Rotating electric machine stator

Abstract

Disclosed is a rotating electric machine stator comprising a stator core and a winding. The winding includes: slot insertion portions; a first crossover portion connected to a pair of slot insertion portions of a first pitch, a second crossover portion connected to a pair of slot insertion portions of a second pitch larger than the first pitch, and a third crossover portion, on a first axial side; and a fourth crossover portion on a second axial side. In one coil portion for one phase, the first and second crossover portions are formed such that the radial position of an end part on the side closer to a power line is displaced to a first radial side with respect to the radial position of the end part on the side closer to the neutral point, the second crossover portion overlaps the first crossover portion over the entire circumferential direction of the first crossover portion when viewed in the axial direction, and the third crossover portion is formed such that the radial position of the end part on the side closer to the power line is displaced to a second radial side with respect to the radial position of the end part on the side closer to the neutral point.

Description

Stator for rotating electrical machine

[0001] The present disclosure relates to a stator for a rotating electric machine.

[0002] Regarding a stator for a rotating electric machine in which a plurality of coil sections electrically connected in parallel (parallel number = 4) are formed in each of three phases, a technology is known in which the winding wound by wave winding has a short-pitch crossover section connecting pairs of slot insertion sections inserted into slots at a pitch of 5 slots and a long-pitch crossover section connecting pairs of slot insertion sections inserted into slots at a pitch of 7 slots, and the long-pitch crossover section is arranged so as to cover the short-pitch crossover section from the axial outside.

[0003] JP 2016-152751 A

[0004] However, while the above-described conventional techniques are effective in reducing circulating currents, they have the following drawbacks. Specifically, this type of winding is formed by welding multiple coil segments together on one axial side. In this case, each of the transition sections arranged on the other axial side (non-welded side) has a configuration in which the radial position of the end closest to the power line in the circumferential direction is always shifted by one winding strand in the same radial direction relative to the radial position of the end closest to the neutral point in the circumferential direction. This configuration requires a separate special structure on the one axial side (welded side) to establish each transition section. This results in inconveniences, such as increased man-hours, when welding the coil segments together on the one axial side (welded side).

[0005] Therefore, in one aspect, the present disclosure aims to reduce the number of steps required to weld coil pieces together while reducing the circulating current.

[0006] According to one aspect, the present invention comprises: a stator core having teeth spaced equally in the circumferential direction; and a winding wound in a wave winding manner, the winding forming a plurality of coil sections in each phase electrically connected in parallel between a power line and a neutral point, the plurality of coil pieces forming the winding being joined by welding on a second axial side of the stator core, the winding having: a slot insertion portion inserted into a slot formed between adjacent teeth in the circumferential direction; a first crossover portion connected to a pair of slot insertion portions inserted into slots at a first slot pitch on a first axial side of the stator core opposite to the second axial side; a second crossover portion connected to a pair of slot insertion portions inserted into slots at a second slot pitch larger than the first slot pitch on the first axial side; a third crossover portion on the first axial side; and a plurality of fourth crossover portions on the second axial side of the stator core, and in one coil section for one phase, A stator for a rotating electric machine is provided, in which the first crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction; the second crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward the first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction, and overlaps the first crossover portion over the entire circumferential direction of the first crossover portion when viewed in the axial direction; and the third crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a second radial direction opposite the first radial side by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction.

[0007] According to one aspect of the present disclosure, it is possible to reduce the number of steps required to weld the coil pieces together while reducing the circulating current.

[0008] FIG. 1 is a plan view of a rotating electric machine (stator) according to the present embodiment. FIG. 2 is a circuit diagram of a Y-connected three-phase coil according to the present embodiment. FIG. 3 is a perspective view of a stator according to the present embodiment. FIG. 4 is a diagram for explaining the configuration of coil pieces forming a stator coil. FIG. 5 is a diagram for explaining the configuration of a U1 coil portion of a U-phase coil according to the present embodiment. FIG. 6 is a diagram for explaining the configuration of a U2 coil portion of a U-phase coil according to the present embodiment. FIG. 7 is a diagram for explaining the positional relationship between two specific jumper portions. FIG. 8 is a diagram for explaining the positional relationship between two specific medium-pitch jumper portions. FIG. 9 is a circuit diagram of a three-phase coil with "2Y connection". FIG. 10 is a diagram for explaining the configuration of a U1 coil portion of a U-phase coil according to a modified example. FIG. 11 is a diagram for explaining the configuration of a U2 coil portion of a U-phase coil according to a modified example. FIG. 12 is a diagram for explaining the configuration of a U3 coil portion of a U-phase coil according to a modified example. FIG. 13 is a diagram for explaining the configuration of a U4 coil portion of a U-phase coil according to a modified example.

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limiting. Furthermore, shapes and the like in the drawings may be partially exaggerated for the sake of explanation. Furthermore, in the drawings, for ease of viewing, reference symbols may be assigned only to some of the parts that exist with the same attribute.

[0010] FIG. 1 is a plan view of a rotating electrical machine (stator) according to this embodiment.

[0011] In this specification, "axial direction" refers to the direction along the rotation axis (symbol O) of the stator core 10 (rotor 150) (Z direction: see Figure 1). One side of the axial direction is referred to as the Z1 direction side, and the other side as the Z2 direction side. "Circumferential direction" refers to the circumferential direction (A direction) of the stator core 10. One side of the circumferential direction is referred to as the A1 direction, and the other side as the A2 direction. "Radial direction" refers to the radial direction (B direction) based on the rotation axis of the stator core 10 (rotor 150). "Radially inner" and "inner diameter side" refer to the direction toward the center of the stator core 10 (B1 direction). "Radially outer" and "outer diameter side" refer to the direction toward the outside of the stator core 10 (B2 direction).

