Stator for rotating electrical machine

Abstract

To reduce circulating current in a configuration where a stator coil includes, for each phase, two sets of coils connected in parallel and is wound with a short-pitch winding.SOLUTION: Disclosed is a stator for a rotary electric machine which includes: a stator core having a plurality of slots; and a stator coil formed such that, for each phase, a plurality of coil pieces is assembled over the entire circumference of the stator core. The stator coil includes, for each phase, two sets of coils connected in parallel and is wound with a short-pitch winding. For each phase, the coil center of a coil of a first set in a circumferential direction and the coil center of a coil of a second set in a circumferential direction each match each coil center position that is the coil center position for each phase and that is formed for each magnetic pole pitch over the entire circumference of the stator core, or are alternately shifted by the same amount along the circumferential direction on one side and the other side with respect to the coil center position for each magnetic pole pitch.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] A technique is known in which stator coils are wound in short pitch using a plurality of layers (radial layers within slots) for each phase.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a configuration where stator coils are connected in parallel in two sets for each phase and wound in short pitch, a circulating current that circulates within the loop of the coils connected in parallel for each phase is likely to occur.

[0005] Therefore, on one aspect, the present disclosure aims to reduce the circulating current in a configuration where stator coils are connected in parallel in two sets for each phase and wound in short pitch.

Means for Solving the Problems

[0006] On one aspect, it includes a stator core having a plurality of slots, and a stator coil formed by assembling a plurality of coil segments around the entire circumference of the stator core for each phase, wherein the stator coil is wound in short pitch with two sets connected in parallel for each phase, for each phase, the circumferential coil center of the first set of coils and the circumferential coil center of the second set of coils are respectively, The coil center position for each phase, which coincides with each coil center position formed for each pole pitch over the entire circumference of the stator core, or A stator for a rotating electrical machine is provided, in which the coil center positions for each pole pitch are alternately shifted by the same amount along the circumferential direction to one side and the other side with respect to the coil center positions for each pole pitch.

Advantages of the Invention

[0007] On one aspect, according to the present disclosure, in a configuration where stator coils are connected in two parallel sets for each phase and wound in short-pitch winding, it becomes possible to reduce circulating current.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Modes for Carrying Out the Invention

[0009] Hereinafter, each example will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not limited thereto, and the shapes in the drawings may be exaggerated partially for the convenience of explanation.

[0010] [Example 1] FIG. 1 is a diagram showing an outline of a stator 10 for a rotating electrical machine of this example. The stator 10 for a rotating electrical machine has a stator core 112 and a stator coil 114. The stator core 112 has a cylindrical form having a central axis I and may be formed of, for example, laminated steel plates. The configuration of the stator coil 114 will be described in detail below.

[0011] FIG. 2 is a diagram showing an example of a connection mode of the stator coil 114 related to the stator 10 for a rotating electrical machine of this example. In this example, as an example, it has a three-phase eight-pole configuration and the number of slots is 48 (= 3 × 8 × 2), but it is also applicable to configurations with other numbers of poles.

[0012] As schematically shown in FIG. 2, the stator coil 114 is electrically connected at the neutral point of the Y connection in two sets for each phase in a parallel relationship. Specifically, the stator coil 114 has two sets (pairs), namely the first coil of the U phase (hereinafter also referred to as the "U1-phase coil 221(U1)") and the second coil of the U phase (hereinafter also referred to as the "U2-phase coil 221(U2)"), which are electrically connected in a parallel relationship between the neutral point and the U-phase terminal 90U on the power line side. Hereinafter, when distinction is required, the U phase related to the U1-phase coil 221(U1) is also referred to as the U1 phase, and the U phase related to the U2-phase coil 221(U2) is also referred to as the U2 phase.

[0013] The same applies to the other phases. For the stator coil 114, two sets (pairs), namely the first coil 221V1 of the V phase and the second coil 221V2 of the V phase, are electrically connected in a parallel relationship between the neutral point and the V-phase terminal 90V on the power line side. Also, for the stator coil 114, two sets (pairs), namely the first coil 221W1 of the W phase and the second coil 221W2 of the W phase, are electrically connected in a parallel relationship between the neutral point and the W-phase terminal 90W on the power line side. Note that the U-phase terminal 90U, the V-phase terminal 90V, and the W-phase terminal 90W are electrically connected to an inverter or a power source (not shown) via a terminal block 59 (see FIG. 1).

