Stator for rotating electrical machine

Abstract

To reduce an axial size of a stator while the number of parallel coil parts of each phase is four or more.SOLUTION: A stator for a rotary electric machine comprises: a stator coil whose coil part related to each phase is connected between a neutral line terminal and a power line terminal of each phase so as to form four or more sets of parallel circuits; and a stator core around which the stator coil is wound, having a plurality of slots. The stator coil has: a slot insertion part inserted into each corresponding slot among the plurality of slots; and a crossover part exposed from an axial end surface of the stator core and extending in a circumferential direction in a form connecting between a pair of slot insertion parts. In each phase, the plurality of slot insertion parts in each set include a first slot insertion part connected directly to the power line terminal. The first slot insertion part of each phase is located at the outermost diameter side of the corresponding slot, on an axial one side of the stator core.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A technique is known in which one end of each of a plurality of coil pieces forming a stator coil is positioned on the outermost side of the stator core within the slot, and the other end is positioned on the innermost side of the stator core within the slot. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-201485 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described conventional technology, it is necessary to route the wiring from the end of the innermost coil piece (e.g., the power line terminal) radially outward from the axially outer side of the coil end (i.e., it is necessary to straddle the coil end in the radial direction), which tends to increase the axial size of the stator coil. In particular, when the number of parallel coil parts for each phase is four or more, such a radially inner terminal arrangement is likely to be adopted due to the large number of terminals.

[0005] Therefore, in one aspect, an object of the present disclosure is to reduce the axial size of the stator while making the number of parallel-connected coil portions of each phase four or more. [Means for solving the problem]

[0006] In one aspect, a stator coil in which coil portions for each phase are connected between a neutral terminal and a power line terminal for each phase in four or more parallel circuits; a stator core having a plurality of slots and around which the stator coil is wound, The stator coil is a slot insertion portion to be inserted into each corresponding slot among the plurality of slots; a bridge portion that is exposed from an axial end face of the stator core and extends in a circumferential direction so as to connect the pair of slot insertion portions, A stator for a rotating electric machine is provided in which, in each phase, a first slot insertion portion of the plurality of slot insertion portions in each set that is directly connected to the power line terminal is located on one axial side of the stator core, on the outermost diameter side of the corresponding slot. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, it is possible to reduce the axial size of the stator while making the number of parallel coil portions for each phase four or more. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view of a rotating electric machine (stator) according to an embodiment of the present invention; [Figure 2] FIG. 1 is a circuit diagram of a Y-connected three-phase coil according to the present embodiment. [Figure 3] FIG. 2 is a perspective view of a stator according to the present embodiment. [Figure 3A] FIG. 2 is a side view of the stator according to the present embodiment. [Figure 3B] FIG. 2 is a top view of the stator according to the present embodiment. [Figure 3C] 3A and 3B are diagrams for explaining the configuration of coil pieces that form the stator coil. [Figure 4] 10 is a diagram showing the configuration of a U1 coil of a U-phase coil. FIG. [Figure 5] 10 is a diagram showing the configuration of a U2 coil of a U-phase coil. FIG. [Figure 6] 10 is a diagram showing the configuration of a U3 coil of a U-phase coil. FIG. [Figure 7] 10 is a diagram showing the configuration of the U4 coil of the U-phase coil. FIG. [Figure 8]FIG. 4 is a diagram showing the arrangement of each terminal of a U-phase coil. [Figure 9A] 10 is a diagram illustrating a second transition portion that connects slot insertion portions of the first turn on the outermost radial side in the radial direction. FIG. [Figure 9B] 10 is a view for explaining a third connecting portion that connects slot insertion portions of eighth turns on the innermost radial side in the radial direction. FIG. [Figure 10] FIG. 10 is a perspective view of a stator according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[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 Fig. 1 (and the same applies to Fig. 3 and subsequent figures), for ease of viewing, reference symbols may be assigned only to some of the same components that exist multiple times.

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

[0011] In this specification, the term "axial direction" refers to the direction along the rotation axis (symbol O) of the stator core 10 (rotor 150) (Z direction: see FIG. 1). One side of the axial direction is referred to as the Z1 direction side, and the other side as the Z2 direction side. The term "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. The term "radial direction" refers to the radial direction (B direction) based on the rotation axis of the stator core 10 (rotor 150). The terms "radially inner" and "inner diameter side" refer to the direction toward the center of the stator core 10 (B1 direction). The terms "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.

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

[0014] FIG. 2 is a circuit diagram of a Y-connected three-phase coil 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 to the U-phase coil 30, the V-phase coil 40, and the W-phase coil 50, respectively, from power line terminals 61. 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] Fig. 3 is a perspective view of the stator 100 according to this embodiment. Fig. 3A is a side view of the stator 100 according to this embodiment. Fig. 3B is a top view of the stator 100 according to this embodiment. Fig. 3C is a diagram for explaining the configuration of the coil pieces 70 that form the stator coil 20.

