Electric motor

Abstract

To provide an electric motor capable of reducing a filling amount of an adhesive agent for fixing a neighbor of a terminal line part of a coil, and reducing an assembling operation time.SOLUTION: An electric motor comprises: a stator; and a rotor. A plurality of coils 33 of the stator is wound to each of teeth of a stator core 34. A bus bar unit is arranged to one end side of a shaft direction of the stator core. The bus bar unit includes a plurality of bus bar terminals 51Ub, 51Vb, and 51Wb that is arranged over a winding part of each coil adjacent to a peripheral direction. In each bus bar terminal, a start line connection part 54s to which a start line part 33s of one adjacent coil is connected and an end line connection part 54e to which an end line part 33e of the other coil is connected, are provided, respectively. A filling open 65 for filling an adjacent agent is provided to between the start line connection part and the end line connection part of each bus bar terminal in the winding part of the adjacent coil of the end line part.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to an electric motor used as a drive source for a vehicle, etc. [Background technology]

[0002] A known electric motor used as a drive source for a vehicle, etc., is equipped with an annular stator and a rotor arranged radially inside the stator, with multiple coils wound around the stator to generate a rotating magnetic field (see, for example, Patent Document 1).

[0003] The electric motor described in Patent Document 1 includes an annular stator fixed in a housing and a rotor rotatably arranged radially inside the stator. The stator includes a stator core made of a magnetic material, an insulator attached to the stator core, a plurality of coils wound around the stator core via the insulator, and a busbar unit for supplying drive current to each coil. The rotor includes a rotor core made of a magnetic material and a plurality of permanent magnets provided therein. The busbar unit is arranged on one axial end side of the stator core.

[0004] The stator core of the stator has a plurality of teeth protruding radially inward from a plurality of circumferential positions, and insulators are attached to the plurality of teeth. Each coil is wound around the plurality of teeth via the insulator. The busbar unit has U-phase, V-phase, and W-phase busbars, which are held by an insulating resin block. Each busbar has a substantially C-shaped busbar body and a plurality of busbar terminals protruding radially outward from the busbar body. Each busbar terminal is disposed so as to straddle the winding portions of the coils adjacent in the circumferential direction when viewed in the axial direction. A start wire portion of one coil adjacent in the circumferential direction and an end wire portion of the other coil adjacent in the circumferential direction are connected to each busbar terminal. In addition, the busbar body of each busbar is configured to receive U-phase, V-phase, and W-phase driving currents from a power supply terminal. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-164260 Summary of the Invention [Problem to be solved by the invention]

[0006] The coil wound around each tooth has a start part where the winding begins and an end part where the winding ends, with the start part being located inside (inner layer side) of the winding part of the coil, and the end part being located outside (outer layer side) of the winding part of the coil. The area near the start part of the coil is constrained in position by the coil of the winding part that is layered on top, but the area near the end part of the coil is not constrained in position by the coil of the winding part. For this reason, the area near the end part of the coil is separately fixed to the winding part of the coil using an adhesive.

[0007] In the electric motor described above, a busbar unit is attached to the axial end of a stator (insulator) around which coils are wound, and multiple busbar terminals of the busbar unit are arranged to cover the gaps between adjacent coils from the axial outside. Therefore, the base side (the side close to the coil winding) of the start wire portion and the end wire portion of each coil are covered on the axial outside by the busbar terminal. Therefore, when fixing the coil end wire portion to the coil winding portion using an adhesive as described above, a large amount of adhesive must be poured from a position spaced from the base of the end wire portion so that it reaches the base of the end wire portion. This requires a larger amount of adhesive to be used and takes longer to harden, which increases the time required to assemble the electric motor.

[0008] SUMMARY OF THE PRESENT DISCLOSURE An object of the present invention is to provide an electric motor that can reduce the amount of adhesive used to fix the vicinity of the end portion of the coil and shorten the assembly work time. [Means for solving the problem]

[0009] an electric motor according to one aspect of the present invention includes an annular stator and a rotor arranged radially inside the stator and rotating relative to the stator, the stator including a stator core having a plurality of teeth protruding radially inward from a plurality of circumferential positions, a plurality of coils wound around each of the teeth, and a busbar unit arranged at one axial end of the stator core and supplying power to each of the coils wound around the teeth, the busbar unit having a plurality of busbar terminals arranged to straddle the winding portions of each of the coils adjacent to each other in the axial direction when viewed in the axial direction, each of the busbar terminals being provided at two positions spaced apart in the circumferential direction with a start wire connection portion to which a start wire portion of one of the adjacent coils is connected and an end wire connection portion to which an end wire portion of the other circumferentially adjacent coil is connected, and a filling opening is provided between the start wire connection portion and the end wire connection portion of each of the busbar terminals for filling an adhesive with the winding portion of the coil near the end wire portion.

[0010] When manufacturing the electric motor of this aspect, if the end wire portions of the coils wound around each tooth are to be connected to the end wire connecting portions of the bus bar terminals, the following work is carried out as a pre-process for the connection work. That is, adhesive is filled into the winding portion near the end wire portion of the coil through a filling opening provided between the start wire connection portion and the end wire connection portion of each busbar terminal. When the filled adhesive hardens, the vicinity of the end wire portion of the coil is fixed to the winding portion of the coil, and the end wire portion of the coil will not come apart from the winding portion. This makes it possible to easily and stably connect the end wire portion of the coil to the end wire connection portion of the corresponding busbar terminal. In the electric motor of this aspect, when bonding the vicinity of the end wire portion of the coil to the winding portion, the adhesive can be directly filled into the vicinity of the end wire portion of the coil through the filling opening of the busbar terminal. This prevents the adhesive from flowing into unnecessary areas other than the vicinity of the end wire portion. As a result, it is possible to reduce the amount of adhesive to be filled, and the hardening time of the adhesive can be shortened, thereby shortening the assembly work time.

