Rotating electric machines

Abstract

This rotating electric machine (1) comprises: an inner rotor (2); a stator core (20) having a plurality of teeth (24); insulators (30) enclosing the teeth (24); coils (40U, 40V, 40W) formed by winding windings (41) around the teeth (24) via the insulators (30); a plurality of bus bars (50N, 50U, 50V, 50W) for electrically connecting the coils (40U, 40V, 40W) to each other; and a holding portion (80) integrally provided at the insulators (30), separating the plurality of bus bars (50N, 50U, 50V, 50W) from each other in the radial direction and holding the plurality of bus bars (50N, 50U, 50V, 50W), and disposed further on the inner side in the radial direction than the stator core (20).

Description

[Technical Field]

[0001] The present invention relates to a rotating electric machine. [Background technology]

[0002] Conventionally, in a stator incorporated in a rotating electric machine such as a motor, coils wound around the teeth of a stator core are sometimes connected to each other via bus bars (see, for example, Patent Document 1). Patent Document 1 discloses a bus ring in which a plurality of ring-shaped conductive bus bars are stacked via insulating spacers, which are insulating resin molded products, and are integrally molded from resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-154084 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described conventional technology, forming a bus ring requires spacers in addition to bus bars, and further requires molding of resin, which may increase the manufacturing costs of the rotating electrical machine.

[0005] The present invention provides a rotating electric machine that can be provided with bus bars that connect coils together while reducing manufacturing costs. [Means for solving the problem]

[0006] A first aspect of the rotating electric machine according to the present invention comprises an inner rotor (2) having a permanent magnet (10), a stator core (20) having a plurality of teeth (24) arranged circumferentially and radially outward of the inner rotor (2), an insulator (30) surrounding the teeth (24), coils (40U, 40V, 40W) formed by winding a winding (41) around the teeth (24) via the insulator (30), a plurality of bus bars (50N, 50U, 50V, 50W) electrically connecting the coils (40U, 40V, 40W) to each other, and a retaining portion (80) integrally formed with the insulator (30), which holds the plurality of bus bars (50N, 50U, 50V, 50W) radially spaced apart from each other and is arranged radially inward of the stator core (20).

[0007] According to this configuration, the holding portion for holding the busbar is integrally provided with the insulator, thereby reducing the number of parts compared to a configuration in which the parts for holding the busbar are provided separately from the insulator. This allows the busbar to be provided while reducing manufacturing costs. Furthermore, since the holding portion is located radially inward of the stator core, the rotating electric machine can be prevented from becoming larger in the radial direction. This allows the rotating electric machine to be made more compact.

[0008] A second aspect of the rotating electric machine according to the present invention is the rotating electric machine of the first aspect, wherein the holding portion (80) may have an insulating wall (82) interposed between the plurality of bus bars (50N, 50U, 50V, 50W).

[0009] With the above configuration, the bus bars can be insulated from each other by the holding portion without using a separate member such as a spacer, etc. This reduces the number of parts and reduces manufacturing costs.

[0010] A third aspect of the rotating electric machine according to the present invention is the rotating electric machine of the first or second aspect, wherein the winding (41) has lead-out portions (42, 43) extending radially inward from the coil (40U, 40V, 40W) and connected to any one of the plurality of bus bars (50N, 50U, 50V, 50W), and the insulator (30) may have slits (37) through which the lead-out portions (42, 43) pass.

[0011] With the above configuration, the lead-out portion can be positioned relative to the holding portion that is integral with the insulator, so that the winding can be easily routed to the bus bar held by the holding portion.

[0012] A fourth aspect of the rotating electric machine according to the present invention is a rotating electric machine according to any one of the first to third aspects, wherein each of the plurality of bus bars (50U, 50V, 50W) has a winding connection portion (52) extending outward along the radial direction and connected to the winding (41), the holding portion (80) has a plurality of holding grooves (83) in which the plurality of bus bars (50U, 50V, 50W) are respectively arranged, and the holding portion (80) may have an abutment portion (85) radially outward of the plurality of holding grooves (83) that abuts against the winding connection portion (52).

[0013] With the above configuration, the abutment portions are positioned radially outward of the portions of the busbar held in the respective retaining grooves. This allows the winding connection portions of the busbars connected to coils of any phase to be positioned by the abutment portions using retaining portions with the same structure. Therefore, it is not necessary to use different insulators with integrated retaining portions depending on the coil phase, and the integrated insulator and retaining portion can be used in common. This prevents an increase in the number of different parts, thereby reducing manufacturing costs.

[0014] A fifth aspect of the rotating electric machine according to the present invention is a rotating electric machine according to any one of the first to fourth aspects, further comprising a casing (105) to which the stator core (20) is fixed, and the retaining portion (80) may be arranged between the inner rotor (2) and the casing (105).

[0015] If the retaining portion were positioned on the opposite side of the inner rotor from the casing, the retaining portion would get in the way, making it difficult to later assemble the inner rotor with the stator core fixed to the casing. By configuring it as described above, the retaining portion is not positioned in the area through which the inner rotor passes during the process of assembling the inner rotor in its designated position. This makes it possible to assemble the inner rotor with the stator core fixed to the casing. Therefore, the simplified manufacturing process can reduce manufacturing costs.

[0016] A sixth aspect of the rotating electric machine according to the present invention is the rotating electric machine of the fifth aspect, wherein the busbars (50U, 50V, 50W) have three-phase line connection portions (53) extending along the axial direction and connected to three-phase lines (60), and the three-phase line connection portions (53) may be fastened to the three-phase lines (60) in the radial direction.

