Stator

Abstract

To provide a stator that can reduce a size of a coil end portion while avoiding interference between segment conductors.SOLUTION: A first phase coil 1 includes a first transition portion 15 and a second transition portion 16 that is disposed on an axial second side L2 from the first transition portion and overlaps with the first transition portion when viewed in an axial direction. The first transition portion 15 includes a first circumferential direction region E1, a second circumferential direction region E2, and a connection region E3. In the first circumferential direction region E1, a first bent portion 17 is formed between a second section K2 on a side of the connection region E3 and a first section K1, and an extension angle of the second section K2 is larger than an extension angle of the first section K1. In the second circumferential direction region E2, a second bent portion 18 is formed between a third section K3 on a side of the connection region E3 and a fourth section K4, and an extension angle of the third section K3 is larger than an extension angle of the fourth section K4.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a stator for a rotating electric machine, which includes a cylindrical stator core having a plurality of slots arranged in a circumferential direction, and three-phase coils wound around the stator core and through which AC currents of different phases flow. [Background technology]

[0002] Japanese Patent Application Laid-Open Publication No. 2018-88729 discloses a stator (10) including three-phase coils (stator windings (20)) formed using segment conductors (30) made of rectangular wires with a rectangular cross section (reference symbols in parentheses in the background art are those of this document). The segment conductors (30) are formed in a generally U-shape and have two housing portions (in-slot conductor portions (34, 35)) that correspond to the sides of the U and are housed in groove-shaped slots (18) formed along the axial direction of the stator core (12), and a bridge portion (coil end portion (36)) that corresponds to the bottom of the U and connects the two housing portions. The segment conductors (30) are arranged in the stator core (12) with the bridge portion protruding from the stator core (12) on one axial side of the stator core (12). On the other axial side of the stator core, lead portions (32, 33) corresponding to the lateral ends of the U-shape and extending from the housing portion protrude from the stator core (12). These lead portions (32, 33) are joined by welding or the like to the lead portions (32, 33) of other segment conductors (30), thereby forming a coil (the stator winding (20)).

[0003] The segment conductors 30 are wound around the stator core 12 so that the coil (the stator winding 20) is wound around the stator core 12 multiple times. That is, multiple segment conductors 30 are arranged radially in one slot 18. Each segment conductor 30 is arranged in the slot 18 between two accommodation portions (in-slot conductor portions 34, 35) with a gap therebetween, sandwiching multiple slots 18 between them. In this case, one accommodation portion and the other accommodation portion may be arranged at different radial positions. If a line connecting the same radial positions virtually in the circumferential direction is defined as a lane, the segment conductors are arranged on the stator core 12 while performing lane changes such that the lanes in which the two accommodation portions are arranged are changed at crossover portions. The segment conductors (30) arranged adjacent to each other in the circumferential direction are arranged such that one segment conductor (30) passes over (passes under when viewed from the other side) the other segment conductor (30) at the crossover portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-88729 Summary of the Invention [Problem to be solved by the invention]

[0005] The transition portion has a mountain-like shape with its central portion bulging away from the stator core (12). If the stator core (12) is also downsized to reduce the size of the rotating electric machine, the bending radius of the segment conductors (30) at the transition portion to form the mountain-like shape must also be reduced. However, as described above, when the segment conductors (30) are formed from rectangular wire, there is a limit to how small the bending radius can be. Furthermore, reducing the size of the stator core (12) also reduces the circumferential spacing of the slots (18). Therefore, when one segment conductor (30) at the transition portion passes over or passes under another segment conductor (30), there is a risk of interference between the segment conductors (30). It is possible to suppress such interference by forming the segment conductors (30) so that the height from the axial end face of the stator core (12) to the apex of the transition portion is increased. However, in this case, the axial length of the coil end portions protruding from the axial direction of the stator core (12) increases, hindering the miniaturization of the stator.

[0006] In view of the above background, it is desirable to realize a stator that can reduce the size of the coil end portion while avoiding interference between the segment conductors. [Means for solving the problem]

[0007] In view of the above, a stator for a rotary electric machine includes a cylindrical stator core having a plurality of slots arranged in a circumferential direction, and three-phase coils wound around the stator core and through which AC currents of mutually different phases flow, the phases of the AC current being designated as a first phase, a second phase, and a third phase in order of phase advance, the coil through which the AC current of the first phase flows being designated as a first-phase coil, the coil through which the AC current of the second phase flows being designated as a second-phase coil, and the coil through which the AC current of the third phase flows being designated as a third-phase coil, and the stator is wound around the axial center of the stator core. The direction in which the first phase coil is wound is defined as an axial direction, the direction perpendicular to the axis is defined as a radial direction, one side in the axial direction is defined as an axial first side, the other side in the axial direction is defined as an axial second side, one side in the circumferential direction is defined as a circumferential first side, and the other side in the circumferential direction is defined as a circumferential second side, and the first phase coil includes a first receiving portion received in a first slot that is the first of the slots, a second receiving portion received in a second slot that is the slot adjacent to the first slot on the second circumferential side, and a plurality of the slots disposed between the first slot and the second slot and spaced apart on the second circumferential side. a third accommodating portion accommodated in a third slot which is a slot adjacent to the third slot on the second circumferential side; a fourth accommodating portion accommodated in a fourth slot which is the slot adjacent to the third slot on the second circumferential side; a first transition portion connecting the first accommodating portion and the fourth accommodating portion on the first axial side with respect to the stator core; and a second transition portion connecting the second accommodating portion and the third accommodating portion on the first axial side with respect to the stator core, wherein the second transition portion is located on the second axial side of the first transition portion and is arranged to overlap with the first transition portion when viewed in the axial direction along the axial direction, A portion of the second phase coil that protrudes toward the first axial direction relative to the stator core is a second phase coil crossover portion, and a portion of the third phase coil that protrudes toward the first axial direction relative to the stator core is a third phase coil crossover portion, and the first crossover portion comprises: a first circumferential region that is a region on the first circumferential side; a second circumferential region that is a region on the second circumferential side relative to the first circumferential region; and a connection region that connects the first circumferential region and the second circumferential region and includes a radially bent portion that is bent in the radial direction, and the first circumferential region comprises:the second circumferential region comprises: a first section on the second axial side of the third-phase coil transition portion and overlapping with the third-phase coil transition portion in the axial view; and a second section on the first axial side of the second-phase coil transition portion and overlapping with the second-phase coil transition portion in the axial view; the second circumferential region comprises: a third section on the first axial side of the third-phase coil transition portion and overlapping with the third-phase coil transition portion in the axial view; and a fourth section on the second axial side of the second-phase coil transition portion and overlapping with the second-phase coil transition portion in the axial view; the second circumferential region is inclined as a whole toward the first axial side as it extends toward the second circumferential side, and the second circumferential region is inclined as a whole toward the second axial side as it extends toward the second circumferential side, and a first bent portion is formed between the first section and the second section, where the extension angle is an angle formed by the extension direction of the first crossover portion with respect to the circumferential direction, the second section has a larger extension angle than the first section, and a second bent portion is formed between the third section and the fourth section, where the extension angle is changed, and the third section has a larger extension angle than the fourth section.