[0011] The filling opening may be arranged at a position closer to a base of the end wire portion of one of the adjacent coils than to a base of the start wire portion of the other adjacent coil.

[0012] In this case, since the filling opening is positioned closer to the base of the end wire portion of one coil than to the base of the start wire portion of the other coil, the winding portion of the coil near the end wire portion can be easily and accurately filled through the filling opening.

[0013] The filling opening may be formed at a position closer to the end wire connection portion than to the start wire connection portion of the bus bar terminal.

[0014] In this case, since the filling opening is formed at a position closer to the end wire connection portion than to the start wire connection portion of each busbar terminal, it is possible to position each busbar terminal at the midpoint of the winding portions of two circumferentially adjacent coils, while shifting only the filling opening toward the base side of the start wire portion of one of the coils.

[0015] The busbar unit may include three busbars for a U phase, a V phase, and a W phase, and an insulating resin block that holds the three busbars spaced apart from one another, and each of the busbars may include a substantially C-shaped busbar main body embedded in the resin block, and the busbar terminal protruding radially outward from the busbar main body.

[0016] In this case, by positioning and fixing the busbar unit to one end of the stator core in the axial direction, the filling openings of all the busbar terminals can be positioned at positions that make it easy to fill the adhesive. Therefore, when this configuration is adopted, it is possible to facilitate the manufacture of the electric motor. Effect of the Invention

[0017] In the electric motor according to the present invention, adhesive can be filled directly near the end wire portion of the coil through the filling opening of the bus bar terminal, which reduces the amount of adhesive needed to fix the area near the end wire portion of the coil and also shortens the assembly time. [Brief description of the drawings]

[0018] [Figure 1] FIG. 2 is a side view of the electric motor according to the embodiment. [Diagram 2] FIG. 2 is a plan view of the electric motor according to the embodiment with some components removed. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 . [Figure 4] 4 is a cross-sectional view taken along line IV-IV in FIG. 2 . [Diagram 5] FIG. 2 is a perspective view of the electric motor according to the embodiment with some components removed. [Figure 6] FIG. 2 is a perspective view of the busbar unit according to the embodiment, as viewed from one side in the axial direction. [Figure 7] FIG. 4 is a perspective view of the busbar unit according to the embodiment, as viewed from the other axial side. [Figure 8] FIG. [Figure 9] FIG. 9 is an enlarged view of part IX in FIG. 8 . [Figure 10] 1 is a side view showing an example of an electric motorcycle equipped with an electric motor according to an embodiment; [Figure 11] FIG. 4 is a side view showing another example of an electric motorcycle equipped with the electric motor according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of an electric motor 1 of this embodiment, and Fig. 2 is a plan view of the electric motor 1 with some components removed, and Fig. 3 is a cross-sectional view of the electric motor 1 taken along line III-III in Fig. 2. The electric motor 1 of this embodiment shown in these figures is used, for example, as a drive source for an electric motorcycle. When used as a drive source for an electric motorcycle, the electric motor 1 can be disposed, for example, on the side of the rear wheel Wr, which is a drive wheel, as shown in FIG. 10. In this case, the power of the electric motor 1 is transmitted to the rear wheel Wr via a gear mechanism (not shown). Note that the arrangement of the electric motor 1 is not limited thereto, and the electric motor 1 can also be mounted on the vehicle body frame between the front wheel Wf and the rear wheel Wr, as shown in FIG. 11. In this case, the power of the electric motor 1 is transmitted to the rear wheel Wr via a chain 2 or a belt.

[0020] The electric motor 1 includes an annular stator 10 and a rotor 11 rotatably disposed radially inside the stator 10. A small gap (air gap) is provided between the outer circumferential surface of the rotor 11 and the stator 10. The rotor 11 has a rotating shaft 12 at its axial center. In the following, unless a direction is specifically specified, the direction along the axis o of the rotating shaft 12 is referred to as the "axial direction," the direction perpendicular to the axis o is referred to as the "radial direction," and the circumferential direction about the axis o is referred to as the "circumferential direction." Arrow A indicating the axial direction, arrow R indicating the radial direction, and arrow C indicating the circumferential direction are shown in appropriate places in the drawings.

[0021] The stator 10 and the main part of the rotor 11 inside are accommodated inside a housing 13. The housing 13 includes a substantially cylindrical case body 14, a rear cover 15 that closes one axial end of the case body 14, and a front cover 16 that closes the other axial end of the case body 14. The rear cover 15 and the front cover 16 are fixed to the case body 14 by bolts or the like. In the following description, the side of the case body 14 on which the front cover 16 is located will be referred to as the "front side," and the side on which the rear cover 15 is located will be referred to as the "rear side." Note that an arrow FR pointing to the front side is shown in the appropriate place in the drawings.

