 21 toward the second end face 22. This path of the U-phase coil between slots 31 and 37 is formed by two I-shaped coil segments 46A and 44B and a second busbar 62A.

[0034] Furthermore, the coil segments of the U-phase coil, after passing through other slots, extend from the second end face 22 to the first end face 21 within the sixth layer L6 of slot 32, protrude from the first end face 21, displace along the circumferential direction D3 to the fifth layer L5 of slot 38, and extend from the first end face 21 to 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 a first busbar 61A. Thus, the U-phase coil includes both a path that is displaced more outward in the radial direction D2 on one side of the circumferential direction D3 (e.g., the second busbar 62A) and a path that is displaced more inward in the radial direction D2 on one side of the circumferential direction D3 (e.g., the first busbar 61A). Therefore, the U-phase coils of the stator 10 in this embodiment may include paths that intersect each other when viewed along the axial direction D1, such as the first busbar 61A and the second busbar 62A.

[0035] Conventionally, to form paths that intersect each other when viewed along the axial direction D1, two U-shaped coil segments were sometimes made to intersect in a three-dimensional manner to avoid interference. In this case, the shape of the two U-shaped coil segments becomes complex, and it becomes necessary to prepare a special U-shaped coil segment for the three-dimensional intersection. For example, this could increase the number of wire types for the U-shaped coil segments, thus increasing the manufacturing cost of the stator 10.

[0036] 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 to 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 to 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 compared to, for example, the U-shaped coil segment 48, which is formed by curving a single coil segment by 180°. By forming the coil segments by combining the I-shaped coil segments 44 and 46 with the respective busbars 61A and 62A, the complexity of the stator coil 40 configuration can be suppressed.

[0037] Furthermore, as shown in Figure 4, the first busbar 61A is positioned on a first plane P1 perpendicular to the axial direction D1. The second busbar 62A is positioned on a second plane P2 perpendicular to the axial direction D1. The planes P1 and P2 are parallel to each other and spaced apart. Therefore, as shown in Figure 3, although the busbars 61A and 62A intersect when viewed along the axial direction D1, they do not interfere with each other. In this way, the busbars 61A and 62A can easily intersect in three dimensions. Furthermore, as shown in the cross-sectional view S1 of Figure 4, the I-shaped coil segment 44A positioned in the sixth layer L6 is bent outward in the radial direction D2 (i.e., to the right in the cross-sectional view S1 of Figure 4) by the aforementioned bend 44C. This expands the space inside the radial direction D2 of the I-shaped coil segment 44A for routing coil segments that have passed through the other layers L1 to L5.

[0038] (Effects of this embodiment) Thus, according to the stator 10 of this embodiment, interference between the first busbar 61A connecting the I-shaped coil segments 44A and 46B and the second busbar 62A connecting the I-shaped coil segments 46A and 44B can be avoided in the first coil end portion 41 by a relatively easy path. For example, by changing the length of the axial direction D1 of the I-shaped coil segments 44A, 44B, 46A, and 46B, the position of the axial direction D1 where each busbar 61A and 62A is positioned can be adjusted, so that the ends of the I-shaped coil segments 44A, 44B, 46A, and 46B can be easily connected in the circumferential direction D3. The paths through which the U-shaped coil segments 48 intersect can be reduced, and the number of types of U-shaped coil segments 48 can be reduced. Therefore, the configuration of the stator coil 40 can be simplified.

[0039] Furthermore, as shown in Figure 3, the first busbar 61A connecting the I-shaped coil segments 44A and 46B extends across five slots along the circumferential direction D3 and is displaced by one layer in the radial direction D2. In other slots not shown, the U-phase coil also has a portion that extends across five slots along the circumferential direction D3 and is displaced by one layer in the radial direction D2. Therefore, the I-shaped coil segments of the U-phase coil can be easily connected by using multiple first busbars 61A having the same shape. Moreover, as mentioned earlier, the V-phase coil and the W-phase coil have the same configuration as the U-phase coil. Therefore, the I-shaped coil segments of the V-phase coil and the W-phase coil can be connected using the first busbar 61A, similar to the U-phase coil. Since the shape of the first busbar 61A can be standardized, the configuration of the stator 10 can be further simplified.

