Stator for rotating electric machines

Abstract

Stator (20) for a rotating electric machine, wherein the stator (20) has: a hollow cylindrical stator core (30) with a longitudinal axis (o) and a plurality of slots (31) formed in a radial inner surface of the stator core (30) and spaced apart in the circumferential direction of the stator core (30); and a stator coil (40) consisting of a plurality of electrical conductor wires (50) mounted on the stator core (30), where each of the electrical conductor wires (50) has first, second, ..., n-th slot sections (51) and first, second, ..., (n-1)-th turning sections (52), where n is an integer not less than 4, the first to nth slot sections (51) are sequentially included in p of the slots of the stator core (30), where p is an integer not greater than n, the first to (n-1)th turning sections (52) are arranged alternately on opposite axial sides of the stator core (30) outside the slots (31) to connect corresponding adjacent pairs of the first to nth slot sections (51), each of the electrical conductor wires (50) also has first and second end sections (53a, 53b), wherein the first end section (53a) is closer to the first slot section (51A) than one of the slot sections (51) of the electrical conductor wire (50), and the second end section (53b) is closer to the nth slot section (51L) than one of the slot sections (51) of the electrical pair, the first slot sections (51) of the electrical conductor wires (50) are arranged radially on the outermost and the nth slot sections (51) are arranged radially on the innermost in the slots (31) of the stator core (30), for each of the electrical conductor wires (50) the radial distances from the longitudinal axis of the stator core (30) to the first to the nth slot section (51) of the electrical wire decrease successively in the sequence from the first slot section (51A) to the nth slot section (51L), the stator coil (40) is a multi-phase stator coil (40) which consists of a plurality of phase windings (43), each of the phase windings (43) of the stator coil (40) is formed from at least two of the electrical conducting wires (50), and the first end section (53a) of one of the electrical conductor wires (50) is connected to the second end section (53b) of the other electrical conductor wire (50).

Description

BACKGROUND OF THE INVENTION 1. Technical field of the invention

[0001] The present invention relates to stators for rotating electrical machines, which are used, for example, in motor-driven vehicles as electric motors and electric generators. 2. Description of the state of the art

[0002] WO 2008 / 108351 A1 discloses a wiring material for forming a stator conductor, which includes slot housing portions to be arranged in the slots of a stator core, and bending portions that protrude from the slots to the outside of the stator core and connect the slot housing portions arranged in the circumferentially different slots. The winding portions are individually formed on the two axial sides of the stator core. A crank portion, to which no torsion follows, is formed at the substantially central portion of the winding portions. Step portions are formed at the protruding portions of the winding portions that protrude from the slots to the outside of the stator core.In addition, the step portions of the wiring material individually have two step portions formed between the crank portion of the substantially central portion and the step portions formed at the projecting portions of the turn portions.

[0003] US 2009 / 0001841 A1 discloses a distributed-winding stator using a rectangular conductor as a coil, featuring a miniaturized coil end and reduced current density to achieve a miniaturized high-performance rotary electric machine. The distributed-winding stator is formed by wave-winding a conductor source wire with a rectangular cross-section, the wire being bent so that the wall portions at both ends are offset according to the width of the source wire and the length is within the range of the distances between adjacent slots, and by inserting the wave-winding coil into slots of the stator.

[0004] Stators for rotating electrical machines are already known, which include a hollow cylindrical stator core and a stator coil. The stator core has a plurality of slots formed in the radial inner surface of the stator core and spaced apart in the circumferential direction of the stator core. The stator coil consists of a plurality of electrical conductor wires mounted on the stator core.

[0005] Furthermore, a method for manufacturing a stator is disclosed in Japanese Unexamined Patent Application Publication No. JP 2001-145286 A, for example. According to this method, U-phase, V-phase, and W-phase windings of the stator coil are configured with a rectangular cross section and have an overall shape such that, when unwound in a plane, the windings extend meanderingly in the shape of a crank, thereby improving the space factors of the electric wires in the slots of the stator core. Further, each of the U-phase, V-phase, and W-phase windings is spirally wound by a predetermined number of turns to form a stator coil having a hollow cylindrical shape.

[0006] However, with the above method, each of the electric wires (or electric conductors) forming the U-phase, V-phase, and W-phase windings of the stator coil is required to have a certain length. Accordingly, a long or large forming machine is required to form the electric wires. Furthermore, because the electric wires are long, it is difficult to handle the electric wires during stator manufacturing. Therefore, it is difficult to ensure high productivity and low cost of the stator. Furthermore, since the electric wires are spirally wound and accommodated in the slots of the stator core, interference due to springback of the electric wires may occur between the stator coil and a rotor arranged radially inside the stator.Accordingly, the stator coil may be damaged due to this interference, which negatively affects the longevity of the stator. SUMMARY OF THE INVENTION

[0007] The present invention has been made in view of the above-mentioned problems of the prior art. Accordingly, it is an object of the present invention to solve the above-mentioned problems.

[0008] This object is achieved by the stator having the features of claim 1. Further advantageous developments and embodiments of the invention are the subject of the subsequent claims.

[0009] According to one aspect of the present invention, a stator for a rotating electrical machine is provided, which includes a hollow cylindrical stator core and a stator coil. The stator core has a plurality of slots formed in a radially inner surface of the stator core and spaced apart in the circumferential direction of the stator core. The stator coil consists of a plurality of electrical wires mounted on the stator core. Each of the electrical wires has first, second, ..., n-th slot portions and first, second, ..., (n-1)-th turn portions, where n is an integer not less than 4. The first to n-th slot portions are sequentially accommodated in p of the slots of the stator core, where p is an integer not greater than n.The first to (n-1)th turn portions are alternately arranged on opposite axial sides of the stator core outside the slots to connect corresponding adjacent pairs of the first to nth slot portions. Each of the electric wire leads further has first and second end portions. The first end portion is closer to the first slot portion than one of the slot portions of the electric wire lead; the second end portion is closer to the nth slot portion than one of the slot portions of the electric wire lead. The first slot portions of the electric wire leads are radially outermost, and the nth slot portions are radially innermost, in the slots of the stator core. The stator coil is a multi-phase stator coil composed of a plurality of phase windings. Each of the phase windings of the stator coil is formed of at least two of the electric wire leads.The first end portion of one of the two electrical lead wires is connected to the second end portion of the other electrical lead wire.

[0010] With the above configuration, since each of the phase windings of the stator coil is formed of at least two electric wires, it is possible to shorten the length of each of the electric wires. Accordingly, the electric wires can be formed using a smaller molding machine and can be easily handled during stator manufacturing. As a result, it is possible to achieve high productivity and low cost for the stator. Furthermore, since the first slot portions of the electric wires are arranged radially outward and the n-th slot portions are arranged radially inward in the slots of the stator core, the first and second end portions of each of the electric wires can be respectively drawn or removed from the radially inner and radially outer peripheries of the stator core. Accordingly, each corresponding orA corresponding pair of the first and second end portions of the electrical wires can be respectively pulled or removed from two substantially spaced-apart locations. This improves the flexibility of the connection of the electrical wires. SHORT DESCRIPTION OF THE CHARACTERS

[0011] The present invention will be better understood from the following detailed description and the accompanying figures of preferred embodiments of the invention, wherein the specific embodiments are not intended to limit the invention but are intended merely for illustration and better understanding.

[0012] The attached drawing shows: Fig. 1 is a perspective view showing the overall configuration of the stator for rotating electrical machines according to the first embodiment of the invention; Fig. 2 a top view of the stator; Fig. 3 a side view of the stator; Fig. 4 a plan view of the stator core of the stator; Fig. 5 is a plan view of one of the stator core segments which together form the stator core; Fig. 6 a perspective view of the stator coil of the stator; Fig. 7 a side view of the stator coil; Fig. 8 a plan view of the stator coil; Fig. 9 a bottom view of the stator coil; Fig. 10A is a cross-sectional view illustrating the configuration of electric wires forming the stator coil; Fig. 10B is a cross-sectional view showing a modification of the electrical wires used in Fig. 10A; Fig. 11A is a plan view of one of the electrical lead wires; Fig. 11B is a front view of one of the electrical lead wires; Fig. 12A is a perspective view illustrating a turning portion of one of the electric wires; Fig. 12B is a perspective view illustrating a plurality of turning portions of the electric wires adjacent to each other; Fig. 13A is a bottom view of the electrical wire assembly consisting of the electrical wires for forming the stator coil; Fig. 13B is a front view of the electrical lead wire assembly; Fig. 13C is a perspective view illustrating one of the electrical lead wires in the electrical lead wire assembly after the electrical lead wire assembly is rolled into a hollow cylindrical shape; Fig. 14 a circuit diagram of the stator coil; Fig. 15 is a schematic view illustrating the arrangement of the radially outermost slot portion of each of the electric wire in the stator core; Fig. 16 is a schematic view illustrating the manner of extension of the electric wire marked (U1-4') as viewed along the longitudinal axis O of the stator core; Fig. 17 is a tubular diagram showing both the number of the electric wire disposed at the radially outermost layer and the number of the electric wire disposed at the radially innermost layer in each of the slots of the stator core; Fig. 18 is a schematic view illustrating the connection between those of the electric wire which together form a V-phase winding of the stator coil, viewed from the radial inside of the stator core; Fig. 19A is a front view of an electric wire for forming the stator coil according to a first modification of the invention; Fig. 19B is a front view of an electric wire for forming the stator coil according to a second modification of the invention; Fig. 20A is a front view of an electric wire for forming the stator coil according to a fourth modification of the invention; Fig. 20B is a front view of an electric wire for forming the stator coil according to a fourth modification of the invention; Fig. 21 is a perspective view showing a turning portion of an electric wire for forming a stator coil according to a fifth modification of the invention; Fig. 22A is a plan view of an electric wire for forming the stator coil according to a sixth modification of the invention; Fig. 22B is a front view of the electric wire according to the sixth modification; Fig. 23 is a plan view of a stator according to the second embodiment of the invention; Fig. 24 is a side view of the stator according to the second embodiment, Fig. 25 is a plan view of the stator according to the second embodiment, wherein a connection is omitted; Fig. 26 is a side view of the stator according to the second embodiment, wherein a connection is omitted; Fig. 27 a plan view of the connection; Fig. 28 a side view of the connection; Fig. 29 a bottom view of the connection; Fig. 30 is a schematic view illustrating the manner of connecting the electric wires according to the seventh modification of the invention; and Fig. 31 is a schematic view showing the manner of connecting the electric wires according to the eighth modification of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Preferred embodiments of the present invention will be described below with respect to the Fig. 1 to 31. It should be noted that, for the sake of clarity and better understanding, identical components with identical functions in different embodiments of the invention have been provided with identical reference numerals in the figures, where possible.