[0014] The U1-phase coil 221(U1) includes eight coils U1-1 to U1-8 connected in series, and the same applies to the U2-phase coil 221(U2), which includes eight coils U2-1 to U2-8 connected in series. The same also applies to the other phases (V phase and W phase).

[0015] Next, with reference to FIGS. 3 to 6, the details of the configuration of the stator coil 114 of this embodiment will be described. Hereinafter, mainly the configuration of the U phase will be described, but the same may apply to the other V phase and W phase.

[0016] FIG. 3 is an overall winding diagram of the stator coil 114 of this embodiment. Together with a schematic diagram of the stator coil 114 viewed axially and developed in the circumferential direction, the U1-phase coil 221 (U1) and the U2-phase coil 221 (U2) are shown separately. Also, in FIG. 3, for ease of viewing, only a part of 48 slots is divided into two stages. In FIG. 3, the numbers attached to each slot 23 represent the slot numbers, and the numbers 1 to 6 attached to the left side of the stator core 112 represent the number of turns. Also, in FIG. 3, for the crossover portion of the stator coil 114 (see the crossover portion 54 in FIG. 4), the lead side is indicated by a dashed line, and the semi-lead side is indicated by a solid line. This rule is common to the following similar figures (such as FIG. 8 to be described later).

[0017] FIG. 4 is an explanatory diagram of the coil segment 52. FIG. 5 is a winding diagram of a general portion (a part of FIG. 3) where the neutral point and the like are not related, and is an explanatory diagram of a repeating pattern. FIG. 6 is a side view (a side view viewed radially from the radially inner side) showing a method of arranging the coil segments forming the general portion of the stator coil 114. In FIG. 6, the current flowing through the stator coil 114 at a certain point in time is schematically shown by an arrow R5. Also, in FIG. 6, the welding portions 60 between the coil segments are schematically shown together with the number of coil segments and the symbol (diagonal lines) indicating the number. FIG. 7 is a diagram showing the positional relationship (axial positional relationship) between the coil segments at the coil end portion, and is a schematic diagram of a part of the stator coil 114 (a part in the circumferential direction and a part in the axial direction) viewed from the inner diameter side. In FIG. 7, the star marks and numbers indicate the slot pitch.

[0018] In the following description, the coil segment is a coil segment forming the stator coil 114, and may be, for example, a coil segment in a form called a segment coil. In this embodiment, as an example, the coil segment may be a U-shaped coil segment 52 as shown in FIG. 4. Also, in the following description, the slot pitch for N (N is a positive integer) slots is also referred to as the N-slot pitch. For example, the slot pitch for 6 slots is also referred to as the 6-slot pitch. Note that N - 1 slots are located between the two slots in the circumferential direction that form the N-slot pitch.

[0019] In the example shown in FIG. 4, one coil piece 52 may be formed in a substantially U shape having a pair of linear slot accommodating portions 50 and a connecting portion 54 connecting the pair of slot accommodating portions 50. The connecting portion 54 on the other axial side (the upper side in FIG. 4) may be formed by forming it in the circumferential direction from the state shown in FIG. 4. At the end of the connecting portion 54 on the other axial side (the upper side in FIG. 4), a connecting portion 40 that is connected to the connecting portion 40 of the connecting portion 54 of the other coil piece 52 is set. Note that the connecting portion 40 is a portion where the insulating film 130 is removed (that is, a portion where the conductor portion related to the linear conductor is exposed).

[0020] When assembling the coil piece 52 to the stator core 112, the pair of slot accommodating portions 50 are respectively inserted (wound) into the slots 23 between the teeth 22 in the circumferential direction (see FIG. 3). In this case, the coil piece 52 can be assembled, for example, in the axial direction.

[0021] Into one slot, the slot accommodating portions 50 of the coil piece 52 shown in FIG. 3 are inserted side by side in the radial direction in a number corresponding to the number of turns (in this embodiment, six as an example). Therefore, a plurality of connecting portions 54 extending in the circumferential direction are arranged side by side in the radial direction at both axial ends of the stator core 112. Note that the connecting portion 54 (and the connecting portion 40 which is a part thereof) forms a coil end portion which is a portion protruding axially outward from the axial end surface of the stator core 112.

[0022] Note that the lower connecting portion 54 of the coil piece 52 may have an offset portion 521B that offsets in a direction of being separated from each other by only one layer in the radial direction. The upper connecting portion 54 may also have a similar offset portion (not shown).

