Rotating Electric Machine

Abstract

To reduce a dragging loss while securing a flow amount of a coolant fluid without providing a flow hole to a stator core.SOLUTION: A stator 14 of a rotary electric machine 10 includes: (a) a stator core 30 in which a plurality of teeth projected to an inner peripheral side of a cylinder shape while forming the cylinder shape is provided with a predetermined gap 36 to a peripheral direction around a center line O; (b) a plurality of coils 38 that is distributed into the gap 36 so as to be wound to the plurality of teeth; and (c) a plurality of mold resin parts 40 that covers each coil 38 so as to fill a resin material so as to embed the gap 36, respectively with a lid, and forms an inner peripheral surface of the stator 14 so that a front surface 40f blocking the gap 36 is an almost surface with a projection surface 34f of each tooth, and (d) a groove 42 is provided to a shaft direction parallel to the center line O in the front surface 40f of at least one part mold resin part 40 of the plurality of mold resin parts 40.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a rotating electric machine, and more particularly to a rotating electric machine having a stator in which gaps between a plurality of teeth are filled with a resin material. [Background technology]

[0002] A rotating electric machine including a cylindrical stator and a rotor arranged on the inner periphery of the stator so as to be rotatable around a center line common to the stator is widely known. The stator includes (a) a stator core having a cylindrical shape and a plurality of teeth protruding to the inner periphery of the cylindrical shape, which are arranged at a predetermined gap in the circumferential direction around the center line, (b) a plurality of coils arranged in the gaps so as to be wound around the teeth, and (c) a plurality of molded resin parts that are filled with a resin material so as to fill the gaps, cover the coils, and the surfaces that close the gaps are substantially flush with the protruding surfaces of the teeth to form the inner periphery of the stator. The stator described in Patent Document 1 is one example, and a support member such as a foamed resin material is provided in the gaps as the molded resin parts. In Patent Document 1, the stator core is provided with flow holes for discharging the cooling fluid, thereby reducing loss due to drag rotation of the rotor caused by stagnation of the cooling fluid (hereinafter referred to as drag loss). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-78226 Summary of the Invention [Problem to be solved by the invention]

[0004] However, providing the stator core with through holes obstructs the flow of magnetic flux, which may reduce the efficiency of the rotating electrical machine and cause a decrease in torque, etc. This problem is not limited to electric motors, but also applies to generators.

[0005] The present invention has been made against the background of the above circumstances, and its object is to ensure the flow rate of cooling fluid and reduce drag loss without providing flow holes in the stator core. [Means for solving the problem]

[0006] In order to achieve the above object, a first invention provides a rotating electric machine comprising: (a) a cylindrical stator; and a rotor disposed on an inner circumferential side of the stator so as to be rotatable about a center line common to the stator; (b) the stator comprises: (b-1) a stator core formed in a cylindrical shape, and including a plurality of teeth protruding to an inner circumferential side of the cylindrical shape and disposed at predetermined gaps in a circumferential direction about the center line; (b-2) a plurality of coils disposed in the gaps so as to be wound around the plurality of teeth; and (b-3) a plurality of molded resin portions which are filled with a resin material so as to fill each of the gaps, thereby covering the coils, and whose surfaces closing the gaps are substantially flush with the protruding surfaces of the teeth to form an inner circumferential surface of the stator; and (c) a groove is provided in the surface of at least a portion of the molded resin portions among the plurality of molded resin portions in an axial direction parallel to the center line. (d) a total number of the grooves provided on the surface of the molded resin portion at the plurality of locations is different from the number of the teeth. It is characterized by the fact that In addition, in a cross section perpendicular to the axial direction, the groove is formed so that it is recessed toward the outer periphery from a virtual surface (curve or broken line) of the gap portion obtained by extending the protruding surface of the tooth.