[0012] As shown in FIG. 1 , the rotating electric machine 200 includes a stator 100 and a rotor 150. The stator 100 and the rotor 150 are each formed in an annular shape. The stator 100 and the rotor 150 face each other. The rotor 150 is disposed radially inward (on the B1 direction side) of the stator 100. The rotor 150 is provided with a plurality of permanent magnets (not shown). That is, the rotating electric machine 200 of this embodiment is configured as an inner rotor type rotating electric machine. The rotating electric machine 200 of this embodiment has eight magnetic poles, but the number of magnetic poles may be any number.

[0013] The stator 100 includes a stator core 10. The stator core 10 is disposed radially opposite the rotor 150. The stator core 10 includes a plurality of slots 11 (e.g., 48 slots). Teeth 12 are provided between adjacent slots 11. The stator core 10 includes, for example, a plurality of electromagnetic steel plates stacked in the direction of the rotation center axis (Z1 direction and Z2 direction), allowing magnetic flux to pass through. The stator core 10 may be formed by compression molding magnetic powder. The stator core 10 includes end faces 10a on both sides (Z1 direction) and (Z2 direction) in the axial direction. The stator 100 also includes a stator coil 20.

[0014] FIG. 2 is a circuit diagram of a three-phase coil in a Y-connection according to this embodiment.

[0015] 2, the stator coil 20 is connected to an external power supply and configured to receive power (e.g., three-phase AC power). The stator coil 20 is configured to generate a magnetic field when power is supplied. The stator coil 20 includes a U-phase coil 30, a V-phase coil 40, and a W-phase coil 50 through which three-phase (U-phase, V-phase, and W-phase) AC currents flow, respectively.

[0016] The U-phase coil 30 includes a U1 coil portion 31, a U2 coil portion 32, a U3 coil portion 33, and a U4 coil portion 34 connected in parallel. The V-phase coil 40 includes a V1 coil portion 41, a V2 coil portion 42, a V3 coil portion 43, and a V4 coil portion 44 connected in parallel. The W-phase coil 50 includes a W1 coil portion 51, a W2 coil portion 52, a W3 coil portion 53, and a W4 coil portion 54 connected in parallel. The U-phase coil 30, the V-phase coil 40, and the W-phase coil 50 are Y-connected (star-connected). That is, a so-called "4Y" connection is realized. AC power for the U-phase, V-phase, and W-phase is input from a power line terminal 61 to the U-phase coil 30, the V-phase coil 40, and the W-phase coil 50, respectively. The output sides of the U-phase coil 30 , the V-phase coil 40 , and the W-phase coil 50 are connected to one another via a neutral terminal 62 .

[0017] 3A and 3B are perspective views of the stator 100 according to the present embodiment. 3A is a diagram for explaining the configuration of the coil pieces 70 that form the stator coil 20. FIG.

[0018] As shown in FIG. 3 , the stator coil 20 is wound around the stator core 10. In this embodiment, the stator coil 20 is formed in a wave-wound configuration, with multiple coil pieces 70 ( FIG. 3A ) arranged in each of the multiple slots 11. Specifically, as shown in FIG. 3A , the stator coil 20 is formed as a wave-wound conductor by connecting multiple coil pieces 70. Note that each of the multiple coil pieces 70 may have an inverted U-shape when viewed with the Z1 side facing upward. Also, each of the multiple coil pieces 70 may be formed by covering a rectangular cross-section flat conductor wire with an insulating coating.

[0019] Each of the plurality of coil pieces 70 includes a slot insertion portion 21, a transition portion 22, and a portion of the welding-side transition portion 29 (an example of a leg portion).

[0020] The slot insertion portion 21 extends in the axial direction (Z direction) and is housed in each of the multiple slots 11 .

[0021] The transition portions 22 connect pairs of the multiple slot insertion portions 21 together. That is, the transition portions 22 connect the slot insertion portions 21 housed in different slots 11 (see FIG. 1 ). The transition portions 22 are formed on the Z1 direction side (an example of the first axial side). In this embodiment, on the Z1 direction side, the transition portions 22 have three types of configurations (short-pitch transition portions 23, long-pitch transition portions 24, and medium-pitch transition portions 25), as will be described later. Note that one transition portion 22 is formed by one coil piece 70.

[0022] The welding-side crossover portions 29 connect pairs of the slot insertion portions 21 together. The welding-side crossover portions 29 are formed by welding together a pair of leg portions 291 that continue from the slot insertion portions 21 and extend axially outward beyond the stator core 10. The welding-side crossover portions 29 are formed on the Z2 direction side (an example of the second axial side). That is, one crossover portion 22 is formed by two coil pieces 70 joined via welds 90. In this embodiment, the welds 90 between the coil pieces 70 are concentrated on the Z2 direction side. However, in a modified example, only the welding related to the power line terminals 61 and the neutral conductor terminals 62 may be performed on the Z1 direction side.

[0023] In the stator coil 20, the U-phase coil 30, the V-phase coil 40, and the W-phase coil 50 have substantially the same configuration. Therefore, the following description will mainly focus on the U-phase coil 30.

[0024] The U-phase coil 30 is arranged in the stator core 10 in such a manner that four sets of coils, a U1 coil portion 31, a U2 coil portion 32, a U3 coil portion 33, and a U4 coil portion 34, form a parallel circuit. One end of each of the U1 coil portion 31, the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34 is connected to a power line terminal 61. AC power is supplied from the power line terminal 61. The other end of each of the U1 coil portion 31, the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34 is connected to a neutral line terminal 62.