[0023] In this embodiment, both the U1-phase coil 221 (U1) and the U2-phase coil 221 (U2) are formed from a plurality of coil pieces. The forms of the plurality of coil pieces are of multiple types, and the types differ according to the circumferential interval (slot pitch) of the pair of slots 23 into which they are inserted. The plurality of types of coil pieces do not necessarily all have to be in the form of a U-shape; they may include coil pieces in the form of an I-shape (i.e., coil pieces having only one slot accommodating portion 50), or they may all be in the form of an I-shape. In the following description, the coil piece 52 inserted into one slot 23 means the coil piece 52 having the slot accommodating portion 50 inserted into the one slot 23. Therefore, the U-shaped coil piece 52 having two slot accommodating portions 50 can also be regarded as a combination of a coil piece inserted into one slot 23 and a coil piece inserted into another one slot 23.

[0024] In this embodiment, the stator coil 114 is wound in a short-pitch winding. Specifically, the U1-phase coil 221 (U1) has coil pieces (hereinafter, also referred to as "first coil pieces p6" for the sake of distinction) inserted into a plurality of slots 23 (hereinafter, also referred to as "central slots 23c") that form 6 slot pitches (corresponding to the pole pitch) over the entire circumference of the stator core 112. Each first coil piece p6 has the slot accommodating portions 50 on both circumferential sides inserted into the pair of central slots 23c that form 6 slot pitches. Note that "a coil piece is inserted into a slot 23" means that the slot accommodating portion 50 of the coil piece is inserted into the slot 23.

[0025] Also, the U1-phase coil 221 (U1) has coil pieces (hereinafter, referred to as "second coil pieces p4" for the sake of distinction) inserted into a plurality of pairs of slots 23 that form 4 slot pitches. Each second coil piece p4 has the slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 that form 4 slot pitches.

[0026] Further, the U1-phase coil 221 (U1) has coil pieces (hereinafter referred to as "third coil pieces p5" for distinction) inserted into a plurality of pairs of slots 23 that form a 5-slot pitch. Each third coil piece p5 has slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 that form a 5-slot pitch.

[0027] Also, the U1-phase coil 221 (U1) has coil pieces (hereinafter referred to as "fourth coil pieces p7" for distinction) inserted into a plurality of pairs of slots 23 that form a 7-slot pitch. Each fourth coil piece p7 has slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 that form a 7-slot pitch.

[0028] In this embodiment, when each triple slot composed of three slots 23 adjacent in the circumferential direction with the central slot 23c as the center is alternately the first triple slot 301 and the second triple slot 302 in the circumferential direction, the first coil piece p6 to the fourth coil piece p7 are arranged in the following relationship as shown in FIGS. 5 and 6.

[0029] In the U1 phase (U1-phase coil 221 (U1)), the first coil piece p6, the third coil piece p5, and the fourth coil piece p7 are inserted into the central slot 23c of the first triple slot 301 (hereinafter also referred to as "first central slot 301c" when distinguishing). In this case, for the first coil piece p6, the third coil piece p5, and the fourth coil piece p7, the slot accommodating portions 50 on one circumferential side of each are inserted into the first central slot 301c.

[0030] Also, in the U1 phase, only the first coil piece p6 is inserted into the central slot 23c of the second triple slot 302 (hereinafter also referred to as "second central slot 302c" when distinguishing).

[0031] In the U1 phase, the second coil piece p4 is provided in a manner paired with the first coil piece p6. Therefore, the second coil pieces p4 adjacent in the circumferential direction are inserted into the respective slots 23 on both sides of the center slot 23c. At this time, the second coil piece p4 and the first coil piece p6 are arranged concentrically with the coil center position CT0 as the center.

[0032] In the U1 phase, the third coil piece p5 and the fourth coil piece p7 are arranged only one by one every 12 slot pitches, different from the first coil piece p6 and the second coil piece p4. That is, between the pair of first center slots 301c (or between the pair of second center slots 302c) adjacent in the circumferential direction, two first coil pieces p6 and two second coil pieces p4 are provided respectively, while only one third coil piece p5 and one fourth coil piece p7 are provided. Also, the third coil piece p5 and the fourth coil piece p7 are arranged on the same one side of both sides in the circumferential direction of the first center slot 301c.

[0033] In this case, in the U1 phase, six slot accommodating portions 50 in total are inserted into the first triple slot 301, with four in the first center slot 301c and one in each of the slots 23 on both sides in the circumferential direction of the first center slot 301c. Also, six slot accommodating portions 50 in total are inserted into the second triple slot 302, with two in the second center slot 302c and two in each of the slots 23 on both sides in the circumferential direction of the second center slot 302c.