[0008] According to this configuration, by arranging the second crossover portion on the second axial side of the first crossover portion and overlapping with the first crossover portion in the axial view, the first crossover portion and the second crossover portion are not aligned in the radial direction, which facilitates reducing the radial dimension of the coil end portion. Also, according to this configuration, by making the inclination angle of the second section larger than the inclination angle of the first section, it is possible to arrange the first crossover portion and the second crossover portion in a limited circumferential space while avoiding interference between the first section and the third phase coil crossover portion arranged on the first axial side of the first section, interference between the second section and the second phase coil crossover portion arranged on the second axial side of the second section, interference between the third section and the third phase coil crossover portion arranged on the second axial side of the third section, and interference between the fourth section and the second phase coil crossover portion arranged on the first axial side of the fourth section. Furthermore, by reducing the inclination of the first and fourth sections, it is easier to shorten the axial length of the first section toward the first axial side as it approaches the second circumferential side, and it is easier to shorten the axial length of the fourth section toward the first axial side as it approaches the first circumferential side. In other words, the overall length of the transition section toward the first axial side, in other words, the axial height of the coil, can be reduced. Therefore, it is easier to reduce the axial dimension of the coil end section. In this way, this configuration makes it possible to realize a stator that can reduce the size of the coil end section while avoiding interference between the segment conductors.

[0009] Further features and advantages of the stator of the rotating electrical machine will become apparent from the following description of exemplary, non-limiting embodiments thereof, which are given with reference to the drawings. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the appearance of a stator; [Figure 2] Schematic circuit block diagram showing an example of electrical connections to a coil. [Figure 3] A diagram showing the basic structure of a segment conductor [Figure 4] 1 is a plan view of a stator as viewed from a first axial side; [Figure 5] An enlarged perspective view of the stator viewed from the inside in the radial direction with the innermost segment conductor removed [Figure 6] Enlarged circumferential plan view showing an example of the arrangement of segment conductors as seen from the inside in the radial direction [Figure 7] An explanatory diagram showing the extension angle of the segment conductor [Figure 8] FIG. 1 is an enlarged plan view showing an example of the arrangement of segment conductors as viewed from a first axial side; [Figure 9] FIG. 10 is a partial perspective view showing an example of the arrangement of segment conductors in a comparative example; [Figure 10] FIG. 10 is a partial plan view showing an example of an arrangement of segment conductors according to a comparative example, as viewed from a first axial side; DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of a stator for a rotating electric machine will be described below with reference to the drawings. The perspective view of FIG. 1 shows a stator 8 in which a coil 84 (stator coil) is wound around a stator core 80. In the following description, the terms "axial direction L," "radial direction R," and "circumferential direction C" are defined with reference to the axis X of the stator core 80 around which the coil 84 is wound. As shown in FIG. 1, one side in the axial direction L is referred to as an axial first side L1, and the other side in the axial direction L (opposite the axial first side L1) is referred to as an axial second side L2. One side in the circumferential direction C is referred to as a circumferential first side C1, and the other side in the circumferential direction C (opposite the circumferential first side C1) is referred to as a circumferential second side C2. In the following description, the directions of the coil 84 and the segment conductors 4 forming the coil 84 refer to the directions when the coil 84 is wound around the stator core 80.

[0012] As shown in FIG. 2, an inverter INV is provided as an AC power source that supplies AC power to the rotating electric machine (stator 8). The inverter INV is connected between a DC power source 91 and the coil 84, and converts power between DC power and multi-phase (here, three-phase) AC power. The inverter INV is configured with a plurality of switching elements. The rotating electric machine can function as both an electric motor and a generator. When functioning as a generator, the generated AC power is converted by the inverter INV into DC power and supplied to the DC power source 91. The DC power source 91 is configured, for example, by a secondary battery (battery) such as a nickel-metal hydride battery or a lithium-ion battery, or an electric double-layer capacitor. When the rotating electric machine is used as a driving power source for a vehicle, the DC power source 91 is a high-voltage, large-capacity power source, and the rated power supply voltage is, for example, 200 to 400 V. A DC link capacitor 92 (smoothing capacitor) that smoothes the voltage on the DC side of the inverter INV (DC link voltage) is provided on the DC side of the inverter INV. The DC link capacitor 92 stabilizes the DC voltage (DC link voltage) that fluctuates in accordance with fluctuations in the power consumption of the rotating electrical machine.

