Rotary electric machine

Abstract

To provide a rotary electric machine having a novel configuration capable of simplifying the configuration of an external fan.SOLUTION: An external fan 22 of a rotary electric machine includes a base 101 and nine blades 102, and generates an air flow of an opposite direction Da1 of a first direction Da2 by rotating integrally with a shaft regardless of a rotation direction of the shaft. The base 101 has an annular shape around the rotational axis Ax, has an outer peripheral surface Da1 that becomes smaller toward the first direction 101a, and is coupled to the shaft. The nine blades 102 each protrude from the 101a of the outer peripheral surface of the base 101, are arranged at intervals in the circumferential direction of the rotational axis Ax, and are connected to 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] A rotating electric machine has been known that includes an external fan coupled to a shaft outside a housing and another external fan covering the external fan, and that cools the housing and the interior of the housing with airflow generated by the external fan. One such external fan includes 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] Japanese Patent Application Publication No. 2019-187129 Summary of the Invention [Problem to be solved by the invention]

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

[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 the outer fan. [Means for solving the problem]

[0006] a rotor housed in the housing and rotatable around a rotational axis relative to the stator; a shaft partly housed in the housing and coupled to the rotor so as to rotate integrally with the rotor around the rotational axis; an outer fan coupled to the shaft outside the housing on a first direction side of the housing in the axial direction of the rotational axis; and an outer fan cover covering the outer fan and having holes communicating a space in which the outer fan is disposed with the outside of the space, the outer fan having an outer peripheral surface that is annular around the rotational axis and whose diameter decreases as it extends in the first direction, a base coupled to the shaft, and nine blades that protrude from the outer peripheral surface, are arranged at intervals circumferentially of the rotational axis, and are connected to each other only by the base, and rotate integrally with the shaft regardless of the rotational direction of the shaft, thereby generating an airflow in the opposite direction to the first direction. [Effects 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 outer fan. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view that schematically shows a rotating electric machine according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view showing in detail a part of the rotating electric machine of the first embodiment. [Figure 3] FIG. 3 is a perspective view showing the outer fan of the rotary electric machine of the first embodiment, illustrating the front side of the outer fan. [Figure 4] FIG. 4 is a front view showing the outer fan of the rotating electric machine according to the first embodiment. [Figure 5] FIG. 5 is a perspective view showing the outer fan of the rotary electric machine of the first embodiment, illustrating the back side of the outer fan. [Figure 6] FIG. 6 is a rear view showing the outer fan of the rotating electric machine of the first embodiment. [Figure 7] FIG. 7 is a cross-sectional view that schematically shows a part of a rotating electric machine according to the second embodiment. [Figure 8] FIG. 8 is a diagram showing the simulation results of the first and second embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0009] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions and effects brought about by the configurations, are merely examples. The present invention can also 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] Furthermore, the drawings are schematic, and the dimensional relationships and ratios of elements may differ from reality. Furthermore, the drawings may contain parts with different dimensional relationships and ratios. Furthermore, in this specification, ordinal numbers are used only to distinguish between parts, members, locations, positions, directions, etc., and do not indicate order or priority.

[0011] First Embodiment FIG. 1 is a cross-sectional view that schematically shows 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, for example, as an electric motor or a generator. The rotating electric machine 10 is a three-phase, six-pole rotating electric machine. 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. However, 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 central axis of rotation Ax. The central axis of rotation Ax is the center of rotation of the rotor 12 and shaft 14 in the rotating electric machine 10, and is, for example, an imaginary 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] For convenience, the terms axial direction, radial direction, and circumferential direction are defined herein. The axial direction is the direction along the central axis of rotation Ax. The radial direction is the direction perpendicular to the central axis of rotation Ax. The circumferential direction is the direction of rotation around the central axis of rotation Ax.

[0015] The axial directions include 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 pass through the rotor core 41 in the axial direction and short-circuit rings that are coupled to the axial ends of all of the conductor bars.

[0017] The housing 13 has a frame 51, two bearing brackets 52 and 53, and a plurality of heat dissipation fins 54. 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 and an outer surface 51b. 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.

[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, 53 close the internal space of the frame 51. Each of the bearing brackets 52, 53 supports a corresponding bearing 15.