[0034] The U2 phase coil 221 (U2) has coil pieces (first coil pieces p6) inserted into a plurality of slots 23 (center slots 23c) forming a 6-slot pitch over the entire circumference of the stator core 112, similar to the above-described U1 phase coil 221 (U1). The center slot 23c is common with the center slot 23c related to the U1 phase coil 221 (U1). Each first coil piece p6 has the slot accommodating portions on both sides in the circumferential direction inserted into the pair of center slots 23c forming a 6-slot pitch.

[0035] Further, the U2-phase coil 221 (U2) has coil pieces (second coil pieces p4) inserted into a plurality of pairs of slots 23 forming a 4-slot pitch. Each second coil piece p4 has slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 forming a 4-slot pitch.

[0036] Further, the U2-phase coil 221 (U2) has coil pieces (third coil pieces p5) inserted into a plurality of pairs of slots 23 forming a 5-slot pitch. Each third coil piece p5 has slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 forming a 5-slot pitch.

[0037] Further, the U2-phase coil 221 (U2) has coil pieces (fourth coil pieces p7) inserted into a plurality of pairs of slots 23 forming a 7-slot pitch. Each fourth coil piece p7 has slot accommodating portions 50 on both circumferential sides inserted into each pair of slots 23 forming a 7-slot pitch.

[0038] Thus, the configuration of the U2-phase coil pieces is substantially the same as that of the U1-phase coil pieces, but the detailed shapes may be different. For example, the shape of the first coil piece p6 of the U2-phase may be slightly different from that of the second coil piece p4 of the U1-phase.

[0039] In the U2-phase (U2-phase coil 221 (U2)), with respect to the above-described U1-phase (U1-phase coil 221 (U1)), the configuration (arrangement and direction of current) of each coil piece in the first triple slot 301 and the configuration (arrangement and direction of current) of each coil piece in the second triple slot 302 are in a substantially inverted relationship.

[0040] Specifically, in the U2-phase, only the first coil piece p6 is inserted into the first central slot 301c.

[0041] Also, in the U2 phase, the first coil piece p6, the third coil piece p5, and the fourth coil piece p7 are inserted into the second central slot 302c. In this case, for the first coil piece p6, the third coil piece p5, and the fourth coil piece p7, the slot accommodating portions 50 on the other side in the circumferential direction are inserted into the second central slot 302c.

[0042] Also, in the U2 phase, the second coil piece p4 is provided in a manner paired with the first coil piece p6. Therefore, the second coil pieces p4 adjacent in the circumferential direction are inserted into the respective slots 23 on both sides of the central slot 23c. At this time, the second coil piece p4 and the first coil piece p6 are arranged concentrically with the coil center position CT0 as the center.

[0043] Also, in the U2 phase, the third coil piece p5 and the fourth coil piece p7 are arranged only one by one every 12 slot pitches, different from the first coil piece p6 and the second coil piece p4. That is, between the pair of first central slots 301c adjacent in the circumferential direction (or between the pair of second central slots 302c), two first coil pieces p6 and two second coil pieces p4 are provided respectively, while only one third coil piece p5 and one fourth coil piece p7 are provided. Also, the third coil piece p5 and the fourth coil piece p7 are arranged on the same one side of both sides in the circumferential direction of the first central slot 301c. This point is the same as that of the U1 phase coil 221 (U1).

[0044] In this case, in the U2 phase, in the first triple slot 301, six slot accommodating portions 50 are inserted in total: two in the first central slot 301c and two in each of the slots 23 on both circumferential sides of the first central slot 301c. In the second triple slot 302, six slot accommodating portions 50 are inserted in total: four in the second central slot 302c and one in each of the slots 23 on both circumferential sides of the second central slot 302c. As described above, in the U1 phase and the U2 phase, the arrangement (and the direction of current) of the slot accommodating portions 50 of each coil piece in the first triple slot 301 and the arrangement (and the direction of current) of the slot accommodating portions 50 of each coil piece in the second triple slot 302 are in an inverted relationship. That is, when one is shifted by six slots and also inverted in the radial direction, it overlaps with the other.

[0045] In this embodiment, the stator coil 114 is joined together at one axial side of each coil piece. Also, each pair of slots 23 into which each pair of coil pieces joined in each phase are inserted are separated in the circumferential direction by a certain number of slots. In this embodiment, each pair of slots 23 into which each pair of coil pieces joined in each phase are inserted are all separated by five slots as shown in FIGS. 3 and 6 (see the welding portion 60), etc. Thereby, since the welding positions can be set at a constant pitch on the welding side (lead side), the efficiency of the welding process can be easily improved.