[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. 3C) arranged in each of the multiple slots 11. Specifically, as shown in FIG. 3C, the stator coil 20 is formed as a wave-wound conductor wire by connecting multiple coil pieces 70. Each of the multiple coil pieces 70 may have an inverted U-shape when viewed with the Z1 side facing upward. Each of the multiple coil pieces 70 may also 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 and a transition portion 22 .

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

[0021] The transition sections 22 connect pairs of the multiple slot insertion sections 21 together. That is, the transition sections 22 connect the slot insertion sections 21 housed in different slots 11. The transition sections 22 are formed on the Z2 direction side and the Z1 direction side, respectively. The shapes of the transition sections 22 differ for each of a first transition section 23, a second transition section 24, and a third transition section 25, which will be described later.

[0022] As shown in Figure 3C, after the coil pieces 70 are arranged so that the slot insertion portions 21 are accommodated in each of the slots 11, the jumper portions 22 on the Z2 direction side may be bent outward in the circumferential direction and joined to the jumper portions 22 on the Z2 direction side of different coil pieces 70 by laser joining or the like.

[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 on 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 illustrating the configuration of the U1 coil portion 31 of the U-phase coil. FIG. 5 is a diagram illustrating the configuration of the U2 coil portion 32 of the U-phase coil. FIG. 6 is a diagram illustrating the configuration of the U3 coil portion 33 of the U-phase coil. FIG. 7 is a diagram illustrating the configuration of the U4 coil portion 34 of the U-phase coil. FIG. 8 is a diagram illustrating the arrangement of each terminal (power line terminal 61 and neutral line terminal 62) related to the U-phase coil 30, illustrating only a portion of the outermost diameter side of the U-phase coil 30 (one turn portion on the outermost diameter side in the radial direction). FIG. 9A is a diagram illustrating the second crossover portion 24 that connects the slot insertion portions of the first turn on the outermost diameter side in the radial direction. FIG. 9B is a diagram illustrating the third crossover portion 25 that connects the slot insertion portions of the eighth turn on the innermost diameter side in the radial direction.

[0026] As shown in Figures 4 to 7, the U1 coil section 31, U2 coil section 32, U3 coil section 33, and U4 coil section 34 of the U-phase coil 30 are each arranged in slots 11 #1 (hereinafter, "number" will be written as "#"), #6, #7, #12, #13, #18, #19, #24, #25, #30, #31, #36, #37, #42, #43, and #48 of the 48 slots 11. Here, slots 11 #1 and #48, slots 11 #6 and #7, slots 11 #12 and #13, slots 11 #18 and #19, slots 11 #24 and #25, slots 11 #30 and #31, slots 11 #36 and #37, and slots 11 #42 and #43 are adjacent to each other in the circumferential direction (direction A). FIGS. 4 to 7 show the annular stator core 10 in a developed form, with the up-down direction corresponding to the radial direction (direction B) of the stator core 10 and the left-right direction corresponding to 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 slots 11 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 and lined up along the radial direction (direction B) of the stator core 10. Specifically, in this embodiment, eight 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 side) is the first turn (first layer), and the slot insertion portion 21 arranged on the innermost side (inner diameter side: B1 side) is the eighth turn (eighth 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.

[0028] In this embodiment, the crossover portion 22 has a first crossover portion 23, a second crossover portion 24, and a third crossover portion 25. In FIGS. 4 to 7, the crossover portions 22 (first crossover portion 23, second crossover portion 24, and third crossover portion 25) shown by solid lines are arranged on the Z1 direction side of the stator core 10, and the crossover portion 22 (first crossover portion 23) shown by dashed lines is arranged on the Z2 direction side of the stator core 10. Furthermore, in FIGS. 4 to 7, the crossover portions 22 (first crossover portion 23, second crossover portion 24, and third crossover portion 25) are schematically illustrated as straight lines when viewed from the Z direction, but the crossover portions 22 (first crossover portion 23, second crossover portion 24, and third crossover portion 25) may have a curved shape when viewed from the Z direction.

[0029] The first crossover portions 23 connect pairs of slot insertion portions 21 that are located at different radial positions (direction B) among the multiple slot insertion portions 21 housed in different slots 11. Specifically, the first crossover portions 23 connect the slot insertion portions 21 so that the radial positions (number of turns) of the connected slot insertion portions 21 change stepwise sequentially toward one radial side. That is, the first crossover portions 23 connect pairs of slot insertion portions 21 so that the number of turns increases toward one circumferential side (direction A1). The first crossover portions 23 and the slot insertion portions 21 form four wave winding portions 20a, 20b, 20c, and 20d that are each wave wound around the stator core 10.