[0014] Fig. 1 to 3 together illustrate the overall configuration of a stator 20 according to a preferred embodiment of the invention. The stator 20 is intended for use in, for example, a rotating electric machine configured to function as both an electric motor and an electric generator in a motor-driven vehicle. The rotating electric machine further includes a rotor (not shown) rotatably disposed so as to be surrounded by the stator 20. The rotor includes a plurality of permanent magnets forming a plurality of magnetic poles on a radially outer peripheral portion of the rotor and opposing a radially inner peripheral portion of the stator. The polarities of the magnetic poles alternate between north and south in the circumferential direction of the rotor. Moreover, in the present embodiment, eight magnetic poles are formed in the rotor (i.e., four north poles and four south poles).

[0015] As in the Fig. As shown in Figures 1 to 3, the stator 20 includes a hollow cylindrical stator core 30 and a three-phase stator coil 40 consisting of a plurality of (e.g., 48 in the present embodiment) electrical wires 50 mounted on the stator core 30. Furthermore, the stator 20 may include an insulating paper layer interposed between the stator core 30 and the stator coil 40.

[0016] The stator core 30 has as shown Fig. 4, a plurality of slots 31 are formed in the radially inner surface of the stator core 30 and spaced at a fixed pitch in the circumferential direction of the stator core 30. For each of the slots 31, the depth direction of the slots 31 is the same as a radial direction of the stator core 30. In the present embodiment, two slots 31 are provided per magnetic pole of the rotor, which has eight magnetic poles per phase of the three-phase stator coil 40. Accordingly, the total number of slots 31 provided in the stator core 30 is 48 (i.e., 2x8x3).

[0017] In addition, in the present embodiment, the stator core 30 consists of, for example, 24 stator core segments 32 as shown in Fig. 5. The stator core segments 32 are connected to each other so as to be adjacent in the circumferential direction of the stator core 30, with each of the stator core segments 32 defining one of the slots 31 therein. Furthermore, each circumferentially adjacent pair of the stator core segments 32 together defines another slot 31 therebetween. Each of the stator core segments 32 further includes two tooth portions 33 extending radially to form one of the slots 31 therebetween, and a rear core portion 34 disposed radially outwardly of the tooth portions 33 to connect them. In addition, a cylindrical outer rim or rim part 37 is fitted to the radially outer surfaces of the stator core segments 32 (see Fig. 1 to 3).

[0018] In the present embodiment, each of the stator core segments 32 is formed by laminating a plurality of magnetic steel layers with a plurality of insulating films therebetween. It should be noted that conventional metal layers may also be used instead of the magnetic metal layers.

[0019] Fig. 6 to 9 together illustrate the configuration of the stator coil 40. In the present embodiment, the stator coil 40 is manufactured by stacking the 48 electric wire leads 50 as described later to form a band-shaped wire lead assembly 45 as shown in FIGS. Fig. 13A to 13B, and then roll up the electrical lead wire assembly 45 in a hollow cylindrical shape.

[0020] As in the Fig. 6 to 9, the stator coil 40 as a whole comprises a straight part 41 to be received in the slots 31 of the stator core 30, and a pair of coil end parts 42 formed respectively on opposite axial sides of the straight part 41 and to be arranged outside the slots 31. Furthermore, on one axial side of the straight part 41, U-phase, V-phase, and W-phase output terminals and U-phase, V-phase, and W-phase neutral terminals of the stator coil 40 protrude from the annular axial end surface of the coil end part 42, and a plurality of crossing parts 70 of the electric wire 50 cross the axial end surface from the radial inside to the radial outside of the annular axial end surface to connect corresponding pairs of the electric wire 50.

[0021] Each of the electrical wires 50 for forming the stator coil 40 is as shown in Fig. 10A, it is configured with an electrical conductor 67 and an insulating layer 68 covering the outer surface of the electrical conductor 67. In the present embodiment, the electrical conductor 67 is made of copper and has a substantially rectangular cross-section. The insulating layer 68 is composed of a two-layer structure to include an inner layer 68a and an outer layer 68b. The thickness of the insulating sheath 68 (i.e., the sum of the thicknesses of the inner and outer layers 68a and 68b) is set to a value between 100 and 200 µm.

[0022] With such a thickness of the two-layer structured insulation sheath 68, it is possible to reliably insulate the electrical wires 50 from each other without relying on the insulating paper layers between them. However, it is also possible to apply insulating paper layers between the electrical wires 50 to further improve the electrical insulation therebetween.

[0023] Furthermore, the outer layer 68b is made of an insulating material such as nylon. The inner layer 68a is made of a thermoplastic resin with a higher glass transition temperature than the outer layer 68b, or an insulating material with no glass transition temperature, such as a polyamide-imide resin. Therefore, the outer layers 68b of the electrical lead wires 50 solidify before the inner layers 68a due to the heat generated by the operation of the rotating electrical machine. Accordingly, the surface hardness of the outer layers 68b is increased, thereby improving the electrical insulation between the electrical lead wires 50.

[0024] Furthermore, as in Fig. As shown in Figure 10B, each of the electrical lead wires 50 may also include a fusible sheath 69 to cover the outer surface of the insulating sheath 68; the fusible sheath 69 may be made of, for example, an epoxy resin. In this case, the protective sheaths 69 of the electrical lead wires 50 are melted before the insulating sheaths 68 by the heat generated during operation of the rotating electrical machine, thereby bonding these portions of the electrical lead wires 50, which are housed in the same slots 31 of the stator core 30. As a result, these portions of the electrical lead wires 50 become a solid body, thereby improving mechanical strength. Furthermore, the outer layers 68b of the insulating sheaths 68 of the electrical lead wires 50 may also be made of PPS (polyphenylene sulfide).

[0025] Fig. 11A and Fig. 11B together illustrate the shape of each of the electrical lead wires 50 before the electrical lead wires 50 are stacked to form the ribbon-shaped lead wire assembly 45.

[0026] As in the Fig. 11A and Fig. 11B, each of the electric wires 50 is wave-shaped to include a plurality of slot portions 51 and a plurality of turn portions 52. The slot portions 51 are spaced apart at predetermined intervals in the longitudinal direction Y of the electric wire 50 and extend perpendicular to the longitudinal direction Y. Each of the slot portions 51 is to be received in a corresponding one of the slots 31 of the stator core 30. Each of the turn portions 52 extends to contact a corresponding adjacent pair of slot portions 51 and is to be disposed outside the slots 31 of the stator core 30.

[0027] More specifically, the plurality of slot portions 51 include at least a first slot portion 51A, a second slot portion 51B, and a third slot portion 51C. The first, second, and third slot portions 51A, 51B, and 51C are respectively received in three different slots 31 of the stator core 30; the three slots 31 are circumferentially spaced at a pitch of six slots 31. Meanwhile, the plurality of turn portions 52 include at least a first turn portion 52A and a second turn portion 52B. The turn portion 52A connects the first and second slot portions 51A and 51B and is to be arranged on an axial side of the stator core 30 outside the slots 31. The second turning portion 52B connects the second and third slot portions 51B and 51C and is to be arranged on the other axial side of the stator core 30 outside the slots 31.

[0028] More specifically, in the present embodiment, as shown in the Fig. 11A to 11B, the plurality of slot portions 51 include first to twelfth slot portions 51A to 51L, which are sequentially received in eight slots 31 circumferentially spaced at a pitch of six slots 31. That is, there are twelve slot portions 51 in each of the electric wire 50. Meanwhile, a plurality of turn portions 52 include first to eleventh turn portions 52A to 52K, each connecting a corresponding adjacent pair of the slot portions 51A to 51L, and are to be alternately arranged on the opposite axial side of the stator core 30 outside the slots 31. That is, the number of turn portions 52 in each of the electric wire 50 is 11.