[0040] Furthermore, similar to the first busbar 61A, the second busbar 62A, which connects the I-shaped coil segments 44B and 46A, extends across five slots along the circumferential direction D3 and is displaced by one layer in the radial direction D2. Therefore, the second busbar 62A has a shape that is the same as the first busbar 61A but inverted in the axial direction D1. In other words, the second busbar 62A and the first busbar 61A have the same shape. Since the shape of the second busbar 62A can be standardized in addition to the first busbar 61A, the configuration of the stator 10 can be further simplified.

[0041] 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 along the circumferential direction D3 between the first plane P1 and the first end face 21, and extend between different slots 31 and 37. In the axial direction D1, the U-shaped coil segments 48A and 48B are spaced apart 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. Furthermore, by using the U-shaped coil segment 48A in parts where overpassing is not required, the configuration of the stator coil 40 can be simplified compared to a configuration in which all coil segments are formed by I-shaped coil segments and busbars.

[0042] Points to note regarding this embodiment are described below. The first busbar group 61 may include first busbars 61A having different shapes from each other. Furthermore, multiple first busbars 61A may be arranged along the circumferential direction D3 at different intervals.

[0043] The stator 10 does not necessarily have to include the second busbar group 62. In further modifications, the stator 10 may further include a third busbar group that is spaced further apart from the first end face 21 than the second busbar group 62.

[0044] The specific examples of the technologies disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples described above. Furthermore, the technical elements described herein or in the drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated herein or in the drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]

[0045] 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: First coil end portion, 42: Second coil end portion, 44, 44A, 44B, 46, 46A, 46B: I-shaped coil segment, 44C: Bent portion, 44F: First straight portion, 44S: Second straight portion, 48, 48A, 48B: U-shaped coil segment, 48C: connection part, 48S: straight section, 50: busbar unit, 52: first busbar case, 54: second busbar case, 56: cover, 61: first busbar group, 61A: first busbar, 62: second busbar group, 62A: second busbar, A1: central axis, D1: axial direction, D2: radial direction, D3: circumferential direction, H1, H2, H3: through hole, P1: first plane, P2: second plane

Claims

1. It is the stator of an electric motor, A stator core extending cylindrically along the axial direction between the first end face and the second end face, A plurality of slots are provided on the inner circumferential surface of the stator core, each extending in the axial direction and arranged along the circumferential direction of the stator core, A stator coil comprising multiple coil segments arranged in the multiple slots and multiple busbars, Equipped with, The stator coil has a first coil end portion that protrudes from the first end face of the stator core, Each of the aforementioned busbars connects the ends of two coil segments protruding from different slots at the first coil end portion. The plurality of busbars include a plurality of first busbars arranged on a first plane perpendicular to the axial direction, and a plurality of second busbars arranged on a second plane spaced apart from the first plane in the axial direction. Each of the plurality of first busbars intersects with a corresponding one of the plurality of second busbars when viewed along the axial direction. stata.

2. The plurality of first busbars have the same shape as each other and are arranged at equal intervals along the circumferential direction. The plurality of second busbars have the same shape as each other and are arranged at equal intervals along the circumferential direction. The stator according to claim 1.

3. The plurality of coil segments comprises a plurality of U-shaped coil segments and a plurality of I-shaped coil segments. Each of the plurality of I-shaped coil segments is connected at the first coil end portion to another of the plurality of I-shaped coil segments via the first busbar or the second busbar. The stator according to claim 1.

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

5. The first plane is closer to the first end face of the stator core than the second plane. Each of the plurality of U-shaped coil segments extends between two different slots between the first plane and the first end face of the stator core. The stator according to claim 1.

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