[0022] FIG. 4 is a cross-sectional view of the electric motor 1 taken along line IV-IV in FIG. 2, and FIG. 5 is a perspective view of the electric motor 1 with some parts such as the rear cover 15 removed. As shown in Figs. 2 to 5, the stator 10 is formed into a generally cylindrical shape by connecting a plurality of split cores 30 of the same shape in an annular shape. In this embodiment, the stator 10 is formed by connecting a total of 12 split cores 30. Note that in Fig. 2, only two of the 12 split cores 30 are shown in detail by dotted lines. The split cores 30 include a core portion 31, an insulator 32, and a coil 33.

[0023] The core portion 31 is formed by stacking a plurality of steel plates (magnetic bodies) in an approximately T-shape in an axial view in the axial direction. The core portion 31 includes core-back segments 31a in an arc shape in an axial view, and teeth 31b protruding radially inward from approximately the center position in the circumferential direction of the core-back segments 31a. The approximately T-shape is formed by the core-back segments 31a and the teeth 31b. The core portions 31 of the multiple split cores 30 form an annular stator core 34 by connecting both ends in the circumferential direction of the core-back segments 31a to the ends of the adjacent core-back segments 31a. In this state, each tooth 31b protrudes radially toward the axis o.

[0024] The insulators 32 are formed of an insulating resin material. The insulators 32 are attached to the outer peripheral surfaces of the teeth 31b of the corresponding core portion 31. The teeth 31b protruding radially inward from the core back divided pieces 31a of the core portion 31 have a cross section perpendicular to the radial direction formed in a substantially rectangular shape. The insulators 32 cover two faces of the substantially rectangular cross section of the teeth 31b along the axial direction and two faces on one end side and the other end side in the axial direction. That is, the insulators 32 cover the periphery of the substantially rectangular cross section of the corresponding teeth 31b. Each insulator 32 is composed of two divided blocks 32b divided in the axial direction. In FIG. 4, only the rear divided block 32b is shown.

[0025] As shown in Fig. 4, the insulator 32 has a rectangular cylindrical surrounding portion 35 surrounding the outer circumferential surface of the corresponding tooth 31b, an outer flange portion 36o extending outward (outward in the circumferential direction and the axial direction) from an end portion of the surrounding portion 35 on the radially outer side (the core-back divided piece 31a side), and an inner flange portion 36i extending outward (outward in the circumferential direction and the axial direction) from an end portion of the surrounding portion 35 on the radially inner side. A corresponding coil 33 is wound around the outer circumferential surface of the surrounding portion 35. Each coil 33 is wound around the outer circumferential surface of the surrounding portion 35 in a state where its position is restricted in the radial direction by the inner flange portion 36i and the outer flange portion 36o. Each coil 33 is wound around the outer circumferential surface of the surrounding portion 35 of the insulator 32. In this embodiment, each coil 33 is made of a rectangular wire having a substantially rectangular cross section.

[0026] 2, 4 and 5, a protruding piece 37 that protrudes radially inward is provided on the axial end of the rear side of the inner flange portion 36i of the divided block 32b on the rear side of each insulator 32. The protruding piece 37 is a block that is generally rectangular in the axial direction, and a recess 38 that is generally rectangular in the axial direction is formed on the surface facing the rear side in the axial direction. The recess 38 is open toward the rear side in the axial direction.

[0027] As shown in Figs. 4 and 5, the rear split block 32b of each insulator 32 has a thermistor housing 40 that bulges outward in a rectangular shape in the radial direction at a substantially central portion in the circumferential direction of the outer flange portion 36o. The thermistor housing 40 is disposed axially outward (on the rear side) of the outer flange portion 36o of the rear split block 32b from the end face of the rear side of the stator core 34. A thermistor 41 for detecting the temperature of the coil 33 is attached to the thermistor housing 40 of one of the insulators 32. A notch (not shown) is provided on the inner wall of the thermistor housing 40 on the radial inner side, so that the temperature detection portion of the thermistor 41 housed in the thermistor housing 40 comes into contact with the outer surface of the coil 33. Reference numeral 42 in Figs. 4 and 5 denotes a leaf spring material for pressing the thermistor 41 against the outer surface of the coil 33.

[0028] As shown in FIG. 5, a pair of coil fitting grooves 43s, 43e that open toward the rear side are formed on the rear end edge of the outer flange portion 36o of each divided block 32b. These coil fitting grooves 43s, 43e are provided on both sides in the circumferential direction sandwiching the thermistor accommodating portion 40. Each coil fitting groove 43s, 43e penetrates the outer flange portion 36o in the thickness direction. In one coil fitting groove 43s, the start portion 33s of the coil 33 wound around the corresponding tooth 31b is fitted and provisionally locked via the insulator 32. In the other coil fitting groove 43e, the end portion 33e of the coil 33 wound around the corresponding tooth 31b is fitted and provisionally locked via the insulator 32. The start portion 33s and the end portion 33e of the coil 33 fitted in the coil fitting grooves 43s, 43e are drawn out in the radial direction of the outer flange portion 36o. A start portion 33s and an end portion 33e of the coil 33 drawn out radially outward from the outer flange portion 36o are connected to bus bars 51U, 51V, and 51W, which will be described later, after the divided blocks 32b are assembled in an annular shape.