[0025] Fig. 4 is a diagram showing the configuration of the U1 coil portion 31 of the U-phase coil. Fig. 5 is a diagram showing the configuration of the U2 coil portion 32 of the U-phase coil. Fig. 6 is a diagram showing the configuration of the U3 coil portion 33 of the U-phase coil. Fig. 7 is a diagram showing the configuration of the U4 coil portion 34 of the U-phase coil. Fig. 8 is a diagram for explaining the positional relationship between two specific crossover portions 22. Fig. 9 is a diagram for explaining the positional relationship between two specific medium-pitch crossover portions 25.

[0026] As shown in Figures 4 to 7, the U1 coil portion 31, U2 coil portion 32, U3 coil portion 33, and U4 coil portion 34 of the U-phase coil 30 are each arranged in the fifth (hereinafter, "number" will be written as "#") slots 11 out of the 48 slots 11, namely, slots #5, #6, #11, #12, #17, #18, #23, #24, #29, #30, #35, #36, #41, #42, #47, and #48. Here, the slots 11 of #5 and #6, the slots 11 of #11 and #12, the slots 11 of #17 and #18, the slots 11 of #23 and #24, the slots 11 of #29 and #30, the slots 11 of #35 and #36, the slots 11 of #41 and #42, and the slots 11 of #47 and #48 are adjacent to each other in the circumferential direction (direction A). Note that FIGS. 4 to 7 are views showing the annular stator core 10 in an expanded form, with the up-down direction being the radial direction (direction B) of the stator core 10 and the left-right direction being the circumferential direction (direction A) of the stator core 10. That is, in FIGS. 4 to 7, the left and right ends of the figures are connected to each other. Although not shown, the V-phase coil 40 and the W-phase coil 50 are arranged in the stator core 10 so as to be offset by two and four slots 11, respectively, from the U-phase coil 30.

[0027] The multiple slot insertion portions 21 are housed in each of the multiple slots 11, lined up along the radial direction (direction B) of the stator core 10. Specifically, in this embodiment, six slot insertion portions 21 are arranged in a row in the radial direction in one slot 11. For example, in one slot 11, the slot insertion portion 21 arranged on the outermost side (outer diameter side: B2 direction) is the first turn (first layer), and the slot insertion portion 21 arranged on the innermost side (inner diameter side: B1 side) is the sixth turn (sixth layer). Note that in FIGS. 4 to 7 , the slot insertion portions 21 are arranged so that current (of the AC current, a current from the power supply to the U-phase coil 30) flows through the positions indicated by white numbers on a black background in the order of the white numbers. Hereinafter, the radial position of the first turn is represented by turn number = 1, the radial position of the second turn is represented by turn number = 2, and so on. 4 and other figures, the turn number is shown below the character "turn," and each square is divided into a turn number and a slot 11. In this embodiment, the number of turns is 6, but the number of turns may be any even number (for example, an even number equal to or greater than 4).

[0028] In this embodiment, the transition portions 22 have three types of shapes, which will be referred to below as short-pitch transition portions 23, long-pitch transition portions 24, and medium-pitch transition portions 25 when distinguishing between them. In Figures 4 to 7, the transition portions 22 (short-pitch transition portions 23, long-pitch transition portions 24, and medium-pitch transition portions 25) shown by solid lines are disposed on the Z1 direction side of the stator core 10, and the welding-side transition portions 29 shown by dashed lines are disposed on the Z2 direction side of the stator core 10. Furthermore, although Figures 4 to 7 schematically show the welding-side transition portions 29 as straight lines when viewed from the Z direction, the welding-side transition portions 29 may have a curved shape when viewed from the Z direction.

[0029] The short-pitch transition portions 23 connect pairs of slot insertion portions 21 that are inserted into the slots 11 at a five-slot pitch (an example of a first slot pitch) among the multiple slot insertion portions 21 housed in different slots 11. The short-pitch transition portions 23 also connect pairs of slot insertion portions 21 that are located at different radial positions (direction B). Specifically, the short-pitch transition portions 23 connect the slot insertion portions 21 so that the radial positions (turn numbers) of the connected slot insertion portions 21 change by one toward the radially outward side. That is, the short-pitch transition portions 23 connect pairs of slot insertion portions 21 so that the turn numbers decrease by one toward one circumferential side (direction A1). Hereinafter, increasing or decreasing the turn number by one in this manner will also be referred to as a “lane shift.” A lane shift in which the turn number increases circumferentially toward the A1 direction will also be referred to as a “radially inward lane shift,” and a lane shift in which the turn number decreases circumferentially toward the A1 direction will also be referred to as a “radially outward lane shift.” Such lane shifts have the function of changing the radial position (turn number) of the slot insertion portion 21 between one circumferential side and the other circumferential side.

[0030] The long pitch transition portions 24 connect pairs of slot insertion portions 21 that are inserted into the slots 11 at a seven-slot pitch (an example of a second slot pitch) among the multiple slot insertion portions 21 housed in different slots 11. Similarly to the short pitch transition portions 23, the long pitch transition portions 24 connect pairs of slot insertion portions 21 that are located at different radial positions (direction B). Specifically, the long pitch transition portions 24 connect the slot insertion portions 21 so that the radial positions (turn numbers) of the connected slot insertion portions 21 change by one toward the radially outward side. That is, the long pitch transition portions 24 connect pairs of slot insertion portions 21 so that the turn numbers decrease by one toward one circumferential side (direction A1).