[0013] 2, in this embodiment, the coil 84 is a Y-connection type in which each of the three phases (U-phase, V-phase, and W-phase) is connected at a neutral point. As will be described in detail later, the coils of the three phases (here, the first-phase coil 1, the second-phase coil 2, and the third-phase coil 3) are electrically connected to one another by a neutral point bus bar 88. Furthermore, each of the coils of the three phases is electrically connected to the three-phase AC outputs of the inverter INV by a power line bus bar 87. Note that the first-phase coil 1 may be any of the U-phase, V-phase, and W-phase, and similarly, the second-phase coil 2 and the third-phase coil 3 correspond to any of the U-phase, V-phase, and W-phase depending on the first-phase coil 1.

[0014] As shown in FIG. 1 , the coil 84 is wound around a stator core 80 in which a plurality of slots S extending in an axial direction L and a plurality of teeth T are formed in a circumferential direction C. The stator core 80 includes a yoke Y formed in an annular shape when viewed in the axial direction L, and a plurality of teeth T extending from the yoke Y toward a radially inner side R1 (the side where a rotor (not shown) is disposed in this embodiment). A groove-shaped slot S having a bottom on a radially outer side R2 is formed between two adjacent teeth T in the circumferential direction C. In this embodiment, the slot S is a semi-open slot, and an opening of the slot S on the radially inner side R1 is formed to have a smaller width in the circumferential direction C than a region of the slot S where the coil 84 is disposed. Here, the width of the opening of the slot S in the circumferential direction C is formed to be smaller than a long side length W1, which will be described later. The stator core 80 is formed using a magnetic material. For example, the stator core 80 is formed by stacking a plurality of magnetic plates (e.g., electromagnetic steel plates such as silicon steel plates). Alternatively, the stator core 80 is formed mainly from a compacted powder material obtained by compressing and molding powder of a magnetic material.

[0015] The coil 84 has a plurality of accommodating sections (a first end-side accommodating section 41, a second end-side accommodating section 42, and a specific accommodating section 63, which will be described later) that are each disposed within the slot S. In the present embodiment, the accommodating sections are disposed within the slot S so as to extend parallel to the axial direction L. As shown in FIGS. 1 and 4 , the coil 84 has a plurality of accommodating sections disposed within one slot S, with the arrangement area of one accommodating section in the radial direction R being one layer. In the present embodiment, the coil 84 has a six-layer winding structure, and within one slot S, the plurality of accommodating sections are divided into six layers and arranged in a row along the radial direction R. Therefore, in the present embodiment, a maximum of six accommodating sections are arranged lined up in the radial direction R within one slot S.

[0016] The coil 84 is formed by joining a plurality of segment conductors 4 as shown in Fig. 3. Each of the segment conductors 4 has lead portions (a first lead portion 43 and a second lead portion 44) at both ends in the extension direction of the segment conductor 4. The coil 84 is formed by sequentially joining the lead portions of the plurality of segment conductors 4 together.

[0017] Each of the segment conductors 4 is formed using a single continuous linear conductor. Here, "continuous" means that it is formed seamlessly and integrally in the extending direction. The linear conductor is made of a conductive material such as copper or aluminum. The surface of the linear conductor is covered with an insulating film made of an electrically insulating material such as resin (for example, enamel resin made of polyamideimide, etc.) except for the electrical connection points between different components.

[0018] As shown in Fig. 3, in this embodiment, the linear conductors constituting the segment conductors 4 are linear conductors (rectangular wires) having a rectangular cross section (rectangular in this embodiment) perpendicular to the extending direction. In this embodiment, the cross section of the segment conductor 4 is a rectangle with a long side length W1 and a short side length W2. Note that the cross section may be a square, and may also be a rectangle with arc-chamfered (R-chamfered) or linearly chamfered (C-chamfered) corners, or a rectangle where the absolute value of the difference between the size of the interior angle and 90 degrees is less than a predetermined angle (for example, 5 degrees or 10 degrees).

[0019] The segment conductors 4 include general segment conductors 5 that are continuously joined together to form the multiple coil body portions 83 that form the core of the coil 84, as described above, and specific segment conductors 6 that are joined to each end of the coil body portions 83. In this embodiment, the specific segment conductors 6 are segment conductors 4 that connect the power line bus bars 87 that supply AC power from the inverter INV to the coil body portions 83, and that connect the neutral point bus bar 88 that forms the neutral point of the coil 84 to the neutral points of the multiple coil body portions 83.

[0020] FIG. 3 schematically shows a general segment conductor 5 as a representative of the segment conductors 4. The general segment conductor 5 has an approximately U-shape. As shown in FIG. 3, the long-side side of a rectangular wire having a rectangular cross section corresponds to the front side of the approximately U-shape, and the short-side side of the rectangular wire corresponds to the side. The general segment conductor 5 has its U-shape formed by edgewise bending the short sides, except for a bent portion 49 in the radial direction R (such as a radial bent portion 19 (see FIGS. 4 to 8, etc.)) described later.

[0021] Each of the segment conductors 4 has a first lead portion 43 and a second lead portion 44 at both ends in the extension direction of the segment conductor 4. In the linearly extending portion of the approximately U-shape on the first lead portion 43 side, the first lead portion 43 and the first-end-side accommodating portion 41 are formed continuously and linearly, and in the linearly extending portion on the second lead portion 44 side, the second lead portion 44 and the second-end-side accommodating portion 42 are formed continuously and linearly. A transition portion 40 is formed at the bottom of the approximately U-shape so as to connect the first-end-side accommodating portion 41 and the second-end-side accommodating portion 42. The bent portion 49 described above is formed in the center of the transition portion 40. This bent portion 49 is formed by flatwise bending the long side.