[0029] The rotor 11, which is disposed radially inside the stator 10, includes a rotor body 20 formed in a generally cylindrical shape by stacking a plurality of steel plates (magnetic bodies) in the axial direction, as shown in Fig. 3. A rotating shaft 12 is press-fitted and fixed to the center of rotation (axial center) of the rotor body 20. A plurality of generally plate-shaped permanent magnets 21 are embedded inside the rotor body 20. The plurality of permanent magnets 21 are arranged in the circumferential direction of the rotor body 20 such that the N poles and S poles alternately face radially outward. The rotor 11 of this embodiment employs a so-called "IPM (Interior Permanent Magnet) structure" in which multiple permanent magnets are embedded inside the rotor body 20, but the structure of the rotor 11 is not limited to this. The rotor 11 can also employ a so-called "SPN (Surface Permanent Magnet) structure" in which permanent magnets 21 are attached to the outer surface of the rotor body 20.

[0030] The rotating shaft 12 protrudes from the rotor body 20 at one end (rear side) and the other end (front side) in the axial direction. One axial end of the rotating shaft 12 is rotatably supported by the rear cover 15 via a bearing 22R. The other axial end of the rotating shaft 12 passes through the front cover 16 and is rotatably supported by the front cover 16 via a bearing 22F in this state. One end of the rotating shaft 12 that passes through the front cover 16 is a rotation output part 12o to which an output gear or sprocket is attached. The rotation output part 12o protrudes outward in the axial direction from the housing 13 of the electric motor 1, and when attached to the body of a motorcycle, as shown in Figs. 10 and 11, it protrudes outward in the width direction of the body.

[0031] A concave portion 23 that opens toward the rear side is formed on the rear side surface of the rear cover 15. One end of the rotating shaft 12 penetrates the rear cover 15 in the thickness direction so that an end face 12e on the rear side is exposed in the concave portion 23. A substantially disk-shaped sensor magnet 24 is fixed to the end face 12e of the rotating shaft 12. The sensor magnet 24 serves as a detection target for detecting the rotation state when the rotation state of the rotor 11 (rotating shaft 12) is detected by a rotation sensor 25 described later.

[0032] As shown in Fig. 3, a plurality of support pillars 27 are protrudingly provided within the recessed portion 23 of the rear cover 15 so as to surround the through hole 26 of the rear cover 15. A sensor unit 45 is fixed to the tip portions of these support pillars 27. The sensor unit 45 includes a rotation sensor 25 made of a magnetic resistance element, and a sensor board 46 on which the rotation sensor 25 is mounted. The sensor board 46 is fixed to the support pillars 27 so that the rotation sensor 25 faces the sensor magnet 24 on the end face 12e of the rotating shaft 12 with a small gap therebetween.

[0033] 2, the circuit on the sensor board 46 is electrically connected to a sensor connector 47 installed in the housing 13 via a sensor harness 48. A terminal portion of the sensor connector 47 is connected to a controller (not shown) by wiring (not shown). As described above, the recessed portion 23 of the rear cover 15 in which the sensor unit 45 is attached is closed by a lid member 49 shown in FIGS.

[0034] 2 to 4, a substantially annular busbar unit 50 is attached to the rear end of the insulator 32. The busbar unit 50 includes busbars 51U, 51V, and 51W for supplying drive current to the coils 33 wound around each of the teeth 31b of the stator core 34. The busbar unit 50 constitutes the stator 10 together with the stator core 34 having the teeth 31b and the coils 33 wound around each of the teeth 31b.

[0035] A drive connector 52 is attached to the case body 14 of the housing 13. The drive connector 52 is attached to the case body 14 by penetrating the peripheral wall of the case body 14 near the rear side. As shown in FIG. 2, a U-phase power terminal TU, a V-phase power terminal TV, and a W-phase power terminal TW are installed on the drive connector 52. These power terminals TU, TV, and TW penetrate the peripheral wall of the case body 14, and the inner ends of the case body 14 are electrically connected to bus bars 51U, 51V, and 51W, respectively. In addition, the outer ends of the case body 14 of each of the power terminals TU, TV, and TW are connected to a drive circuit of a controller (not shown). A drive current is supplied to the coil 33 wound around each tooth 31b of the stator 10 from the drive circuit via the power terminals TU, TV, and TW and the bus bars 51U, 51V, and 51W.

[0036] FIG. 6 is a perspective view of the busbar unit 50 as viewed from the rear side, and FIG. 7 is a perspective view of the busbar unit 50 as viewed from the front side. In the busbar unit 50, busbar bodies 51Ua, 51Va, 51Wa (see Figs. 3 and 4) of three busbars 51U, 51V, 51W are embedded in an annular resin block 53 made of insulating resin material while being spaced apart in the axial direction. Each busbar body 51Ua, 51Va, 51Wa is formed of a conductive metal plate having a substantially C-shape when viewed in the axial direction. The annular resin block 53 is fixed to the rear end of each insulator 32 of the split core 30 assembled in an annular shape. In this state, the resin block 53 is arranged so as to be concentric with the stator core 34. A specific manner in which the resin block 53 is fixed to the insulator 32 will be described in detail later.

[0037] Four busbar terminals 51Ub, 51Vb, 51Wb protruding radially outward are provided on the outer peripheral edge of each of the roughly C-shaped busbar bodies 51Ua, 51Va, 51Wa. The four busbar terminals 51Ub, 51Vb, 51Wb for the U-phase, V-phase, and W-phase are spaced apart at equal intervals in the circumferential direction of the resin block 53. Each busbar terminal 51Ub, 51Vb, 51Wb is formed integrally with the corresponding busbar body 51Ua, 51Va, 51Wa from a conductive metal plate.