[0008] No. 2 The invention relates to (a) a rotating electric machine comprising: (a) a cylindrical stator; and a rotor disposed on an inner periphery of the stator so as to be rotatable about a center line common to the stator; (b) the stator comprises: (b-1) a stator core formed in a cylindrical shape, and including a plurality of teeth protruding to an inner periphery of the cylindrical shape and disposed at predetermined gaps in a circumferential direction about the center line; (b-2) a plurality of coils disposed in the gaps so as to be wound around the plurality of teeth; and (b-3) a plurality of molded resin portions each having a surface filled with a resin material to fill the gaps, covering the coils, the surfaces of which closing the gaps are substantially flush with the protruding surfaces of the teeth, and forming an inner periphery of the stator; (c) the surfaces of at least some of the molded resin portions among the plurality of molded resin portions are provided with grooves in an axial direction parallel to the center line; and (e) The number of the grooves provided on the surface of each of the molded resin portions at the plurality of locations is different. The number of grooves provided on the surface of one molded resin portion may be zero, for example, there may be two types of grooves, 0 and 1.

[0009] No. 3 The invention relates to (a) a rotating electric machine comprising: (a) a cylindrical stator; and a rotor disposed on an inner periphery of the stator so as to be rotatable about a center line common to the stator; (b) the stator comprises: (b-1) a stator core formed in a cylindrical shape, and including a plurality of teeth protruding to an inner periphery of the cylindrical shape and disposed at predetermined gaps in a circumferential direction about the center line; (b-2) a plurality of coils disposed in the gaps so as to be wound around the plurality of teeth; and (b-3) a plurality of molded resin portions each having a surface filled with a resin material to fill the gaps and cover the coils, the surface closing the gaps being substantially flush with the protruding surfaces of the teeth to form an inner periphery of the stator; (c) the surface of at least a portion of the molded resin portions among the plurality of molded resin portions is provided with a groove in an axial direction parallel to the center line; and (f) the rotor is supported by a support member so as to be rotatable about the center line, and a resolver is disposed between the support member and the rotor in the axial direction, (g) A cylindrical resolver in-low that positions and holds a resolver stator therein is provided on the support member so as to protrude toward the rotor, and the resolver in-low is provided with slits extending in the axial direction at a plurality of positions around the center line, (h) The groove is characterized in that it is provided including a position that coincides with at least one of the plurality of slits around the center line. Effect of the Invention

[0010] The first invention In a rotating electric machine, at least some of the molded resin parts among the multiple molded resin parts in which the gaps in the stator core are filled with a resin material are provided with grooves in the axial direction on their surfaces, so that a cross section for the cooling fluid is secured between the outer circumferential surface of the rotor, and the cooling fluid can flow smoothly in the axial direction through the grooves, thereby reducing drag loss caused by stagnation of the cooling fluid. In this case, since it is not necessary to provide the stator core with a flow hole for discharging the cooling fluid, there is no risk of impeding the flow of magnetic flux, and the efficiency of the rotating electric machine is maintained at a good level. In addition, since the total number of grooves is different from the number of teeth, the occurrence of vibrations and abnormal noise is suppressed. That is, a pressure difference occurs in the cooling fluid depending on the presence or absence of grooves, and the rotor experiences rotational fluctuations due to the pressure difference, while a rotating electric machine experiences torque fluctuations corresponding to the number of teeth, and the rotational fluctuations caused by the torque fluctuations and the rotational fluctuations caused by the pressure difference may resonate with each other, causing worsening vibrations and abnormal noise. However, if the total number of grooves is different from the number of teeth, resonance is suppressed, and the occurrence of vibrations and abnormal noise is suppressed.