[0031] The medium pitch crossover portions 25 connect pairs of slot insertion portions 21 that are inserted into the slots 11 at a six-slot pitch (an example of a third slot pitch) among the multiple slot insertion portions 21 housed in different slots 11. The medium pitch crossover portions 25 also connect pairs of slot insertion portions 21 that are located at different radial positions (direction B). Specifically, the medium pitch crossover portions 25 connect the slot insertion portions 21 so that the radial positions (turn numbers) of the connected slot insertion portions 21 change by one toward the radially inward direction. That is, the medium pitch crossover portions 25 connect pairs of slot insertion portions 21 so that the turn numbers increase by one toward one circumferential side (direction A1).

[0032] In the following, among the multiple coil pieces 70, the coil pieces 70 that form the short-pitch jumper section 23 will also be referred to as short-pitch coil pieces 71 when distinguishing them from the others, the coil pieces 70 that form the long-pitch jumper section 24 will also be referred to as long-pitch coil pieces 72 when distinguishing them from the others, and the coil pieces 70 that form the medium-pitch jumper section 25 will also be referred to as medium-pitch coil pieces 73 when distinguishing them from the others.

[0033] The welding-side jumper portion 29 has a weld portion 90 that joins two coil pieces 70 together. The welding-side jumper portion 29 connects pairs of slot insertion portions 21 that are inserted into the slots 11 at a pitch of six slots out of the multiple slot insertion portions 21 housed in different slots 11. Specifically, the welding-side jumper portion 29 connects the slot insertion portions 21 together so that the radial positions (turn numbers) of the connected slot insertion portions 21 change by one turn toward the radially inward side. In other words, the welding-side jumper portion 29 connects pairs of slot insertion portions 21 together so that the turn numbers increase by one turn toward one circumferential side (the A1 direction side).

[0034] In this embodiment, the welding-side jumper portion 29 is formed of short-pitch coil pieces 71 and long-pitch coil pieces 72. The welding-side jumper portion 29 is also formed of short-pitch coil pieces 71 and medium-pitch coil pieces 73. The welding-side jumper portion 29 is also formed of long-pitch coil pieces 72 and medium-pitch coil pieces 73. The welding-side jumper portion 29 is also formed of coil pieces 70 that form the power line terminal 61 at their end, the short-pitch coil pieces 71, and the long-pitch coil pieces 72. The welding-side jumper portion 29 is also formed of coil pieces 70 that form the neutral conductor terminal 62 at their end, the short-pitch coil pieces 71, and the long-pitch coil pieces 72.

[0035] In this embodiment, the U1 coil portion 31 of the U-phase coil 30 is wave-wound in a manner that always extends in the A1 direction from the power line terminal 61 toward the neutral conductor terminal 62, as shown in FIG. 4 . That is, there is no turning back in the A2 direction. Specifically, for the U1 coil portion 31, the coil piece 70 forming the power line terminal 61 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #42 slot 11 at the radial position of turn number 1, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the long-pitch coil piece 72. The coil piece 70 forming the neutral conductor terminal 62 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #47 slot 11, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the long-pitch coil piece 72. From the power line terminal 61 to the neutral line terminal 62, in the circumferential sections with turn numbers 1 and 2, the long-pitch coil pieces 72, the short-pitch coil pieces 71, and the long-pitch coil pieces 72 are connected in this order. At this time, on the Z1 direction side, the long-pitch crossover portion 24, the short-pitch crossover portion 23, and the long-pitch crossover portion 24 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (lane shift due to the welding-side crossover portion 29), thereby maintaining the turn number at 1 or 2. Then, when the turn number changes from 2 to 3, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is positioned. Next, in the circumferential sections with turn numbers 3 and 4, the short-pitch coil pieces 71, the long-pitch coil pieces 72, and the short-pitch coil pieces 71 are connected in this order. At this time, on the Z1 direction side, the short-pitch crossover portion 23, the long-pitch crossover portion 24, and the short-pitch crossover portion 23 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (the lane shift caused by the welding-side crossover portion 29), thereby maintaining the turn number at 3 or 4. Then, when the turn number changes from 4 to 5, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is arranged. In the circumferential sections with turn numbers 5 and 6, the long-pitch coil piece 72, the short-pitch coil piece 71, and the long-pitch coil piece 72 are connected in this order.At this time, on the Z1 direction side, the long pitch crossover section 24, the short pitch crossover section 23, and the long pitch crossover section 24 appear in sequence, and each cancels out the lane shift radially inward on the Z2 direction side (lane shift due to the welding side crossover section 29), thereby maintaining the turn number at 5 or 6.

[0036] As shown in FIG. 5 , the U2 coil portion 32 of the U-phase coil 30 is wave-wound so that it always extends in the A2 direction from the power line terminal 61 toward the neutral conductor terminal 62. That is, there is no turning back in the A1 direction. Specifically, for the U2 coil portion 32, the coil piece 70 forming the power line terminal 61 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #42 slot 11 at the radial position of turn number 6, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the short-pitch coil piece 71. The coil piece 70 forming the neutral conductor terminal 62 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #35 slot 11, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the short-pitch coil piece 71. From the power line terminal 61 to the neutral line terminal 62, in the circumferential sections with turn numbers 6 and 7, short-pitch coil pieces 71, long-pitch coil pieces 72, and short-pitch coil pieces 71 are connected in this order. At this time, on the Z1 direction side, short-pitch crossover portion 23, long-pitch crossover portion 24, and short-pitch crossover portion 23 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (lane shift due to the welding-side crossover portion 29), thereby maintaining the turn number at 5 or 6. Then, when the turn number changes from 5 to 4, a medium-pitch coil piece 73 that forms a medium-pitch crossover portion 25 is positioned. Next, in the circumferential sections with turn numbers 3 and 4, long-pitch coil pieces 72, short-pitch coil pieces 71, and long-pitch coil pieces 72 are connected in this order. At this time, on the Z1 direction side, the long-pitch crossover portion 24, the short-pitch crossover portion 23, and the long-pitch crossover portion 24 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (the lane shift caused by the welding-side crossover portion 29), thereby maintaining the turn number at 3 or 4. Then, when the turn number changes from 3 to 2, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is arranged. In the circumferential sections with turn numbers 1 and 2, the short-pitch coil piece 71, the long-pitch coil piece 72, and the short-pitch coil piece 71 are connected in this order.At this time, on the Z1 direction side, the short pitch crossover section 23, the long pitch crossover section 24, and the short pitch crossover section 23 appear in sequence, and each cancels out the lane shift radially inward on the Z2 direction side (lane shift due to the welding side crossover section 29), thereby maintaining the turn number at 1 or 2.