[0017] If the three-phase wire connection portion and the three-phase wires are fastened in the axial direction, the connection portion between the three-phase wire connection portion and the three-phase wires is arranged to protrude further in the axial direction from the three-phase wire connection portion extending along the axial direction. Furthermore, if the three-phase wire connection portion and the three-phase wires are fastened in the circumferential direction, the connection portion between the three-phase wire connection portion and the three-phase wires may be enlarged in the radial or axial direction. This configuration allows the three-phase wire connection portion and the connection portion between the three-phase wires to be arranged in the limited space between the inner rotor and the casing. Furthermore, interference between the three-phase wire connection portion and the connection portion between the three-phase wires and other components, such as the rotating shaft fixed to the inner rotor, can be prevented in the space near the rotation axis. Therefore, the distance between the inner rotor and the casing is prevented from increasing, allowing the rotating electric machine to be made smaller.

[0018] A rotating electric machine of a seventh aspect of the present invention is a rotating electric machine of any one of the first to sixth aspects, wherein the busbars (50U, 50V, 50W) have three-phase line connection portions (53) extending along the axial direction and fastened to terminals (61) of three-phase lines (60), the three-phase line connection portions (53) include engagement portions (54) that engage with the terminals (61), and the engagement portions (54) may abut against the terminals (61) from the rotational direction of fastening members (71).

[0019] With the above configuration, when the fastening member is rotated to fasten the terminal to the three-phase wire connection portion, the terminal is brought into contact with the engagement portion of the three-phase wire connection portion, thereby restricting the terminal from rotating with respect to the three-phase wire connection portion and enabling the three-phase wire connection portion and the terminal to be positioned relative to each other.

[0020] An eighth aspect of the rotating electric machine according to the present invention is the rotating electric machine of the seventh aspect, further comprising a fastening member set (70) having a first fastening member (71) and a second fastening member (72) screwed onto the first fastening member (71) and fastening the three-phase wire connection portion (53) and the terminal (61), wherein one of the first fastening member (71) and the second fastening member (72) abuts against one of the three-phase wire connection portion (53) and the terminal (61) in the rotational direction of the other of the first fastening member (71) and the second fastening member (72).

[0021] With the above configuration, rotation of one of the first fastening member and the second fastening member is restricted by one of the three-phase line connection portion and the terminal, so that the other of the first fastening member and the second fastening member can be screwed into one of the first fastening member and the second fastening member simply by rotating the other of the first fastening member and the second fastening member, thereby simplifying the manufacturing process. [Effects of the Invention]

[0022] According to the above rotating electric machine, it is possible to provide bus bars that connect the coils together while reducing manufacturing costs. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a view of the power unit according to the embodiment as viewed from the axial direction. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Figure 3] FIG. 2 is a view of a rotor and a stator according to the embodiment as viewed from the axial direction. [Figure 4] FIG. 2 is a perspective view showing an insulator and a holding portion according to the embodiment. [Figure 5] FIG. 2 is a perspective view showing a main part of the stator according to the embodiment. [Figure 6] FIG. 2 is a view of the bus bar according to the embodiment as viewed from the axial direction. [Figure 7] FIG. 2 is a perspective view showing bus bars of each phase according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, components having the same or similar functions will be denoted by the same reference numerals. Duplicate descriptions of those components may be omitted.

[0025] Fig. 1 is a view of a power unit according to an embodiment as seen from the axial direction, and Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As shown in FIGS. 1 and 2, the rotating electric machine 1 is an inner rotor type three-phase permanent magnet synchronous motor. The rotating electric machine 1 is a traction motor mounted on a vehicle such as an electric motorcycle. The rotating electric machine 1 includes a cylindrical rotor 2, a stator 3 surrounding the rotor 2, a rotating shaft 4 fixed to the rotor 2, and a motor case 102 accommodating the rotor 2 and the stator 3. In this embodiment, the rotating electric machine 1 is part of a power unit 100. The power unit 100 includes the rotating electric machine 1, a reducer (not shown) that reduces the driving rotation of the rotating electric machine 1 and outputs it, and a power unit case 101 that forms the outer shell of the power unit 100. The power unit case 101 will be described later. The rotor 2, the stator 3, and the rotating shaft 4 are all arranged with a common axis C. In the following description, the direction in which the axis C extends is referred to as the axial direction, the direction perpendicular to the axis C is referred to as the radial direction, and the direction going around the axis C is referred to as the circumferential direction.

[0026] 1, the rotor 2 is an embedded magnet rotor. The rotor 2 is rotatable around an axis C. The rotor 2 includes a permanent magnet 10 and a rotor core 11 that holds the permanent magnet 10.

[0027] The rotor core 11 is formed in a cylindrical shape extending in the axial direction. The rotor core 11 is formed, for example, by laminating a plurality of electromagnetic steel sheets in the axial direction. The rotor core 11 may also be a so-called pressed powder core obtained by compressing and molding metal magnetic powder (soft magnetic powder). The outer periphery of the rotor core 11 holds permanent magnets 10. The outer periphery has a plurality of magnetic pole portions 12. The magnetic pole portions 12 are evenly spaced in the circumferential direction. Each magnetic pole portion 12 has a pair of magnet slots 13 formed therein into which the permanent magnets 10 are inserted. The magnet slots 13 penetrate the rotor core 11 in the axial direction.

[0028] The permanent magnets 10 are rare earth magnets. Examples of rare earth magnets include neodymium magnets, samarium-cobalt magnets, and praseodymium magnets. The permanent magnets 10 are inserted into the magnet slots 13 of the rotor core 11 and fixed to the rotor core 11 with, for example, resin or adhesive. The permanent magnets 10 are magnetized in the radial direction. The permanent magnets 10 have multiple magnetic pole portions 12 arranged such that the magnetization direction alternates circumferentially.

