Rotary electric machine

Abstract

To obtain a rotary electric machine having a new configuration which enables simplification of a structure of an outer fan.SOLUTION: An outer fan 22 of a rotary electric machine 10 includes: a base 101; and a plurality of blades 102 and rotates integrally with a shaft 14 to generate airflow in an opposite direction Da2 of a first direction Da1, regardless of a rotation direction of the shaft 14. The base 101 has an outer peripheral surface 101a, having an annular shape formed around a rotation center axis Ax and having a diameter which gradually reduces in the first direction Da1, and is coupled to the shaft 14. The blades 102 protrude from the outer peripheral surface 101a of the base 101 and are arranged at intervals in a circumferential direction of the rotation center axis Ax and connected with each other only by the base 101.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] An embodiment of the present invention relates to a rotating electric machine. [Background technology]

[0002] Conventionally, a rotating electric machine is known that includes an external fan coupled to a shaft outside a housing and an external fan covering the external fan, and cools the housing and the inside of the housing with an airflow generated by the external fan. One such type of external fan has a base coupled to the shaft, multiple blades protruding from the base, and an annular shroud connecting the tips of the multiple blades. In other words, the multiple blades are connected to each other by the base and the shroud. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-187129 A Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional fan fans have a problem in that they are provided with a shroud, making their configuration complicated.

[0005] One of the problems to be solved by the present invention is to provide a rotating electric machine with a novel configuration that can simplify the configuration of an external fan. [Means for solving the problem]

[0006] a rotor housed in the housing and rotatable around a rotation axis relative to the stator; a shaft partly housed in the housing and connected to the rotor and rotatable around the rotation axis together with the rotor; an external fan connected to the shaft outside the housing on a first direction side of the axial direction of the rotation axis relative to the housing; and an external fan cover covering the external fan and having a hole communicating a space in which the external fan is arranged with the outside of the space, the external fan having an outer circumferential surface that is annular around the rotation axis and whose diameter decreases as it approaches the first direction, the external fan having a base connected to the shaft, and a plurality of blades each protruding from the outer circumferential surface, arranged at intervals circumferentially of the rotation axis, and connected to each other only by the base, and rotating together with the shaft regardless of the rotation direction of the shaft, generates an airflow in the opposite direction to the first direction. Effect of the Invention

[0007] According to the present invention, for example, it is possible to obtain a rotating electric machine with a novel configuration that can simplify the configuration of the external fan. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view that illustrates a schematic configuration of a rotating electric machine according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a bearing bracket and an external fan of the rotating electric machine according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view that diagrammatically illustrates a portion of the rotating electric machine of the first embodiment. [Figure 4] FIG. 4 is a cross-sectional view that illustrates a schematic view of a part of a rotating electric machine according to the second embodiment. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a schematic view of a part of a rotating electric machine according to a third embodiment. [Figure 6] FIG. 6 is a diagram showing the simulation results of the second and third embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below and the actions and effects brought about by the configurations are merely examples. The present invention can be realized by configurations other than those disclosed in the following embodiments. Furthermore, according to the present invention, it is possible to obtain at least one of the various effects (including derivative effects) obtained by the configurations.

[0010] In addition, the drawings are schematic, and the dimensional relationships and ratios of each element may differ from reality. Furthermore, the drawings may include parts whose dimensional relationships and ratios differ from one another. In this specification, ordinal numbers are used only to distinguish between parts, members, sites, positions, directions, etc., and do not indicate order or priority.

[0011] <First embodiment> 1 is a cross-sectional view that shows a schematic diagram of a rotating electric machine 10 according to a first embodiment. The rotating electric machine 10 is a so-called totally enclosed fan-cooled rotating electric machine, and is used as, for example, a motor or a generator. However, the rotating electric machine 10 is not limited to this example.

[0012] The rotating electric machine 10 includes a stator 11, a rotor 12, a housing 13, a shaft 14, a plurality of (for example, two) bearings 15, an inner fan 21, an outer fan 22, and an outer fan cover 23. In this embodiment, the outer fan cover 23 and the housing 13 form a housing 26. Note that the rotating electric machine 10 is not limited to this example.