[0037] As shown in FIG. 6 , the U3 coil portion 33 of the U-phase coil 30 is wave-wound in a manner that always extends in the A1 direction from the power line terminal 61 toward the neutral conductor terminal 62. That is, there is no turning back in the A2 direction. Specifically, for the U3 coil portion 33, the coil piece 70 forming the power line terminal 61 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #41 slot 11 at the radial position of turn number 1, and forms a welding-side jumper portion 29 in cooperation with the short-pitch coil piece 71 on the Z2 direction. The coil piece 70 forming the neutral conductor terminal 62 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #48 slot 11, and forms a welding-side jumper portion 29 in cooperation with the short-pitch coil piece 71 on the Z2 direction. From the power line terminal 61 to the neutral line terminal 62, in the circumferential sections with turn numbers 1 and 2, the short-pitch coil pieces 71, the long-pitch coil pieces 72, and the short-pitch coil pieces 71 are connected in this order. At this time, on the Z1 direction side, the short-pitch crossover portion 23, the long-pitch crossover portion 24, and the short-pitch crossover portion 23 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (lane shift due to the welding-side crossover portion 29), thereby maintaining the turn number at 1 or 2. Then, when the turn number changes from 2 to 3, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is positioned. Next, in the circumferential sections with turn numbers 3 and 4, the long-pitch coil pieces 72, the short-pitch coil pieces 71, and the long-pitch coil pieces 72 are connected in this order. At this time, on the Z1 direction side, the long-pitch crossover portion 24, the short-pitch crossover portion 23, and the long-pitch crossover portion 24 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (the lane shift due to the welding-side crossover portion 29), thereby maintaining the turn number at 3 or 4. Then, when the turn number changes from 4 to 5, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is arranged. In the circumferential sections with turn numbers 5 and 6, the short-pitch coil piece 71, the long-pitch coil piece 72, and the short-pitch coil piece 71 are connected in this order.At this time, on the Z1 direction side, the short pitch crossover section 23, the long pitch crossover section 24, and the short pitch crossover section 23 appear in sequence, and each cancels out the lane shift radially inward on the Z2 direction side (lane shift due to the welding side crossover section 29), thereby maintaining the turn number at 5 or 6.

[0038] 7, the U4 coil portion 34 of the U-phase coil 30 is wave-wound in a manner that always extends in the A2 direction from the power line terminal 61 toward the neutral conductor terminal 62. That is, there is no turning back in the A1 direction. Specifically, for the U4 coil portion 34, the coil piece 70 forming the power line terminal 61 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #41 slot 11 at the radial position of turn number 6, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the long-pitch coil piece 72. The coil piece 70 forming the neutral conductor terminal 62 at its end has a slot insertion portion 21 inserted from the Z1 direction into the #36 slot 11, and forms a welding-side jumper portion 29 on the Z2 direction in cooperation with the long-pitch coil piece 72. From the power line terminal 61 to the neutral line terminal 62, in the circumferential sections with turn numbers 6 and 7, the long-pitch coil pieces 72, the short-pitch coil pieces 71, and the long-pitch coil pieces 72 are connected in this order. At this time, on the Z1 direction side, the long-pitch crossover portion 24, the short-pitch crossover portion 23, and the long-pitch crossover portion 24 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (lane shift due to the welding-side crossover portion 29), thereby maintaining the turn number at 5 or 6. Then, when the turn number changes from 5 to 4, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is positioned. Next, in the circumferential sections with turn numbers 3 and 4, the short-pitch coil pieces 71, the long-pitch coil pieces 72, and the short-pitch coil pieces 71 are connected in this order. At this time, on the Z1 direction side, the short-pitch crossover portion 23, the long-pitch crossover portion 24, and the short-pitch crossover portion 23 appear in this order, and each cancels out the lane shift toward the radially inward direction on the Z2 direction side (the lane shift caused by the welding-side crossover portion 29), thereby maintaining the turn number at 3 or 4. Then, when the turn number changes from 3 to 2, the medium-pitch coil piece 73 that forms the medium-pitch crossover portion 25 is arranged. In the circumferential sections with turn numbers 1 and 2, the long-pitch coil piece 72, the short-pitch coil piece 71, and the long-pitch coil piece 72 are connected in this order.At this time, on the Z1 direction side, the long pitch crossover section 24, the short pitch crossover section 23, and the long pitch crossover section 24 appear in sequence, and each cancels out the lane shift radially inward on the Z2 direction side (lane shift due to the welding side crossover section 29), thereby maintaining the turn number at 1 or 2.