[0012] No. 2 invention Rotating Electric Machine So, Since at least some of the molded resin parts among the multiple molded resin parts in which the voids in the stator core are filled with a resin material have grooves in the axial direction on their surfaces, a cross section for the cooling fluid is secured between the outer circumferential surface of the rotor, allowing the cooling fluid to flow smoothly in the axial direction through the grooves, thereby reducing drag loss caused by stagnation of the cooling fluid. In this case, since there is no need to provide the stator core with flow holes for discharging the cooling fluid, there is no risk of impeding the flow of magnetic flux, and the efficiency of the rotating electric machine is maintained at a good level. Also, Since the number of grooves provided on the surface of each of the multiple molded resin parts is different, the rotational fluctuations of the rotor caused by the pressure difference in the cooling fluid resulting from the presence or absence of grooves become irregular, and resonance with the torque fluctuations of the rotating electric machine is suppressed, thereby suppressing the generation of vibrations and abnormal noise.

[0013] No. 3 invention Rotating Electric Machine So, Since at least some of the molded resin parts among the multiple molded resin parts in which the voids in the stator core are filled with a resin material have grooves in the axial direction on their surfaces, a cross section for the cooling fluid is secured between the outer circumferential surface of the rotor, allowing the cooling fluid to flow smoothly in the axial direction through the grooves, thereby reducing drag loss caused by stagnation of the cooling fluid. In this case, since there is no need to provide the stator core with flow holes for discharging the cooling fluid, there is no risk of impeding the flow of magnetic flux, and the efficiency of the rotating electric machine is maintained at a good level. Also, A resolver in-row that positions and holds the resolver stator is provided on the support member, and a groove is provided including a position that coincides with the slit provided in the resolver in-row.Since the cooling fluid that flows axially through the groove is discharged into the slit, stagnation of the cooling fluid is suppressed regardless of the presence of the resolver in-row, and drag loss is appropriately reduced. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic cross-sectional view perpendicular to a center line O, illustrating a rotating electric machine according to an embodiment of the present invention. [Diagram 2] 2 is a schematic axial cross-sectional view of the portion viewed from the arrows II-II in FIG. 1. [Diagram 3] FIG. 2 is an enlarged cross-sectional view of a portion III in FIG. [Figure 4] FIG. 5 is a cross-sectional view corresponding to FIG. 3 and is for explaining another embodiment of the present invention. [Diagram 5] FIG. 7 is a schematic cross-sectional view taken along the line perpendicular to the center line O in the direction of arrows VV in FIG. 6, illustrating yet another embodiment of the present invention. [Figure 6] 6 is a schematic axial cross-sectional view of the portion viewed from the arrows VI-VI in FIG. 5. [Figure 7] FIG. 11 is a schematic cross-sectional view corresponding to FIG. 1 and explains still another embodiment of the present invention. [Figure 8] FIG. 11 is a schematic cross-sectional view corresponding to FIG. 1 and explains still another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A rotating electric machine is a rotating electrical machine, sometimes called a rotating machine, and is a motor generator used as an electric motor or a generator, or both, such as a permanent magnet type three-phase AC synchronous motor. The present invention is applied to an electric vehicle rotating electric machine used as a driving force source for driving an electric vehicle such as an electric car or a hybrid vehicle, but is also applied to various rotating electric machines such as a generator of a series type hybrid vehicle, and an electric motor or generator for non-vehicle use. The cross-sectional shape of the groove provided on the surface of the molded resin part can be various forms such as a V-shape, a U-shape, a circular arc shape, a square shape, etc. The number of grooves provided on the surface of one molded resin part is suitably 0 to 2, but it is also possible to provide 3 or more. EXAMPLES

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that in the following embodiments, the drawings are appropriately simplified or modified for the purpose of explanation, and the dimensional ratios, angles, shapes, etc. of each part are not necessarily drawn accurately.

[0017] FIG. 1 is a schematic cross-sectional view perpendicular to a center line O, illustrating a rotating electric machine 10 according to an embodiment of the present invention. FIG. 2 is a schematic axial cross-sectional view cut along the center line O, and is a cross-sectional view of the II-II arrow portion in FIG. 1. The rotating electric machine 10 is a three-phase AC synchronous motor with embedded permanent magnets, and is a motor generator that can be used alternatively as an electric motor or a generator, and is an electric vehicle rotating electric machine used as a driving force source for running an electric vehicle such as a hybrid vehicle. The rotating electric machine 10 includes a rotor 12 and a stator 14 that are arranged concentrically with the center line O. In the description of this embodiment, the center line O of the rotating electric machine 10 is also used as the center line of the rotor 12, the stator 14, and the rotor shaft 20.