[0013] The stator 11 has a stator core 31 and a stator winding 32. The stator core 31 is formed in a substantially cylindrical shape surrounding a rotation axis Ax. The rotation axis Ax is the center of rotation of the rotor 12 and the shaft 14 in the rotating electric machine 10, and is, for example, an imaginary straight line passing through the center of the shaft 14. The stator winding 32 is attached to the stator core 31 by passing through slots provided in the stator core 31.

[0014] In this specification, for convenience, the axial direction, radial direction, and circumferential direction are defined. The axial direction is a direction along the central axis of rotation Ax. The radial direction is a direction perpendicular to the central axis of rotation Ax. The circumferential direction is a direction of rotation around the central axis of rotation Ax.

[0015] The axial direction includes a first axial direction Da1 and a second axial direction Da2. The first axial direction Da1 is a direction along the central axis of rotation Ax. The second axial direction Da2 is the opposite direction to the first axial direction Da1. The first axial direction Da1 is an example of a first direction.

[0016] The rotor 12 has a rotor core 41 and conductors 42. The rotor core 41 is formed in a substantially cylindrical shape surrounding the central axis of rotation Ax, and is disposed inside the stator core 31. The conductors 42 are disposed at intervals from one another in the circumferential direction. The conductors 42 have, for example, conductor bars that axially penetrate the rotor core 41, and short-circuit rings that are coupled to the axial ends of all the conductor bars.

[0017] The housing 13 has a frame 51, two bearing brackets 52, 53, a plurality of heat dissipation fins 54, and a plurality of heat dissipation fins 55, 56 (see FIG. 2). The frame 51 is formed in a substantially cylindrical shape surrounding the central axis of rotation Ax. The stator 11 and the rotor 12 are disposed inside the frame 51. The stator core 31 is fixed to the frame 51.

[0018] The frame 51 has an inner surface 51a, an outer surface 51b, and multiple bosses 51c. The inner surface 51a faces the inside of the housing 13. The outer surface 51b is located on the opposite side of the inner surface 51a and faces the outside of the housing 13. The bosses 51c protrude from the outer surface 51b to the outside of the housing 13 near an end of the frame 51 in the first axial direction Da1. The multiple bosses 51c are arranged at intervals in the circumferential direction.

[0019] The bearing bracket 52 is attached to an end of the frame 51 in the second axial direction Da2. The bearing bracket 53 is attached to an end of the frame 51 in the first axial direction Da1. The bearing brackets 52 and 53 close the internal space of the frame 51. Each of the bearing brackets 52 and 53 supports a corresponding bearing 15.

[0020] Fig. 2 is a perspective view showing a bearing bracket 53 and an external fan 22 of the rotating electric machine 10 of the first embodiment. As shown in Fig. 2, the bearing bracket 53 has an end face 53a and an outer circumferential surface 53b. The end face 53a faces the first axial direction Da1. The outer circumferential surface 53b is cylindrical around the central rotation axis Ax and extends from the outer circumferential edge of the end face 53a in the second axial direction Da2.

[0021] A plurality of heat dissipating fins 55 are provided on the end face 53a. The heat dissipating fins 55 protrude from the end face 53a in the first axial direction Da1. A plurality of heat dissipating fins 56 are provided on the outer circumferential face 53b. The plurality of heat dissipating fins 56 protrude in the radial direction from the outer circumferential face 53b. Note that the plurality of heat dissipating fins 55, 56 are not shown in Figs. 1 and 3.

[0022] A closed space Si is provided inside the housing 13. The housing 13 accommodates the stator 11 and the rotor 12 in the closed space Si. The housing 13 seals the closed space Si substantially airtightly from the outside of the closed space Si. The closed space Si may be expanded to the outside of the frame 51 by a device such as a cooler attached to the housing 13. The closed space Si is filled with a cooling gas such as air.