[0029] Furthermore, the pitches X between the slot portions 51A to 51L in the longitudinal direction Y of the electric wire 50 gradually decrease in a direction from the first slot portion 51A to the twelfth slot portion 51L. That is, X1>X2>X3>X4>X5>X6>X7>X8>X9>X10>X11. Furthermore, the predetermined pitches X1 to X11 are set based on the circumferential pitches between the eight slots 31 of the stator core 30 in which the slot pitches 51A to 51L are to be accommodated.

[0030] Each of the electric wire 50 further includes a pair of connecting portions 53a and 53b formed respectively at opposite ends of the electric wire 50 for connecting the electric wire 50 to other electric wire 50. The connecting portion 53a is connected to the first slot portion 51A via a half-turn portion 52M extending from the first slot portion 51A and inward (ie, to the right in Fig. 11B) in the longitudinal direction Y of the electric wire 50. The length of the half-turn portion 52M is substantially half as long as the first turn portion 52A. Accordingly, the connecting portion 53a is inward (ie, to the right in Fig. 11B) in the longitudinal direction Y from the first slot portion 51A by the length of the half-turn portion 52M. On the other hand, the connecting portion 53b is connected to the twelfth slot portion 51L via a half-turn portion 52N extending from the twelfth slot portion 51L, and inwardly (ie, to the left in Fig. 11B) in the longitudinal direction Y of the electric wire 50. The length of the half-turn section 52N is substantially half as long as the eleventh turn section 52K. Accordingly, the connecting section 53b is inward (ie, to the left in Fig. 11B) is spaced apart in the longitudinal direction Y from the twelfth slot portion 51L by the length of the half-turn portion 52N. Furthermore, the connecting portion 53b is formed to include one of the above-described crossover parts 70.

[0031] Furthermore, as in Fig. 11A, each of the turning portions 52 has, substantially at its center, a crank-shaped portion 54 bent to space the turning portion 52 in a direction perpendicular to both the longitudinal direction Y of the electric wire 50 and the extending direction of the slot portions 51. Thus, the electric wire 50 is stepped by the crank-shaped portions 54 to space the slot portions 51 in a direction perpendicular to both the longitudinal direction Y and the extending direction of the slot portions. It should be noted that the term "crank-shaped" is used only to describe the overall shape of the portions 54, and this term does not limit the interior angles between adjacent portions of the portions 54 to a 90° angle.

[0032] Regarding the Fig. 12A and Fig. 12B, after forming the stator coil 40 with the electric lead wires 50 and arranging the stator core 30 to the stator coil 40, each of the turning portions 52 (ie, 51A to 52K) of the electric lead wires 50 is spaced apart by the crank-shaped part 54 formed therein in the radial direction of the stator core 30. In addition, although this is not shown in the Fig. 12A and Fig. 12B, each of the crank-shaped parts 54 formed in the turning portions 52 of the electric wires 50 extends parallel to a corresponding axial end surface 30a of the stator core 30.

[0033] Furthermore, in the present embodiment, the amount of radial spacing created by each of the crank-shaped parts 54 is set equal to the radial thickness of the slot portions 51 of the electric wires 50. Here, the amount of radial spacing created by each of the crank-shaped parts 54 is defined as the difference in radial position between the opposite ends of the crank-shaped part 54. Accordingly, the difference in radial position between each adjacent pair of the slot portions 51 connected by a corresponding one of the turn portions 52 for each of the electric wires 50 is equal to the radial thickness (i.e., thickness in the radial direction of the stator core 30) of the slot portions 51.

[0034] By adjusting the value or amount of radial spacing as shown above, it is possible to arrange each adjacent pair of the turning portions 52 of the electric lead wires 50 in close contact with each other, as shown in Fig. 12B. As a result, the radial thickness of the coil end portions 42 of the stator coil 40 can be minimized. Furthermore, it is possible for each adjacent pair of turn portions 52 of the electrical wires 50 to extend in the circumferential direction of the stator core 30 without interference therebetween.

[0035] In addition, as described in the Fig. 12A and Fig. 12B, each of the turning portions 52 of the electric wire 50 has a pair of shoulder portions 55 adjacent to the pair of slot portions 51 connected by the turning portion 52, both extending perpendicularly to the pair of slot portions 51 (or parallel to the corresponding axial end surface 30a of the stator core 30). Therefore, with the shoulder portions 55, the protruding height of each of the turning portions 52 from the corresponding axial end surface 30a of the stator core 30 can be reduced. As a result, the axial length of the coil end portions 42 of the stator coil 40 can be reduced. Furthermore, the coil end portions 42 of the stator coil 40 are each composed of these turning portions 52 of the electric wire 50, which are arranged on the same axial side of the stator core 30.

[0036] Further, in the present embodiment, the following spatial relationship is set: d1 ≤ d2, where d1 is the length of each of the shoulder parts 55 of the electric wire 50 in the circumferential direction of the stator core 30, and d2 is the distance between each circumferentially adjacent pair of the slots 31 of the stator core 30.

[0037] Specifically, with the above relationship, it is possible to prevent interference between each pair of the turn portions 52 of the electric wire 50, which respectively protrude from a circumferentially adjacent pair of the slots 31 of the stator core 30. Accordingly, it is possible to prevent both the axial lengths and radial thicknesses of the coil end portions 42 of the stator coil 40 from increasing, thereby preventing the above-described interference.

[0038] Furthermore, as described in the Fig. 12A and Fig. 12B, each of the turning portions 52 of the electric wire 50 further includes two shoulder portions 56 between the crank-shaped portion 54 and each of the shoulder portions 55. Accordingly, each of the turning portions 52 of the electric wire 50 includes one crank-shaped portion 54, two shoulder portions 55, and four shoulder portions 56. Each of the shoulder portions 56, like the shoulder portions 55, extends perpendicular to the slot portions 51 (or parallel to the corresponding axial end surface 30a of the stator core 30). Accordingly, with the shoulder portions 56, the protruding height of each of the turning portions 52 from the corresponding axial end surface 30a of the stator core 30 can be further reduced. As a result, the axial length of the coil end portions 42 of the stator coil 40 can be further reduced.

[0039] In addition, each of the turning portions 52 of the electric wire 50 may be considered to be stepped on both sides of the crank-shaped part 54 to reduce its protruding height from the corresponding axial end surface 33a of the stator core 30.

[0040] In the present embodiment, the stator coil 40 is provided with the 48 electrical wires 50 as shown in the Fig. 11A and Fig. 11B. It should be noted that the intersection portions 70 may be omitted from some of the electric wires 50 for designing the configuration of the U-phase, V-phase, and W-phase output terminals and the U-phase, V-phase, and W-phase neutral terminals in the stator coil 40. However, in any case, it is preferable that all of the electric wires 50 have the same shape at least between the lead portions 53a and 53b.

[0041] When forming the stator coil 40, the 48 electrical wires 50 are first stacked one upon another such that the longitudinal directions Y of the electrical wires 50 are parallel to each other, and the first slot portions 51a of the electrical wires 50 are spaced apart from each other in the longitudinal direction Y by a slot pitch of the stator core 30 (ie, the circumferential length between the centers of each adjacent pair of the slots 31 of the stator core 30). Accordingly, the band-shaped conductive wire assembly 45 is formed as shown in FIGS. Fig. 13A and Fig. 13B. The assembly 45 has a pair of stepped surfaces 45a formed respectively at opposite longitudinal ends of the assembly 45 and facing in opposite directions.

[0042] In addition, the first electrical lead wire 50 (hereinafter designated by 50a) is as shown in Fig. 13A, is arranged in the stack of electrical wires 50 at the left end at the bottom of the electrical wire assembly 45; the last electrical wire 50 (hereinafter designated by 50b) is arranged in the stack of electrical wires 50 at the right end at the very top of the assembly 45.

[0043] The band-shaped conductor wire assembly 45 is then rolled up to form a hollow cylinder with a constant radial thickness in the circumferential direction. More specifically, the band-shaped conductor wire assembly 45 is wound as shown in Fig. 13A, is rolled up from the left end in the counterclockwise direction Z, thereby bringing the two stepped surfaces 45a into full contact with each other.

[0044] Accordingly, each of the electrical wires 50 included in the assembly 45 is Fig. 13C, wound one and a half turns in a spiral shape. Accordingly, each of the electrical wires 50 in the finally obtained stator 20 extends around the axis O of the stator core 30, viewed along the axis O of the stator core 30 (see Fig. 16).

[0045] Thereafter, the corresponding pairs of connecting portions 53a and 53b of the electric wire 50 are connected to each other, for example, by welding. As a result, the stator coil 40 is formed as shown in the Fig. 6 to 9 are shown.

[0046] In the stator coil 40, the turning portions 52 of the electrical wires 50 located radially outward do not protrude radially outward from the slot portions 51 of the electrical wires 51 located radially outward in the slots 31 of the stator core 30. Accordingly, the outer diameter of the coil end portions 42 of the stator coil 40 can be limited.