[0018] The rotor 12 includes a cylindrical rotor core 22 attached to the outer circumferential surface of a rotor shaft 20 and a permanent magnet (not shown) embedded in the rotor core 22, and is disposed in a case (not shown) so as to be rotatable about a center line O via the rotor shaft 20. The rotor core 22 is formed by laminating a number of annular steel plates 24 in the axial direction, i.e., in a direction parallel to the center line O, in an attitude perpendicular to the center line O, and is fixed to the rotor shaft 20 via screws (not shown) or the like. An axial center portion of the rotor shaft 20 is provided with an axial flow hole 26 through which a cooling fluid flows, and a radial flow hole 28 is provided in a portion to which the rotor core 22 is fixed so as to communicate with the axial flow hole 26, and the cooling fluid supplied to the axial flow hole 26 flows out from the radial flow hole 28 to the outside and is supplied to the rotor core 22. This cooling fluid flows through the gaps between the numerous steel plates 24 of the rotor core 22 to the outer circumferential surface of the rotor 12 by centrifugal force or the like, but if necessary, radial flow holes may be provided in the rotor core 22 .

[0019] The stator 14 includes a cylindrical stator core 30 disposed on the outer periphery of the rotor 12. The stator core 30 is formed by laminating a number of annular steel plates 32 in the axial direction, i.e., in a direction parallel to the center line O, perpendicular to the center line O, and is fixed to a case (not shown) by press-fitting or by means of mounting bolts. The stator core 30 is provided with a plurality of teeth 34 (15 in this embodiment) protruding toward the inner periphery of the cylinder at equal angular intervals with a predetermined gap 36 in the circumferential direction around the center line O. The teeth 34 are provided parallel to the center line O over the entire axial length of the stator core 30, and the gap 36 is provided penetrating the stator core 30 in the axial direction, and a coil 38 is wound around each of the teeth 34. In this embodiment, the coil 38 is wound around 14 teeth 34 except for one tooth 34a diagonally below the right side in FIG. 1. The coils 38 wound around the teeth 34 are arranged so as to be housed within the respective gaps 36, and each of the multiple gaps 36 is filled with an insulating resin material such as epoxy resin to provide a molded resin portion 40, which covers and fixes the coils 38.

[0020] FIG. 3 is an enlarged cross-sectional view of the III portion in FIG. 1. The molded resin portion 40 is provided to close the opening of the gap 36, and its surface 40f is formed to be substantially flush with the protruding surface (inner peripheral side tip surface) 34f of the teeth 34 to form the inner peripheral surface of the stator 14. In this embodiment, the protruding surface 34f of the teeth 34 forms a cylindrical surface centered on the center line O, and the surface 40f of the molded resin portion 40 is also a cylindrical surface centered on the center line O at both ends in the circumferential direction that contact the teeth 34. As shown in FIG. 2, the molded resin portion 40 is provided integrally with the end covering portion 40e that covers the coil end 38e of the coil 38 that protrudes axially outward from the stator core 30. Note that hatching representing the cross section of the coil 38 and the molded resin portion 40 is omitted in FIG. 1. The same is true for FIG. 5, FIG. 7, and FIG. 8 corresponding to FIG. 1.