[0023] The heat dissipating fins 54 protrude, for example, from the outer surface 51b of the frame 51 to the outside of the housing 13. Each of the heat dissipating fins 54 extends substantially in the axial direction. The heat dissipating fins 54 may protrude from the bearing brackets 52 and 53, or may extend in another direction.

[0024] The shaft 14 is formed in a generally cylindrical shape extending along the central axis of rotation Ax. The shaft 14 extends between the inside and the outside of the housing 13. The shaft 14 has a middle portion 14a and two outer extending portions 14b, 14c.

[0025] The middle portion 14a is a part of the shaft 14 located inside the housing 13. The middle portion 14a is located between the two extending portions 14b, 14c. Both ends of the middle portion 14a in the axial direction are supported by bearings 15. As a result, the shaft 14 is supported by the bearings 15 so as to be rotatable around the central axis of rotation Ax.

[0026] The extension portions 14b and 14c are parts of the shaft 14 located outside the housing 13. The extension portion 14b protrudes from the end of the middle portion 14a in the second axial direction Da2 beyond the bearing bracket 52 to the outside of the housing 13. The extension portion 14c protrudes from the end of the middle portion 14a in the first axial direction Da1 beyond the bearing bracket 53 to the outside of the housing 13.

[0027] The extension portion 14b is provided with, for example, a flange, a key groove, or a spline, and is coupled to an external device so as to be able to transmit rotation, whereby the rotating electric machine 10 outputs torque to the external device or receives torque from the external device.

[0028] Middle portion 14a of shaft 14 is coupled to rotor core 41 of rotor 12. Rotor 12 and shaft 14 can rotate integrally about rotation center axis Ax relative to stator 11. Note that shaft 14 may be formed of a single member, or may be formed by combining a plurality of members.

[0029] The inner fan 21 is coupled to the middle part 14a of the shaft 14 in the closed space Si of the housing 13. The inner fan 21 can rotate integrally with the shaft 14 around the central axis of rotation Ax. The inner fan 21 generates an airflow of cooling gas in the closed space Si by rotating. The airflow passes between the stator 11 and the rotor 12 in the approximate axial direction, for example, to cool the stator 11 and the rotor 12.

[0030] The housing 13 may be provided with various structures for circulating the cooling gas in the closed space Si. For example, the housing 13 may be adjacent to the inner fan 21 and have a duct that introduces the cooling gas into the rotating inner fan 21. The housing 13 may also be provided with a flow path that returns the cooling gas that has passed through the stator 11 and the rotor 12 to the vicinity of the inner fan 21.

[0031] The outer fan 22 is coupled to the outer extension portion 14c of the shaft 14 outside the housing 13. This allows the outer fan 22 to rotate around the rotation axis Ax together with the rotor 12, the shaft 14, and the inner fan 21. The outer fan 22 is, for example, a centrifugal fan that rotates around the rotation axis Ax. The outer fan 22 is made of, for example, a synthetic resin material. Note that the material of the outer fan 22 is not limited to the above. For example, the material of the outer fan 22 may be a metal material. The outer fan 22 is a centrifugal fan that can flow gas at least radially outward by rotating. As an example, the outer fan 22 can flow gas radially outward and toward the second axial direction Da2 by rotating. Note that the outer fan 22 is not limited to the above.

[0032] The external fan cover 23 is located outside the housing 13 and covers the external fan 22. The external fan cover 23 is made of, for example, metal. The external fan cover 23 has an end wall 61 and a peripheral wall 62. A guide wall 63 is provided inside the external fan cover 23. The guide wall 63 is an example of a wall. However, the external fan cover 23 is not limited to this example. The guide wall 63 is also called a partition wall or partition plate.

[0033] The end wall 61 is disposed at a position spaced apart from the housing 13, the shaft 14, and the outer fan 22 in the first axial direction Da1. The end wall 61 is formed, for example, in a substantially disk shape substantially perpendicular to the central rotation axis Ax. The outer diameter of the end wall 61 is longer than the outer diameter of the end of the frame 51 in the first axial direction Da1 and longer than the outer diameter of the bearing bracket 53. Note that the shape of the end wall 61 is not limited to this example.