[0029] FIG. 3 is a view of the rotor and the stator of the embodiment as viewed from the axial direction. 3, the stator 3 is a three-phase Y-connected salient pole winding stator. The stator 3 includes a stator core 20, an insulator 30, coils 40U, 40V, and 40W, bus bars 50N, 50U, 50V, and 50W, and a retaining portion 80.

[0030] The stator core 20 is formed by arranging a plurality of split cores 22 (12 in this embodiment) in an annular manner along the circumferential direction. For example, the split cores 22 are formed by stacking a plurality of T-shaped electromagnetic steel sheets punched by a press. The split cores 22 include back yoke pieces 23 extending along the circumferential direction and teeth 24 extending radially inward from the back yoke pieces 23. The back yoke pieces 23 form the annular back yoke 21 of the stator core 20 by connecting the split cores 22 in the circumferential direction. The teeth 24 form slots 26 between adjacent teeth 24 by connecting the split cores 22 in the circumferential direction. The radially inner ends of the teeth 24 face the magnetic pole portions 12 of the rotor 2 (see FIG. 1). The circumferentially connected split cores 22 are fixed to each other by a stator ring 28 (see FIG. 1).

[0031] FIG. 4 is a perspective view showing the insulator and the holding portion of the embodiment. As shown in Figures 3 and 4, the insulators 30 are attached to each split core 22 so as to surround the teeth 24. The insulators 30 are made of an electrically insulating material such as resin. The insulators 30 are divided into two parts: a first insulator 30A and a second insulator 30B. The first insulator 30A and the second insulator 30B are divided at the axial middle of the teeth 24. The middle part may be located between one axial end and the other axial end of the teeth 24. The first insulator 30A covers the end faces of the teeth 24 facing in a first axial direction and the first axial portions of both circumferential side faces. The second insulator 30B covers the end faces of the teeth 24 facing in a second axial direction and the second axial portions of both circumferential side faces.

[0032] The insulator 30 includes an inner peripheral wall 31 that follows the outer peripheral surfaces of the teeth 24, an inner flange 32 that protrudes from a radially inner edge of the inner peripheral wall 31, and an outer flange 33 that protrudes from a radially outer edge of the inner peripheral wall 31. The inner peripheral wall 31, inner flange 32, and outer flange 33 are formed on both the first insulator 30A and the second insulator 30B. The inner peripheral wall 31, inner flange 32, and outer flange 33 are arranged to surround the teeth 24 over the entire circumference except for the division positions of the first insulator 30A and the second insulator 30B. The inner peripheral wall 31, inner flange 32, and outer flange 33 are integrally formed on each of the first insulator 30A and the second insulator 30B. Between the inner flange 32 and the outer flange 33, a winding groove 34 is formed in which the coils 40U, 40V, 40W wound around the inner circumferential wall 31 are arranged.

[0033] As shown in FIG. 4, the first insulator 30A is formed with a turn locking portion 36 and a pair of slits 37. The turn locking portion 36 is a protrusion that protrudes from the outer flange 33. The turn locking portion 36 protrudes in the first direction from the edge of the outer flange 33 in the first axial direction. The slits 37 are formed in the inner flange 32. The slits 37 are formed in the edge of the inner flange 32 in the first axial direction. The slits 37 are formed at intervals in the circumferential direction.

[0034] As shown in FIG. 3 , coils 40U, 40V, and 40W are formed by winding wire 41 around teeth 24 via insulator 30. Coils 40U, 40V, and 40W are wound around inner circumferential wall 31 of insulator 30 and positioned between inner flange 32 and outer flange 33. Coils 40U, 40V, and 40W are U-phase coil 40U, V-phase coil 40V, and W-phase coil 40W, which are arranged with a phase difference of 120° from each other in the circumferential direction. U-phase coil 40U, V-phase coil 40V, and W-phase coil 40W are arranged in this order in the circumferential direction. One end of each of coils 40U, 40V, and 40W is electrically connected in common to the neutral point of the Y-connection. The other end of each of coils 40U, 40V, and 40W is electrically connected in common to the electric wire of each phase of three-phase line 60, which will be described later for each phase.

[0035] FIG. 5 is a perspective view showing a main part of the stator of the embodiment. As shown in FIG. 5 , the winding 41 includes a pair of lead-out portions 42, 43 extending radially inward from the coils 40U, 40V, and 40W. The pair of lead-out portions 42, 43 includes a first lead-out portion 42 extending from the winding end of the coils 40U, 40V, and 40W toward the first end 41a of the winding 41, and a second lead-out portion 43 extending from the second end 41b of the winding 41 toward the winding start of the coils 40U, 40V, and 40W. The first lead-out portion 42 and the second lead-out portion 43 extend in the first axial direction from the winding groove 34. The first lead-out portion 42 passes through one slit 37 of the first insulator 30A. The portion of the first lead-out portion 42 closer to the coils 40U, 40V, and 40W than the slit 37 is wound around the turn locking portion 36 of the first insulator 30A for one turn. The second lead-out portion 43 passes through the other slit 37 of the first insulator 30A.