[0021] The inner diameter of the stator 14, i.e., the diameter of the protruding surface 34f of the teeth 34, is slightly larger than the outer diameter of the rotor 12, and a small gap is provided between the cylindrical outer peripheral surface of the rotor 12 and the cylindrical inner peripheral surface of the stator 14. Therefore, the cooling fluid supplied from the axial flow hole 26 of the rotor shaft 20 through the radial flow hole 28 to the rotor core 22, circulates through the rotor core 22 by centrifugal force or the like, and flows out to the outer peripheral surface of the rotor 12, and is discharged in the axial direction of the rotating electric machine 10 through the gap between the inner peripheral surface of the stator 14. However, if the gap dimension is small, a sufficient flow rate cannot be obtained, and drag loss may increase due to the stagnation of the cooling fluid. For this reason, in this embodiment, a groove 42 extending in the axial direction parallel to the center line O is provided on the surface 40f of the molded resin part 40 forming the inner peripheral surface of the stator 14, making it easier for the cooling fluid to flow.

[0022] That is, the molded resin portion 40 is provided so as to fill all the gaps 36 between the teeth 34, and all the surfaces 40f closing the openings of the gaps 36 are provided with one groove 42 in the axial direction parallel to the center line O for circulating the cooling fluid. In the cross-sectional view perpendicular to the center line O shown in FIG. 3, the groove 42 is formed so as to be recessed toward the outer periphery side from a virtual surface (a cylindrical surface centered on the center line O) fv when the protruding surface 34f of the tooth 34 is extended to the gap 36 portion, and in this embodiment, the groove 42 has a V-shaped cross section. This groove 42 is provided in a range that is longer than at least the entire axial length of the rotor 12 in FIG. 2 and extends to both sides of the rotor 12 in the axial direction, and in this embodiment, it is provided over the entire length of the stator 14 including the end covering portion 40e that covers the coil end 38e. For example, when the molded resin portion 40 is injection molded by filling all of the gaps 36 at multiple locations where the coils 38 are arranged with resin material, such grooves 42 can be formed simultaneously on the surface 40f of all of the molded resin portions 40 located at multiple locations in the circumferential direction across the teeth 34 by providing a protrusion with a triangular cross section that corresponds to the cross-sectional shape of the grooves 42 on the molding surface of the mold used for the injection molding.

[0023] In the rotating electric machine 10 of this embodiment, grooves 42 are provided in the axial direction on all the surfaces 40f of the molded resin portion 40 at a plurality of locations where the gaps 36 of the stator core 30 are filled with a resin material, so that a cross section for the flow of the cooling fluid is secured between the outer circumferential surface of the rotor 12, and the cooling fluid supplied from the rotor shaft 20 to the rotor core 22 flows radially outward in the rotor core 22 by centrifugal force or the like, as shown by arrow A in Fig. 2, and then flows smoothly in the axial direction through the grooves 42, thereby reducing drag loss caused by the stagnation of the cooling fluid. In this case, there is no need to provide a flow hole in the stator core 30 to discharge the cooling fluid as in Patent Document 1, so there is no risk of impeding the flow of magnetic flux, and the efficiency of the rotating electric machine 10 is maintained at a good level.

[0024] In this embodiment, the grooves 42 are provided on all the surfaces 40f of the multiple (15) molded resin portions 40, so that the flow rate of the cooling fluid can be sufficiently ensured and retention can be appropriately suppressed. In this embodiment, the molded resin portions 40 are provided by simultaneously filling the multiple gaps 36 with resin material by injection molding, so that the grooves 42 can be provided on the surfaces 40f simply by providing a triangular ridge in cross section corresponding to the cross-sectional shape of the grooves 42 on the molding die for the injection molding. This can be easily implemented, suppressing an increase in processing costs, and reducing the amount of resin material required by the grooves 42, thereby saving material costs.

[0025] In addition, Patent Document 1 describes a technique for discharging a cooling fluid by providing a circulation hole in the molded resin, but in that case, it is assumed that cracks will occur and grow from the circulation hole, causing the molded resin to fall off, but in this embodiment, it is only necessary to provide grooves 42 on surface 40f of molded resin part 40, so there is a low possibility of cracks occurring or molded resin part 40 falling off. In addition, since post-processing for providing circulation holes is not required, an increase in manufacturing costs is suppressed.