[0034] The end wall 61 has an inner surface 61a and an outer surface 61b. The inner surface 61a faces the second axial direction Da2. The inner surface 61a faces the housing 13, the shaft 14, and the outer fan 22 via a gap. The outer surface 61b is located on the opposite side of the inner surface 61a and faces the first axial direction Da1.

[0035] The peripheral wall 62 is formed in a generally cylindrical shape extending approximately in the second axial direction Da2 from the outer edge of the end wall 61. The inner diameter of the peripheral wall 62 is longer than the outer diameter of the end of the frame 51 in the first axial direction Da1 and is longer than the outer diameter of the bearing bracket 53.

[0036] The peripheral wall 62 surrounds the bearing bracket 53 and an end of the frame 51 in the first axial direction Da1. The peripheral wall 62 is radially spaced apart from the outer surface 51b of the frame 51 and the bearing bracket 53. This forms a gap G between the peripheral wall 62 and the housing 13. The peripheral wall 62 is fixed to the boss 51c of the frame 51 by bolts 65, for example.

[0037] The end wall 61 and the peripheral wall 62 cover the bearing bracket 53 of the housing 13, the outer extension 14c of the shaft 14, and the outer fan 22. The outer fan cover 23 forms (defines, partitions) a flow path space Sc surrounded by the bearing bracket 53, the end wall 61, and the peripheral wall 62. The outer extension 14c of the shaft 14 and the outer fan 22 are disposed in the flow path space Sc. An inner surface 61a of the end wall 61 faces the inside of the flow path space Sc. The flow path space Sc is an example of a space.

[0038] The outer fan cover 23 is provided with a plurality of air intake holes 71. In this embodiment, the air intake holes 71 are provided in the end wall 61. The air intake holes 71 penetrate the end wall 61 in the axial direction and open to the inner surface 61a and the outer surface 61b of the end wall 61. As a result, the air intake holes 71 communicate between the flow path space Sc and the outside of the flow path space Sc. The air intake holes 71 may be provided in the peripheral wall 62. The air intake holes 71 are an example of a hole. The air intake holes 71 are also referred to as an air intake port.

[0039] An end portion of the flow passage space Sc in the first axial direction Da1 communicates with the outside through the plurality of air intake holes 71. An end portion of the flow passage space Sc in the second axial direction Da2 communicates with the outside through the gap G.

[0040] By rotating, the external fan 22 can suck outside air from the intake hole 71 into the flow path space Sc. This generates an airflow in the second axial direction Da2 toward the external fan 22. The airflow of outside air generated by the rotating external fan 22 is discharged to the outside of the flow path space Sc through the gap G, for example, and flows along the outer surface 51b of the frame 51. That is, an airflow along the outer surface 51b of the frame 51 is generated. The above airflow is generated in the same manner whether the shaft 14 rotates in the first rotation direction or in the direction opposite to the first rotation direction. That is, an airflow in the second axial direction Da2 is generated by rotating integrally with the shaft 14 regardless of the rotation direction of the shaft 14.

[0041] The outside air flows along the heat dissipation fins 54, 55, and 56, thereby exchanging heat with the frame 51. As a result, the outside air passes through the frame 51 to cool the stator 11 coupled to the frame 51 and the cooling gas in the closed space Si.

[0042] The guide wall 63 is provided in the flow path space Sc, i.e., in the external fan cover 23. The guide wall 63 is located further in the first axial direction Da1 than the external fan 22. The guide wall 63 protrudes from the inner surface of the external fan cover 23 toward the rotation central axis Ax. The guide wall 63 is annular (ring-shaped) about the rotation central axis Ax. That is, the guide wall 63 is provided with a hole 64 penetrating the guide wall 63 in the axial direction. The guide wall 63 forms, for example, a flow path that guides the outside air sucked in from the intake hole 71 to the external fan 22, and a flow path that guides the outside air sent by the external fan 22 to the gap G.