[0020] The bearing bracket 53 has an end face 53a, an outer circumferential surface, and multiple bosses 51c. The end face 53a faces the first axial direction Da1. The outer circumferential surface 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. Multiple fins are provided on the end face 53a and the outer circumferential surface. The bosses 51c are provided on the outer circumferential surface of the bearing bracket 53 and protrude radially outward from the outer circumferential surface. The multiple bosses 51c are arranged circumferentially with intervals between them. An air (gas) passage is formed between two circumferentially adjacent bosses 51c, and air can pass through the passage in the axial direction.

[0021] FIG. 2 is a cross-sectional view showing in detail a portion of the rotating electric machine 10 of the first embodiment. Specifically, as shown in FIG. 2, the end face 53a of the bearing bracket 53 has an inner portion 53aa, an inclined portion 53ab, and an outer portion 53ac. The inner portion 53aa is the radially inner portion of the end face 53a and is substantially flat. The outer portion 53ac is the 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 has a diameter that decreases toward the first axial direction Da1.

[0022] As shown in Fig. 1, a closed space Si is provided inside the housing 13. The housing 13 houses 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 dissipation 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 dissipation fins 54 extends substantially in the axial direction. The heat dissipation 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 from the inside to 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 and 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] A middle portion 14a of the shaft 14 is coupled to a rotor core 41 of the rotor 12. The rotor 12 and the shaft 14 can rotate integrally around a central axis of rotation Ax relative to the stator 11. The shaft 14 may be formed of a single member or may be formed of a combination of multiple members.

[0029] The inner fan 21 is coupled to the middle portion 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 rotation axis Ax. As the inner fan 21 rotates, it generates an airflow of cooling gas in the closed space Si. The airflow passes, for example, between the stator 11 and the rotor 12 in a substantially axial direction, and cools 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 outward extending portion 14c of the shaft 14 outside the housing 13. This allows the outer fan 22 to rotate integrally with the rotor 12, the shaft 14, and the inner fan 21 around the central rotation axis Ax. The outer fan 22 is, for example, a centrifugal fan that rotates around the central 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 cause gas to flow at least radially outward by rotating. As an example, the outer fan 22 can cause gas to flow 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 outer fan cover 23 is located outside the housing 13 and covers the outer fan 22. The outer fan cover 23 is made of, for example, metal. The outer fan cover 23 has an end wall 61 and a peripheral wall 62. A guide wall 63 is also provided inside the outer fan cover 23. The guide wall 63 is an example of a wall. However, the outer 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 that is 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 is also 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 opposite 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 also 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 spaced radially 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 portion 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 portion 14c of the shaft 14 and the outer fan 22 are disposed in the flow path space Sc. The 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 axially penetrate the end wall 61 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 also 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 of the flow path space Sc in the first axial direction Da1 communicates with the outside through the plurality of intake holes 71. Furthermore, an end of the flow path space Sc in the second axial direction Da2 communicates with the outside through the passages and gaps G between the plurality of bosses 51c.

[0040] 2, in detail, the outer fan cover 23 has a connecting wall 66 in addition to the end wall 61 and the peripheral wall 62. 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 this connecting wall 66.

[0041] As the external fan 22 rotates, it can draw outside air into the flow path space Sc through the intake holes 71. 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 passes, for example, through the passages and gaps G between the multiple bosses 51c and is released to the outside of the flow path space Sc, and flows along the outer surface 51b of the frame 51. That is, an airflow is generated along the outer surface 51b of the frame 51. The above airflow is generated in the same way whether the shaft 14 rotates in the first rotation direction or in the direction opposite to the first rotation direction. That is, by rotating integrally with the shaft 14, an airflow in the second axial direction Da2 is generated regardless of the rotation direction of the shaft 14.

[0042] The outside air flow flows along the heat dissipation fins 54, thereby exchanging heat with the frame 51. As a result, the outside air flow cools the stator 11 coupled to the frame 51 and the cooling gas in the closed space Si through the frame 51. Furthermore, the outside air flow exchanges heat with the bearing bracket 53 as it flows along the outer surface (end surface 53a, outer peripheral surface) of the bearing bracket 53. As a result, the outside air flow cools the stator 11 and the cooling gas in the closed space Si also through the bearing bracket 53.