[0046] Also, in this embodiment, as schematically shown in FIG. 7, the coil end portion (the portion axially outside the axial end surface of the stator core 112) by the first coil piece p6 extends axially outside more than the coil end portion by the second coil piece. This is the same for both the U1 phase coil 221 (U1) and the U2 phase coil 221 (U2). Thereby, the size of the coil end portion in the entire stator coil 114 can be reduced.

[0047] Next, referring to FIGS. 8 to 13, a further effect of this embodiment will be described.

[0048] FIG. 8 is an explanatory diagram of the stator coil 114' according to the comparative example. The upper part shows the configuration of the U1-phase coil 221(U1)', and the lower part shows the configuration of the U2-phase coil 221(U2)'. FIG. 8 shows the configuration of the general part of the comparative example corresponding to FIG. 5. FIG. 9 is an explanatory diagram of the circulating current, and FIG. 10 is an explanatory diagram of the current waveform based on the analysis result of the comparative example. In FIG. 10, the rotor rotation angle (electrical angle) is taken on the horizontal axis, and the current waveforms of each phase for 360 degrees are shown. FIG. 11 is an explanatory diagram of the torque waveform (each torque waveform at specific operating points A and B) based on the analysis result of the comparative example. In FIG. 12, the rotor rotation angle (electrical angle) is taken on the horizontal axis, and the torque waveforms for 360 degrees are shown. FIG. 12 is an explanatory diagram of the current waveform based on the analysis result of this embodiment, and is compared with FIG. 10. FIG. 13 is an explanatory diagram of the torque waveform (each torque waveform at specific operating points A and B) based on the analysis result of this embodiment, and is compared with FIG. 11.

[0049] In the comparative example, the stator coil 114' is wound in a short-pitch winding, and the arrangement of the slot accommodating portions 50 of each coil piece in the first triple slot 301 (arrangement for 6 turns) and the arrangement of the slot accommodating portions 50 of each coil piece in the second triple slot 302 (arrangement for 6 turns) themselves are the same as those in this embodiment.

[0050] In the comparative example, the U1-phase coil 221(U1)' and the U2-phase coil 221(U2)' are wound in a relationship shifted by one slot with respect to each other. In this case, the circumferential coil center CT1' of the U1-phase coil 221(U1)' related to each pole and the circumferential coil center CT2' of the U2-phase coil 221(U2)' related to each pole are each shifted by a certain amount with respect to the circumferential coil center position CT0 for each pole pitch. Specifically, as shown in FIG. 8, the circumferential coil center CT1' of the U1-phase coil 221(U1)' is shifted to one side in the circumferential direction with respect to the coil center position CT0 (see arrow R81). This is the same shifting manner for any coil center position CT0 in the U1 phase. Also, the circumferential coil center CT2' of the U2-phase coil 221(U2)' is shifted to the other side in the circumferential direction with respect to the coil center position CT0 (see arrow R82). This is the same shifting manner for any coil center position CT0 in the U2 phase. Note that the coil center position CT0 corresponds to the intermediate position between adjacent center slots 23c in the circumferential direction and exists for each pair of adjacent center slots 23c in the circumferential direction. Therefore, the coil center positions CT0 exist in the same number as the number of poles, together with the circumferential coil center CT1' of the U1-phase coil 221(U1)'.

[0051] In such a comparative example, when each coil center CT1' of the U1 phase is shifted to one side in the circumferential direction with respect to each coil center position CT0, and each coil center CT2' of the U2 phase is shifted to the other side in the circumferential direction with respect to each coil center position CT0, a circulating current is likely to occur in the loop of the U1-phase coil 221(U1)' and the U2-phase coil 221(U2)' connected in parallel. Specifically, as schematically shown in FIG. 10, a significant difference occurs between the current flowing through the U1-phase coil 221(U1)' connected in parallel (see current I1 in FIG. 10) and the current flowing through the U2-phase coil 221(U2)' (see current I2 in FIG. 10), and a circulating current is likely to occur due to this difference. When such a circulating current occurs, as shown in FIG. 10, a significant difference occurs in the current waveforms between the U1 phase and the U2 phase (in this case, it is a significantly distorted sine wave that does not overlap with each other), and as a result, as shown in FIG. 11, there arises a problem that the torque decreases with respect to the torque target value.