[0036] FIG. 6 is a view of the bus bar according to the embodiment as viewed from the axial direction. As shown in FIGS. 3 and 6 , busbars 50N, 50U, 50V, and 50W electrically connect coils 40U, 40V, and 40W to one another. Busbars 50N, 50U, 50V, and 50W include a neutral busbar 50N, a U-phase busbar 50U, a V-phase busbar 50V, and a W-phase busbar 50W. The neutral busbar 50N is connected to first ends 41a of windings 41 forming coils 40U, 40V, and 40W. The neutral busbars 50N are arranged in the circumferential direction so that one is connected to each of the windings 41 of the U-phase coil 40U, the V-phase coil 40V, and the W-phase coil 40W, which are arranged consecutively in the circumferential direction. In this embodiment, four neutral busbars 50N are provided for each phase, since four coils 40U, 40V, and 40W are provided for each phase. U-phase busbar 50U is connected to second ends 41b of all of the windings 41 forming U-phase coil 40U. V-phase busbar 50V is connected to second ends 41b of all of the windings 41 forming V-phase coil 40V. W-phase busbar 50W is connected to second ends 41b of all of the windings 41 forming W-phase coil 40W. These busbars 50N, 50U, 50V, and 50W are arranged inside insulators 30 arranged in a ring shape when viewed from the axial direction. Busbars 50N, 50U, 50V, and 50W are formed from metal plates. Busbars 50N, 50U, 50V, and 50W each include a winding connection portion 52 connected to windings 41 and a connection portion 51 connecting winding connection portions 52.

[0037] FIG. 7 is a perspective view showing the bus bars of each phase according to the embodiment. As shown in FIGS. 6 and 7 , the connecting portions 51 have a radial thickness and extend at a substantially constant width in the circumferential direction. The connecting portions 51 of each neutral point busbar 50N are arranged at equal intervals in the circumferential direction. The connecting portions 51 of the neutral point busbar 50N, U-phase busbar 50U, V-phase busbar 50V, and W-phase busbar 50W are arranged at predetermined axial positions with radial intervals. In this embodiment, the connecting portions 51 of the W-phase busbar 50W, V-phase busbar 50V, U-phase busbar 50U, and neutral point busbar 50N are arranged radially outward in this order. The connecting portions 51 of the neutral point busbar 50N, U-phase busbar 50U, V-phase busbar 50V, and W-phase busbar 50W have radii of curvature corresponding to their radial positions so as not to intersect with each other.

[0038] As shown in FIGS. 5 to 7 , the winding connection portions 52 are connected to the windings 41. The winding connection portions 52 extend radially outward from the coupling portions 51 when viewed in the axial direction. The winding connection portions 52 are formed integrally with the coupling portions 51. In this embodiment, the neutral point bus bar 50N is connected to each of the windings 41 of the coils 40U, 40V, and 40W of each phase, one by one, and therefore, three winding connection portions 52 extend from the coupling portions 51 in the neutral point bus bar 50N. In this embodiment, four coils 40U, 40V, and 40W are provided for each phase, and therefore, four winding connection portions 52 extend from the coupling portions 51 in the bus bars 50U, 50V, and 50W of each phase.

[0039] As shown in FIG. 5 , the winding connection portions 52 extend from the coupling portions 51 outward in the axial direction (first direction), then bend radially outward, and continue extending radially outward. The radially outer ends of the winding connection portions 52 are located radially outward of a plurality of retaining grooves 83 (described later) and are close to the inner flange 32 of the insulator 30. The ends of the winding connection portions 52 are folded back axially outward to sandwich the winding 41. The winding connection portions 52 of the neutral busbar 50N sandwich the first end 41a of the winding 41. The winding connection portions 52 of the busbars 50U, 50V, and 50W of each phase sandwich the second end 41b of the winding 41. As a result, the neutral busbar 50N electrically connects the U-phase coil 40U, the V-phase coil 40V, and the W-phase coil 40W, which are arranged continuously in the circumferential direction. Furthermore, bus bars 50U, 50V, 50W of each phase electrically connect coils 40U, 40V, 40W of the same phase to each other.

[0040] As shown in FIG. 7 , each of bus bars 50U, 50V, and 50W of each phase further includes a three-phase wire connection portion 53 extending from connecting portion 51. Three-phase wire connection portion 53 extends outward in the axial direction from a middle portion of connecting portion 51. Three-phase wire connection portion 53 is integrally formed with connecting portion 51. Three-phase wire connection portion 53 as a whole has a radial thickness. Three-phase wire connection portion 53 includes a through hole 53h. Through hole 53h extends radially through the axially outer tip of three-phase wire connection portion 53. Shanks of bolts 71 that fasten terminals 61 of three-phase wires 60 are inserted through through hole 53h. Three-phase wire connection portion 53 includes an engagement portion 54 that engages with terminals 61 of three-phase wires 60. Engagement portion 54 protrudes circumferentially. Specifically, engagement portions 54 of U-phase busbar 50U and W-phase busbar 50W protrude clockwise when viewed from the axial direction in which three-phase line connection portion 53 extends (first direction). Engagement portion 54 of V-phase busbar 50V protrudes counterclockwise when viewed from the axial direction in which three-phase line connection portion 53 extends. Three-phase line connection portions 53 of U-phase busbar U, V-phase busbar 50V, and W-phase busbar 50W are arranged circumferentially offset from one another.