[0039] In this embodiment, the range in which the power line terminal 61 and the neutral line terminal 62 are taken out can be kept within 120 degrees. That is, in the illustrated example, this is the circumferential range from slot 11 #35 to slot 11 #48, which is significantly smaller than the circumferential range of 18 slots.

[0040] In this embodiment, the U1 coil portion 31 and U3 coil portion 33 of the U-phase coil 30 have short-pitch coil pieces 71 and long-pitch coil pieces 72 that form a concentric coil when viewed in the radial direction. That is, the circumferential center position between the pair of slot insertion portions 21 formed by the short-pitch coil pieces 71 coincides with the circumferential center position between the pair of slot insertion portions 21 formed by the long-pitch coil pieces 72. In this case, as shown in FIG. 8 , the long-pitch crossover portion 24 is located axially outward of the short-pitch crossover portion 23, and overlaps the short-pitch crossover portion 23 when viewed in the axial direction. Similarly, the U2 coil portion 32 and U4 coil portion 34 of the U-phase coil 30 have short-pitch coil pieces 71 and long-pitch coil pieces 72 that form a concentric coil when viewed in the radial direction. That is, the long-pitch crossover portion 24, which has a larger slot pitch number, is located above (in the Z1 direction) the short-pitch crossover portion 23, which has a smaller slot pitch number. Specifically, the long-pitch crossover portion 24, which has a slot pitch of 7, is arranged to cover the upper side of the short-pitch crossover portion 23, which has a slot pitch of 5. Forming such a concentric coil reduces circulating current. Note that, for the U-phase, the circulating current refers to the current that circulates within the U-phase coil 30 through any of the U1 coil portion 31, U2 coil portion 32, U3 coil portion 33, and U4 coil. As the circulating current increases, loss increases.

[0041] Furthermore, in this embodiment, the medium-pitch coil pieces 73 of the U1 coil portion 31 and the U3 coil portion 33 of the U-phase coil 30 form non-concentric coils when viewed radially. That is, the circumferential center position between the pair of slot insertion portions 21 formed by the medium-pitch coil pieces 73 of the U1 coil portion 31 does not coincide with the circumferential center position between the pair of slot insertion portions 21 formed by the medium-pitch coil pieces 73 of the U1 coil portion 31 (they are offset by one slot). This is because the medium-pitch crossover portions 25 have the same six-slot pitch. In this case, the two medium-pitch crossover portions 25 are positioned circumferentially offset by one slot. In this case, the two medium-pitch crossover portions 25 can have the same shape. That is, medium-pitch coil pieces 73 of the same shape can be used. This reduces the number of types of coil pieces 70 required to form the stator coil 20. Furthermore, in this case, as shown in FIGS. 4 to 7 , the U1 coil portion 31 to the U4 coil portion 34 have at least one (more precisely, one or two) slot insertion portion 21 disposed in each of the slots 11 (#5, #6, #11, #12, #17, #18, #23, #24, #29, #30, #35, #36, #41, #42, #47, and #48) into which the U-phase coil 30 is inserted. This allows for good balance in the arrangement of the U-phase coils 30 disposed in each slot 11. The same applies to the V-phase coil 40 and the W-phase coil 50. Note that in this embodiment, the mid-pitch transition portions 25 forming the non-concentric coils are also positioned at the same axial outermost positions when arranged.

[0042] In this way, in this embodiment, two adjacent slots in a slot group forming one magnetic pole are filled with only coils of the same phase, and the coils constituting the parallel winding groups of the same phase are arranged in a balanced manner, thereby effectively reducing circulating current.

[0043] Furthermore, according to this embodiment, the transition portion disposed on the Z2 direction side of the stator core 10 can be realized using only the weld-side transition portion 29. That is, in this embodiment, the multiple coil pieces 70 forming the U1 coil portion 31 can form the weld-side transition portion 29 that realizes lane shifting in a fixed direction on the Z2 direction side of the stator core 10. This also applies to the multiple coil pieces 70 forming the U2 coil portion 32, the multiple coil pieces 70 forming the U3 coil portion 33, and the multiple coil pieces 70 forming the U4 coil portion 34. This configuration reduces the number of welding steps required to form the welded portion 90. Specifically, if both radially inward lane shifting and radially outward lane shifting were to occur on the Z2 direction side, the handling of the welding jig would become complicated, resulting in inconveniences such as increased man-hours. In contrast, in this embodiment, only radially inward lane shifting is realized on the Z2 direction side, thereby reducing the number of welding steps required.

[0044] Although the above-described embodiment illustrates a 4Y configuration (number of parallel connections = 4) as an example, this is not limiting. For example, a 2Y configuration may also utilize configurations similar to the winding diagrams shown in FIGS. 4 to 7 . In this case, the 2Y configuration can be achieved by connecting the power line terminal 61 of the U1 coil section 31 to the neutral line terminal 62 of the U2 coil section 32 with a crossover wire, and by connecting the power line terminal 61 of the U3 coil section 33 to the neutral line terminal 62 of the U4 coil section 34 with a crossover wire. FIG. 10 is a circuit diagram of a three-phase coil with a "2Y connection." The 2Y connection is essentially the same as the 4Y connection shown in FIG. 2 , except that the number of parallel connections is reduced by two. That is, the stator coil 20A includes a U-phase coil 30A, a V-phase coil 40A, and a W-phase coil 50A, through which three-phase (U-phase, V-phase, and W-phase) AC currents flow, respectively.

[0045] Next, a modification of the above-described embodiment will be described with reference to FIG. 11 and subsequent figures.