[0052] In contrast, according to this embodiment, as shown in FIG. 6, each coil center CT1 of the U1 phase (the coil center of each of the coils U1-1 to U1-8) coincides with each coil center position CT0, and each coil center CT2 of the U2 phase (the coil center of each of the coils U2-1 to U2-8) coincides with each coil center position CT0. As a result, the above-mentioned inconveniences occurring in the comparative example can be reduced or eliminated. Specifically, there is no significant difference in the current flowing through the U1-phase coil 221 (U1) and the U2-phase coil 221 (U2) connected in parallel, and it becomes difficult for a circulating current to occur. Therefore, as shown in FIG. 12, there is no significant difference in the current waveforms between the U1 phase and the U2 phase (in this case, it is a smooth sine wave with little distortion due to short-pitch winding, and the waveforms of the sine waves overlap each other), and as a result, as shown in FIG. 13, the torque can be generated as targeted without a decrease in the torque target value.

[0053] [Embodiment 2] Next, referring to FIG. 14, another embodiment (hereinafter, referred to as "Embodiment 2" for distinction) will be described.

[0054] FIG. 14 is a partial winding diagram of the stator coil 114A according to Embodiment 2, and the viewing method of the figure is the same as that of FIG. 3.

[0055] Also in this embodiment, the stator coil 114A is wound with short-pitch winding, and the arrangement of the slot accommodating portions 50 of each coil piece in the first triple slot 301 and the arrangement of the slot accommodating portions 50 of each coil piece in the second triple slot 302 themselves are the same as those in Embodiment 1 described above.

[0056] The U1-phase coil 221A (U1) includes a plurality of fifth coil pieces c5 inserted into a plurality of pairs of slots 23 that form a 7-slot pitch (a slot pitch that is 1 slot larger than the pole pitch).

[0057] Also, the U1-phase coil 221A (U1) includes a plurality of sixth coil pieces c6 inserted into a plurality of slots 23 forming a 5-slot pitch (a slot pitch that is 1 slot smaller than the pole pitch).

[0058] In this embodiment, when each triple slot composed of three slots 23 adjacent in the circumferential direction with the central slot 23c as the center is alternately the first triple slot 301 and the second triple slot 302 in the circumferential direction, the fifth coil piece c5 and the sixth coil piece c6 are arranged in the following relationship.

[0059] In the U1 phase (U1-phase coil 221A (U1)), the fifth coil piece c5 and the sixth coil piece c6 are inserted into the first central slot 23c of the first triple slot 301, and the fifth coil piece c5 and the sixth coil piece c6 are inserted into the slots on both sides of the second triple slot 302.

[0060] For the fifth coil piece, the slot accommodating portion 50 on one side in the circumferential direction is inserted into the central slot 23c related to the first triple slot 301, and the slot accommodating portion 50 on the other side in the circumferential direction is inserted into the slot on one side in the circumferential direction with respect to the central slot 23c in the second triple slot 302.

[0061] In this case, in the U1 phase, in the first triple slot 301, six slot accommodating portions 50 are inserted into the first central slot 301c. On the other hand, in the first triple slot 301, no slot accommodating portion 50 is inserted into the slots on both sides in the circumferential direction of the first central slot 301c. Also, in the second triple slot 302, a total of six slot accommodating portions 50, three in each slot on both sides in the circumferential direction of the second central slot 302c, are inserted. On the other hand, in the second triple slot 302, no slot accommodating portion 50 is inserted into the second central slot 302c.

[0062] The U2-phase coil 221A (U2) includes a plurality of fifth coil pieces c5 inserted into a plurality of pairs of slots 23 that form a 7-slot pitch, similar to the above-described U1-phase coil 221A (U1). Further, the U2-phase coil 221A (U2) includes a plurality of sixth coil pieces c6 inserted into a plurality of pairs of slots 23 that form a 5-slot pitch.

[0063] In the U2 phase (U2-phase coil 221A (U2)), with respect to the above-described U1 phase (U1-phase coil 221A (U1)), the configuration (arrangement and current direction) of each coil piece in the first triple slot 301 and the configuration (arrangement and current direction) of each coil piece in the second triple slot 302 are in a substantially inverted relationship.

[0064] Specifically, in the U2 phase (U2-phase coil 221A (U2)), the fifth coil piece c5 and the sixth coil piece c6 are inserted into the second center slot 302c of the second triple slot 302, and the fifth coil piece c5 and the sixth coil piece c6 are inserted into the slots 23 on both sides of the first triple slot 301.