[0043] The guide wall 63 is provided in the flow path space Sc, i.e., in the outer fan cover 23. The guide wall 63 is located further in the first axial direction Da1 than the outer fan 22. The guide wall 63 protrudes from the inner surface of the outer fan cover 23 toward the rotation center axis Ax. The guide wall 63 has an annular (ring-like) shape around the rotation center axis Ax. That is, the guide wall 63 is provided with holes 64 that penetrate the guide wall 63 in the axial direction. The guide wall 63 forms, for example, a flow path that guides outside air sucked in through the intake holes 71 to the outer fan 22, and a flow path that guides outside air sent by the outer fan 22 to the passages between the multiple bosses 51c and the gaps G.

[0044] Next, the configuration of the external fan 22 will be described in detail. Fig. 3 is a perspective view showing the external fan 22 of the rotating electric machine 10 of the first embodiment, and is a diagram showing the front side of the external fan 22. Fig. 4 is a front view showing the external fan 22 of the rotating electric machine 10 of the first embodiment. Fig. 5 is a perspective view showing the external fan 22 of the rotating electric machine 10 of the first embodiment, and is a diagram showing the back side of the external fan 22. Fig. 6 is a back view showing the external fan 22 of the rotating electric machine 10 of the first embodiment.

[0045] As shown in Figures 2 to 6, the outer fan 22 has a base 101, nine blades 102, a connecting portion 103, and multiple ribs 104. The base 101, nine blades 102, connecting portion 103, and multiple ribs 104 are, for example, integrally molded. The base 101, nine blades 102, connecting portion 103, and ribs 104 may be formed from separate members and connected to each other. Alternatively, the base 101, blades 102, connecting portion 103, and ribs 104 may each be formed from a combination of multiple members.

[0046] The base 101 is coupled (fixed) to the shaft 14 via a coupling portion 103. The base 101 has a conical appearance with a diameter that decreases toward the first axial direction Da1. Specifically, the base 101 has a conical appearance with a diameter that decreases toward the first axial direction Da1 but without a vertex. In other words, the base 101 is cylindrical. The base 101 has an outer circumferential surface 101a, a back surface 101b, an end portion 101c, and an end portion 101d.

[0047] 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. More specifically, the outer peripheral surface 101a is an apexless conical shape in which the diameter decreases toward the first axial direction Da1. That is, the outer peripheral surface 101a follows a virtual conical surface M1 that is centered on the central axis of rotation Ax and whose diameter decreases toward the first axial direction Da1. Note that the outer peripheral surface 101a may also be a conical surface having an apex. The outer peripheral surface 101a has a radially outer end 101aa and a radially inner end 101ab.

[0048] The back surface 101b is the surface opposite to the outer peripheral surface 101a and extends along the outer peripheral surface 101a. That is, the back surface 101b 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). More specifically, the back surface 101b has a conical shape in which the diameter decreases toward the first axial direction Da1, but does not have an apex. That is, the back surface 101b extends along a virtual conical surface M1 that is centered on the central axis of rotation Ax and whose diameter decreases toward the first axial direction Da1. Note that the back surface 101b may also be a conical surface having an apex. The back surface 101b is also referred to as the inner peripheral surface.

[0049] The coupling portion 103 is formed in a cylindrical shape around the central axis of rotation Ax. An end portion of the coupling portion 103 on the first axial direction Da1 side is connected to the coupling portion 103. The coupling portion 103 is provided with a through hole 103a that penetrates in the axial direction. The shaft 14 is inserted into the through hole 103a.

[0050] Further, a key groove 101f is provided on the inner peripheral surface of the coupling portion 103. The key groove 101f penetrates the coupling portion 103 in the axial direction. As shown in FIG. 6, the key groove 101f overlaps in the radial direction with a key groove 14d (FIG. 2) provided in the shaft 14. A key 110 is fitted into the key groove 101f of the coupling portion 103 and the key groove 14d of the shaft 14, and this key 110 couples (fixes) the coupling portion 103 and the shaft 14, and ultimately couples (fixes) the outer fan 22 and the shaft 14. Note that the fixing structure between the outer fan 22 and the shaft 14 is not limited to the above.

[0051] The end 101d is the end (tip) of the base 101 in the first axial direction Da1. A recess 101e is provided in the end 101d. The recess 101e is recessed in the second axial direction Da2 and opens in the first axial direction Da1. A through-hole 103a opens in the bottom surface of the recess 101e. The end 101c is the radially outer end (outer peripheral edge) of the base 101.