[0047] As described above, each of the turning portions 52 of the electrical wires 50 includes, substantially at its center, the crank-shaped part 54, by which the turning portion 52 is radially spaced by the radial thickness of the slot portions 51. Accordingly, for each of the electrical wires 50, the difference in radial position between each adjacent pair of the slot portions 51 connected by corresponding turning portions 52 is equal to the radial thickness of the slot portions 51. Moreover, in each of the electrical wires 50, the first slot portion 51A is located radially outermost, while the twelfth slot portion 51L is located radially innermost; the predetermined distances X between the slot portions 51A to 51L become continuously smaller in the direction from the first slot portion 51A to the twelfth slot portion 51L (see Fig. 11B). Accordingly, those slot portions 51 of the electrical wires 50 which are stacked in the radial direction of the stator coil 40 (or in the radial direction of the stator core 30) can be aligned straight in the radial direction, thereby enabling the stator coil 40 to have a substantially perfectly hollow cylindrical shape as shown in the Fig. 6 and Fig. 7.

[0048] Furthermore, all the i-th slot portions 51 of the 48 electric wires 50 are arranged in the 48 slots 31 of the stator core 30, respectively, at the same radial positions, where i = 1, 2, ..., 12. For example, all the first slot portions 31A of the 48 electric wires 50 are arranged in the 48 slots 31, respectively, and are radially outermost in the corresponding slots 31; all the twelve slot portions 51L of the 48 electric wires 50 are arranged in the 48 slots 31, respectively, and are radially innermost in the corresponding slots 31. With the above arrangement of the slot portions 51 of the electric wires 50, both the outer and inner diameters of the stator coil 40 can be uniformly arranged in the circumferential direction of the stator core 30.

[0049] In the present embodiment, the stator coil 40 is as shown in Fig. 14, is formed as a three-phase coil consisting of three phase windings (i.e., U-phase, V-phase, and W-phase windings) 43. Each of the U-phase, V-phase, and W-phase windings 43 is formed by serially connecting 16 electric wires 50. Further, the U-phase output and neutral terminals are respectively formed at opposite ends of the U-phase winding 43; the V-phase output and neutral terminals are respectively formed at the opposite ends of the V-phase winding 43; and the W-phase output and neutral terminals are respectively formed at the opposite ends of the W-phase winding 43. Further, the U-phase, V-phase, and W-phase windings 43 are Y-connected to define a neutral point and a star point therebetween, respectively. That is, the U-phase, V-phase and W-phase neutral terminals of the U-phase, V-phase and W-phase windings 43 are connected to each other at the neutral point.star point. Accordingly, the three-phase AC power or three-phase AC current is input or output from the stator coil 40 via the U-phase, V-phase, and W-phase output terminals.

[0050] In the Fig. 15 and Fig. 16, the intersections between the twelve dashed circles and 48 radially extending dashed lines indicate the positions of the slot sections 51 of the electrical conductor wires 50. Furthermore, between the positions of the slot sections 51, only the radially outermost and radially innermost are marked by rectangles.

[0051] The Fig. 15 and Fig. 16, it can be seen that in the present embodiment, in each of the slots 31 of the stator core 30, the slot portions 51 of the electric wire 50 are radially stacked in twelve layers.

[0052] Furthermore, Nos. 1 to 48 of the slots 31 of the stator core 30 are in the Fig. 15 and Fig. 16 is shown radially outside the 48 radially extending dashed lines. In addition, Fig. 15, each of the 48 electrical wires 50 is marked or labeled radially outside the slot 31 in which the first slot portion 51A of the electrical wires 50 is located radially outward (ie, located in the twelfth layer in the slot 31); each of the 48 electrical wires 50 is also marked radially inward in the slot 31 in which the twelfth slot portion 51L of the electrical wires 50 is located radially inward (ie, in or at the first layer in the slot 31).

[0053] In the present embodiment, each of the U-phase, V-phase, and W-phase windings 43 of the stator coil 40 is formed with first and second electric wire groups, each consisting of eight electric wires 50. The slot portions 51 of the electric wire 50 of the first group are housed in eight common slots 31 of the stator core 30. Similarly, the slot portions 51 of the electric wire 50 of the second group are housed in another eight common slots 31 of the stator core 30. That is, the slot portions 51 of the electric wire 50 of the first group are housed in different slots 31 from the slot portions 51 of the electric wire 50 of the second group.

[0054] For example, the U-phase winding 43 is formed with a first electric wire group consisting of the electric wire wires 50 labeled (U1-1) to (U1-4) and (U1-1') to (U1-4'), and a second electric wire group consisting of the electric wire wires 50 labeled (U2-1) to (U2-4) and (U2-1') to (U2-4'). The slot portions 51 of the (U1-1) to (U1-4) and (U1-1') to (U1-4') electric wire wires 50 are accommodated in the slots 31 Nos. 1, 7, 13, 19, 25, 31, 37, and 43 of the stator core 30. On the other hand, the slot portions 51 of the (U2-1) to (U2-4) and (U2-1') to (U2-4') electric wire 50 are accommodated in the slots 31 Nos. 2, 8, 14, 20, 26, 32, 38 and 44 of the stator core 30.

[0055] Fig. 15 illustrates, from an axial side of the stator core 32, the arrangement of each of the 48 electric wire 50, using the (U1-1) electric wire 50 as an example. More specifically, in Fig. 15, the positions of the slotted portions 51 of the (U1-1) electric wire 50 are indicated by black rectangles; those turning portions 52 of the (U1-1) electric wire 50 which are arranged on one axial side of the stator core 30 (i.e., on the “front side” of the paper surface of Fig. 15), are indicated by circumferentially extending solid lines; and those of the turning portions 52 of the (U1-1) electric wire 50 which are arranged on the other axial side of the stator core 30 (ie, on the “back” side of the paper surface of Fig. 15), are marked by circumferentially extending dash-dotted lines with two dots. As can be seen from Fig. 15, the first slot portion 51A for the (U1-1) electric wire 50 is arranged at the twelfth layer (i.e., the radially outermost layer) in the No. 1 slot 31; the twelfth slot portion 51L is arranged at the first layer (i.e., the radially innermost layer) in the No. 19 slot 31; the first to twelfth slot portions 51A to 51L are circumferentially spaced at a pitch of six slots; and the radial portions of the slot portions 51A to 51L are successively offset radially inward by one layer.

[0056] Fig. Fig. 16 illustrates the arrangement of each of the 48 electric wire 50, viewed from the other axial side of the stator core 30, using the (U1-4') electric wire 50 as an example. More specifically, the positions of the slot portions 51 of the (U1-4') electric wire 50 in Fig. 16 are indicated by black rectangles; those of the connecting portions 52 of the (U1-4') electric wire 50 which are arranged on the other axial side of the stator core 30 (ie, on the front side of the paper surface of Fig. 16) are indicated by circumferentially extending solid lines; and those of the turning portions 52 of the (U1-4') electric wire 50 which are arranged on one axial side of the stator core 30 (ie, on the back side of the paper surface of Fig. 16), are marked by circumferentially extending dash-dotted lines with two dots. As in Fig. 16, the first slot portion 51A for the (U1-4') electric wire 50 is arranged at the twelfth layer in slot 31 No. 43; the twelfth slot portion 51L is arranged in the first layer in slot 31 No. 13; the first to twelfth slot portions 51A to 51L are circumferentially spaced at a pitch of six slots; and the radial positions of the slot portions 51A to 51L are successively offset by one layer.

[0057] As described above, in the present embodiment, the stator core 30 has the 48 slots 31 formed therein, and the stator coil 40 is formed with the 48 electric wires 50. The electric wires 50 are mounted on the stator core 30 so as to be offset from each other in the circumferential direction of the stator core 30 by a slot pitch of the stator core 30. Accordingly, the first slot portions 51A of the 48 electric wires 50 are respectively arranged at the radially outermost layers (i.e., the twelfth layers) in the 48 slots 31; the twelve slot portions 51L of the 48 electric wires 50 are respectively arranged at the radially innermost layers (i.e., the first layers) in the 48 slots 31.

[0058] Fig. 17 illustrates both the marking of the electrical conduction wire 50 disposed at the radially outermost layer and the marking of the electrical conduction wire 50 disposed at the radially innermost layer in each of the slots 31 of the stator core 30.

[0059] In the present embodiment, for each of the 48 electric wires 50 constituting the stator coil 40, the radial distances from the axis O of the stator core 30 to the slot portions 51 of the electric wire 50 become successively smaller from the first slot portion 51A to the twelfth slot portion 51L. Moreover, the difference in the radial distance from the axis O of the stator core 30 between each adjacent pair of the slot portions 51 connected by one of the corresponding turn portions 52 for each of the 48 electric wires 50 is equal to the radial thickness of the slot portions 51.