[0022] The first end-side accommodating portion 41 and the second end-side accommodating portion 42 are portions accommodated in the slots S of the stator core 80. The distance between the first end-side accommodating portion 41 and the second end-side accommodating portion 42 in the circumferential direction C is N times (N is a natural number) the distance between the slots S adjacent to each other in the circumferential direction C. In the present embodiment, N=6 or N=4 (see FIG. 6 , etc.). As described above, the segment conductor 4 is arranged in six layers within one slot S, with the arrangement area of one accommodating portion (such as the first end-side accommodating portion 41 or the second end-side accommodating portion 42) in the radial direction R being one layer. In other words, within one slot S, the multiple accommodating portions are arranged in a row along the radial direction R. Therefore, the distance in the circumferential direction C differs between the radially inner side R1 and the radially outer side R2. Therefore, the distance in the circumferential direction C between the first end side accommodating portion 41 and the second end side accommodating portion 42 of the segment conductor 4 arranged on the radial outer side R2 is wider than the distance in the circumferential direction C between the first end side accommodating portion 41 and the second end side accommodating portion 42 of the segment conductor 4 arranged on the radial inner side R1.

[0023] The segment conductor 4 is inserted into the slots S along the axial direction L from the first axial side L1 toward the second axial side L2 of the stator core 80, from the side of the first lead portion 43 and the second lead portion 44. The crossover portion 40 is a portion that protrudes toward the first axial side L1 of the stator core 80 when the first-end-side accommodating portion 41 and the second-end-side accommodating portion 42 of the segment conductor 4 are accommodated in the slots S. The first lead portion 43 and the second lead portion 44 are portions that protrude toward the second axial side L2 of the stator core 80 when the first-end-side accommodating portion 41 and the second-end-side accommodating portion 42 of the segment conductor 4 are accommodated in the slots S. The protruding first lead portion 43 and the second lead portion 44 are bent in the circumferential direction C as indicated by the two-dot chain line in FIG. 3 and joined to the lead portions of other segment conductors 4 by welding or the like. The first lead portion 43 and the second lead portion 44 correspond to a joint portion 45 relative to the transition portion 40 .

[0024] Thus, protruding portions of the coils 84, known as coil end portions, are formed on the first axial side L1 and the second axial side L2 of the stator core 80. When distinguishing between the two, the coil end portion formed by the transition portion 40 on the first axial side L1 is referred to as the first coil end portion 85, and the coil end portion formed by the joint portion 45 on the second axial side L2 is referred to as the second coil end portion 86. The length from the first axial side end face 81 of the stator core 80 to the portion where the transition portion 40 projects most toward the first axial side L1 corresponds to the length in the axial direction L of the first coil end portion 85. Furthermore, the length from the second axial side end face 82 of the stator core 80 to the portion where the joint portion 45 projects most toward the second axial side L2 corresponds to the length in the axial direction L of the second coil end portion 86.

[0025] The coil 84 includes not only the general segment conductors 5 that form the coil body 83, but also specific segment conductors 6 that are electrically connected to a power line bus bar 87 that connects the coil body 83 to a power source (in this case, an inverter INV that supplies AC power) and a neutral bus bar 88 that connects different phases in the coil body 83. As shown in FIG. 1 , the specific segment conductor 6 has a specific accommodating portion 63 that is accommodated in a slot S of the stator core 80, an axially extending portion 64 that extends in the axial direction relative to the stator core 80, and a radially extending portion 65 that extends in the radial direction R on a first axial side L1 of the crossover portion 40 of the general segment conductor 5 and on a radially outer side R2 of the axially extending portion 64.

[0026] The specific segment conductors 6 also include a plurality of power line conductors 61 connected to an AC power supply (here, an inverter INV) and a plurality of neutral point conductors 62 for connecting neutral points of the coil main bodies 83. Radial extending portions 65 of the power line conductors 61 are arranged closer to the first axial side L1 than the radial extending portions 65 of the neutral point conductors 62.

[0027] As described above, each segment conductor 4 (general segment conductor 5) is arranged in the slots S at intervals between two accommodating sections (the first end-side accommodating section 41 and the second end-side accommodating section 42) with a plurality of slots S sandwiched therebetween. In this case, the first end-side accommodating section 41 and the second end-side accommodating section 42 may be arranged at different positions in the radial direction R. That is, the first end-side accommodating section 41 and the second end-side accommodating section 42 may be arranged in different layers (see FIG. 4 ). If layers formed by virtually connecting the same positions in the radial direction R in the circumferential direction C are defined as lanes in which the coil 84 extends in the circumferential direction C, the segment conductors 4 are arranged in the stator core 80 while performing lane changes in which the lanes in which the two accommodating sections are arranged are changed at the crossover section 40 (see FIGS. 4 , 5 , etc.). Therefore, when segment conductors 4 are arranged adjacent to each other in the circumferential direction C, one segment conductor 4 may climb over or pass under the other segment conductor 4 at the crossover section 40, as shown in FIG. 5 , etc.

[0028] The transition portion 40 is formed in a mountain shape with its central portion bulging in a direction away from the stator core 80. When reducing the size of a rotating electric machine, the stator core 80 also needs to be reduced in size, and attempts are sometimes made to reduce the bending radius when bending the segment conductors 4 at the transition portion 40 to form the mountain shape. However, as described above, when the segment conductors 4 are formed from rectangular wire and are formed into a U-shape by edgewise bending, there is a limit to how small the bending radius can be due to, for example, strength issues related to the bending stress of the conductor and issues regarding ensuring insulation in consideration of the effect on the insulating coating.