[0038] Three of the four busbar terminals 51Ub for the U phase are formed in a substantially rectangular shape having a constant width along the circumferential direction of the resin block 53. The remaining one of the four busbar terminals 51Ub for the U phase has a shape in which a terminal connection portion 51Ub2 that bulges outward in a mountain shape in the radial direction is connected to a terminal base portion 51Ub1 that is substantially rectangular in shape having a constant width along the circumferential direction of the resin block 53. Similarly, three of the four busbar terminals 51Vb, 51Wb for the V phase and the W phase are formed in a substantially rectangular shape having a constant width along the circumferential direction of the resin block 53, and the remaining one of the four busbar terminals 51Vb, 51Wb for the V phase and the W phase has a shape in which a terminal connection portion 51Vb2, 51Wb2 that bulges outward in a mountain shape in the radial direction is connected to a terminal base portion 51Vb1, 51Wb1 that is substantially rectangular in shape having a constant width along the circumferential direction of the resin block 53. Terminal base portions 51Ub1, 51Vb1, 51Wb1 of the bus bar terminals 51Ub, 51Vb, 51Wb having terminal connection portions 51Ub2, 51Vb2, 51Wb2 are shaped substantially the same as the other bus bar terminals 51Ub, 51Vb, 51Wb.

[0039] A V-phase busbar terminal 51Vb is arranged on one circumferential side of each U-phase busbar terminal 51Ub, a W-phase busbar terminal 51Wb is arranged on one circumferential side of each V-phase busbar terminal 51Vb, and a U-phase busbar terminal 51Ub is arranged on one circumferential side of each W-phase busbar terminal 51Wb. The U-phase busbar terminal 51Ub, the V-phase busbar terminal 51Vb, and the W-phase busbar terminal 51Wb that are arranged adjacent to each other are equally spaced apart in the circumferential direction of the resin block 53. The busbar terminals 51Ub, 51Vb, and 51Wb of each phase having terminal connection portions 51Ub2, 51Vb2, and 51Wb2 are arranged in a concentrated manner in a specific circumferential region of the resin block 53. Terminal connection portions 51Ub2, 51Vb2, 51Wb2 of these bus bar terminals 51Ub, 51Vb, 51Wb are electrically connected to corresponding power supply terminals TU, TV, TW of the drive connector 52 (see FIG. 2).

[0040] As shown in Figs. 6 and 7, each of the busbar terminals 51Ub, 51Ub, 51Ub for the U-phase, V-phase, and W-phase is provided with a start wire connection portion 54s and a finish wire connection portion 54e for connecting the start wire portion 33s and the finish wire portion 33e (see Fig. 5) of the coil 33 wound around each tooth 31b of the stator core 34, respectively. The start wire connection portion 54s is provided near one circumferential side of the radially outer edge of each of the busbar terminals 51Ub, 51Ub, 51Ub. The finish wire connection portion 54e is provided near the other circumferential side of the radially outer edge of each of the busbar terminals 51Ub, 51Ub, 51Ub. Each of the start wire connection portion 54s and the finish wire connection portion 54e is configured to include an engagement groove 28 and a cut-and-raised piece 29.

[0041] The engagement groove 28 is a groove extending from the radially outer end of each busbar terminal 51Ub, 51Ub, 51Ub toward the radially inner side, and the cut-and-raised piece 29 is cut and raised from the bottom of the engagement groove 28 toward the rear side. The start wire portion 33s and the end wire portion 33e of the coil 33 drawn out from the coil fitting grooves 43s, 43e of the insulator 32 described above are inserted and engaged in the engagement groove 28. The start wire portion 33s and the end wire portion 33e inserted into the engagement groove 28 are drawn out to the rear side along the axial direction. In this state, the start wire portion 33s and the end wire portion 33e are welded and fixed to the corresponding cut-and-raised piece 29. The start wire portion 33s and the end wire portion 33e of each coil 33 wound around the tooth 31b are thus connected to the start wire connecting portion 54s and the end wire connecting portion 54e of the corresponding busbar terminal 51Ub, 51Ub, 51Ub.

[0042] Here, each busbar terminal 51Ub, 51Ub, 51Ub protruding radially from the annular resin block 53 is disposed at a substantially midpoint of the axial center of the winding portions (teeth 31b) of two circumferentially adjacent coils 33 as viewed in the axial direction. That is, each busbar terminal 51Ub, 51Ub, 51Ub is disposed so as to straddle the winding portions (teeth 31b) of two circumferentially adjacent coils 33 as viewed in the axial direction. The start wire connection portion 54s of each busbar terminal 51Ub, 51Ub, 51Ub is connected to the start wire portion 33s of one of the winding portions adjacent in the circumferential direction as viewed in the axial direction, and the end wire connection portion 54e is connected to the end wire portion 33e of the coil 33 of the other winding portion adjacent in the circumferential direction as viewed in the axial direction.

[0043] 4, 6 and 7, the resin block 53 of the busbar unit 50 includes an annular block main body 55 in which the substantially C-shaped busbar main bodies 51Ua, 51Va, 51Wa are embedded and spaced apart in the axial direction, and an inner flange 56 having a relatively thin wall thickness that extends radially inward from the inner periphery of the block main body 55. The inner flange 56 is formed in an annular shape and protrudes radially inward at a position closer to the front in the thickness direction (axial direction) of the block main body 55. A step 57r is provided between the block main body 55 and a base (radially outer end) of the rear side surface of the inner flange 56.