[0052] The nine blades 102 each protrude from the outer peripheral surface 101a of the base 101. The nine blades 102 are arranged at intervals in the circumferential direction of the rotation center axis Ax. The nine blades 102 are arranged at equal intervals in the circumferential direction of the rotation center axis Ax. The blades 102 are formed in the shape of triangular flat plates. In detail, when the blades 102 are viewed from the thickness direction of the blades 102, the blades 102 are triangular (FIG. 2). The blades 102 protrude from the base 101 so that the thickness direction of the blades 102 is perpendicular to the circumferential direction.

[0053] The blade 102 has a base end 102a and a tip end 102b. The base end 102a is connected to the outer peripheral surface 101a of the base 101. The radially outer end of the base end 102a, i.e., the radially outer end 102c of the blade 102, is connected to (overlapped with) the radially outer end 101aa of the outer peripheral surface 101a. The radially inner end of the base end 102a, i.e., the radially inner end 102d of the blade 102, is spaced apart from the radially inner end 101ab of the outer peripheral surface 101a.

[0054] The tip end 102b is the end opposite to the base end 102a. In other words, the tip end 102b is the end in the first axial direction Da1. The nine blades 102 are connected to each other only by the base 101. In other words, in this embodiment, no shroud is provided to connect the nine blades 102.

[0055] 5 and 6, a plurality of ribs 104 are provided on the rear surface 101b of the base 101. As an example, three ribs 104 are provided. Note that the number of ribs 104 is not limited to the above.

[0056] The three ribs 104 each protrude from the back surface 101b of the base 101. The three ribs 104 are arranged at intervals in the circumferential direction of the rotation center axis Ax. The three ribs 104 are arranged at equal intervals in the circumferential direction of the rotation center axis Ax. The three ribs 104 are arranged in the axial direction with three of the nine blades 102. The ribs 104 are formed in the shape of a trapezoidal flat plate. More specifically, when the ribs 104 are viewed from the thickness direction of the blades 102, the ribs 104 are trapezoidal (FIG. 2). The ribs 104 protrude from the back surface 101b so that the thickness direction of the ribs 104 is perpendicular to the circumferential direction. Furthermore, the radially inner ends of the ribs 104 are connected to the outer circumferential surface of the connecting portion 103. That is, the ribs 104 are interposed between the back surface 101b of the base 101 and the outer peripheral surface of the connecting portion 103, and connect the back surface 101b of the base 101 to the outer peripheral surface of the connecting portion 103. These ribs 104 increase the strength and rigidity of the outer fan 22. The ribs 104 suppress deformation of the base 101. Note that the shape of the ribs 104 is not limited to the above.

[0057] As shown in FIG. 2, the axial distance E1 between the tip 102b of the blade 102 and the guide wall 63 and the radial distance E2 between the end 101c of the base 101 and the inner surface 63a of the guide wall 63 are set appropriately.

[0058] The number of blades 102 will be described. Research by the inventors has revealed that in a three-phase, six-pole rotating electric machine 10, the number of blades 102 of the external fan 22 that optimizes the air volume and loss (mechanical loss) caused by the airflow from the external fan 22 is nine. For this reason, nine blades 102 are provided in this embodiment. It has also been revealed that, for example, in a three-phase, four-pole rotating electric machine, the optimal number of blades 102 is three. Since the three-phase, six-pole rotating electric machine 10 of this embodiment has a lower rotation speed than a three-phase, four-pole rotating electric machine, the number of blades 102 is increased compared to a three-phase, four-pole rotating electric machine to ensure the air volume.

[0059] 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 relative to the stator 11 about the rotation axis Ax. A portion of the shaft 14 is housed in the housing 13 and is coupled to the rotor 12 so as to be rotatable integrally with the rotor 12 about the rotation axis Ax. The external fan 22 is coupled to the shaft 14 outside the housing 13 on the side of the first axis direction Da1 (first direction) of the axial direction of the rotation axis Ax with respect 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 a flow path space Sc (space) in which the external fan 22 is disposed with the outside of the flow path space Sc. The outer fan 22 has a base 101 and nine blades 102, and rotates integrally with the shaft 14 regardless of the direction of rotation of the shaft 14 to generate an airflow in the opposite direction to the first axial direction Da1 (first direction), i.e., in the second axial direction Da2. The base 101 has an outer peripheral surface 101a that is annular about the central axis of rotation Ax and whose diameter decreases toward the first axial direction Da1 (first direction), and is connected to the shaft 14. The nine blades 102 each protrude from the outer peripheral 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.