[0030] In this embodiment, in each of the wave winding portions 20a to 20d, the multiple first crossover portions 23 and the slot insertion portions 21 are connected to sequentially connect the slot insertion portions 21 arranged on the outermost diameter side (first turn) to the slot insertion portions 21 arranged on the innermost diameter side (eighth turn). That is, the multiple first crossover portions 23 connect pairs of the slot insertion portions 21 so that the radial positions of the connected slot insertion portions 21 change stepwise from the slot insertion portion 21 arranged at the first turn position, which is the end on the other radial side (e.g., the B2 direction side) of the slot 11, to the slot insertion portion 21 arranged at the eighth turn position, which is the end on one side (e.g., the B1 direction side). In this embodiment, the first crossover portions 23 connect pairs of the slot insertion portions 21 arranged in different slots 11, which are shifted radially outward or inward by one. That is, in each of the wave winding portions 20a to 20d, the first crossover portion 23 connects the slot insertion portions 21 while being shifted by one turn in order from the eighth turn to the first turn.

[0031] The wave winding portions 20a to 20d are provided so as to make at least one round trip (two round trips in this embodiment). One wave winding portion 20a is wave-wound along one side in the circumferential direction of the stator core 10 (for example, the A1 direction) by the slot insertion portion 21 and the first crossover portion 23. The wave winding portion 20b connected to the wave winding portion 20a is wave-wound along the other side in the circumferential direction (for example, the A2 direction) opposite to the wave winding portion 20a. The wave winding portions 20c and 20d are similarly wave-wound towards one side and the other side in the circumferential direction, respectively. The wave winding portion 20a, the wave winding portion 20b, the wave winding portion 20c, and the wave winding portion 20d are connected in this order to form the U1 coil portion 31, the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34 of the U-phase coil 30 in the stator coil 20. That is, the U1 coil portion 31, the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34 are each arranged on the stator core 10 while folding back three times in the circumferential direction.

[0032] In this embodiment, the wave winding portions 20a to 20d are connected to one another by either the second crossover portion 24 or the third crossover portion 25. The second crossover portion 24 and the third crossover portion 25 each connect pairs of slot insertion portions 21 that are housed in different slots 11 and have the same radial position (number of turns). Specifically, the second crossover portion 24 connects the slot insertion portions 21 that are located at the outermost radial positions (first turn) in each of the multiple slots 11. The third crossover portion 25 connects the slot insertion portions 21 that are located at the innermost radial positions (eighth turn) in each of the multiple slots 11. The second crossover portion 24 or the third crossover portion 25 connects pairs of slot insertion portions 21 to one another, thereby connecting one end of one round trip of the wave winding portions 20a to 20d formed by the first crossover portion 23 and the slot insertion portions 21 in a folded-back manner. For example, in the U1 coil portion 31, four wave winding portions 20a to 20d, one second crossover portion 24, and two third crossover portions 25 form one conductor that is wave wound by being folded back multiple times.

[0033] Specifically, as shown in FIG. 4 , in the U1 coil portion 31, a power line terminal 61 is connected to the slot insertion portion 21 (the portion marked with the white numeral 1) located on the outermost diameter side (first turn) of the slot 11 of #37. The power line terminal 61 may be in the form of an end portion of the coil piece 70, or may be in the form of a separate member joined to the end portion of the coil piece 70. The slot insertion portion 21 extends in the Z2 direction along the slot 11, and then a first crossover portion 23 extends from #37 to #31 as a crossover portion 22 on the Z2 direction side. On the Z2 direction side of the stator core 10, the first crossover portion 23 is connected to the slot insertion portion 21 (the portion marked with the numeral 2) located in the second turn of the slot 11 of #31, shifted inward from the outermost diameter side. Thereafter, the first crossover portion 23 is connected to the slot insertion portion 21 alternately on the Z1 direction side and the Z2 direction side in the order of the third turn of slot 11 of #25, the fourth turn of slot 11 of #19, and the fifth turn of slot 11 of #13, and is connected up to the slot insertion portion 21 of the eighth turn (portion numbered 8) of slot 11 of #43 while increasing the number of turns inward by one. In this way, a wave winding portion 20a connected by eight slot insertion portions 21 and seven first crossover portions 23 is formed.