[0043] Next, a detailed description will be given of the configuration of the external fan 22. Fig. 3 is a cross-sectional view that shows a schematic view of a part of the rotating electric machine 10 of the first embodiment.

[0044] 2 and 3, the outer fan 22 has a base 101 and a plurality of (three, for example) blades 102. The base 101 and the plurality of blades 102 are, for example, integrally molded. Note that the base 101 and the plurality of blades 102 may be formed of separate members and joined together. Also, the base 101 and the blades 102 may be formed of a combination of a plurality of members.

[0045] The base 101 is coupled (fixed) to the shaft 14. The base 101 has a conical appearance with a diameter that decreases toward the first axial direction Da1. The base 101 has an outer circumferential surface 101a, a bottom surface 101b, an end portion 101c, and an end portion 101d.

[0046] The outer peripheral surface 101a is annular about the central axis of rotation Ax and has a shape in which the diameter decreases toward the first axial direction Da1 (first direction). As an example, the outer peripheral surface 101a is a conical surface. That is, the outer peripheral surface 101a follows a virtual conical surface M1 that is centered on the central axis of rotation A and has a diameter that decreases toward the first axial direction Da1.

[0047] The bottom surface 101b faces the second axial direction Da2. The bottom surface 101b is provided with a recess 101e recessed in the first axial direction Da1. The end of the shaft 14 in the first axial direction Da1 is fitted into the recess 101e. The recess 101e is also referred to as an opening.

[0048] The end 101d is an end (tip) of the base 101 in the first axial direction Da1. The end portion 101c is the radially outer end portion (outer peripheral edge portion) of the base 101.

[0049] Each of the blades 102 protrudes from the outer peripheral surface 101a of the base 101. The blades 102 are arranged at intervals in the circumferential direction of the rotation center axis Ax. The blades 102 are arranged at equal intervals in the circumferential direction of the rotation center axis Ax. The blades 102 are formed in a triangular flat plate shape. In detail, when the blades 102 are viewed from the thickness direction of the blades 102, the blades 102 are triangular (FIG. 3). The blades 102 protrude from the base 101 so that the thickness direction of the blades 102 is perpendicular to the circumferential direction.

[0050] The blade 102 has a base end 102a and a tip end 102b. The base end 102a is connected to the outer circumferential surface 101a of the base 101. The tip end 102b is an end opposite to the base end 102a. In other words, the tip end 102b is an end in the first axial direction Da1. The multiple blades 102 are connected to each other only by the base 101. That is, in this embodiment, no shroud is provided to connect the multiple blades 102.

[0051] An axial distance E1 between the tip 102b of the blade 102 and the guide wall 63, and a radial distance E2 between the end 101c of the base 101 and the inner circumferential surface 63a of the guide wall 63 are appropriately set.

[0052] As described above, the rotating electric machine 10 of this embodiment includes the housing 13, the stator 11, the rotor 12, the shaft 14, the external fan 22, and the external fan cover 23. The stator 11 is housed in the housing 13 and fixed to the housing 13. The rotor 12 is housed in the housing 13 and is rotatable around the rotation axis Ax relative to the stator 11. A part of the shaft 14 is housed in the housing 13 and is coupled to the rotor 12 and is rotatable around the rotation axis Ax together with the rotor 12. The external fan 22 is coupled to the shaft 14 outside the housing 13 on the first axial direction Da1 (first direction) side of the axial direction of the rotation axis Ax relative to the housing 13. The external fan cover 23 covers the external fan 22 and is provided with an intake hole 71 (hole) that communicates between a flow path space Sc (space) in which the external fan 22 is arranged and the outside of the flow path space Sc. The external fan 22 has a base 101 and multiple blades 102, and generates an airflow in the opposite direction to the first axial direction Da1 (first direction), i.e., in the second axial direction Da2, by rotating integrally with the shaft 14 regardless of the rotation direction of the shaft 14. The base 101 has an outer circumferential surface 101a that is annular about the central axis of rotation Ax and has a diameter that decreases toward the first axial direction Da1 (first direction), and is coupled to the shaft 14. The multiple blades 102 each protrude from the outer circumferential surface 101a of the base 101, are arranged at intervals in the circumferential direction of the central axis of rotation Ax, and are connected to each other only by the base 101.