[0029] Furthermore, when the stator core 80 is made smaller, the spacing between the slots S in the circumferential direction C also becomes smaller. Therefore, when one segment conductor 4 passes over or passes under another segment conductor 4 in the transition portion 40, the segment conductors 4 may interfere with each other in an interference region F, as shown in the comparative examples in FIGS. 9 and 10 . For example, it is possible to suppress such interference by forming the segment conductors 4 so that the height from the axial end face (here, the first axial side end face 81) of the stator core 80 to the apex of the transition portion 40 is increased, making it easier for the segment conductors 4 to pass under each other. However, in this case, the length in the axial direction L of the coil end portion (here, the first coil end portion 85) protruding in the axial direction L of the stator core 80 becomes longer, which hinders the downsizing of the stator 8.

[0030] Therefore, in this embodiment, by devising the shape of the segment conductors 4 (general segment conductors 5), a stator 8 is realized that can avoid interference between the segment conductors 4 while reducing the size of the coil end portion (first coil end portion 85).

[0031] As described above, the stator 8 of this embodiment includes a cylindrical stator core 80 having a plurality of slots S arranged in the circumferential direction C, and three-phase coils 84 wound around the stator core 80 and through which AC currents of mutually different phases flow. Here, the phases of the AC current are referred to as a first phase, a second phase, and a third phase in order of phase advance (e.g., "U phase, V phase, W phase," "V phase, W phase, U phase," and "W phase, U phase, V phase"). The coil 84 through which the first-phase AC current flows is referred to as a first-phase coil 1, the coil 84 through which the second-phase AC current flows is referred to as a second-phase coil 2, and the coil 84 through which the third-phase AC current flows is referred to as a third-phase coil 3.

[0032] As shown in FIG. 6, the first phase coil 1 includes a first accommodating portion 11 accommodated in the first slot S1, a second accommodating portion 12 accommodated in the second slot S2, which is the slot S adjacent to the first slot S1 on the second circumferential side C2, a third accommodating portion 13 accommodated in the third slot S3, which is the slot S arranged spaced apart on the second circumferential side C2 with multiple slots S sandwiched between it and the second slot S2, a fourth accommodating portion 14 accommodated in the fourth slot S4, which is the slot S adjacent to the third slot S3 on the second circumferential side C2, a first crossover portion 15 connecting the first accommodating portion 11 and the fourth accommodating portion 14 to the stator core 80 on the first axial side L1, and a second crossover portion 16 connecting the second accommodating portion 12 and the third accommodating portion 13 to the stator core 80 on the first axial side L1. Although the winding method of the coil 84 is not limited to this, in the example shown in Fig. 6, the coil 84 is wound using short-pitch winding. Here, the third slot S3 is arranged with three slots S between it and the second slot S2. The first crossover portion 15 connects the first housing portion 11 and the fourth housing portion 14, which are arranged six slot pitches apart, and the second crossover portion 16 connects the second housing portion 12 and the third housing portion 13, which are arranged four slot pitches apart.

[0033] The first crossover portion 15 and the second crossover portion 16 are collectively referred to as the first-phase coil crossover portion 10. The first-phase coil 1 includes a first first-phase coil 1a and a second first-phase coil 1b. The first crossover portion 15 is the first-phase coil crossover portion 10 of the first first-phase coil 1a, and the second crossover portion 16 is the first-phase coil crossover portion 10 of the second first-phase coil 1b. The second crossover portion 16 is located on the second axial side L2 of the first crossover portion 15 and is arranged so as to overlap with the first crossover portion 15 in the axial direction. This embodiment illustrates a configuration in which the entire second crossover portion 16 overlaps with the first crossover portion 15 in the axial direction. However, a configuration in which only a portion of the second crossover portion 16 overlaps with the first crossover portion 15 in the axial direction may also be used.

[0034] In this way, the second crossover portion 16 is positioned on the second axial side L2 of the first crossover portion 15 and at a position overlapping with the first crossover portion 15 when viewed in the axial direction, so that the first crossover portion 15 and the second crossover portion 16 are not aligned in the radial direction R, making it easier to reduce the radial dimension of the first coil end portion 85.

[0035] Furthermore, the portion of the second-phase coil 2 that protrudes toward the first axial side L1 with respect to the stator core 80 is referred to as a second-phase coil crossover portion 20, and the portion of the third-phase coil 3 that protrudes toward the first axial side L1 with respect to the stator core 80 is referred to as a third-phase coil crossover portion 30. Similar to the first-phase coil 1, the second-phase coil 2 also includes a first second-phase coil 2a and a second second-phase coil 2b, and the third-phase coil 3 also includes a first third-phase coil 3a and a second third-phase coil 3b. The first second-phase coil 2a and the second second-phase coil 2b each include a second-phase coil crossover portion 20, and the first third-phase coil 3a and the second third-phase coil 3b each include a third-phase coil crossover portion 30.

[0036] The first transition portion 15 includes a first circumferential region E1 which is a region on the first circumferential side C1, a second circumferential region E2 which is a region on the second circumferential side C2 relative to the first circumferential region E1, and a connection region E3 which connects the first circumferential region E1 and the second circumferential region E2 and includes a radial bending portion 19 which is bent in the radial direction R.

[0037] The first circumferential region E1 includes a first section K1 on the second axial side L2 of the third-phase coil transition portion 30 and overlapping with the third-phase coil transition portion 30 in the axial view, and a second section K2 on the first axial side L1 of the second-phase coil transition portion 20 and overlapping with the second-phase coil transition portion 20 in the axial view. Note that a section (K20) where the first transition portion 15 is on the first axial side L1 of the second-phase coil transition portion 20 and overlaps with the second-phase coil transition portion 20 in the axial view also exists in the connection region E3. The second section K2 is set as part of this section (K20).

[0038] The second circumferential region E2 also includes a third section K3 on the first axial side L1 of the third-phase coil transition portion 30 and overlapping with the third-phase coil transition portion 30 in the axial view, and a fourth section K4 on the second axial side L2 of the second-phase coil transition portion 20 and overlapping with the second-phase coil transition portion 20 in the axial view. Note that a section (K30) in which the first transition portion 15 is on the first axial side L1 of the third-phase coil transition portion 30 and overlaps with the third-phase coil transition portion 30 in the axial view also exists in the connection region E3. The third section K3 is set as part of this section (K30).