[0034] A third crossover portion 25 is provided so as to fold back on the Z1 direction side of the stator core 10 from the slot insertion portion 21 of the eighth turn of the #43 slot 11 (the portion marked with the white numeral 8) to the slot insertion portion 21 of the eighth turn of the #48 slot 11 (the portion marked with the numeral 9). After being folded back by the third crossover portion 25, the wave winding portion 20b is formed in the same manner as the wave winding portion 20a from the #48 slot 11 where the portion marked with the numeral 9 is provided toward the A2 direction in the circumferential direction to the #42 slot 11. The U1 coil portion 31 is then folded back from the wave winding portion 20b to the wave winding portion 20c by providing a second crossover portion 24 on the Z1 direction side of the stator core 10 from the slot insertion portion 21 of the first turn of the #42 slot 11 (the portion marked with the numeral 16) to the slot insertion portion 21 of the first turn of the #1 slot 11 (the portion marked with the numeral 17). Thereafter, the U1 coil portion 31 is similarly folded back from the wave winding portion 20c to the wave winding portion 20d by the third crossover portion 25. In this way, one U1 coil portion 31 is formed by the four wave winding portions 20a to 20d folded back three times. Note that a neutral conductor terminal 62 is connected to the wave winding portion 20d from the slot insertion portion 21 (portion numbered 32) of the first turn of the #6 slot 11. Note that the neutral conductor terminal 62 may be in the form of an end portion of the coil piece 70, or may be in the form of a separate member joined to the end portion of the coil piece 70.

[0035] In this way, the first crossover section 23 connects the second turn to the third turn, the fourth turn to the fifth turn, and the sixth turn to the seventh turn, and is arranged on the Z1 direction side. Also, the second crossover section 24 connecting the first turns and the third crossover section 25 connecting the eighth turns are all arranged on the Z1 direction side. The power line terminal 61 and the neutral line terminal 62 are also connected on the Z1 direction side.

[0036] Hereinafter, of the multiple slot insertion portions 21, the slot insertion portion 21 directly connected to the power line terminal 61 (in the U1 coil portion 31, the slot insertion portion 21 inserted into the slot 11 #37) will be referred to as the “first slot insertion portion 21A” when distinguishing it from the other slot insertion portions 21. Furthermore, of the multiple slot insertion portions 21, the slot insertion portion 21 directly connected to the neutral terminal 62 (the slot insertion portion 21 inserted into the slot 11 #6) will be referred to as the “second slot insertion portion 21B” when distinguishing it from the other slot insertion portions 21. Furthermore, of the multiple slot insertion portions 21, the slot insertion portion 21 inserted at the innermost diameter side of the slot 11 (the eighth turn) (the slot insertion portions 21 inserted into the slots 11 #7, #12, #43, and #48) will be referred to as the “third slot insertion portion 21C” when distinguishing it from the other slot insertion portions 21.

[0037] In this embodiment, as described above, each slot insertion section 21 along the current flow direction from the first slot insertion section 21A to the second slot insertion section 21B is inserted into the corresponding slot 11 in such a manner that the change trend (increase and decrease) of the slot number is reversed at least once (three times in this example). The "slot number" here refers to a relative increase in order clockwise or counterclockwise around the stator core 10 in the circumferential direction as viewed in the axial direction. In this embodiment, if #1 to #48 correspond to slot numbers, the direction in which the number increases by one from #1 to #48 corresponds to the direction in which the slot number increases, and the direction in which the number changes from #48 to #1 also corresponds to the direction in which the slot number increases. Furthermore, the direction in which the number decreases by one from #48 to #1 corresponds to the direction in which the slot number decreases, and the direction in which the number changes from #1 to #48 also corresponds to the direction in which the slot number decreases.

[0038] In particular, in this embodiment, in each of the U1 coil section 31, U2 coil section 32, U3 coil section 33, and U4 coil section 34, the slot numbers of the respective slot insertion sections 21 along the current flow direction from the first slot insertion section 21A to the second slot insertion section 21B are increased or decreased in reverse starting from the third slot insertion section 21C. For example, in the case of the U1 coil section 31, the slot numbers are decreased from the first slot insertion section 21A to the first third slot insertion section 21C (the slot insertion section 21C inserted into slot 11 #43) along the current flow direction, and the slot numbers are increased from the last third slot insertion section 21C (the slot insertion section 21C inserted into slot 11 #12) to the second slot insertion section 21B along the current flow direction.

[0039] In this embodiment, in each of the U1 coil section 31, U2 coil section 32, U3 coil section 33, and U4 coil section 34, the radial position of each slot insertion section 21 along the current flow direction from the first slot insertion section 21A to the second slot insertion section 21B changes regularly. For example, in the case of the U1 coil section 31, when the slot number decreases, the radial position within the slot 11 shifts radially inward by one turn (see the first crossover section 23). When the slot number increases, the radial position within the slot shifts radially outward by one turn (see the first crossover section 23) or the same radial position is maintained (see the second crossover section 24 and the third crossover section 25).

[0040] As shown in Figures 5 to 7, each of the U2 coil section 32, U3 coil section 33, and U4 coil section 34, like the U1 coil section 31, is configured as part of the stator coil 20, which is wave-wound by folding back four wave winding sections 20a to 20d multiple times.

