Rotating electric machine

Abstract

According to one embodiment, an external fan (22) of a rotating electrical machine (10) includes a base (101) and a plurality of blades (102), and generates an air flow in a direction (Da2) opposite to a first direction (Da1) by rotating integrally with a shaft (14) regardless of a rotation direction of the shaft (14a). The base (101) has an outer peripheral surface (101a) having an annular shape around a rotation center axis (Ax) and having a diameter that decreases toward a first direction (Da1), and the base (01) is joined to the shaft (14). The blades (102) protrude from the outer peripheral surface (101a) of the base (101), are arranged at intervals in the circumferential direction of the rotation center axis (Ax), and are connected to each other only by the base (01).

Description

Technical Field

[0001] Generally speaking, embodiments described herein relate to rotating electrical machines. Background Art

[0002] Conventionally, a rotary electric machine including an external fan coupled to a shaft outside a housing and an external fan cover for covering the external fan is known, and the rotary electric machine cools the housing and the inside of the housing by airflow generated by the external fan. This type of external fan includes a base coupled to the shaft, a plurality of blades protruding from the base, and an annular shroud connecting the tip portions of the blades. That is, the blades are connected to each other through the base and the shroud.

[0003] A related technology is disclosed in Japanese Patent Application Publication No. 2019-187129.

[0004] The conventional external fan is provided with a shield, which has the problem of complicated structure.

[0005] A problem to be solved by the present invention is to obtain a rotating electrical machine with a novel construction which makes it possible to simplify the structure of an external fan. Summary of the invention

[0006] A rotating electric machine according to an embodiment includes a housing, a stator, a rotor, a shaft, an external fan and an external fan cover. The stator is accommodated in the housing and fixed to the housing. The rotor is accommodated in the housing and can rotate relative to the stator around a rotation center axis. The shaft is partially accommodated in the housing, combined with the rotor, and can rotate around the rotation center axis integrally with the rotor. The external fan is combined with the shaft outside the housing in a first direction relative to the axial direction of the rotation center axis of the housing. The external fan cover covers the external fan and has a hole, and the space configured with the external fan is connected to the outside of the space via the hole. The external fan includes a base and a plurality of blades. The base has an outer peripheral surface and is combined with the shaft. The outer peripheral surface has an annular shape around the rotation center axis, and the diameter of these annular shapes decreases as they move toward the first direction. The plurality of blades protrude from the outer peripheral surface, are arranged at intervals in the circumferential direction of the rotation center axis, and are connected to each other only by the base. Regardless of the rotation direction of the shaft, the integral rotation of the external fan with the shaft generates an airflow in a direction opposite to the first direction.

[0007] According to the present invention, for example, a rotating electric machine having a novel configuration that can simplify the structure of an external fan can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a cross-sectional view schematically showing a rotating electrical machine according to a first embodiment;

[0009] Figure 2is a perspective view showing a bearing support and an external fan of the rotating electrical machine of the first embodiment;

[0010] Figure 3 is a cross-sectional view schematically showing a part of the rotating electrical machine of the first embodiment;

[0011] Figure 4 is a cross-sectional view schematically showing a part of a rotating electrical machine according to a second embodiment;

[0012] Figure 5 is a cross-sectional view schematically showing a part of a rotating electric machine of a third embodiment; and

[0013] Figure 6 It is a diagram showing simulation results of the second embodiment and the third embodiment. DETAILED DESCRIPTION

[0014] Hereinafter, exemplary embodiments of the present invention are disclosed. The configurations of the embodiments described below and the functions and effects brought about by these configurations are merely examples. The present invention can also be implemented by configurations other than the configurations disclosed in the following embodiments. In addition, according to the present invention, at least one of the various effects (including derivative effects) brought about by these configurations can be obtained.

[0015] In addition, the drawings are schematic, and the dimensional relationship of each element, the ratio of each element, etc. may be different from the real one. In addition, the drawings may include parts with different dimensional relationships and ratios. In addition, in this specification, serial numbers are only used to distinguish parts, components, parts, positions, directions, etc., and are not used to indicate order or priority.

[0016] First embodiment

[0017] Figure 1 1 is a cross-sectional view schematically showing a rotary electric machine 10 of the first embodiment. The rotary electric machine 10 is a so-called fully enclosed fan-cooled rotary electric machine, used as a motor or a generator, for example. It should be noted that the rotary electric machine 10 is not limited to this example.