[0044] 6, twelve reinforcing ribs 58 are provided at equal intervals in the circumferential direction on the rear side surface of the inner flange portion 56 of the resin block 53. Each reinforcing rib 58 bulges out toward the rear side from the rear side surface of the inner flange portion 56 by a predetermined thickness, and extends radially inward from a step portion 57r between the block main body portion 55 and the inner flange portion 56. This increases the radial bending rigidity of the portion of the inner flange portion 56 where the reinforcing ribs 58 are arranged.

[0045] Each reinforcing rib 58 is disposed at a circumferential position corresponding to the intermediate position between adjacent bus bar terminals 51Ub, 51Vb, 51Wb in the circumferential direction. An adhesive filling port 59 that vertically penetrates the resin block 53 is formed at approximately the center of each reinforcing rib 58 in the extension direction (radial direction). Details of the adhesive filling port 59 will be described later.

[0046] As shown in Figures 4 and 7, a ring-shaped protrusion 60 is provided on the front side surface of the block body 55 of the resin block 53. The protrusion 60 is provided along the inner peripheral edge of the block body 55. The front end face of the protrusion 60 is provided with twelve locking projections 61 spaced equally apart in the circumferential direction. The front end face of the protrusion 60 is capable of abutting against the rear end face of the outer flange portion 36o of each insulator 32 of the stator 10 (see Figures 4 and 5).

[0047] Furthermore, between the outer flange portions 36o of the insulators 32 adjacent to each other in the circumferential direction, engagement recesses 44 (see FIG. 5) that open toward the rear side are formed. A plurality of locking projections 61 protruding from the protruding stripe portion 60 of the resin block 53 are adapted to be able to fit into the engagement recesses 44 between the insulators 32. The resin block 53 (busbar unit 50) is positioned in the circumferential direction with respect to the stator core 34 by fitting the plurality of locking projections 61 into the engagement recesses 44 between the insulators 32. In addition, when the multiple locking projections 61 of the resin block 53 are fitted into the engagement recesses 44 between the insulators 32, the inner flange portion 56 and the reinforcing ribs 58 bulge radially inward beyond the tips of the teeth 31b of the stator 10.

[0048] As shown in Figs. 4 and 7, twelve rectangular pillar-shaped bosses 62 are provided on the front side of the inner flange 56 of the resin block 53 at equal intervals in the circumferential direction to protrude toward the front side. Each boss 62 is provided at a position overlapping with each reinforcing rib 58 provided on the rear side of the inner flange 56 in the axial direction. Each boss 62 is provided at a circumferential position corresponding to the intermediate position between each of the busbar terminals 51Ub, 51Vb, and 51Wb adjacent in the circumferential direction. In addition, each boss 62 protrudes at its tip in the axial direction so as to face each of the protruding pieces 37 protruding from the rear side of the insulators 32. The tip of each boss 62 is inserted into a recess 38 (see Figs. 4 and 5) formed in the protruding piece 37 of the insulator 32. The recess 38 of the protruding piece 37 is formed to have a sufficiently larger capacity than the tip of the boss 62 to be inserted. The gap between the recess 38 and the boss 62 is a filled portion that is filled with adhesive 63 (see FIG. 4). Each boss 62 inserted into the recess 38 of the protruding piece 37 is fixed to the corresponding protruding piece 37 by the adhesive 63 (see FIG. 4) filled in the recess 38.

[0049] Each boss 62 of the resin block 53 is formed to be continuous with an adhesive filling port 59 provided in the reinforcing rib 58 of the inner flange 56. The adhesive filling port 59 is formed to reach the front end face of each boss 62. The adhesive filling port 59 is formed in a funnel shape such that the opening area gradually narrows from the rear end face of the reinforcing rib 58 toward the front end face of the boss 62. With the corresponding boss 62 on the resin block 53 inserted in the recess 38 of the protruding piece 37 on the insulator 32 side, adhesive 63 is filled from the rear side of the resin block 53 through the adhesive filling port 59. When the adhesive 63 filled in the recess 38 in this manner hardens, the resin block 53 of the busbar unit 50 is fixed to the end of the rear side of the insulator 32.

[0050] When the resin block 53 of the busbar unit 50 is fixed to the rear end of the insulator 32 as described above, the inner flange portion 56 including the reinforcing ribs 58 of the resin block 53 and the boss portion 62 bulge radially inward beyond the teeth 31b of the stator core 34. When the stator 10 and the rotor 11 are assembled into the housing 13 together with the sensor unit 45 and the like, the inner flange portion 56 and the boss portion 62 bulge radially inward beyond the outer circumferential surface of the rotor 11 between the rotor 11 and the sensor unit 45 by a predetermined amount.

[0051] FIG. 8 is a plan view of the stator 10 as viewed from the rear side, and FIG. 9 is an enlarged view of part IX in FIG. A circular filling opening 65 is formed at approximately the center of the circumferential direction of each busbar terminal 51Ub, 51Ub, 51Ub (between the start line connection portion 54s and the end line connection portion 54e). The filling opening 65 penetrates each busbar terminal 51Ub, 51Ub, 51Ub in the thickness direction. The filling opening 65 of each busbar terminal 51Ub, 51Ub, 51Ub opens in approximately the middle region of each of two coils 33 adjacent in the circumferential direction when viewed in the axial direction. More specifically, the filling opening 65 opens to face the outer surfaces of the outermost layers of the winding portions of the two coils 33 and to face the vicinity of the base of the end line portion 33e of one of the coils 33.