[0060] Related to Fig. 16, for example, for the (U1-4') electric wire 50, the following relationship is satisfied: r43>r1>r7>r13. Here, r43 represents the radial distance from the axis O of the stator core 30 to the first slot portion 51A located at the twelfth layer in slot 31 No. 43; r1 represents the radial distance from the axis O to the second slot portion 51B located at the eleventh layer in slot 31 No. 1; r7 represents the radial distance from the axis O to the third slot portion 51C located at the tenth layer in slot 31 No. 7; and r13 represents the radial distance from the axis O of the fourth slot portion 51D located at the ninth layer in slot 31 No. 13. Furthermore, the radial distances r43, r1, r7 and r13 become successively smaller according to the radial thickness of the slot sections 51.

[0061] Next, regarding the Fig. 14 and 17 to 18 describe the manner of serially connecting the sixteen electric wires 50 for forming the V-phase winding 43 of the stator coil 40. It should also be noted that the electric wires 50 for forming the U-phase and W-phase windings 43 of the stator coil 40 are connected in the same manner as those for forming the V-phase winding 43.

[0062] As in Fig. 14, the U-phase winding 43 is connected by serially connecting the (V1-1) to (V1-4), (V1-1') to (V1-V4'), (V2-1) to (V2-4) and (V2-1') to (V2-4') electrical lead wires 50.

[0063] More specifically, the U-phase output terminal is connected to the side end of the first slot portion 51A of the (V1-1) electric wire 50. As shown in the Fig. 17 and Fig. 18, in the (V1-1) electric wire 50, the first slot portion 51A is arranged at the radially outermost layer (ie, the twelfth layer) in slot 31 No. 5 of the stator core 30, while the twelfth slot portion 51L is arranged at the radially innermost layer (ie, the first layer) in slot 31 No. 23.

[0064] The side end of the first slot portion 51A of the (V1-2) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V1-1) electric wire 50. Furthermore, in the (V1-2) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 17, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 35.

[0065] The side end of the first slot portion 51A of the (V1-3) ​​electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V1-2) electric wire 50. Furthermore, in the (V1-3) ​​electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 29, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 47.

[0066] The side end of the first slot portion 51A of the (V1-4) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V1-3) ​​electric wire 50. Furthermore, in the (V1-4) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 41, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 11.

[0067] The side end of the first slot portion 51A of the (V2-1) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V1-4) electric wire 50. Furthermore, in the (V2-1) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 6, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 24.

[0068] The side end of the first slot portion 51A of the (V2-2) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V2-1) electric wire 50. Furthermore, in the (V2-2) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 18, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 36.

[0069] The side end of the first slot portion 51A of the (V2-3) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V2-2) electric wire 50. Furthermore, in the (V2-3) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 30, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 48.

[0070] The side end of the first slot portion 51A of the (V2-4) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V2-3) electric wire 50. Furthermore, in the (V2-4) electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 72, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 12.

[0071] The side end of the twelfth slot portion 51L of the (V2-4) electric wire 50 is connected to the side end of the twelfth slot portion 51L of the (V2-4') electric wire 50. Moreover, in the (V2-4') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 48, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 18.

[0072] The side end of the twelfth slot portion 51L of the (V2-3') electric wire 50 is connected to the side end of the first slot portion 51A of the (V2-4') electric wire 50. Moreover, in the (V2-3') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 36, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 6.

[0073] The side end of the twelfth slot portion 51L of the (V2-2') electric wire 50 is connected to the side end of the first slot portion 51A of the (V2-3') electric wire 50. Moreover, in the (V2-2') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 24, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 42.

[0074] The side end of the twelfth slot portion 51L of the (V2-1') electric wire 50 is connected to the side end of the first slot portion 51A of the (V2-2') electric wire 50. Moreover, in the (V2-1') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 12, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 30.

[0075] The side end of the twelfth slot portion 51L of the (V1-4') electric wire 50 is connected to the side end of the first inner slot portion 51A of the (V2-1') electric wire 50. Moreover, in the (V1-4') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 47, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 17.

[0076] The side end of the twelfth slot portion 51L of the (V1-1') electric wire 50 is connected to the side end of the first slot portion 51A of the (V1-4') electric wire 50. Moreover, in the (V1-3') electric wire 50, the first slot portion 51A is located at the radially outermost layer in the slot 31 No. 35, while the twelfth slot portion 51L is located at the radially innermost layer in the slot 31 No. 5.

[0077] The side end of the twelfth slot portion 51L of the (V1-2') electric wire 50 is connected to the side end of the first slot portion 51A of the (V1-3') electric wire 50. Moreover, in the (V1-2') electric wire 50, the first slot portion 51A is located at the radially outermost layer in slot 31 No. 23, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 41.

[0078] The side end of the twelfth slot portion 51L of the (V1-1') electric wire 50 is connected to the side end of the first slot portion 51A of the (V1-2') electric wire 50. Furthermore, in the (V1-1') electric wire 50, the first slot portion 50A is located at the radially outermost layer in slot 31 No. 11, while the twelfth slot portion 51L is located at the radially innermost layer in slot 31 No. 29. Furthermore, the side end of the first slot portion 51A of the (V1-1') electric wire 50 is connected to the V-phase neutral terminal of the stator coil 40.

[0079] Further, as described above, each of the electric wires 50 has the connecting portion 53a at its side end of the first slot portion 51A and the connecting portion 53b at its side end of the twelfth slot portion 51L (see Fig. 11A to 11B). The connecting portion 53a is connected to the first slot portion 51A via the half-turn portion 52M, and the connecting portion 53e is connected to the twelfth slot portion 51L via the half-turn portion 52N. The connecting portion 53b also has an intersection part 70 formed therein. In the present embodiment, the connection between the electric wires 50 is established by welding corresponding pairs of connecting portions 53a and 53b of the electric wires 50.

[0080] For example, the (V1-1) electric wire 50 has the first slot portion 51A in the radially outermost layer in the No. 5 slot 31 of the stator core 30, and the twelfth slot portion 51L in the radially innermost layer in the No. 23 slot 31. The connecting portion 53b of the (V1-1) electric wire 50 is spaced by the length of the half-turn portion 52N in the circumferential direction of the stator core 30, from the No. 23 slot 31 to the vicinity of the No. 20 slot 31. On the other hand, the (V1-2) electric wire 50 has the first slot portion 51A in the radially outermost layer in slot 31 No. 17, and the twelfth slot portion 51L at the radially innermost layer in slot 31 No. 35. The connecting portion 53a of the (V1-2) electric wire 50 is spaced by the length of the half-turn portion 52M in the circumferential direction of the stator core 30 from slot 31 No. 17 to the vicinity of slot 31 No. 20.Further, the connecting portion 53b of the (V1-1) electric wire 50 is as shown in Figs. Fig. 6 to 9, the connecting portion 53b of the (V1-1) electric wire 50 is bent radially outward substantially at a right angle to extend from the radially inner periphery of the stator coil 40 to the connecting portion 53a of the (V1-2) electric wire 50 disposed on the radially outer periphery of the stator coil 40; then, the connecting portion 53b of the (V1-1) electric wire 50 is welded onto the connecting portion 53a of the (V1-2) electric wire 50. That is, the side end of the twelfth slot portion 51L of the (V1-1) electric wire 50 is connected to the side end of the first slot portion 51A of the (V1-2) electric wire 50 by welding.

[0081] Furthermore, in the present embodiment, all the corresponding pairs of the connecting portions 53a and 53b of the electric wires 50 are welded radially outside the radially outermost turning portions 52 of the electric wires 50. At this end, each of the connecting portions 53b of the electric wires 50 is configured to include the crossover part 70 that intersects the annular axial end surface of the stator coil 40 (more specifically, the annular axial end surface of the coil end part 42 of the stator coil 40, which is composed of the turning portions 52 of the electric wires 50) from the radially inner to the radially outer side of the axial end surface. Accordingly, it is possible to prevent the twelfth slot portions 51L of the electric wire 50, which are arranged radially inward in the slots 31 of the stator core 30, from projecting radially inward.As a result, it is possible to reliably prevent the stator coil 40 from interfering with the rotor of the rotating electrical machine arranged radially inside the stator 20.

[0082] Further, each of the crossover parts 70 of the electric wires 50, as shown in the present embodiment in Fig. 8, is crank-shaped and includes a pair of radially extending end portions 70a and 70b. With such a shape, it is possible to facilitate bending of the connecting portions 53b of the electrical wires 50 to form the crossover parts 70, and to establish welding of the corresponding pairs of the connecting portions 53a and 53b of the electrical wires 50.

[0083] In addition, the crossover parts 70 as in the Fig. 6 and Fig. 8, on the annular axial end surface of the stator coil 40, substantially 3 / 4 of the entire angular range or circumferential range of the axial end surface is arranged; the entire angular range is 360°. In the remaining 1 / 4 of the entire angular range, the V-phase neutral terminal, the W-phase output terminal, the U-phase neutral terminal, the V-phase output terminal, the W-phase neutral terminal, and the U-phase output terminal of the stator coil 40 are arranged. That is, on the axial end surface of the stator coil 40, the U-phase, V-phase, and W-phase output terminals are arranged on the same area as the U-phase, V-phase, and W-phase neutral terminals; the crossover parts 70 are arranged in a different area than the U-phase, V-phase and W-phase output terminals and the U-phase, V-phase and W-phase neutral terminals.