[0018] The rotary 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 internal fan 21, an external fan 22, and an external fan cover 23. In the present embodiment, the external fan cover 23 and the housing 13 constitute a storage body 26. It should be noted that the rotary electric machine 10 is not limited to this example.

[0019] The stator 11 includes a stator core 31 and a stator winding 32. The stator core 31 is formed into a substantially cylindrical shape around a rotation center axis Ax. The rotation center axis Ax is the rotation center of the rotor 12 and the shaft 14 in the rotary electric machine 10, and is, for example, a virtual straight line passing through the center of the shaft 14. The stator winding 32 passes through slots formed in the stator core 31 and is attached to the stator core 31.

[0020] In this specification, for convenience, axial, radial and circumferential directions are defined. The axial direction is the direction along the rotation center axis Ax. The radial direction is the direction orthogonal to the rotation center axis Ax. The circumferential direction is the direction of rotation around the rotation center axis Ax.

[0021] 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 rotation center axis Ax. The second axial direction Da2 is a direction opposite to the first axial direction Da1. The first axial direction Da1 is an example of a first direction.

[0022] The rotor 12 includes a rotor core 41 and a conductor 42. The rotor core 41 is formed into a substantially cylindrical shape around the rotation center axis Ax, and is arranged inside the stator core 31. The conductors 42 are arranged at intervals in the circumferential direction. The conductor 42 includes, for example, conductor bars through which the rotor core 41 passes axially, and short-circuit rings coupled to axial ends of all the conductor bars.

[0023] The housing 13 includes a frame 51, two bearing brackets 52 and 53, a plurality of heat sinks 54, and a plurality of heat sinks 55 and 56 (see Figure 2 The frame 51 is formed into a substantially cylindrical shape around the rotation center axis Ax. The stator 11 and the rotor 12 are provided inside the frame 51. The stator core 31 is fixed to the frame 51.

[0024] The frame 51 has an inner face 51a, an outer face 51b, and a plurality of bosses 51c. The inner face 51a faces the interior of the housing 13. The outer face 51b is provided on the opposite side of the inner face 51a and faces the exterior of the housing 13. The bosses 51c protrude from the outer face 51b to the exterior of the housing 13 near the end of the frame 51 in the first axial direction Da1. The bosses 51c are provided at intervals in the circumferential direction.

[0025] The bearing bracket 52 is attached to the end of the frame 51 in the second axial direction Da2. The bearing bracket 53 is attached to the end of the frame 51 in the first axial direction Da1. The bearing brackets 52 and 53 close the inner space of the frame 51. The bearing brackets 52 and 53 support the corresponding bearings 15.

[0026] Figure 2 1 is a perspective view showing the bearing support 53 and the external fan 22 of the rotary electric machine 10 of the first embodiment. Figure 2 As shown in FIG. 5 , the bearing support 53 has an end surface 53a and an outer peripheral surface 53b. The end surface 53a faces the first axial direction Da1. The outer peripheral surface 53b has a cylindrical shape around the rotation center axis Ax and extends from the outer peripheral edge of the end surface 53a to the second axial direction Da2.

[0027] A plurality of heat sinks 55 are provided on the end surface 53a. The heat sinks 55 protrude from the end surface 53a in the first axial direction Da1. A plurality of heat sinks 56 are provided on the outer peripheral surface 53b. The heat sinks 56 protrude radially from the outer peripheral surface 53b. Figure 1 and Figure 3 In the figure, the heat sinks 55 and 56 are omitted.

[0028] 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 and the outside of the closed space Si substantially airtightly. It should be noted that the closed space Si can 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.

[0029] A plurality of heat sinks 54 protrude, for example, from the outer face 51b of the frame 51 to the outside of the housing 13. Each heat sink 54 extends substantially axially. The heat sink 54 may protrude from the bearing supports 52 and 53, or may extend in other directions.

[0030] The shaft 14 is formed into a substantially cylindrical shape extending along the rotation center axis Ax. The shaft 14 extends across the inside and outside of the housing 13. The shaft 14 has a middle portion 14a and two extended portions 14b and 14c.

[0031] 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 extension 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 rotation center axis Ax.

[0032] The extensions 14b and 14c are parts of the shaft 14 located outside the housing 13. The extension 14b protrudes from the end of the middle portion 14a in the second axial direction Da2 to the outside of the housing 13, beyond the bearing bracket 52. The extension 14c protrudes from the end of the middle portion 14a in the first axial direction Da1 to the outside of the housing 13, beyond the bearing bracket 53.