[0041] Terminals 61 of the three-phase wire 60 are connected to the three-phase wire connection portion 53. A terminal 61 of the three-phase wire is provided for each phase. In this embodiment, the terminals 61 are formed to have the same shape. The terminals 61 are formed of metal. The terminals 61 include a fastening portion 62 fastened to the three-phase wire connection portion 53 and a crimping portion 65 mechanically and electrically connected to the fastening portion 62 and coupled to the tip of the electric wire of the three-phase wire 60. The fastening portion 62 includes a base portion 63 overlapping the tip portion of the three-phase wire connection portion 53 and a pair of side portions 64 extending in the same direction from the base portion 63. The base portion 63 overlaps the tip portion of the three-phase wire connection portion 53 from the radial outside. The base portion 63 is formed with a through hole (not shown) concentric with the through hole 53h penetrating the three-phase wire connection portion 53. The pair of side portions 64 extend from both circumferential edges of the base portion 63. The pair of side portions 64 extend toward the axis C and are inclined at approximately 90° relative to the base portion 63. The pair of side portions 64 are arranged to sandwich the tip end of the three-phase wire connection portion 53 from the outside in the circumferential direction. One of the pair of side portions 64 abuts against the engaging portion 54 of the three-phase wire connection portion 53 in the clockwise direction around the through hole 53h when viewed from the outside in the radial direction. A crimping portion 65 is connected to the other of the pair of side portions 64. By being coupled to the crimping portion 65, the electric wires of the three-phase wire 60 extend to the opposite side of the engaging portion 54, centered around the tip end of the three-phase wire connection portion 53.

[0042] The three-phase line connection portion 53 and the terminal 61 of the three-phase line 60 are radially fastened by a fastening member set 70. The fastening member set 70 includes a bolt 71 (first fastening member) and a nut 72 (second fastening member) screwed onto the bolt 71. The bolt 71 is inserted from the radial outside into the through hole 53h of the three-phase line connection portion 53 and the through hole of the terminal 61. The nut 72 is a square nut. The nut 72 is screwed onto the shaft of the bolt 71 with the base 63 of the terminal 61 and the three-phase line connection portion 53 sandwiched between the head of the bolt 71 and the nut 72. The nut 72 abuts against the pair of side portions 64 of the terminal 61 in a clockwise direction around the through hole 53h as viewed from the radial outside. Note that the clockwise direction around the through hole 53h as viewed from the radial outside is the rotation direction of the bolt 71 when screwed in.

[0043] As shown in Figures 4 and 5, a holding portion 80 is provided for each of the coils 40U, 40V, and 40W. The holding portion 80 is integrally formed with the first insulator 30A, and is thereby provided integrally with the first insulator 30A. The holding portion 80 is disposed in a first axial direction relative to the rotor 2 and radially inward of the stator core 20. The multiple holding portions 80 are arranged in an annular shape along the circumferential direction. The holding portions 80 hold the connecting portions 51 of the multiple bus bars 50N, 50U, 50V, and 50W at radially spaced-apart intervals from each other.

[0044] The retaining portion 80 includes a bottom portion 81 extending radially inward from the inner flange 32 of the insulator 30, and an insulating wall 82 rising from the bottom portion 81 toward the axially outer side (first direction). The bottom portion 81 extends along the end face of the rotor core 11 in the first axial direction. The bottom portion 81 extends radially inward from the inner flange 32 while narrowing its circumferential width when viewed from the axial direction. A plurality of insulating walls 82 are formed for each retaining portion 80. In the present embodiment, five insulating walls 82 are formed for each retaining portion 80. The insulating walls 82 extend in an arc shape along the circumferential direction and are spaced apart from one another in the radial direction. Retaining grooves 83 are formed between adjacent insulating walls 82 in the radial direction, and the connecting portions 51 of the busbars 50N, 50U, 50V, and 50W are disposed therein. The retaining grooves 83 are open in the first axial direction and extend in an arc shape along the circumferential direction. Since all the retaining portions 80 are arranged in an annular shape, each retaining groove 83 extends in an annular shape as a whole. In this embodiment, four retaining grooves 83 are formed along the radial direction. The three retaining grooves 83 located on the radially inner side of the four retaining grooves 83 are provided with the connecting portions 51 of the busbars 50U, 50V, and 50W of each phase. The retaining groove 83 located on the radially outermost side of the four retaining grooves 83 is provided with the connecting portion 51 of the neutral busbar 50N. As a result, the insulating walls 82 are interposed between the multiple busbars 50N, 50U, 50V, and 50W. In the following description, the multiple insulating walls 82 are referred to as the first insulating wall, the second insulating wall, the third insulating wall, the fourth insulating wall, and the fifth insulating wall, in order from the insulating wall 82 located on the radially innermost side to the radially outermost side.

[0045] The fourth insulating wall 82 is formed higher than the second insulating wall 82 and the third insulating wall 82 relative to the bottom 81. Specifically, the edge of the fourth insulating wall 82 in the first axial direction is positioned further in the first axial direction than the edges of the second insulating wall 82 and the third insulating wall 82 in the first axial direction. The edge of the fourth insulating wall 82 in the first axial direction is in contact with the winding connection portion 52 in the first axial direction.

[0046] The holding portion 80 includes a first abutment portion 85 (abutment portion) that abuts against the winding connection portion 52 of the busbars 50U, 50V, and 50W of each phase, and a second abutment portion 86 that abuts against the winding connection portion 52 of the neutral busbar 50N. The first abutment portion 85 protrudes in the axial direction from an edge of the fourth insulating wall 82 in a first axial direction. The first abutment portion 85 contacts the winding connection portion 52 of the busbars 50U, 50V, and 50W of each phase from one side in the circumferential direction. As a result, the first abutment portion 85 positions the winding connection portion 52 of the busbars 50U, 50V, and 50W of each phase in the circumferential direction. The second abutment portion 86 protrudes in the axial direction from an edge of the fifth insulating wall 82 in the first axial direction. The second abutment portion 86 is provided offset in one circumferential direction with respect to the first abutment portion 85. The second contact portion 86 contacts the winding connection portion 52 of the neutral point bus bar 50N from one side in the circumferential direction, thereby positioning the winding connection portion 52 of the neutral point bus bar 50N in the circumferential direction.