[0041] In particular, in this embodiment, the power line terminal 61 and the neutral line terminal 62 of each of the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34 are disposed radially outward, similar to the U1 coil portion 31. That is, as shown in FIG. 8, the power line terminals 61 and the neutral line terminals 62 of each phase are all disposed radially outward of the stator core 10. Note that in FIG. 8, the symbols U, V, and W represent each phase, and the numbers 1 to 4 following the symbols U, V, and W represent the corresponding one of the four pairs. For example, U1 to U4 represent the U1 coil portion 31, the U2 coil portion 32, the U3 coil portion 33, and the U4 coil portion 34, respectively. Furthermore, the final "_in" and "_out" represent the power line terminal 61 and the neutral line terminal 62, respectively.

[0042] In this embodiment, in the U-phase coil 30, the power line terminals 61 for the U1 coil portion 31 and the U2 coil portion 32 and the power line terminals 61 for the U3 coil portion 33 and the U4 coil portion 34 are set at diagonal positions in the circumferential direction, as shown in Fig. 3B. This also applies to the V-phase coil 40 and the W-phase coil 50.

[0043] In this embodiment, the first crossover portions 23 forming one of the wave winding portions 20a to 20d and the first crossover portions 23 forming the other of the wave winding portions 20a to 20d connect the slot insertion portions 21 in pairs so that the radial positions of the connected slot insertion portions 21 change stepwise (in a sloped manner) parallel to each other. The number of slots 11 spanned by the first crossover portions 23 is the same in each of the wave winding portions 20a to 20d. Specifically, the first crossover portions 23 connect the slot insertion portions 21 by spanning five slots 11 while connecting the slot insertion portions 21 by shifting them by one turn. In other words, the pitch number of the first crossover portions 23 is "6" in each of the wave winding portions 20a to 20d. The first crossover portions 23 have a common pitch on one side (Z1 direction side) and the other side (Z2 direction side) of the stator core 10. Note that "parallel" here means that the radial positions of the slot insertion portions 21 connected to the first crossover portions 23 are parallel in a state where they are arranged along the circumferential direction. In other words, this means that the positions of the slot insertion portions 21 are parallel in a state where the annular stator core 10 is shown in an expanded form as shown in Figures 4 to 7.

[0044] Note that there are two types of second crossover sections 24 and 25: one with a pitch of 5 and the other with a pitch of 7. For example, in the U1 coil section 31 of FIG. 4, a second crossover section 24 with a pitch of 7 is provided between slots 11 #42 and #1, and third crossover sections 25 with a pitch of 5 are provided between slots #43 and #48 and between slots #7 and #12. In contrast, in the U2 coil section 32 of FIG. 5, a second crossover section 24 with a pitch of 5 is provided between slots 11 #43 and #48, and third crossover sections 25 with a pitch of 7 are provided between slots #42 and #1 and between slots #6 and #13.

[0045] 9A and 9B, the second crossover sections 24 or the third crossover sections 25 connected to the slot insertion sections 21 arranged in the same slot 11 and having different pitch numbers are arranged so as to overlap each other when viewed from the axial direction (Z direction). The second crossover section 24 or the third crossover section 25 having a larger pitch number is arranged above (in the Z1 direction) the second crossover section 24 or the third crossover section 25 having a smaller pitch number. Specifically, the second crossover section 24 and the third crossover section 25 having a pitch number of 7 are arranged so as to cover the second crossover sections 24 and 25 having a pitch number of 5 from above, respectively.

[0046] 4 to 7, the slot insertion portions 21 that form one round of the plurality of wave winding portions 20a to 20d and the slot insertion portions 21 that form the other round of the plurality of wave winding portions 20a to 20d are respectively arranged in adjacent slots 11. Furthermore, the U-phase coil 30, the V-phase coil 40, and the W-phase coil 50 are each arranged alternately in a pair of adjacent slots 11 along the radial direction.

[0047] For example, in the U-phase U1 coil portion 31 of Fig. 4, the slot insertion portions 21 forming the wave winding portions 20a to 20d are housed in two circumferentially adjacent slots 11, namely, #1 and #48, #6 and #7, #12 and #13, #18 and #19, #24 and #25, #30 and #31, #36 and #37, and #42 and #43. In adjacent (one full reciprocation) wave winding portions 20a to 20d, the slot insertion portions 21 are alternately arranged in different slots 11. The U-phase U2 coil portion 32, U3 coil portion 33, and U4 coil portion 34 of Figs. 5 to 7 are similar to the U-phase U1 coil portion 31. This makes it possible to prevent deviation in the positional relationship between the U1 coil portion 31, U2 coil portion 32, U3 coil portion 33, and U4 coil portion 34 of the U phase and the permanent magnet (not shown) of the rotor 150.