[0033] The extension portion 14b is provided with, for example, a flange, a keyway, or a spline, and is coupled to an external device to transmit rotation. As a result, the rotary electric machine 10 outputs torque to the external device, or receives torque from the external device.

[0034] The middle portion 14a of the shaft 14 is coupled to the rotor core 41 of the rotor 12. The rotor 12 and the shaft 14 are integrally rotatable about the rotation center axis Ax relative to the stator 11. The shaft 14 may be formed of a single member or a combination of a plurality of members.

[0035] The internal fan 21 is coupled to the middle portion 14a of the shaft 14 in the closed space Si of the housing 13. The internal fan 21 can rotate integrally with the shaft 14 around the rotation center axis Ax. The internal fan 21 rotates to generate an airflow of cooling gas in the closed space Si. The airflow passes, for example, approximately axially between the stator 11 and the rotor 12, and cools the stator 11 and the rotor 12.

[0036] 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 have a duct adjacent to the internal fan 21 and introducing the cooling gas into the rotating internal fan 21. In addition, the housing 13 may be provided with a flow path for returning the cooling gas that has passed through the stator 11 and the rotor 12 to the vicinity of the internal fan 21.

[0037] The external fan 22 is outside the housing 13 and is coupled to the extension 14c of the shaft 14. This enables the external fan 22 to rotate integrally with the rotor 12, the shaft 14 and the internal fan 21 around the rotation center axis Ax. The external fan 22 is, for example, a centrifugal fan that rotates around the rotation center axis Ax. The external fan 22 is made of, for example, a synthetic resin material. It should be noted that the material of the external fan 22 is not limited to the above-mentioned materials. For example, the material of the external fan 22 may be a metal material. The external fan 22 is a centrifugal fan that rotates to allow the gas to flow at least radially outward. For example, the external fan 22 rotates to allow the gas to flow radially outward and in the second axial direction Da2. It should be noted that the external fan 22 is not limited to the above-mentioned examples.

[0038] The external fan cover 23 is provided outside the housing 13 to cover the external fan 22. The external fan cover 23 is made of metal, for example. The external fan cover 23 includes an end wall 61 and a peripheral wall 62. Inside the external fan cover 23, a guide wall 63 is provided. The guide wall 63 is an example of a wall. The external fan cover 23 is not limited to this example. The guide wall 63 is also called a partition wall or a partition plate.

[0039] The end wall 61 is disposed at a position spaced apart from the housing 13, the shaft 14, and the external fan 22 in the first axial direction Da1. For example, the end wall 61 is formed into a substantially disc shape substantially orthogonal to the rotation center axis Ax. The outer diameter of the end wall 61 is larger than the outer diameter of the end of the frame 51 in the first axial direction Da1, and larger than the outer diameter of the bearing bracket 53. The shape of the end wall 61 is not limited to this example.

[0040] The end wall 61 has an inner face 61a and an outer face 61b. The inner face 61a faces the second axial direction Da2. The inner face 61a faces the housing 13, the shaft 14 and the external fan 22 at a certain interval. The outer face 61b is provided on the opposite side of the inner face 61a and faces the first axial direction Da1.

[0041] The peripheral wall 62 is formed into a generally cylindrical shape extending generally in the second axial direction Da2 from the outer edge of the end wall 61. The inner diameter of the peripheral wall 62 is larger than the outer diameter of the end of the frame 51 in the first axial direction Da1 and larger than the outer diameter of the bearing support 53.

[0042] The peripheral wall 62 surrounds the bearing support 53 and the end of the frame 51 in the first axial direction Da1. The peripheral wall 62 is radially spaced from the outer face 51b of the frame 51 and the bearing support 53. As a result, a gap G is formed between the peripheral wall 62 and the housing 13. The peripheral wall 62 is fixed to the boss 51c of the frame 51 by, for example, bolts 65.

[0043] The end wall 61 and the peripheral wall 62 cover the bearing bracket 53 of the housing 13, the extension 14c of the shaft 14, and the external fan 22. The external fan cover 23 forms (establishes, defines) a flow path space Sc surrounded by the bearing bracket 53, the end wall 61, and the peripheral wall 62. The extension 14c of the shaft 14 and the external fan 22 are arranged 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 Scr is an example of a space.