[0047] A through hole 87 is formed in the holding portion 80. The through hole 87 is formed between the fifth insulating wall 82 and the inner flange 32. The through hole 87 penetrates the holding portion 80 in the axial direction. A pair of through holes 87 are formed in each holding portion 80, spaced apart in the circumferential direction. The through holes 87 overlap the tip end of the winding connection portion 52 when viewed in the axial direction. Specifically, one of the pair of through holes 87 overlaps the connection portion between the winding connection portion 52 of the neutral bus bar 50N and the first end 41a of the winding 41 when viewed in the axial direction. The other of the pair of through holes 87 overlaps the connection portion between the winding connection portion 52 of the neutral bus bar 50N and the second end 41b of the winding 41 when viewed in the axial direction.

[0048] As shown in FIG. 2 , the power unit case includes the motor case 102 and the reducer case 103 that houses the reducer. The motor case 102 and the reducer case 103 are aligned in the axial direction. A rotating shaft 4 fixed to the rotor 2 penetrates a partition wall 104 that separates the internal space of the motor case 102 from the internal space of the reducer case 103. The motor case 102 includes a case main body 105 (casing) that opens on the opposite side of the reducer case 103 in the axial direction. The outer periphery of the stator core 20 is fastened and fixed to the case main body 105 from the opposite side of the reducer case 103. The rotor 2 and the stator 3 are arranged such that the holding portion 80 is located between the case main body 105 and the rotor 2. That is, the holding portion 80 and the bus bars 50N, 50U, 50V, and 50W are arranged between the rotor 2 and the reducer case 103 in the axial direction. The opening of the case main body 105 is closed by a cover (not shown).

[0049] As described above, the rotating electric machine 1 of this embodiment includes a plurality of bus bars 50N, 50U, 50V, and 50W that electrically connect the coils 40U, 40V, and 40W to one another, and a retaining portion 80 that is integrally formed with the insulator 30, holds the plurality of bus bars 50N, 50U, 50V, and 50W while spaced apart radially from one another, and is disposed radially inward of the stator core 20. With this configuration, the retaining portion 80 that holds the bus bars 50N, 50U, 50V, and 50W is integrally formed with the insulator 30, thereby reducing the number of components compared to a configuration in which components for holding the bus bars are provided separately from the insulator. This allows the bus bars 50N, 50U, 50V, and 50W to be provided while reducing manufacturing costs. Furthermore, the retaining portion 80 is disposed radially inward of the stator core 20, thereby preventing the rotating electric machine 1 from becoming too large in the radial direction. This allows the rotating electric machine 1 to be made smaller.

[0050] The holding portion 80 has insulating walls 82 interposed between the bus bars 50N, 50U, 50V, and 50W. With this configuration, the bus bars 50N, 50U, 50V, and 50W can be insulated from each other by the holding portion without using separate members such as spacers. This reduces the number of parts and reduces manufacturing costs.

[0051] Winding 41 has lead-out portions 42 and 43 that extend radially inward from coils 40U, 40V, and 40W and are connected to one of multiple bus bars 50N, 50U, 50V, and 50W. Insulator 30 is formed with slits 37 through which lead-out portions 42 and 43 pass. With this configuration, lead-out portions 42 and 43 of winding 41 can be positioned with respect to holding portion 80 that is integral with insulator 30, and therefore winding 41 can be easily routed to bus bars 50N, 50U, 50V, and 50W held by holding portion 80.

[0052] Each of the bus bars 50U, 50V, and 50W has a winding connection portion 52 that extends radially outward and is connected to the winding 41. A plurality of holding grooves 83 are formed in the holding portion 80, in which the bus bars 50U, 50V, and 50W are respectively disposed. The holding portion 80 has a first abutment portion 85 that abuts the winding connection portion 52 radially outward from the holding grooves 83. With this configuration, the first abutment portion 85 is disposed radially outward from the coupling portions 51 of the bus bars 50U, 50V, and 50W held in each of the holding grooves 83. As a result, the winding connection portions 52 of the bus bars 50U, 50V, and 50W that are connected to the coils 40U, 40V, and 40W of any phase can be positioned by the abutment portion 85 using the holding portion 80 having the same structure. Therefore, it is not necessary to use different insulators 30 integrated with holding portions 80 depending on the phase of the coils 40U, 40V, and 40W, and the parts integrated with the insulators 30 and holding portions 80 can be standardized. This prevents an increase in the number of different parts, thereby reducing manufacturing costs.

[0053] The holding portion 80 is disposed between the rotor 2 and the case body 105 of the motor case 102. If the holding portion were disposed on the opposite side of the rotor 2 from the case body 105, the holding portion would get in the way, making it difficult to later assemble the rotor 2 with the stator core fixed to the case body 105. According to this embodiment, the holding portion 80 is not disposed in an area through which the rotor 2 passes during the process of assembling the rotor 2 in a predetermined position. This makes it possible to assemble the rotor 2 with the stator core 20 fixed to the case body 105. Therefore, the manufacturing process can be simplified, thereby reducing manufacturing costs.

[0054] Each of the bus bars 50U, 50V, and 50W has a three-phase wire connection portion 53 extending axially and connected to the three-phase wire 60. The three-phase wire 60 is fastened radially to the three-phase wire connection portion 53. If the three-phase wire connection portion and the three-phase wire are fastened axially, the connection portion between the three-phase wire connection portion and the three-phase wire is arranged to protrude axially from the three-phase wire connection portion extending axially. Furthermore, if the three-phase wire connection portion and the three-phase wire are fastened circumferentially, the connection portion between the three-phase wire connection portion and the three-phase wire can be enlarged radially or axially. According to this embodiment, the connection portion between the three-phase wire connection portion 53 and the three-phase wire 60 can be disposed in the limited space between the rotor 2 and the case body 105. Furthermore, interference between the connection portion between the three-phase wire connection portion 53 and the three-phase wire 60 and other components, such as the rotating shaft 4 fixed to the rotor 2, can be prevented in the space near the axis C. Therefore, the increase in the distance between the rotor 2 and the case body 105 can be suppressed, and the rotating electrical machine 1 can be made smaller.