[0053] According to this configuration, the multiple blades 102 of the external fan 22 are connected to each other only by the base 101, so the configuration of the external fan 22 can be simplified compared to a configuration in which the multiple blades 102 are connected by the base 101 and a shroud. This makes it possible to reduce the manufacturing costs of the external fan 22 and, in turn, the rotating electric machine 10. Furthermore, according to the above configuration, the outer circumferential surface 101a of the base 101 in the external fan 22 is annular about the central axis of rotation Ax and the diameter decreases toward the first axial direction Da1 (first direction). Therefore, for example, compared to a configuration in which the outer circumferential surface 101a has the same diameter at each position in the first axial direction Da1, it is easier to increase the flow rate and reduce losses.

[0054] Moreover, the blade 102 is flat.

[0055] According to such a configuration, the shape of the blades 102 can be simplified compared to a configuration in which the blades 102 are curved. Therefore, the manufacturing costs of the outer fan 22 and therefore the rotating electric machine 10 can be further reduced.

[0056] Moreover, the blade 102 is in the form of a triangular plate.

[0057] With this configuration, the blade 102 can be manufactured relatively easily.

[0058] The rotating electric machine also includes a guide wall 63 (wall). The guide wall 63 (wall) is provided inside the outer fan cover 23 in the first axial direction Da1 further than the outer fan 22, protrudes from the outer fan cover 23 toward the rotation central axis Ax, and is annular about the rotation central axis Ax.

[0059] According to such a configuration, the guide wall 63 (wall) allows the rotation of the external fan 22 to generate an airflow in the first axial direction Da1 (first direction) more efficiently.

[0060] <Second embodiment> FIG. 4 is a cross-sectional view that diagrammatically illustrates a portion of a rotating electrical machine 10 according to the second embodiment.

[0061] 4, the present embodiment differs from the first embodiment mainly in that an external fan 22A, a bearing bracket 53A, and an external fan cover 23A are provided instead of the external fan 22, the bearing bracket 53, and the external fan cover 23 of the first embodiment. The following mainly describes the differences between the first embodiment and this embodiment.

[0062] Like the external fan 22, the external fan 22A has a base 101 and a plurality of blades 102. However, the shape of the base 101 of the external fan 22A of the present embodiment is different from that of the external fan 22 of the first embodiment.

[0063] The base 101 is formed in a cylindrical shape whose diameter decreases in the first axial direction Da1. The base 101 has an outer circumferential surface 101a, an end 101c, and an end 101d.

[0064] The outer circumferential surface 101a is annular about the central axis of rotation Ax and has a shape in which the diameter decreases toward the first axial direction Da1 (first direction). As an example, the outer circumferential surface 101a is aligned along an imaginary conical surface M1.

[0065] The end portion 101d is provided with a hole 103 that passes through the end portion 101d in the axial direction. The end portion of the shaft 14 in the first axial direction Da1 is fitted into the hole 103. The hole 103 is also referred to as an opening portion.

[0066] The bearing bracket 53A has a different shape from the bearing bracket 53. The end face 53a of the bearing bracket 53A has an inner portion 53aa, an inclined portion 53ab, and an outer portion 53ac. The inner portion 53aa is a radially inner portion of the end face 53a and is substantially flat. The outer portion 53ac is a radially outer portion of the end face 53a and is substantially flat. The inclined portion 53ab is located between the inner portion 53aa and the outer portion 53ac, and the diameter of the inclined portion 53ab decreases toward the first axial direction Da1.