[0084] The stator core 30 is attached to the above-described stator coil 40 by inserting the tooth portions 30 of the stator core segments 32 into the gaps formed between the stacks of the slot portions 51 of the electric wire 50 from radially outside the stator coil 40. Accordingly, each of the slot portions 51 of the electric wire 50 constituting the stator coil 40 is received in a corresponding slot 31 of the stator core 30. More specifically, for each of the electric wire 50, each adjacent pair of the slot portions 51 is respectively received in a corresponding pair of the slots 31 of the stator core 30, which are circumferentially spaced at a pitch of six slots. Furthermore, each of the turning portions 52 connecting a corresponding pair of the slot portions 51 protrudes from a corresponding axial end surface of the stator core 30.

[0085] The stator 20 described above according to the present embodiment has the following advantages.

[0086] In the present embodiment, the stator 20 includes the hollow cylindrical stator core 30 and the stator coil 40. The stator core 30 has the 48 slots 31 formed in the radially inner surface of the stator core 30 and spaced in the circumferential direction of the stator core 30. The stator coil 40 is composed of the 48 electric wire leads 50 mounted on the stator core 30. Each of the electric wire leads 50 has the first to twelfth slot portions 51A to 51L and the first to eleventh turn portions 52A to 52K. The twelve (i.e., n=12) slot portions 51A to 51L are sequentially accommodated in eight (i.e., p=8, where p is an integer not greater than n) slots 31 of the stator core 30. The eleven (i.e.,(n-1)=11) Turning portions 52A to 52K are alternately arranged on the opposite axial sides of the stator core 30 outside the slots 31 to connect the corresponding adjacent pairs of the first to twelfth slot portions 51A to 51L. Each of the electric wire 50 further includes the pair of connecting portions (or first and second end portions) 53a and 53b. The connecting portion 53a is positioned on the first slot portion 51A side; that is, the connecting portion 53a is closer to the first slot portion 51A than one of the slot portions 51 of the electric wire 50. On the other hand, the connecting portion 53b is positioned on the twelfth slot portion 51L side; That is, the connecting portion 53b is closer to the twelfth slot portion 51L than one of the slot portions 51 of the electric wire 50.Furthermore, the first slot portions 51A of the electric wires 50 are arranged radially outward, and the twelfth slot portions 51L are arranged radially inward in the slots 31 of the stator core 30. The stator coil 40 is a three-phase stator coil consisting of the U-phase, V-phase, and W-phase windings 43. Each of the U-phase, V-phase, and W-phase windings 43 is formed by connecting the 16 electric wires 50. Further, the 16 electric wires 50 include at least a pair of the electric wires 50, one of which has its connecting portion 53a connected to the connecting portion 53b of the other.

[0087] With the above configuration, since each of the phase windings 43 of the stator coil 40 is formed from the 16 electric wires 50, it is possible to shorten the length of each of the electric wires 50. Accordingly, the electric wires 50 can be formed using a small molding machine and can be handled more easily during the manufacture of the stator 20. As a result, it is possible to achieve high productivity and low cost with respect to the stator 20. Furthermore, since the first slot portions 51A of the electric wires 50 are arranged radially outward and the twelfth slot portions 51L are arranged radially inward in the slots 31 of the stator core 30, the connecting portions 53a and 53b of each of the electric wires 50 can be obtained from the radially inner and radially outer peripheries of the stator core 30, respectively.Accordingly, each corresponding pair of connecting portions 53a and 53b of the electrical wires 50 can be sourced from two sufficiently spaced locations, respectively. This improves the flexibility of connecting the electrical wires 50.

[0088] In the present embodiment, the stator coil 40 is obtained by first stacking the electric wire 50 to obtain the band-shaped electric wire assembly 45, and then rolling the assembly 45 into a hollow cylindrical shape.

[0089] That is, the stator coil 40 can be formed without performing a braiding process of the electrical lead wires 50. Therefore, it is possible to reduce both the manufacturing time and the manufacturing cost of the stator coil 40. Furthermore, by shortening the length of the electrical lead wires 50, it is possible to simplify the stacking and stacking and filling processes for forming the stator coil 40.

[0090] In the present embodiment, the number of electrical wires 50 constituting the stator coil 40 is 48; the number of slots 31 formed in the stator core 30 is also 48. That is, the number of electrical parts 50 is equal to that of the slots 31.

[0091] With the above configuration, it is possible to regularly arrange the electrical wires 50 in the stator core 30 such that they are offset from each other in the circumferential direction of the stator core 30 by one slot pitch of the stator core 30. Therefore, it is possible to form the stator coil 40 to have a substantially perfectly hollow cylindrical shape. Furthermore, with the substantially perfectly hollow cylindrical shape of the stator coil 40, it is possible to ensure high performance of the rotating electrical machine.

[0092] In the present embodiment, each of the connecting portions 53b of the electric wire 50 is bent outward in a radial direction of the stator core 30 and connected to a corresponding one of the connecting portions 53a of the electric wire 50.

[0093] With the above configuration of the connecting portions 53b, it is possible to reliably prevent the twelfth slot portions 51L of the electric wires 50, which are arranged radially inward in the slots 31 of the stator core 30, from protruding radially inward due to the springback of the electric wires 50. Therefore, it is possible to reliably prevent the stator coil 40 from interfering with the rotor of the rotating electrical machine, which is arranged radially inward in the stator 20.

[0094] In the present embodiment, each of the connecting portions 53b of the electric wire 50 is configured to include a crossover part 70 that crosses the annular axial end surface of the stator coil 40 from the radially inner side to the radially outer side of the axial end surface.

[0095] With the crossover parts 70 of the connecting portions 53b, it is possible to more reliably prevent the twelfth slot portions 51L of the electric wires 50 from projecting radially inward.

[0096] In the present embodiment, each of the crossover parts 70 of the connecting portions 53b of the electric wires 50 is crank-shaped to include the pair of radially extending end portions 70a and 70b.

[0097] With the above shape, it is possible to facilitate the bending of the connecting portions 53b of the electric wires 50 to form the crossover parts 70 and the welding of the corresponding pairs of the connecting portions 53a and 53b of the electric wires 50. Furthermore, at the connecting portions 53a, it is possible to exert a restraining force in a radially outward direction on the twelfth slot portions 51L via the connecting portions 53b, thereby more reliably preventing the twelfth slot portions 51L from protruding radially inward.

[0098] In the present embodiment, the crossover portions 70 of the connecting portions 53b of the electric wires 50 are arranged on the same axial side of the stator core 30 as the U-phase, V-phase, and W-phase output terminals and the U-phase, V-phase, and W-phase neutral terminals. Furthermore, on the annular axial end surface of the stator coil 40, the crossover portions 70 are arranged at a different angular range of the axial end surface than the U-phase, V-phase, and W-phase neutral terminals. That is, the U-phase, V-phase, and W-phase neutral terminals are arranged in the same angular range.

[0099] With the above arrangement, it is possible to reference the U-phase, V-phase and W-phase neutral terminals together, thereby enabling or facilitating the electrical connection of the stator coil 40.

[0100] Further, in the present embodiment, on the annular axial end surface of the stator coil 40, the U-phase, V-phase, and W-phase output terminals are arranged in the same angular range of the axial end surface as the U-phase, V-phase, and W-phase neutral terminals.

[0101] With the above arrangement, it is possible to put all U-phase, V-phase and W-phase output terminals and U-phase, V-phase and W-phase neutral terminals together, thereby further simplifying the electrical connection of the stator coil 40.

[0102] In the present embodiment, in each of the electric wire 50, the connecting portions 53a and 53b are respectively offset inward in the longitudinal direction Y of the electric wire 50 from the first and twelfth slot portions 51A and 51L by the lengths of the half-turn portions 52M and 52N.

[0103] With the above configuration, the distances between the corresponding pairs of the connecting portions 53a and 53b of the electric wires 50 can be reduced, whereby the resistance of the stator coil 40 and thus the copper loss of the stator 20 can be reduced.

[0104] In the present embodiment, the corresponding pairs of connecting portions 53a and 53b of the electric wires 50 are connected by welding. Accordingly, the corresponding pairs of connecting portions 53a and 53b can be securely connected to each other, thereby ensuring the durability of the stator 20.

[0105] Furthermore, in the present embodiment, the corresponding pairs of connecting portions 53a and 53b of the electric wires 50 are welded radially outside the radially outermost turning portions 52 of the electric wires 50. Accordingly, the insulation sheaths 68 of the turning portions 52 of the electric wires 50 are prevented from being damaged by the heat generated during welding.

[0106] In the present embodiment, each of the turning portions 52 of the electric wire 50 is stepped to include the plurality of shoulder parts 55 and 56 extending parallel to the corresponding axial end surfaces 30a of the stator core 30 from which the turning portion 52 protrudes.

[0107] With the shoulder portions 55 and 56, the protruding height of each of the turning portions 52 from the corresponding axial end surfaces 30a of the stator core 30 can be reduced. As a result, the axial length of the coil end portions 42 of the stator coil 40 can be reduced.

[0108] In the present embodiment, each of the electric wires 50 constituting the stator coil 40 is composed of the electric conductor 67 having a substantially rectangular cross section and the insulation sheath 68 covering the surface of the electric conductor 67.