[0046] 11 to 14 are explanatory diagrams of this modified example, and are winding diagrams corresponding to FIGS. 4 to 7 of this embodiment.

[0047] In this modification, the U1 coil portion 31A corresponds to the U1 coil portion 31 according to the embodiment described above, the U2 coil portion 32A corresponds to the U2 coil portion 32 according to the embodiment described above, and so on.

[0048] 11 to 14, the present modification is different from the above-described embodiment in that it does not use the medium-pitch crossover portion 25 (medium-pitch coil pieces 73). That is, in this modification, the crossover portion on the Z1 direction side is made up of a short-pitch crossover portion 23, a long-pitch crossover portion 24, a short-pitch crossover portion 26, and a long-pitch crossover portion 27.

[0049] The short pitch crossover portion 26 has a five-slot pitch like the short pitch crossover portion 23, but the direction of lane shifting is different from that of the short pitch crossover portion 23. That is, the short pitch crossover portion 26 achieves lane shifting in the same manner as the medium pitch crossover portion 25 of the above-described embodiment.

[0050] Specifically, the short pitch transition portions 26 connect pairs of slot insertion portions 21 that are inserted into the slots 11 at a five-slot pitch, among the multiple slot insertion portions 21 housed in different slots 11. The short pitch transition portions 26 also connect pairs of slot insertion portions 21 that are located at different radial positions (direction B). The short pitch transition portions 26 connect pairs of slot insertion portions 21 so that the turn number increases by one toward one circumferential side (direction A1). In other words, the short pitch transition portions 26 realize lane shifting toward the radially inward direction.

[0051] The long pitch crossover portion 27 has a seven-slot pitch like the long pitch crossover portion 24, but the direction of lane shift is different from that of the long pitch crossover portion 24. That is, the long pitch crossover portion 27 achieves lane shifting in the same manner as the medium pitch crossover portion 25 of the above-described embodiment.

[0052] Specifically, the long pitch transition portions 27 connect pairs of slot insertion portions 21 that are inserted into slots 11 at a seven-slot pitch among the multiple slot insertion portions 21 housed in different slots 11. The long pitch transition portions 27 also connect pairs of slot insertion portions 21 that are located at different radial positions (direction B). The long pitch transition portions 27 connect pairs of slot insertion portions 21 so that the turn number increases by one toward one circumferential side (direction A1). In other words, the short pitch transition portions 26 realize lane shifting radially inward.

[0053] In this modified example, the long pitch crossover portion 27 of the U1 coil portion 31A and the short pitch crossover portion 26 of the U3 coil portion 33A are arranged in the same relationship as the long pitch crossover portion 24 and the short pitch crossover portion 23 shown in Fig. 8. Similarly, the short pitch crossover portion 26 of the U2 coil portion 32A and the long pitch crossover portion 27 of the U4 coil portion 34A are arranged in the same relationship as the short pitch crossover portion 23 and the long pitch crossover portion 24 shown in Fig. 8.

[0054] This modification also provides the same effects as the above-described embodiment. However, as can be seen by comparing this modification with the winding diagrams of the above-described embodiment shown in Figures 4 to 7, it is inferior to the above-described embodiment in terms of the layout balance and the types of coil pieces 70, as shown in Figures 11 to 14. For example, with regard to the layout balance, as shown in Figures 11 to 14, the U1 coil section 31A to U4 coil section 34A have three slot insertion sections 21 arranged in only half of each of the slots 11 (#5, #6, #11, #12, #17, #18, #23, #24, #29, #30, #35, #36, #41, #42, #47, and #48) into which the U-phase coil 30 is inserted. Therefore, the layout balance of the U-phase coil 30 arranged in each slot 11 is slightly inferior to the above-described embodiment.

[0055] Although each embodiment has been described in detail above, it is not limited to the specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments.

[0056] For example, in the above-described embodiment (and the same applies to the modified example), the short-pitch crossover portion 23 and the long-pitch crossover portion 24 realize lane shifting radially outward, and the long-pitch crossover portion 27 realizes lane shifting radially inward, but the opposite may also be true. That is, the short-pitch crossover portion 23 and the long-pitch crossover portion 24 may realize lane shifting radially inward, and the long-pitch crossover portion 27 may realize lane shifting radially outward. In this case, the weld-side crossover portion 29 may realize lane shifting radially outward.

[0057] Furthermore, the following notes are disclosed regarding the above embodiment.

[0058] [Note 1] A stator core having teeth at equal intervals in the circumferential direction and having slots formed between adjacent teeth in the circumferential direction; and a winding wound in a wave winding manner, the winding forming a plurality of coil portions in each phase that are electrically connected in parallel between a power line and a neutral point, the plurality of coil pieces forming the winding comprising a pair of slot insertion portions inserted into the slots that are spaced at a predetermined pitch in the circumferential direction, a coil end portion connecting the pair of slot insertion portions to one side of the stator core in the axial direction, and leg portions extending from the pair of slot insertion portions to the other side of the stator core in the axial direction, the winding being formed by electrically connecting the leg portions of the coil pieces to each other, the coil end portion comprising: a first crossover portion connecting the pair of slot insertion portions to each other at a first slot pitch; and a second crossover portion connecting the pair of slot insertion portions to each other at a second slot pitch that is larger than the first slot pitch. and a third crossover portion connecting the pair of slot insertion portions at a predetermined slot pitch, wherein in one coil portion for one phase, the first crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction, the second crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward the first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction, and the third crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a second radial direction opposite to the first radial side by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction.