[0067] The outer fan cover 23A also has an end wall 61, a peripheral wall 62, and a connecting wall 66. The connecting wall 66 is provided between the end wall 61 and the peripheral wall 62, and connects the end wall 61 and the peripheral wall 62. The diameter of the connecting wall 66 decreases toward the first axial direction Da1. The guide wall 63 is connected to the connecting wall 66.

[0068] As described above, in this embodiment, the base 101 of the external fan 22B is cylindrical.

[0069] According to such a configuration, the weight of the base 101 and therefore the external fan 22B can be reduced compared to a configuration in which the base 101 is solid.

[0070] <Third embodiment> FIG. 5 is a cross-sectional view that diagrammatically illustrates a portion of a rotating electric machine 10 according to the third embodiment.

[0071] 5, the present embodiment differs from the second embodiment mainly in that an external fan 22B is provided instead of the external fan 22A of the second embodiment. The following mainly describes the differences between the present embodiment and the second embodiment.

[0072] Like the external fan 22A, the external fan 22B has a base 101 and a plurality of blades 102. However, the external fan 22A of the present embodiment differs from the external fan 22A of the second embodiment in the shape of the blades 102. The blades 102 of the external fan 22A are trapezoidal flat plates.

[0073] <Simulation of the second and third embodiments> FIG. 6 is a diagram showing the simulation results of the second and third embodiments. The inventors performed a simulation to investigate the relationship between the flow rate and loss in the external fans 22A, 22B of the second and third embodiments. The horizontal axis of FIG. 6 is the flow rate, and the vertical axis of FIG. 6 is the loss. Line L1 in FIG. 6 indicates a target value that provides a good balance between the flow rate and loss. As can be seen from FIG. 6, the external fan 22A with triangular blades 102 generally obtained results that are closer to line L1 than the external fan 22B with trapezoidal blades 102. In other words, it was found that the balance between the flow rate and loss is better in the case of the external fan 22A with triangular blades 102 than in the case of the external fan 22B with trapezoidal blades 102.

[0074] In the above embodiment, the shape of the blades 102 is a triangle or a trapezoid, but is not limited thereto. The shape of the blades 102 may be, for example, a polygon other than a triangle or a trapezoid, or a semicircular shape. In addition, in the above embodiment, the number of blades 102 is three, but is not limited thereto. The number of blades 102 may be other than three.

[0075] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0076] 10... rotating electric machine, 11... stator, 12... rotor, 14... shaft, 22, 22A, 22B... external fan, 23, 23A... external fan cover, 63... guide wall (wall), 71... intake hole (hole), 101... base, 101a... outer peripheral surface, 102... blade, Ax... central axis of rotation, Da1... first axial direction (first direction), Da2... second axial direction (opposite direction), Sc... flow path space (space).

Claims

1. A housing and a stator housed in the housing and fixed to the housing; a rotor accommodated in the housing and rotatable about a rotation center axis relative to the stator; a shaft, a portion of which is housed in the housing and which is coupled to the rotor and is rotatable about the central axis of rotation together with the rotor; an external fan coupled to the shaft outside the housing on a first direction side of the axial direction of the rotation central shaft with respect to the housing; An external fan cover that covers the external fan and has a hole that communicates between a space in which the external fan is arranged and the outside of the space; Equipped with The outer fan is a base having an outer peripheral surface that is annular about the central axis of rotation and has a diameter that decreases in the first direction, the base being coupled to the shaft; A plurality of blades each protruding from the outer circumferential surface, arranged at intervals in a circumferential direction of the central axis of rotation, and connected to each other only by the base; having a rotating shaft that rotates together with the shaft regardless of the rotation direction of the shaft to generate an airflow in an opposite direction to the first direction; Rotating electric motor.

2. The blade is flat. The rotating electric machine according to claim 1 .

3. The blade is a triangular plate. The rotating electric machine according to claim 1 .

4. The outer fan cover is provided with a ring-shaped wall around the rotation central axis, the wall being located in the first direction relative to the outer fan and protruding from the outer fan cover toward the rotation central axis. The rotating electric machine according to claim 1 .

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