[0044] The outer fan cover 23 is provided with a plurality of air inlet holes 71. In the present embodiment, the air inlet holes 71 are provided in the end wall 61. The air inlet holes 71 penetrate the end wall 61 in the axial direction and are open to the inner surface 61a and the outer surface 61b of the end wall 61. As a result, the flow path space Sc is connected to the outside of the flow path space Scr via the air inlet holes 71. The air inlet holes 71 may be provided in the peripheral wall 62. The air inlet holes 71 are an example of a hole. The air inlet holes 71 are also referred to as air inlets.

[0045] The end portion of the flow path space Sc in the first axial direction Da1 communicates with the outside through the plurality of air inlet holes 71. The end portion of the flow path space Sc in the second axial direction Da2 communicates with the outside through the gap G.

[0046] The external fan 22 rotates to draw external air into the flow path space Sc through the air inlet hole 71. As a result, an airflow in the second axial direction Da2 toward the external fan 22 is generated. The airflow of external air generated by the rotating external fan 22 is discharged to the outside of the flow path space Sc, for example, through the gap G, and flows along the outside 51b of the frame 51. In other words, an airflow along the outside 51b of the frame 51 is generated. Regardless of whether the shaft 14 rotates in the first rotation direction or in the direction opposite to the first rotation direction, the above-mentioned airflow is generated in the same manner. In other words, the rotation as one with the shaft 14 generates an airflow in the second axial direction Da2 regardless of the rotation direction of the shaft 14.

[0047] The airflow of the external air flows along the fins 54, 55, and 56 to exchange heat with the frame 51. As a result, the airflow of the external air passes through the frame 51, cooling the stator 11 coupled to the frame 51 and the cooling gas in the closed space Si.

[0048] The guide wall 63 is arranged in the flow path space Sc, that is, inside the external fan cover 23. The guide wall 63 is located in the first axial direction Da1 relative to the external fan 22. The guide wall 63 protrudes from the inner surface of the external fan cover 23 toward the rotation center axis Ax. The guide wall 63 has an annular (circular) shape around the rotation center axis Ax. That is, the guide wall 63 is provided with a hole 64 that penetrates the guide wall 63 in the axial direction. For example, the guide wall 63 forms a flow path that guides the external air sucked from the air inlet hole 71 to the external fan 22, and a flow path that guides the external air sent by the external fan 22 to the gap G.

[0049] Next, the configuration of the external fan 22 will be described in detail. Figure 3 It is a cross-sectional view schematically showing a part of the rotating electrical machine 10 according to the first embodiment.

[0050] like Figure 2 and Figure 3 As shown in , the external fan 22 includes a base 101 and a plurality of (e.g., three) blades 102. The base 101 and the blades 102 are, for example, integrally formed. The base 101 and the blades 102 can be configured as separate components and connected to each other. Alternatively, the base 101 and the blades 102 can be composed of a combination of multiple components.

[0051] The base 101 is coupled (fixed) to the shaft 14. The base 101 has a conical appearance in which the diameter decreases toward the first axial direction Da1. The base 101 has an outer peripheral surface 101a, a bottom surface 101b, an end portion 101c, and an end portion 101d.

[0052] The outer peripheral surface 101a has an annular shape around the rotation center axis Ax and a shape whose diameter decreases as it moves toward the first axial direction Da1 (first direction). For example, the outer peripheral surface 101a is a conical surface. Specifically, the outer peripheral surface 101a is centered on the rotation center axis A and is along a virtual conical surface M1 whose diameter decreases as it moves toward the first axial direction Da1.

[0053] The bottom surface 101b faces the second axial direction Da2. The bottom surface 101b is provided with a recessed portion 101e recessed in the first axial direction Da1. The end portion of the shaft 14 in the first axial direction Da1 is embedded in the recessed portion 101e. The recessed portion 101e is also referred to as an opening portion.

[0054] The end portion 101 d is an end portion (tip portion) of the base 101 in the first axial direction Da1 .

[0055] The end portion 101 c is an end portion (outer peripheral edge portion) of the base 101 in the radial direction.

[0056] Each blade 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 regular intervals in the circumferential direction of the rotation center axis Ax. The blades 102 are formed in a triangular flat plate shape. Specifically, the blades 102 have a triangular shape ( Figure 3 ). The blade 102 protrudes from the base 101 so that the thickness direction of the blade 102 is orthogonal to the circumferential direction.