[0039] The first circumferential region E1 is inclined as a whole toward the first axial side L1 as it extends toward the second circumferential side C2, and the second circumferential region E2 is inclined as a whole toward the second axial side L2 as it extends toward the second circumferential side C2. Here, the angle formed by the extension direction of the first crossover portion 15 with respect to the circumferential direction C is defined as the extension angle.

[0040] As shown in FIG. 6, a first bent portion 17 is formed between the first section K1 and the second section K2, at which the extension angle of the first jumper portion 15 changes. The first bent portion 17 is formed by edgewise bending the short side of the segment conductor 4 in the axial direction L. The second section K2 has a larger extension angle than the first section K1. In other words, as shown in FIG. 7, a second extension angle θ2, which is the extension angle of the first jumper portion 15 on the second circumferential side C2 relative to the first bent portion 17 (the extension angle in the second section K2), is larger than a first extension angle θ1, which is the extension angle of the first jumper portion 15 on the first circumferential side C1 relative to the first bent portion 17 (the extension angle in the first section K1).

[0041] As shown in FIG. 6, a second bend 18 is formed between the third section K3 and the fourth section K4, at which the extension angle of the first jumper portion 15 changes. The second bend 18 is formed by edgewise bending the short side of the segment conductor 4 in the axial direction L. The third section K3 has a larger extension angle than the fourth section K4. That is, as shown in FIG. 7, a third extension angle θ3, which is the extension angle of the first jumper portion 15 on the first circumferential side C1 relative to the second bend 18 (the extension angle in the third section K3), is larger than a fourth extension angle θ4, which is the extension angle of the first jumper portion 15 on the second circumferential side C2 relative to the second bend 18 (the extension angle in the fourth section K4).

[0042] In this embodiment, the shape of the first crossover portion 15 is symmetrical when viewed in the radial direction, the first extension angle θ1 and the fourth extension angle θ4 are the same angle (θ10), and the second extension angle θ2 and the third extension angle θ3 are the same angle (θ20). That is, the axial first-side extension angle θ20, which is the extension angle of the first crossover portion 15 on the axial first side L1 relative to the first bent portion 17 and the second bent portion 18, is larger than the axial second-side extension angle θ10, which is the extension angle of the first crossover portion 15 on the axial second side L2 relative to the first bent portion 17 and the second bent portion 18.

[0043] The shape of the first bridge portion 15 does not necessarily have to be symmetrical in a radial view. That is, the extension angles only need to satisfy the relationships "θ2>θ1" and "θ3>θ4," and the first extension angle θ1 and the fourth extension angle θ4 do not have to be the same angle (axial second-side extension angle θ10). Similarly, the second extension angle θ2 and the third extension angle θ3 do not have to be the same angle (axial first-side extension angle θ20).

[0044] By making the second extension angle θ2, which is the inclination angle (extension angle) of the second section K2, larger than the first extension angle θ1, which is the inclination angle of the first section K1, the position of the first section K1 in the axial direction L is retracted to the second axial side L2. As a result, it becomes easier to ensure a space between the third-phase coil crossover portion 30, which is arranged on the first axial side L1 with respect to the first section K1, and the first section K1 (first crossover portion 15), and it becomes easier to avoid interference between the first section K1 and the third-phase coil crossover portion 30, which is arranged on the first axial side L1 with respect to the first section K1.

[0045] Furthermore, by making the second extension angle θ2, which is the inclination angle (extension angle) of the second section K2, larger than the first extension angle θ1, which is the inclination angle of the first section K1, the position of the second section K2 in the axial direction L is moved toward the first axial side L1, and therefore the second crossover section 16, which is located closer to the second axial side L2 than the second section K2, can also be moved toward the first axial side L1. As a result, it is easier to ensure a space between the second-phase coil crossover section 20, which is located closer to the second axial side L2 than the second section K2 and the region (section) of the second crossover section 16 that overlaps with the second section K2 in the axial direction, and the second section K2 and the region (section) of the second crossover section 16 that overlaps with the second section K2 in the axial direction. This makes it easier to avoid interference between the second section K2 and the second-phase coil crossover section 20, which is located closer to the second axial side L2 than the second section K2.

[0046] Furthermore, by making the third extension angle θ3, which is the inclination angle (extension angle) of the third section K3, larger than the fourth extension angle θ4, which is the inclination angle of the fourth section K4, the position of the third section K3 in the axial direction L is moved toward the first axial side L1, and therefore the second crossover portion 16, which is located closer to the second axial side L2 than the third section K3, can also be moved toward the first axial side L1. As a result, it becomes easier to ensure space between the third-phase coil crossover portion 30, which is located closer to the second axial side L2 than the third section K3 and the region (section) of the second crossover portion 16 that overlaps with the third section K3 in the axial direction, and the third section K3 and the region (section) of the second crossover portion 16 that overlaps with the third section K3 in the axial direction. This makes it easier to avoid interference between the third section K3 and the third-phase coil crossover portion 30, which is located closer to the second axial side L2 than the third section K3.

[0047] Furthermore, by making the third extension angle θ3, which is the inclination angle (extension angle) of the third section K3, larger than the fourth extension angle θ4, which is the inclination angle of the fourth section K4, the position of the fourth section K4 in the axial direction L is retracted to the second axial side L2. As a result, it becomes easier to ensure a space between the second-phase coil crossover portion 20, which is arranged on the first axial side L1 with respect to the fourth section K4, and the fourth section K4 (first crossover portion 15), and it becomes easier to avoid interference between the fourth section K4 and the second-phase coil crossover portion 20, which is arranged on the first axial side L1 with respect to the fourth section K4.