[0109] With the substantially rectangular cross section, it is possible to densely arrange the slot portions 51 of the electric wires 50 in the slots 31 of the stator core 30 without radial gaps formed therebetween, thereby ensuring high space factors of the electric wires 50 in the slots 31. Furthermore, it is possible to arrange the turn portions 52 of the electric wires 50 without radial gaps formed therebetween, thereby minimizing the radial size of the coil end portions 42 of the stator coil 40.

[0110] In the present embodiment, all the electric wires 50 have the same shape at least between the connecting portions 53a and 53b.

[0111] With the above configuration, it is possible to form all the electric lead wires 50 using the same forming machine, thereby simplifying the forming process of the electric lead wires 50 and reducing the manufacturing cost of the stator coil 40.

[0112] In the present embodiment, the stator coil 40 is configured such that, viewed along the axis O of the stator core 30, each of the electric wire 50 constituting the stator coil 40 extends spirally around the axis O of the stator core 30.

[0113] With the above configuration, it is possible to densely arrange the electric wires 50 without increasing the radial dimension of the stator core 40.

[0114] Fig. 19A illustrates electrical wires 50 according to a first modification of the invention. In this modification, the half-turn portions 52M and 52N are formed to extend outward in the longitudinal direction of the electrical wire 50 from the first and twelfth slot portions 51A and 51L, respectively. Accordingly, the connecting portions 53a and 53b are offset outward in the longitudinal direction from the first and twelfth slot portions 51A and 51L, respectively, by the lengths of the half-turn portions 52M and 52N.

[0115] Fig. 19B illustrates the electrical wires 50 according to a second modification of the invention. In this modification, the half-turn portion 52M is formed to extend outward in the longitudinal direction of the electrical wire 50 from the first slot portion 51A, and the half-turn portion 52N is formed to extend inward in the longitudinal direction from the twelfth slot portion 51L. Accordingly, the connecting portion 53a is offset longitudinally from the first slot portion 51A by the length of the half-turn portion 52N, and the connecting portion 53b is offset inward in the longitudinal direction from the twelfth slot portion 51L by the length of the half-turn portion 52N.

[0116] Fig. 20A illustrates the electrical wires 50 according to a third modification of the invention. In this modification, the half-turn portion 52M is formed to extend inward in the longitudinal direction of the electrical wire 50 from the first slot portion 51A, and the half-turn portion 52N is formed to extend outward in the longitudinal direction from the twelfth slot portion 51L. Accordingly, the connecting portion 53a is offset inward in the longitudinal direction from the first slot portion 51A by the length of the half-turn portion 52M, and the connecting portion 53b is offset outward in the longitudinal direction from the twelfth slot portion 51L by the length of the half-turn portion 52N.

[0117] Fig. 20B illustrates the electric wires 50 according to a fourth modification of the invention. In this modification, both the half-turn portions 52M and 52N are omitted, so that the connecting portions 53a and 53b extend respectively from the first and twelfth slot portions 51A and 51L without being offset therefrom in the longitudinal direction of the electric wires 50.

[0118] Fig. Fig. 21 illustrates the electrical lead wire 50 according to a fifth modification of the invention. In this modification, as shown in Fig. As shown in FIG. 12A, the shoulder portions 56 are omitted from each of the turning portions 52 of the electric wire 50. Accordingly, the portions between the crank-shaped portion 54 and the shoulder portions 55 in each of the turning portions 52 of the electric wire 50 become straight. As a result, the shape of the turning portions 52 of the electric wire 50 is simplified, thereby facilitating the molding of the electric wire 50.

[0119] Fig. 22A to 22B illustrate the electric wires 50 according to a sixth modification of the invention. In this modification, both half-turn portions 52M and 52N are formed straight without being bent as in the Fig. 11A to 11B. With the straight shape of the half-turn sections 52M and 52N, the connecting sections 53a and 53b can be positioned more easily and accurately. Furthermore, it is possible to make only one of the half-turn sections 52M and 52N straight. [Second embodiment]

[0120] Fig. 23 to 24 illustrate a stator 20 according to a second embodiment of the invention. This stator 20 has basically the same configuration as the stator 20 according to the first embodiment; accordingly, only the differences therefrom will be described below.

[0121] As described above, in the first embodiment, the corresponding pairs of the connecting portions 53a (ie, first end portions) and connecting portions 53b (ie, second end portions) of the electric wires 50 are connected via the crossover parts 70 provided in the connecting portions 53b.

[0122] Compared to the present embodiment, the crossover parts 70 are omitted from the connecting portions 53b of the electric wires 50. Instead, the stator 20 is provided with a terminal 80 for connecting the corresponding pairs of the connecting portions 53a and 53b of the electric wires 50.

[0123] More precisely, as in Fig. 25, the connecting portions 53a and 53b of the electrical wires 50 remain unconnected before the assembly of the connection 80 of the stator coil 40 in an angular range E of the annular axial end surface of the stator coil 40; the angular range E is substantially ¾ of the entire angular range of the axial end surface. In addition, with respect to Fig. 26, all the connecting portions 53a and 53b of the electric wires 50 have the same protruding height from the axial end surface 30a of the stator core 30 as the turning portions 52 of the electric wires 50.

[0124] As in the Fig. 27 to 29, the connector 80 is composed of a substrate 81 and a plurality of (e.g., 34 in the present embodiment) electrical conductors 34 embedded in the substrate 81. The substrate 81 is made of an electrically insulating material such as an electrically insulating resin. The substrate 81 has a partial ring shape to cover the angular range E of the annular axial end surface of the stator coil 40. The conductors 82 are formed to have the same crank-like shape as the crossover portions 70 according to the first embodiment. The conductors 82 are equally spaced at predetermined intervals in the circumferential direction of the substrate 81 (or in the circumferential direction of the stator core 30). Further, each of the conductors 82 has a pair of radially extending end portions 82a and 82b.The end portions 82a and 82b are bent respectively in the radial inner and outer peripheries of the substrate 81 so as to protrude from a main surface of the substrate 81 which is opposite to the connecting portions 53a and 53b of the stator coil 40.

[0125] The joint 80 is mounted on the stator coil 40 such that the end portions 82a of the conductors 82 are respectively connected to the connecting portions 53b of the electric wires 50, and the end portions 80b are respectively connected to the connecting portions 53a. Subsequently, the end portions 82a of the conductors 82 are respectively welded to the connecting portions 53b of the electric wires 50 on the radially inner periphery of the stator coil 40; the end portions 82b are respectively welded to the connecting portions 53a of the radially outer periphery of the stator coil 40. As a result, the corresponding pairs of the connecting portions 53a and 53b of the electric wires 50 are connected via the conductors 82 of the joint 80.

[0126] As described above, the electrical connection between the corresponding pairs of connecting portions 53a and 53b of the electrical wires 50 in the present embodiment is established by means of the joint 80. The conductors 82 of the joint 80 perform the same function as the crossover parts 70 of the connecting portions 53b according to the first embodiment.

[0127] By using the connection 80, it is possible to easily and accurately position the conductors 82 corresponding to the connecting portions 53a and 53b of the electric wires 50, thereby improving the assembly efficiency of the stator 20.

[0128] While the above embodiments and modifications of the invention have been particularly shown and described, it is to be understood that further modifications, changes and improvements may be made by those skilled in the art without departing from the scope of the invention.

[0129] For example, in the first embodiment, the connecting portions 53b of the electrical wires 50 are bent radially outward so that they are connected to corresponding connecting portions 53a on the radial output side of the stator coil 40. However, instead of bending the connecting portions 53b, it is also possible to bend the connecting portions 53a radially inward so that they are connected to corresponding connecting portions 53b on the radial inside of the stator coil 40.

[0130] Fig. 30 illustrates the connecting portions 53a and 53b of the electric wires 50 according to a seventh modification of the invention. In this modification, the connecting portions 53a and 53b are bent radially inward or radially outward alternately in the circumferential direction of the stator core 30; the welds 53c between the corresponding pairs of the connecting portions 53a and 53b are formed on the radially inner side or radially outer side of the stator coil 40 alternately in the circumferential direction of the stator core 30.

[0131] Fig.31 illustrates the connecting portions 53a and 53b of the electric wires 50 according to an eighth modification of the invention. In this modification, the connecting portions 53a and 53b are bent to form the welds 53c between the corresponding pairs of the connecting portions 53a and 53b on the radially outer side or the radially middle position of the stator coil 40 alternately in the circumferential direction of the stator core 30.

[0132] With the above configuration of the connecting portions 53a and 53b according to the seventh and eighth modifications, it is possible to increase the distance between each adjacent pair of the welds 53c, thereby improving the electrical insulation therebetween.

[0133] Furthermore, in the first embodiment, the crossover portions 70 are configured to extend substantially along an annular axial end surface of the stator coil 40 from the radially inner side to the radially outer side of the axial end surface. However, the crossover portions 70 may also be configured to extend from the radially inner side to the radially outer side of the axial end surface while maintaining a predetermined distance from the axial end surface of the stator coil 40.