[0048] In this embodiment, the stator coil 20 is formed using seven types of coil pieces 70. That is, three types of coil pieces 70 are used to form a pair of slot insertion portions 21 and a first crossover portion 23, two types of coil pieces 70 are used to form a pair of slot insertion portions 21 and a second crossover portion 24, and two types of coil pieces 70 are used to form a pair of slot insertion portions 21 and a third crossover portion 25. The three types of coil pieces 70 that form a pair of slot insertion portions 21 and a first crossover portion 23 are three types of coil pieces 70 that connect the second turn to the third turn, the fourth turn to the fifth turn, and the sixth turn to the seventh turn on the Z1 direction side of the first crossover portion 23. The two types of coil pieces 70 that form a pair of slot insertion portions 21 and a second crossover portion 24 and the two types of coil pieces 70 that form a pair of slot insertion portions 21 and a third crossover portion 25 each have two types of pitch numbers: five and seven.

[0049] Here, the effect of this embodiment will be described with reference to a comparative example shown in FIG.

[0050] 10 is a perspective view of a stator 100′ according to a comparative example. The stator 100′ according to the comparative example differs in that some of the power line terminals 61′ and neutral line terminals 62′ are arranged radially inward of the stator core 10.

[0051] In such a comparative example, as described above in the section "Problems to be Solved by the Invention," Wiring from the innermost power line terminal 61' (see, for example, cable 610' in FIG. 10) needs to be routed radially outward from the axially outer side of the coil end (needs to straddle the coil end in the radial direction), which tends to increase the axial size of the stator 100' due to the stator coil 20'. In particular, when the number of parallel coil portions of each phase is four or more, as in this embodiment, such an arrangement of radially inner terminals is likely to be adopted due to the large number of terminals.

[0052] In contrast, according to this embodiment, as described above, all of the power line terminals 61 and neutral line terminals 62 for each phase are disposed radially outside the stator core 10. This configuration can avoid the inconvenience that occurs when at least one power line terminal 61 is disposed radially inside. That is, unlike the comparative example described above with reference to FIG. 10, it is possible to prevent an increase in the axial size of the stator 100 due to the stator coil 20. In other words, according to this embodiment, it is possible to reduce the axial size of the stator 100 while keeping the number of parallel coil portions for each phase at four.

[0053] 3A, the power line terminals 61 can be disposed axially more inward than the outermost axial position of the transition portion 22 (i.e., the outermost axial position of the coil end, see line L3) as viewed in the radial direction. This prevents the power line terminals 61 from increasing the axial size of the stator 100, and as a result, it becomes possible to reduce the axial size of the stator 100. In this case, the wiring connected to the power line terminals 61 and connected to the inverter (not shown) (for example, a cable-type wiring) can also be disposed axially more inward than the outermost axial position of the transition portion 22 as viewed in the radial direction.

[0054] 3A (and 3), the neutral terminal 62 and the neutral bus bar 63 connecting it can be disposed axially more inward than the outermost axial position of the transition portion 22 (i.e., the outermost axial position of the coil end, see line L3) as viewed in the radial direction. This prevents an increase in the axial size of the stator 100 due to the neutral terminal 62 and the neutral bus bar 63 connecting it, and as a result, it is possible to reduce the axial size of the stator 100.

[0055] In this embodiment, in addition to the above-mentioned effects, the following effects can be obtained.

[0056] In this embodiment, as described above, the first crossover portions 23 connect pairs of slot insertion portions 21 together so that the radial positions of the connected slot insertion portions 21 change stepwise toward one radial side, thereby forming wave winding portions 20a to 20d that are wave-wound around the stator core 10 together with the slot insertion portions 21. This allows the slot insertion portions 21 to be connected together without providing a portion where the radial positions of the connected slot insertion portions 21 change midway, unlike when radially adjacent slot insertion portions 21 are alternately connected in each of the multiple slots 11. This prevents an increase in the variety of shapes of the coil pieces 70 on one axial side of the stator core 10. As a result, it is possible to prevent an increase in the variety of coil pieces 70 used to form the stator coil 20. Furthermore, in this embodiment, as described above, the second crossover portion 24 and the third crossover portion 25 connect pairs of the slot insertion portions 21 together, thereby connecting one end of the wave winding portions 20a to 20d of one round trip formed by the first crossover portion 23 and the slot insertion portion 21 in a folded-back manner. This allows the wave winding portions 20a to 20d to be connected in a folded-back manner by the second crossover portion 24 and the third crossover portion 25, which connect the slot insertion portions 21 that are at the same radial position within the slot 11, and therefore prevents the shape of the folded-back portion from becoming complex.