[0026] Next, another embodiment of the present invention will be described. In the following embodiment, the parts that are substantially the same as those in the above embodiment are given the same reference numerals and detailed description thereof will be omitted.

[0027] 4 is a cross-sectional view corresponding to FIG. 3, in which a pair of grooves 50, 52 are provided on the surface 40f of the molded resin part 40 over the entire axial length instead of the groove 42. In this case, the grooves 50, 52 promote the discharge of the cooling fluid, reducing drag loss caused by the stagnation of the cooling fluid, and other effects similar to those of the above embodiment can be obtained. In addition, the grooves 50, 52 are spaced unequal around the center line O, and the total number of the grooves 50, 52 is twice that of the teeth 34, thereby suppressing the generation of vibrations and abnormal noise. In other words, the presence or absence of grooves 50, 52 creates a pressure difference in the cooling fluid, and this pressure difference causes rotational fluctuations in rotor 12, while torque fluctuations occur in rotating electric machine 10 in accordance with the number of teeth 34. There is a possibility that the rotational fluctuations caused by the torque fluctuations and the rotational fluctuations caused by the pressure difference will resonate with each other, resulting in worsening vibrations and abnormal noise. However, since the total number of grooves 50, 52 is different from the number of teeth 34 and the grooves 50, 52 are unevenly spaced, the occurrence of vibrations and abnormal noise due to resonance is suppressed.

[0028] 5 and 6 show a rotating electric machine 60 in which a resolver 62 is provided adjacent to the rotor 12 in the axial direction, and FIG. 5 is a schematic cross-sectional view perpendicular to the center line O in the portion seen by the arrows VV in FIG. 6, and FIG. 6 is a schematic axial cross-sectional view in the portion seen by the arrows VI-VI in FIG. 5. The rotor 12, the stator 14, and the rotor shaft 20 are configured in the same manner as in the above-mentioned embodiment, and one end of the rotor shaft 20 is supported by a rear cover 66 via a bearing 64 so as to be rotatable about the center line O. The rear cover 66 corresponds to a support member, and constitutes a part of the case of the rotating electric machine 60 to which the stator 14 is fixed. In other words, this rotating electric machine 60 is a rotating electric machine with a built-in resolver.

[0029] The resolver 62 is disposed between the rear cover 66 and the rotor 12 in the axial direction, and includes a resolver rotor 68 fixed to the rotor shaft 20, and a resolver stator 70 fixed to the rear cover 66. The resolver rotor 68 is configured with a rotor core in which a number of annular steel plates are stacked in the axial direction in a position perpendicular to the center line O, and the resolver stator 70 is configured with a stator core in which a number of annular steel plates are stacked in the axial direction in a position perpendicular to the center line O, and a number of resolver coils 72 wound around a number of teeth provided on the inner peripheral surface of the stator core. The resolver coils 72 are covered by a resolver cover 74, and are connected to the outside via a connector 76.

[0030] The rear cover 66 is provided with a cylindrical resolver low 80 that positions and holds the resolver stator 70 therein, and is provided in the axial direction so as to protrude toward the rotor 12. The outer diameter of the resolver low 80 is approximately the same as the outer diameter of the rotor 12, and protrudes to a position close to the axial end face of the rotor 12. As shown above the center line O in FIG. 6, the cooling fluid that should be circulated in the axial direction in the groove 42 and discharged to the outside of the rotor 12 may be obstructed by the resolver low 80 and may stagnate in the groove 42. In response to this, the resolver low 80 is provided with slits 82 extending in the axial direction at multiple locations around the center line O, and at least one of the slits 82 is provided at a position that coincides with the groove 42 around the center line O. In this embodiment, the resolver low 80 is provided with slits 82 at three locations located at 120° intervals around the center line O, and all of the three slits 82 are provided at positions that coincide with the groove 42. Each of the slits 82 opens at the tip of the resolver inlet 80, and as shown below the center line O in Figure 6, the cooling fluid circulated in the axial direction along the arrow A within the groove 42 at the position corresponding to the slit 82 is discharged directly into the slit 82.