[0057] The blade 102 has a base end portion 102a and a tip end portion 102b. The base end portion 102a is connected to the outer peripheral surface 101a of the base 101. The tip end portion 102b is an end portion opposite to the base end portion 102a. In other words, the tip end portion 102b is an end portion in the first axial direction Da1. The blades 102 are connected to each other only through the base 101. That is, in the present embodiment, a shield connecting the blades 102 is not provided.

[0058] A distance E1 between the tip portion 102b of the blade 102 and the guide wall 63 in the axial direction and a distance E2 between the end portion 101c of the base 101 and the inner peripheral surface 63a of the guide wall 63a in the radial direction are appropriately set.

[0059] As described above, the rotary electric machine 10 of the present 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 accommodated in the housing 13 and fixed to the housing 13. The rotor 12 is accommodated in the housing 13 and can rotate around the rotation center axis Ax relative to the stator 11. The shaft 14 is partially accommodated in the housing 13, coupled to the rotor 12, and can rotate around the rotation center axis Ax integrally with the rotor 12. The external fan 22 is coupled to the shaft 14 outside the housing 13 in the first axial direction Da1 (first direction) in the axial direction of the rotation center axis Ax relative to the housing 13. The external fan cover 23 covers the external fan 22 and is provided with an air inlet hole 71 (hole), wherein the flow path space Sc (space) in which the external fan 22 is arranged is communicated with the outside of the flow path space Sc via the air inlet hole 71. The external fan 22 includes a base 101 and a plurality of blades 102, and rotates integrally with the shaft 14 to generate an airflow in a direction opposite to the first axial direction Da1 (first direction) (i.e., in the second axial direction Da2) regardless of the rotation direction of the shaft 14. The base 101 has an outer peripheral surface 101a having an annular shape around the rotation center axis Ax and having a diameter that decreases as it goes toward the first axial direction Da1 (first direction), and the base 101 is coupled to the shaft 14. The blades 102 each protrude from the outer peripheral surface 101a of the base 101, are disposed at intervals in the circumferential direction of the rotation center axis Ax, and are connected to each other only through the base 101.

[0060] According to this configuration, since the blades 102 of the external fan 22 are connected to each other only through the base 101, the configuration of the external fan 22 can be simplified compared to a configuration in which the blades 102 are connected through the base 101 and the shroud. Therefore, it is possible to reduce the manufacturing costs of the external fan 22 and the rotary electric machine 10. According to the above configuration, since the outer peripheral surface 101a of the base 101 in the external fan 22 has an annular shape around the rotation center axis Ax, and the diameter decreases as it goes toward the first axial direction Da1 (first direction), for example, compared to a configuration in which the outer peripheral surface 101 has the same diameter at each position in the first axial direction Da1, the flow rate can be easily increased, and the loss can be easily reduced.

[0061] Furthermore, the blade 102 has a flat plate shape.

[0062] According to such a configuration, the shape of the blade 102 can be simplified compared to a configuration in which the blade 102 is curved. Therefore, the manufacturing costs of the external fan 22 and the rotary electric machine 10 can be further reduced.

[0063] Furthermore, the blade 102 has a triangular plate shape.

[0064] According to such a configuration, the blade 102 can be manufactured relatively easily.

[0065] In addition, the rotary electric machine 10 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 relative to the outer fan 22, and the guide wall 63 protrudes from the outer fan cover 23a toward the rotation center axis Ax and has an annular shape around the rotation center axis Ax.

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

[0067] Second embodiment

[0068] Figure 4 It is a cross-sectional view schematically showing a part of the rotary electric machine 10 according to the second embodiment.

[0069] like Figure 4 As shown in , the main difference between this embodiment and the first embodiment is that an external fan 22A, a bearing bracket 53A and an external fan cover 23A are provided to replace the external fan 22, the bearing bracket 53 and the external fan cover 23 in the first embodiment. Hereinafter, the difference between this embodiment and the first embodiment will be mainly described.

[0070] Similar to the external fan 22, the external fan 22A includes a base 101 and a plurality of blades 102. However, the external fan 22A of the present embodiment is different from the external fan 22 of the first embodiment in the shape of the base 101.

[0071] The base 101 is formed in a cylindrical shape whose diameter decreases toward the first axial direction Da1. The base 101 has an outer peripheral surface 101a, an end portion 101c, and an end portion 101d.

[0072] The outer peripheral surface 101a has an annular shape around the rotation center axis Ax and a shape whose diameter decreases toward the first axial direction Da1 (first direction). As an example, the outer peripheral surface 101a is along a virtual conical surface M1.