[0048] That is, according to this embodiment, the first transition portion 15 and the second transition portion 16 can be arranged in a limited space in the circumferential direction C while avoiding interference between the first phase coil 1 and the second phase coil 2 and between the first phase coil 1 and the third phase coil 3.

[0049] In the comparative example illustrated in FIG. 9 , the inclination angle (extension angle) of the transition portion 40 is constant and does not change. The axial second-side extension angle θ10 (first extension angle θ1, fourth extension angle θ4) is smaller than the extension angle (θ9) of the transition portion 40 in the comparative example illustrated in FIG. 9 , and the axial first-side extension angle θ20 (second extension angle θ2, third extension angle θ3) is larger than the extension angle (θ9) of the transition portion 40 in the comparative example. Therefore, in the comparative example, as described above, when a transition portion 40 climbs over or passes under another transition portion 40, sufficient space cannot be secured, and the transition portions 40 may interfere with each other in the interference region F. However, in the present embodiment, compared to the comparative example, when two segment conductors 4 intersect, interference between the segment conductors 4 can be avoided and the length of the transition portion 40 in the axial direction L can be reduced.

[0050] Furthermore, by reducing the inclination angles of the first section K1 and the fourth section K4, it is easy to shorten the length in the axial direction L toward the axial first side L1 as it approaches the circumferential second side C2 in the first section K1, and it is easy to shorten the length in the axial direction L toward the axial first side L1 as it approaches the circumferential first side C1 in the fourth section K4. That is, the length of the entire transition portion 40 toward the axial first side L1, in other words, the height in the axial direction L of the coil 84, can be kept short. Therefore, it is easy to reduce the dimension in the axial direction L of the first coil end portion 85.

[0051] In the above, the first section K1, the second section K2, the third section K3, the fourth section K4, etc. are exemplified as partially overlapping when viewed in the axial direction. However, the overlap in the definition of these sections is not limited to partial overlap, but also includes cases where they completely overlap.

[0052] As shown in FIG. 6 (sections are not shown, but see FIG. 5 for a three-dimensional view), the first section K1 is disposed on the radially inner side R1 of the second-phase coil transition portion 20 so as to overlap with the second-phase coil transition portion 20 in a radial view. The second section K2 is disposed on the radially inner side R1 of the third-phase coil transition portion 30 so as to overlap with the third-phase coil transition portion 30 in a radial view. The third section K3 is disposed on the radially outer side R2 of the second-phase coil transition portion 20 so as to overlap with the second-phase coil transition portion 20 in a radial view. The fourth section K4 is disposed on the radially outer side R2 of the third-phase coil transition portion 30 so as to overlap with the third-phase coil transition portion 30 in a radial view. Note that attention is focused here on the second-phase coil 2 and the third-phase coil 3, which are disposed in the same layer as the first-phase coil 1 (here, two layers adjacent in the radial direction R).

[0053] As described above, according to this embodiment, the first and second crossover portions 15 and 16 of the first phase coil 1, the second phase coil crossover portion 20, and the third phase coil crossover portion 30 can be appropriately arranged in a limited space, thereby facilitating the miniaturization of the first coil end portion 85 of the stator 8.

[0054] As shown in FIG. 6, the connection region E3 is disposed so as to extend along the circumferential direction C as a whole, and the radial bending portion 19 is disposed at a position that does not overlap with either the second phase coil crossover portion 20 or the third phase coil crossover portion 30 when viewed in the radial direction.

[0055] This configuration makes it easier to reduce the dimension of the first coil end portion 85 in the radial direction R compared to when the radially bent portion 19 is positioned so as to overlap at least one of the second-phase coil crossover portion 20 and the third-phase coil crossover portion 30 as viewed in the radial direction. Furthermore, in this embodiment, the radially bent portion 19 formed in the connection region E3 is formed by bending only in the radial direction R, and the segment conductor 4 is not bent in the axial direction L. That is, the bent portion can be formed so that the bending directions of the segment conductor 4 do not combine in the connection region E3 (so that edgewise bending and flatwise bending are not combined), which makes it difficult to apply a large mechanical load to the insulating coating applied to the surface of the segment conductor 4, making it easier to ensure insulation.

[0056] As described above, the conductor constituting the coil 84 is a coated conductor wire having a rectangular cross section and an insulating coating formed on the surface. A rectangular wire can be more easily made to have a higher space factor than a round wire, which facilitates downsizing of the stator 8. Furthermore, the insulating coating makes it easier to wind the coil 84 around the stator core 80 with a high space factor while ensuring insulation. Furthermore, a rectangular wire can easily maintain its shape once formed. Therefore, for example, the first and second crossover portions 15 and 16 of the first-phase coil 1, the second-phase coil crossover portion 20, and the third-phase coil crossover portion 30 can be easily formed into a predetermined shape, and these can be easily aligned and appropriately arranged in a limited space.

[0057] As described above, the conductor constituting the coil 84 has a rectangular cross-sectional shape in which the dimension in the axial direction L (long side length W1) is greater than the dimension in the radial direction R (short side length W2) at the first and second cross-sectional portions 15, 16. Therefore, the first bent portion 17 and the second bent portion 18 are axially bent portions bent in the axial direction L.

[0058] Because the first bent portion 17 and the second bent portion 18 are not bent in the radial direction R, the radial size of the coil end portion of the stator is prevented from increasing. Furthermore, because the first bent portion and the second bent portion are bent in the axial direction, the axial length of the first crossover portion is shortened. Therefore, it is easy to reduce the size of the coil end portion of the stator.