[0031] That is, in the resolver-embedded rotating electric machine 60 of this embodiment, a resolver in-low 80 that positions and holds the resolver stator 70 is provided on the rear cover 66, and there is a risk that the discharge of the cooling fluid circulating axially through the groove 42 may be hindered by the resolver in-low 80. However, since the multiple slits 82 provided in the resolver in-low 80 are all provided at positions that coincide with the groove 42 around the center line O, the cooling fluid that has circulated axially through the groove 42 is discharged into the slits 82, thereby suppressing stagnation of the cooling fluid regardless of the presence of the resolver in-low 80, and appropriately reducing drag loss.

[0032] The grooves 42 other than the three grooves 42 at positions corresponding to the slits 82 also contribute to promoting the discharge of the cooling fluid. However, if a predetermined cooling fluid discharge performance can be obtained with only the three grooves 42 at positions corresponding to the slits 82, some or all of the other 12 grooves 42 may be eliminated, and the surface 40f of the molded resin part 40 may be a cylindrical surface centered on the same center line O as the protruding surfaces 34f of the teeth 34.

[0033] Fig. 7 is a schematic cross-sectional view corresponding to Fig. 1, and in comparison with the rotating electric machine 10, the rotating electric machine 90 does not have grooves 42 on the surfaces 40f of some (five in Fig. 7) of the 15 molded resin parts 40, and the surfaces 40f are cylindrical surfaces centered on the same center line O as the protruding surfaces 34f of the teeth 34. With such a rotating electric machine 90, the grooves 42 provided on the surfaces 40f of the 10 molded resin parts 40 promote the discharge of the cooling fluid, reducing drag loss due to stagnation of the cooling fluid, and other effects similar to those of the above embodiment can be obtained. In addition, the number of grooves 42 provided on each surface 40f of the molded resin portion 40 varies between 1 and 0, and the grooves 42 are unevenly spaced around the center line O. This makes the rotational fluctuations of the rotor 12 caused by the pressure difference in the cooling fluid due to the presence or absence of grooves 42 irregular. Furthermore, since the total number of grooves 42 is different from the number of teeth 34, resonance with the rotational fluctuations of the rotor 12 caused by torque fluctuations corresponding to the number of teeth 34 is suppressed, and the generation of vibrations and abnormal noise due to this resonance is suppressed.

[0034] 8 is a schematic cross-sectional view corresponding to FIG. 1. In comparison with the rotating electric machine 10, the rotating electric machine 92 has a pair of grooves 50, 52 shown in FIG. 4 provided on the surface 40f of some (five in FIG. 8) of the molded resin parts 40 at 15 locations, instead of the groove 42. That is, molded resin parts 40 having a single groove 42 provided on the surface 40f and molded resin parts 40 having a pair of grooves 50, 52 provided on the surface 40f are mixed around the center line O. According to such a rotating electric machine 92, the grooves 42 provided on the surface 40f of the molded resin parts 40 at ten locations and the grooves 50, 52 provided on the surface 40f of the molded resin parts 40 at five locations promote the discharge of the cooling fluid, and the drag loss caused by the stagnation of the cooling fluid is reduced, and other effects similar to those of the above embodiment can be obtained. In addition, the number of grooves 42, 50, 52 provided on each surface 40f of the molded resin portion 40 is either one or two, and the grooves 42, 50, 52 are unevenly spaced around the center line O. This makes the rotational fluctuations of the rotor 12 caused by the pressure difference in the cooling fluid depending on the presence or absence of the grooves 42, 50, 52 irregular. Furthermore, since the total number of grooves 42, 50, 52 is different from the number of teeth 34, resonance with the rotational fluctuations of the rotor 12 caused by torque fluctuations corresponding to the number of teeth 34 is suppressed, and the generation of vibrations and abnormal noise due to this resonance is suppressed.