[0073] The end portion 101d is provided with a hole 103 which penetrates the end portion 101d in the axial direction. The end portion of the shaft 14 in the first axial direction Da1 is embedded in the hole 103. The hole 103 is also referred to as an opening.

[0074] The bearing support 53A is different in shape from the bearing support 53. The end face 53a of the bearing support 53A has an inner portion 53aa, an inclined portion 53ab, and an outer portion 53ac. The inner portion 53aa is a portion on the radial inner side of the end face 53a, and is substantially flat. The outer portion 53ac is a portion on the radial outer side 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 as it moves toward the first axial direction Da1.

[0075] In addition, the outer fan cover 23A includes 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 to connect the end wall 61 and the peripheral wall 62. The connecting wall 66 has a diameter that decreases toward the first axial direction Da1. The guide wall 63 is connected to the connecting wall 66.

[0076] As described above, in the present embodiment, the base 101 of the external fan 22A has a cylindrical shape.

[0077] According to such a configuration, the weight of the base 101 and the weight of the external fan 22A can be reduced compared to a configuration in which the base 101 has a solid configuration.

[0078] Third embodiment

[0079] Figure 5 It is a cross-sectional view schematically showing a part of a rotating electrical machine 10 according to the third embodiment.

[0080] like Figure 5 As shown in , the main difference between the present embodiment and the second embodiment is that an external fan 22B is provided instead of the external fan 22A of the second embodiment. Hereinafter, the difference between the present embodiment and the second embodiment will be mainly described.

[0081] Similar to the external fan 22A, the external fan 22B includes a base 101 and a plurality of blades 102. However, the external fan 22B of the present embodiment is different from the external fan 22A of the second embodiment in the shape of the blades 102. The blades 102 of the external fan 22B are in a trapezoidal flat plate shape.

[0082] Simulation of the Second and Third Embodiments

[0083] Figure 6 : is a graph showing simulation results of the second embodiment and the third embodiment. The present inventors conducted a simulation for examining the relationship between the flow rate and the loss of the external fans 22A and 22B of the second embodiment and the third embodiment. Figure 6 The horizontal axis in represents flow rate, while Figure 6 The vertical axis in represents the loss. Figure 6The line L1 in FIG. 1 represents the target value with a good balance between flow and loss. Figure 6 It can be seen that the external fan 22A with triangular blades 102 obtains a result that is closer to the line L1 as a whole than the external fan 22 with trapezoidal blades 102. In other words, it can be seen that the balance between flow and loss is better in the configuration with triangular blades 102 than in the configuration with trapezoidal blades 102.

[0084] In the above embodiment, the blade 102 has a triangular or trapezoidal shape, but the present invention is not limited thereto. The blade 102 may have a polygonal shape other than a triangular, trapezoidal or semicircular shape. In the above embodiment, an example in which the number of blades 102 is three is shown, but the present invention is not limited thereto. The number of blades 102 may be other numbers other than three.

Claims

1. A rotating electrical machine, comprising: case; a stator received in the housing and fixed to the housing; a rotor accommodated in the housing and rotatable relative to the stator about a rotation center axis; a shaft, partially accommodated in the housing, coupled to the rotor, and rotatable integrally with the rotor about the rotation center axis; an external fan coupled to the shaft outside the housing in a first direction in the axial direction of the rotation center axis relative to the housing; and an external fan cover covering the external fan and having a hole, through which the space where the external fan is arranged communicates with the outside of the space, The external fan comprises: a base having an outer peripheral surface and coupled to the shaft, the outer peripheral surface being in an annular shape around the rotation center axis and having a diameter that decreases toward the first direction, and A plurality of blades protrude from the outer peripheral surface, are arranged at intervals in the circumferential direction of the rotation center axis, and are connected to each other only through the base. Regardless of the rotation direction of the shaft, airflow is generated in a direction opposite to the first direction by the external fan rotating integrally with the shaft.

2. The rotating electrical machine according to claim 1, wherein The blade has a flat plate shape.

3. The rotating electrical machine according to claim 1, wherein The blade has a triangular plate shape.

4. The rotating electrical machine according to claim 1, comprising: A wall is provided in the outer fan cover, is located in the first direction relative to the outer fan, protrudes from the outer fan cover toward the rotation center axis, and has an annular shape surrounding the rotation center axis.

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