[0059] [Appendix 2] A stator for a rotating electric machine as described in Appendix 1, wherein in at least two of the coil sections connected in parallel to each other for one phase, the second crossover section overlaps the first crossover section over the entire circumferential direction of the first crossover section when viewed in the axial direction.

[0060] [Appendix 3] A stator for a rotating electric machine according to Appendix 1 or 2, wherein the third crossover portion connects the pair of slot insertion portions at a third slot pitch that is longer than the first slot pitch and shorter than the second slot pitch, the coil portion for one phase including at least a first coil portion and a second coil portion connected in parallel to each other includes the third crossover portion having the same shape, the third crossover portion of the first coil portion and the third crossover portion of the second coil portion are arranged in a circumferential range where they partially overlap each other, and the slot insertion portion of the pair of slot insertion portions connected to the third crossover portion of the first coil portion on one circumferential side is inserted into a slot that is circumferentially shifted at the same radial position as the slot insertion portion of the pair of slot insertion portions connected to the third crossover portion of the second coil portion on the one circumferential side.

[0061] [Appendix 4] The stator for a rotating electric machine according to any one of Appendices 1 to 3, wherein the windings have a parallel number of 2 or 4, a phase number of 3, and an even number of turns of 4 or more, only windings of the same phase are inserted into two adjacent slots, and the two slots for the U phase, the two slots for the V phase, and the two slots for the W phase are arranged at equal intervals in the circumferential direction.

[0062] [Supplementary Note 5] The leg portion forms a plurality of fourth crossover portions, and the plurality of coil pieces include first coil pieces forming the first crossover portion, second coil pieces forming the second crossover portion, and third coil pieces forming the third crossover portion, and the third coil pieces have an end on one circumferential side joined to the first coil piece and an end on the other circumferential side joined to the second coil piece, and other first coil pieces and other second coil pieces are alternately joined circumferentially between the first coil piece joined to the third coil piece and the second coil piece joined to the third coil piece, and in one coil portion related to one phase, each of the fourth crossover portions has a configuration in which the radial position of the end portion closer to a power line in the circumferential direction is always shifted toward the second radial direction by the amount of one winding relative to the radial position of the end portion closer to a neutral point in the circumferential direction.

[0063] 100... Stator (stator for rotating electrical machine), 10... Stator core, 20... Stator coil (winding), 31... U1 coil portion (coil portion, first coil portion), 32... U2 coil portion (coil portion, first coil portion), 33... U3 coil portion (coil portion, second coil portion), 34... U4 coil portion (coil portion, second coil portion), 11... Slot, 21... Slot insertion portion, 23... Short pitch jumper portion (first jumper portion), 24... Long pitch jumper portion (second jumper portion), 25... Medium pitch jumper portion (third jumper portion), 26... Short pitch jumper portion (third jumper portion), 27 Long pitch jumper portion (third jumper portion), 29: welding side jumper portion (fourth jumper portion), 61: power line terminal (power line), 62: neutral line terminal (neutral point), 70: coil piece, 71: short pitch coil piece (first coil piece), 72: long pitch coil piece (second coil piece), 73: medium pitch coil piece (third coil piece).

Claims

1. A stator core having teeth spaced equally apart in the circumferential direction and having slots formed between adjacent teeth in the circumferential direction; and a winding wound in a wave winding manner, the winding forming a plurality of coil sections in each phase that are electrically connected in parallel between a power line and a neutral point, the plurality of coil pieces forming the winding having a pair of slot insertion sections inserted into the slots that are spaced at a predetermined pitch in the circumferential direction, a coil end section connecting the pair of slot insertion sections on one axial side of the stator core, and leg sections extending from the pair of slot insertion sections to the other axial side of the stator core, the winding being formed by electrically connecting the leg sections of the coil pieces together, the coil end section having: a first crossover section connecting the pair of slot insertion sections at a first slot pitch; and a second crossover section connecting the pair of slot insertion sections at a second slot pitch that is larger than the first slot pitch. and a third crossover portion connecting the pair of slot insertion portions at a predetermined slot pitch, wherein in one coil portion for one phase, the first crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction, the second crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward the first radial direction by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction, and the third crossover portion has a configuration in which the radial position of the end portion closer to the power line in the circumferential direction is shifted toward a second radial direction opposite to the first radial side by one winding relative to the radial position of the end portion closer to the neutral point in the circumferential direction.

2. A stator for a rotating electric machine as described in claim 1, wherein in at least two of the coil sections connected in parallel to each other for one phase, the second crossover section overlaps the first crossover section over the entire circumferential direction of the first crossover section when viewed in the axial direction.

3. A stator for a rotating electric machine as set forth in claim 1, wherein the third crossover portion connects the pair of slot insertion portions at a third slot pitch that is longer than the first slot pitch and shorter than the second slot pitch, the coil portion for one phase, which includes at least a first coil portion and a second coil portion connected in parallel to each other, includes the third crossover portion having the same shape, the third crossover portion of the first coil portion and the third crossover portion of the second coil portion are arranged in a circumferential range where they partially overlap each other, and the slot insertion portion on one circumferential side of the pair of slot insertion portions connected to the third crossover portion of the first coil portion is inserted into a slot that is circumferentially shifted at the same radial position as the slot insertion portion on one circumferential side of the pair of slot insertion portions connected to the third crossover portion of the second coil portion.

4. A stator for a rotating electric machine as set forth in claim 1, wherein the windings have a parallel number of 2 or 4, a phase number of 3, and an even number of turns of 4 or more, and only windings of the same phase are inserted into two adjacent slots, and the two slots relating to the U phase, the two slots relating to the V phase, and the two slots relating to the W phase are arranged at equal intervals in the circumferential direction.

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