[0055] Three-phase wire 60 has terminal 61 fastened to three-phase wire connection portion 53. Three-phase wire connection portion 53 has engagement portion 54 that engages with terminal 61. Terminal 61 abuts against engagement portion 54 in the rotation direction of bolt 71. With this configuration, when bolt 71 is rotated to fasten terminal 61 to three-phase wire connection portion 53, terminal 61 abuts against engagement portion 54 of three-phase wire connection portion 53, thereby restricting co-rotation of terminal 61 with three-phase wire connection portion 53 and enabling three-phase wire connection portion 53 and terminal 61 to be positioned relative to each other.

[0056] Nut 72, which fastens three-phase line connection portion 53 and terminal 61, abuts against terminal 61 in the rotation direction of bolt 71. With this configuration, the rotation of nut 72 is restricted by terminal 61, so that bolt 71 can be screwed into nut 72 simply by rotating bolt 71. This simplifies the manufacturing process.

[0057] The present invention is not limited to the above-described embodiment explained with reference to the drawings, and various modifications are possible within the technical scope of the present invention. For example, in the above embodiment, the rotating electric machine 1 is a three-phase permanent magnet synchronous motor with an embedded magnet inner rotor, but the scope of application of the present invention is not limited to this. For example, the rotating electric machine may be a motor with a surface magnet inner rotor in which magnets are attached to the outer circumferential surface of the rotor core. Furthermore, the present invention is also applicable to motors other than three-phase permanent magnet synchronous motors, such as three-phase AC motors and brushless DC motors, which have multiple bus bars that electrically connect coils together, and generators with a configuration similar to these motors.

[0058] In the above embodiment, the arrangement of the neutral bus bar 50N and the bus bars 50U, 50V, and 50W of each phase in the holding portion is not particularly limited. For example, the connecting portion of the neutral bus bar may be arranged radially inward of the connecting portions of the bus bars of each phase.

[0059] In the above embodiment, at the connection between the busbars 50U, 50V, and 50W and the three-phase wires 60, the terminals 61 are placed radially outside the three-phase wire connection portions 53, and then the bolts 71 are screwed from the radial outside. The side portions 64 of the terminals 61 are abutted against the engagement portions 54 of the three-phase wire connection portions 53 in the direction of rotation when the bolts 71 are screwed, thereby restricting the rotation of the terminals 61. However, the structure of the connection between the busbars and the three-phase wires is not particularly limited. For example, the terminals may be placed radially inside the three-phase wire connection portions. Even in this case, it is desirable to restrict the rotation of components that may rotate together when fastened by engaging the three-phase wire connection portions and the terminals, as in this embodiment. Alternatively, the positions of the bolts 71 and the nuts 72 may be reversed, so that the heads of the bolts 71 abut against the pair of side portions 64 of the terminals 61 in the direction of rotation when the nuts 72 are screwed.

[0060] In the above embodiment, the first contact portions 85 that come into contact with the winding connection portions 52 of the bus bars 50U, 50V, and 50W of each phase are formed on the fourth insulating wall 82, but the present invention is not limited to this configuration. The first contact portions may be formed on the fifth insulating wall.

[0061] In addition, the components in the above-described embodiments can be replaced with well-known components as appropriate, without departing from the spirit of the present invention. [Explanation of symbols]

[0062] 1 Rotating electric machine 2 rotor (inner rotor) 10 Permanent Magnets 20 stator core 24 Teeth 30 insulator 37 Slit 40U, 40V, 40W coil 41 Windings 42 1st drawer section (drawer section) 43 2nd drawer section (drawer section) 50N Neutral busbar (busbar) 50U U-phase busbar (busbar) 50V V-phase busbar (busbar) 50W W-phase busbar (busbar) 52 Winding connection 53 Three-phase wire connection 54 Engagement part 60 Three phase line 61 terminals 70 Fastening member set 71 Bolt (fastening member, first fastening member) 72 Nut (second fastening member) 80 Holding part 82 Insulating Wall 83 Retaining groove 85 1st contact part (contact part) 105 Case body (casing)

Claims

1. an inner rotor (2) having permanent magnets (10); a stator core (20) having a plurality of teeth (24) along a circumferential direction and disposed radially outside the inner rotor (2); an insulator (30) surrounding the teeth (24); a coil (40U, 40V, 40W) formed by winding a winding (41) around the teeth (24) via the insulator (30); a plurality of bus bars (50N, 50U, 50V, 50W) formed separately from the coils (40U, 40V, 40W) and electrically connecting the coils (40U, 40V, 40W) to each other; a retaining portion (80) that is integrally formed with the insulator (30) and thus is provided integrally therewith, extends in an annular shape as a whole, holds the plurality of bus bars (50N, 50U, 50V, 50W) spaced apart from one another in the radial direction, and has a plurality of retaining grooves (83) that open in an axial direction relative to the inner rotor (2) and can accommodate the bus bars (50N, 50U, 50V, 50W) from the axial direction, and is arranged radially inward of the stator core (20) on one side of the axial direction relative to the inner rotor (2); Equipped with Each of the plurality of bus bars (50N, 50U, 50V, 50W) has a connecting portion (51) extending with a substantially constant width along a circumferential direction, and a winding connection portion (52) extending outward along a radial direction from the connecting portion (51) and connected to an end of the winding (41), the plurality of bus bars (50N, 50U, 50V, 50W) include a U-phase bus bar (50U), a V-phase bus bar (50V), and a W-phase bus bar (50W), the retaining portion (80) has a contact portion (85) that protrudes in the axial direction radially outward from retaining grooves (83) among the plurality of retaining grooves (83) in which the U-phase bus bar (50U), the V-phase bus bar (50V), and the W-phase bus bar (50W) are respectively accommodated, and that comes into contact with the winding connection portion (52) of any of the U-phase bus bar (50U), the V-phase bus bar (50V), and the W-phase bus bar (50W) from one side in the circumferential direction. Rotating electric motor.