[0065] In this case, in the U2 phase, in the first triple slot 301, a total of six slot accommodating portions 50, three each, are inserted into the slots on both sides of the first center slot 301c. On the other hand, in the first triple slot 301, no slot accommodating portion 50 is inserted into the first center slot 301c. Further, in the second triple slot 302, six slot accommodating portions 50 are inserted into the second center slot 302c. On the other hand, in the second triple slot 302, no slot accommodating portion 50 is inserted into the slots 23 on both circumferential sides of the second center slot 302c. As described above, in the U1 phase and the U2 phase, the arrangement (and current direction) of the slot accommodating portions 50 of each coil piece in the first triple slot 301 and the arrangement (and current direction) of the slot accommodating portions 50 of each coil piece in the second triple slot 302 are in an inverted relationship. That is, when one is shifted by six slots and also inverted in the radial direction, it overlaps with the other.

[0066] Also in this embodiment, similar to the above-described Embodiment 1, the stator coil 114A has each coil piece joined to each other on one axial side. Further, each pair of slots 23 into which each pair of coil pieces joined in each phase are inserted are separated in the circumferential direction by a certain number of slots. In this embodiment, each pair of slots 23 into which each pair of coil pieces joined in each phase are inserted are separated by 5 slots as shown in FIG. 14 and the like. Thereby, since the welding locations can be set at a constant pitch on the welding side (lead side), the efficiency of the welding process can be easily improved.

[0067] Further, in this embodiment, compared to the above-described Embodiment 1, for example, the types of coil pieces forming the general portion can be reduced. That is, in the above-described Embodiment 1, there are 4 types of coil pieces forming the general portion even only due to the difference in slot pitch (even if the slot pitch is the same, the detailed portions of the coil pieces may be different), whereas in this embodiment, only 2 types are required for the difference in slot pitch. In this way, according to this embodiment, the types of coil pieces for forming the stator coil 114A can be reduced, and the manufacturing efficiency can be increased.

[0068] FIG. 15 is a side view (side view viewed in the radial direction from the inner side in the radial direction) showing a method of arranging coil pieces forming the general portion of the stator coil 114A according to Embodiment 2, similar to FIG. 6 above. In FIG. 15, the current flowing through the stator coil 114A at a certain point in time is schematically shown by an arrow R5. Further, in FIG. 15, the welding portions 60 between the coil pieces are schematically shown. FIG. 15 is also an explanatory diagram of the effect of reducing the circulating current according to this embodiment, showing the relationship between the coil centers CT1, CT2 of the stator coil 114A and the above-described coil center position CT0 (coil center position CT0 for each pole pitch). In FIG. 15, a winding diagram of the general portion is shown in the same manner as in FIG. 14. In FIG. 15, with respect to the U1 phase, the coil centers CT1 of the coils U1-2 and U1-3 are typically shown, but the same applies to the other coils U1-1, U1-4 to U1-8. The same applies to the U2 phase.

[0069] According to this embodiment, each coil center CT1 of the U1 phase (the coil centers of coils U1-1 to U1-8 respectively) is alternately displaced by the same amount along the circumferential direction to one side and the other side with respect to each coil center position CT0. Specifically, as shown in FIG. 15, the coil center CT1 of coil U1-2 is displaced by a certain amount Δd (for example, half of one slot pitch) to one circumferential side (the side close to coil U1-3) with respect to the corresponding coil center position CT0. Also, the coil center CT1 of coil U1-3 is displaced by a certain amount Δd to the other circumferential side (the side close to coil U1-2) with respect to the corresponding coil center position CT0. In this case, the displacement amount is the same at a certain amount Δd, and the displacement directions are alternately opposite in the circumferential direction, so they cancel each other out and it becomes difficult for a circulating current to occur. Similarly for the U2 phase, the coil center CT2 of coil U2-2 is displaced by a certain amount Δd to one circumferential side (the side far from coil U2-3) with respect to the corresponding coil center position CT0. Also, the coil center CT2 of coil U2-3 is displaced by a certain amount Δd to the other circumferential side (the side far from coil U1-2) with respect to the corresponding coil center position CT0. In this case, the displacement amount is the same at a certain amount Δd, and the displacement directions are alternately opposite in the circumferential direction, so they cancel each other out and it becomes difficult for a circulating current to occur.

[0070] In this way, also according to this embodiment, similar to the effect of Embodiment 1 described above with reference to FIGS. 12 and 13, there is no significant difference in the current waveforms between the U1 phase and the U2 phase. As a result, there is no decrease with respect to the torque target value, and it becomes possible to generate torque as per the target value.