[0057] In this embodiment, as described above, the radial positions of the connected slot insertion portions 21 between one and the other of the wave winding portions 20a to 20d for one round trip are arranged so as to change stepwise in parallel with each other, so that the shapes of the conductors (coil pieces 70) constituting each of the one and the other of the wave winding portions 20a to 20d for one round trip can be made common. Therefore, even when the wave winding portions 20a to 20d for one round trip are connected in a folded-back manner, the number of types of coil pieces 70 for forming the stator coil 20 can be reduced.

[0058] In this embodiment, as described above, the wave winding portions 20a to 20d can be formed so that the slot insertion portions 21 that are connected in stages from one radial end to the other radial end are arranged in each of the multiple slots 11, so that the ends of the wave winding portions 20a to 20d can be arranged at the outermost radial positions. Therefore, when connecting the power line terminal 61 or the neutral conductor terminal 62 to the stator coil 20, the manufacturing process can be made less complicated than when connecting to the conductor (coil piece 70) midway through the slot 11.

[0059] In this embodiment, as described above, the stator coil 20 is formed by folding back multiple times and wave-wound using the plurality of wave winding portions 20a to 20d, the second crossover portion 24 (outermost coil end portion), and the third crossover portion 25 (innermost coil end portion), so that the stator coil 20 can be formed so as to be wave-wound while folding back multiple times at each of the innermost and outermost radial portions of the slot 11. Therefore, even when the number of slot insertion portions 21 housed in one slot 11 is large, the stator coil 20 can be formed by folding back multiple times at each of the innermost and outermost radial portions of the slot 11, so that the number of types of coil pieces 70 constituting the stator coil 20 can be prevented from increasing.

[0060] In this embodiment, as described above, the stator coil 20 can be formed by connecting pairs of slot insertion portions 21 that are arranged so as to be shifted from each other radially outward or inward, so that the slot insertion portions 21 can be densely arranged in each of the multiple slots 11. Therefore, while efficiently connecting to the multiple slot insertion portions 21 arranged in the slots 11, the slot insertion portions 21 can be connected in pairs so that the radial positions of the connected slot insertion portions 21 are changed stepwise in order toward one radial side.

[0061] Here, if the slot insertion portions 21 are arranged in the same slots 11 in both one and the other of the wave winding portions 20a to 20d for one round trip, the positional relationship of the stator coil 20 with respect to the magnets arranged in the rotor 150 that faces the stator 100 will be biased, causing bias in the current flowing through the wave winding portions 20a to 20d. In consideration of this point, in this embodiment, as described above, the slot insertion portions 21 that form one of the wave winding portions 20a to 20d for one round trip and the slot insertion portions 21 that form the other of the wave winding portions 20a to 20d for one round trip are arranged in adjacent slots 11, thereby preventing bias in the current flowing through the wave winding portions 20a to 20d.

[0062] 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.

[0063] For example, in the above-described embodiment, the neutral terminals 62 are also all disposed radially outward, but some or all of the neutral terminals 62 may be disposed radially inward of the stator core 10. In other words, some or all of the second slot insertion portion 21B may be disposed on the radially innermost side within the slot 11.

[0064] In the above-described embodiment, the first crossover portion 23 forming one of the wave winding portions 20a to 20d and the first crossover portion 23 forming the other of the wave winding portions 20a to 20d have their radial positions of the connecting slot insertion portions 21 changed in stages in parallel to each other, but this is not limiting. For example, the radial positions of the slot insertion portions of one of the wave winding portions and the other of the wave winding portions in one of the wave winding portions may not be parallel to each other.

[0065] In the above-described embodiment, the wave winding portions 20a to 20d are folded back at the outermost and innermost radial positions, but the present invention is not limited to this. For example, the wave winding portions may be folded back midway in the radial direction.

[0066] In the above-described embodiment, the stator coil 20 is formed by folding back three times using four wave winding portions 20a to 20d, but this is not limiting. For example, the stator coil 20 may be formed by folding back only once using two wave winding portions.

[0067] In the above-described embodiment, the first crossover portion 23 connects pairs of slot insertion portions 21 that are arranged in different slots 11 and that are offset from each other by one radial direction, either outward or inward, but this is not limiting. For example, the first crossover portion 23 may connect slot insertion portions that are offset by two or more slot insertion portions. In other words, the first crossover portion 23 may connect slot insertion portions that are offset from each other by two or more turns.

[0068] In the above-described embodiment, the slot insertion portion 21 forming one of the wave winding portions 20a to 20d and the slot insertion portion 21 forming the other of the wave winding portions 20a to 20d are respectively arranged in adjacent slots 11, but this is not limited to this. For example, the slot insertion portion forming one of the wave winding portions for one round trip and the slot insertion portion forming the other of the wave winding portions for one round trip may be arranged in a common slot. Furthermore, the slot insertion portion forming one of the wave winding portions for one round trip and the slot insertion portion forming the other of the wave winding portions for one round trip may be arranged in slots spaced apart from each other.