[0052] To be precise, the position of the filling opening 65 in each busbar terminal 51Ub, 51Ub, 51Ub is not the exact center position in the circumferential direction of each terminal, but is a position biased toward the end line connecting portion 54e from the center position. In other words, in each busbar terminal 51Ub, 51Ub, 51Ub, the filling opening 65 is disposed at a position closer to the end line connecting portion 54e than to the start line connecting portion 54s. In this embodiment, the filling opening 65 is shifted toward the end line connecting portion 54e by a central angle of 1° centered on the axis o with respect to the circumferential center position of each bus bar terminal 51Ub, 51Ub, 51Ub. The diameter of the filling opening 65 is set to approximately 5 mm from the viewpoints of maintaining the strength of each bus bar terminal 51Ub, 51Ub, 51Ub and suppressing current density (suppressing heat generation due to increased current density).

[0053] The filling opening 65 is used as a filling port for adhesive 70 (Figure 9) when adhesively fixing the base of the end wire portion 33e to the winding portion of the coil 33 as a preliminary process for connecting the end wire portion 33e of each coil 33 to the end wire connection portion 54e of the bus bar terminals 51Ub, 51Ub, 51Ub. When actually adhering and fixing the base of the end wire portion 33e to the winding portion of the coil 33, the tip of the nozzle of a filling device (not shown) is inserted into the filling opening 65 from the axial outside of the busbar terminals 51Ub, 51Ub, 51Ub, and adhesive 70 discharged from the nozzle is filled into the winding portion of the coil 33 on the base side of the end wire portion 33e. At this time, the tip of the nozzle can be brought sufficiently close to the winding portion on the base side of the end wire portion 33e through the filling opening 65. Therefore, as shown in FIG. 9, a necessary and sufficient amount of adhesive 70 can be filled into the winding portion on the base side of the end wire portion 33e. When the filled adhesive 70 hardens in this way, the end wire portion 33e is fixed to the winding portion of the coil 33, and the end wire portion 33e does not separate (disintegrate) from the winding portion.

[0054] <Operation of electric motor 1> A three-phase drive current is supplied to the multiple coils 33 of the stator 10 through a drive circuit of the controller. When the drive current is supplied to the coils 33 in this manner, a rotating magnetic field is generated in the stator 10. As a result, the rotor 11 receives torque from the rotating magnetic field and begins to rotate in a predetermined direction. At this time, the rotation of the rotor 11 is detected by a sensor unit 45 disposed opposite to the rear side of the rotating shaft 12. Rotation information of the rotating shaft 12 detected by the sensor unit 45 is output to a controller, and the controller controls the drive current based on the rotation information.

[0055] <Effects of the embodiment> As described above, in the electric motor 1 of this embodiment, the filling openings 65 are provided between the start wire connection portions 54s and the end wire connection portions 54e of each busbar terminal 51Ub, 51Ub, 51Ub of the busbar unit 50. Therefore, when bonding the vicinity of the end wire portion 33e of the coil 33 to the winding portion, the adhesive 70 can be directly filled in the vicinity of the end wire portion 33e of the coil 33 through the filling openings 65 of the busbar terminals 51Ub, 51Ub, 51Ub. Therefore, when the electric motor 1 of this embodiment is used, the adhesive 70 is less likely to flow into unnecessary areas other than the vicinity of the end line portion 33e, and as a result, it is possible to reduce the amount of adhesive 70 filled in. Furthermore, since the amount of adhesive 70 filled in can be reduced in this way, the curing time of the adhesive 70 can be shortened, and the assembly time of the electric motor 1 can be shortened.

[0056] Therefore, by adopting the electric motor 1 of this embodiment, it is possible to reduce the amount of adhesive 70 used and improve the efficiency of the assembly work. As a result, it is possible to contribute to Goal 7 of the Sustainable Development Goals (SDGs) led by the United Nations, which is to "Ensure access to affordable, reliable, sustainable and modern energy for all."

[0057] Furthermore, in the electric motor 1 of this embodiment, the filling openings 65 of each bus bar terminal 51Ub, 51Ub, 51Ub are disposed at a position closer to the base of the end wire portion 33e of the other adjacent coil 33 than to the base of the start wire portion 33s of one adjacent coil 33. For this reason, when the electric motor 1 of this embodiment is employed, the vicinity of the end wire portion 33e can be easily and accurately filled into the winding portion of the other coil 33 through the filling openings 65 of each bus bar terminal 51Ub, 51Ub, 51Ub.

[0058] In particular, in the electric motor 1 of this embodiment, the filling opening 65 is formed at a position closer to the end wire connection portion 54e than to the start wire connection portion 54s of each bus bar terminal 51Ub, 51Ub, 51Ub. Therefore, while each bus bar terminal 51Ub, 51Ub, 51Ub is positioned at the middle position of the winding portions of two circumferentially adjacent coils 33, only the filling opening 65 can be shifted toward the base side of the start wire portion 33s of one coil 33. Therefore, when this configuration is adopted, the bus bar terminals 51Ub, 51Ub, 51Ub can be installed more easily. However, it is also possible to form the filling opening 65 at a midpoint between the start line connection portion 54s and the end line connection portion 54e of the busbar terminals 51Ub, 51Ub, 51Ub, and shift the entire busbar terminals 51Ub, 51Ub, 51Ub toward the end line portion 33e so that the filling opening 65 is close to the vicinity of the end line portion 33e of the other coil 33.