[0071] As described above in detail for each embodiment, it is not limited to a specific embodiment, and various deformations and changes are possible within the scope described in the claims. Also, it is possible to combine all or a plurality of the constituent elements of the above-described embodiments.

Explanation of Reference Numerals

[0072] 10 ··· Stator for rotating electrical machine, 112 ··· Stator core, 114, 114A ··· Stator coils, 23 ··· Slots, 23c ··· Central slot, 52 ··· Coil segments, p6 ··· First coil segment, p4 ··· Second coil segment, p5 ··· Third coil segment, p7 ··· Fourth coil segment, c5 ··· Fifth coil segment, c6 ··· Sixth coil segment, 301 ··· First triple slot, 302 ··· Second triple slot, CT0 ··· Coil center position, CT1 ··· Coil center (coil center in the circumferential direction of the first set of coils), CT2 ··· Coil center (coil center in the circumferential direction of the second set of coils)

Claims

1. A stator core having a plurality of slots, and A stator coil formed by assembling a plurality of coil segments around the stator core for each phase over the entire circumference, and The stator coil has two sets connected in parallel for each phase and is wound in a short-pitch winding, For each phase, the circumferential coil center of the first set of coils and the circumferential coil center of the second set of coils are respectively The coil center position for each phase, which coincides with each coil center position formed for each pole pitch over the entire circumference of the stator core, or A stator for a rotating electrical machine in which the coil center positions for each pole pitch are alternately displaced by the same amount in the circumferential direction on one side and the other side with respect to the coil center positions for each pole pitch.

2. On one side in the axial direction, a plurality of the coil segments are joined to each other in the stator coil, In each phase, the pairs of slots into which the pairs of coil segments to be joined are inserted are separated in the circumferential direction by a fixed number of slots. The stator for a rotating electrical machine according to claim 1.

3. The plurality of coil segments include, for each phase, a plurality of first coil segments and a plurality of second coil segments, The plurality of first coil segments are a plurality of center slots arranged on both sides in the circumferential direction around the coil center position for each pole pitch, and are inserted into a plurality of center slots forming a slot pitch corresponding to the pole pitch, The plurality of second coil segments are a plurality of pairs of slots arranged around the coil center position over the entire circumference of the stator core, and are inserted into a plurality of pairs of slots forming a slot pitch that is smaller than the pole pitch by two slots, The coil end portion formed by the first coil segments extends axially outward more than the coil end portion formed by the second coil segments. The stator for a rotating electrical machine according to claim 1.

4. The plurality of coil segments further include, for each phase, a plurality of third coil segments and a plurality of fourth coil segments, The plurality of third coil segments are inserted into a plurality of pairs of slots forming a slot pitch that is larger than the pole pitch by one slot, The plurality of fourth coil segments are inserted into a plurality of pairs of slots forming a slot pitch that is smaller than the pole pitch by one slot, When each set of three adjacent slots in the circumferential direction centered on the center slot is alternately the first set of three adjacent slots and the second set of three adjacent slots for each phase, In the first set, for each phase, the first coil piece, the third coil piece, and the fourth coil piece are inserted into the central slot of the first triple slot. In the first set, for each phase, only the first coil piece is inserted into the central slot of the second triple slot. In the second set, for each phase, only the first coil piece is inserted into the central slot of the first triple slot. In the second set, for each phase, the first coil piece, the third coil piece, and the fourth coil piece are inserted into the central slot of the second triple slot. The stator for a rotating electrical machine according to claim 3.

5. Each of the plurality of coil pieces includes a plurality of fifth coil pieces and a plurality of sixth coil pieces for each phase. The plurality of fifth coil pieces are inserted into a plurality of pairs of slots that form a slot pitch that is one slot larger than the pole pitch. The plurality of sixth coil pieces are inserted into a plurality of pairs of slots that form a slot pitch that is one slot smaller than the pole pitch. When each triple slot composed of three circumferentially adjacent slots centered on each of the plurality of central slots that form a pole pitch over the entire circumference of the stator core is alternately the first triple slot and the second triple slot in the circumferential direction for each phase, In the first set, for each phase, the fifth coil piece is inserted into the central slot of the first triple slot, and the fifth coil piece and the sixth coil piece are inserted into the slots on both sides of the second triple slot. In the second set, for each phase, the fifth coil piece is inserted into the central slot of the second triple slot, and the fifth coil piece and the sixth coil piece are inserted into the slots on both sides of the first triple slot. The stator for a rotating electrical machine according to claim 1.

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