[0059] In the above, the coil 84 configured using the segment conductors 4 (general segment conductors 5) and the stator 8 including the coil 84 have been described as a representative of the first phase coil 1 in relation to the second phase coil 2 and the third phase coil 3. The first phase coil 1, the second phase coil 2, and the third phase coil 3 have the same structure, and the second phase coil 2 and the third phase coil 3 also have the same configuration as that described above as a representative of the first phase coil 1. [Explanation of symbols]

[0060] 1: first phase coil, 2: second phase coil, 3: third phase coil, 8: stator, 11: first housing portion, 12: second housing portion, 13: third housing portion, 14: fourth housing portion, 15: first crossover portion, 16: second crossover portion, 17: first bent portion, 18: second bent portion, 19: radially bent portion, 20: second phase coil crossover portion, 30: third phase coil crossover portion, 40: crossover portion, 49: bent portion, 80: stator core, 84: coil, C: circumferential direction, C1: first circumferential side, C2: second circumferential side, E1: first circumferential region, E2: second circumferential region, E3: connection region, K1 : first section, K2: second section, K3: third section, K4: fourth section, L: axial direction, L1: first axial side, L2: second axial side, R: radial direction, R1: radially inner side (radially inner side), R2: radially outer side (radially outer side), S: slot, S1: first slot, S2: second slot, S3: third slot, S4: fourth slot, X: axis, θ1: first extension angle (extension angle of first section), θ2: second extension angle (extension angle of second section), θ3: third extension angle (extension angle of third section), θ4: fourth extension angle (extension angle of fourth section)

Claims

1. A stator for a rotating electric machine includes a cylindrical stator core having a plurality of slots arranged in a circumferential direction, and three-phase coils wound around the stator core and through which AC currents of mutually different phases flow, The phases of the AC current are referred to as a first phase, a second phase, and a third phase in order of phase advance, the coil through which the AC current of the first phase flows is referred to as a first phase coil, the coil through which the AC current of the second phase flows is referred to as a second phase coil, and the coil through which the AC current of the third phase flows is referred to as a third phase coil, the direction along the axis of the stator core is referred to as an axial direction, the direction perpendicular to the axis is referred to as a radial direction, one side in the axial direction is referred to as an axial first side, the other side in the axial direction is referred to as an axial second side, one side in the circumferential direction is referred to as a circumferential first side, and the other side in the circumferential direction is referred to as a circumferential second side, the first phase coil includes: a first accommodating portion accommodated in a first slot, which is the first of the slots; a second accommodating portion accommodated in a second slot, which is the slot adjacent to the first slot on the second circumferential side; a third accommodating portion accommodated in a third slot, which is the slot arranged spaced apart on the second circumferential side with a plurality of slots interposed between the first accommodating portion and the second slot; a fourth accommodating portion accommodated in a fourth slot, which is the slot adjacent to the third slot on the second circumferential side; a first crossover portion connecting the first accommodating portion and the fourth accommodating portion on the first axial side with respect to the stator core; and a second crossover portion connecting the second accommodating portion and the third accommodating portion on the first axial side with respect to the stator core, the second bridge portion is located on the second axial side of the first bridge portion and is arranged to overlap with the first bridge portion as viewed in the axial direction, a portion of the second phase coil that protrudes toward the first axial direction relative to the stator core is a second phase coil crossover portion, and a portion of the third phase coil that protrudes toward the first axial direction relative to the stator core is a third phase coil crossover portion, the first transition portion includes a first circumferential region that is a region on the first circumferential side, a second circumferential region that is a region on the second circumferential side with respect to the first circumferential region, and a connection region that connects the first circumferential region and the second circumferential region and includes a radially bent portion that is bent in the radial direction, the first circumferential region includes a first section that is on the second axial side of the third-phase coil transition portion and overlaps with the third-phase coil transition portion in the axial direction, and a second section that is on the first axial side of the second-phase coil transition portion and overlaps with the second-phase coil transition portion in the axial direction, the second circumferential region includes a third section on the first axial side of the third phase coil transition portion and overlapping with the third phase coil transition portion in the axial direction, and a fourth section on the second axial side of the second phase coil transition portion and overlapping with the second phase coil transition portion in the axial direction, the first circumferential region is inclined as a whole toward the axial first side as it extends toward the circumferential second side, and the second circumferential region is inclined as a whole toward the axial second side as it extends toward the circumferential second side, The angle formed by the extension direction of the first bridge portion with respect to the circumferential direction is defined as an extension angle, a first bent portion is formed between the first section and the second section, at which the extension angle changes, and the extension angle of the second section is larger than that of the first section; A stator, wherein a second bent portion where the extension angle changes is formed between the third section and the fourth section, and the extension angle of the third section is larger than that of the fourth section.

2. the first section is disposed radially inward of the second phase coil crossover portion and overlaps with the second phase coil crossover portion as viewed in the radial direction, the second section is disposed radially inward of the third phase coil transition portion and overlaps with the third phase coil transition portion as viewed in the radial direction, the third section is disposed radially outward of the second phase coil crossover portion and overlaps with the second phase coil crossover portion as viewed in the radial direction, 2. The stator according to claim 1, wherein the fourth section is disposed radially outward of the third phase coil crossover portion and overlaps with the third phase coil crossover portion as viewed in the radial direction.

3. The connection region is arranged along the circumferential direction as a whole, 3. The stator according to claim 2, wherein the radially bent portion is disposed at a position that does not overlap with either the second phase coil crossover portion or the third phase coil crossover portion when viewed in the radial direction.

4. 4. The stator according to claim 1, wherein the conductor constituting the coil is a coated conductor wire having a rectangular cross section and an insulating coating formed on a surface thereof.

5. The conductor has a rectangular cross section in the first transition portion and the second transition portion, the cross section having a dimension in the axial direction greater than a dimension in the radial direction, The stator according to claim 4 , wherein the first bent portion and the second bent portion are axially bent portions bent in the axial direction.

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