[0035] The techniques of FIGS. 7 and 8 can also be applied to the resolver-embedded rotating electric machine 60 of FIGS. 5 and 6, provided that the multiple slits 82 of the resolver in-low 80 are provided at positions around the center line O that coincide with the molded resin part 40 in which the groove 42 or the grooves 50, 52 are provided.

[0036] Although the embodiments of the present invention have been described in detail above with reference to the drawings, these are merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0037] 10, 60, 90, 92: rotating electric machine 12: rotor 14: stator 30: stator core 34: teeth 34f: protruding surface 36: gap 38: coil 40: molded resin part 40f: surface 42, 50, 52: groove 62: resolver 66: rear cover (support member) 70: resolver stator 80: resolver in-low 82: slit O: center line

Claims

1. The rotor is disposed on the inner periphery of the stator so as to be rotatable about a center line common to the stator, and The stator includes: a stator core having a cylindrical shape and including a plurality of teeth protruding toward an inner periphery of the cylindrical shape and spaced apart by a predetermined gap in a circumferential direction around the center line; A plurality of coils are disposed in the gap so as to be wound around the plurality of teeth; a plurality of molded resin portions each of which is filled with a resin material so as to fill the gaps and cover the coil, and the surfaces of the molded resin portions each of which is substantially flush with the protruding surfaces of the teeth and forms an inner peripheral surface of the stator; In a rotating electric machine having a groove is provided on the surface of at least a part of the molded resin portions among the plurality of molded resin portions in an axial direction parallel to the center line, The total number of the grooves provided on the surface of the molded resin portion at the plurality of locations is different from the number of the teeth. A rotating electric machine characterized by:

2. A rotor having a cylindrical shape and arranged on the inner circumferential side of the stator so as to be rotatable about a center line common to the stator, The stator includes: a stator core having a cylindrical shape and including a plurality of teeth protruding toward an inner periphery of the cylindrical shape and spaced apart by a predetermined gap in a circumferential direction around the center line; A plurality of coils are disposed in the gap so as to be wound around the plurality of teeth; a plurality of molded resin portions each of which is filled with a resin material so as to fill the gaps and cover the coil, and the surfaces of the molded resin portions each of which is substantially flush with the protruding surfaces of the teeth and forms an inner peripheral surface of the stator; In a rotating electric machine having a groove is provided on the surface of at least a part of the molded resin portions among the plurality of molded resin portions in an axial direction parallel to the center line, The number of the grooves provided on the surface of each of the plurality of molded resin portions is different. A rotating electric machine characterized by:

3. A rotor having a cylindrical shape and arranged on the inner circumferential side of the stator so as to be rotatable about a center line common to the stator, The stator includes: a stator core having a cylindrical shape and including a plurality of teeth protruding toward an inner periphery of the cylindrical shape and spaced apart by a predetermined gap in a circumferential direction around the center line; A plurality of coils are disposed in the gap so as to be wound around the plurality of teeth; a plurality of molded resin portions each of which is filled with a resin material so as to fill the gaps and cover the coil, and the surfaces of the molded resin portions each of which is substantially flush with the protruding surfaces of the teeth and forms an inner peripheral surface of the stator; In a rotating electric machine having a groove is provided on the surface of at least a part of the molded resin portions among the plurality of molded resin portions in an axial direction parallel to the center line, the rotor is supported by a support member so as to be rotatable about the center line, and a resolver is disposed between the support member and the rotor in the axial direction, A cylindrical resolver in-low that positions and holds a resolver stator therein is provided on the support member so as to protrude toward the rotor, and the resolver in-low is provided with slits extending in the axial direction at a plurality of positions around the center line, The groove is provided at a position that coincides with at least one of the plurality of slits around the center line. A rotating electric machine characterized by:

Images