[0069] In the above-described embodiment, the stator coil 20 is formed by the inverted U-shaped coil pieces 70, but this is not limiting. For example, after placing rod-shaped coil pieces in the slots as slot insertion portions, coil end portions may be formed by joining coil pieces separate from the rod-shaped coil pieces. Also, a coil portion may be formed by combining inverted U-shaped coil pieces and U-shaped coil pieces from one axial side and the other axial side of the stator core.

[0070] In the above-described embodiment, the U-phase coil 30, the V-phase coil 40, and the W-phase coil 50 each constitute a four-parallel coil configuration, but this is not limiting. For example, each of the U-phase coil, the V-phase coil, and the W-phase coil may be configured with more than six parallel coils, such as six or eight parallel coils.

[0071] In the above-described embodiment, the stator core 10 is provided with 48 slots 11, and each slot 11 houses eight slot insertion portions 21 aligned radially, but this is not limiting. For example, the number of slots in the stator core may be other than 48. Furthermore, the number of slot insertion portions housed in one slot may also be other than eight. [Explanation of symbols]

[0072] 100 Stator (stator for rotating electrical machine), 20 Stator coil, 31 U1 coil section (coil section), 32 U2 coil section (coil section), 33 U3 coil section (coil section), 34 U4 coil section (coil section), 41 V1 coil section (coil section), 42 V2 coil section (coil section), 43 V3 coil section (coil section), 44 V4 coil section (coil section), 51 W1 coil section (coil section), 52 W2 coil section (coil section), 53 W3 coil section (coil section), 54 W4 coil section (coil section), 10 stator core, 11 slot, 21 slot insertion section, 21A first slot insertion section, 21B second slot insertion section, 21C third slot insertion section, 22 crossover section, 61 power line terminal, 62 neutral line terminal

Claims

1. a stator coil in which four or more sets of coil portions for each phase are connected in parallel circuits between a neutral terminal and a power line terminal for each phase; a stator core having a plurality of slots and around which the stator coil is wound, The stator coil is a slot insertion portion to be inserted into each corresponding slot among the plurality of slots; a bridge portion that is exposed from an axial end face of the stator core and extends in a circumferential direction so as to connect the pair of slot insertion portions, In each phase, among the plurality of slot insertion portions in each set, a first slot insertion portion directly connected to the power line terminal is located on the outermost diameter side of the corresponding slot on one axial side of the stator core, The power line terminal is located axially inward of an axially outermost position of the crossover portion when viewed in a radial direction.

2. 2. The stator for a rotating electric machine according to claim 1, wherein, in each phase, among the plurality of slot insertion portions in each set, a second slot insertion portion directly connected to the neutral wire terminal is located on the outermost diameter side of the corresponding slot on one axial side of the stator core.

3. 3. The stator for a rotating electric machine according to claim 2, wherein, when the plurality of slots are assigned slot numbers that increase relatively in sequence in a clockwise or counterclockwise direction around the stator core as viewed in the axial direction, in each set relating to one phase in the stator coil, each slot insertion portion along the current flow direction from the first slot insertion portion to the second slot insertion portion is inserted into the corresponding slot in such a manner that a reversal occurs at least once, in which the slot number changes from a first direction, either an increasing direction or a decreasing direction, to a second direction, the other direction.

4. In each phase, the plurality of slot insertion portions in each set include, in addition to the first slot insertion portion and the second slot insertion portion, at least one third slot insertion portion located on an innermost diameter side of the corresponding slot, 4. The stator for a rotating electric machine according to claim 3, wherein in each set, each slot insertion portion along the flow direction from the first slot insertion portion to the second slot insertion portion is inserted into a corresponding slot in a manner such that the slot number changes in the first direction from the first slot insertion portion to the first third slot insertion portion in the flow direction, and the slot number changes in the second direction from the last third slot insertion portion in the flow direction to the second slot insertion portion.

5. 4. The stator for a rotating electric machine according to claim 3, wherein in each set, each slot insertion portion along the flow direction from the first slot insertion portion to the second slot insertion portion is inserted into the corresponding slot in such a manner that when the slot number changes in the first direction, the radial position within the slot is shifted radially inward by one turn, and when the slot number changes in the second direction, the radial position within the slot is shifted radially outward by one turn or the same radial position is maintained.

6. The stator coil further includes a neutral bus bar that connects the plurality of neutral terminals of the stator coil, The stator for a rotating electric machine according to claim 1 , wherein the neutral bus bar is located axially inward of an outermost position in the axial direction of the transition portion when viewed in the radial direction.

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