[0134] In the present embodiment, the crossover parts 70 are formed to have a crank-like shape. However, the crossover parts 70 may also be formed to have other shapes, such as a straight shape.

[0135] In the first embodiment, the crossover parts 70 are arranged on the annular axial end surface of the stator coil 40 in a different angular range than the U-phase, V-phase, and W-phase output terminals and the U-phase, V-phase, and W-phase neutral terminals. However, the crossover parts 70 may also be arranged in the same angular range as the U-phase, V-phase, and W-phase output terminals and the U-phase, V-phase, and W-phase neutral terminals.

[0136] In the first embodiment, the corresponding pairs of connecting portions 53a and 53b of the electric wires 50 are connected by welding. Any suitable welding method, such as laser welding, can be used for the welding method.

[0137] Furthermore, the corresponding pairs of the connecting portions 53a and 53b of the electric lead wires 50 may also be connected by other methods such as soldering or using crimp contacts.

[0138] In the first embodiment, after welding the respective pairs of the connecting portions 53a and 53b of the electric wire 50, it is preferable to take an additional measurement to protect the welds formed between the connecting portions 53a and 53b, for example, by covering the welds with respective insulation sheaths or with a one-piece insulation sheath or a one-piece insulation cover.

[0139] In the first embodiment, each of the turning portions 52 of the electrical wires 50 includes the crank-shaped part 54 formed substantially at the center of the turning portion 52 for radially offsetting a corresponding pair of the slot portions 51 connected by the turning portion 52. However, the crank-shaped part 54 is not necessarily formed substantially at the center of the turning portion 52. The crank-shaped part 54 may, for example, be formed near one end of the turning portion 52.

[0140] In the first embodiment, the amount of radial offset created by each of the crank-shaped parts 50 of the turn sections 52 is set equal to the radial thickness of the slot sections 51 of the electrical wires 50. However, the amount of radial offset created by each of the crank-shaped parts 54 may also be set, for example, to 0.5, 1.2, or 2 times the radial thickness of the slot sections 51. In such cases, the difference in radial distance from the axis O of the stator core 30 between each adjacent pair of slot sections 51 connected by corresponding turn sections 52 would be 0.5, 1.5, or 2 times the radial thickness of the slot sections 51, respectively.

[0141] In the first embodiment, n=12, where n is the number of slot portions 51 provided in each of the electric wires 50. However, n may be any integer not less than 4. Furthermore, it is preferable that n be an even number to locate the connecting portions 53a and 53b on the same axial side of the stator core 30.

[0142] In the first embodiment, the radial distances of the first to twelfth slot portions 51A to 51L from the axis O of the stator core 30 for each of the electric wires 50 successively decrease by equal intervals or decrements (i.e., in decrements equal to the radial thickness of the slot portions 51A to 51L). However, each of the electric wires 50 may also be modified so that the radial distances of the first to twelfth slot portions 51A to 51L from the axis O of the stator core 30 successively decrease by different decrements.

[0143] In the first embodiment, the number of slot portions 51 of the electric wires 50 radially stacked in each of the slots 31 of the stator core 30 is set equal to the number of slot portions 51 provided in each of the electric wires 50. However, the number of slot portions 51 of the electric wires 50 radially stacked in each of the slots 31 of the stator core 30 may also be set with a different number of slot portions 51 provided in each of the electric wires 50.

[0144] In the first embodiment, the number of electrical wires 50 forming the stator coil 40 is equal to the number of slots 31 formed in the stator core 30. However, the number of electrical wires 50 forming the stator coil 40 may be different from the number of slots 31 formed in the stator core 30.

[0145] In the first embodiment, the stator coil 40 is formed as a three-phase stator coil consisting of the U-phase, V-phase, and W-phase windings 43. However, the stator coil 40 may also be formed as any other multi-phase coil, for example, a two-phase stator coil.

[0146] Further, each of the U-phase, V-phase, and W-phase windings 43 is formed by connecting 16 electric wires 50. However, each of the U-phase, V-phase, and W-phase windings 43 may also be formed by connecting another plurality of electric wires, for example, two electric wires.

Claims

[1] Stator (20) for a rotating electrical machine, the stator (20) comprising: a hollow cylindrical stator core (30) having a longitudinal axis (o) and a plurality of slots (31) formed in a radial inner surface of the stator core (30) and spaced apart in the circumferential direction of the stator core (30); and a stator coil (40) consisting of a plurality of electrical wires (50) mounted on the stator core (30), where each of the electrical conductor wires (50) has first, second, ..., n-th slot sections (51) and first, second, ..., (n-1)-th turning sections (52), where n is an integer not less than 4, the first to n-th slot sections (51) are sequentially received in p of the slots of the stator core (30), where p is an integer not greater than n, the first to (n-1)th turning sections (52) are arranged alternately on opposite axial sides of the stator core (30) outside the slots (31) to connect corresponding adjacent pairs of the first to nth slot sections (51), each of the electrical conductor wires (50) further comprises first and second end portions (53a, 53b), wherein the first end portion (53a) is closer to the first slot portion (51A) than one of the slot portions (51) of the electrical conductor wire (50), and the second end portion (53b) is closer to the n-th slot portion (51L) than one of the slot portions (51) of the electrical pair, the first slot sections (51) of the electrical conductor wires (50) are arranged radially outward and the n-th slot sections (51) are arranged radially inward in the slots (31) of the stator core (30), for each of the electrical conductor wires (50), the radial distances from the longitudinal axis of the stator core (30) to the first to the n-th slot section (51) of the electrical wire decrease successively in the order from the first slot section (51A) to the n-th slot section (51L), the stator coil (40) is a multi-phase stator coil (40) consisting of a plurality of phase windings (43), each of the phase windings (43) of the stator coil (40) is formed from at least two of the electrical lead wires (50), and the first end portion (53a) of one of the electrical lead wires (50) is connected to the second end portion (53b) of the other electrical lead wire (50). [2] The stator according to claim 1, wherein the stator coil is a hollow cylindrical electric wire assembly formed by rolling up a band-shaped electric wire assembly, and the band-shaped electric wire assembly is formed by stacking the plurality of electric wires. [3] The stator according to claim 1, wherein the number of electric wires forming the stator coil is equal to the number of slots formed in the stator core. [4] The stator according to claim 1, wherein the second end portion of the other electric wire is bent outward in the radial direction of the stator core. [5] The stator according to claim 1, wherein the first end portion of the electrical lead wire is connected to the second end portion of the other electrical lead wire via an electrically conductive intersection member (70) extending to intersect an annular axial end surface of the stator coil from the radially inner side to the radially outer side of the axial end surface. [6] A stator according to claim 5, wherein the intersection member is crank-shaped so as to include a pair of radially extending end portions (70a, 70b). [7] A stator according to claim 5, wherein each of the phase windings of the stator coil has a neutral terminal connected to a neutral point of the stator coil, and on the annular axial end surface of the stator coil, the intersection elements of the phase windings of the stator coil are arranged in different angular ranges of the axial end surface than the neutral terminals of the phase windings. [8] A stator according to claim 7, wherein each of the phase windings of the stator coil further has an output terminal, and on the annular axial end surface of the stator coil, the output terminals of the phase windings of the stator coil are arranged in the same angular range of the axial end surface as the neutral terminals of the phase windings. [9] The stator according to claim 5, wherein the second end portion of the other electric wire is formed to include the intersection member integrated therein. [10] The stator of claim 1, wherein the stator further comprises a joint including a plurality of electrical conductors (67), and the first end portion of the electrical lead wire connects to the second end portion of the other electrical lead wire via a corresponding one of the conductors of the joint. [11] The stator of claim 10, wherein the interconnection further includes a substrate made of an electrically insulating material, the conductors being embedded in the substrate. [12] The stator according to claim 1, wherein in each of the electric wire forming the stator coil, at least one of the first and second end portions of the electric wire is offset inward in the longitudinal direction of the electric wire to the closer one of the first and n-th slot portions of the electric wire. [13] The stator according to claim 1, wherein in each of the phase windings of the stator coil, the first end portion of the electric wire is welded to the second end portion of the other electric wire. [14] The stator according to claim 13, wherein the first end portion of the electric wire and the second end portion of the other electric wire are welded radially outside the radially outermost turning portions of the electric wires. [15] The stator according to claim 1, wherein each of the turning portions of the electric wire is stepped to include a plurality of shoulder parts extending parallel to an axial surface of the stator core from which the turning portion protrudes. [16] The stator according to claim 1, wherein each of the electric wire forming the stator coil further includes a half-turn portion formed between the first end and the first slot portion, and a second half-turn portion formed between the second end and the n-th slot portion of the electric wire, and in each of the electric wire, at least one of the first and second half-turn portions of the electric wire is formed straight. [17] The stator of claim 1, wherein each of the electrical lead wires forming the stator coil consists of an electrical conductor having a substantially rectangular cross-section and an insulating sheath (68) covering the surface of the electrical conductor. [18] The stator according to claim 1, wherein all the electrical wires forming the stator coil have the same shape at least between the first and second end portions. [19] Stator according to claim 1, wherein each of the electrical lead wires extends spirally around the longitudinal axis (0) of the stator core when viewed along this longitudinal axis.

Images