2. The holding portion (80) has insulating walls (82) interposed between the plurality of bus bars (50N, 50U, 50V, 50W). The rotating electric machine according to claim 1 .

3. the winding (41) includes lead-out portions (42, 43) extending radially inward from the coil (40U, 40V, 40W) and connected to any one of the plurality of bus bars (50N, 50U, 50V, 50W); The insulator (30) has a slit (37) through which the lead-out portions (42, 43) pass. The rotating electric machine according to claim 1 or 2.

4. The stator core (20) is fixed to a casing (105). The holding portion (80) is disposed between the inner rotor (2) and the casing (105) in the axial direction. The rotating electric machine according to any one of claims 1 to 3.

5. The bus bar (50U, 50V, 50W) has a three-phase line connection portion (53) extending along the axial direction and connected to a three-phase line (60), The three-phase line connection portion (53) is fastened to the three-phase line (60) in the radial direction. The rotating electric machine according to claim 4.

6. The plurality of bus bars (50N, 50U, 50V, 50W) includes a neutral bus bar (50N), a radially outer tip end of the winding connection portion (52) is located radially outward of the retaining grooves (83) that accommodate the U-phase bus bar (50U), the V-phase bus bar (50V), the W-phase bus bar (50W), and the neutral point bus bar (50N), respectively; The rotating electric machine according to any one of claims 1 to 5.

7. The plurality of bus bars (50N, 50U, 50V, 50W) includes a neutral bus bar (50N), The holding portion (80) has a second abutment portion (86) that protrudes in the axial direction radially outward of a holding groove (83) among the plurality of holding grooves (83) in which the neutral point bus bar (50N) is housed, and that comes into contact with the winding connection portion (52) of the neutral point bus bar (50N) from one side in the circumferential direction. The rotating electric machine according to any one of claims 1 to 6.

8. An inner rotor (2) having a permanent magnet (10), a stator core (20) having a plurality of teeth (24) along a circumferential direction and disposed radially outside the inner rotor (2); an insulator (30) surrounding the teeth (24); a coil (40U, 40V, 40W) formed by winding a winding (41) around the teeth (24) via the insulator (30); a plurality of bus bars (50N, 50U, 50V, 50W) that electrically connect the coils (40U, 40V, 40W) to each other; a retaining portion (80) that is integrally formed with the insulator (30) and holds the plurality of bus bars (50N, 50U, 50V, 50W) spaced apart from one another in the radial direction, and that is disposed radially inward of the stator core (20) on one side of the axial direction relative to the inner rotor (2); Equipped with The busbar (50U, 50V, 50W) has a three-phase line connection portion (53) extending along the axial direction and fastened to a terminal (61) of a three-phase line (60) by a fastening member (71), The three-phase wire connection portion (53) includes an engagement portion (54) that engages with the terminal (61), The engaging portion (54) abuts against the terminal (61) in the rotation direction when the fastening member (71) is fastened, thereby restricting the co-rotation of the terminal (61). Rotating electric motor.

9. a fastening member set (70) having a first fastening member (71) and a second fastening member (72) screwed to the first fastening member (71), for fastening the three-phase line connection portion (53) and the terminal (61); One of the first fastening member (71) and the second fastening member (72) abuts against the terminal (61) in the rotation direction when the other of the first fastening member (71) and the second fastening member (72) is fastened, thereby restricting rotation of the first fastening member (71) and the second fastening member (72) relative to the other. The rotating electric machine according to claim 8.

10. An inner rotor (2) having a permanent magnet (10), a stator core (20) having a plurality of teeth (24) along a circumferential direction and disposed radially outside the inner rotor (2); an insulator (30) surrounding the teeth (24); a coil (40U, 40V, 40W) formed by winding a winding (41) around the teeth (24) via the insulator (30); a plurality of bus bars (50N, 50U, 50V, 50W) formed separately from the coils (40U, 40V, 40W) and electrically connecting the coils (40U, 40V, 40W) to each other; a retaining portion (80) that is integrally formed with the insulator (30) and that holds the plurality of bus bars (50N, 50U, 50V, 50W) spaced apart from one another in the radial direction, and that has a plurality of retaining grooves (83) that open in an axial direction relative to the inner rotor (2) and can accommodate the bus bars (50U, 50V, 50W) from the axial direction, and that is arranged radially inward of the stator core (20) on one side of the axial direction relative to the inner rotor (2); Equipped with The busbar (50U, 50V, 50W) has a three-phase line connection portion (53) extending along the axial direction and fastened to a terminal (61) of a three-phase line (60) by a fastening member set (70), The fastening member set (70) includes a first fastening member (71) and a second fastening member (72) that is threadedly attached to the first fastening member (71), One of the first fastening member (71) and the second fastening member (72) abuts against the terminal (61) in the rotation direction when the other of the first fastening member (71) and the second fastening member (72) is fastened, thereby restricting rotation of the first fastening member (71) and the second fastening member (72) relative to the other. Rotating electric motor.

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