[0060] According to this configuration, the nine blades 102 of the outer fan 22 are connected to each other only by the base 101, which simplifies the configuration of the outer fan 22 compared to a configuration in which the nine blades 102 are connected by the base 101 and a shroud. This reduces the manufacturing costs of the outer fan 22 and, ultimately, the rotating electric machine 10. Furthermore, according to the above configuration, the outer peripheral surface 101a of the base 101 in the outer fan 22 is annular about the central axis of rotation Ax and the diameter decreases toward the first axial direction Da1 (first direction). This makes it easier to increase the flow rate and reduce losses compared to, for example, a configuration in which the diameter of the outer peripheral surface 101a is the same at each position in the first axial direction Da1.

[0061] The blades 102 are flat.

[0062] According to this 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 electrical machine 10 can be further reduced.

[0063] The blades 102 are triangular plate-shaped.

[0064] With this configuration, the blade 102 can be manufactured relatively easily.

[0065] 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.

[0066] According to this configuration, the guide wall 63 (wall) allows the rotation of the outer fan 22 to generate an airflow in the first axial direction Da1 (first direction) more efficiently.

[0067] In addition, the base 101 of the outer fan 22 is cylindrical.

[0068] With this configuration, the weight of the base 101 and therefore the outer fan 22 can be reduced compared to a configuration in which the base 101 is solid.

[0069] <Second embodiment> FIG. 7 is a cross-sectional view that schematically shows a part of a rotating electrical machine 10 according to the second embodiment.

[0070] 7, the present embodiment is different from the first embodiment mainly in that an external fan 22A is provided instead of the external fan 22 of the first embodiment. The following mainly describes the differences between the present embodiment and the first embodiment.

[0071] Like the outer fan 22, the outer fan 22A has a base 101 and nine blades 102. However, the outer fan 22 of this embodiment differs from the outer fan 22 of the first embodiment in the shape of the blades 102. The blades 102 of the outer fan 22A are trapezoidal flat plates.

[0072] <Simulation of the first and second embodiments> FIG. 8 is a diagram showing simulation results for the first and second embodiments. The inventors conducted a simulation to investigate the relationship between the flow rate and loss in the outer fans 22, 22A of the first and second embodiments. The horizontal axis of FIG. 8 represents the flow rate, and the vertical axis of FIG. 8 represents the loss. Line L1 in FIG. 8 indicates the target value that provides a good balance between the flow rate and loss. As can be seen from FIG. 8, the outer fan 22 with triangular blades 102 generally achieved results closer to line L1 than the outer fan 22A with trapezoidal blades 102. In other words, it was found that the triangular blades 102 provided a better balance between the flow rate and loss than the configuration with trapezoidal blades 102.

[0073] In the above embodiment, the blades 102 are shaped like a triangle or a trapezoid, but are not limited to this. The blades 102 may be shaped like a polygon other than a triangle or a trapezoid, or may be semicircular, for example.

[0074] Although several 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 embodied 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 within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0075] 10...rotating electric machine, 11...stator, 12...rotor, 14...shaft, 22, 22A...external fan, 23...external fan cover, 63...guide wall (wall), 71...intake hole (hole), 101...base, 101a...outer peripheral surface, 102...blade, Ax...rotation center axis, Da1...first axial direction (first direction), Da2...second axial direction (opposite direction), Sc...flow path space (space).

Claims

1. The 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 integrally with the rotor; an outer fan coupled to the shaft outside the housing on a first direction side of the housing in the axial direction of the rotation central shaft; an outer fan cover that covers the outer fan and has a hole that communicates a space in which the outer fan is arranged with the outside of the space; Equipped with The outer fan is a base coupled to the shaft, the 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; Nine blades each protruding from the outer circumferential surface, arranged at intervals in the circumferential direction of the rotation central shaft, and connected to each other only by the base; and 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 blades are triangular plate-shaped. The rotating electric machine according to claim 1 .

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

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