[0059] Furthermore, in the electric motor 1 of this embodiment, a plurality of busbar terminals 51Ub, 51Ub, 51Ub having filling openings 65 are integrated into the annular busbar unit 50. In other words, the busbar unit 50 includes busbars 51U, 51V, 51W and an insulating resin block 53 that holds the busbars 51U, 51V, 51W in a state where they are spaced apart from each other, and each of the busbars 51U, 51V, 51W includes a substantially C-shaped busbar main body 51Ua, 51Va, 51Wa embedded in the resin block 53, and busbar terminals 51Ub, 51Ub, 51Ub protruding radially outward from the busbar main bodies 51Ua, 51Va, 51Wa. Therefore, by positioning and fixing the busbar unit 50 to one axial end side of the stator core 34 (insulator 32), the filling openings 65 of all of the busbar terminals 51Ub, 51Ub, 51Ub can be disposed at positions that facilitate the filling operation of the adhesive 70. Therefore, when the electric motor 1 of this embodiment is adopted, the manufacture of the electric motor 1 can be simplified.

[0060] The present invention is not limited to the above embodiment, and various design changes are possible without departing from the spirit of the present invention. For example, in the above embodiment, the stator 10 is formed of twelve divided cores 30, but the number of divided cores 30 constituting the stator 10 may be other than twelve.

[0061] In the above embodiment, portions of the three bus bars 51U, 51V, 51W of the U-phase, V-phase, and W-phase are embedded inside the common resin block 53. However, the bus bars 51U, 51V, 51W do not have to be integrated with the resin block 53. For example, the bus bars 51U, 51V, 51W may each be engaged and fixed to an insulating holding member. [Explanation of symbols]

[0062] 1...electric motor, 2...chain, 10...stator, 11...rotor, 12...rotating shaft, 12e...end face, 12o...rotation output portion, 13...housing, 14...case body, 15...rear cover, 16...front cover, 20...rotor body, 21...permanent magnet, 22F, 22R...bearing, 23...concave portion, 24...sensor magnet, 25...rotation sensor, 26...through hole, 27...support portion, 28...engagement groove, 29... Cut-and-raised piece, 30... divided core, 31... core portion, 31a... core back divided piece, 31b... teeth, 32... insulator, 32b... divided block, 33... coil, 34... stator core, 35... surrounding portion, 36i... inner flange portion, 36o... outer flange portion, 37... protruding piece, 37... recess, 40... thermistor accommodating portion, 41... thermistor, 42... leaf spring, 43s, 43e... coil fitting groove, 44... engagement Mating recess, 45... sensor unit, 46... sensor board, 47... sensor connector, 48... sensor harness, 49... cover member, 50... bus bar unit, 51U, 51V, 51W... bus bar, 51Ua, 51Va, 51Wa... bus bar main body, 51Ub, 51Vb, 51Wb... bus bar terminal, 51Ub1, 51Vb1, 51Wb1... terminal base, 51Ub2, 51Vb2, 51Wb2... terminal Connection part, 52...drive connector, 53...resin block, 54s...connection part for starting line, 54e...connection part for ending line, 55...block main body, 56...inner flange, 57r...step, 58...reinforcing rib, 59...adhesive filling port, 60...projection, 61...locking projection, 62...boss, 63...adhesive, 65...filling opening, 70...adhesive, TU,TV,TW...power terminal, o...axis center, Wf...front wheel, Wr...rear wheel.

Claims

1. An annular stator; a rotor disposed radially inside the stator and rotating relative to the stator; The stator includes: a stator core having a plurality of teeth protruding radially inward from a plurality of circumferential positions; A plurality of coils are wound around each of the teeth; a bus bar unit that is disposed on one end side of the stator core in an axial direction and supplies power to each of the coils wound around the teeth, the busbar unit includes a plurality of busbar terminals arranged across winding portions of the coils adjacent to each other in a circumferential direction when viewed in an axial direction, each bus bar terminal is provided at two positions spaced apart in the circumferential direction with a start wire connection portion to which a start wire portion of one of the adjacent coils is connected and an end wire connection portion to which an end wire portion of the other of the circumferentially adjacent coils is connected; an opening for filling an adhesive into a winding portion of the coil near the end portion is provided between the start wire connection portion and the end wire connection portion of each of the bus bar terminals.

2. 2. The electric motor according to claim 1, wherein the filling opening is disposed at a position closer to a base of the end portion of one of the adjacent coils than to a base of the start portion of the other adjacent coil.

3. 3. The electric motor according to claim 2, wherein the filling opening is formed at a position closer to the end wire connection portion than to the start wire connection portion of the bus bar terminal.

4. The busbar unit includes: Three bus bars for U phase, V phase, and W phase; an insulating resin block that holds the three bus bars in a spaced-apart state; Each of the bus bars is a substantially C-shaped bus bar body embedded in the resin block; The electric motor according to claim 1 , further comprising: the bus bar terminals protruding radially outward from the bus bar body.

Images